Changeset - d3835a56401d
[Not reviewed]
0 5 0
Christopher Esterhuyse - 5 years ago 2020-09-22 16:28:07
christopher.esterhuyse@gmail.com
flattened some structures for simplicity. added more internal doc comments
5 files changed with 203 insertions and 136 deletions:
0 comments (0 inline, 0 general)
src/protocol/mod.rs
Show inline comments
 
mod arena;
 
mod ast;
 
mod eval;
 
pub(crate) mod inputsource;
 
mod lexer;
 
// mod library;
 
mod parser;
 

	
 
lazy_static::lazy_static! {
 
    /// Conveniently-provided protocol description initialized with a zero-length PDL string.
 
    /// Exposed to minimize repeated initializations of this common protocol description.
 
    pub static ref TRIVIAL_PD: std::sync::Arc<ProtocolDescription> = {
 
        std::sync::Arc::new(ProtocolDescription::parse(b"").unwrap())
 
    };
 
}
 

	
 
use crate::common::*;
 
use crate::protocol::ast::*;
 
use crate::protocol::eval::*;
 
use crate::protocol::inputsource::*;
 
use crate::protocol::parser::*;
 

	
 
/// Description of a protocol object, used to configure new connectors.
 
/// (De)serializable.
 
#[derive(serde::Serialize, serde::Deserialize)]
 
#[repr(C)]
 
pub struct ProtocolDescription {
 
    heap: Heap,
 
    source: InputSource,
 
    root: RootId,
 
}
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
pub(crate) struct ComponentState {
 
    prompt: Prompt,
 
}
 
pub(crate) enum EvalContext<'a> {
 
    Nonsync(&'a mut NonsyncProtoContext<'a>),
 
    Sync(&'a mut SyncProtoContext<'a>),
 
    // None,
 
}
 
//////////////////////////////////////////////
 

	
 
impl std::fmt::Debug for ProtocolDescription {
 
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
 
        write!(f, "(An opaque protocol description)")
 
    }
 
}
 
impl ProtocolDescription {
 
    pub fn parse(buffer: &[u8]) -> Result<Self, String> {
 
        let mut heap = Heap::new();
 
        let mut source = InputSource::from_buffer(buffer).unwrap();
 
        let mut parser = Parser::new(&mut source);
 
        match parser.parse(&mut heap) {
 
            Ok(root) => {
 
                return Ok(ProtocolDescription { heap, source, root });
 
            }
 
            Err(err) => {
 
                let mut vec: Vec<u8> = Vec::new();
 
                err.write(&source, &mut vec).unwrap();
 
                Err(String::from_utf8_lossy(&vec).to_string())
 
            }
 
        }
 
    }
 
    pub(crate) fn component_polarities(
 
        &self,
 
        identifier: &[u8],
 
    ) -> Result<Vec<Polarity>, AddComponentError> {
 
        use AddComponentError::*;
 
        let h = &self.heap;
 
        let root = &h[self.root];
 
        let def = root.get_definition_ident(h, identifier);
 
        if def.is_none() {
 
            return Err(NoSuchComponent);
 
        }
 
        let def = &h[def.unwrap()];
 
        if !def.is_component() {
 
            return Err(NoSuchComponent);
 
        }
 
        for &param in def.parameters().iter() {
 
            let param = &h[param];
 
            let type_annot = &h[param.type_annotation];
 
            if type_annot.the_type.array {
 
                return Err(NonPortTypeParameters);
 
            }
 
            match type_annot.the_type.primitive {
 
                PrimitiveType::Input | PrimitiveType::Output => continue,
 
                _ => {
 
                    return Err(NonPortTypeParameters);
 
                }
 
            }
 
        }
 
        let mut result = Vec::new();
 
        for &param in def.parameters().iter() {
 
            let param = &h[param];
 
            let type_annot = &h[param.type_annotation];
 
            let ptype = &type_annot.the_type.primitive;
 
            if ptype == &PrimitiveType::Input {
 
                result.push(Polarity::Getter)
 
            } else if ptype == &PrimitiveType::Output {
 
                result.push(Polarity::Putter)
 
            } else {
 
                unreachable!()
 
            }
 
        }
 
        Ok(result)
 
    }
 
    // expects port polarities to be correct
 
    pub(crate) fn new_main_component(&self, identifier: &[u8], ports: &[PortId]) -> ComponentState {
 
        let mut args = Vec::new();
 
        for (&x, y) in ports.iter().zip(self.component_polarities(identifier).unwrap()) {
 
            match y {
 
                Polarity::Getter => args.push(Value::Input(InputValue(x))),
 
                Polarity::Putter => args.push(Value::Output(OutputValue(x))),
 
            }
 
        }
 
        let h = &self.heap;
 
        let root = &h[self.root];
 
        let def = root.get_definition_ident(h, identifier).unwrap();
 
        ComponentState { prompt: Prompt::new(h, def, &args) }
 
    }
 
}
 
impl ComponentState {
 
    pub(crate) fn nonsync_run<'a: 'b, 'b>(
 
        &'a mut self,
 
        context: &'b mut NonsyncProtoContext<'b>,
 
        pd: &'a ProtocolDescription,
 
    ) -> NonsyncBlocker {
 
        let mut context = EvalContext::Nonsync(context);
 
        loop {
 
            let result = self.prompt.step(&pd.heap, &mut context);
 
            match result {
 
                // In component definitions, there are no return statements
 
                Ok(_) => unreachable!(),
 
                Err(cont) => match cont {
 
                    EvalContinuation::Stepping => continue,
 
                    EvalContinuation::Inconsistent => return NonsyncBlocker::Inconsistent,
 
                    EvalContinuation::Terminal => return NonsyncBlocker::ComponentExit,
 
                    EvalContinuation::SyncBlockStart => return NonsyncBlocker::SyncBlockStart,
 
                    // Not possible to end sync block if never entered one
 
                    EvalContinuation::SyncBlockEnd => unreachable!(),
 
                    EvalContinuation::NewComponent(decl, args) => {
 
                        // Look up definition (TODO for now, assume it is a definition)
 
                        let h = &pd.heap;
 
                        let def = h[decl].as_defined().definition;
 
                        let init_state = ComponentState { prompt: Prompt::new(h, def, &args) };
 
                        context.new_component(&args, init_state);
 
                        // Continue stepping
 
                        continue;
 
                    }
 
                    // Outside synchronous blocks, no fires/get/put happens
 
                    EvalContinuation::BlockFires(_) => unreachable!(),
 
                    EvalContinuation::BlockGet(_) => unreachable!(),
 
                    EvalContinuation::Put(_, _) => unreachable!(),
 
                },
 
            }
 
        }
 
    }
 

	
 
    pub(crate) fn sync_run<'a: 'b, 'b>(
 
        &'a mut self,
 
        context: &'b mut SyncProtoContext<'b>,
 
        pd: &'a ProtocolDescription,
 
    ) -> SyncBlocker {
 
        let mut context = EvalContext::Sync(context);
 
        loop {
 
            let result = self.prompt.step(&pd.heap, &mut context);
 
            match result {
 
                // Inside synchronous blocks, there are no return statements
 
                Ok(_) => unreachable!(),
 
                Err(cont) => match cont {
 
                    EvalContinuation::Stepping => continue,
 
                    EvalContinuation::Inconsistent => return SyncBlocker::Inconsistent,
 
                    // First need to exit synchronous block before definition may end
 
                    EvalContinuation::Terminal => unreachable!(),
 
                    // No nested synchronous blocks
 
                    EvalContinuation::SyncBlockStart => unreachable!(),
 
                    EvalContinuation::SyncBlockEnd => return SyncBlocker::SyncBlockEnd,
 
                    // Not possible to create component in sync block
 
                    EvalContinuation::NewComponent(_, _) => unreachable!(),
 
                    EvalContinuation::BlockFires(port) => match port {
 
                        Value::Output(OutputValue(port)) => {
 
                            return SyncBlocker::CouldntCheckFiring(port);
 
                        }
 
                        Value::Input(InputValue(port)) => {
 
                            return SyncBlocker::CouldntCheckFiring(port);
 
                        }
 
                        _ => unreachable!(),
 
                    },
 
                    EvalContinuation::BlockGet(port) => match port {
 
                        Value::Output(OutputValue(port)) => {
 
                            return SyncBlocker::CouldntReadMsg(port);
 
                        }
 
                        Value::Input(InputValue(port)) => {
 
                            return SyncBlocker::CouldntReadMsg(port);
 
                        }
 
                        _ => unreachable!(),
 
                    },
 
                    EvalContinuation::Put(port, message) => {
 
                        let value;
 
                        match port {
 
                            Value::Output(OutputValue(port_value)) => {
 
                                value = port_value;
 
                            }
 
                            Value::Input(InputValue(port_value)) => {
 
                                value = port_value;
 
                            }
 
                            _ => unreachable!(),
 
                        }
 
                        let payload;
 
                        match message {
 
                            Value::Message(MessageValue(None)) => {
 
                                // Putting a null message is inconsistent
 
                                return SyncBlocker::Inconsistent;
 
                            }
 
                            Value::Message(MessageValue(Some(buffer))) => {
 
                                // Create a copy of the payload
src/runtime/communication.rs
Show inline comments
 
use super::*;
 
use crate::common::*;
 
use core::ops::{Deref, DerefMut};
 

	
 
////////////////
 
// Guard protecting an incrementally unfoldable slice of MapTempGuard elements
 
struct MapTempsGuard<'a, K, V>(&'a mut [HashMap<K, V>]);
 
// Type protecting a temporary map; At the start and end of the Guard's lifetime, self.0.is_empty() must be true
 
struct MapTempGuard<'a, K, V>(&'a mut HashMap<K, V>);
 

	
 
struct BranchingNative {
 
    branches: HashMap<Predicate, NativeBranch>,
 
}
 
#[derive(Clone, Debug)]
 
struct NativeBranch {
 
    index: usize,
 
    gotten: HashMap<PortId, Payload>,
 
    to_get: HashSet<PortId>,
 
}
 
#[derive(Debug)]
 
struct BranchingProtoComponent {
 
    branches: HashMap<Predicate, ProtoComponentBranch>,
 
}
 
#[derive(Debug, Clone)]
 
struct ProtoComponentBranch {
 
    state: ComponentState,
 
    inner: ProtoComponentBranchInner,
 
    ended: bool,
 
}
 
struct CyclicDrainer<'a, K: Eq + Hash, V> {
 
    input: &'a mut HashMap<K, V>,
 
    inner: CyclicDrainInner<'a, K, V>,
 
}
 
struct CyclicDrainInner<'a, K: Eq + Hash, V> {
 
    swap: &'a mut HashMap<K, V>,
 
    output: &'a mut HashMap<K, V>,
 
}
 
trait ReplaceBoolTrue {
 
    fn replace_with_true(&mut self) -> bool;
 
}
 
impl ReplaceBoolTrue for bool {
 
    fn replace_with_true(&mut self) -> bool {
 
        let was = *self;
 
        *self = true;
 
        !was
 
    }
 
}
 
// CuUndecided provides a mostly immutable view into the ConnectorUnphased structure,
 
// making it harder to accidentally mutate its contents in a way that cannot be rolled back.
 
impl CuUndecided for ConnectorUnphased {
 
    fn logger_and_protocol_description(&mut self) -> (&mut dyn Logger, &ProtocolDescription) {
 
        (&mut *self.inner.logger, &self.proto_description)
 
        (&mut *self.logger, &self.proto_description)
 
    }
 
    fn logger(&mut self) -> &mut dyn Logger {
 
        &mut *self.inner.logger
 
        &mut *self.logger
 
    }
 
    fn proto_description(&self) -> &ProtocolDescription {
 
        &self.proto_description
 
    }
 
    fn native_component_id(&self) -> ComponentId {
 
        self.inner.native_component_id
 
        self.native_component_id
 
    }
 
}
 

	
 
////////////////
 
impl<'a, K, V> MapTempsGuard<'a, K, V> {
 
    fn reborrow(&mut self) -> MapTempsGuard<'_, K, V> {
 
        MapTempsGuard(self.0)
 
    }
 
    fn split_first_mut(self) -> (MapTempGuard<'a, K, V>, MapTempsGuard<'a, K, V>) {
 
        let (head, tail) = self.0.split_first_mut().expect("Cache exhausted");
 
        (MapTempGuard::new(head), MapTempsGuard(tail))
 
    }
 
}
 
impl<'a, K, V> MapTempGuard<'a, K, V> {
 
    fn new(map: &'a mut HashMap<K, V>) -> Self {
 
        assert!(map.is_empty()); // sanity check
 
        Self(map)
 
    }
 
}
 
impl<'a, K, V> Drop for MapTempGuard<'a, K, V> {
 
    fn drop(&mut self) {
 
        assert!(self.0.is_empty()); // sanity check
 
    }
 
}
 
impl<'a, K, V> Deref for MapTempGuard<'a, K, V> {
 
    type Target = HashMap<K, V>;
 
    fn deref(&self) -> &<Self as Deref>::Target {
 
        self.0
 
    }
 
}
 
impl<'a, K, V> DerefMut for MapTempGuard<'a, K, V> {
 
    fn deref_mut(&mut self) -> &mut <Self as Deref>::Target {
 
        self.0
 
    }
 
}
 
impl Connector {
 
    /// Read the message received by the given port in the previous synchronous round.
 
    pub fn gotten(&self, port: PortId) -> Result<&Payload, GottenError> {
 
        use GottenError as Ge;
 
        if let ConnectorPhased::Communication(comm) = &self.phased {
 
            match &comm.round_result {
 
                Err(_) => Err(Ge::PreviousSyncFailed),
 
                Ok(None) => Err(Ge::NoPreviousRound),
 
                Ok(Some(round_ok)) => round_ok.gotten.get(&port).ok_or(Ge::PortDidntGet),
 
            }
 
        } else {
 
            return Err(Ge::NoPreviousRound);
 
        }
 
    }
 
    /// Creates a new, empty synchronous batch for the connector and selects it.
 
    /// Subsequent calls to `put` and `get` with populate the new batch with port operations.
 
    pub fn next_batch(&mut self) -> Result<usize, WrongStateError> {
 
        // returns index of new batch
 
        if let ConnectorPhased::Communication(comm) = &mut self.phased {
 
            comm.native_batches.push(Default::default());
 
            Ok(comm.native_batches.len() - 1)
 
        } else {
 
            Err(WrongStateError)
 
        }
 
    }
 

	
 
    fn port_op_access(
 
        &mut self,
 
        port: PortId,
 
        expect_polarity: Polarity,
 
    ) -> Result<&mut NativeBatch, PortOpError> {
 
        use PortOpError as Poe;
 
        let Self { unphased: cu, phased } = self;
 
        let info = cu.inner.current_state.port_info.get(&port).ok_or(Poe::UnknownPolarity)?;
 
        if info.owner != cu.inner.native_component_id {
 
        let info = cu.current_state.port_info.get(&port).ok_or(Poe::UnknownPolarity)?;
 
        if info.owner != cu.native_component_id {
 
            return Err(Poe::PortUnavailable);
 
        }
 
        if info.polarity != expect_polarity {
 
            return Err(Poe::WrongPolarity);
 
        }
 
        match phased {
 
            ConnectorPhased::Setup { .. } => Err(Poe::NotConnected),
 
            ConnectorPhased::Communication(comm) => {
 
                let batch = comm.native_batches.last_mut().unwrap(); // length >= 1 is invariant
 
                Ok(batch)
 
            }
 
        }
 
    }
 

	
 
    /// Add a `put` operation to the connector's currently-selected synchronous batch.
 
