1# Rust third-party code 2 3This directory contains all third-party Rust code, and sometimes thin wrappers 4around it for C++ intertop. 5 6## Crates.io 7 8Crates that come from [crates.io](https://crates.io) are found in 9`//third_party/rust/chromium_crates_io`, and are all vendored into the 10Chromium git repository. They are managed through Cargo rules and with 11the `gnrt` tool. See [`//docs/rust.md`](../../docs/rust.md) for how to 12bring in new third-party libraries or update them. 13 14The GN rules and README.chromium files for these crates are written by 15the `gnrt` tool and should not be edited by hand. 16 17### Directory structure 18 19We store GN rules for each third-party crate in a directory of the same name. 20Under that directory a folder named based on the crate epoch version is 21created. This limits first-party usage of a crate to only one version within 22each epoch. 23If the crate's version has a major version greater-than 0, then that is used 24as its version folder, such as `v1`. Otherwise, the name includes all 25leading zeros in the version, such as `v0_3`. 26 27For example, GN rules for the `tutelage` crate at version **1.4.3** would be 28stored at 29```sh 30//third_party/rust/tutelage/v1 31``` 32 33Whereas GN rules for the verion **0.2.8** version would be stored at 34```sh 35//third_party/rust/tutelage/v0_2 36``` 37 38## Other sources 39 40Third-party Rust libraries that are not distributed through [crates.io]( 41https://crates.io) are uncommon. But they may live under 42`//third_party/rust/crate_name` or `//third_party/project_name` directly, 43as a git submodule, with GN rules written for them by hand 44(such GN rules would most likely use either the `cargo_crate("foo")` or the 45`rust_static_library("foo")` template from Chromium's `//build/rust/*.gni`). 46 47## OWNERS 48 49We do not require OWNERS in each crate's directory at this time, but this 50will be revisited in the future. 51 52## Review process 53 54Rust libraries must go through the [3rd-party review process]( 55../../docs/adding_to_third_party.md). 56See the [review of the `toml` crate]( 57https://groups.google.com/u/1/a/chromium.org/g/security/c/K686pSg-gZc/m/Pn2QzqahAwAJ) 58for an example of a Rust security review. 59