hal/HalWakeLock.cpp

   1 /* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   4  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "mozilla/Hal.h"
   7 #include "mozilla/HalWakeLock.h"
   8 #include "mozilla/Services.h"
   9 #include "mozilla/StaticPtr.h"
  10 #include "mozilla/dom/ContentParent.h"
  11 #include "nsClassHashtable.h"
  12 #include "nsDataHashtable.h"
  13 #include "nsHashKeys.h"
  14 #include "nsIPropertyBag2.h"
  15 #include "nsIObserverService.h"
  16
  17 using namespace mozilla;
  18 using namespace mozilla::hal;
  19
  20 namespace {
  21
  22 struct LockCount {
  23   LockCount()
  24     : numLocks(0)
  25     , numHidden(0)
  26   {}
  27   uint32_t numLocks;
  28   uint32_t numHidden;
  29   nsTArray<uint64_t> processes;
  30 };
  31
  32 typedef nsDataHashtable<nsUint64HashKey, LockCount> ProcessLockTable;
  33 typedef nsClassHashtable<nsStringHashKey, ProcessLockTable> LockTable;
  34
  35 int sActiveListeners = 0;
  36 StaticAutoPtr<LockTable> sLockTable;
  37 bool sInitialized = false;
  38 bool sIsShuttingDown = false;
  39
  40 WakeLockInformation
  41 WakeLockInfoFromLockCount(const nsAString& aTopic, const LockCount& aLockCount)
  42 {
  43   // TODO: Once we abandon b2g18, we can switch this to use the
  44   // WakeLockInformation constructor, which is better because it doesn't let us
  45   // forget to assign a param.  For now we have to do it this way, because
  46   // b2g18 doesn't have the nsTArray <--> InfallibleTArray conversion (bug
  47   // 819791).
  48
  49   WakeLockInformation info;
  50   info.topic() = aTopic;
  51   info.numLocks() = aLockCount.numLocks;
  52   info.numHidden() = aLockCount.numHidden;
  53   info.lockingProcesses().AppendElements(aLockCount.processes);
  54   return info;
  55 }
  56
  57 PLDHashOperator
  58 CountWakeLocks(const uint64_t& aKey, LockCount aCount, void* aUserArg)
  59 {
  60   MOZ_ASSERT(aUserArg);
  61
  62   LockCount* totalCount = static_cast<LockCount*>(aUserArg);
  63   totalCount->numLocks += aCount.numLocks;
  64   totalCount->numHidden += aCount.numHidden;
  65
  66   // This is linear in the number of processes, but that should be small.
  67   if (!totalCount->processes.Contains(aKey)) {
  68     totalCount->processes.AppendElement(aKey);
  69   }
  70
  71   return PL_DHASH_NEXT;
  72 }
  73
  74 static PLDHashOperator
  75 RemoveChildFromList(const nsAString& aKey, nsAutoPtr<ProcessLockTable>& aTable,
  76                     void* aUserArg)
  77 {
  78   MOZ_ASSERT(aUserArg);
  79
  80   PLDHashOperator op = PL_DHASH_NEXT;
  81   uint64_t childID = *static_cast<uint64_t*>(aUserArg);
  82   if (aTable->Get(childID, nullptr)) {
  83     aTable->Remove(childID);
  84
  85     LockCount totalCount;
  86     aTable->EnumerateRead(CountWakeLocks, &totalCount);
  87     if (!totalCount.numLocks) {
  88       op = PL_DHASH_REMOVE;
  89     }
  90
  91     if (sActiveListeners) {
  92       NotifyWakeLockChange(WakeLockInfoFromLockCount(aKey, totalCount));
  93     }
  94   }
  95
  96   return op;
  97 }
  98
  99 class ClearHashtableOnShutdown MOZ_FINAL : public nsIObserver {
 100 public:
 101   NS_DECL_ISUPPORTS
 102   NS_DECL_NSIOBSERVER
 103 };
 104
 105 NS_IMPL_ISUPPORTS(ClearHashtableOnShutdown, nsIObserver)
 106
 107 NS_IMETHODIMP
 108 ClearHashtableOnShutdown::Observe(nsISupports* aSubject, const char* aTopic, const char16_t* data)
 109 {
 110   MOZ_ASSERT(!strcmp(aTopic, "xpcom-shutdown"));
 111
 112   sIsShuttingDown = true;
 113   sLockTable = nullptr;
 114
 115   return NS_OK;
 116 }
 117
 118 class CleanupOnContentShutdown MOZ_FINAL : public nsIObserver {
 119 public:
 120   NS_DECL_ISUPPORTS
 121   NS_DECL_NSIOBSERVER
 122 };
 123
 124 NS_IMPL_ISUPPORTS(CleanupOnContentShutdown, nsIObserver)
 125
 126 NS_IMETHODIMP
 127 CleanupOnContentShutdown::Observe(nsISupports* aSubject, const char* aTopic, const char16_t* data)
 128 {
 129   MOZ_ASSERT(!strcmp(aTopic, "ipc:content-shutdown"));
 130
 131   if (sIsShuttingDown) {
 132     return NS_OK;
 133   }
 134
 135   nsCOMPtr<nsIPropertyBag2> props = do_QueryInterface(aSubject);
 136   if (!props) {
 137     NS_WARNING("ipc:content-shutdown message without property bag as subject");
 138     return NS_OK;
 139   }
 140
 141   uint64_t childID = 0;