    /// Returns an error if the given port is not owned by the native component,
 
    /// has the wrong polarity, or is already included in the batch.
 
    pub fn put(&mut self, port: PortId, payload: Payload) -> Result<(), PortOpError> {
 
        use PortOpError as Poe;
 
        let batch = self.port_op_access(port, Putter)?;
 
        if batch.to_put.contains_key(&port) {
 
            Err(Poe::MultipleOpsOnPort)
 
        } else {
 
            batch.to_put.insert(port, payload);
 
            Ok(())
 
        }
 
    }
 

	
 
    /// Add a `get` operation to the connector's currently-selected synchronous batch.
 
    /// Returns an error if the given port is not owned by the native component,
 
    /// has the wrong polarity, or is already included in the batch.
 
    pub fn get(&mut self, port: PortId) -> Result<(), PortOpError> {
 
        use PortOpError as Poe;
 
        let batch = self.port_op_access(port, Getter)?;
 
        if batch.to_get.insert(port) {
 
            Ok(())
 
        } else {
 
            Err(Poe::MultipleOpsOnPort)
 
        }
 
    }
 

	
 
    /// Participate in the completion of the next synchronous round, in which
 
    /// the native component will perform the set of prepared operations of exactly one
 
    /// of the synchronous batches. At the end of the procedure, the synchronous
 
    /// batches will be reset to a singleton set, whose only element is selected, and empty.
 
    /// The caller yields control over to the connector runtime to faciltiate the underlying
 
    /// coordination work until either (a) the round is completed with all components' states
 
    /// updated accordingly, (b) a distributed failure event resets all components'
 
    /// states to what they were prior to the sync call, or (c) the sync procedure encounters
 
    /// an unrecoverable error which ends the call early, and breaks the session and connector's
 
    /// states irreversably.
 
    /// Note that the (b) case necessitates the success of a distributed rollback procedure,
 
    /// which this component may initiate, but cannot guarantee will succeed in time or at all.
 
    /// consequently, the given timeout duration represents a duration in which the connector
 
    /// will make a best effort to fail the round and return control flow to the caller.
 
    pub fn sync(&mut self, timeout: Option<Duration>) -> Result<usize, SyncError> {
 
        let Self { unphased: cu, phased } = self;
 
        match phased {
 
            ConnectorPhased::Setup { .. } => Err(SyncError::NotConnected),
 
            ConnectorPhased::Communication(comm) => {
 
                match &comm.round_result {
 
                    Err(SyncError::Unrecoverable(e)) => {
 
                        log!(cu.logger(), "Attempted to start sync round, but previous error {:?} was unrecoverable!", e);
 
                        return Err(SyncError::Unrecoverable(e.clone()));
 
                    }
 
                    _ => {}
 
                }
 
                comm.round_result = Self::connected_sync(cu, comm, timeout);
 
                comm.round_index += 1;
 
                match &comm.round_result {
 
                    Ok(None) => unreachable!(),
 
                    Ok(Some(ok_result)) => Ok(ok_result.batch_index),
 
                    Err(sync_error) => Err(sync_error.clone()),
 
                }
 
            }
 
        }
 
    }
 
    // private function. mutates state but returns with round
 
    // result ASAP (allows for convenient error return with ?)
 
    fn connected_sync(
 
        cu: &mut ConnectorUnphased,
 
        comm: &mut ConnectorCommunication,
 
        timeout: Option<Duration>,
 
    ) -> Result<Option<RoundOk>, SyncError> {
 
        //////////////////////////////////
 
        use SyncError as Se;
 
        //////////////////////////////////
 

	
 
        log!(@MARK, cu.logger(), "sync start {}", comm.round_index);
 
        log!(
 
            cu.logger(),
 
            "~~~ SYNC called with timeout {:?}; starting round {}",
 
            &timeout,
 
            comm.round_index
 
        );
 
        log!(@BENCH, cu.logger(), "");
 

	
 
        // 1. run all proto components to Nonsync blockers
 
        // iterate
 
        let mut current_state = cu.inner.current_state.clone();
 
        let mut current_state = cu.current_state.clone();
 
        let mut branching_proto_components =
 
            HashMap::<ComponentId, BranchingProtoComponent>::default();
 
        let mut unrun_components: Vec<(ComponentId, ComponentState)> = cu
 
            .proto_components
 
            .iter()
 
            .map(|(&proto_id, proto)| (proto_id, proto.clone()))
 
            .collect();
 
        log!(cu.logger(), "Nonsync running {} proto components...", unrun_components.len());
 
        // drains unrun_components, and populates branching_proto_components.
 
        while let Some((proto_component_id, mut component)) = unrun_components.pop() {
 
            log!(
 
                cu.logger(),
 
                "Nonsync running proto component with ID {:?}. {} to go after this",
 
                proto_component_id,
 
                unrun_components.len()
 
            );
 
            let (logger, proto_description) = cu.logger_and_protocol_description();
 
            let mut ctx = NonsyncProtoContext {
 
                current_state: &mut current_state,
 
                logger,
 
                proto_component_id,
 
                unrun_components: &mut unrun_components,
 
            };
 
            let blocker = component.nonsync_run(&mut ctx, proto_description);
 
            log!(
 
                cu.logger(),
 
                "proto component {:?} ran to nonsync blocker {:?}",
 
                proto_component_id,
 
                &blocker
 
            );
 
            use NonsyncBlocker as B;
 
            match blocker {
 
                B::ComponentExit => drop(component),
 
                B::Inconsistent => return Err(Se::InconsistentProtoComponent(proto_component_id)),
 
                B::SyncBlockStart => {
 
                    branching_proto_components
 
                        .insert(proto_component_id, BranchingProtoComponent::initial(component));
 
                }
 
            }
 
        }
 
        log!(
 
            cu.logger(),
 
            "All {} proto components are now done with Nonsync phase",
 
            branching_proto_components.len(),
 
        );
 
        log!(@BENCH, cu.logger(), "");
 

	
 
        // Create temp structures needed for the synchronous phase of the round
 
        let mut rctx = RoundCtx {
 
            current_state,
 
            solution_storage: {
 
                let n = std::iter::once(SubtreeId::LocalComponent(cu.inner.native_component_id));
 
                let n = std::iter::once(SubtreeId::LocalComponent(cu.native_component_id));
 
                let c =
 
                    branching_proto_components.keys().map(|&cid| SubtreeId::LocalComponent(cid));
 
                let e = comm
 
                    .neighborhood
 
                    .children
 
                    .iter()
 
                    .map(|&index| SubtreeId::NetEndpoint { index });
 
                let subtree_id_iter = n.chain(c).chain(e);
 
                log!(
 
                    cu.inner.logger,
 
                    cu.logger,
 
                    "Children in subtree are: {:?}",
 
                    subtree_id_iter.clone().collect::<Vec<_>>()
 
                );
 
                SolutionStorage::new(subtree_id_iter)
 
            },
 
            spec_var_stream: cu.inner.current_state.id_manager.new_spec_var_stream(),
 
            spec_var_stream: cu.current_state.id_manager.new_spec_var_stream(),
 
            payload_inbox: Default::default(),
 
            deadline: timeout.map(|to| Instant::now() + to),
 
        };
 
        log!(cu.logger(), "Round context structure initialized");
 
        log!(@BENCH, cu.logger(), "");
 

	
 
        // Explore all native branches eagerly. Find solutions, buffer messages, etc.
 
        log!(
 
            cu.logger(),
 
            "Translating {} native batches into branches...",
 
            comm.native_batches.len()
 
        );
 
        let native_spec_var = rctx.spec_var_stream.next();
 
        log!(cu.logger(), "Native branch spec var is {:?}", native_spec_var);
 
        let mut branching_native = BranchingNative { branches: Default::default() };
 
        'native_branches: for ((native_branch, index), branch_spec_val) in
 
            comm.native_batches.drain(..).zip(0..).zip(SpecVal::iter_domain())
 
        {
 
            let NativeBatch { to_get, to_put } = native_branch;
 
            let predicate = {
 
                let mut predicate = Predicate::default();
 
                // all firing ports have SpecVal::FIRING
 
                let firing_iter = to_get.iter().chain(to_put.keys()).copied();
 

	
 
                log!(
 
                    cu.logger(),
 
                    "New native with firing ports {:?}",
 
                    firing_iter.clone().collect::<Vec<_>>()
 
                );
 
                let firing_ports: HashSet<PortId> = firing_iter.clone().collect();
 
                for port in firing_iter {
 
                    let var = cu.inner.current_state.spec_var_for(port);
 
                    let var = cu.current_state.spec_var_for(port);
 
                    predicate.assigned.insert(var, SpecVal::FIRING);
 
                }
 
                // all silent ports have SpecVal::SILENT
 
                for (port, port_info) in cu.inner.current_state.port_info.iter() {
 
                    if port_info.owner != cu.inner.native_component_id {
 
                for (port, port_info) in cu.current_state.port_info.iter() {
 
                    if port_info.owner != cu.native_component_id {
 
                        // not my port
 
                        continue;
 
                    }
 
                    if firing_ports.contains(port) {
 
                        // this one is FIRING
 
                        continue;
 
                    }
 
                    let var = cu.inner.current_state.spec_var_for(*port);
 
                    let var = cu.current_state.spec_var_for(*port);
 
                    if let Some(SpecVal::FIRING) = predicate.assigned.insert(var, SpecVal::SILENT) {
 
                        log!(cu.logger(), "Native branch index={} contains internal inconsistency wrt. {:?}. Skipping", index, var);
 
                        continue 'native_branches;
 
                    }
 
                }
 
                // this branch is consistent. distinguish it with a unique var:val mapping and proceed
 
                predicate.inserted(native_spec_var, branch_spec_val)
 
            };
 
            log!(cu.logger(), "Native branch index={:?} has consistent {:?}", index, &predicate);
 
            // send all outgoing messages (by buffering them)
 
            for (putter, payload) in to_put {
 
                let msg = SendPayloadMsg { predicate: predicate.clone(), payload };
 
                log!(
 
                    cu.logger(),
 
                    "Native branch {} sending msg {:?} with putter {:?}",
 
                    index,
 
                    &msg,
 
                    putter
 
                );
 
                // sanity check
 
                assert_eq!(Putter, cu.inner.current_state.port_info.get(&putter).unwrap().polarity);
 
                assert_eq!(Putter, cu.current_state.port_info.get(&putter).unwrap().polarity);
 
                rctx.putter_push(cu, putter, msg);
 
            }
 
            let branch = NativeBranch { index, gotten: Default::default(), to_get };
 
            if branch.is_ended() {
 
                log!(
 
                    cu.logger(),
 
                    "Native submitting solution for batch {} with {:?}",
 
                    index,
 
                    &predicate
 
                );
 
                rctx.solution_storage.submit_and_digest_subtree_solution(
 
                    cu,
 
                    SubtreeId::LocalComponent(cu.inner.native_component_id),
 
                    SubtreeId::LocalComponent(cu.native_component_id),
 
                    predicate.clone(),
 
                );
 
            }
 
            if let Some(_) = branching_native.branches.insert(predicate, branch) {
 
                // thanks to the native_spec_var, each batch has a distinct predicate
 
                unreachable!()
 
            }
 
        }
 
        // restore the invariant: !native_batches.is_empty()
 
        comm.native_batches.push(Default::default());
 
        // Call to another big method; keep running this round until a distributed decision is reached
 
        log!(cu.logger(), "Searching for decision...");
 
        log!(@BENCH, cu.logger(), "");
 
        let decision = Self::sync_reach_decision(
 
            cu,
 
            comm,
 
            &mut branching_native,
 
            &mut branching_proto_components,
 
            &mut rctx,
 
        )?;
 
        log!(@MARK, cu.logger(), "got decision!");
 
        log!(cu.logger(), "Committing to decision {:?}!", &decision);
 
        log!(@BENCH, cu.logger(), "");
 
        comm.endpoint_manager.udp_endpoints_round_end(&mut *cu.logger(), &decision)?;
 

	
 
        // propagate the decision to children
 
        let msg = Msg::CommMsg(CommMsg {
 
            round_index: comm.round_index,
 
            contents: CommMsgContents::CommCtrl(CommCtrlMsg::Announce {
 
                decision: decision.clone(),
 
            }),
 
        });
 
        log!(
 
            cu.logger(),
 
            "Announcing decision {:?} through child endpoints {:?}",
 
            &msg,
 
            &comm.neighborhood.children
 
        );
 
        log!(@MARK, cu.logger(), "forwarding decision!");
 
        for &child in comm.neighborhood.children.iter() {
 
            comm.endpoint_manager.send_to_comms(child, &msg)?;
 
        }
 
        let ret = match decision {
 
            Decision::Failure => {
 
                // dropping {branching_proto_components, branching_native}
 
                log!(cu.inner.logger, "Failure with {:#?}", &rctx.solution_storage);
 
                log!(cu.logger, "Failure with {:#?}", &rctx.solution_storage);
 
                Err(Se::RoundFailure)
 
            }
 
            Decision::Success(predicate) => {
 
                // commit changes to component states
 
                cu.proto_components.clear();
 
                cu.proto_components.extend(
 
                    // consume branching proto components
 
                    branching_proto_components
 
                        .into_iter()
 
                        .map(|(id, bpc)| (id, bpc.collapse_with(&predicate))),
 
                );
 
                // commit changes to ports and id_manager
 
                cu.inner.current_state = rctx.current_state;
 
                cu.current_state = rctx.current_state;
 
                log!(
 
                    cu.inner.logger,
 
                    cu.logger,
 
                    "End round with (updated) component states {:?}",
 
                    cu.proto_components.keys()
 
                );
 
                // consume native
 
                Ok(Some(branching_native.collapse_with(&mut *cu.logger(), &predicate)))
 
            }
 
        };
 
        log!(cu.logger(), "Sync round ending! Cleaning up");
 
        log!(@BENCH, cu.logger(), "");
 
        ret
 
    }
 

	
 
    fn sync_reach_decision(
 
        cu: &mut impl CuUndecided,
 
        comm: &mut ConnectorCommunication,
 
        branching_native: &mut BranchingNative,
 
        branching_proto_components: &mut HashMap<ComponentId, BranchingProtoComponent>,
 
        rctx: &mut RoundCtx,
 
    ) -> Result<Decision, UnrecoverableSyncError> {
 
        log!(@MARK, cu.logger(), "decide start");
 
        let mut already_requested_failure = false;
 
        if branching_native.branches.is_empty() {
 
            log!(cu.logger(), "Native starts with no branches! Failure!");
 
            match comm.neighborhood.parent {
 
                Some(parent) => {
 
                    if already_requested_failure.replace_with_true() {
 
                        Self::request_failure(cu, comm, parent)?
 
