changes

src/rust-learn/napi-rs/1.导出class.md

@@ -0,0 +1,66 @@
+# 导出Class
+
+```rust
+use std::path::{Path, PathBuf};
+use napi_derive::napi;
+use tokio::{fs};
+use futures::prelude::*;
+use napi::bindgen_prelude::*;
+
+// 此处可以通过js_name制定类名
+#[napi(js_name = "ClassDemoName")]
+pub struct ClassDemo {
+  name: String
+}
+
+#[napi]
+impl ClassDemo {
+  // 设置当前的new方法为构造函数
+  #[napi(constructor)]
+  pub fn new() -> Self {
+    ClassDemo {
+      name: String::from("123")
+    }
+  }
+
+  // 设置一个工厂方法，必须返回当前的类, 最后会变成一个静态的方法，并且返回当前类的实例
+  #[napi(factory)]
+  pub fn with_initial_count(count: u32) -> ClassDemo {
+    ClassDemo {
+      name: String::from(count.to_string())
+    }
+  }
+
+  // 设置一个普通的异步方法
+  #[napi]
+  pub async fn read_dir(&self, query: String) -> napi::Result<String> {
+    let res = fs::read_to_string(PathBuf::from(query)).await?;
+    Ok(res)
+  }
+
+  // 设置一个普通方法
+  #[napi]
+  pub fn return_string(&self) -> napi::Result<String> {
+    Ok(String::from("value"))
+  }
+
+  // 设置一个getter
+  #[napi(getter)]
+  pub fn name(&self) -> &str {
+    self.name.as_str()
+  }
+
+  // 设置一个setter
+  #[napi(setter)]
+  pub fn set_name(&mut self, s: String) {
+    self.name = s;
+  }
+
+  // 设置方法的可访问性 writable / enumerable / configurable
+  #[napi(writable = false)]
+  pub fn get_name(&self) -> &str {
+    self.name.as_str()
+  }
+}
+```
+

src/rust-learn/napi-rs/2.导出异步函数.md

@@ -0,0 +1,25 @@
+# 导出异步函数
+
+```rust
+[dependencies]
+napi = { version = "2", features = ["async"] }
+```
+
+```rust
+use futures::prelude::*;
+use napi::bindgen_prelude::*;
+use tokio::fs;
+
+#[napi]
+async fn read_file_async(path: String) -> Result<Buffer> {
+  fs::read(path)
+    .map(|r| match r {
+      Ok(content) => Ok(content.into()),
+      Err(e) => Err(Error::new(
+        Status::GenericFailure,
+        format!("failed to read file, {}", e),
+      )),
+    })
+    .await
+}
+```

src/rust-learn/napi-rs/3.在rust中执行js的Promise.md

@@ -0,0 +1,23 @@
+# 在rust中执行js的Promise
+```rust
+use napi::bindgen_prelude::*;
+
+#[napi]
+pub async fn async_plus_100(p: Promise<u32>) -> Result<u32> {
+  let v = p.await?;
+  Ok(v + 100)
+}
+```
+
+```js
+import { asyncPlus100 } from './index.js'
+
+const fx = 20
+const result = await asyncPlus100(
+  new Promise((resolve) => {
+    setTimeout(() => resolve(fx), 50)
+  }),
+)
+
+console.log(result) // 120
+```

src/rust-learn/napi-rs/4.注入this用来获取js运行时设置的属性.md

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+# 注入this用来获取js运行时设置的属性
+
+## 在类中使用
+
+```js
+import { QueryEngine } from './index.js'
+
+const qe = new QueryEngine()
+qe.refCount = 3
+console.log(qe.getRefCount()) // 3
+```
+
+在上面的例子中， QueryEngine 并没有声明和初始化 refCount， 但是js动态设置了，rust要怎么做才能获取到这个属性呢？
+
+```rust
+#[napi]
+use napi::bindgen_prelude::*;
+use napi_derive::napi;
+
+pub struct QueryEngine {}
+
+#[napi]
+impl QueryEngine {
+  #[napi(constructor)]
+  pub fn new() -> Result<Self> {
+    Ok(Self {})
+  }
+
+  #[napi]
+  pub fn get_ref_count(&self, this: This) -> Result<Option<i32>> {
+    this.get::<i32>("refCount")
+  }
+}
+```
+
+
+
+
+## 在函数中使用
+```rust
+import { Width, plusOne } from './index.js'
+
+const width = new Width(1)
+console.log(plusOne(width)) // 2
+```
+在上面的例子中，plusOne可能有自己的this上下文
+
+```rust
+use napi::bindgen_prelude::*;
+use napi_derive::napi;
+
+#[napi(constructor)]
+pub struct Width {
+  pub value: i32,
+}
+
+#[napi]
+pub fn plus_one(this: This<&Width>) -> i32 {
+  this.value + 1
+}
+```

src/rust-learn/napi-rs/index.md

@@ -0,0 +1 @@
+# napi-rs