From 452e134a86944a787f3f50fc43f0f8f0890a1b17 Mon Sep 17 00:00:00 2001
From: Kai Mast <kaimast@cs.wisc.edu>
Date: Sun, 2 Jul 2023 17:34:49 -0400
Subject: [PATCH 1/3] Add read_to_end functionality

---
 src/fs/file.rs   | 27 +++++++++++++++++++++++++++
 src/io/write.rs  |  2 +-
 tests/fs_file.rs | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/src/fs/file.rs b/src/fs/file.rs
index 9cd47f21..e7e8a1c0 100644
--- a/src/fs/file.rs
+++ b/src/fs/file.rs
@@ -444,6 +444,33 @@ impl File {
         (Ok(()), buf.into_inner())
     }
 
+    /// Fills a vector with the contents of the file
+    /// from the given position to the end
+    ///
+    /// If this function encounters any form of I/O or other error, an error
+    /// variant will be returned.
+    /// On error the buffer will contain the partial data that was
+    /// read up until this point.
+    pub async fn read_at_to_end(&self, mut pos: u64, mut result: Vec<u8>) -> crate::BufResult<(), Vec<u8>> {
+        let mut buffer = vec![0u8; 1024];
+
+        loop {
+            let (res, buf) = self.read_at(buffer, pos).await;
+
+            match res {
+                Ok(0) => {
+                    return (Ok(()), result)
+                }
+                Ok(n) => {
+                    buffer = buf;
+                    result.extend_from_slice(&buffer[..n]);
+                    pos += n as u64;
+                }
+                Err(err) => return (Err(err), result),
+            }
+        }
+    }
+
     /// Like [`read_at`], but using a pre-mapped buffer
     /// registered with [`FixedBufRegistry`].
     ///
diff --git a/src/io/write.rs b/src/io/write.rs
index 9063282b..6c607f75 100644
--- a/src/io/write.rs
+++ b/src/io/write.rs
@@ -49,7 +49,7 @@ impl<T: BoundedBuf> UnsubmittedWrite<T> {
                 buf,
             },
             WriteTransform {
-                _phantom: PhantomData::default(),
+                _phantom: PhantomData,
             },
             opcode::Write::new(types::Fd(fd.raw_fd()), ptr, len as _)
                 .offset(offset as _)
diff --git a/tests/fs_file.rs b/tests/fs_file.rs
index 6ec14d43..08622834 100644
--- a/tests/fs_file.rs
+++ b/tests/fs_file.rs
@@ -37,6 +37,23 @@ fn basic_read() {
     });
 }
 
+#[test]
+fn read_exact_buf_too_long() {
+    tokio_uring::start(async {
+        let data = HELLO.repeat(1);
+        let buf = Vec::with_capacity(data.len() * 2);
+
+        let mut tempfile = tempfile();
+        tempfile.write_all(&data).unwrap();
+
+        let file = File::open(tempfile.path()).await.unwrap();
+        let (res, _buf) = file.read_exact_at(buf, 0).await;
+
+        assert!(res.is_err());
+        assert_eq!(res.unwrap_err().kind(), std::io::ErrorKind::UnexpectedEof);
+    });
+}
+
 #[test]
 fn basic_read_exact() {
     tokio_uring::start(async {
@@ -53,6 +70,23 @@ fn basic_read_exact() {
     });
 }
 
+#[test]
+fn basic_read_to_end() {
+    tokio_uring::start(async {
+        let data = HELLO.repeat(1);
+
+        let mut tempfile = tempfile();
+        tempfile.write_all(&data).unwrap();
+
+        let file = File::open(tempfile.path()).await.unwrap();
+
+        let buf = vec![];
+        let (res, buf) = file.read_at_to_end(0, buf).await;
+        res.unwrap();
+        assert_eq!(buf, data);
+    });
+}
+
 #[test]
 fn basic_write() {
     tokio_uring::start(async {

From 2a3bed72c339ce27f127dbc891b8c0f372967f01 Mon Sep 17 00:00:00 2001
From: Kai Mast <kaimast@cs.wisc.edu>
Date: Sun, 2 Jul 2023 17:40:53 -0400
Subject: [PATCH 2/3] Cargo fmt

---
 src/buf/fixed/plumbing/registry.rs |  2 +-
 src/fs/file.rs                     | 10 ++++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/buf/fixed/plumbing/registry.rs b/src/buf/fixed/plumbing/registry.rs
index ff8ffe30..4f88746e 100644
--- a/src/buf/fixed/plumbing/registry.rs
+++ b/src/buf/fixed/plumbing/registry.rs
@@ -74,7 +74,7 @@ impl<T: IoBufMut> Registry<T> {
     pub(crate) fn check_out(&mut self, index: usize) -> Option<CheckedOutBuf> {
         let state = self.states.get_mut(index)?;
         let BufState::Free { init_len } = *state else {
-            return None
+            return None;
         };
 
         *state = BufState::CheckedOut;
diff --git a/src/fs/file.rs b/src/fs/file.rs
index e7e8a1c0..c4e06378 100644
--- a/src/fs/file.rs
+++ b/src/fs/file.rs
@@ -451,16 +451,18 @@ impl File {
     /// variant will be returned.
     /// On error the buffer will contain the partial data that was
     /// read up until this point.
-    pub async fn read_at_to_end(&self, mut pos: u64, mut result: Vec<u8>) -> crate::BufResult<(), Vec<u8>> {
+    pub async fn read_at_to_end(
+        &self,
+        mut pos: u64,
+        mut result: Vec<u8>,
+    ) -> crate::BufResult<(), Vec<u8>> {
         let mut buffer = vec![0u8; 1024];
 
         loop {
             let (res, buf) = self.read_at(buffer, pos).await;
 
             match res {
-                Ok(0) => {
-                    return (Ok(()), result)
-                }
+                Ok(0) => return (Ok(()), result),
                 Ok(n) => {
                     buffer = buf;
                     result.extend_from_slice(&buffer[..n]);

From 660c7be14c64446d5c291422b56de5f5c982a9dd Mon Sep 17 00:00:00 2001
From: Kai Mast <kai@kaimast.com>
Date: Mon, 22 Jul 2024 11:09:44 -0700
Subject: [PATCH 3/3] Use larger buffer for read_to_end

---
 src/fs/file.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/fs/file.rs b/src/fs/file.rs
index c4e06378..bf3f561f 100644
--- a/src/fs/file.rs
+++ b/src/fs/file.rs
@@ -456,7 +456,7 @@ impl File {
         mut pos: u64,
         mut result: Vec<u8>,
     ) -> crate::BufResult<(), Vec<u8>> {
-        let mut buffer = vec![0u8; 1024];
+        let mut buffer = vec![0u8; 4096];
 
         loop {
             let (res, buf) = self.read_at(buffer, pos).await;