                    } else {
 
                        log!(cu.logger(), "Already requested failure");
 
                    }
 
                }
 
                None => {
 
                    log!(cu.logger(), "No parent. Deciding on failure");
 
                    return Ok(Decision::Failure);
 
                }
 
            }
 
        }
 
        let mut pcb_temps_owner = <[HashMap<Predicate, ProtoComponentBranch>; 3]>::default();
 
        let mut pcb_temps = MapTempsGuard(&mut pcb_temps_owner);
 
        let mut bn_temp_owner = <HashMap<Predicate, NativeBranch>>::default();
 

	
 
        // run all proto components to their sync blocker
 
        log!(
 
            cu.logger(),
 
            "Running all {} proto components to their sync blocker...",
 
            branching_proto_components.len()
 
        );
 
        for (&proto_component_id, proto_component) in branching_proto_components.iter_mut() {
 
            let BranchingProtoComponent { branches } = proto_component;
 
            // must reborrow to constrain the lifetime of pcb_temps to inside the loop
 
            let (swap, pcb_temps) = pcb_temps.reborrow().split_first_mut();
 
            let (blocked, _pcb_temps) = pcb_temps.split_first_mut();
 
            // initially, no components have .ended==true
 
            // drain from branches --> blocked
 
            let cd = CyclicDrainer::new(branches, swap.0, blocked.0);
 
            BranchingProtoComponent::drain_branches_to_blocked(cd, cu, rctx, proto_component_id)?;
 
            // swap the blocked branches back
 
            std::mem::swap(blocked.0, branches);
 
            if branches.is_empty() {
 
                log!(cu.logger(), "{:?} has become inconsistent!", proto_component_id);
 
                if let Some(parent) = comm.neighborhood.parent {
 
                    if already_requested_failure.replace_with_true() {
 
                        Self::request_failure(cu, comm, parent)?
 
                    } else {
 
                        log!(cu.logger(), "Already requested failure");
 
                    }
 
                } else {
 
                    log!(cu.logger(), "As the leader, deciding on timeout");
 
                    return Ok(Decision::Failure);
 
                }
 
            }
 
        }
 
        log!(cu.logger(), "All proto components are blocked");
 

	
 
        log!(cu.logger(), "Entering decision loop...");
 
        comm.endpoint_manager.undelay_all();
 
        'undecided: loop {
 
            // drain payloads_to_get, sending them through endpoints / feeding them to components
 
            log!(cu.logger(), "Decision loop! have {} messages to recv", rctx.payload_inbox.len());
 
            while let Some((getter, send_payload_msg)) = rctx.getter_pop() {
 
                log!(@MARK, cu.logger(), "handling payload msg for getter {:?} of {:?}", getter, &send_payload_msg);
 
                let getter_info = rctx.current_state.port_info.get(&getter).unwrap();
 
                let cid = getter_info.owner;
 
                assert_eq!(Getter, getter_info.polarity);
 
                log!(
 
                    cu.logger(),
 
                    "Routing msg {:?} to {:?} via {:?}",
 
                    &send_payload_msg,
 
                    getter,
 
                    &getter_info.route
 
                );
 
                match getter_info.route {
 
                    Route::UdpEndpoint { index } => {
 
                        let udp_endpoint_ext =
 
                            &mut comm.endpoint_manager.udp_endpoint_store.endpoint_exts[index];
 
                        let SendPayloadMsg { predicate, payload } = send_payload_msg;
 
                        log!(cu.logger(), "Delivering to udp endpoint index={}", index);
 
                        udp_endpoint_ext.outgoing_payloads.insert(predicate, payload);
 
                    }
 
                    Route::NetEndpoint { index } => {
 
                        log!(@MARK, cu.logger(), "sending payload");
 
                        let msg = Msg::CommMsg(CommMsg {
 
                            round_index: comm.round_index,
 
                            contents: CommMsgContents::SendPayload(send_payload_msg),
 
                        });
 
                        comm.endpoint_manager.send_to_comms(index, &msg)?;
 
                    }
 
                    Route::LocalComponent if cid == cu.native_component_id() => branching_native
 
                        .feed_msg(
 
                            cu,
 
                            rctx,
 
                            getter,
 
                            &send_payload_msg,
 
                            MapTempGuard::new(&mut bn_temp_owner),
 
                        ),
 
                    Route::LocalComponent => {
 
                        if let Some(branching_component) = branching_proto_components.get_mut(&cid)
 
                        {
 
                            branching_component.feed_msg(
 
                                cu,
 
                                rctx,
 
                                cid,
 
                                getter,
 
                                &send_payload_msg,
 
                                pcb_temps.reborrow(),
 
                            )?;
 
                            if branching_component.branches.is_empty() {
 
                                log!(cu.logger(), "{:?} has become inconsistent!", cid);
 
                                if let Some(parent) = comm.neighborhood.parent {
 
                                    if already_requested_failure.replace_with_true() {
 
                                        Self::request_failure(cu, comm, parent)?
 
                                    } else {
 
                                        log!(cu.logger(), "Already requested failure");
 
                                    }
 
                                } else {
 
                                    log!(cu.logger(), "As the leader, deciding on timeout");
 
                                    return Ok(Decision::Failure);
 
                                }
 
                            }
 
                        } else {
 
                            log!(
 
                                cu.logger(),
 
                                "Delivery to getter {:?} msg {:?} failed because {:?} isn't here",
 
                                getter,
 
                                &send_payload_msg,
 
                                cid
 
                            );
 
                        }
 
                    }
 
                }
 
            }
 

	
 
            // check if we have a solution yet
 
            log!(cu.logger(), "Check if we have any local decisions...");
 
            for solution in rctx.solution_storage.iter_new_local_make_old() {
 
                log!(cu.logger(), "New local decision with solution {:?}...", &solution);
 
                log!(@MARK, cu.logger(), "local solution");
 
                match comm.neighborhood.parent {
 
                    Some(parent) => {
 
                        log!(cu.logger(), "Forwarding to my parent {:?}", parent);
 
                        let suggestion = Decision::Success(solution);
 
                        let msg = Msg::CommMsg(CommMsg {
 
                            round_index: comm.round_index,
 
                            contents: CommMsgContents::CommCtrl(CommCtrlMsg::Suggest {
 
                                suggestion,
 
                            }),
 
                        });
 
                        comm.endpoint_manager.send_to_comms(parent, &msg)?;
 
                    }
 
                    None => {
 
                        log!(cu.logger(), "No parent. Deciding on solution {:?}", &solution);
 
                        return Ok(Decision::Success(solution));
 
                    }
 
                }
 
            }
 

	
 
            // stuck! make progress by receiving a msg
 
            // try recv messages arriving through endpoints
 
            log!(cu.logger(), "No decision yet. Let's recv an endpoint msg...");
 
            {
 
                let (net_index, comm_ctrl_msg): (usize, CommCtrlMsg) =
 
                    match comm.endpoint_manager.try_recv_any_comms(cu, rctx, comm.round_index)? {
 
                        CommRecvOk::NewControlMsg { net_index, msg } => (net_index, msg),
 
                        CommRecvOk::NewPayloadMsgs => continue 'undecided,
 
                        CommRecvOk::TimeoutWithoutNew => {
 
                            log!(cu.logger(), "Reached user-defined deadling without decision...");
 
                            if let Some(parent) = comm.neighborhood.parent {
 
                                if already_requested_failure.replace_with_true() {
 
                                    Self::request_failure(cu, comm, parent)?
 
                                } else {
 
                                    log!(cu.logger(), "Already requested failure");
 
                                }
src/runtime/endpoints.rs
Show inline comments
 
use super::*;
 

	
 
struct MonitoredReader<R: Read> {
 
    bytes: usize,
 
    r: R,
 
}
 
enum PollAndPopulateError {
 
    PollFailed,
 
    Timeout,
 
}
 
struct TryRecvAnyNetError {
 
    error: NetEndpointError,
 
    index: usize,
 
}
 
/////////////////////
 
impl NetEndpoint {
 
    fn bincode_opts() -> impl bincode::config::Options {
 
        bincode::config::DefaultOptions::default()
 
    }
 
    pub(super) fn try_recv<T: serde::de::DeserializeOwned>(
 
        &mut self,
 
        logger: &mut dyn Logger,
 
    ) -> Result<Option<T>, NetEndpointError> {
 
        use NetEndpointError as Nee;
 
        // populate inbox as much as possible
 
        let before_len = self.inbox.len();
 
        'read_loop: loop {
 
            let res = self.stream.read_to_end(&mut self.inbox);
 
            match res {
 
                Err(e) if would_block(&e) => break 'read_loop,
 
                Err(e) if err_would_block(&e) => break 'read_loop,
 
                Ok(0) => break 'read_loop,
 
                Ok(_) => (),
 
                Err(_e) => return Err(Nee::BrokenNetEndpoint),
 
            }
 
        }
 
        log!(
 
            @ENDPT,
 
            logger,
 
            "Inbox bytes [{:x?}| {:x?}]",
 
            DenseDebugHex(&self.inbox[..before_len]),
 
            DenseDebugHex(&self.inbox[before_len..]),
 
        );
 
        let mut monitored = MonitoredReader::from(&self.inbox[..]);
 
        use bincode::config::Options;
 
        match Self::bincode_opts().deserialize_from(&mut monitored) {
 
            Ok(msg) => {
 
                let msg_size = monitored.bytes_read();
 
                self.inbox.drain(0..(msg_size.try_into().unwrap()));
 
                log!(
 
                    @ENDPT,
 
                    logger,
 
                    "Yielding msg. Inbox len {}-{}=={}: [{:?}]",
 
                    self.inbox.len() + msg_size,
 
                    msg_size,
 
                    self.inbox.len(),
 
                    DenseDebugHex(&self.inbox[..]),
 
                );
 
                Ok(Some(msg))
 
            }
 
            Err(e) => match *e {
 
                bincode::ErrorKind::Io(k) if k.kind() == std::io::ErrorKind::UnexpectedEof => {
 
                    Ok(None)
 
                }
 
                _ => Err(Nee::MalformedMessage),
 
            },
 
        }
 
    }
 
    pub(super) fn send<T: serde::ser::Serialize>(
 
        &mut self,
 
        msg: &T,
 
    ) -> Result<(), NetEndpointError> {
 
        use bincode::config::Options;
 
        use NetEndpointError as Nee;
 
        Self::bincode_opts()
 
            .serialize_into(&mut self.stream, msg)
 
            .map_err(|_| Nee::BrokenNetEndpoint)?;
 
        let _ = self.stream.flush();
 
        Ok(())
 
    }
 
}
 

	
 
impl EndpointManager {
 
    pub(super) fn index_iter(&self) -> Range<usize> {
 
        0..self.num_net_endpoints()
 
    }
 
    pub(super) fn num_net_endpoints(&self) -> usize {
 
        self.net_endpoint_store.endpoint_exts.len()
 
    }
 
    pub(super) fn send_to_comms(
 
        &mut self,
 
        index: usize,
 
        msg: &Msg,
 
    ) -> Result<(), UnrecoverableSyncError> {
 
        use UnrecoverableSyncError as Use;
 
        let net_endpoint = &mut self.net_endpoint_store.endpoint_exts[index].net_endpoint;
 
        net_endpoint.send(msg).map_err(|_| Use::BrokenNetEndpoint { index })
 
    }
 
    pub(super) fn send_to_setup(&mut self, index: usize, msg: &Msg) -> Result<(), ConnectError> {
 
        let net_endpoint = &mut self.net_endpoint_store.endpoint_exts[index].net_endpoint;
 
        net_endpoint.send(msg).map_err(|err| {
 
            ConnectError::NetEndpointSetupError(net_endpoint.stream.local_addr().unwrap(), err)
 
        })
 
    }
 

	
 
    /// Receive the first message of any kind at all.
 
    /// Why not return SetupMsg? Because often this message will be forwarded to several others,
 
    /// and by returning a Msg, it can be serialized in-place (NetEndpoints allow the sending of Msg types!)
 
    pub(super) fn try_recv_any_setup(
 
        &mut self,
 
        logger: &mut dyn Logger,
 
        deadline: &Option<Instant>,
 
    ) -> Result<(usize, Msg), ConnectError> {
 
        ///////////////////////////////////////////
 
        fn map_trane(
 
            trane: TryRecvAnyNetError,
 
            net_endpoint_store: &EndpointStore<NetEndpointExt>,
 
        ) -> ConnectError {
 
            ConnectError::NetEndpointSetupError(
 
                net_endpoint_store.endpoint_exts[trane.index]
 
                    .net_endpoint
 
                    .stream
 
                    .local_addr()
 
                    .unwrap(), // stream must already be connected
 
                trane.error,
 
            )
 
        }
 
        ///////////////////////////////////////////
 
        // try yield undelayed net message
 
        if let Some(tup) = self.undelayed_messages.pop() {
 
            log!(@ENDPT, logger, "RECV undelayed_msg {:?}", &tup);
 
            return Ok(tup);
 
        }
 
        loop {
 
            // try recv from some polled undrained NET endpoint
 
            if let Some(tup) = self
 
                .try_recv_undrained_net(logger)
 
                .map_err(|trane| map_trane(trane, &self.net_endpoint_store))?
 
            {
 
                return Ok(tup);
 
            }
 
            // poll if time remains
 
            self.poll_and_populate(logger, deadline)?;
 
        }
 
    }
 

	
 
    // drops all Setup messages,
 
    // buffers all future round messages,
 
    // drops all previous round messages,
 
    // enqueues all current round SendPayload messages using rctx.getter_push
 
    // returns the first comm_ctrl_msg encountered
 
    // only polls until SOME message is enqueued
 
    pub(super) fn try_recv_any_comms(
 
        &mut self,
 
        cu: &mut impl CuUndecided,
 
        rctx: &mut RoundCtx,
 
        round_index: usize,
 
    ) -> Result<CommRecvOk, UnrecoverableSyncError> {
 
        ///////////////////////////////////////////
 
        impl EndpointManager {
 
            fn handle_msg(
 
                &mut self,
 
                cu: &mut impl CuUndecided,
 
                rctx: &mut RoundCtx,
 
                net_index: usize,
 
                msg: Msg,
 
                round_index: usize,
 
                some_message_enqueued: &mut bool,
 
            ) -> Option<(usize, CommCtrlMsg)> {
 
                let comm_msg_contents = match msg {
 
                    Msg::SetupMsg(..) => return None,
 
                    Msg::CommMsg(comm_msg) => match comm_msg.round_index.cmp(&round_index) {
 
                        Ordering::Equal => comm_msg.contents,
 
                        Ordering::Less => {
 
                            log!(
 
                                cu.logger(),
 
                                "We are in round {}, but msg is for round {}. Discard",
 
                                comm_msg.round_index,
 
                                round_index,
 
                            );
 
                            return None;
 
                        }
 
                        Ordering::Greater => {
 
                            log!(
 
                                cu.logger(),
 
                                "We are in round {}, but msg is for round {}. Buffer",
 
                                comm_msg.round_index,
 
                                round_index,
 
                            );
 
                            self.delayed_messages.push((net_index, Msg::CommMsg(comm_msg)));
 
                            return None;
 
                        }
 
                    },
 
                };
 
                match comm_msg_contents {
 
                    CommMsgContents::CommCtrl(comm_ctrl_msg) => Some((net_index, comm_ctrl_msg)),
 
                    CommMsgContents::SendPayload(send_payload_msg) => {
 
                        let getter =
 
                            self.net_endpoint_store.endpoint_exts[net_index].getter_for_incoming;
 
                        rctx.getter_push(getter, send_payload_msg);
 
                        *some_message_enqueued = true;
 
                        None
 
                    }
 
                }
 
            }
 
        }
 
        use {PollAndPopulateError as Pape, UnrecoverableSyncError as Use};
 
        ///////////////////////////////////////////
 
        let mut some_message_enqueued = false;
 
        // try yield undelayed net message
 
        while let Some((net_index, msg)) = self.undelayed_messages.pop() {
 
            if let Some((net_index, msg)) =
 
                self.handle_msg(cu, rctx, net_index, msg, round_index, &mut some_message_enqueued)
 
            {
 
                return Ok(CommRecvOk::NewControlMsg { net_index, msg });
 
            }
 
        }
 
        loop {
 
            // try receive a net message
 
            while let Some((net_index, msg)) = self.try_recv_undrained_net(cu.logger())? {
 
                if let Some((net_index, msg)) = self.handle_msg(
 
                    cu,
 
                    rctx,
src/runtime/mod.rs
Show inline comments
 
/// cbindgen:ignore
 
mod communication;
 
/// cbindgen:ignore
 
mod endpoints;
 
pub mod error;
 
/// cbindgen:ignore
 
mod logging;
 
/// cbindgen:ignore
 
mod setup;
 

	
 
#[cfg(test)]
 
mod tests;
 

	
 
use crate::common::*;
 
use error::*;
 
use mio::net::UdpSocket;
 

	
 
/// Each Connector structure is the interface between the user's application and a communication session,
 
/// The interface between the user's application and a communication session,
 
/// in which the application plays the part of a (native) component. This structure provides the application
 
/// with functionality available to all components: the ability to add new channels (port pairs), and to
 
/// instantiate new components whose definitions are defined in the connector's configured protocol
 
/// description. Native components have the additional ability to add `dangling' ports backed by local/remote
 
/// IP addresses, to be coupled with a counterpart once the connector's setup is completed by `connect`.
 
