Crate sval_protobuf

protobuf support for sval.

This library implements a binary encoding for sval::Values that’s compatible with the protobuf wire format.

This library doesn’t depend on protoc or any code generation tools; any implementation of sval::Value can be encoded. You can use it in cases where standard code generation is either impractical or produces undesirable results. It supports some more niche use-cases like embedding already encoded messages into others without needing to parse them first.

This library only supports encoding.

Specifics

This section uses protoscope syntax for encoded messages.

Messages

If you #[derive(Value)], your structs are encoded as messages:

#[derive(Value)]
pub struct Record<'a> {
    id: i32,
    title: &'a str,
    data: &'a str,
}

Record {
    id: 42,
    title: "My Message",
    data: "Some amazing content",
}

1: 42
2: {"My Message"}
3: {"Some amazing content"}

Specify an #[sval(index)] on fields to set the field number explicitly:

#[derive(Value)]
pub struct ManuallyIndexed<'a> {
    #[sval(index = 3)]
    id: i32,
    #[sval(index = 7)]
    title: &'a str,
}

ManuallyIndexed {
    id: 42,
    title: "My Message",
}

3: 42
7: {"My Message"}

Anonymous tuples are also messages:

(
    42,
    "My Message",
    "Some amazing content",
)

1: 42
2: {"My Message"}
3: {"Some amazing content"}

128bit numbers are always encoded as a 16 byte buffer with the little-endian bytes of the value.

Re-exports

pub use crate::buf::Capacity;

Modules

buf

Buffering writer for protobuf.

raw

Raw protobuf wire format.

tags

Tags for protobuf-specific types.

Structs

ProtoBufStream

An sval::Stream that encodes into the protobuf wire format.

ProtoBufStreamReusable

The re-usable internals of a ProtoBufStream that can optimize a later encoding.

Functions

stream_to_protobuf

Encode a value to the protobuf wire format.