Add cargo2gn docs

Issue:I6SJNH
Signed-off-by: Nliuguangfeng <liuguangfeng2@huawei.com>
Change-Id: I11ad7ff3802cd810696d0f7cec6c3ed8d538fdf1

zh-cn/device-dev/subsystems/Readme-CN.md

@@ -18,6 +18,10 @@
       - [加快本地编译的一些参数](subsys-build-reference.md)
       - [查看NinjaTrace](subsys-build-reference.md)
       - [HAP编译构建指导](subsys-build-gn-hap-compilation-guide.md)
+      - Rust编译构建指导
+        - [Rust模块配置规则和指导](subsys-build-rust-compilation.md)
+        - [Bindgen、CXX工具使用指导](subsys-build-bindgen-cxx-guide.md)
+        - [Cargo2gn工具操作指导](subsys-build-cargo2gn-guide.md)
       - [ 常见问题](subsys-build-FAQ.md)
 - [ArkCompiler](subsys-arkcompiler-guide.md)
 - [分布式远程启动](subsys-remote-start.md)

zh-cn/device-dev/subsystems/subsys-build-cargo2gn-guide.md

+# Cargo2gn工具操作指导
+## 概述
+
+rust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。
+
+##  单个库转换操作步骤
+1. 进入到需要转化的rust三方库的目录下，比如需要转化bindgen。
+
+    ```
+    cd openharmony/third_party/rust/bindgen
+    ```
+    
+2. 创建配置文件cargo2gn.json，可以参考如下配置。
+
+    ```
+    {
+        "copy-out": true,
+        "run": true,
+        "add-workspace": true,
+        "cargo-bin": "/mnt/xxx/openharmony/prebuilts/rustc/linux-x86_64/current/bin"
+    }
+    ```
+    
+3. 执行以下命令进行转换。
+   
+   ```
+   python /mnt/xxx/openharmony/build/scripts/cargo2gn.py --config cargo2gn.json
+   ```
+   
+   转换结果
+   
+   ```
+   import("//build/templates/rust/ohos_cargo_crate.gni")
+   
+   ohos_cargo_crate("lib") {
+       crate_name = "bindgen"
+       crate_type = "rlib"
+       crate_root = "./lib.rs"
+   
+       sources = ["./lib.rs"]
+       edition = "2018"
+       cargo_pkg_version = "0.64.0"
+       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"
+       cargo_pkg_name = "bindgen"
+       cargo_pkg_description = "Automatically generates Rust FFI bindings to C and C++ libraries."
+       deps = [
+           "//third_party/rust/bitflags:lib",
+           "//third_party/rust/cexpr:lib",
+           "//third_party/rust/clang-sys:lib",
+           "//third_party/rust/lazy_static:lib",
+           "//third_party/rust/lazycell:lib",
+           "//third_party/rust/log:lib",
+           "//third_party/rust/peeking_take_while:lib",
+           "//third_party/rust/proc-macro2:lib",
+           "//third_party/rust/quote:lib",
+           "//third_party/rust/regex:lib",
+           "//third_party/rust/rustc-hash:lib",
+           "//third_party/rust/shlex:lib",
+           "//third_party/rust/syn:lib",
+           "//third_party/rust/which:lib",
+       ]
+       features = [
+           "default",
+           "log",
+           "logging",
+           "static",
+           "which",
+           "which-rustfmt",
+       ]
+       build_root = "build.rs"
+       build_sources = ["build.rs"]
+       build_script_outputs = ["host-target.txt"]
+   }
+   ```
+   
+   
+
+##  多个库批量转换操作步骤
+1. 进入到rust目录下。
+   
+   ```
+   cd openharmony/third_party/rust
+   ```
+2. 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。
+
+    ```
+    [workspace]
+    members = [
+        "aho-corasick",
+        "memchr",
+    ]
+    ```
+3. 执行单个库转换操作步骤的2和3。
+

zh-cn/device-dev/subsystems/subsys-build-module.md

@@ -23,6 +23,17 @@ ohos_app_scope
 ohos_js_assets
 ohos_resources
 
+#rust模板
+ohos_rust_executable
+ohos_rust_shared_library
+ohos_rust_static_library
+ohos_rust_proc_macro
+ohos_rust_shared_ffi
+ohos_rust_static_ffi
+ohos_rust_cargo_crate
+ohos_rust_systemtest
+ohos_rust_unittest
+
 #其他常用模板
 #配置文件
 ohos_prebuilt_etc
@@ -317,7 +328,9 @@ ohos_prebuilt_static_library("helloworld") {
 
 hap模板详见：[ HAP编译构建指导](https://gitee.com/openharmony/docs/blob/master/zh-cn/device-dev/subsystems/subsys-build-gn-hap-compilation-guide.md)
 
+### Rust模板
 
+rust模板详见：[ Rust模块配置规则和指导](https://gitee.com/openharmony/docs/blob/master/zh-cn/device-dev/subsystems/subsys-build-rust-compilation.md)
 
 ### 其他常用模板