/// This allows sets of applications to cooperate in constructing shared sessions that span the network.
 
#[derive(Debug)]
 
pub struct Connector {
 
    unphased: ConnectorUnphased,
 
    phased: ConnectorPhased,
 
}
 

	
 
/// Characterizes a type which can write lines of logging text.
 
/// The implementations provided in the `logging` module are likely to be sufficient,
 
/// but for added flexibility, users are able to implement their own loggers for use
 
/// by connectors.
 
pub trait Logger: Debug + Send + Sync {
 
    fn line_writer(&mut self) -> Option<&mut dyn std::io::Write>;
 
}
 

	
 
/// A logger that appends the logged strings to a growing byte buffer
 
#[derive(Debug)]
 
pub struct VecLogger(ConnectorId, Vec<u8>);
 

	
 
/// A trivial logger that always returns None, such that no logging information is ever written.
 
#[derive(Debug)]
 
pub struct DummyLogger;
 

	
 
/// A logger that writes the logged lines to a given file.
 
#[derive(Debug)]
 
pub struct FileLogger(ConnectorId, std::fs::File);
 
#[derive(Debug, Clone)]
 
struct CurrentState {
 
    port_info: HashMap<PortId, PortInfo>,
 
    id_manager: IdManager,
 
}
 

	
 
// Interface between protocol state and the connector runtime BEFORE all components
 
// ave begun their branching speculation. See ComponentState::nonsync_run.
 
pub(crate) struct NonsyncProtoContext<'a> {
 
    current_state: &'a mut CurrentState,
 
    logger: &'a mut dyn Logger,
 
    // cu_inner: &'a mut ConnectorUnphasedInner, // persists between rounds
 
    unrun_components: &'a mut Vec<(ComponentId, ComponentState)>, // lives for Nonsync phase
 
    proto_component_id: ComponentId,                              // KEY in id->component map
 
}
 

	
 
// Interface between protocol state and the connector runtime AFTER all components
 
// have begun their branching speculation. See ComponentState::sync_run.
 
pub(crate) struct SyncProtoContext<'a> {
 
    rctx: &'a RoundCtx,
 
    branch_inner: &'a mut ProtoComponentBranchInner, // sub-structure of component branch
 
    predicate: &'a Predicate,                        // KEY in pred->branch map
 
}
 

	
 
// The data coupled with a particular protocol component branch, but crucially omitting
 
// the `ComponentState` such that this may be passed by reference to the state with separate
 
// access control.
 
#[derive(Default, Debug, Clone)]
 
struct ProtoComponentBranchInner {
 
    untaken_choice: Option<u16>,
 
    did_put_or_get: HashSet<PortId>,
 
    inbox: HashMap<PortId, Payload>,
 
}
 

	
 
// A speculative variable that lives for the duration of the synchronous round.
 
// Each is assigned a value in domain `SpecVal`.
 
#[derive(
 
    Copy, Clone, Eq, PartialEq, Ord, Hash, PartialOrd, serde::Serialize, serde::Deserialize,
 
)]
 
struct SpecVar(PortId);
 

	
 
// The codomain of SpecVal. Has two associated constants for values FIRING and SILENT,
 
// but may also enumerate many more values to facilitate finer-grained nondeterministic branching.
 
#[derive(
 
    Copy, Clone, Eq, PartialEq, Ord, Hash, PartialOrd, serde::Serialize, serde::Deserialize,
 
)]
 
struct SpecVal(u16);
 

	
 
// Data associated with a successful synchronous round, retained afterwards such that the
 
// native component can freely reflect on how it went, reading the messages received at their
 
// inputs, and reflecting on which of their connector's synchronous batches succeeded.
 
#[derive(Debug)]
 
struct RoundOk {
 
    batch_index: usize,
 
    gotten: HashMap<PortId, Payload>,
 
}
 

	
 
// Implementation of a set in terms of a vector (optimized for reading, not writing)
 
#[derive(Default)]
 
struct VecSet<T: std::cmp::Ord> {
 
    // invariant: ordered, deduplicated
 
    vec: Vec<T>,
 
}
 

	
 
// Allows a connector to remember how to forward payloads towards the component that
 
// owns their destination port. `LocalComponent` corresponds with messages for components
 
// managed by the connector itself (hinting for it to look it up in a local structure),
 
// whereas the other variants direct the connector to forward the messages over the network.
 
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash, serde::Serialize, serde::Deserialize)]
 
enum Route {
 
    LocalComponent,
 
    NetEndpoint { index: usize },
 
    UdpEndpoint { index: usize },
 
}
 
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash, serde::Serialize, serde::Deserialize)]
 
enum SubtreeId {
 
    LocalComponent(ComponentId),
 
    NetEndpoint { index: usize },
 
}
 

	
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
struct MyPortInfo {
 
    polarity: Polarity,
 
    port: PortId,
 
    owner: ComponentId,
 
}
 
#[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 
enum Decision {
 
    Failure,
 
    Success(Predicate),
 
}
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
enum Msg {
 
    SetupMsg(SetupMsg),
 
    CommMsg(CommMsg),
 
}
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
enum SetupMsg {
 
    MyPortInfo(MyPortInfo),
 
    LeaderWave { wave_leader: ConnectorId },
 
    LeaderAnnounce { tree_leader: ConnectorId },
 
    YouAreMyParent,
 
    SessionGather { unoptimized_map: HashMap<ConnectorId, SessionInfo> },
 
    SessionScatter { optimized_map: HashMap<ConnectorId, SessionInfo> },
 
}
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
struct SessionInfo {
 
    serde_proto_description: SerdeProtocolDescription,
 
    port_info: HashMap<PortId, PortInfo>,
 
    endpoint_incoming_to_getter: Vec<PortId>,
 
    proto_components: HashMap<ComponentId, ComponentState>,
 
}
 
#[derive(Debug, Clone)]
 
struct SerdeProtocolDescription(Arc<ProtocolDescription>);
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
struct CommMsg {
 
    round_index: usize,
 
    contents: CommMsgContents,
 
}
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
enum CommMsgContents {
 
    SendPayload(SendPayloadMsg),
 
    CommCtrl(CommCtrlMsg),
 
}
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
enum CommCtrlMsg {
 
    Suggest { suggestion: Decision }, // SINKWARD
 
    Announce { decision: Decision },  // SINKAWAYS
 
}
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
struct SendPayloadMsg {
 
    predicate: Predicate,
 
    payload: Payload,
 
}
 
#[derive(Debug, PartialEq)]
 
enum AssignmentUnionResult {
 
    FormerNotLatter,
 
    LatterNotFormer,
 
    Equivalent,
 
    New(Predicate),
 
    Nonexistant,
 
}
 
struct NetEndpoint {
 
    inbox: Vec<u8>,
 
    stream: TcpStream,
 
}
 
#[derive(Debug, Clone)]
 
struct NetEndpointSetup {
 
    getter_for_incoming: PortId,
 
    sock_addr: SocketAddr,
 
    endpoint_polarity: EndpointPolarity,
 
}
 

	
 
#[derive(Debug, Clone)]
 
struct UdpEndpointSetup {
 
    getter_for_incoming: PortId,
 
    local_addr: SocketAddr,
 
    peer_addr: SocketAddr,
 
}
 
#[derive(Debug)]
 
struct NetEndpointExt {
 
    net_endpoint: NetEndpoint,
 
    getter_for_incoming: PortId,
 
}
 
#[derive(Debug)]
 
struct UdpEndpointExt {
 
    sock: UdpSocket, // already bound and connected
 
    received_this_round: bool,
 
    outgoing_payloads: HashMap<Predicate, Payload>,
 
    getter_for_incoming: PortId,
 
}
 
#[derive(Debug)]
 
struct Neighborhood {
 
    parent: Option<usize>,
 
    children: VecSet<usize>,
 
}
 
#[derive(Debug, Clone)]
 
struct IdManager {
 
    connector_id: ConnectorId,
 
    port_suffix_stream: U32Stream,
 
    component_suffix_stream: U32Stream,
 
}
 
struct UdpInBuffer {
 
    byte_vec: Vec<u8>,
 
}
 
#[derive(Debug)]
 
struct SpecVarStream {
 
    connector_id: ConnectorId,
 
    port_suffix_stream: U32Stream,
 
}
 
#[derive(Debug)]
 
struct EndpointManager {
 
    // invariants:
 
    // 1. net and udp endpoints are registered with poll. Poll token computed with TargetToken::into
 
    // 2. Events is empty
 
    poll: Poll,
 
    events: Events,
 
    delayed_messages: Vec<(usize, Msg)>,
 
    undelayed_messages: Vec<(usize, Msg)>,
 
    net_endpoint_store: EndpointStore<NetEndpointExt>,
 
    udp_endpoint_store: EndpointStore<UdpEndpointExt>,
 
    udp_in_buffer: UdpInBuffer,
 
}
 
#[derive(Debug)]
 
struct EndpointStore<T> {
 
    endpoint_exts: Vec<T>,
 
    polled_undrained: VecSet<usize>,
 
}
 
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
 
struct PortInfo {
 
    owner: ComponentId,
 
    peer: Option<PortId>,
 
    polarity: Polarity,
 
    route: Route,
 
}
 

	
 
#[derive(Debug, Clone)]
 
struct CurrentState {
 
    port_info: HashMap<PortId, PortInfo>,
 
    id_manager: IdManager,
 
}
 

	
 
// A component's setup-phase-specific data
 
#[derive(Debug)]
 
struct ConnectorCommunication {
 
    round_index: usize,
 
    endpoint_manager: EndpointManager,
 
    neighborhood: Neighborhood,
 
    native_batches: Vec<NativeBatch>,
 
    round_result: Result<Option<RoundOk>, SyncError>,
 
}
 
#[derive(Debug)]
 
struct ConnectorUnphased {
 
    proto_description: Arc<ProtocolDescription>,
 
    proto_components: HashMap<ComponentId, ComponentState>,
 
    inner: ConnectorUnphasedInner,
 
}
 
#[derive(Debug)]
 
struct ConnectorUnphasedInner {
 
    logger: Box<dyn Logger>,
 
    current_state: CurrentState,
 
    native_component_id: ComponentId,
 
}
 
#[derive(Debug)]
 
struct ConnectorSetup {
 
    net_endpoint_setups: Vec<NetEndpointSetup>,
 
    udp_endpoint_setups: Vec<UdpEndpointSetup>,
 
}
 

	
 
// A connector's phase-specific data
 
#[derive(Debug)]
 
enum ConnectorPhased {
 
    Setup(Box<ConnectorSetup>),
 
    Communication(Box<ConnectorCommunication>),
 
}
 

	
 
// A connector's setup-phase-specific data
 
#[derive(Debug)]
 
struct ConnectorSetup {
 
    net_endpoint_setups: Vec<NetEndpointSetup>,
 
    udp_endpoint_setups: Vec<UdpEndpointSetup>,
 
}
 

	
 
#[derive(Default, Clone, Eq, PartialEq, Hash, serde::Serialize, serde::Deserialize)]
 
struct Predicate {
 
    assigned: BTreeMap<SpecVar, SpecVal>,
 
}
 

	
 
// Identifies a child of this connector in the _solution tree_.
 
// Each connector creates its own local solutions for the consensus procedure during `sync`,
 
// from the solutions of its children. Those children are either locally-managed components,
 
// (which are leaves in the solution tree), or other connectors reachable through the given
 
// network endpoint (which are internal nodes in the solution tree).
 
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash, serde::Serialize, serde::Deserialize)]
 
enum SubtreeId {
 
    LocalComponent(ComponentId),
 
    NetEndpoint { index: usize },
 
}
 

	
 
// An accumulation of the connector's knowledge of all (a) the local solutions its children
 
// in the solution tree have found, and (b) its own solutions derivable from those of its children.
 
// This structure starts off each round with an empty set, and accumulates solutions as they are found
 
// by local components, or received over the network in control messages.
 
// IMPORTANT: solutions, once found, don't go away until the end of the round. That is to
 
// say that these sets GROW until the round is over, and all solutions are reset.
 
#[derive(Debug)]
 
struct SolutionStorage {
 
    // invariant: old_local U new_local solutions are those that can be created from
 
    // the UNION of one element from each set in `subtree_solution`.
 
    // invariant is maintained by potentially populating new_local whenever subtree_solutions is populated.
 
    old_local: HashSet<Predicate>,
 
    new_local: HashSet<Predicate>,
 
    // this pair acts as SubtreeId -> HashSet<Predicate> which is friendlier to iteration
 
    subtree_solutions: Vec<HashSet<Predicate>>,
 
    subtree_id_to_index: HashMap<SubtreeId, usize>,
 
}
 

	
 
// Stores the transient data of a synchronous round.
 
// Some of it is for bookkeeping, and the rest is a temporary mirror of fields of
 
// `ConnectorUnphased`, such that any changes are safely contained within RoundCtx,
 
// and can be undone if the round fails.
 
struct RoundCtx {
 
    solution_storage: SolutionStorage,
 
    spec_var_stream: SpecVarStream,
 
    payload_inbox: Vec<(PortId, SendPayloadMsg)>,
 
    deadline: Option<Instant>,
 
    current_state: CurrentState,
 
}
 

	
 
// A trait intended to limit the access of the ConnectorUnphased structure
 
// such that we don't accidentally modify any important component/port data
 
// while the results of the round are undecided. Why? Any actions during Connector::sync
 
// are _speculative_ until the round is decided, and we need a safe way of rolling
 
// back any changes.
 
trait CuUndecided {
 
    fn logger(&mut self) -> &mut dyn Logger;
 
    fn proto_description(&self) -> &ProtocolDescription;
 
    fn native_component_id(&self) -> ComponentId;
 
    fn logger_and_protocol_description(&mut self) -> (&mut dyn Logger, &ProtocolDescription);
 
}
 

	
 
// Represents a set of synchronous port operations that the native component
 
// has described as an "option" for completing during the synchronous rounds.
 
// Operations contained here succeed together or not at all.
 
// A native with N=2+ batches are expressing an N-way nondeterministic choice
 
#[derive(Debug, Default)]
 
struct NativeBatch {
 
    // invariant: putters' and getters' polarities respected
 
    to_put: HashMap<PortId, Payload>,
 
    to_get: HashSet<PortId>,
 
}
 

	
 
// Parallels a mio::Token type, but more clearly communicates
 
// the way it identifies the evented structre it corresponds to.
 
