media/midi/midi_manager.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/midi/midi_manager.h"
   6
   7 #include "base/bind.h"
   8 #include "base/message_loop/message_loop.h"
   9 #include "base/message_loop/message_loop_proxy.h"
  10 #include "base/trace_event/trace_event.h"
  11
  12 namespace media {
  13
  14 MidiManager::MidiManager()
  15     : initialized_(false),
  16       result_(MIDI_NOT_SUPPORTED) {
  17 }
  18
  19 MidiManager::~MidiManager() {
  20 }
  21
  22 #if !defined(OS_MACOSX) && !defined(OS_WIN) && !defined(USE_ALSA) && \
  23     !defined(OS_ANDROID) && !defined(OS_CHROMEOS)
  24 MidiManager* MidiManager::Create() {
  25   return new MidiManager;
  26 }
  27 #endif
  28
  29 void MidiManager::StartSession(MidiManagerClient* client) {
  30   bool session_is_ready;
  31   bool session_needs_initialization = false;
  32   bool too_many_pending_clients_exist = false;
  33
  34   {
  35     base::AutoLock auto_lock(lock_);
  36     session_is_ready = initialized_;
  37     if (clients_.find(client) != clients_.end() ||
  38         pending_clients_.find(client) != pending_clients_.end()) {
  39       // Should not happen. But just in case the renderer is compromised.
  40       NOTREACHED();
  41       return;
  42     }
  43     if (!session_is_ready) {
  44       // Do not accept a new request if the pending client list contains too
  45       // many clients.
  46       too_many_pending_clients_exist =
  47           pending_clients_.size() >= kMaxPendingClientCount;
  48
  49       if (!too_many_pending_clients_exist) {
  50         // Call StartInitialization() only for the first request.
  51         session_needs_initialization = pending_clients_.empty();
  52         pending_clients_.insert(client);
  53       }
  54     }
  55   }
  56
  57   // Lazily initialize the MIDI back-end.
  58   if (!session_is_ready) {
  59     if (session_needs_initialization) {
  60       TRACE_EVENT0("midi", "MidiManager::StartInitialization");
  61       session_thread_runner_ =
  62           base::MessageLoop::current()->message_loop_proxy();
  63       StartInitialization();
  64     }
  65     if (too_many_pending_clients_exist) {
  66       // Return an error immediately if there are too many requests.
  67       client->CompleteStartSession(MIDI_INITIALIZATION_ERROR);
  68       return;
  69     }
  70     // CompleteInitialization() will be called asynchronously when platform
  71     // dependent initialization is finished.
  72     return;
  73   }
  74
  75   // Platform dependent initialization was already finished for previously
  76   // initialized clients.
  77   MidiResult result;
  78   {
  79     base::AutoLock auto_lock(lock_);
  80     if (result_ == MIDI_OK) {
  81       AddInitialPorts(client);
  82       clients_.insert(client);
  83     }
  84     result = result_;
  85   }
  86   client->CompleteStartSession(result);
  87 }
  88
  89 void MidiManager::EndSession(MidiManagerClient* client) {
  90   // At this point, |client| can be in the destruction process, and calling
  91   // any method of |client| is dangerous.
  92   base::AutoLock auto_lock(lock_);
  93   clients_.erase(client);
  94   pending_clients_.erase(client);
  95 }
  96
  97 void MidiManager::DispatchSendMidiData(MidiManagerClient* client,
  98                                        uint32 port_index,
  99                                        const std::vector<uint8>& data,
 100                                        double timestamp) {
 101   NOTREACHED();
 102 }
 103
 104 void MidiManager::StartInitialization() {
 105   CompleteInitialization(MIDI_NOT_SUPPORTED);
 106 }
 107
 108 void MidiManager::CompleteInitialization(MidiResult result) {
 109   DCHECK(session_thread_runner_.get());
 110   // It is safe to post a task to the IO thread from here because the IO thread
 111   // should have stopped if the MidiManager is going to be destructed.
 112   session_thread_runner_->PostTask(
 113       FROM_HERE,
 114       base::Bind(&MidiManager::CompleteInitializationInternal,
 115                  base::Unretained(this),
 116                  result));
 117 }
 118
 119 void MidiManager::AddInputPort(const MidiPortInfo& info) {
 120   base::AutoLock auto_lock(lock_);
 121   input_ports_.push_back(info);
 122   for (auto client : clients_)
 123     client->AddInputPort(info);
 124 }
 125
 126 void MidiManager::AddOutputPort(const MidiPortInfo& info) {
 127   base::AutoLock auto_lock(lock_);
 128   output_ports_.push_back(info);
 129   for (auto client : clients_)
 130     client->AddOutputPort(info);
 131 }
 132
 133 void MidiManager::ReceiveMidiData(
 134     uint32 port_index,
 135     const uint8* data,
 136     size_t length,
 137     double timestamp) {
 138   base::AutoLock auto_lock(lock_);
 139
 140   for (auto client : clients_)
 141     client->ReceiveMidiData(port_index, data, length, timestamp);
 142 }
 143
 144 void MidiManager::CompleteInitializationInternal(MidiResult result) {
 145   TRACE_EVENT0("midi", "MidiManager::CompleteInitialization");
 146
 147   base::AutoLock auto_lock(lock_);
 148   DCHECK(clients_.empty());
 149   DCHECK(!initialized_);
 150   initialized_ = true;
 151   result_ = result;
 152
 153   for (auto client : pending_clients_) {
 154     if (result_ == MIDI_OK) {
 155       AddInitialPorts(client);
 156       clients_.insert(client);
 157     }
 158     client->CompleteStartSession(result_);
 159   }
 160   pending_clients_.clear();
 161 }
 162
 163 void MidiManager::AddInitialPorts(MidiManagerClient* client) {
 164   lock_.AssertAcquired();
 165
 166   for (const auto& info : input_ports_)
 167     client->AddInputPort(info);
 168   for (const auto& info : output_ports_)
 169     client->AddOutputPort(info);
 170 }
 171
 172 }  // namespace media