更多注释

3 files changed, 23 insertions, 11 deletions

diff --git a/monoio/src/driver/legacy/mod.rs b/monoio/src/driver/legacy/mod.rs
index 483cd70..350a754 100644
--- a/monoio/src/driver/legacy/mod.rs
+++ b/monoio/src/driver/legacy/mod.rs
@@ -279,6 +279,7 @@ impl LegacyInner {
 
         // wait io ready and do syscall
         // 等待 io 准备就绪并执行系统调用
+        // index 是 io 的 唯一标识吗...
         let mut scheduled_io = inner.io_dispatch.get(index).expect("scheduled_io lost");
         let ref_mut = scheduled_io.as_mut();
         loop {
@@ -295,18 +296,21 @@ impl LegacyInner {
                     flags: 0,
                 });
             }
-
+            // system call
             match OpAble::legacy_call(data) {
+                // io 读取结果成功
                 Ok(n) => {
                     return Poll::Ready(CompletionMeta {
                         result: Ok(n),
                         flags: 0,
                     })
                 }
+                // io 未就绪
                 Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
-                    ref_mut.clear_readiness(direction.mask());
-                    continue;
+                    ref_mut.clear_readiness(direction.mask()); // 清理就绪状态
+                    continue; // 跳过此轮循环
                 }
+                // 出错
                 Err(e) => {
                     return Poll::Ready(CompletionMeta {
                         result: Err(e),
diff --git a/monoio/src/driver/legacy/scheduled_io.rs b/monoio/src/driver/legacy/scheduled_io.rs
index 41d901f..5ace84f 100644
--- a/monoio/src/driver/legacy/scheduled_io.rs
+++ b/monoio/src/driver/legacy/scheduled_io.rs
@@ -7,8 +7,10 @@ pub(crate) struct ScheduledIo {
     readiness: Ready, // IO 的状态
 
     /// Waker used for AsyncRead.
+    /// 读取的 waker
     reader: Option<Waker>,
     /// Waker used for AsyncWrite.
+    /// 写入的 waker
     writer: Option<Waker>,
 }
 
@@ -23,15 +25,16 @@ impl Default for ScheduledIo {
 }
 
 impl ScheduledIo {
+    // 设置可写
     #[allow(unused)]
     pub(crate) fn set_writable(&mut self) {
         self.readiness |= Ready::WRITABLE;
     }
-
+    // 设置可读
     pub(crate) fn set_readiness(&mut self, f: impl Fn(Ready) -> Ready) {
         self.readiness = f(self.readiness);
     }
-
+    // 唤醒
     pub(crate) fn wake(&mut self, ready: Ready) {
         if ready.is_readable() {
             if let Some(waker) = self.reader.take() {
@@ -44,7 +47,7 @@ impl ScheduledIo {
             }
         }
     }
-
+    // 清理状态
     pub(crate) fn clear_readiness(&mut self, ready: Ready) {
         self.readiness = self.readiness - ready;
     }
@@ -53,26 +56,31 @@ impl ScheduledIo {
     pub(crate) fn poll_readiness(
         &mut self,
         cx: &mut Context<'_>,
-        direction: Direction,
+        direction: Direction, // read or write
     ) -> Poll<Ready> {
         let ready = direction.mask() & self.readiness;
+        // 如果已经准备好了，直接返回
         if !ready.is_empty() {
             return Poll::Ready(ready);
         }
+        // 根据 direction 取 waker
         let slot = match direction {
             Direction::Read => &mut self.reader,
             Direction::Write => &mut self.writer,
         };
         match slot {
+            // waker 存在
             Some(existing) => {
+                // 如果 slot 的 waker 和 cx.waker 唤醒的不是同一个 task，更新 waker
                 if !existing.will_wake(cx.waker()) {
                     *existing = cx.waker().clone();
                 }
             }
             None => {
+                // waker 不存在，设置 waker
                 *slot = Some(cx.waker().clone());
             }
         }
-        Poll::Pending
+        Poll::Pending // 返回 Pending
     }
 }
diff --git a/monoio/src/driver/op.rs b/monoio/src/driver/op.rs
index 979f35a..60ef587 100644
--- a/monoio/src/driver/op.rs
+++ b/monoio/src/driver/op.rs
@@ -40,7 +40,7 @@ pub(crate) struct Op<T: 'static> {
 #[derive(Debug)]
 pub(crate) struct Completion<T> {
     pub(crate) data: T,              // 返回的数据
-    pub(crate) meta: CompletionMeta, // 操作状态?
+    pub(crate) meta: CompletionMeta, // 操作状态
 }
 
 /// Operation completion meta info.
@@ -57,9 +57,9 @@ pub(crate) trait OpAble {
     fn uring_op(&mut self) -> io_uring::squeue::Entry;
 
     #[cfg(feature = "legacy")]
-    fn legacy_interest(&self) -> Option<(super::legacy::ready::Direction, usize)>;
+    fn legacy_interest(&self) -> Option<(super::legacy::ready::Direction, usize)>; // 获取 io 事件
     #[cfg(feature = "legacy")]
-    fn legacy_call(&mut self) -> io::Result<u32>;
+    fn legacy_call(&mut self) -> io::Result<u32>; // system call
 }
 
 /// If legacy is enabled and iouring is not, we can expose io interface in a poll-like way.