// See runtime/setup for methods converting between TokenTarget and mio::Token
 
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 
enum TokenTarget {
 
    NetEndpoint { index: usize },
 
    UdpEndpoint { index: usize },
 
    Waker,
 
}
 

	
 
// Returned by the endpoint manager as a result of comm_recv, telling the connector what happened,
 
// such that it can know when to continue polling, and when to block.
 
enum CommRecvOk {
 
    TimeoutWithoutNew,
 
    NewPayloadMsgs,
 
    NewControlMsg { net_index: usize, msg: CommCtrlMsg },
 
}
 
////////////////
 
fn would_block(err: &std::io::Error) -> bool {
 
fn err_would_block(err: &std::io::Error) -> bool {
 
    err.kind() == std::io::ErrorKind::WouldBlock
 
}
 
impl TokenTarget {
 
    const HALFWAY_INDEX: usize = usize::MAX / 2;
 
    const MAX_INDEX: usize = usize::MAX;
 
    const WAKER_TOKEN: usize = Self::MAX_INDEX;
 
}
 
impl From<Token> for TokenTarget {
 
    fn from(Token(index): Token) -> Self {
 
        if index == Self::WAKER_TOKEN {
 
            TokenTarget::Waker
 
        } else if let Some(shifted) = index.checked_sub(Self::HALFWAY_INDEX) {
 
            TokenTarget::UdpEndpoint { index: shifted }
 
        } else {
 
            TokenTarget::NetEndpoint { index }
 
        }
 
    }
 
}
 
impl Into<Token> for TokenTarget {
 
    fn into(self) -> Token {
 
        match self {
 
            TokenTarget::Waker => Token(Self::WAKER_TOKEN),
 
            TokenTarget::UdpEndpoint { index } => Token(index + Self::HALFWAY_INDEX),
 
            TokenTarget::NetEndpoint { index } => Token(index),
 
        }
 
    }
 
}
 
impl<T: std::cmp::Ord> VecSet<T> {
 
    fn new(mut vec: Vec<T>) -> Self {
 
        vec.sort();
 
        vec.dedup();
 
        Self { vec }
 
    }
 
    fn contains(&self, element: &T) -> bool {
 
        self.vec.binary_search(element).is_ok()
 
    }
 
    fn insert(&mut self, element: T) -> bool {
 
        match self.vec.binary_search(&element) {
 
            Ok(_) => false,
 
            Err(index) => {
 
                self.vec.insert(index, element);
 
                true
 
            }
 
        }
 
    }
 
    fn iter(&self) -> std::slice::Iter<T> {
 
        self.vec.iter()
 
    }
 
    fn pop(&mut self) -> Option<T> {
 
        self.vec.pop()
 
    }
 
}
 
impl CurrentState {
 
    fn spec_var_for(&self, port: PortId) -> SpecVar {
 
        let info = self.port_info.get(&port).unwrap();
 
        SpecVar(match info.polarity {
 
            Getter => port,
 
            Putter => info.peer.unwrap(),
 
        })
 
    }
 
}
 
impl SpecVarStream {
 
    fn next(&mut self) -> SpecVar {
 
        let phantom_port: PortId =
 
            Id { connector_id: self.connector_id, u32_suffix: self.port_suffix_stream.next() }
 
                .into();
 
        SpecVar(phantom_port)
 
    }
 
}
 
impl IdManager {
 
    fn new(connector_id: ConnectorId) -> Self {
 
        Self {
 
            connector_id,
 
            port_suffix_stream: Default::default(),
 
            component_suffix_stream: Default::default(),
 
        }
 
    }
 
    fn new_spec_var_stream(&self) -> SpecVarStream {
 
        // Spec var stream starts where the current port_id stream ends, with gap of SKIP_N.
 
        // This gap is entirely unnecessary (i.e. 0 is fine)
 
        // It's purpose is only to make SpecVars easier to spot in logs.
 
        // E.g. spot the spec var: { v0_0, v1_2, v1_103 }
 
        const SKIP_N: u32 = 100;
 
        let port_suffix_stream = self.port_suffix_stream.clone().n_skipped(SKIP_N);
 
        SpecVarStream { connector_id: self.connector_id, port_suffix_stream }
 
    }
 
    fn new_port_id(&mut self) -> PortId {
 
        Id { connector_id: self.connector_id, u32_suffix: self.port_suffix_stream.next() }.into()
 
    }
 
    fn new_component_id(&mut self) -> ComponentId {
 
        Id { connector_id: self.connector_id, u32_suffix: self.component_suffix_stream.next() }
 
            .into()
 
    }
 
}
 
impl Drop for Connector {
 
    fn drop(&mut self) {
 
        log!(&mut *self.unphased.inner.logger, "Connector dropping. Goodbye!");
 
    }
 
}
 

	
 
fn duplicate_port(slice: &[PortId]) -> Option<PortId> {
 
    let mut vec = Vec::with_capacity(slice.len());
 
    for port in slice.iter() {
 
        match vec.binary_search(port) {
 
            Err(index) => vec.insert(index, *port),
 
            Ok(_) => return Some(*port),
 
        }
 
    }
 
    None
 
}
 
impl Connector {
 
    /// Generate a random connector identifier from the system's source of randomness.
 
    pub fn random_id() -> ConnectorId {
 
        type Bytes8 = [u8; std::mem::size_of::<ConnectorId>()];
 
        unsafe {
 
            let mut bytes = std::mem::MaybeUninit::<Bytes8>::uninit();
 
            // getrandom is the canonical crate for a small, secure rng
 
            getrandom::getrandom(&mut *bytes.as_mut_ptr()).unwrap();
 
            // safe! representations of all valid Byte8 values are valid ConnectorId values
 
            std::mem::transmute::<_, _>(bytes.assume_init())
 
        }
 
    }
 

	
 
    /// Returns true iff the connector is in connected state, i.e., it's setup phase is complete,
 
    /// and it is ready to participate in synchronous rounds of communication.
 
    pub fn is_connected(&self) -> bool {
 
        // If designed for Rust usage, connectors would be exposed as an enum type from the start.
 
        // consequently, this "phased" business would also include connector variants and this would
 
        // get a lot closer to the connector impl. itself.
 
        // Instead, the C-oriented implementation doesn't distinguish connector states as types,
 
        // and distinguish them as enum variants instead
 
        match self.phased {
 
            ConnectorPhased::Setup(..) => false,
 
            ConnectorPhased::Communication(..) => true,
 
        }
 
    }
 

	
 
    /// Enables the connector's current logger to be swapped out for another
 
    pub fn swap_logger(&mut self, mut new_logger: Box<dyn Logger>) -> Box<dyn Logger> {
 
        std::mem::swap(&mut self.unphased.inner.logger, &mut new_logger);
 
        std::mem::swap(&mut self.unphased.logger, &mut new_logger);
 
        new_logger
 
    }
 

	
 
    /// Access the connector's current logger
 
    pub fn get_logger(&mut self) -> &mut dyn Logger {
 
        &mut *self.unphased.inner.logger
 
        &mut *self.unphased.logger
 
    }
 

	
 
    /// Create a new synchronous channel, returning its ends as a pair of ports,
 
    /// with polarity output, input respectively. Available during either setup/communication phase.
 
    /// # Panics
 
    /// This function panics if the connector's (large) port id space is exhausted.
 
    pub fn new_port_pair(&mut self) -> [PortId; 2] {
 
        let cu = &mut self.unphased;
 
        // adds two new associated ports, related to each other, and exposed to the native
 
        let mut new_cid = || cu.inner.current_state.id_manager.new_port_id();
 
        let mut new_cid = || cu.current_state.id_manager.new_port_id();
 
        let [o, i] = [new_cid(), new_cid()];
 
        cu.inner.current_state.port_info.insert(
 
        cu.current_state.port_info.insert(
 
            o,
 
            PortInfo {
 
                route: Route::LocalComponent,
 
                peer: Some(i),
 
                owner: cu.inner.native_component_id,
 
                owner: cu.native_component_id,
 
                polarity: Putter,
 
            },
 
        );
 
        cu.inner.current_state.port_info.insert(
 
        cu.current_state.port_info.insert(
 
            i,
 
            PortInfo {
 
                route: Route::LocalComponent,
 
                peer: Some(o),
 
                owner: cu.inner.native_component_id,
 
                owner: cu.native_component_id,
 
                polarity: Getter,
 
            },
 
        );
 
        log!(cu.inner.logger, "Added port pair (out->in) {:?} -> {:?}", o, i);
 
        log!(cu.logger, "Added port pair (out->in) {:?} -> {:?}", o, i);
 
        [o, i]
 
    }
 

	
 
    /// Instantiates a new component for the connector runtime to manage, and passing
 
    /// the given set of ports from the interface of the native component, to that of the
 
    /// newly created component (passing their ownership).
 
    /// # Errors
 
    /// Error is returned if the moved ports are not owned by the native component,
 
    /// if the given component name is not defined in the connector's protocol,
 
    /// the given sequence of ports contains a duplicate port,
 
    /// or if the component is unfit for instantiation with the given port sequence.
 
    /// # Panics
 
    /// This function panics if the connector's (large) component id space is exhausted.
 
    pub fn add_component(
 
        &mut self,
 
        identifier: &[u8],
 
        ports: &[PortId],
 
    ) -> Result<(), AddComponentError> {
 
        // called by the USER. moves ports owned by the NATIVE
 
        use AddComponentError as Ace;
 
        // 1. check if this is OK
 
        if let Some(port) = duplicate_port(ports) {
 
            return Err(Ace::DuplicatePort(port));
 
        }
 
        let cu = &mut self.unphased;
 
        let expected_polarities = cu.proto_description.component_polarities(identifier)?;
 
        if expected_polarities.len() != ports.len() {
 
            return Err(Ace::WrongNumberOfParamaters { expected: expected_polarities.len() });
 
        }
 
        for (&expected_polarity, &port) in expected_polarities.iter().zip(ports.iter()) {
 
            let info = cu.inner.current_state.port_info.get(&port).ok_or(Ace::UnknownPort(port))?;
 
            if info.owner != cu.inner.native_component_id {
 
            let info = cu.current_state.port_info.get(&port).ok_or(Ace::UnknownPort(port))?;
 
            if info.owner != cu.native_component_id {
 
                return Err(Ace::UnknownPort(port));
 
            }
 
            if info.polarity != expected_polarity {
 
                return Err(Ace::WrongPortPolarity { port, expected_polarity });
 
            }
 
        }
 
        // 2. add new component
 
        let new_cid = cu.inner.current_state.id_manager.new_component_id();
 
        let new_cid = cu.current_state.id_manager.new_component_id();
 
        cu.proto_components
 
            .insert(new_cid, cu.proto_description.new_main_component(identifier, ports));
 
        // 3. update port ownership
 
        for port in ports.iter() {
 
            match cu.inner.current_state.port_info.get_mut(port) {
 
            match cu.current_state.port_info.get_mut(port) {
 
                Some(port_info) => port_info.owner = new_cid,
 
                None => unreachable!(),
 
            }
 
        }
 
        Ok(())
 
    }
 
}
 
impl Predicate {
 
    #[inline]
 
    pub fn singleton(k: SpecVar, v: SpecVal) -> Self {
 
        Self::default().inserted(k, v)
 
    }
 
    #[inline]
 
    pub fn inserted(mut self, k: SpecVar, v: SpecVal) -> Self {
 
        self.assigned.insert(k, v);
 
        self
 
    }
 

	
 
    pub fn assigns_subset(&self, maybe_superset: &Self) -> bool {
 
        for (var, val) in self.assigned.iter() {
 
            match maybe_superset.assigned.get(var) {
 
                Some(val2) if val2 == val => {}
 
                _ => return false, // var unmapped, or mapped differently
 
            }
 
        }
 
        true
 
    }
 

	
 
    // returns true IFF self.unify would return Equivalent OR FormerNotLatter
 
    // pub fn consistent_with(&self, other: &Self) -> bool {
 
    //     let [larger, smaller] =
 
    //         if self.assigned.len() > other.assigned.len() { [self, other] } else { [other, self] };
 

	
 
    //     for (var, val) in smaller.assigned.iter() {
 
    //         match larger.assigned.get(var) {
 
    //             Some(val2) if val2 != val => return false,
 
    //             _ => {}
 
    //         }
 
    //     }
 
    //     true
 
    // }
 

	
 
    /// Given self and other, two predicates, return the predicate whose
 
    /// assignments are the union of those of self and other.
 
    fn assignment_union(&self, other: &Self) -> AssignmentUnionResult {
 
        use AssignmentUnionResult as Aur;
 
        // iterators over assignments of both predicates. Rely on SORTED ordering of BTreeMap's keys.
 
        let [mut s_it, mut o_it] = [self.assigned.iter(), other.assigned.iter()];
 
        let [mut s, mut o] = [s_it.next(), o_it.next()];
 
        // lists of assignments in self but not other and vice versa.
 
        let [mut s_not_o, mut o_not_s] = [vec![], vec![]];
 
        loop {
 
            match [s, o] {
 
                [None, None] => break,
 
                [None, Some(x)] => {
 
                    o_not_s.push(x);
 
                    o_not_s.extend(o_it);
 
                    break;
 
                }
 
                [Some(x), None] => {
 
                    s_not_o.push(x);
 
                    s_not_o.extend(s_it);
 
                    break;
 
                }
 
                [Some((sid, sb)), Some((oid, ob))] => {
 
                    if sid < oid {
 
                        // o is missing this element
 
                        s_not_o.push((sid, sb));
 
                        s = s_it.next();
 
                    } else if sid > oid {
 
                        // s is missing this element
 
                        o_not_s.push((oid, ob));
 
                        o = o_it.next();
 
                    } else if sb != ob {
 
                        assert_eq!(sid, oid);
 
                        // both predicates assign the variable but differ on the value
 
                        return Aur::Nonexistant;
 
                    } else {
 
                        // both predicates assign the variable to the same value
 
                        s = s_it.next();
 
                        o = o_it.next();
 
                    }
 
                }
 
            }
 
        }
 
        // Observed zero inconsistencies. A unified predicate exists...
 
        match [s_not_o.is_empty(), o_not_s.is_empty()] {
 
            [true, true] => Aur::Equivalent,       // ... equivalent to both.
 
            [false, true] => Aur::FormerNotLatter, // ... equivalent to self.
 
            [true, false] => Aur::LatterNotFormer, // ... equivalent to other.
 
