Implement ChannelMultiplexer.

remoting/protocol/channel_multiplexer.cc

+// Copyright (c) 2012 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 "remoting/protocol/channel_multiplexer.h"
+
+#include <string.h>
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/location.h"
+#include "base/stl_util.h"
+#include "net/base/net_errors.h"
+#include "net/socket/stream_socket.h"
+#include "remoting/protocol/util.h"
+
+namespace remoting {
+namespace protocol {
+
+namespace {
+const int kChannelIdUnknown = -1;
+const int kMaxPacketSize = 1024;
+
+class PendingPacket {
+ public:
+  PendingPacket(scoped_ptr<MultiplexPacket> packet,
+                const base::Closure& done_task)
+      : packet(packet.Pass()),
+        done_task(done_task),
+        pos(0U) {
+  }
+  ~PendingPacket() {
+    done_task.Run();
+  }
+
+  bool is_empty() { return pos >= packet->data().size(); }
+
+  int Read(char* buffer, size_t size) {
+    size = std::min(size, packet->data().size() - pos);
+    memcpy(buffer, packet->data().data() + pos, size);
+    pos += size;
+    return size;
+  }
+
+ private:
+  scoped_ptr<MultiplexPacket> packet;
+  base::Closure done_task;
+  size_t pos;
+
+  DISALLOW_COPY_AND_ASSIGN(PendingPacket);
+};
+
+}  // namespace
+
+const char ChannelMultiplexer::kMuxChannelName[] = "mux";
+
+struct ChannelMultiplexer::PendingChannel {
+  PendingChannel(const std::string& name,
+                 const StreamChannelCallback& callback)
+      : name(name), callback(callback) {
+  }
+  std::string name;
+  StreamChannelCallback callback;
+};
+
+class ChannelMultiplexer::MuxChannel {
+ public:
+  MuxChannel(ChannelMultiplexer* multiplexer, const std::string& name,
+             int send_id);
+  ~MuxChannel();
+
+  const std::string& name() { return name_; }
+  int receive_id() { return receive_id_; }
+  void set_receive_id(int id) { receive_id_ = id; }
+
+  // Called by ChannelMultiplexer.
+  scoped_ptr<net::StreamSocket> CreateSocket();
+  void OnIncomingPacket(scoped_ptr<MultiplexPacket> packet,
+                        const base::Closure& done_task);
+  void OnWriteFailed();
+
+  // Called by MuxSocket.
+  void OnSocketDestroyed();
+  bool DoWrite(scoped_ptr<MultiplexPacket> packet,
+               const base::Closure& done_task);
+  int DoRead(net::IOBuffer* buffer, int buffer_len);
+
+ private:
+  ChannelMultiplexer* multiplexer_;
+  std::string name_;
+  int send_id_;
+  bool id_sent_;
+  int receive_id_;
+  MuxSocket* socket_;
+  std::list<PendingPacket*> pending_packets_;
+
+  DISALLOW_COPY_AND_ASSIGN(MuxChannel);
+};
+
+class ChannelMultiplexer::MuxSocket : public net::StreamSocket,
+                                      public base::NonThreadSafe,
+                                      public base::SupportsWeakPtr<MuxSocket> {
+ public:
+  MuxSocket(MuxChannel* channel);
+  ~MuxSocket();
+
+  void OnWriteComplete();
+  void OnWriteFailed();
+  void OnPacketReceived();
+
+  // net::StreamSocket interface.
+  virtual int Read(net::IOBuffer* buffer, int buffer_len,
+                   const net::CompletionCallback& callback) OVERRIDE;
+  virtual int Write(net::IOBuffer* buffer, int buffer_len,
+                    const net::CompletionCallback& callback) OVERRIDE;
+
+  virtual bool SetReceiveBufferSize(int32 size) OVERRIDE {
+    NOTIMPLEMENTED();
+    return false;
+  }
+  virtual bool SetSendBufferSize(int32 size) OVERRIDE {
+    NOTIMPLEMENTED();
+    return false;
+  }
+
+  virtual int Connect(const net::CompletionCallback& callback) OVERRIDE {
+    NOTIMPLEMENTED();
+    return net::ERR_FAILED;
+  }
+  virtual void Disconnect() OVERRIDE {
+    NOTIMPLEMENTED();
+  }
+  virtual bool IsConnected() const OVERRIDE {
+    NOTIMPLEMENTED();
+    return true;
+  }
+  virtual bool IsConnectedAndIdle() const OVERRIDE {
+    NOTIMPLEMENTED();
+    return false;
+  }
+  virtual int GetPeerAddress(net::IPEndPoint* address) const OVERRIDE {
+    NOTIMPLEMENTED();
+    return net::ERR_FAILED;
+  }
