Make PacketReader/PacketWriter interfaces async-only.

blimp/net/stream_packet_reader.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "blimp/net/stream_packet_reader.h"
 
 #include <iostream>
 
 #include "base/callback_helpers.h"
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
 #include "base/sys_byteorder.h"
 #include "blimp/net/common.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/socket/stream_socket.h"
 
 namespace blimp {
 
 std::ostream& operator<<(std::ostream& out,
                          const StreamPacketReader::ReadState state) {
@@ skipping 13 matching lines @@
 
 StreamPacketReader::StreamPacketReader(net::StreamSocket* socket)
     : read_state_(ReadState::IDLE), socket_(socket), weak_factory_(this) {
   DCHECK(socket_);
   header_buffer_ = new net::GrowableIOBuffer;
   header_buffer_->SetCapacity(kPacketHeaderSizeBytes);
 }
 
 StreamPacketReader::~StreamPacketReader() {}
 
-int StreamPacketReader::ReadPacket(
+void StreamPacketReader::ReadPacket(
     const scoped_refptr<net::GrowableIOBuffer>& buf,
     const net::CompletionCallback& callback) {
   DCHECK_EQ(ReadState::IDLE, read_state_);
   DCHECK_GT(buf->capacity(), 0);
 
   header_buffer_->set_offset(0);
   payload_buffer_ = buf;
   payload_buffer_->set_offset(0);
   read_state_ = ReadState::HEADER;
 
   int result = DoReadLoop(net::OK);
-  if (result == net::ERR_IO_PENDING) {
-    // Store the completion callback to invoke when read completes
-    // asynchronously.
-    callback_ = callback;
-  } else {
+  if (result != net::ERR_IO_PENDING) {
     // Release the payload buffer, since the read operation has completed
     // synchronously.
     payload_buffer_ = nullptr;
+
+    // Adapt synchronous completion to an asynchronous style.
+    base::MessageLoop::current()->PostTask(FROM_HERE,
+                                           base::Bind(callback, result));
+  } else {
+    callback_ = callback;
   }
-
-  return result;
 }
 
 int StreamPacketReader::DoReadLoop(int result) {
   DCHECK_NE(net::ERR_IO_PENDING, result);
   DCHECK_GE(result, 0);
   DCHECK_NE(ReadState::IDLE, read_state_);
 
   while (result >= 0 && read_state_ != ReadState::IDLE) {
     VLOG(2) << "DoReadLoop (state=" << read_state_ << ", result=" << result
             << ")";
@@ skipping 69 matching lines @@
 
   // If all reading completed, either successfully or by error, inform the
   // caller.
   if (result != net::ERR_IO_PENDING) {
     payload_buffer_ = nullptr;
     base::ResetAndReturn(&callback_).Run(result);
   }
 }
 
 }  // namespace blimp