            [false, false] => {
 
                // ... which is the union of the predicates' assignments but
 
                //     is equivalent to neither self nor other.
 
                let mut new = self.clone();
 
                for (&id, &b) in o_not_s {
 
                    new.assigned.insert(id, b);
 
                }
 
                Aur::New(new)
 
            }
 
        }
 
    }
 
    pub(crate) fn union_with(&self, other: &Self) -> Option<Self> {
 
        let mut res = self.clone();
 
        for (&channel_id, &assignment_1) in other.assigned.iter() {
 
            match res.assigned.insert(channel_id, assignment_1) {
 
                Some(assignment_2) if assignment_1 != assignment_2 => return None,
 
                _ => {}
 
            }
 
        }
 
        Some(res)
 
    }
 
    pub(crate) fn query(&self, var: SpecVar) -> Option<SpecVal> {
 
        self.assigned.get(&var).copied()
 
    }
 
}
 
impl<T: Debug + std::cmp::Ord> Debug for VecSet<T> {
 
    fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
 
        f.debug_set().entries(self.vec.iter()).finish()
 
    }
 
}
 
impl Debug for Predicate {
 
    fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
 
        struct Assignment<'a>((&'a SpecVar, &'a SpecVal));
 
        impl Debug for Assignment<'_> {
 
            fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
 
                write!(f, "{:?}={:?}", (self.0).0, (self.0).1)
 
            }
 
        }
 
        f.debug_set().entries(self.assigned.iter().map(Assignment)).finish()
 
    }
 
}
 
impl serde::Serialize for SerdeProtocolDescription {
 
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
 
    where
 
        S: serde::Serializer,
 
    {
 
        let inner: &ProtocolDescription = &self.0;
 
        inner.serialize(serializer)
 
    }
 
}
 
impl<'de> serde::Deserialize<'de> for SerdeProtocolDescription {
 
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
 
    where
 
        D: serde::Deserializer<'de>,
 
    {
 
        let inner: ProtocolDescription = ProtocolDescription::deserialize(deserializer)?;
 
        Ok(Self(Arc::new(inner)))
 
    }
 
}
 
impl IdParts for SpecVar {
 
    fn id_parts(self) -> (ConnectorId, U32Suffix) {
 
        self.0.id_parts()
 
    }
 
}
 
impl Debug for SpecVar {
 
    fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
 
        let (a, b) = self.id_parts();
 
        write!(f, "v{}_{}", a, b)
 
    }
 
}
 
impl SpecVal {
 
    const FIRING: Self = SpecVal(1);
 
    const SILENT: Self = SpecVal(0);
 
    fn is_firing(self) -> bool {
 
        self == Self::FIRING
 
        // all else treated as SILENT
 
    }
 
    fn iter_domain() -> impl Iterator<Item = Self> {
 
        (0..).map(SpecVal)
 
    }
 
}
 
impl Debug for SpecVal {
 
    fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
 
        self.0.fmt(f)
 
    }
 
}
 
impl Default for UdpInBuffer {
 
    fn default() -> Self {
 
        let mut byte_vec = Vec::with_capacity(Self::CAPACITY);
 
        unsafe {
 
            // safe! this vector is guaranteed to have sufficient capacity
 
            byte_vec.set_len(Self::CAPACITY);
 
        }
 
        Self { byte_vec }
 
    }
 
}
 
impl UdpInBuffer {
 
    const CAPACITY: usize = u16::MAX as usize;
 
    fn as_mut_slice(&mut self) -> &mut [u8] {
 
        self.byte_vec.as_mut_slice()
 
    }
 
}
src/runtime/setup.rs
Show inline comments
 
use crate::common::*;
 
use crate::runtime::*;
 

	
 
impl TokenTarget {
 
    const HALFWAY_INDEX: usize = usize::MAX / 2;
 
    const MAX_INDEX: usize = usize::MAX;
 
    const WAKER_TOKEN: usize = Self::MAX_INDEX;
 
}
 
impl From<Token> for TokenTarget {
 
    fn from(Token(index): Token) -> Self {
 
        if index == Self::WAKER_TOKEN {
 
            TokenTarget::Waker
 
        } else if let Some(shifted) = index.checked_sub(Self::HALFWAY_INDEX) {
 
            TokenTarget::UdpEndpoint { index: shifted }
 
        } else {
 
            TokenTarget::NetEndpoint { index }
 
        }
 
    }
 
}
 
impl Into<Token> for TokenTarget {
 
    fn into(self) -> Token {
 
        match self {
 
            TokenTarget::Waker => Token(Self::WAKER_TOKEN),
 
            TokenTarget::UdpEndpoint { index } => Token(index + Self::HALFWAY_INDEX),
 
            TokenTarget::NetEndpoint { index } => Token(index),
 
        }
 
    }
 
}
 
impl Connector {
 
    /// Create a new connector structure with the given protocol description (via Arc to facilitate sharing).
 
    /// The resulting connector will start in the setup phase, and cannot be used for communication until the
 
    /// `connect` procedure completes.
 
    /// # Safety
 
    /// The correctness of the system's underlying distributed algorithms requires that no two
 
    /// connectors have the same ID. If the user does not know the identifiers of other connectors in the
 
    /// system, it is advised to guess it using Connector::random_id (relying on the exceptionally low probability of an error).
 
    /// Sessions with duplicate connector identifiers will not result in any memory unsafety, but cannot be guaranteed
 
    /// to preserve their configured protocols.
 
    /// Fortunately, in most realistic cases, the presence of duplicate connector identifiers will result in an
 
    /// error during `connect`, observed as a peer misbehaving.
 
    pub fn new(
 
        mut logger: Box<dyn Logger>,
 
        proto_description: Arc<ProtocolDescription>,
 
        connector_id: ConnectorId,
 
    ) -> Self {
 
        log!(&mut *logger, "Created with connector_id {:?}", connector_id);
 
        let mut id_manager = IdManager::new(connector_id);
 
        let native_component_id = id_manager.new_component_id();
 
        Self {
 
            unphased: ConnectorUnphased {
 
                proto_description,
 
                proto_components: Default::default(),
 
                inner: ConnectorUnphasedInner {
 
                    logger,
 
                    native_component_id,
 
                    current_state: CurrentState { id_manager, port_info: Default::default() },
 
                },
 
                logger,
 
                native_component_id,
 
                current_state: CurrentState { id_manager, port_info: Default::default() },
 
            },
 
            phased: ConnectorPhased::Setup(Box::new(ConnectorSetup {
 
                net_endpoint_setups: Default::default(),
 
                udp_endpoint_setups: Default::default(),
 
            })),
 
        }
 
    }
 
    /// Conceptually, this returning [p0, g1] is sugar for:
 
    /// 1. create port pair [p0, g0]
 
    /// 2. create port pair [p1, g1]
 
    /// 3. create udp component with interface of moved ports [p1, g0]
 
    /// 4. return [p0, g1]
 
    pub fn new_udp_mediator_component(
 
        &mut self,
 
        local_addr: SocketAddr,
 
        peer_addr: SocketAddr,
 
    ) -> Result<[PortId; 2], WrongStateError> {
 
        let Self { unphased: cu, phased } = self;
 
        match phased {
 
            ConnectorPhased::Communication(..) => Err(WrongStateError),
 
            ConnectorPhased::Setup(setup) => {
 
                let udp_index = setup.udp_endpoint_setups.len();
 
                let udp_cid = cu.inner.current_state.id_manager.new_component_id();
 
                let mut npid = || cu.inner.current_state.id_manager.new_port_id();
 
                let udp_cid = cu.current_state.id_manager.new_component_id();
 
                let mut npid = || cu.current_state.id_manager.new_port_id();
 
                let [nin, nout, uin, uout] = [npid(), npid(), npid(), npid()];
 

	
 
                cu.inner.current_state.port_info.insert(
 
                cu.current_state.port_info.insert(
 
                    nin,
 
                    PortInfo {
 
                        route: Route::LocalComponent,
 
                        polarity: Getter,
 
                        peer: Some(uout),
 
                        owner: cu.inner.native_component_id,
 
                        owner: cu.native_component_id,
 
                    },
 
                );
 
                cu.inner.current_state.port_info.insert(
 
                cu.current_state.port_info.insert(
 
                    nout,
 
                    PortInfo {
 
                        route: Route::LocalComponent,
 
                        polarity: Putter,
 
                        peer: Some(uin),
 
                        owner: cu.inner.native_component_id,
 
                        owner: cu.native_component_id,
 
                    },
 
                );
 
                cu.inner.current_state.port_info.insert(
 
                cu.current_state.port_info.insert(
 
                    uin,
 
                    PortInfo {
 
                        route: Route::UdpEndpoint { index: udp_index },
 
                        polarity: Getter,
 
                        peer: Some(uin),
 
                        owner: udp_cid,
 
                    },
 
                );
 
                cu.inner.current_state.port_info.insert(
 
                cu.current_state.port_info.insert(
 
                    uout,
 
                    PortInfo {
 
                        route: Route::UdpEndpoint { index: udp_index },
 
                        polarity: Putter,
 
                        peer: Some(uin),
 
                        owner: udp_cid,
 
                    },
 
                );
 
                setup.udp_endpoint_setups.push(UdpEndpointSetup {
 
                    local_addr,
 
                    peer_addr,
 
                    getter_for_incoming: nin,
 
                });
 
                Ok([nout, nin])
 
            }
 
        }
 
    }
 

	
 
    /// Adds a "dangling" port to the connector in the setup phase,
 
    /// to be formed into channel during the connect procedure with the given
 
    /// transport layer information.
 
    pub fn new_net_port(
 
        &mut self,
 
        polarity: Polarity,
 
        sock_addr: SocketAddr,
 
        endpoint_polarity: EndpointPolarity,
 
    ) -> Result<PortId, WrongStateError> {
 
        let Self { unphased: cu, phased } = self;
 
        match phased {
 
            ConnectorPhased::Communication(..) => Err(WrongStateError),
 
            ConnectorPhased::Setup(setup) => {
 
                let new_pid = cu.inner.current_state.id_manager.new_port_id();
 
                cu.inner.current_state.port_info.insert(
 
                let new_pid = cu.current_state.id_manager.new_port_id();
 
                cu.current_state.port_info.insert(
 
                    new_pid,
 
                    PortInfo {
 
                        route: Route::LocalComponent,
 
                        peer: None,
 
                        owner: cu.inner.native_component_id,
 
                        owner: cu.native_component_id,
 
                        polarity,
 
                    },
 
                );
 
                log!(
 
                    cu.inner.logger,
 
                    cu.logger,
 
                    "Added net port {:?} with polarity {:?} addr {:?} endpoint_polarity {:?}",
 
                    new_pid,
 
                    polarity,
 
                    &sock_addr,
 
                    endpoint_polarity
 
                );
 
                setup.net_endpoint_setups.push(NetEndpointSetup {
 
                    sock_addr,
 
                    endpoint_polarity,
 
                    getter_for_incoming: new_pid,
 
                });
 
                Ok(new_pid)
 
            }
 
        }
 
    }
 

	
 
    /// Finalizes the connector's setup procedure and forms a distributed system with
 
    /// all other connectors reachable through network channels. This procedure represents
 
    /// a synchronization barrier, and upon successful return, the connector can no longer add new network ports,
 
    /// but is ready to begin the first communication round.
 
    /// Initially, the connector has a singleton set of _batches_, the only element of which is empty.
 
    /// This single element starts off selected. The selected batch is modified with `put` and `get`,
 
    /// and new batches are added and selected with `next_batch`. See `sync` for an explanation of the
 
    /// purpose of these batches.
 
    pub fn connect(&mut self, timeout: Option<Duration>) -> Result<(), ConnectError> {
 
        use ConnectError as Ce;
 
        let Self { unphased: cu, phased } = self;
 
        match &phased {
 
            ConnectorPhased::Communication { .. } => {
 
                log!(cu.inner.logger, "Call to connecting in connected state");
 
                log!(cu.logger, "Call to connecting in connected state");
 
                Err(Ce::AlreadyConnected)
 
            }
 
            ConnectorPhased::Setup(setup) => {
 
                log!(cu.inner.logger, "~~~ CONNECT called timeout {:?}", timeout);
 
                log!(cu.logger, "~~~ CONNECT called timeout {:?}", timeout);
 
                let deadline = timeout.map(|to| Instant::now() + to);
 
                // connect all endpoints in parallel; send and receive peer ids through ports
 
                let mut endpoint_manager = new_endpoint_manager(
 
                    &mut *cu.inner.logger,
 
                    &mut *cu.logger,
 
                    &setup.net_endpoint_setups,
 
                    &setup.udp_endpoint_setups,
 
                    &mut cu.inner.current_state.port_info,
 
                    &mut cu.current_state.port_info,
 
                    &deadline,
 
                )?;
 
                log!(
 
                    cu.inner.logger,
 
                    cu.logger,
 
                    "Successfully connected {} endpoints. info now {:#?} {:#?}",
 
                    endpoint_manager.net_endpoint_store.endpoint_exts.len(),
 
                    &cu.inner.current_state.port_info,
 
                    &cu.current_state.port_info,
 
                    &endpoint_manager,
 
                );
 
                // leader election and tree construction
 
                let neighborhood = init_neighborhood(
 
                    cu.inner.current_state.id_manager.connector_id,
 
                    &mut *cu.inner.logger,
 
                    cu.current_state.id_manager.connector_id,
 
                    &mut *cu.logger,
 
                    &mut endpoint_manager,
 
                    &deadline,
 
                )?;
 
                log!(cu.inner.logger, "Successfully created neighborhood {:?}", &neighborhood);
 
                log!(cu.logger, "Successfully created neighborhood {:?}", &neighborhood);
 
                let mut comm = ConnectorCommunication {
 
                    round_index: 0,
 
                    endpoint_manager,
 
                    neighborhood,
 
                    native_batches: vec![Default::default()],
 
                    round_result: Ok(None),
 
                };
 
                if cfg!(feature = "session_optimization") {
 
                    session_optimize(cu, &mut comm, &deadline)?;
 
                }
 
                log!(cu.inner.logger, "connect() finished. setup phase complete");
 
                log!(cu.logger, "connect() finished. setup phase complete");
 
                *phased = ConnectorPhased::Communication(Box::new(comm));
 
                Ok(())
 
            }
 
        }
 
    }
 
}
 
fn new_endpoint_manager(
 
    logger: &mut dyn Logger,
 
    net_endpoint_setups: &[NetEndpointSetup],
 
    udp_endpoint_setups: &[UdpEndpointSetup],
 
    port_info: &mut HashMap<PortId, PortInfo>,
 
    deadline: &Option<Instant>,
 
) -> Result<EndpointManager, ConnectError> {
 
    ////////////////////////////////////////////
 
    use std::sync::atomic::{AtomicBool, Ordering::SeqCst};
 
    use ConnectError as Ce;
 
    const BOTH: Interest = Interest::READABLE.add(Interest::WRITABLE);
 
    const WAKER_PERIOD: Duration = Duration::from_millis(300);
 
    struct WakerState {
 
        continue_signal: AtomicBool,
 
        waker: mio::Waker,
 
    }
 
    impl WakerState {
 
        fn waker_loop(&self) {
 
            while self.continue_signal.load(SeqCst) {
 
                std::thread::sleep(WAKER_PERIOD);
 
                let _ = self.waker.wake();
 
            }
 
        }
 
        fn waker_stop(&self) {
 
            self.continue_signal.store(false, SeqCst);
 
            // TODO keep waker registered?
 