+  virtual int GetLocalAddress(net::IPEndPoint* address) const OVERRIDE {
+    NOTIMPLEMENTED();
+    return net::ERR_FAILED;
+  }
+  virtual const net::BoundNetLog& NetLog() const OVERRIDE {
+    NOTIMPLEMENTED();
+    return net_log_;
+  }
+  virtual void SetSubresourceSpeculation() OVERRIDE {
+    NOTIMPLEMENTED();
+  }
+  virtual void SetOmniboxSpeculation() OVERRIDE {
+    NOTIMPLEMENTED();
+  }
+  virtual bool WasEverUsed() const OVERRIDE {
+    return true;
+  }
+  virtual bool UsingTCPFastOpen() const OVERRIDE {
+    return false;
+  }
+  virtual int64 NumBytesRead() const OVERRIDE {
+    NOTIMPLEMENTED();
+    return 0;
+  }
+  virtual base::TimeDelta GetConnectTimeMicros() const OVERRIDE {
+    NOTIMPLEMENTED();
+    return base::TimeDelta();
+  }
+  virtual bool WasNpnNegotiated() const OVERRIDE {
+    return false;
+  }
+  virtual net::NextProto GetNegotiatedProtocol() const OVERRIDE {
+    return net::kProtoUnknown;
+  }
+  virtual bool GetSSLInfo(net::SSLInfo* ssl_info) OVERRIDE {
+    NOTIMPLEMENTED();
+    return false;
+  }
+
+ private:
+  MuxChannel* channel_;
+
+  net::CompletionCallback read_callback_;
+  scoped_refptr<net::IOBuffer> read_buffer_;
+  int read_buffer_size_;
+
+  bool write_pending_;
+  int write_result_;
+  net::CompletionCallback write_callback_;
+
+  net::BoundNetLog net_log_;
+
+  DISALLOW_COPY_AND_ASSIGN(MuxSocket);
+};
+
+
+ChannelMultiplexer::MuxChannel::MuxChannel(
+    ChannelMultiplexer* multiplexer,
+    const std::string& name,
+    int send_id)
+    : multiplexer_(multiplexer),
+      name_(name),
+      send_id_(send_id),
+      id_sent_(false),
+      receive_id_(kChannelIdUnknown),
+      socket_(NULL) {
+}
+
+ChannelMultiplexer::MuxChannel::~MuxChannel() {
+  // Socket must be destroyed before the channel.
+  DCHECK(!socket_);
+  STLDeleteElements(&pending_packets_);
+}
+
+scoped_ptr<net::StreamSocket> ChannelMultiplexer::MuxChannel::CreateSocket() {
+  DCHECK(!socket_);  // Can't create more than one socket per channel.
+  scoped_ptr<MuxSocket> result(new MuxSocket(this));
+  socket_ = result.get();
+  return result.PassAs<net::StreamSocket>();
+}
+
+void ChannelMultiplexer::MuxChannel::OnIncomingPacket(
+    scoped_ptr<MultiplexPacket> packet,
+    const base::Closure& done_task) {
+  DCHECK_EQ(packet->channel_id(), receive_id_);
+  if (packet->data().size() > 0) {
+    pending_packets_.push_back(new PendingPacket(packet.Pass(), done_task));
+    if (socket_) {
+      // Notify the socket that we have more data.
+      socket_->OnPacketReceived();
+    }
+  }
+}
+
+void ChannelMultiplexer::MuxChannel::OnWriteFailed() {
+  if (socket_)
+    socket_->OnWriteFailed();
+}
+
+void ChannelMultiplexer::MuxChannel::OnSocketDestroyed() {
+  DCHECK(socket_);
+  socket_ = NULL;
+}
+
+bool ChannelMultiplexer::MuxChannel::DoWrite(
+    scoped_ptr<MultiplexPacket> packet,
+    const base::Closure& done_task) {
+  packet->set_channel_id(send_id_);
+  if (!id_sent_) {
+    packet->set_channel_name(name_);
+    id_sent_ = true;
+  }
+  return multiplexer_->DoWrite(packet.Pass(), done_task);
+}
+
+int ChannelMultiplexer::MuxChannel::DoRead(net::IOBuffer* buffer,
+                                           int buffer_len) {
+  int pos = 0;
+  while (buffer_len > 0 && !pending_packets_.empty()) {
+    DCHECK(!pending_packets_.front()->is_empty());
+    int result = pending_packets_.front()->Read(
+        buffer->data() + pos, buffer_len);
+    DCHECK_LE(result, buffer_len);
+    pos += result;
+    buffer_len -= pos;
+    if (pending_packets_.front()->is_empty()) {
+      delete pending_packets_.front();
+      pending_packets_.erase(pending_packets_.begin());
+    }
+  }
+  return pos;
+}
+
+ChannelMultiplexer::MuxSocket::MuxSocket(MuxChannel* channel)
+    : channel_(channel),
+      read_buffer_size_(0),
+      write_pending_(false),
+      write_result_(0) {
+}
+
+ChannelMultiplexer::MuxSocket::~MuxSocket() {
+  channel_->OnSocketDestroyed();
+}
+
+int ChannelMultiplexer::MuxSocket::Read(
