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/trace_event/trace_event.h"
  10
  11 namespace media {
  12 namespace midi {
  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) && \
  23     !(defined(USE_ALSA) && defined(USE_UDEV)) && !defined(OS_ANDROID)
  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()->task_runner();
  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::AccumulateMidiBytesSent(MidiManagerClient* client, size_t n) {
  98   {
  99     base::AutoLock auto_lock(lock_);
 100     if (clients_.find(client) == clients_.end())
 101       return;
 102   }
 103   client->AccumulateMidiBytesSent(n);
 104 }
 105
 106 void MidiManager::DispatchSendMidiData(MidiManagerClient* client,
 107                                        uint32 port_index,
 108                                        const std::vector<uint8>& data,
 109                                        double timestamp) {
 110   NOTREACHED();
 111 }
 112
 113 void MidiManager::StartInitialization() {
 114   CompleteInitialization(MIDI_NOT_SUPPORTED);
 115 }
 116
 117 void MidiManager::CompleteInitialization(MidiResult result) {
 118   DCHECK(session_thread_runner_.get());
 119   // It is safe to post a task to the IO thread from here because the IO thread
 120   // should have stopped if the MidiManager is going to be destructed.
 121   session_thread_runner_->PostTask(
 122       FROM_HERE,
 123       base::Bind(&MidiManager::CompleteInitializationInternal,
 124                  base::Unretained(this),
 125                  result));
 126 }
 127
 128 void MidiManager::AddInputPort(const MidiPortInfo& info) {
 129   base::AutoLock auto_lock(lock_);
 130   input_ports_.push_back(info);
 131   for (auto client : clients_)
 132     client->AddInputPort(info);
 133 }
 134
 135 void MidiManager::AddOutputPort(const MidiPortInfo& info) {
 136   base::AutoLock auto_lock(lock_);
 137   output_ports_.push_back(info);
 138   for (auto client : clients_)
 139     client->AddOutputPort(info);
 140 }
 141
 142 void MidiManager::SetInputPortState(uint32 port_index, MidiPortState state) {
 143   base::AutoLock auto_lock(lock_);
 144   DCHECK_LT(port_index, input_ports_.size());
 145   input_ports_[port_index].state = state;
 146   for (auto client : clients_)
 147     client->SetInputPortState(port_index, state);
 148 }
 149
 150 void MidiManager::SetOutputPortState(uint32 port_index, MidiPortState state) {
 151   base::AutoLock auto_lock(lock_);
 152   DCHECK_LT(port_index, output_ports_.size());
 153   output_ports_[port_index].state = state;
 154   for (auto client : clients_)
 155     client->SetOutputPortState(port_index, state);
 156 }
 157
 158 void MidiManager::ReceiveMidiData(
 159     uint32 port_index,
 160     const uint8* data,
 161     size_t length,
 162     double timestamp) {
 163   base::AutoLock auto_lock(lock_);
 164
 165   for (auto client : clients_)
 166     client->ReceiveMidiData(port_index, data, length, timestamp);
 167 }
 168
 169 void MidiManager::CompleteInitializationInternal(MidiResult result) {
 170   TRACE_EVENT0("midi", "MidiManager::CompleteInitialization");
 171
 172   base::AutoLock auto_lock(lock_);
 173   DCHECK(clients_.empty());
 174   DCHECK(!initialized_);
 175   initialized_ = true;
 176   result_ = result;
 177
 178   for (auto client : pending_clients_) {
 179     if (result_ == MIDI_OK) {
 180       AddInitialPorts(client);
 181       clients_.insert(client);
 182     }
 183     client->CompleteStartSession(result_);
 184   }
 185   pending_clients_.clear();
 186 }
 187
 188 void MidiManager::AddInitialPorts(MidiManagerClient* client) {
 189   lock_.AssertAcquired();
 190
 191   for (const auto& info : input_ports_)
 192     client->AddInputPort(info);
 193   for (const auto& info : output_ports_)
 194     client->AddOutputPort(info);
 195 }
 196
 197 }  // namespace midi
 198 }  // namespace media