        }
 
    }
 
    struct Todo {
 
        // becomes completed once sent_local_port && recv_peer_port.is_some()
 
        // we send local port if we haven't already and we receive a writable event
 
        // we recv peer port if we haven't already and we receive a readbale event
 
        todo_endpoint: TodoEndpoint,
 
        endpoint_setup: NetEndpointSetup,
 
        sent_local_port: bool,          // true <-> I've sent my local port
 
        recv_peer_port: Option<PortId>, // Some(..) <-> I've received my peer's port
 
    }
 
    struct UdpTodo {
 
        // becomes completed once we receive our first writable event
 
        getter_for_incoming: PortId,
 
        sock: UdpSocket,
 
    }
 
    enum TodoEndpoint {
 
        Accepting(TcpListener),
 
        NetEndpoint(NetEndpoint),
 
    }
 
    ////////////////////////////////////////////
 

	
 
    // 1. Start to construct EndpointManager
 
    let mut waker_state: Option<Arc<WakerState>> = None;
 
    let mut poll = Poll::new().map_err(|_| Ce::PollInitFailed)?;
 
    let mut events =
 
        Events::with_capacity((net_endpoint_setups.len() + udp_endpoint_setups.len()) * 2 + 4);
 
    let [mut net_polled_undrained, udp_polled_undrained] = [VecSet::default(), VecSet::default()];
 
    let mut delayed_messages = vec![];
 

	
 
    // 2. Create net/udp TODOs, each already registered with poll
 
    let mut net_todos = net_endpoint_setups
 
        .iter()
 
        .enumerate()
 
        .map(|(index, endpoint_setup)| {
 
            let token = TokenTarget::NetEndpoint { index }.into();
 
            log!(logger, "Net endpoint {} beginning setup with {:?}", index, &endpoint_setup);
 
            let todo_endpoint = if let EndpointPolarity::Active = endpoint_setup.endpoint_polarity {
 
                let mut stream = TcpStream::connect(endpoint_setup.sock_addr)
 
                    .expect("mio::TcpStream connect should not fail!");
 
                poll.registry().register(&mut stream, token, BOTH).unwrap();
 
                TodoEndpoint::NetEndpoint(NetEndpoint { stream, inbox: vec![] })
 
            } else {
 
                let mut listener = TcpListener::bind(endpoint_setup.sock_addr)
 
                    .map_err(|_| Ce::BindFailed(endpoint_setup.sock_addr))?;
 
                poll.registry().register(&mut listener, token, BOTH).unwrap();
 
                TodoEndpoint::Accepting(listener)
 
            };
 
            Ok(Todo {
 
                todo_endpoint,
 
                sent_local_port: false,
 
                recv_peer_port: None,
 
                endpoint_setup: endpoint_setup.clone(),
 
            })
 
        })
 
        .collect::<Result<Vec<Todo>, ConnectError>>()?;
 
    let udp_todos = udp_endpoint_setups
 
        .iter()
 
        .enumerate()
 
        .map(|(index, endpoint_setup)| {
 
            let mut sock = UdpSocket::bind(endpoint_setup.local_addr)
 
                .map_err(|_| Ce::BindFailed(endpoint_setup.local_addr))?;
 
            sock.connect(endpoint_setup.peer_addr)
 
                .map_err(|_| Ce::UdpConnectFailed(endpoint_setup.peer_addr))?;
 
            poll.registry()
 
                .register(&mut sock, TokenTarget::UdpEndpoint { index }.into(), Interest::WRITABLE)
 
                .unwrap();
 
            Ok(UdpTodo { sock, getter_for_incoming: endpoint_setup.getter_for_incoming })
 
        })
 
        .collect::<Result<Vec<UdpTodo>, ConnectError>>()?;
 

	
 
    // Initially, (1) no net connections have failed, and (2) all udp and net endpoint setups are incomplete
 
    let mut net_connect_retry_later: HashSet<usize> = Default::default();
 
    let mut setup_incomplete: HashSet<TokenTarget> = {
 
        let net_todo_targets_iter =
 
            (0..net_todos.len()).map(|index| TokenTarget::NetEndpoint { index });
 
        let udp_todo_targets_iter =
 
            (0..udp_todos.len()).map(|index| TokenTarget::UdpEndpoint { index });
 
        net_todo_targets_iter.chain(udp_todo_targets_iter).collect()
 
    };
 
    // progress by reacting to poll events. continue until every endpoint is set up
 
    while !setup_incomplete.is_empty() {
 
        let remaining = if let Some(deadline) = deadline {
 
            Some(deadline.checked_duration_since(Instant::now()).ok_or(Ce::Timeout)?)
 
        } else {
 
            None
 
        };
 
        poll.poll(&mut events, remaining).map_err(|_| Ce::PollFailed)?;
 
        for event in events.iter() {
 
            let token = event.token();
 
            let token_target = TokenTarget::from(token);
 
            match token_target {
 
                TokenTarget::Waker => {
 
                    log!(
 
                        logger,
 
                        "Notification from waker. connect_failed is {:?}",
 
                        net_connect_retry_later.iter()
 
                    );
 
                    assert!(waker_state.is_some());
 
                    for net_index in net_connect_retry_later.drain() {
 
                        let net_todo = &mut net_todos[net_index];
 
                        log!(
 
                            logger,
 
                            "Restarting connection with endpoint {:?} {:?}",
 
                            net_index,
 
                            net_todo.endpoint_setup.sock_addr
 
                        );
 
                        match &mut net_todo.todo_endpoint {
 
                            TodoEndpoint::NetEndpoint(endpoint) => {
 
                                let mut new_stream =
 
                                    TcpStream::connect(net_todo.endpoint_setup.sock_addr)
 
                                        .expect("mio::TcpStream connect should not fail!");
 
                                std::mem::swap(&mut endpoint.stream, &mut new_stream);
 
                                let token = TokenTarget::NetEndpoint { index: net_index }.into();
 
                                poll.registry()
 
                                    .register(&mut endpoint.stream, token, BOTH)
 
                                    .unwrap();
 
                            }
 
                            _ => unreachable!(),
 
                        }
 
                    }
 
                }
 
                TokenTarget::UdpEndpoint { index } => {
 
                    if !setup_incomplete.contains(&token_target) {
 
                        // spurious wakeup. this endpoint has already been set up!
 
                        continue;
 
                    }
 
                    let udp_todo: &UdpTodo = &udp_todos[index];
 
                    if event.is_error() {
 
                        return Err(Ce::BindFailed(udp_todo.sock.local_addr().unwrap()));
 
                    }
 
                    setup_incomplete.remove(&token_target);
 
                }
 
                TokenTarget::NetEndpoint { index } => {
 
                    let net_todo = &mut net_todos[index];
 
                    if let TodoEndpoint::Accepting(listener) = &mut net_todo.todo_endpoint {
 
                        // FIRST try complete this connection
 
                        match listener.accept() {
 
                            Err(e) if would_block(&e) => continue, // spurious wakeup
 
                            Err(e) if err_would_block(&e) => continue, // spurious wakeup
 
                            Err(_) => {
 
                                log!(logger, "accept() failure on index {}", index);
 
                                return Err(Ce::AcceptFailed(listener.local_addr().unwrap()));
 
                            }
 
                            Ok((mut stream, peer_addr)) => {
 
                                // successfully accepted the active peer
 
                                // reusing the token, but now for the stream and not the listener
 
                                poll.registry().deregister(listener).unwrap();
 
                                poll.registry().register(&mut stream, token, BOTH).unwrap();
 
                                log!(
 
                                    logger,
 
                                    "Endpoint[{}] accepted a connection from {:?}",
 
                                    index,
 
                                    peer_addr
 
                                );
 
                                let net_endpoint = NetEndpoint { stream, inbox: vec![] };
 
                                net_todo.todo_endpoint = TodoEndpoint::NetEndpoint(net_endpoint);
 
                            }
 
                        }
 
                    }
 
                    if let TodoEndpoint::NetEndpoint(net_endpoint) = &mut net_todo.todo_endpoint {
 
                        if event.is_error() {
 
                            if net_todo.endpoint_setup.endpoint_polarity
 
                                == EndpointPolarity::Passive
 
                            {
 
                                // right now you cannot retry an acceptor. return failure
 
                                return Err(Ce::AcceptFailed(
 
                                    net_endpoint.stream.local_addr().unwrap(),
 
                                ));
 
                            }
 
                            // this actively-connecting endpoint failed to connect!
 
                            if net_connect_retry_later.insert(index) {
 
                                log!(
 
                                    logger,
 
                                    "Connection failed for {:?}. List is {:?}",
 
                                    index,
 
                                    net_connect_retry_later.iter()
 
                                );
 
                                poll.registry().deregister(&mut net_endpoint.stream).unwrap();
 
                            } else {
 
                                // spurious wakeup. already scheduled to retry connect later
 
                                continue;
 
                            }
 
                            if waker_state.is_none() {
 
                                log!(logger, "First connect failure. Starting waker thread");
 
                                let arc = Arc::new(WakerState {
 
                                    waker: mio::Waker::new(
 
                                        poll.registry(),
 
                                        TokenTarget::Waker.into(),
 
                                    )
 
                                    .unwrap(),
 
                                    continue_signal: true.into(),
 
                                });
 
                                let moved_arc = arc.clone();
 
                                waker_state = Some(arc);
 
                                std::thread::spawn(move || moved_arc.waker_loop());
 
                            }
 
                            continue;
 
                        }
 
                        // event wasn't ERROR
 
                        if net_connect_retry_later.contains(&index) {
 
                            // spurious wakeup. already scheduled to retry connect later
 
                            continue;
 
                        }
 
                        if !setup_incomplete.contains(&token_target) {
 
                            // spurious wakeup. this endpoint has already been completed!
 
                            if event.is_readable() {
 
                                net_polled_undrained.insert(index);
 
                            }
 
                            continue;
 
                        }
 
                        let local_info = port_info
 
                            .get_mut(&net_todo.endpoint_setup.getter_for_incoming)
 
                            .unwrap();
 
                        if event.is_writable() && !net_todo.sent_local_port {
 
                            // can write and didn't send setup msg yet? Do so!
 
                            let msg = Msg::SetupMsg(SetupMsg::MyPortInfo(MyPortInfo {
 
                                owner: local_info.owner,
 
                                polarity: local_info.polarity,
 
                                port: net_todo.endpoint_setup.getter_for_incoming,
 
                            }));
 
                            net_endpoint
 
                                .send(&msg)
 
                                .map_err(|e| {
 
                                    Ce::NetEndpointSetupError(
 
                                        net_endpoint.stream.local_addr().unwrap(),
 
                                        e,
 
                                    )
 
                                })
 
                                .unwrap();
 
                            log!(logger, "endpoint[{}] sent msg {:?}", index, &msg);
 
                            net_todo.sent_local_port = true;
 
                        }
 
                        if event.is_readable() && net_todo.recv_peer_port.is_none() {
 
                            // can read and didn't recv setup msg yet? Do so!
 
                            let maybe_msg = net_endpoint.try_recv(logger).map_err(|e| {
 
                                Ce::NetEndpointSetupError(
 
                                    net_endpoint.stream.local_addr().unwrap(),
 
                                    e,
 
                                )
 
                            })?;
 
                            if maybe_msg.is_some() && !net_endpoint.inbox.is_empty() {
 
                                net_polled_undrained.insert(index);
 
                            }
 
                            match maybe_msg {
 
                                None => {} // msg deserialization incomplete
 
                                Some(Msg::SetupMsg(SetupMsg::MyPortInfo(peer_info))) => {
 
                                    log!(
 
                                        logger,
 
                                        "endpoint[{}] got peer info {:?}",
 
                                        index,
 
                                        peer_info
 
                                    );
 
                                    if peer_info.polarity == local_info.polarity {
 
                                        return Err(ConnectError::PortPeerPolarityMismatch(
 
                                            net_todo.endpoint_setup.getter_for_incoming,
 
                                        ));
 
                                    }
 
                                    net_todo.recv_peer_port = Some(peer_info.port);
 
                                    // 1. finally learned the peer of this port!
 
                                    local_info.peer = Some(peer_info.port);
 
                                    // 2. learned the info of this peer port
 
                                    port_info.entry(peer_info.port).or_insert(PortInfo {
 
                                        peer: Some(net_todo.endpoint_setup.getter_for_incoming),
 
                                        polarity: peer_info.polarity,
 
                                        owner: peer_info.owner,
 
                                        route: Route::NetEndpoint { index },
 
                                    });
 
                                }
 
                                Some(inappropriate_msg) => {
 
                                    log!(
 
                                        logger,
 
                                        "delaying msg {:?} during channel setup phase",
 
                                        inappropriate_msg
 
                                    );
 
                                    delayed_messages.push((index, inappropriate_msg));
 
                                }
 
                            }
 
                        }
 
                        // is the setup for this net_endpoint now complete?
 
                        if net_todo.sent_local_port && net_todo.recv_peer_port.is_some() {
 
                            // yes! connected, sent my info and received peer's info
 
                            setup_incomplete.remove(&token_target);
 
                            log!(logger, "endpoint[{}] is finished!", index);
 
                        }
 
                    }
 
                }
 
            }
 
        }
 
        events.clear();
 
    }
 
    log!(logger, "Endpoint setup complete! Cleaning up and building structures");
 
    if let Some(ws) = waker_state.take() {
 
        ws.waker_stop();
 
    }
 
    let net_endpoint_exts = net_todos
 
        .into_iter()
 
        .enumerate()
 
        .map(|(index, Todo { todo_endpoint, endpoint_setup, .. })| NetEndpointExt {
 
            net_endpoint: match todo_endpoint {
 
                TodoEndpoint::NetEndpoint(mut net_endpoint) => {
 
                    let token = TokenTarget::NetEndpoint { index }.into();
 
                    poll.registry()
 
                        .reregister(&mut net_endpoint.stream, token, Interest::READABLE)
 
                        .unwrap();
 
                    net_endpoint
 
                }
 
                _ => unreachable!(),
 
            },
 
            getter_for_incoming: endpoint_setup.getter_for_incoming,
 
        })
 
        .collect();
 
    let udp_endpoint_exts = udp_todos
 
        .into_iter()
 
        .enumerate()
 
        .map(|(index, udp_todo)| {
 
            let UdpTodo { mut sock, getter_for_incoming } = udp_todo;
 
            let token = TokenTarget::UdpEndpoint { index }.into();
 
            poll.registry().reregister(&mut sock, token, Interest::READABLE).unwrap();
 
            UdpEndpointExt {
 
                sock,
 
                outgoing_payloads: Default::default(),
 
                received_this_round: false,
 
                getter_for_incoming,
 
            }
 
        })
 
        .collect();
 
    Ok(EndpointManager {
 
        poll,
 
        events,
 
        undelayed_messages: delayed_messages, // no longer delayed
 
        delayed_messages: Default::default(),
 
@@ -592,358 +615,354 @@ fn init_neighborhood(
 
        awaiting.clear();
 
        let msg = S(Sm::LeaderWave { wave_leader: ws.leader });
 
        for index in em.index_iter() {
 
            if Some(index) != ws.parent {
 
                em.send_to_setup(index, &msg)?;
 
                awaiting.insert(index);
 
            }
 
        }
 
        Ok(())
 
    }
 
    ///////////////////////
 
    /*
 
    Conceptually, we have two distinct disstributed algorithms back-to-back
 
    1. Leader election using echo algorithm with extinction.
 
        - Each connector initiates a wave tagged with their ID
 
        - Connectors participate in waves of GREATER ID, abandoning previous waves
 
        - Only the wave of the connector with GREATEST ID completes, whereupon they are the leader
 
    2. Tree construction
 
        - The leader broadcasts their leadership with msg A
 
        - Upon receiving their first announcement, connectors reply B, and send A to all peers
 
        - A controller exits once they have received A or B from each neighbor
 

	
 
    The actual implementation is muddier, because non-leaders aren't aware of termiantion of algorithm 1,
 
    so they rely on receipt of the leader's announcement to realize that algorithm 2 has begun.
 