+    net::IOBuffer* buffer, int buffer_len,
+    const net::CompletionCallback& callback) {
+  DCHECK(CalledOnValidThread());
+  DCHECK(read_callback_.is_null());
+
+  int result = channel_->DoRead(buffer, buffer_len);
+  if (result == 0) {
+    read_buffer_ = buffer;
+    read_buffer_size_ = buffer_len;
+    read_callback_ = callback;
+    return net::ERR_IO_PENDING;
+  }
+  return result;
+}
+
+int ChannelMultiplexer::MuxSocket::Write(
+    net::IOBuffer* buffer, int buffer_len,
+    const net::CompletionCallback& callback) {
+  DCHECK(CalledOnValidThread());
+
+  scoped_ptr<MultiplexPacket> packet(new MultiplexPacket());
+  size_t size = std::min(kMaxPacketSize, buffer_len);
+  packet->mutable_data()->assign(buffer->data(), size);
+
+  write_pending_ = true;
+  bool result = channel_->DoWrite(packet.Pass(), base::Bind(
+      &ChannelMultiplexer::MuxSocket::OnWriteComplete, AsWeakPtr()));
+
+  if (!result) {
+    // Cannot complete the write, e.g. if the connection has been terminated.
+    return net::ERR_FAILED;
+  }
+
+  // OnWriteComplete() might be called above synchronously.
+  if (write_pending_) {
+    DCHECK(write_callback_.is_null());
+    write_callback_ = callback;
+    write_result_ = size;
+    return net::ERR_IO_PENDING;
+  }
+
+  return size;
+}
+
+void ChannelMultiplexer::MuxSocket::OnWriteComplete() {
+  write_pending_ = false;
+  if (!write_callback_.is_null()) {
+    net::CompletionCallback cb;
+    std::swap(cb, write_callback_);
+    cb.Run(write_result_);
+  }
+}
+
+void ChannelMultiplexer::MuxSocket::OnWriteFailed() {
+  if (!write_callback_.is_null()) {
+    net::CompletionCallback cb;
+    std::swap(cb, write_callback_);
+    cb.Run(net::ERR_FAILED);
+  }
+}
+
+void ChannelMultiplexer::MuxSocket::OnPacketReceived() {
+  if (!read_callback_.is_null()) {
+    int result = channel_->DoRead(read_buffer_, read_buffer_size_);
+    read_buffer_ = NULL;
+    DCHECK_GT(result, 0);
+    net::CompletionCallback cb;
+    std::swap(cb, read_callback_);
+    cb.Run(result);
+  }
+}
+
+ChannelMultiplexer::ChannelMultiplexer(ChannelFactory* factory,
+                                       const std::string& base_channel_name)
+    : base_channel_factory_(factory),
+      base_channel_name_(base_channel_name),
+      next_channel_id_(0),
+      destroyed_flag_(NULL) {
+  factory->CreateStreamChannel(
+      base_channel_name,
+      base::Bind(&ChannelMultiplexer::OnBaseChannelReady,
+                 base::Unretained(this)));
+}
+
+ChannelMultiplexer::~ChannelMultiplexer() {
+  DCHECK(pending_channels_.empty());
+  STLDeleteValues(&channels_);
+
+  // Cancel creation of the base channel if it hasn't finished.
+  if (base_channel_factory_)
+    base_channel_factory_->CancelChannelCreation(base_channel_name_);
+
+  if (destroyed_flag_)
+    *destroyed_flag_ = true;
+}
+
+void ChannelMultiplexer::CreateStreamChannel(
+    const std::string& name,
+    const StreamChannelCallback& callback) {
+  if (base_channel_.get()) {
+    // Already have |base_channel_|. Create new multiplexed channel
+    // synchronously.
+    callback.Run(GetOrCreateChannel(name)->CreateSocket());
+  } else if (!base_channel_.get() && !base_channel_factory_) {
+    // Fail synchronously if we failed to create |base_channel_|.
+    callback.Run(scoped_ptr<net::StreamSocket>());
+  } else {
+    // Still waiting for the |base_channel_|.
+    pending_channels_.push_back(PendingChannel(name, callback));
+  }
+}
+
+void ChannelMultiplexer::CreateDatagramChannel(
+    const std::string& name,
+    const DatagramChannelCallback& callback) {
+  NOTIMPLEMENTED();
+  callback.Run(scoped_ptr<net::Socket>());
+}
+
+void ChannelMultiplexer::CancelChannelCreation(const std::string& name) {
+  for (std::list<PendingChannel>::iterator it = pending_channels_.begin();
+       it != pending_channels_.end(); ++it) {
+    if (it->name == name) {
+      pending_channels_.erase(it);
+      return;
+    }
+  }
+  NOTREACHED();

