Factor out the QUIC socket reading code into a stand alone QuicPacketReader

net/quic/quic_packet_reader.cc

+// Copyright (c) 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 "net/quic/quic_packet_reader.h"
+
+#include "base/metrics/histogram.h"
+#include "net/base/net_errors.h"
+
+namespace net {
+
+QuicPacketReader::QuicPacketReader(DatagramClientSocket* socket,
+                                   Visitor* visitor,
+                                   const BoundNetLog& net_log)
+    : socket_(socket),
+      visitor_(visitor),
+      read_pending_(false),
+      num_packets_read_(0),
+      read_buffer_(new IOBufferWithSize(kMaxPacketSize)),
+      net_log_(net_log),
+      weak_factory_(this) {
+}
+
+QuicPacketReader::~QuicPacketReader() {
+}
+
+void QuicPacketReader::StartReading() {
+  if (read_pending_)
+    return;
+
+  DCHECK(socket_);
+  read_pending_ = true;
+  int rv = socket_->Read(read_buffer_.get(), read_buffer_->size(),
+                         base::Bind(&QuicPacketReader::OnReadComplete,
+                                    weak_factory_.GetWeakPtr()));
+  UMA_HISTOGRAM_BOOLEAN("Net.QuicSession.AsyncRead", rv == ERR_IO_PENDING);
+  if (rv == ERR_IO_PENDING) {
+    num_packets_read_ = 0;
+    return;
+  }
+
+  if (++num_packets_read_ > 32) {
+    num_packets_read_ = 0;
+    // Data was read, process it.
+    // Schedule the work through the message loop to 1) prevent infinite
+    // recursion and 2) avoid blocking the thread for too long.
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::Bind(&QuicPacketReader::OnReadComplete,
+                              weak_factory_.GetWeakPtr(), rv));
+  } else {
+    OnReadComplete(rv);
+  }
+}
+
+void QuicPacketReader::OnReadComplete(int result) {
+  read_pending_ = false;
+  if (result == 0)
+    result = ERR_CONNECTION_CLOSED;
+
+  if (result < 0) {
+    visitor_->OnReadError(result);
+    return;
+  }
+
+  QuicEncryptedPacket packet(read_buffer_->data(), result);
+  IPEndPoint local_address;
+  IPEndPoint peer_address;
+  socket_->GetLocalAddress(&local_address);
+  socket_->GetPeerAddress(&peer_address);
+  if (!visitor_->OnPacket(packet, local_address, peer_address))
+    return;
+
+  StartReading();
+}
+
+}  // namespace net