From 8ddaf1e4e333a2fe8e324f035e7036e8db82a3e1 Mon Sep 17 00:00:00 2001
From: Titouan Rigoudy <titouan.rigoudy@gmail.com>
Date: Tue, 3 May 2016 11:16:27 +0200
Subject: [PATCH] Move SendPacket out of Parser and into Stream.

---
 src/proto/stream.rs | 92 ++++++++++++++++++++++-----------------------
 1 file changed, 45 insertions(+), 47 deletions(-)

diff --git a/src/proto/stream.rs b/src/proto/stream.rs
index 8579b93..b83772a 100644
--- a/src/proto/stream.rs
+++ b/src/proto/stream.rs
@@ -15,15 +15,6 @@ use super::packet::{MutPacket, Packet, ReadFromPacket, WriteToPacket};
  * PARSER *
  *========*/
 
-/// This trait is implemented by packet sinks to which a parser can forward
-/// the packets it reads.
-pub trait SendPacket {
-    type Value: ReadFromPacket;
-    type Error: error::Error;
-
-    fn send_packet(&mut self, Self::Value) -> Result<(), Self::Error>;
-}
-
 /// This enum defines the possible states of a packet parser state machine.
 #[derive(Debug, Clone, Copy)]
 enum State {
@@ -36,20 +27,18 @@ enum State {
 }
 
 #[derive(Debug)]
-struct Parser<T: SendPacket> {
+struct Parser {
     state:          State,
     num_bytes_left: usize,
     buffer:         Vec<u8>,
-    packet_tx:      T,
 }
 
-impl<T: SendPacket> Parser<T> {
-    pub fn new(packet_tx: T) -> Self {
+impl Parser {
+    pub fn new() -> Self {
         Parser {
             state:          State::ReadingLength,
             num_bytes_left: U32_SIZE,
             buffer:         vec![0; U32_SIZE],
-            packet_tx:      packet_tx,
         }
     }
 
@@ -62,7 +51,7 @@ impl<T: SendPacket> Parser<T> {
     /// Note: as long as this function returns `Ok(Some(p))`, the caller is
     /// responsible for calling it once more to ensure that all packets are
     /// read as soon as possible.
-    fn try_read<U>(&mut self, stream: &mut U) -> io::Result<Option<Packet>>
+    pub fn try_read<U>(&mut self, stream: &mut U) -> io::Result<Option<Packet>>
         where U: io::Read
     {
         // Try to read as many bytes as we currently need from the underlying
@@ -72,7 +61,6 @@ impl<T: SendPacket> Parser<T> {
             None => (),
 
             Some(num_bytes_read) => {
-                assert!(num_bytes_read <= self.num_bytes_left);
                 self.num_bytes_left -= num_bytes_read;
             },
         }
@@ -110,31 +98,6 @@ impl<T: SendPacket> Parser<T> {
             }
         }
     }
-
-    pub fn read_from<U: io::Read>(&mut self, stream: &mut U) ->
-        Result<(), String>
-    {
-        loop {
-            let mut packet = match self.try_read(stream) {
-                Ok(Some(packet)) => packet,
-                Ok(None) => {
-                    return Ok(())
-                },
-                Err(e) => {
-                    return Err(format!("Error reading stream: {}", e))
-                }
-            };
-            let value = match packet.read_value() {
-                Ok(value) => value,
-                Err(e) => {
-                    return Err(format!("Error parsing packet: {}", e))
-                }
-            };
-            if let Err(e) = self.packet_tx.send_packet(value) {
-                return Err(format!("Error sending parsed packet: {}", e))
-            }
-        }
-    }
 }
 
 /*========*
@@ -183,6 +146,15 @@ impl OutBuf {
  * STREAM *
  *========*/
 
+/// This trait is implemented by packet sinks to which a stream can forward
+/// the packets it reads.
+pub trait SendPacket {
+    type Value: ReadFromPacket;
+    type Error: error::Error;
+
+    fn send_packet(&mut self, Self::Value) -> Result<(), Self::Error>;
+}
+
 /// This enum defines the possible actions the stream wants to take after
 /// processing an event.
 #[derive(Debug, Clone, Copy)]
@@ -201,9 +173,10 @@ pub struct Stream<T, U>
     where T: io::Read + io::Write + mio::Evented,
           U: SendPacket
 {
-    stream: T,
-    parser: Parser<U>,
+    parser: Parser,
     queue:  VecDeque<OutBuf>,
+    sender: U,
+    stream: T,
 }
 
 impl<T, U> Stream<T, U>
@@ -212,11 +185,12 @@ impl<T, U> Stream<T, U>
 {
     /// Returns a new struct wrapping the provided byte stream, which will
     /// forward packets to the provided sink.
-    pub fn new(stream: T, packet_tx: U) -> Self {
+    pub fn new(stream: T, sender: U) -> Self {
         Stream {
-            stream: stream,
-            parser: Parser::new(packet_tx),
+            parser: Parser::new(),
             queue:  VecDeque::new(),
+            sender: sender,
+            stream: stream,
         }
     }
 
@@ -226,6 +200,30 @@ impl<T, U> Stream<T, U>
         &self.stream
     }
 
+    fn on_readable(&mut self) -> Result<(), String> {
+        loop {
+            let mut packet = match self.parser.try_read(&mut self.stream) {
+                Ok(Some(packet)) => packet,
+                Ok(None) => {
+                    break
+                },
+                Err(e) => {
+                    return Err(format!("Error reading stream: {}", e))
+                }
+            };
+            let value = match packet.read_value() {
+                Ok(value) => value,
+                Err(e) => {
+                    return Err(format!("Error parsing packet: {}", e))
+                }
+            };
+            if let Err(e) = self.sender.send_packet(value) {
+                return Err(format!("Error sending parsed packet: {}", e))
+            }
+        }
+        Ok(())
+    }
+
     fn on_writable(&mut self) -> io::Result<()> {
         loop {
             let mut outbuf = match self.queue.pop_front() {
@@ -253,7 +251,7 @@ impl<T, U> Stream<T, U>
     /// The stream is ready to read, write, or both.
     pub fn on_ready(&mut self, event_set: mio::EventSet) -> Intent {
         if event_set.is_readable() {
-            let result = self.parser.read_from(&mut self.stream);
+            let result = self.on_readable();
             if let Err(e) = result {
                 error!("Stream input error: {}", e);
                 return Intent::Done