dom/gamepad/GamepadPlatformService.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "mozilla/dom/GamepadPlatformService.h"
   8
   9 #include "mozilla/dom/GamepadEventChannelParent.h"
  10 #include "mozilla/dom/GamepadMonitoring.h"
  11 #include "mozilla/dom/GamepadTestChannelParent.h"
  12 #include "mozilla/ipc/BackgroundParent.h"
  13 #include "mozilla/Mutex.h"
  14 #include "mozilla/Unused.h"
  15
  16 #include "nsCOMPtr.h"
  17 #include "nsHashKeys.h"
  18
  19 using namespace mozilla::ipc;
  20
  21 namespace mozilla::dom {
  22
  23 namespace {
  24
  25 // This is the singleton instance of GamepadPlatformService, can be called
  26 // by both background and monitor thread.
  27 StaticRefPtr<GamepadPlatformService> gGamepadPlatformServiceSingleton;
  28
  29 }  // namespace
  30
  31 // static
  32 GamepadMonitoringState& GamepadMonitoringState::GetSingleton() {
  33   static GamepadMonitoringState sInstance{};
  34   return sInstance;
  35 }
  36
  37 void GamepadMonitoringState::AddObserver(GamepadTestChannelParent* aParent) {
  38   AssertIsOnBackgroundThread();
  39   MOZ_ASSERT(aParent);
  40   MOZ_ALWAYS_TRUE(mObservers.append(aParent));
  41 }
  42
  43 void GamepadMonitoringState::RemoveObserver(GamepadTestChannelParent* aParent) {
  44   AssertIsOnBackgroundThread();
  45   MOZ_ASSERT(aParent);
  46
  47   WeakPtr<GamepadTestChannelParent>* observer = nullptr;
  48
  49   for (auto& item : mObservers) {
  50     if (item == aParent) {
  51       observer = &item;
  52     }
  53   }
  54
  55   MOZ_ASSERT(
  56       observer,
  57       "Attempted to remove a GamepadTestChannelParent that was never added");
  58
  59   std::swap(*observer, mObservers.back());
  60   mObservers.popBack();
  61 }
  62
  63 bool GamepadMonitoringState::IsMonitoring() const {
  64   AssertIsOnBackgroundThread();
  65   return mIsMonitoring;
  66 }
  67
  68 void GamepadMonitoringState::Set(bool aIsMonitoring) {
  69   AssertIsOnBackgroundThread();
  70
  71   if (mIsMonitoring != aIsMonitoring) {
  72     mIsMonitoring = aIsMonitoring;
  73     for (auto& observer : mObservers) {
  74       // Since each GamepadTestChannelParent removes itself in its dtor, this
  75       // should never be nullptr
  76       MOZ_RELEASE_ASSERT(observer);
  77       observer->OnMonitoringStateChanged(aIsMonitoring);
  78     }
  79   }
  80 }
  81
  82 GamepadPlatformService::GamepadPlatformService()
  83     : mNextGamepadHandleValue(1),
  84       mMutex("mozilla::dom::GamepadPlatformService") {}
  85
  86 GamepadPlatformService::~GamepadPlatformService() { Cleanup(); }
  87
  88 // static
  89 already_AddRefed<GamepadPlatformService>
  90 GamepadPlatformService::GetParentService() {
  91   // GamepadPlatformService can only be accessed in parent process
  92   MOZ_ASSERT(XRE_IsParentProcess());
  93   if (!gGamepadPlatformServiceSingleton) {
  94     // Only Background Thread can create new GamepadPlatformService instance.
  95     if (IsOnBackgroundThread()) {
  96       gGamepadPlatformServiceSingleton = new GamepadPlatformService();
  97     } else {
  98       return nullptr;
  99     }
 100   }
 101   RefPtr<GamepadPlatformService> service(gGamepadPlatformServiceSingleton);
 102   return service.forget();
 103 }
 104
 105 template <class T>
 106 void GamepadPlatformService::NotifyGamepadChange(GamepadHandle aHandle,
 107                                                  const T& aInfo) {
 108   // This method is called by monitor populated in
 109   // platform-dependent backends
 110   MOZ_ASSERT(XRE_IsParentProcess());
 111   MOZ_ASSERT(!NS_IsMainThread());
 112
 113   GamepadChangeEventBody body(aInfo);
 114   GamepadChangeEvent e(aHandle, body);
 115
 116   // mChannelParents may be accessed by background thread in the
 117   // same time, we use mutex to prevent possible race condtion
 118   MutexAutoLock autoLock(mMutex);
 119
 120   for (uint32_t i = 0; i < mChannelParents.Length(); ++i) {
 121     mChannelParents[i]->DispatchUpdateEvent(e);
 122   }
 123 }
 124
 125 GamepadHandle GamepadPlatformService::AddGamepad(
 126     const char* aID, GamepadMappingType aMapping, GamepadHand aHand,
 127     uint32_t aNumButtons, uint32_t aNumAxes, uint32_t aHaptics,
 128     uint32_t aNumLightIndicator, uint32_t aNumTouchEvents) {
 129   // This method is called by monitor thread populated in
 130   // platform-dependent backends
 131   MOZ_ASSERT(XRE_IsParentProcess());
 132   MOZ_ASSERT(!NS_IsMainThread());
 133
 134   GamepadHandle gamepadHandle{mNextGamepadHandleValue++,
 135                               GamepadHandleKind::GamepadPlatformManager};
 136
 137   // Only VR controllers has displayID, we give 0 to the general gamepads.
