refactor(http): remove buffer, use WriteBuf

src/http/buf.rs

@@ -85,9 +85,7 @@ impl MemBuf {
             trace!("MemBuf::reserve unique access, growing");
             unsafe {
                 let mut vec = &mut *self.buf.get();
-                vec.reserve(needed);
-                let new_cap = vec.capacity();
-                grow_zerofill(vec, new_cap - orig_cap);
+                grow_zerofill(vec, needed);
             }
         } else {
             // we need to allocate more space, but dont have unique
@@ -139,9 +137,32 @@ impl MemBuf {
 
 #[inline]
 unsafe fn grow_zerofill(buf: &mut Vec<u8>, additional: usize) {
-    let len = buf.len();
-    buf.set_len(len + additional);
-    ::std::ptr::write_bytes(buf.as_mut_ptr().offset(len as isize), 0, additional);
+    let orig_cap = buf.capacity();
+    buf.reserve(additional);
+    let new_cap = buf.capacity();
+    let reserved = new_cap - orig_cap;
+    let orig_len = buf.len();
+    zero(buf, orig_len, reserved);
+    buf.set_len(orig_len + reserved);
+
+
+    unsafe fn zero(buf: &mut Vec<u8>, offset: usize, len: usize) {
+        assert!(buf.capacity() >= len + offset,
+            "offset of {} with len of {} is bigger than capacity of {}",
+            offset, len, buf.capacity());
+        ptr::write_bytes(buf.as_mut_ptr().offset(offset as isize), 0, len);
+    }
+}
+
+#[test]
+fn test_grow_zerofill() {
+    for init in 0..100 {
+        for reserve in (0..100).rev() {
+            let mut vec = vec![0; init];
+            unsafe { grow_zerofill(&mut vec, reserve) }
+            assert_eq!(vec.len(), vec.capacity());
+        }
+    }
 }
 
 impl fmt::Debug for MemBuf {

src/http/buffer.rs

@@ -1,107 +0,0 @@
-use std::cmp;
-use std::io::{self, Write};
-use std::ptr;
-
-
-const INIT_BUFFER_SIZE: usize = 4096;
-pub const MAX_BUFFER_SIZE: usize = 8192 + 4096 * 100;
-
-#[derive(Debug, Default)]
-pub struct Buffer {
-    vec: Vec<u8>,
-    tail: usize,
-    head: usize,
-}
-
-impl Buffer {
-    pub fn new() -> Buffer {
-        Buffer::default()
-    }
-
-    #[inline]
-    pub fn len(&self) -> usize {
-        self.tail - self.head
-    }
-
-    #[inline]
-    fn available(&self) -> usize {
-        self.vec.len() - self.tail
-    }
-
-    #[inline]
-    pub fn is_empty(&self) -> bool {
-        self.len() == 0
-    }
-
-    pub fn write_into<W: Write>(&mut self, w: &mut W) -> io::Result<usize> {
-        if self.is_empty() {
-            Ok(0)
-        } else {
-            let n = try!(w.write(&mut self.vec[self.head..self.tail]));
-            self.head += n;
-            self.maybe_reset();
-            Ok(n)
-        }
-    }
-
-    pub fn write(&mut self, data: &[u8]) -> usize {
-        trace!("Buffer::write len = {:?}", data.len());
-        self.maybe_reserve(data.len());
-        let len = cmp::min(self.available(), data.len());
-        assert!(self.available() >= len);
-        unsafe {
-            // in rust 1.9, we could use slice::copy_from_slice
-            ptr::copy(
-                data.as_ptr(),
-                self.vec.as_mut_ptr().offset(self.tail as isize),
-                len
-            );
-        }
-        self.tail += len;
-        len
-    }
-
-    #[inline]
-    fn maybe_reserve(&mut self, needed: usize) {
-        let cap = self.vec.len();
-        if cap == 0 {
-            // first reserve
-            let init = cmp::max(INIT_BUFFER_SIZE, needed);
-            trace!("reserving initial {}", init);
-            self.vec = vec![0; init];
-        } else if self.head > 0  && self.tail == cap && self.head >= needed {
-            // there is space to shift over
-            let count = self.tail - self.head;
-            trace!("moving buffer bytes over by {}", count);
-            unsafe {
-                ptr::copy(
-                    self.vec.as_ptr().offset(self.head as isize),
-                    self.vec.as_mut_ptr(),
-                    count
-                );
-            }
-            self.tail -= count;
-            self.head = 0;
-        } else if self.tail == cap && cap < MAX_BUFFER_SIZE {
-            self.vec.reserve(cmp::min(cap * 4, MAX_BUFFER_SIZE) - cap);
-            let new = self.vec.capacity() - cap;
-            trace!("reserved {}", new);
-            unsafe { grow_zerofill(&mut self.vec, new) }
-        }
-    }
-
-    #[inline]
-    fn maybe_reset(&mut self) {
-        if self.tail != 0 && self.tail == self.head {
-            self.tail = 0;
-            self.head = 0;
-        }
-    }
-}
-
-#[inline]
-unsafe fn grow_zerofill(buf: &mut Vec<u8>, additional: usize) {
-    let len = buf.len();
-    buf.set_len(len + additional);
-    ptr::write_bytes(buf.as_mut_ptr().offset(len as isize), 0, additional);
-}

