Module ipc 

IPC Protocol with Multiplexing and Streaming

From mm.md Task 7.1: Pipelined IPC Protocol

Problem

Current IPC is request-response, blocking client during server work:

Client: Send Request -> Wait -> Receive Response -> Send Next Request
Latency: sum of all request latencies

Solution

Pipelining with request IDs and async responses:

+------------+     +------------+
|   Client   |     |   Server   |
+------------+     +------------+
      |                   |
      |--- Req(id=1) ---->|
      |--- Req(id=2) ---->|
      |--- Req(id=3) ---->|  (no wait)
      |                   |
      |<-- Resp(id=2) ----|  (out-of-order OK)
      |<-- Resp(id=1) ----|
      |<-- Resp(id=3) ----|
      |                   |

Protocol: Unix domain socket with length-prefixed messages
Frame: [4-byte length][request_id: u64][msg_type: u8][payload...]

Benefits

• No head-of-line blocking
• Batched network I/O
• Supports streaming responses for large result sets
• Backpressure through flow control

Structs

BatchRequest

Batch request builder for efficient pipelining

FlowControl

Flow control state

Frame

Complete IPC frame

FrameHeader

IPC frame header

FrameReader

Frame reader for parsing incoming frames

FrameWriter

Frame writer for serializing outgoing frames

IpcServer

IPC server for handling incoming connections

RequestMultiplexer

Request multiplexer for pipelining

StreamWriter

Stream response writer for sending chunked results

Enums

IpcError

IPC error types

MessageType

Message types in the IPC protocol

Traits

RequestHandler

Request handler trait for server-side processing

Type Aliases

RequestId

Request ID for tracking pipelined requests

StreamId

Stream ID for multiplexed streams