TransportController refactoring

webrtc/p2p/base/transport.h

 /*
  *  Copyright 2004 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.
  */
 
 // A Transport manages a set of named channels of the same type.
 //
 // Subclasses choose the appropriate class to instantiate for each channel;
 // however, this base class keeps track of the channels by name, watches their
 // state changes (in order to update the manager's state), and forwards
 // requests to begin connecting or to reset to each of the channels.
 //
-// On Threading:  Transport performs work on both the signaling and worker
-// threads.  For subclasses, the rule is that all signaling related calls will
-// be made on the signaling thread and all channel related calls (including
-// signaling for a channel) will be made on the worker thread.  When
-// information needs to be sent between the two threads, this class should do
-// the work (e.g., OnRemoteCandidate).
-//
-// Note: Subclasses must call DestroyChannels() in their own constructors.
-// It is not possible to do so here because the subclass constructor will
+// Note: Subclasses must call DestroyChannels() in their own destructors.
+// It is not possible to do so here because the subclass destructor will
 // already have run.
 
 #ifndef WEBRTC_P2P_BASE_TRANSPORT_H_
 #define WEBRTC_P2P_BASE_TRANSPORT_H_
 
 #include <map>
 #include <string>
 #include <vector>
 #include "webrtc/p2p/base/candidate.h"
 #include "webrtc/p2p/base/constants.h"
 #include "webrtc/p2p/base/sessiondescription.h"
 #include "webrtc/p2p/base/transportinfo.h"
-#include "webrtc/base/criticalsection.h"
 #include "webrtc/base/messagequeue.h"
 #include "webrtc/base/sigslot.h"
 #include "webrtc/base/sslstreamadapter.h"
 
-namespace rtc {
-class Thread;
-}
-
 namespace cricket {
 
 class PortAllocator;
 class TransportChannel;
 class TransportChannelImpl;
 
 typedef std::vector<Candidate> Candidates;
 
 // For "writable", "readable", and "receiving", we need to differentiate between
 // none, all, and some.
@@ skipping 70 matching lines @@
   TransportChannelStatsList channel_stats;
 };
 
 bool BadTransportDescription(const std::string& desc, std::string* err_desc);
 
 bool IceCredentialsChanged(const std::string& old_ufrag,
                            const std::string& old_pwd,
                            const std::string& new_ufrag,
                            const std::string& new_pwd);
 
-class Transport : public rtc::MessageHandler,
-                  public sigslot::has_slots<> {
+class Transport : public sigslot::has_slots<> {
  public:
-  Transport(rtc::Thread* signaling_thread,
-            rtc::Thread* worker_thread,
-            const std::string& content_name,
+  enum CandidateGatheringState {
+    kGatheringNew = 0,
+    kGatheringGathering,
+    kGatheringDone,

[pthatcher1, 2015/08/10 20:40:17]

Done => Complete

Also, this enum should probably live outside the scope of Transport.  Just call
it cricket::IceGatheringState.

[Taylor Brandstetter, 2015/08/11 01:20:08]

Done.

+  };
+
+  Transport(const std::string& content_name,
             const std::string& type,
             PortAllocator* allocator);
   virtual ~Transport();
 
-  // Returns the signaling thread. The app talks to Transport on this thread.
-  rtc::Thread* signaling_thread() { return signaling_thread_; }
-  // Returns the worker thread. The actual networking is done on this thread.
-  rtc::Thread* worker_thread() { return worker_thread_; }
-
   // Returns the content_name of this transport.
   const std::string& content_name() const { return content_name_; }
   // Returns the type of this transport.
   const std::string& type() const { return type_; }
 
   // Returns the port allocator object for this transport.
   PortAllocator* port_allocator() { return allocator_; }
 
   // Returns the readable and states of this manager.  These bits are the ORs
   // of the corresponding bits on the managed channels.  Each time one of these
@@ skipping 14 matching lines @@
   bool all_channels_readable() const {
     return (readable_ == TRANSPORT_STATE_ALL);
   }
   bool all_channels_writable() const {
     return (writable_ == TRANSPORT_STATE_ALL);
   }
   bool any_channel_receiving() const {
     return (receiving_ == TRANSPORT_STATE_SOME ||
             receiving_ == TRANSPORT_STATE_ALL);
   }
+  bool local_description_set() const {
+    return local_description_set_;
+  }
+  bool remote_description_set() const {
+    return remote_description_set_;
+  }
+
+  // Checks if all channels are completed
+  bool Completed() const;
+
+  CandidateGatheringState candidate_gathering_state() const {
+    return candidate_gathering_state_;
+  }
 
   sigslot::signal1<Transport*> SignalReadableState;
   sigslot::signal1<Transport*> SignalWritableState;
   sigslot::signal1<Transport*> SignalReceivingState;
   sigslot::signal1<Transport*> SignalCompleted;
   sigslot::signal1<Transport*> SignalFailed;
 
