prost/
lib.rs

1#![doc(html_root_url = "https://docs.rs/prost/0.12.6")]
2#![cfg_attr(not(feature = "std"), no_std)]
3#![doc = include_str!("../README.md")]
4
5// Re-export the alloc crate for use within derived code.
6#[doc(hidden)]
7pub extern crate alloc;
8
9// Re-export the bytes crate for use within derived code.
10pub use bytes;
11
12mod error;
13mod message;
14mod name;
15mod types;
16
17#[doc(hidden)]
18pub mod encoding;
19
20pub use crate::error::{DecodeError, EncodeError};
21pub use crate::message::Message;
22pub use crate::name::Name;
23
24use bytes::{Buf, BufMut};
25
26use crate::encoding::{decode_varint, encode_varint, encoded_len_varint};
27
28// See `encoding::DecodeContext` for more info.
29// 100 is the default recursion limit in the C++ implementation.
30#[cfg(not(feature = "no-recursion-limit"))]
31const RECURSION_LIMIT: u32 = 100;
32
33/// Encodes a length delimiter to the buffer.
34///
35/// See [Message.encode_length_delimited] for more info.
36///
37/// An error will be returned if the buffer does not have sufficient capacity to encode the
38/// delimiter.
39pub fn encode_length_delimiter<B>(length: usize, buf: &mut B) -> Result<(), EncodeError>
40where
41    B: BufMut,
42{
43    let length = length as u64;
44    let required = encoded_len_varint(length);
45    let remaining = buf.remaining_mut();
46    if required > remaining {
47        return Err(EncodeError::new(required, remaining));
48    }
49    encode_varint(length, buf);
50    Ok(())
51}
52
53/// Returns the encoded length of a length delimiter.
54///
55/// Applications may use this method to ensure sufficient buffer capacity before calling
56/// `encode_length_delimiter`. The returned size will be between 1 and 10, inclusive.
57pub fn length_delimiter_len(length: usize) -> usize {
58    encoded_len_varint(length as u64)
59}
60
61/// Decodes a length delimiter from the buffer.
62///
63/// This method allows the length delimiter to be decoded independently of the message, when the
64/// message is encoded with [Message.encode_length_delimited].
65///
66/// An error may be returned in two cases:
67///
68///  * If the supplied buffer contains fewer than 10 bytes, then an error indicates that more
69///    input is required to decode the full delimiter.
70///  * If the supplied buffer contains more than 10 bytes, then the buffer contains an invalid
71///    delimiter, and typically the buffer should be considered corrupt.
72pub fn decode_length_delimiter<B>(mut buf: B) -> Result<usize, DecodeError>
73where
74    B: Buf,
75{
76    let length = decode_varint(&mut buf)?;
77    if length > usize::max_value() as u64 {
78        return Err(DecodeError::new(
79            "length delimiter exceeds maximum usize value",
80        ));
81    }
82    Ok(length as usize)
83}
84
85// Re-export #[derive(Message, Enumeration, Oneof)].
86// Based on serde's equivalent re-export [1], but enabled by default.
87//
88// [1]: https://github.com/serde-rs/serde/blob/v1.0.89/serde/src/lib.rs#L245-L256
89#[cfg(feature = "derive")]
90#[allow(unused_imports)]
91#[macro_use]
92extern crate prost_derive;
93#[cfg(feature = "derive")]
94#[doc(hidden)]
95pub use prost_derive::*;
prost/lib.rs

prost/
lib.rs
