Refactoring DataChannelController from PeerConnection part 4

This CL:
- Moved HasDataChannel and data_channel_type_
- Moved rtp_data_channels_
- Moved sctp_data_channels_
- Moved data_channel_controller to its own .h file
- Various changes to reduce the coupling between the classes
- Removed friendship between DataChannelController and PeerConnection

Bug: webrtc:11146
Change-Id: Ib8c395e4c90ce34baf40812d1dade0ffa79f2438
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/161094
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29987}
diff --git a/pc/data_channel_controller.h b/pc/data_channel_controller.h
new file mode 100644
index 0000000..bfce16c
--- /dev/null
+++ b/pc/data_channel_controller.h
@@ -0,0 +1,214 @@
+/*
+ *  Copyright 2019 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef PC_DATA_CHANNEL_CONTROLLER_H_
+#define PC_DATA_CHANNEL_CONTROLLER_H_
+
+#include <map>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "pc/channel.h"
+#include "pc/data_channel.h"
+
+namespace webrtc {
+
+class PeerConnection;
+
+class DataChannelController : public DataChannelProviderInterface,
+                              public DataChannelSink {
+ public:
+  explicit DataChannelController(PeerConnection* pc) : pc_(pc) {}
+
+  // Implements DataChannelProviderInterface.
+  bool SendData(const cricket::SendDataParams& params,
+                const rtc::CopyOnWriteBuffer& payload,
+                cricket::SendDataResult* result) override;
+  bool ConnectDataChannel(DataChannel* webrtc_data_channel) override;
+  void DisconnectDataChannel(DataChannel* webrtc_data_channel) override;
+  void AddSctpDataStream(int sid) override;
+  void RemoveSctpDataStream(int sid) override;
+  bool ReadyToSendData() const override;
+
+  // Implements DataChannelSink.
+  void OnDataReceived(int channel_id,
+                      DataMessageType type,
+                      const rtc::CopyOnWriteBuffer& buffer) override;
+  void OnChannelClosing(int channel_id) override;
+  void OnChannelClosed(int channel_id) override;
+  void OnReadyToSend() override;
+
+  // Called from PeerConnection::SetupDataChannelTransport_n
+  void SetupDataChannelTransport_n();
+  // Called from PeerConnection::TeardownDataChannelTransport_n
+  void TeardownDataChannelTransport_n();
+
+  // Called from PeerConnection::OnTransportChanged
+  // to make required changes to datachannels' transports.
+  void OnTransportChanged(
+      DataChannelTransportInterface* data_channel_transport);
+
+  // Creates channel and adds it to the collection of DataChannels that will
+  // be offered in a SessionDescription.
+  rtc::scoped_refptr<DataChannel> InternalCreateDataChannel(
+      const std::string& label,
+      const InternalDataChannelInit*
+          config) /* RTC_RUN_ON(signaling_thread()) */;
+  void AllocateSctpSids(rtc::SSLRole role);
+
+  DataChannel* FindDataChannelBySid(int sid) const;
+
+  // Checks if any data channel has been added.
+  bool HasDataChannels() const;
+  bool HasSctpDataChannels() const {
+    RTC_DCHECK_RUN_ON(signaling_thread());
+    return !sctp_data_channels_.empty();
+  }
+  bool HasRtpDataChannels() const {
+    RTC_DCHECK_RUN_ON(signaling_thread());
+    return !rtp_data_channels_.empty();
+  }
+
+  // Called when it's appropriate to delete released datachannels.
+  void FreeDataChannels() {
+    RTC_DCHECK_RUN_ON(signaling_thread());
+    sctp_data_channels_to_free_.clear();
+  }
+
+  void UpdateLocalRtpDataChannels(const cricket::StreamParamsVec& streams);
+  void UpdateRemoteRtpDataChannels(const cricket::StreamParamsVec& streams);
+
+  // Accessors
+  cricket::DataChannelType data_channel_type() const {
+    return data_channel_type_;
+  }
+  void set_data_channel_type(cricket::DataChannelType type) {
+    data_channel_type_ = type;
+  }
+  cricket::RtpDataChannel* rtp_data_channel() const {
+    return rtp_data_channel_;
+  }
+  void set_rtp_data_channel(cricket::RtpDataChannel* channel) {
+    rtp_data_channel_ = channel;
+  }
+  DataChannelTransportInterface* data_channel_transport() const {
+    return data_channel_transport_;
+  }
+  void set_data_channel_transport(DataChannelTransportInterface* transport) {
+    data_channel_transport_ = transport;
+  }
+  const std::map<std::string, rtc::scoped_refptr<DataChannel>>*
+  rtp_data_channels() const {
+    RTC_DCHECK_RUN_ON(signaling_thread());
+    return &rtp_data_channels_;
+  }
+  const std::vector<rtc::scoped_refptr<DataChannel>>* sctp_data_channels()
+      const {
+    RTC_DCHECK_RUN_ON(signaling_thread());
+    return &sctp_data_channels_;
+  }
+
+  sigslot::signal1<DataChannel*>& SignalDataChannelCreated() {
+    RTC_DCHECK_RUN_ON(signaling_thread());
+    return SignalDataChannelCreated_;
+  }
+  // Called when the transport for the data channels is closed or destroyed.