   // Returns whether the client has requested the channels to connect.
   bool connect_requested() const { return connect_requested_; }
 
   void SetIceRole(IceRole role);
   IceRole ice_role() const { return ice_role_; }
 
   void SetIceTiebreaker(uint64 IceTiebreaker) { tiebreaker_ = IceTiebreaker; }
   uint64 IceTiebreaker() { return tiebreaker_; }
 
   void SetChannelReceivingTimeout(int timeout_ms);
 
   // Must be called before applying local session description.
-  void SetIdentity(rtc::SSLIdentity* identity);
+  virtual void SetIdentity(rtc::SSLIdentity* identity) {}
 
   // Get a copy of the local identity provided by SetIdentity.
-  bool GetIdentity(rtc::SSLIdentity** identity);
+  virtual bool GetIdentity(rtc::SSLIdentity** identity) { return false; }
 
   // Get a copy of the remote certificate in use by the specified channel.
   bool GetRemoteCertificate(rtc::SSLCertificate** cert);
 
   TransportProtocol protocol() const { return protocol_; }
 
   // Create, destroy, and lookup the channels of this type by their components.
   TransportChannelImpl* CreateChannel(int component);
-  // Note: GetChannel may lead to race conditions, since the mutex is not held
-  // after the pointer is returned.
+
   TransportChannelImpl* GetChannel(int component);
-  // Note: HasChannel does not lead to race conditions, unlike GetChannel.
+
   bool HasChannel(int component) {
     return (NULL != GetChannel(component));
   }
   bool HasChannels();
   void DestroyChannel(int component);
 
   // Set the local TransportDescription to be used by TransportChannels.
   // This should be called before ConnectChannels().
   bool SetLocalTransportDescription(const TransportDescription& description,
                                     ContentAction action,
@@ skipping 11 matching lines @@
 
   // Resets all of the channels back to their initial state.  They are no
   // longer connecting.
   void ResetChannels();
 
   // Destroys every channel created so far.
   void DestroyAllChannels();
 
   bool GetStats(TransportStats* stats);
 
-  // Before any stanza is sent, the manager will request signaling.  Once
-  // signaling is available, the client should call OnSignalingReady.  Once
-  // this occurs, the transport (or its channels) can send any waiting stanzas.
-  // OnSignalingReady invokes OnTransportSignalingReady and then forwards this
-  // signal to each channel.
-  sigslot::signal1<Transport*> SignalRequestSignaling;
-  void OnSignalingReady();
+  sigslot::signal1<Transport*> SignalCandidatesAllocationStarted;
 
   // Handles sending of ready candidates and receiving of remote candidates.
   sigslot::signal2<Transport*,
                    const std::vector<Candidate>&> SignalCandidatesReady;
+  sigslot::signal1<Transport*> SignalCandidatesAllocationDone;
 
-  sigslot::signal1<Transport*> SignalCandidatesAllocationDone;
-  void OnRemoteCandidates(const std::vector<Candidate>& candidates);
+  // Called when one or more candidates are ready from the remote peer.
+  bool AddRemoteCandidates(
+      const std::vector<Candidate>& candidates, std::string* error);
+
+  void AddRemoteCandidate(const Candidate& candidate);

[pthatcher1, 2015/08/10 20:40:17]

Why do we need both of these?

[Taylor Brandstetter, 2015/08/11 01:20:08]

I'm not sure; this was left over from your original CL. I'll remove it, it
appears unnecessary.

