feat(http): add Decoder.try_read and Encoder.try_write

examples/hello.rs

@@ -3,11 +3,8 @@ extern crate hyper;
 extern crate env_logger;
 extern crate num_cpus;
 
-use std::io::Write;
-
-use hyper::{Decoder, Encoder, Next};
-use hyper::net::{HttpStream, HttpListener};
-use hyper::server::{Server, Handler, Request, Response};
+use hyper::{Decoder, Encoder, Next, HttpStream};
+use hyper::server::{Server, Handler, Request, Response, HttpListener};
 
 static PHRASE: &'static [u8] = b"Hello World!";
 

examples/server.rs

@@ -4,11 +4,8 @@ extern crate env_logger;
 #[macro_use]
 extern crate log;
 
-use std::io::{self, Read, Write};
-
-use hyper::{Get, Post, StatusCode, RequestUri, Decoder, Encoder, Next};
+use hyper::{Get, Post, StatusCode, RequestUri, Decoder, Encoder, HttpStream, Next};
 use hyper::header::ContentLength;
-use hyper::net::HttpStream;
 use hyper::server::{Server, Handler, Request, Response};
 
 struct Echo {
@@ -78,13 +75,13 @@ impl Handler<HttpStream> for Echo {
         match self.route {
             Route::Echo(ref body) => {
                 if self.read_pos < self.buf.len() {
-                    match transport.read(&mut self.buf[self.read_pos..]) {
-                        Ok(0) => {
+                    match transport.try_read(&mut self.buf[self.read_pos..]) {
+                        Ok(Some(0)) => {
                             debug!("Read 0, eof");
                             self.eof = true;
                             Next::write()
                         },
-                        Ok(n) => {
+                        Ok(Some(n)) => {
                             self.read_pos += n;
                             match *body {
                                 Body::Len(max) if max <= self.read_pos as u64 => {
@@ -94,12 +91,10 @@ impl Handler<HttpStream> for Echo {
                                 _ => Next::read_and_write()
                             }
                         }
-                        Err(e) => match e.kind() {
-                            io::ErrorKind::WouldBlock => Next::read_and_write(),
-                            _ => {
-                                println!("read error {:?}", e);
-                                Next::end()
-                            }
+                        Ok(None) => Next::read_and_write(),
+                        Err(e) => {
+                            println!("read error {:?}", e);
+                            Next::end()
                         }
                     }
                 } else {
@@ -137,18 +132,16 @@ impl Handler<HttpStream> for Echo {
             }
             Route::Echo(..) => {
                 if self.write_pos < self.read_pos {
-                    match transport.write(&self.buf[self.write_pos..self.read_pos]) {
-                        Ok(0) => panic!("write ZERO"),
-                        Ok(n) => {
+                    match transport.try_write(&self.buf[self.write_pos..self.read_pos]) {
+                        Ok(Some(0)) => panic!("write ZERO"),
+                        Ok(Some(n)) => {
                             self.write_pos += n;
                             Next::write()
                         }
-                        Err(e) => match e.kind() {
-                            io::ErrorKind::WouldBlock => Next::write(),
-                            _ => {
-                                println!("write error {:?}", e);
-                                Next::end()
-                            }
+                        Ok(None) => Next::write(),
+                        Err(e) => {
+                            println!("write error {:?}", e);
+                            Next::end()
                         }
                     }
                 } else if !self.eof {

src/http/mod.rs

@@ -72,6 +72,31 @@ impl<'a, T: Read> Decoder<'a, T> {
         Decoder(DecoderImpl::H1(decoder, transport))
     }
 
+    /// Read from the `Transport`.
+    #[inline]
+    pub fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+        match self.0 {
+            DecoderImpl::H1(ref mut decoder, ref mut transport) => {
+                decoder.decode(transport, buf)
+            }
+        }
+    }
+
+    /// Try to read from the `Transport`.
+    ///
+    /// This method looks for the `WouldBlock` error. If the read did not block,
+    /// a return value would be `Ok(Some(x))`. If the read would block,
+    /// this method would return `Ok(None)`.
+    #[inline]
+    pub fn try_read(&mut self, buf: &mut [u8]) -> io::Result<Option<usize>> {
+        match self.read(buf) {
+            Ok(n) => Ok(Some(n)),
+            Err(e) => match e.kind() {
+                io::ErrorKind::WouldBlock => Ok(None),
+                _ => Err(e)
+            }
+        }
+    }
 
     /// Get a reference to the transport.
     pub fn get_ref(&self) -> &T {
@@ -86,9 +111,42 @@ impl<'a, T: Transport> Encoder<'a, T> {
         Encoder(EncoderImpl::H1(encoder, transport))
     }
 
+    /// Write to the `Transport`.
+    #[inline]
+    pub fn write(&mut self, data: &[u8]) -> io::Result<usize> {
+        if data.is_empty() {
+            return Ok(0);
+        }
+        match self.0 {
+            EncoderImpl::H1(ref mut encoder, ref mut transport) => {
+                if encoder.is_closed() {
+                    Ok(0)
+                } else {
+                    encoder.encode(*transport, data)
+                }
+            }
+        }
+    }
+
+    /// Try to write to the `Transport`.
+    ///
+    /// This method looks for the `WouldBlock` error. If the write did not block,
+    /// a return value would be `Ok(Some(x))`. If the write would block,
+    /// this method would return `Ok(None)`.
+    #[inline]
+    pub fn try_write(&mut self, data: &[u8]) -> io::Result<Option<usize>> {
+        match self.write(data) {
+            Ok(n) => Ok(Some(n)),
+            Err(e) => match e.kind() {
+                io::ErrorKind::WouldBlock => Ok(None),
+                _ => Err(e)
+            }
+        }
+    }
+
     /// Closes an encoder, signaling that no more writing will occur.
     ///
-    /// This is needed for encodings that don't know length of the content
+    /// This is needed for encodings that don't know the length of the content
     /// beforehand. Most common instance would be usage of
     /// `Transfer-Enciding: chunked`. You would call `close()` to signal
     /// the `Encoder` should write the end chunk, or `0\r\n\r\n`.
@@ -109,29 +167,14 @@ impl<'a, T: Transport> Encoder<'a, T> {
 impl<'a, T: Read> Read for Decoder<'a, T> {
     #[inline]
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        match self.0 {
-            DecoderImpl::H1(ref mut decoder, ref mut transport) => {
-                decoder.decode(transport, buf)
-            }
-        }
+        self.read(buf)
     }
 }
 
 impl<'a, T: Transport> Write for Encoder<'a, T> {
     #[inline]
     fn write(&mut self, data: &[u8]) -> io::Result<usize> {
-        if data.is_empty() {
-            return Ok(0);
-        }
-        match self.0 {
-            EncoderImpl::H1(ref mut encoder, ref mut transport) => {
-                if encoder.is_closed() {
-                    Ok(0)
-                } else {
-                    encoder.encode(*transport, data)
-                }
-            }
-        }
+        self.write(data)
     }
 
     #[inline]