src/http/conn.rs

@@ -610,12 +610,14 @@ mod tests {
 
     #[test]
     fn test_conn_body_write_length() {
+        extern crate pretty_env_logger;
         use ::futures::Future;
+        let _ = pretty_env_logger::init();
         let _: Result<(), ()> = ::futures::lazy(|| {
             let io = AsyncIo::new_buf(vec![], 0);
             let mut conn = Conn::<_, ServerTransaction>::new(io, Default::default());
-            let max = ::http::buffer::MAX_BUFFER_SIZE + 4096;
-            conn.state.writing = Writing::Body(Encoder::length(max as u64), None);
+            let max = ::http::io::MAX_BUFFER_SIZE + 4096;
+            conn.state.writing = Writing::Body(Encoder::length((max * 2) as u64), None);
 
             assert!(conn.start_send(Frame::Body { chunk: Some(vec![b'a'; 1024 * 4].into()) }).unwrap().is_ready());
             match conn.state.writing {
@@ -623,7 +625,7 @@ mod tests {
                 _ => panic!("writing did not queue chunk: {:?}", conn.state.writing),
             }
 
-            assert!(conn.start_send(Frame::Body { chunk: Some(vec![b'b'; max - 8192].into()) }).unwrap().is_ready());
+            assert!(conn.start_send(Frame::Body { chunk: Some(vec![b'b'; max].into()) }).unwrap().is_ready());
 
             match conn.state.writing {
                 Writing::Body(_, Some(_)) => {},
@@ -636,7 +638,8 @@ mod tests {
             assert!(conn.poll_complete().unwrap().is_not_ready());
             conn.io.io_mut().block_in(1024 * 3);
             assert!(conn.poll_complete().unwrap().is_not_ready());
-            conn.io.io_mut().block_in(max);
+            conn.io.io_mut().block_in(max * 2);
+            assert!(conn.poll_complete().unwrap().is_not_ready());
             assert!(conn.poll_complete().unwrap().is_ready());
 
             assert!(conn.start_send(Frame::Body { chunk: Some(vec![b'c'; 1024 * 4].into()) }).unwrap().is_ready());

src/http/io.rs

@@ -1,12 +1,13 @@
+use std::cmp;
 use std::fmt;
 use std::io::{self, Read, Write};
+use std::ptr;
 
 use futures::Async;
 use tokio::io::Io;
 
 use http::{Http1Transaction, h1, MessageHead, ParseResult};
 use http::buf::{MemBuf, MemSlice};
-use http::buffer::Buffer;
 
 const INIT_BUFFER_SIZE: usize = 4096;
 pub const MAX_BUFFER_SIZE: usize = 8192 + 4096 * 100;
@@ -14,7 +15,7 @@ pub const MAX_BUFFER_SIZE: usize = 8192 + 4096 * 100;
 pub struct Buffered<T> {
     io: T,
     read_buf: MemBuf,
-    write_buf: Buffer,
+    write_buf: WriteBuf,
 }
 
 impl<T> fmt::Debug for Buffered<T> {
@@ -31,7 +32,7 @@ impl<T: Io> Buffered<T> {
         Buffered {
             io: io,
             read_buf: MemBuf::new(),
-            write_buf: Buffer::new(),
+            write_buf: WriteBuf::new(),
         }
     }
 
@@ -91,7 +92,7 @@ impl<T: Io> Buffered<T> {
     }
 
     pub fn buffer<B: AsRef<[u8]>>(&mut self, buf: B) {
-        self.write_buf.write(buf.as_ref());
+        self.write_buf.buffer(buf.as_ref());
     }
 
     #[cfg(test)]
@@ -121,12 +122,12 @@ impl<T: Read> Read for Buffered<T> {
 
 impl<T: Write> Write for Buffered<T> {
     fn write(&mut self, data: &[u8]) -> io::Result<usize> {
-        Ok(self.write_buf.write(data))
+        Ok(self.write_buf.buffer(data))
     }
 
     fn flush(&mut self) -> io::Result<()> {
         self.write_buf.write_into(&mut self.io).and_then(|_n| {
-            if self.write_buf.is_empty() {
+            if self.write_buf.remaining() == 0 {
                 Ok(())
             } else {
                 Err(io::Error::new(io::ErrorKind::WouldBlock, "wouldblock"))
@@ -177,14 +178,20 @@ impl<T: AsRef<[u8]>> Cursor<T> {
         self.pos >= self.bytes.as_ref().len()
     }
 