 
   // If candidate is not acceptable, returns false and sets error.
   // Call this before calling OnRemoteCandidates.
   virtual bool VerifyCandidate(const Candidate& candidate,
                                std::string* error);
 
   // Signals when the best connection for a channel changes.
   sigslot::signal3<Transport*,
                    int,  // component
                    const Candidate&> SignalRouteChange;
 
   // Forwards the signal from TransportChannel to BaseSession.
   sigslot::signal0<> SignalRoleConflict;
 
-  virtual bool GetSslRole(rtc::SSLRole* ssl_role) const;
+  virtual bool GetSslRole(rtc::SSLRole* ssl_role) const { return false; }
 
   // Must be called before channel is starting to connect.
-  virtual bool SetSslMaxProtocolVersion(rtc::SSLProtocolVersion version);
+  virtual bool SetSslMaxProtocolVersion(rtc::SSLProtocolVersion version) {
+    return false;
+  }
 
  protected:
   // These are called by Create/DestroyChannel above in order to create or
   // destroy the appropriate type of channel.
   virtual TransportChannelImpl* CreateTransportChannel(int component) = 0;
   virtual void DestroyTransportChannel(TransportChannelImpl* channel) = 0;
 
-  // Informs the subclass that we received the signaling ready message.
-  virtual void OnTransportSignalingReady() {}
-
   // The current local transport description, for use by derived classes
   // when performing transport description negotiation.
   const TransportDescription* local_description() const {
     return local_description_.get();
   }
 
   // The current remote transport description, for use by derived classes
   // when performing transport description negotiation.
   const TransportDescription* remote_description() const {
     return remote_description_.get();
   }
 
-  virtual void SetIdentity_w(rtc::SSLIdentity* identity) {}
-
-  virtual bool GetIdentity_w(rtc::SSLIdentity** identity) {
-    return false;
-  }
-
   // Pushes down the transport parameters from the local description, such
   // as the ICE ufrag and pwd.
   // Derived classes can override, but must call the base as well.
-  virtual bool ApplyLocalTransportDescription_w(TransportChannelImpl* channel,
+  virtual bool ApplyLocalTransportDescription(TransportChannelImpl* channel,
                                                 std::string* error_desc);
 
   // Pushes down remote ice credentials from the remote description to the
   // transport channel.
-  virtual bool ApplyRemoteTransportDescription_w(TransportChannelImpl* ch,
+  virtual bool ApplyRemoteTransportDescription(TransportChannelImpl* ch,
                                                  std::string* error_desc);
 
   // Negotiates the transport parameters based on the current local and remote
   // transport description, such at the version of ICE to use, and whether DTLS
   // should be activated.
   // Derived classes can negotiate their specific parameters here, but must call
   // the base as well.
-  virtual bool NegotiateTransportDescription_w(ContentAction local_role,
+  virtual bool NegotiateTransportDescription(ContentAction local_role,
                                                std::string* error_desc);
 
   // Pushes down the transport parameters obtained via negotiation.
   // Derived classes can set their specific parameters here, but must call the
   // base as well.
-  virtual bool ApplyNegotiatedTransportDescription_w(
+  virtual bool ApplyNegotiatedTransportDescription(
       TransportChannelImpl* channel, std::string* error_desc);
 
-  virtual bool GetSslRole_w(rtc::SSLRole* ssl_role) const {
-    return false;
-  }
-
-  virtual bool SetSslMaxProtocolVersion_w(rtc::SSLProtocolVersion version) {
-    return false;
-  }
-
  private:
   struct ChannelMapEntry {
-    ChannelMapEntry() : impl_(NULL), candidates_allocated_(false), ref_(0) {}
+    ChannelMapEntry() : impl_(NULL), ref_(0) {}
     explicit ChannelMapEntry(TransportChannelImpl *impl)
         : impl_(impl),
-          candidates_allocated_(false),
           ref_(0) {
     }
 
     void AddRef() { ++ref_; }
     void DecRef() {
       ASSERT(ref_ > 0);
       --ref_;
     }
     int ref() const { return ref_; }
 
     TransportChannelImpl* get() const { return impl_; }
     TransportChannelImpl* operator->() const  { return impl_; }
-    void set_candidates_allocated(bool status) {
-      candidates_allocated_ = status;
-    }
-    bool candidates_allocated() const { return candidates_allocated_; }
 
-  private:
-    TransportChannelImpl *impl_;
-    bool candidates_allocated_;
+   private:
+    TransportChannelImpl* impl_;
     int ref_;
   };
 
   // Candidate component => ChannelMapEntry
   typedef std::map<int, ChannelMapEntry> ChannelMap;
 
   // Called when the state of a channel changes.
   void OnChannelReadableState(TransportChannel* channel);
   void OnChannelWritableState(TransportChannel* channel);
 
   // Called when the receiving state of a channel changes.
   void OnChannelReceivingState(TransportChannel* channel);
 
-  // Called when a channel requests signaling.
-  void OnChannelRequestSignaling(TransportChannelImpl* channel);
+  // Called when a channel starts allocating candidates for a new ICE session
+  void OnChannelCandidatesAllocationStarted(TransportChannelImpl* channel);
 