 138   GamepadAdded a(NS_ConvertUTF8toUTF16(nsDependentCString(aID)), aMapping,
 139                  aHand, 0, aNumButtons, aNumAxes, aHaptics, aNumLightIndicator,
 140                  aNumTouchEvents);
 141
 142   mGamepadAdded.emplace(gamepadHandle, a);
 143   NotifyGamepadChange<GamepadAdded>(gamepadHandle, a);
 144   return gamepadHandle;
 145 }
 146
 147 void GamepadPlatformService::RemoveGamepad(GamepadHandle aHandle) {
 148   // This method is called by monitor thread populated in
 149   // platform-dependent backends
 150   MOZ_ASSERT(XRE_IsParentProcess());
 151   MOZ_ASSERT(!NS_IsMainThread());
 152   GamepadRemoved a;
 153   NotifyGamepadChange<GamepadRemoved>(aHandle, a);
 154   mGamepadAdded.erase(aHandle);
 155 }
 156
 157 void GamepadPlatformService::NewButtonEvent(GamepadHandle aHandle,
 158                                             uint32_t aButton, bool aPressed,
 159                                             bool aTouched, double aValue) {
 160   // This method is called by monitor thread populated in
 161   // platform-dependent backends
 162   MOZ_ASSERT(XRE_IsParentProcess());
 163   MOZ_ASSERT(!NS_IsMainThread());
 164   GamepadButtonInformation a(aButton, aValue, aPressed, aTouched);
 165   NotifyGamepadChange<GamepadButtonInformation>(aHandle, a);
 166 }
 167
 168 void GamepadPlatformService::NewButtonEvent(GamepadHandle aHandle,
 169                                             uint32_t aButton, bool aPressed,
 170                                             double aValue) {
 171   // This method is called by monitor thread populated in
 172   // platform-dependent backends
 173   MOZ_ASSERT(XRE_IsParentProcess());
 174   MOZ_ASSERT(!NS_IsMainThread());
 175   // When only a digital button is available the value will be synthesized.
 176   NewButtonEvent(aHandle, aButton, aPressed, aPressed, aValue);
 177 }
 178
 179 void GamepadPlatformService::NewButtonEvent(GamepadHandle aHandle,
 180                                             uint32_t aButton, bool aPressed,
 181                                             bool aTouched) {
 182   // This method is called by monitor thread populated in
 183   // platform-dependent backends
 184   MOZ_ASSERT(XRE_IsParentProcess());
 185   MOZ_ASSERT(!NS_IsMainThread());
 186   // When only a digital button is available the value will be synthesized.
 187   NewButtonEvent(aHandle, aButton, aPressed, aTouched, aPressed ? 1.0L : 0.0L);
 188 }
 189
 190 void GamepadPlatformService::NewButtonEvent(GamepadHandle aHandle,
 191                                             uint32_t aButton, bool aPressed) {
 192   // This method is called by monitor thread populated in
 193   // platform-dependent backends
 194   MOZ_ASSERT(XRE_IsParentProcess());
 195   MOZ_ASSERT(!NS_IsMainThread());
 196   // When only a digital button is available the value will be synthesized.