	
 
    NOTE the distinction between PARENT and LEADER
 
    */
 
    log!(logger, "beginning neighborhood construction");
 
    if em.num_net_endpoints() == 0 {
 
        log!(logger, "Edge case of no neighbors! No parent an no children!");
 
        return Ok(Neighborhood { parent: None, children: VecSet::new(vec![]) });
 
    }
 
    log!(logger, "Have {} endpoints. Must participate in distributed alg.", em.num_net_endpoints());
 
    let mut awaiting = HashSet::with_capacity(em.num_net_endpoints());
 
    // 1+ neighbors. Leader can only be learned by receiving messages
 
    // loop ends when I know my sink tree parent (implies leader was elected)
 
    let election_result: WaveState = {
 
        // initially: No parent, I'm the best leader.
 
        let mut best_wave = WaveState { parent: None, leader: connector_id };
 
        // start a wave for this initial state
 
        do_wave(em, &mut awaiting, &best_wave)?;
 
        // with 1+ neighbors, progress is only made in response to incoming messages
 
        em.undelay_all();
 
        'election: loop {
 
            log!(logger, "Election loop. awaiting {:?}...", awaiting.iter());
 
            let (recv_index, msg) = em.try_recv_any_setup(logger, deadline)?;
 
            log!(logger, "Received from index {:?} msg {:?}", &recv_index, &msg);
 
            match msg {
 
                S(Sm::LeaderAnnounce { tree_leader }) => {
 
                    let election_result =
 
                        WaveState { leader: tree_leader, parent: Some(recv_index) };
 
                    log!(logger, "Election lost! Result {:?}", &election_result);
 
                    assert!(election_result.leader >= best_wave.leader);
 
                    assert_ne!(election_result.leader, connector_id);
 
                    break 'election election_result;
 
                }
 
                S(Sm::LeaderWave { wave_leader }) => {
 
                    use Ordering as O;
 
                    match wave_leader.cmp(&best_wave.leader) {
 
                        O::Less => log!(
 
                            logger,
 
                            "Ignoring wave with Id {:?}<{:?}",
 
                            wave_leader,
 
                            best_wave.leader
 
                        ),
 
                        O::Greater => {
 
                            log!(
 
                                logger,
 
                                "Joining wave with Id {:?}>{:?}",
 
                                wave_leader,
 
                                best_wave.leader
 
                            );
 
                            best_wave = WaveState { leader: wave_leader, parent: Some(recv_index) };
 
                            log!(logger, "New wave state {:?}", &best_wave);
 
                            do_wave(em, &mut awaiting, &best_wave)?;
 
                            if awaiting.is_empty() {
 
                                log!(logger, "Special case! Only neighbor is parent. Replying to {:?} msg {:?}", recv_index, &msg);
 
                                em.send_to_setup(recv_index, &msg)?;
 
                            }
 
                        }
 
                        O::Equal => {
 
                            assert!(awaiting.remove(&recv_index));
 
                            log!(
 
                                logger,
 
                                "Wave reply from index {:?} for leader {:?}. Now awaiting {} replies",
 
                                recv_index,
 
                                best_wave.leader,
 
                                awaiting.len()
 
                            );
 
                            if awaiting.is_empty() {
 
                                if let Some(parent) = best_wave.parent {
 
                                    log!(
 
                                        logger,
 
                                        "Sub-wave done! replying to parent {:?} msg {:?}",
 
                                        parent,
 
                                        &msg
 
                                    );
 
                                    em.send_to_setup(parent, &msg)?;
 
                                } else {
 
                                    let election_result: WaveState = best_wave;
 
                                    log!(logger, "Election won! Result {:?}", &election_result);
 
                                    break 'election election_result;
 
                                }
 
                            }
 
                        }
 
                    }
 
                }
 
                msg @ S(Sm::YouAreMyParent) | msg @ S(Sm::MyPortInfo(_)) => {
 
                    log!(logger, "Endpont {:?} sent unexpected msg! {:?}", recv_index, &msg);
 
                    return Err(Ce::SetupAlgMisbehavior);
 
                }
 
                msg @ S(Sm::SessionScatter { .. })
 
                | msg @ S(Sm::SessionGather { .. })
 
                | msg @ Msg::CommMsg { .. } => {
 
                    log!(logger, "delaying msg {:?} during election algorithm", msg);
 
                    em.delayed_messages.push((recv_index, msg));
 
                }
 
            }
 
        }
 
    };
 

	
 
    // starting algorithm 2. Send a message to every neighbor
 
    log!(logger, "Starting tree construction. Step 1: send one msg per neighbor");
 
    awaiting.clear();
 
    for index in em.index_iter() {
 
        if Some(index) == election_result.parent {
 
            em.send_to_setup(index, &S(Sm::YouAreMyParent))?;
 
        } else {
 
            awaiting.insert(index);
 
            em.send_to_setup(
 
                index,
 
                &S(Sm::LeaderAnnounce { tree_leader: election_result.leader }),
 
            )?;
 
        }
 
    }
 
    let mut children = vec![];
 
    em.undelay_all();
 
    while !awaiting.is_empty() {
 
        log!(logger, "Tree construction_loop loop. awaiting {:?}...", awaiting.iter());
 
        let (recv_index, msg) = em.try_recv_any_setup(logger, deadline)?;
 
        log!(logger, "Received from index {:?} msg {:?}", &recv_index, &msg);
 
        match msg {
 
            S(Sm::LeaderAnnounce { .. }) => {
 
                // not a child
 
                log!(
 
                    logger,
 
                    "Got reply from non-child index {:?}. Children: {:?}",
 
                    recv_index,
 
                    children.iter()
 
                );
 
                if !awaiting.remove(&recv_index) {
 
                    return Err(Ce::SetupAlgMisbehavior);
 
                }
 
            }
 
            S(Sm::YouAreMyParent) => {
 
                if !awaiting.remove(&recv_index) {
 
                    log!(
 
                        logger,
 
                        "Got reply from child index {:?}. Children before... {:?}",
 
                        recv_index,
 
                        children.iter()
 
                    );
 
                    return Err(Ce::SetupAlgMisbehavior);
 
                }
 
                children.push(recv_index);
 
            }
 
            msg @ S(Sm::MyPortInfo(_)) | msg @ S(Sm::LeaderWave { .. }) => {
 
                log!(logger, "discarding old message {:?} during election", msg);
 
            }
 
            msg @ S(Sm::SessionScatter { .. })
 
            | msg @ S(Sm::SessionGather { .. })
 
            | msg @ Msg::CommMsg { .. } => {
 
                log!(logger, "delaying msg {:?} during election", msg);
 
                em.delayed_messages.push((recv_index, msg));
 
            }
 
        }
 
    }
 
    children.shrink_to_fit();
 
    let neighborhood =
 
        Neighborhood { parent: election_result.parent, children: VecSet::new(children) };
 
    log!(logger, "Neighborhood constructed {:?}", &neighborhood);
 
    Ok(neighborhood)
 
}
 

	
 
fn session_optimize(
 
    cu: &mut ConnectorUnphased,
 
    comm: &mut ConnectorCommunication,
 
    deadline: &Option<Instant>,
 
) -> Result<(), ConnectError> {
 
    ////////////////////////////////////////
 
    use {ConnectError as Ce, Msg::SetupMsg as S, SetupMsg as Sm};
 
    ////////////////////////////////////////
 
    log!(cu.inner.logger, "Beginning session optimization");
 
    log!(cu.logger, "Beginning session optimization");
 
    // populate session_info_map from a message per child
 
    let mut unoptimized_map: HashMap<ConnectorId, SessionInfo> = Default::default();
 
    let mut awaiting: HashSet<usize> = comm.neighborhood.children.iter().copied().collect();
 
    comm.endpoint_manager.undelay_all();
 
    while !awaiting.is_empty() {
 
        log!(
 
            cu.inner.logger,
 
            cu.logger,
 
            "Session gather loop. awaiting info from children {:?}...",
 
            awaiting.iter()
 
        );
 
        let (recv_index, msg) =
 
            comm.endpoint_manager.try_recv_any_setup(&mut *cu.inner.logger, deadline)?;
 
        log!(cu.inner.logger, "Received from index {:?} msg {:?}", &recv_index, &msg);
 
            comm.endpoint_manager.try_recv_any_setup(&mut *cu.logger, deadline)?;
 
        log!(cu.logger, "Received from index {:?} msg {:?}", &recv_index, &msg);
 
        match msg {
 
            S(Sm::SessionGather { unoptimized_map: child_unoptimized_map }) => {
 
                if !awaiting.remove(&recv_index) {
 
                    log!(
 
                        cu.inner.logger,
 
                        cu.logger,
 
                        "Wasn't expecting session info from {:?}. Got {:?}",
 
                        recv_index,
 
                        &child_unoptimized_map
 
                    );
 
                    return Err(Ce::SetupAlgMisbehavior);
 
                }
 
                unoptimized_map.extend(child_unoptimized_map.into_iter());
 
            }
 
            msg @ S(Sm::YouAreMyParent)
 
            | msg @ S(Sm::MyPortInfo(..))
 
            | msg @ S(Sm::LeaderAnnounce { .. })
 
            | msg @ S(Sm::LeaderWave { .. }) => {
 
                log!(cu.inner.logger, "discarding old message {:?} during election", msg);
 
                log!(cu.logger, "discarding old message {:?} during election", msg);
 
            }
 
            msg @ S(Sm::SessionScatter { .. }) => {
 
                log!(
 
                    cu.inner.logger,
 
                    cu.logger,
 
                    "Endpoint {:?} sent unexpected scatter! {:?} I've not contributed yet!",
 
                    recv_index,
 
                    &msg
 
                );
 
                return Err(Ce::SetupAlgMisbehavior);
 
            }
 
            msg @ Msg::CommMsg(..) => {
 
                log!(cu.inner.logger, "delaying msg {:?} during session optimization", msg);
 
                log!(cu.logger, "delaying msg {:?} during session optimization", msg);
 
                comm.endpoint_manager.delayed_messages.push((recv_index, msg));
 
            }
 
        }
 
    }
 
    log!(
 
        cu.inner.logger,
 
        cu.logger,
 
        "Gathered all children's maps. ConnectorId set is... {:?}",
 
        unoptimized_map.keys()
 
    );
 
    let my_session_info = SessionInfo {
 
        port_info: cu.inner.current_state.port_info.clone(),
 
        port_info: cu.current_state.port_info.clone(),
 
        proto_components: cu.proto_components.clone(),
 
        serde_proto_description: SerdeProtocolDescription(cu.proto_description.clone()),
 
        endpoint_incoming_to_getter: comm
 
            .endpoint_manager
 
            .net_endpoint_store
 
            .endpoint_exts
 
            .iter()
 
            .map(|ee| ee.getter_for_incoming)
 
            .collect(),
 
    };
 
    unoptimized_map.insert(cu.inner.current_state.id_manager.connector_id, my_session_info);
 
    log!(
 
        cu.inner.logger,
 
        "Inserting my own info. Unoptimized subtree map is {:?}",
 
        &unoptimized_map
 
    );
 
    unoptimized_map.insert(cu.current_state.id_manager.connector_id, my_session_info);
 
    log!(cu.logger, "Inserting my own info. Unoptimized subtree map is {:?}", &unoptimized_map);
 

	
 
    // acquire the optimized info...
 
    let optimized_map = if let Some(parent) = comm.neighborhood.parent {
 
        // ... as a message from my parent
 
        log!(cu.inner.logger, "Forwarding gathered info to parent {:?}", parent);
 
        log!(cu.logger, "Forwarding gathered info to parent {:?}", parent);
 
        let msg = S(Sm::SessionGather { unoptimized_map });
 
        comm.endpoint_manager.send_to_setup(parent, &msg)?;
 
        'scatter_loop: loop {
 
            log!(
 
                cu.inner.logger,
 
                cu.logger,
 
                "Session scatter recv loop. awaiting info from children {:?}...",
 
                awaiting.iter()
 
            );
 
            let (recv_index, msg) =
 
                comm.endpoint_manager.try_recv_any_setup(&mut *cu.inner.logger, deadline)?;
 
            log!(cu.inner.logger, "Received from index {:?} msg {:?}", &recv_index, &msg);
 
                comm.endpoint_manager.try_recv_any_setup(&mut *cu.logger, deadline)?;
 
            log!(cu.logger, "Received from index {:?} msg {:?}", &recv_index, &msg);
 
            match msg {
 
                S(Sm::SessionScatter { optimized_map }) => {
 
                    if recv_index != parent {
 
                        log!(cu.inner.logger, "I expected the scatter from my parent only!");
 
                        log!(cu.logger, "I expected the scatter from my parent only!");
 
                        return Err(Ce::SetupAlgMisbehavior);
 
                    }
 
                    break 'scatter_loop optimized_map;
 
                }
 
                msg @ Msg::CommMsg { .. } => {
 
                    log!(cu.inner.logger, "delaying msg {:?} during scatter recv", msg);
 
                    log!(cu.logger, "delaying msg {:?} during scatter recv", msg);
 
                    comm.endpoint_manager.delayed_messages.push((recv_index, msg));
 
                }
 
                msg @ S(Sm::SessionGather { .. })
 
                | msg @ S(Sm::YouAreMyParent)
 
                | msg @ S(Sm::MyPortInfo(..))
 
                | msg @ S(Sm::LeaderAnnounce { .. })
 
                | msg @ S(Sm::LeaderWave { .. }) => {
 
                    log!(cu.inner.logger, "discarding old message {:?} during election", msg);
 
                    log!(cu.logger, "discarding old message {:?} during election", msg);
 
                }
 
            }
 
        }
 
    } else {
 
        // by computing it myself
 
        log!(cu.inner.logger, "I am the leader! I will optimize this session");
 
        leader_session_map_optimize(&mut *cu.inner.logger, unoptimized_map)?
 
        log!(cu.logger, "I am the leader! I will optimize this session");
 
        leader_session_map_optimize(&mut *cu.logger, unoptimized_map)?
 
    };
 
    log!(
 
        cu.inner.logger,
 
        cu.logger,
 
        "Optimized info map is {:?}. Sending to children {:?}",
 
        &optimized_map,
 
        comm.neighborhood.children.iter()
 
    );
 
    log!(cu.inner.logger, "All session info dumped!: {:#?}", &optimized_map);
 
    log!(cu.logger, "All session info dumped!: {:#?}", &optimized_map);
 
    let optimized_info = optimized_map
 
        .get(&cu.inner.current_state.id_manager.connector_id)
 
        .get(&cu.current_state.id_manager.connector_id)
 
        .expect("HEY NO INFO FOR ME?")
 
        .clone();
 
    let msg = S(Sm::SessionScatter { optimized_map });
 
    for &child in comm.neighborhood.children.iter() {
 
        comm.endpoint_manager.send_to_setup(child, &msg)?;
 
    }
 
    apply_optimizations(cu, comm, optimized_info)?;
 
    log!(cu.inner.logger, "Session optimizations applied");
 
    log!(cu.logger, "Session optimizations applied");
 
    Ok(())
 
}
 
fn leader_session_map_optimize(
 
    logger: &mut dyn Logger,
 
    unoptimized_map: HashMap<ConnectorId, SessionInfo>,
 
) -> Result<HashMap<ConnectorId, SessionInfo>, ConnectError> {
 
    log!(logger, "Session map optimize START");
 
    log!(logger, "Session map optimize END");
 
    Ok(unoptimized_map)
 
}
 
fn apply_optimizations(
 
    cu: &mut ConnectorUnphased,
 
    comm: &mut ConnectorCommunication,
 
    session_info: SessionInfo,
 
) -> Result<(), ConnectError> {
 
    let SessionInfo {
 
        proto_components,
 
        port_info,
 
        serde_proto_description,
 
        endpoint_incoming_to_getter,
 
    } = session_info;
 
    // TODO some info which should be read-only can be mutated with the current scheme
 
    cu.inner.current_state.port_info = port_info;
 
    cu.current_state.port_info = port_info;
 
    cu.proto_components = proto_components;
 
    cu.proto_description = serde_proto_description.0;
 
    for (ee, getter) in comm
 
        .endpoint_manager
 
        .net_endpoint_store
 
        .endpoint_exts
 
        .iter_mut()
 
        .zip(endpoint_incoming_to_getter)
 
    {
 
        ee.getter_for_incoming = getter;
 
    }
 
    Ok(())
 
}
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