-  // Called when a candidate is ready from remote peer.
-  void OnRemoteCandidate(const Candidate& candidate);
   // Called when a candidate is ready from channel.
   void OnChannelCandidateReady(TransportChannelImpl* channel,
                                const Candidate& candidate);
   void OnChannelRouteChange(TransportChannel* channel,
                             const Candidate& remote_candidate);
   void OnChannelCandidatesAllocationDone(TransportChannelImpl* channel);
   // Called when there is ICE role change.
   void OnRoleConflict(TransportChannelImpl* channel);
   // Called when the channel removes a connection.
   void OnChannelConnectionRemoved(TransportChannelImpl* channel);
 
-  // Dispatches messages to the appropriate handler (below).
-  void OnMessage(rtc::Message* msg);
-
-  // These are versions of the above methods that are called only on a
-  // particular thread (s = signaling, w = worker).  The above methods post or
-  // send a message to invoke this version.
-  TransportChannelImpl* CreateChannel_w(int component);
-  void DestroyChannel_w(int component);
-  void ConnectChannels_w();
-  void ResetChannels_w();
-  void DestroyAllChannels_w();
-  void OnRemoteCandidate_w(const Candidate& candidate);
-  void OnChannelReadableState_s();
-  void OnChannelWritableState_s();
-  void OnChannelReceivingState_s();
-  void OnChannelRequestSignaling_s();
-  void OnConnecting_s();
-  void OnChannelRouteChange_s(const TransportChannel* channel,
-                              const Candidate& remote_candidate);
-  void OnChannelCandidatesAllocationDone_s();
-
   // Helper function that invokes the given function on every channel.
   typedef void (TransportChannelImpl::* TransportChannelFunc)();
-  void CallChannels_w(TransportChannelFunc func);
+  void CallChannels(TransportChannelFunc func);
 
   // Computes the AND and OR of the channel's read/write/receiving state
   // (argument picks the operation).
-  TransportState GetTransportState_s(TransportStateType type);
-
-  void OnChannelCandidateReady_s();
-
-  void SetIceRole_w(IceRole role);
-  void SetRemoteIceMode_w(IceMode mode);
-  bool SetLocalTransportDescription_w(const TransportDescription& desc,
-                                      ContentAction action,
-                                      std::string* error_desc);
-  bool SetRemoteTransportDescription_w(const TransportDescription& desc,
-                                       ContentAction action,
-                                       std::string* error_desc);
-  bool GetStats_w(TransportStats* infos);
-  bool GetRemoteCertificate_w(rtc::SSLCertificate** cert);
-
-  void SetChannelReceivingTimeout_w(int timeout_ms);
+  TransportState GetTransportState(TransportStateType type);
 
   // Sends SignalCompleted if we are now in that state.
-  void MaybeCompleted_w();
+  void CheckIfCompleted();
 
-  rtc::Thread* const signaling_thread_;
-  rtc::Thread* const worker_thread_;
+  // Sends SignalCandidatesAllocationDone if all channels are done
+  void CheckIfCandidatesAllocationDone();
+
+  void UpdateReadableState();
+  void UpdateWritableState();
+  void UpdateReceivingState();
+
   const std::string content_name_;
   const std::string type_;
   PortAllocator* const allocator_;
   bool destroyed_;
   TransportState readable_;
   TransportState writable_;
   TransportState receiving_;
   bool was_writable_;
   bool connect_requested_;
   IceRole ice_role_;
   uint64 tiebreaker_;
   TransportProtocol protocol_;
   IceMode remote_ice_mode_;
   int channel_receiving_timeout_;
   rtc::scoped_ptr<TransportDescription> local_description_;
   rtc::scoped_ptr<TransportDescription> remote_description_;
+  bool local_description_set_;
+  bool remote_description_set_;
+  CandidateGatheringState candidate_gathering_state_;
 
-  // TODO(tommi): Make sure we only use this on the worker thread.
   ChannelMap channels_;
   // Buffers the ready_candidates so that SignalCanidatesReady can
   // provide them in multiples.
   std::vector<Candidate> ready_candidates_;
-  // Protects changes to channels and messages
-  rtc::CriticalSection crit_;
 
   DISALLOW_COPY_AND_ASSIGN(Transport);
 };
 
 // Extract a TransportProtocol from a TransportDescription.
 TransportProtocol TransportProtocolFromDescription(
     const TransportDescription* desc);
 
 }  // namespace cricket
 
 #endif  // WEBRTC_P2P_BASE_TRANSPORT_H_