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      1 /*
      2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #ifndef WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_H
     12 #define WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_H
     13 
     14 #include <vector>
     15 
     16 #include "webrtc/base/constructormagic.h"
     17 #include "webrtc/base/scoped_ptr.h"
     18 #include "webrtc/call/rtc_event_log.h"
     19 #include "webrtc/system_wrappers/include/atomic32.h"
     20 #include "webrtc/system_wrappers/include/critical_section_wrapper.h"
     21 #include "webrtc/typedefs.h"
     22 
     23 namespace webrtc {
     24 
     25 class Config;
     26 
     27 namespace voe {
     28 
     29 class Channel;
     30 
     31 // Shared-pointer implementation for keeping track of Channels. The underlying
     32 // shared instance will be dropped when no more ChannelOwners point to it.
     33 //
     34 // One common source of ChannelOwner instances are
     35 // ChannelManager::CreateChannel() and ChannelManager::GetChannel(...).
     36 // It has a similar use case to shared_ptr in C++11. Should this move to C++11
     37 // in the future, this class should be replaced by exactly that.
     38 //
     39 // To access the underlying Channel, use .channel().
     40 // IsValid() implements a convenience method as an alternative for checking
     41 // whether the underlying pointer is NULL or not.
     42 //
     43 // Channel channel_owner = channel_manager.GetChannel(channel_id);
     44 // if (channel_owner.IsValid())
     45 //   channel_owner.channel()->...;
     46 //
     47 class ChannelOwner {
     48  public:
     49   explicit ChannelOwner(Channel* channel);
     50   ChannelOwner(const ChannelOwner& channel_owner);
     51 
     52   ~ChannelOwner();
     53 
     54   ChannelOwner& operator=(const ChannelOwner& other);
     55 
     56   Channel* channel() const { return channel_ref_->channel.get(); }
     57   bool IsValid() { return channel_ref_->channel.get() != NULL; }
     58   int use_count() const { return channel_ref_->ref_count.Value(); }
     59  private:
     60   // Shared instance of a Channel. Copying ChannelOwners increase the reference
     61   // count and destroying ChannelOwners decrease references. Channels are
     62   // deleted when no references to them are held.
     63   struct ChannelRef {
     64     ChannelRef(Channel* channel);
     65     const rtc::scoped_ptr<Channel> channel;
     66     Atomic32 ref_count;
     67   };
     68 
     69   ChannelRef* channel_ref_;
     70 };
     71 
     72 class ChannelManager {
     73  public:
     74   ChannelManager(uint32_t instance_id, const Config& config);
     75 
     76   // Upon construction of an Iterator it will grab a copy of the channel list of
     77   // the ChannelManager. The iteration will then occur over this state, not the
     78   // current one of the ChannelManager. As the Iterator holds its own references
     79   // to the Channels, they will remain valid even if they are removed from the
     80   // ChannelManager.
     81   class Iterator {
     82    public:
     83     explicit Iterator(ChannelManager* channel_manager);
     84 
     85     Channel* GetChannel();
     86     bool IsValid();
     87 
     88     void Increment();
     89 
     90    private:
     91     size_t iterator_pos_;
     92     std::vector<ChannelOwner> channels_;
     93 
     94     RTC_DISALLOW_COPY_AND_ASSIGN(Iterator);
     95   };
     96 
     97   // CreateChannel will always return a valid ChannelOwner instance. The channel
     98   // is created either based on internal configuration, i.e. |config_|, by
     99   // calling CreateChannel(), or using and external configuration
    100   // |external_config| if the overloaded method
    101   // CreateChannel(const Config& external_config) is called.
    102   ChannelOwner CreateChannel();
    103   ChannelOwner CreateChannel(const Config& external_config);
    104 
    105   // ChannelOwner.channel() will be NULL if channel_id is invalid or no longer
    106   // exists. This should be checked with ChannelOwner::IsValid().
    107   ChannelOwner GetChannel(int32_t channel_id);
    108   void GetAllChannels(std::vector<ChannelOwner>* channels);
    109 
    110   void DestroyChannel(int32_t channel_id);
    111   void DestroyAllChannels();
    112 
    113   size_t NumOfChannels() const;
    114 
    115   // Returns a pointer to the event log object stored within the ChannelManager.
    116   RtcEventLog* GetEventLog() const;
    117 
    118  private:
    119   // Create a channel given a configuration, |config|.
    120   ChannelOwner CreateChannelInternal(const Config& config);
    121 
    122   uint32_t instance_id_;
    123 
    124   Atomic32 last_channel_id_;
    125 
    126   rtc::scoped_ptr<CriticalSectionWrapper> lock_;
    127   std::vector<ChannelOwner> channels_;
    128 
    129   const Config& config_;
    130   rtc::scoped_ptr<RtcEventLog> event_log_;
    131 
    132   RTC_DISALLOW_COPY_AND_ASSIGN(ChannelManager);
    133 };
    134 }  // namespace voe
    135 }  // namespace webrtc
    136 
    137 #endif  // WEBRTC_VOICE_ENGINE_CHANNEL_MANAGER_H
    138