1 /* 2 * libjingle 3 * Copyright 2004--2010, Google Inc. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #ifndef TALK_SOUND_AUTOMATICALLYCHOSENSOUNDSYSTEM_H_ 29 #define TALK_SOUND_AUTOMATICALLYCHOSENSOUNDSYSTEM_H_ 30 31 #include "talk/base/common.h" 32 #include "talk/base/logging.h" 33 #include "talk/base/scoped_ptr.h" 34 #include "talk/sound/soundsysteminterface.h" 35 #include "talk/sound/soundsystemproxy.h" 36 37 namespace cricket { 38 39 // A function type that creates an instance of a sound system implementation. 40 typedef SoundSystemInterface *(*SoundSystemCreator)(); 41 42 // An AutomaticallyChosenSoundSystem is a sound system proxy that defers to 43 // an instance of the first sound system implementation in a list that 44 // successfully initializes. 45 template <const SoundSystemCreator kSoundSystemCreators[], int kNumSoundSystems> 46 class AutomaticallyChosenSoundSystem : public SoundSystemProxy { 47 public: 48 // Chooses and initializes the underlying sound system. 49 virtual bool Init(); 50 // Terminates the underlying sound system implementation, but caches it for 51 // future re-use. 52 virtual void Terminate(); 53 54 virtual const char *GetName() const; 55 56 private: 57 talk_base::scoped_ptr<SoundSystemInterface> sound_systems_[kNumSoundSystems]; 58 }; 59 60 template <const SoundSystemCreator kSoundSystemCreators[], int kNumSoundSystems> 61 bool AutomaticallyChosenSoundSystem<kSoundSystemCreators, 62 kNumSoundSystems>::Init() { 63 if (wrapped_) { 64 return true; 65 } 66 for (int i = 0; i < kNumSoundSystems; ++i) { 67 if (!sound_systems_[i].get()) { 68 sound_systems_[i].reset((*kSoundSystemCreators[i])()); 69 } 70 if (sound_systems_[i]->Init()) { 71 // This is the first sound system in the list to successfully 72 // initialize, so we're done. 73 wrapped_ = sound_systems_[i].get(); 74 break; 75 } 76 // Else it failed to initialize, so try the remaining ones. 77 } 78 if (!wrapped_) { 79 LOG(LS_ERROR) << "Failed to find a usable sound system"; 80 return false; 81 } 82 LOG(LS_INFO) << "Selected " << wrapped_->GetName() << " sound system"; 83 return true; 84 } 85 86 template <const SoundSystemCreator kSoundSystemCreators[], int kNumSoundSystems> 87 void AutomaticallyChosenSoundSystem<kSoundSystemCreators, 88 kNumSoundSystems>::Terminate() { 89 if (!wrapped_) { 90 return; 91 } 92 wrapped_->Terminate(); 93 wrapped_ = NULL; 94 // We do not free the scoped_ptrs because we may be re-init'ed soon. 95 } 96 97 template <const SoundSystemCreator kSoundSystemCreators[], int kNumSoundSystems> 98 const char *AutomaticallyChosenSoundSystem<kSoundSystemCreators, 99 kNumSoundSystems>::GetName() const { 100 return wrapped_ ? wrapped_->GetName() : "automatic"; 101 } 102 103 } // namespace cricket 104 105 #endif // TALK_SOUND_AUTOMATICALLYCHOSENSOUNDSYSTEM_H_ 106