Crate capnp

Cap’n Proto Runtime Library

This crate contains basic facilities for reading and writing Cap’n Proto messages in Rust. It is intended to be used in conjunction with code generated by the capnpc-rust crate.

Modules

• any_pointer
  Untyped pointer that can be cast to any struct, list, or capability type.
• any_pointer_list
  List of AnyPointers.
• capability
  Hooks for for the RPC system.
• capability_list
  List of capabilities.
• constant
  Helper type for generated Struct and List constants.
• data
  Sequence of bytes.
• data_list
  List of sequences of bytes.
• dynamic_list
  Dynamically-typed lists.
• dynamic_struct
  Dynamically-typed structs.
• dynamic_value
  Dynamically typed values.
• enum_list
  List of enums.
• introspect
  Traits and types to support run-time type introspection, i.e. reflection.
• io
  Custom I/O traits that roughly mirror std::io::{Read, BufRead, Write}. This extra layer of indirection enables support of no-std environments.
• list_list
  List of lists.
• message
  Untyped root container for a Cap’n Proto value.
• primitive_list
  List of primitives.
• private
  Implementation details that should never be directly used by clients.
• raw
  Functions providing low level access to encoded data.
• schema
  Convenience wrappers of the datatypes defined in schema.capnp.
• schema_capnp
  Code generated from schema.capnp.
• serialize
  Reading and writing of messages using the standard stream framing, where each message is preceded by a segment table indicating the size of its segments.
• serialize_packed
  Reading and writing of messages using the packed stream encoding.
• struct_list
  List of structs.
• text
  UTF-8 encoded text.
• text_list
  List of strings containing UTF-8 encoded text.
• traits

Structs

• Error
  Describes an arbitrary error that prevented an operation from completing.
• MessageSize
  Size of a message. Every generated struct has a method .total_size() that returns this.
• NotInSchema
  An enum value or union discriminant that was not found among those defined in a schema.
• Word
  8 bytes, aligned to an 8-byte boundary.

Enums

• ErrorKind
  The general nature of an error. The purpose of this enum is not to describe the error itself, but rather to describe how the client might want to respond to the error.
• OutputSegments
  Helper struct that allows MessageBuilder::get_segments_for_output() to avoid heap allocations in the single-segment case.

Functions

• word
  Constructs a word with the given bytes.

Type Aliases

• Result
  Because messages are lazily validated, the return type of any method that reads a pointer field must be wrapped in a Result.