-    /*
     pub fn write_to<W: Write>(&mut self, dst: &mut W) -> io::Result<usize> {
-        dst.write(&self.bytes.as_ref()[self.pos..]).map(|n| {
-            self.pos += n;
-            n
-        })
+        if self.remaining() == 0 {
+            Ok(0)
+        } else {
+            dst.write(&self.bytes.as_ref()[self.pos..]).map(|n| {
+                self.pos += n;
+                n
+            })
+        }
+    }
+
+    fn remaining(&self) -> usize {
+        self.bytes.as_ref().len() - self.pos
     }
-    */
 
     #[inline]
     pub fn buf(&self) -> &[u8] {
@@ -201,8 +208,15 @@ impl<T: AsRef<[u8]>> Cursor<T> {
 impl<T: AsRef<[u8]>> fmt::Debug for Cursor<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let bytes = self.buf();
-        let reasonable_max = ::std::cmp::min(bytes.len(), 32);
-        write!(f, "Cursor({:?})", &bytes[..reasonable_max])
+        if bytes.len() > 32 {
+            try!(f.write_str("Cursor(["));
+            for byte in &bytes[..32] {
+                try!(write!(f, "{:?}, ", byte));
+            }
+            write!(f, "... {}])", bytes.len())
+        } else {
+            write!(f, "Cursor({:?})", &bytes)
+        }
     }
 }
 
@@ -230,6 +244,66 @@ impl<T: Write> AtomicWrite for T {
 }
 //}
 
+// an internal buffer to collect writes before flushes
+#[derive(Debug)]
+struct WriteBuf(Cursor<Vec<u8>>);
+
+impl WriteBuf {
+    fn new() -> WriteBuf {
+        WriteBuf(Cursor::new(Vec::new()))
+    }
+
+    fn write_into<W: Write>(&mut self, w: &mut W) -> io::Result<usize> {
+        self.0.write_to(w)
+    }
+
+    fn buffer(&mut self, data: &[u8]) -> usize {
+        trace!("WriteBuf::buffer() len = {:?}", data.len());
+        self.maybe_reset();
+        self.maybe_reserve(data.len());
+        let mut vec = &mut self.0.bytes;
+        let len = cmp::min(vec.capacity() - vec.len(), data.len());
+        assert!(vec.capacity() - vec.len() >= len);
+        unsafe {
+            // in rust 1.9, we could use slice::copy_from_slice
+            ptr::copy(
+                data.as_ptr(),
+                vec.as_mut_ptr().offset(vec.len() as isize),
+                len
+            );
+            let new_len = vec.len() + len;
+            vec.set_len(new_len);
+        }
+        len
+    }
+
+    fn remaining(&self) -> usize {
+        self.0.remaining()
+    }
+
+    #[inline]
+    fn maybe_reserve(&mut self, needed: usize) {
+        let mut vec = &mut self.0.bytes;
+        let cap = vec.capacity();
+        if cap == 0 {
+            let init = cmp::max(INIT_BUFFER_SIZE, needed);
+            trace!("WriteBuf reserving initial {}", init);
+            vec.reserve(init);
+        } else if cap < MAX_BUFFER_SIZE {
+            vec.reserve(cmp::min(needed, MAX_BUFFER_SIZE - cap));
+            trace!("WriteBuf reserved {}", vec.capacity() - cap);
+        }
+    }
+
+    fn maybe_reset(&mut self) {
+        if self.0.pos != 0 && self.0.remaining() == 0 {
+            self.0.pos = 0;
+            unsafe {
+                self.0.bytes.set_len(0);
+            }
+        }
+    }
+}
 
 #[test]
 fn test_iobuf_write_empty_slice() {

src/http/mod.rs

@@ -16,7 +16,6 @@ pub use self::chunk::Chunk;
 
 mod body;
 mod buf;
-mod buffer;
 mod chunk;
 mod conn;
 mod io;

src/mock.rs

@@ -105,6 +105,7 @@ impl<T: Write> Write for AsyncIo<T> {
         } else if self.bytes_until_block == 0 {
             Err(io::Error::new(io::ErrorKind::WouldBlock, "mock block"))
         } else {
+            trace!("AsyncIo::write() block_in = {}, data.len() = {}", self.bytes_until_block, data.len());
             let n = cmp::min(self.bytes_until_block, data.len());
             let n = try!(self.inner.write(&data[..n]));
             self.bytes_until_block -= n;