+  void OnTransportChannelClosed();
+
+  void OnSctpDataChannelClosed(DataChannel* channel);
+
+ private:
+  // Parses and handles open messages.  Returns true if the message is an open
+  // message, false otherwise.
+  bool HandleOpenMessage_s(const cricket::ReceiveDataParams& params,
+                           const rtc::CopyOnWriteBuffer& buffer)
+      RTC_RUN_ON(signaling_thread());
+  // Called when a valid data channel OPEN message is received.
+  void OnDataChannelOpenMessage(const std::string& label,
+                                const InternalDataChannelInit& config)
+      RTC_RUN_ON(signaling_thread());
+
+  void CreateRemoteRtpDataChannel(const std::string& label,
+                                  uint32_t remote_ssrc)
+      RTC_RUN_ON(signaling_thread());
+
+  void UpdateClosingRtpDataChannels(
+      const std::vector<std::string>& active_channels,
+      bool is_local_update) RTC_RUN_ON(signaling_thread());
+
+  rtc::Thread* network_thread() const;
+  rtc::Thread* signaling_thread() const;
+
+  // Specifies which kind of data channel is allowed. This is controlled
+  // by the chrome command-line flag and constraints:
+  // 1. If chrome command-line switch 'enable-sctp-data-channels' is enabled,
+  // constraint kEnableDtlsSrtp is true, and constaint kEnableRtpDataChannels is
+  // not set or false, SCTP is allowed (DCT_SCTP);
+  // 2. If constraint kEnableRtpDataChannels is true, RTP is allowed (DCT_RTP);
+  // 3. If both 1&2 are false, data channel is not allowed (DCT_NONE).
+  cricket::DataChannelType data_channel_type_ =
+      cricket::DCT_NONE;  // TODO(bugs.webrtc.org/9987): Accessed on both
+                          // signaling and network thread.
+
+  // Plugin transport used for data channels.  Pointer may be accessed and
+  // checked from any thread, but the object may only be touched on the
+  // network thread.
+  // TODO(bugs.webrtc.org/9987): Accessed on both signaling and network
+  // thread.
+  DataChannelTransportInterface* data_channel_transport_ = nullptr;
+
+  // Cached value of whether the data channel transport is ready to send.
+  bool data_channel_transport_ready_to_send_
+      RTC_GUARDED_BY(signaling_thread()) = false;
+
+  // |rtp_data_channel_| is used if in RTP data channel mode,
+  // |data_channel_transport_| when using SCTP.
+  cricket::RtpDataChannel* rtp_data_channel_ = nullptr;
+  // TODO(bugs.webrtc.org/9987): Accessed on both
+  // signaling and some other thread.
+
+  SctpSidAllocator sid_allocator_ /* RTC_GUARDED_BY(signaling_thread()) */;
+  std::vector<rtc::scoped_refptr<DataChannel>> sctp_data_channels_
+      RTC_GUARDED_BY(signaling_thread());
+  std::vector<rtc::scoped_refptr<DataChannel>> sctp_data_channels_to_free_
+      RTC_GUARDED_BY(signaling_thread());
+
+  // Map of label -> DataChannel
+  std::map<std::string, rtc::scoped_refptr<DataChannel>> rtp_data_channels_
+      RTC_GUARDED_BY(signaling_thread());
+
+  // Signals from |data_channel_transport_|.  These are invoked on the
+  // signaling thread.
+  sigslot::signal1<bool> SignalDataChannelTransportWritable_s
+      RTC_GUARDED_BY(signaling_thread());
+  sigslot::signal2<const cricket::ReceiveDataParams&,
+                   const rtc::CopyOnWriteBuffer&>
+      SignalDataChannelTransportReceivedData_s
+          RTC_GUARDED_BY(signaling_thread());
+  sigslot::signal1<int> SignalDataChannelTransportChannelClosing_s
+      RTC_GUARDED_BY(signaling_thread());
+  sigslot::signal1<int> SignalDataChannelTransportChannelClosed_s
+      RTC_GUARDED_BY(signaling_thread());
+
+  sigslot::signal1<DataChannel*> SignalDataChannelCreated_
+      RTC_GUARDED_BY(signaling_thread());
+
+  // Used to invoke data channel transport signals on the signaling thread.
+  std::unique_ptr<rtc::AsyncInvoker> data_channel_transport_invoker_
+      RTC_GUARDED_BY(network_thread());
+
+  // Owning PeerConnection.
+  PeerConnection* const pc_;
+};
+
+}  // namespace webrtc
+
+#endif  // PC_DATA_CHANNEL_CONTROLLER_H_