 142   nsresult rv = props->GetPropertyAsUint64(NS_LITERAL_STRING("childID"),
 143                                            &childID);
 144   if (NS_SUCCEEDED(rv)) {
 145     sLockTable->Enumerate(RemoveChildFromList, &childID);
 146   } else {
 147     NS_WARNING("ipc:content-shutdown message without childID property");
 148   }
 149   return NS_OK;
 150 }
 151
 152 void
 153 Init()
 154 {
 155   sLockTable = new LockTable();
 156   sInitialized = true;
 157
 158   nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
 159   if (obs) {
 160     obs->AddObserver(new ClearHashtableOnShutdown(), "xpcom-shutdown", false);
 161     obs->AddObserver(new CleanupOnContentShutdown(), "ipc:content-shutdown", false);
 162   }
 163 }
 164
 165 } // anonymous namespace
 166
 167 namespace mozilla {
 168
 169 namespace hal {
 170
 171 WakeLockState
 172 ComputeWakeLockState(int aNumLocks, int aNumHidden)
 173 {
 174   if (aNumLocks == 0) {
 175     return WAKE_LOCK_STATE_UNLOCKED;
 176   } else if (aNumLocks == aNumHidden) {
 177     return WAKE_LOCK_STATE_HIDDEN;
 178   } else {
 179     return WAKE_LOCK_STATE_VISIBLE;
 180   }
 181 }
 182
 183 } // namespace hal
 184
 185 namespace hal_impl {
 186
 187 void
 188 EnableWakeLockNotifications()
 189 {
 190   sActiveListeners++;
 191 }
 192
 193 void
 194 DisableWakeLockNotifications()
 195 {
 196   sActiveListeners--;
 197 }
 198
 199 void
 200 ModifyWakeLock(const nsAString& aTopic,
 201                hal::WakeLockControl aLockAdjust,
 202                hal::WakeLockControl aHiddenAdjust,
 203                uint64_t aProcessID)
 204 {
 205   MOZ_ASSERT(NS_IsMainThread());
 206   MOZ_ASSERT(aProcessID != CONTENT_PROCESS_ID_UNKNOWN);
 207
 208   if (sIsShuttingDown) {
 209     return;
 210   }
 211   if (!sInitialized) {
 212     Init();
 213   }
 214
 215   ProcessLockTable* table = sLockTable->Get(aTopic);
 216   LockCount processCount;
 217   LockCount totalCount;
 218   if (!table) {
 219     table = new ProcessLockTable();
 220     sLockTable->Put(aTopic, table);
 221   } else {
 222     table->Get(aProcessID, &processCount);
 223     table->EnumerateRead(CountWakeLocks, &totalCount);
 224   }
 225
 226   MOZ_ASSERT(processCount.numLocks >= processCount.numHidden);
 227   MOZ_ASSERT(aLockAdjust >= 0 || processCount.numLocks > 0);
 228   MOZ_ASSERT(aHiddenAdjust >= 0 || processCount.numHidden > 0);
 229   MOZ_ASSERT(totalCount.numLocks >= totalCount.numHidden);
 230   MOZ_ASSERT(aLockAdjust >= 0 || totalCount.numLocks > 0);
 231   MOZ_ASSERT(aHiddenAdjust >= 0 || totalCount.numHidden > 0);
 232
 233   WakeLockState oldState = ComputeWakeLockState(totalCount.numLocks, totalCount.numHidden);
 234   bool processWasLocked = processCount.numLocks > 0;
 235
 236   processCount.numLocks += aLockAdjust;
 237   processCount.numHidden += aHiddenAdjust;
 238
 239   totalCount.numLocks += aLockAdjust;
 240   totalCount.numHidden += aHiddenAdjust;
 241
 242   if (processCount.numLocks) {
 243     table->Put(aProcessID, processCount);
 244   } else {
 245     table->Remove(aProcessID);
 246   }
 247   if (!totalCount.numLocks) {
 248     sLockTable->Remove(aTopic);
 249   }
 250
 251   if (sActiveListeners &&
 252       (oldState != ComputeWakeLockState(totalCount.numLocks,
 253                                         totalCount.numHidden) ||
 254        processWasLocked != (processCount.numLocks > 0))) {
 255
 256     WakeLockInformation info;
 257     hal::GetWakeLockInfo(aTopic, &info);
 258     NotifyWakeLockChange(info);
 259   }
 260 }
 261
 262 void
 263 GetWakeLockInfo(const nsAString& aTopic, WakeLockInformation* aWakeLockInfo)
 264 {
 265   if (sIsShuttingDown) {
 266     NS_WARNING("You don't want to get wake lock information during xpcom-shutdown!");
 267     *aWakeLockInfo = WakeLockInformation();
 268     return;
 269   }
 270   if (!sInitialized) {
 271     Init();
 272   }
 273
 274   ProcessLockTable* table = sLockTable->Get(aTopic);
 275   if (!table) {
 276     *aWakeLockInfo = WakeLockInfoFromLockCount(aTopic, LockCount());
 277     return;
 278   }
 279   LockCount totalCount;
 280   table->EnumerateRead(CountWakeLocks, &totalCount);
 281   *aWakeLockInfo = WakeLockInfoFromLockCount(aTopic, totalCount);
 282 }
 283
 284 } // hal_impl
 285 } // mozilla