Crate fracpack 

Rust support for the fracpack format.

Psibase uses a new binary format, fracpack, which has the following goals:

• Quickly pack and unpack data, making it suitable for service-to-service communication, node-to-node communication, blockchain-to-outside communication, and database storage.
• Forwards and backwards compatibility; it supports adding new optional fields to the end of structs and tuples, even when they are embedded in variable-length vectors, fixed-length arrays, optional, and other structs and tuples.
• Option to read without unpacking (almost zero-copy); helps to efficiently handle large data. TODO: this library doesn’t implement this feature yet.
• Doesn’t require a code generator to support either C++ or Rust; macros and metaprogramming handle it.
• Efficient compression when combined with the compression algorithm from Cap ‘n’ Proto.

Example use

use fracpack::{Pack, Unpack, Result};

#[derive(Pack, Unpack, PartialEq, Debug)]
#[fracpack(fracpack_mod = "fracpack")]
struct Example {
    a_string: String,
    a_tuple: (u32, String),
}

let orig = Example {
    a_string: "content".into(),
    a_tuple: (1234, "5678".into()),
};

// Convert to fracpack format
let packed: Vec<u8> = orig.packed();

// Convert from fracpack format
let unpacked = Example::unpacked(&packed)?;

assert_eq!(orig, unpacked);

Note: #[fracpack(fracpack_mod = "fracpack")] is only needed when using the fracpack library directly instead of through the psibase crate.

Caution

It’s easy to accidentally convert from a fixed-size array reference (&[T;7]) to a slice (&[T]). This matters to fracpack, which has different, and incompatible, encodings for the two types.

Re-exports

pub use indexmap;

Structs

CompiledSchema

CustomTypes

FracInputStream

FunctionType

Nested

Schema

SchemaBuilder

SchemaDifference

SchemaMatcher

Enums

AnyType

CompiledType

Error

Traits

CustomHandler

Pack

Convert to fracpack format

ToSchema

Unpack

Unpack fracpack data

UnpackOwned

Use this trait on generic functions instead of Unpack when the deserialized data may only be owned instead of borrowed from the source.

VisitTypes

Functions

standard_types

Type Aliases

Result

Derive Macros

Pack

ToSchema

Unpack