From 6ea5aa1a9b7e131f43fbf0979e2f2ee956a5d722 Mon Sep 17 00:00:00 2001
From: ZhangJianxin <zhangjianxin23@huawei.com>
Date: Thu, 8 May 2025 09:20:02 +0800
Subject: [PATCH] add AsyncSeek for &File

Signed-off-by: ZhangJianxin <zhangjianxin23@huawei.com>
Change-Id: I99385e61a70f94a2349c7bd6cde16f9a47a85c0f
---
 ylong_runtime/src/fs/async_file.rs | 56 ++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/ylong_runtime/src/fs/async_file.rs b/ylong_runtime/src/fs/async_file.rs
index d974887..323954f 100644
--- a/ylong_runtime/src/fs/async_file.rs
+++ b/ylong_runtime/src/fs/async_file.rs
@@ -522,6 +522,62 @@ impl AsyncSeek for File {
     }
 }
 
+impl AsyncSeek for &File {
+    fn poll_seek(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        mut pos: SeekFrom,
+    ) -> Poll<io::Result<u64>> {
+        let file = self.get_mut();
+        let mut inner = match file.inner.try_lock() {
+            Ok(inner) => inner,
+            Err(e) => return Poll::Ready(Err(io::Error::other(e))),
+        };
+        loop {
+            match inner.state {
+                FileState::Idle(ref mut buf) => {
+                    // after each take, buf will be set right back
+                    let mut r_buf = buf.take().unwrap();
+
+                    // move the cursor back since there's unread data in the buf
+                    let unread = r_buf.drop_unread();
+                    if unread != 0 {
+                        if let SeekFrom::Current(ref mut idx) = pos {
+                            *idx -= unread
+                        }
+                    }
+
+                    let file = file.file.clone();
+                    inner.state =
+                        FileState::Seeking(spawn_blocking(&TaskBuilder::new(), move || {
+                            let ret = (&*file).seek(pos);
+                            (r_buf, ret)
+                        }));
+                }
+                ref mut state => {
+                    let op = state.get_op();
+                    let res = poll_ready!(Pin::new(state).poll(cx));
+                    match op {
+                        FileOp::Reading => {}
+                        FileOp::Writing => {
+                            if let Err(e) = res {
+                                // Save the error for the next write.
+                                inner.write_err = Some(e.kind());
+                            }
+                        }
+                        FileOp::Seeking => {
+                            if let Ok(idx) = res {
+                                inner.idx = idx;
+                            }
+                            return Poll::Ready(res);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
 impl AsyncRead for File {
     fn poll_read(
         self: Pin<&mut Self>,
-- 
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