1# Cargo2gn工具操作指导
2## 概述
3
4rust三方库使用cargo编译，配置为Cargo.toml。集成到OpenHarmony上需要转换成BUILD.gn规则。为了满足这个需求，需要提供一个cargo2gn转换工具。当需要引入rust三方crate时使用cargo2gn转换工具来把三方库的Cargo.toml转换成BUILD.gn规则。cargo2gn可以单个库进行转换，也可以多个库进行批量转换。
5
6##  单个库转换操作步骤
71. 进入到需要转化的rust三方库的目录下，比如需要转化bindgen。
8
9    ```
10    cd openharmony/third_party/rust/bindgen
11    ```
12
132. 创建配置文件cargo2gn.json，可以参考如下配置。
14
15    ```json
16    {
17        "copy-out": true,
18        "run": true,
19        "add-workspace": true,
20        "cargo-bin": "/mnt/xxx/openharmony/prebuilts/rustc/linux-x86_64/current/bin"
21    }
22    ```
23
243. 执行以下命令进行转换。
25
26   ```
27   python3 /mnt/xxx/openharmony/build/scripts/cargo2gn.py --config cargo2gn.json
28   ```
29
30   转换结果
31
32   ```
33   import("//build/templates/rust/ohos_cargo_crate.gni")
34
35   ohos_cargo_crate("lib") {
36       crate_name = "bindgen"
37       crate_type = "rlib"
38       crate_root = "./lib.rs"
39
40       sources = ["./lib.rs"]
41       edition = "2018"
42       cargo_pkg_version = "0.64.0"
43       cargo_pkg_authors = "Jyun-Yan You <jyyou.tw@gmail.com>,  Emilio Cobos Álvarez <emilio@crisal.io>,  Nick Fitzgerald <fitzgen@gmail.com>,  The Servo project developers"
44       cargo_pkg_name = "bindgen"
45       cargo_pkg_description = "Automatically generates Rust FFI bindings to C and C++ libraries."
46       deps = [
47           "//third_party/rust/bitflags:lib",
48           "//third_party/rust/cexpr:lib",
49           "//third_party/rust/clang-sys:lib",
50           "//third_party/rust/lazy_static:lib",
51           "//third_party/rust/lazycell:lib",
52           "//third_party/rust/log:lib",
53           "//third_party/rust/peeking_take_while:lib",
54           "//third_party/rust/proc-macro2:lib",
55           "//third_party/rust/quote:lib",
56           "//third_party/rust/regex:lib",
57           "//third_party/rust/rustc-hash:lib",
58           "//third_party/rust/shlex:lib",
59           "//third_party/rust/syn:lib",
60           "//third_party/rust/which:lib",
61       ]
62       features = [
63           "default",
64           "log",
65           "logging",
66           "static",
67           "which",
68           "which-rustfmt",
69       ]
70       build_root = "build.rs"
71       build_sources = ["build.rs"]
72       build_script_outputs = ["host-target.txt"]
73   }
74   ```
75
76
77
78##  多个库批量转换操作步骤
791. 进入到rust目录下。
80
81   ```
82   cd openharmony/third_party/rust
83   ```
842. 把所有需要转换的rust三方库添加到rust目录下的Cargo.toml的[workspace]里，如下所示。
85
86    ```toml
87    [workspace]
88    members = [
89        "aho-corasick",
90        "memchr",
91    ]
92    ```
933. 执行单个库转换操作步骤的2和3。
94
95