[Wez, 2012/08/07 21:44:45]

Do you really want a NOTREACHED() here; it seems valid for a caller to play it
safe by calling CancelChannelCreation() for all channels they might ever have
tried to create, without caring whether they already succeeded.

[Sergey Ulanov, 2012/08/07 22:25:14]

Yes, you are right.

+}
+
+void ChannelMultiplexer::OnBaseChannelReady(
+    scoped_ptr<net::StreamSocket> socket) {
+  base_channel_factory_ = NULL;
+  base_channel_ = socket.Pass();
+
+  if (!base_channel_.get()) {
+    // Notify all callers that we can't create any channels.
+    for (std::list<PendingChannel>::iterator it = pending_channels_.begin();
+         it != pending_channels_.end(); ++it) {
+      it->callback.Run(scoped_ptr<net::StreamSocket>());
+    }
+    pending_channels_.clear();
+    return;
+  }
+
+  // Initialize reader and writer.
+  reader_.Init(base_channel_.get(),
+               base::Bind(&ChannelMultiplexer::OnIncomingPacket,
+                          base::Unretained(this)));
+  writer_.Init(base_channel_.get(),
+               base::Bind(&ChannelMultiplexer::OnWriteFailed,
+                          base::Unretained(this)));
+
+  // Now create all pending channels.
+  for (std::list<PendingChannel>::iterator it = pending_channels_.begin();
+       it != pending_channels_.end(); ++it) {
+    it->callback.Run(GetOrCreateChannel(it->name)->CreateSocket());
+  }
+  pending_channels_.clear();
+}
+
+ChannelMultiplexer::MuxChannel* ChannelMultiplexer::GetOrCreateChannel(
+    const std::string& name) {
+  // Check if we already have a channel with the requested name.
+  std::map<std::string, MuxChannel*>::iterator it = channels_.find(name);
+  if (it != channels_.end())
+    return it->second;
+
+  // Create a new channel if we haven't found existing one.
+  MuxChannel* channel = new MuxChannel(this, name, next_channel_id_);
+  ++next_channel_id_;
+  channels_[channel->name()] = channel;
+  return channel;
+}
+
+
+void ChannelMultiplexer::OnWriteFailed(int error) {
+  bool destroyed = false;
+  destroyed_flag_ = &destroyed;
+  for (std::map<std::string, MuxChannel*>::iterator it = channels_.begin();
+       it != channels_.end(); ++it) {
+    it->second->OnWriteFailed();
+    if (destroyed)
+      return;
+  }
+  destroyed_flag_ = NULL;
+}
+
+void ChannelMultiplexer::OnIncomingPacket(scoped_ptr<MultiplexPacket> packet,
+                                          const base::Closure& done_task) {
+  if (!packet->has_channel_id()) {
+    LOG(ERROR) << "Received packet without channel_id.";
+    done_task.Run();
+    return;
+  }
+
+  int receive_id = packet->channel_id();
+  MuxChannel* channel = NULL;
+  std::map<int, MuxChannel*>::iterator it =
+      channels_by_receive_id_.find(receive_id);
+  if (it != channels_by_receive_id_.end()) {
+    channel = it->second;
+  } else {
+    // This is a new |channel_id| we haven't seen before. Look it up by name.
+    if (!packet->has_channel_name()) {
+      LOG(ERROR) << "Received packet with unknown channel_id and "
+          "without channel_name.";
+      done_task.Run();
+      return;
+    }
+    channel = GetOrCreateChannel(packet->channel_name());
+    channel->set_receive_id(receive_id);
+    channels_by_receive_id_[receive_id] = channel;
+  }
+
+  channel->OnIncomingPacket(packet.Pass(), done_task);
+}
+
+bool ChannelMultiplexer::DoWrite(scoped_ptr<MultiplexPacket> packet,
+                                 const base::Closure& done_task) {
+  return writer_.Write(SerializeAndFrameMessage(*packet), done_task);
+}
+
+}  // namespace protocol
+}  // namespace remoting