 197   NewButtonEvent(aHandle, aButton, aPressed, aPressed, aPressed ? 1.0L : 0.0L);
 198 }
 199
 200 void GamepadPlatformService::NewAxisMoveEvent(GamepadHandle aHandle,
 201                                               uint32_t aAxis, double aValue) {
 202   // This method is called by monitor thread populated in
 203   // platform-dependent backends
 204   MOZ_ASSERT(XRE_IsParentProcess());
 205   MOZ_ASSERT(!NS_IsMainThread());
 206   GamepadAxisInformation a(aAxis, aValue);
 207   NotifyGamepadChange<GamepadAxisInformation>(aHandle, a);
 208 }
 209
 210 void GamepadPlatformService::NewLightIndicatorTypeEvent(
 211     GamepadHandle aHandle, uint32_t aLight, GamepadLightIndicatorType aType) {
 212   // This method is called by monitor thread populated in
 213   // platform-dependent backends
 214   MOZ_ASSERT(XRE_IsParentProcess());
 215   MOZ_ASSERT(!NS_IsMainThread());
 216   GamepadLightIndicatorTypeInformation a(aLight, aType);
 217   NotifyGamepadChange<GamepadLightIndicatorTypeInformation>(aHandle, a);
 218 }
 219
 220 void GamepadPlatformService::NewPoseEvent(GamepadHandle aHandle,
 221                                           const GamepadPoseState& aState) {
 222   // This method is called by monitor thread populated in
 223   // platform-dependent backends
 224   MOZ_ASSERT(XRE_IsParentProcess());
 225   MOZ_ASSERT(!NS_IsMainThread());
 226   GamepadPoseInformation a(aState);
 227   NotifyGamepadChange<GamepadPoseInformation>(aHandle, a);
 228 }
 229
 230 void GamepadPlatformService::NewMultiTouchEvent(
 231     GamepadHandle aHandle, uint32_t aTouchArrayIndex,
 232     const GamepadTouchState& aState) {
 233   // This method is called by monitor thread populated in
 234   // platform-dependent backends
 235   MOZ_ASSERT(XRE_IsParentProcess());
 236   MOZ_ASSERT(!NS_IsMainThread());
 237
 238   GamepadTouchInformation a(aTouchArrayIndex, aState);
 239   NotifyGamepadChange<GamepadTouchInformation>(aHandle, a);
 240 }
 241
 242 void GamepadPlatformService::ResetGamepadIndexes() {
 243   // This method is called by monitor thread populated in
 244   // platform-dependent backends
 245   MOZ_ASSERT(XRE_IsParentProcess());
 246   MOZ_ASSERT(!NS_IsMainThread());
 247   mNextGamepadHandleValue = 1;
 248 }
 249
 250 void GamepadPlatformService::AddChannelParent(
 251     GamepadEventChannelParent* aParent) {
 252   // mChannelParents can only be modified once GamepadEventChannelParent
 253   // is created or removed in Background thread
 254   AssertIsOnBackgroundThread();
 255   MOZ_ASSERT(aParent);
 256   MOZ_ASSERT(!mChannelParents.Contains(aParent));
 257
 258   // We use mutex here to prevent race condition with monitor thread
 259   {
 260     MutexAutoLock autoLock(mMutex);
 261     mChannelParents.AppendElement(aParent);
 262
 263     // For a new GamepadEventChannel, we have to send the exising GamepadAdded
 264     // to it to make it can have the same amount of gamepads with others.
 265     if (mChannelParents.Length() > 1) {
 266       for (const auto& evt : mGamepadAdded) {
 267         GamepadChangeEventBody body(evt.second);
 268         GamepadChangeEvent e(evt.first, body);
 269         aParent->DispatchUpdateEvent(e);
 270       }
 271     }
 272   }
 273
 274   StartGamepadMonitoring();
 275
 276   GamepadMonitoringState::GetSingleton().Set(true);
 277 }
 278
 279 void GamepadPlatformService::RemoveChannelParent(
 280     GamepadEventChannelParent* aParent) {
 281   // mChannelParents can only be modified once GamepadEventChannelParent
 282   // is created or removed in Background thread
 283   AssertIsOnBackgroundThread();
 284   MOZ_ASSERT(aParent);
 285   MOZ_ASSERT(mChannelParents.Contains(aParent));
 286
 287   // We use mutex here to prevent race condition with monitor thread
 288   {
 289     MutexAutoLock autoLock(mMutex);
 290     mChannelParents.RemoveElement(aParent);
 291     if (!mChannelParents.IsEmpty()) {
 292       return;
 293     }
 294   }
 295
 296   GamepadMonitoringState::GetSingleton().Set(false);
 297
 298   StopGamepadMonitoring();
 299   ResetGamepadIndexes();
 300   MaybeShutdown();
 301 }
 302
 303 void GamepadPlatformService::MaybeShutdown() {
 304   // This method is invoked in MaybeStopGamepadMonitoring when
 305   // an IPDL channel is going to be destroyed
 306   AssertIsOnBackgroundThread();
 307
 308   // We have to release gGamepadPlatformServiceSingleton ouside
 309   // the mutex as well as making upcoming GetParentService() call
 310   // recreate new singleton, so we use this RefPtr to temporarily
 311   // hold the reference, postponing the release process until this
 312   // method ends.
 313   RefPtr<GamepadPlatformService> kungFuDeathGrip;
 314
 315   bool isChannelParentEmpty;
 316   {
 317     MutexAutoLock autoLock(mMutex);
 318     isChannelParentEmpty = mChannelParents.IsEmpty();
 319     if (isChannelParentEmpty) {
 320       kungFuDeathGrip = gGamepadPlatformServiceSingleton;
 321       gGamepadPlatformServiceSingleton = nullptr;
 322       mGamepadAdded.clear();
 323     }
 324   }
 325 }
 326
 327 void GamepadPlatformService::Cleanup() {
 328   // This method is called when GamepadPlatformService is
 329   // successfully distructed in background thread
 330   AssertIsOnBackgroundThread();
 331
 332   MutexAutoLock autoLock(mMutex);
 333   mChannelParents.Clear();
 334 }
 335
 336 }  // namespace mozilla::dom