hal/HalWakeLock.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 "Hal.h"
   8 #include "base/process_util.h"
   9 #include "mozilla/FOGIPC.h"
  10 #include "mozilla/HalWakeLock.h"
  11 #include "mozilla/Services.h"
  12 #include "mozilla/StaticPtr.h"
  13 #include "nsClassHashtable.h"
  14 #include "nsTHashMap.h"
  15 #include "nsHashKeys.h"
  16 #include "nsIPropertyBag2.h"
  17 #include "nsIObserver.h"
  18 #include "nsIObserverService.h"
  19
  20 using namespace mozilla;
  21 using namespace mozilla::hal;
  22
  23 namespace {
  24
  25 struct LockCount {
  26   LockCount() : numLocks(0), numHidden(0) {}
  27   uint32_t numLocks;
  28   uint32_t numHidden;
  29   CopyableTArray<uint64_t> processes;
  30 };
  31
  32 typedef nsTHashMap<nsUint64HashKey, LockCount> ProcessLockTable;
  33 typedef nsClassHashtable<nsStringHashKey, ProcessLockTable> LockTable;
  34
  35 int sActiveListeners = 0;
  36 StaticAutoPtr<LockTable> sLockTable;
  37 bool sIsShuttingDown = false;
  38
  39 WakeLockInformation WakeLockInfoFromLockCount(const nsAString& aTopic,
  40                                               const LockCount& aLockCount) {
  41   nsString topic(aTopic);
  42   WakeLockInformation info(topic, aLockCount.numLocks, aLockCount.numHidden,
  43                            aLockCount.processes);
  44
  45   return info;
  46 }
  47
  48 static void CountWakeLocks(ProcessLockTable* aTable, LockCount* aTotalCount) {
  49   for (auto iter = aTable->Iter(); !iter.Done(); iter.Next()) {
  50     const uint64_t& key = iter.Key();
  51     LockCount count = iter.UserData();
  52
  53     aTotalCount->numLocks += count.numLocks;
  54     aTotalCount->numHidden += count.numHidden;
  55
  56     // This is linear in the number of processes, but that should be small.
  57     if (!aTotalCount->processes.Contains(key)) {
  58       aTotalCount->processes.AppendElement(key);
  59     }
  60   }
  61 }
  62
  63 class ClearHashtableOnShutdown final : public nsIObserver {
  64   ~ClearHashtableOnShutdown() {}
  65
  66  public:
  67   NS_DECL_ISUPPORTS
  68   NS_DECL_NSIOBSERVER
  69 };
  70
  71 NS_IMPL_ISUPPORTS(ClearHashtableOnShutdown, nsIObserver)
  72
  73 NS_IMETHODIMP
  74 ClearHashtableOnShutdown::Observe(nsISupports* aSubject, const char* aTopic,
  75                                   const char16_t* data) {
  76   MOZ_ASSERT(!strcmp(aTopic, "xpcom-shutdown"));
  77
  78   sIsShuttingDown = true;
  79   sLockTable = nullptr;
  80
  81   return NS_OK;
  82 }
  83
  84 class CleanupOnContentShutdown final : public nsIObserver {
  85   ~CleanupOnContentShutdown() {}
  86
  87  public:
  88   NS_DECL_ISUPPORTS
  89   NS_DECL_NSIOBSERVER
  90 };
  91
  92 NS_IMPL_ISUPPORTS(CleanupOnContentShutdown, nsIObserver)
  93
  94 NS_IMETHODIMP
  95 CleanupOnContentShutdown::Observe(nsISupports* aSubject, const char* aTopic,
  96                                   const char16_t* data) {
  97   MOZ_ASSERT(!strcmp(aTopic, "ipc:content-shutdown"));
  98
  99   if (sIsShuttingDown) {
 100     return NS_OK;
 101   }
 102
 103   nsCOMPtr<nsIPropertyBag2> props = do_QueryInterface(aSubject);
 104   if (!props) {
 105     NS_WARNING("ipc:content-shutdown message without property bag as subject");
 106     return NS_OK;
 107   }
 108
 109   uint64_t childID = 0;
 110   nsresult rv = props->GetPropertyAsUint64(u"childID"_ns, &childID);
 111   if (NS_SUCCEEDED(rv)) {
 112     for (auto iter = sLockTable->Iter(); !iter.Done(); iter.Next()) {
 113       auto table = iter.UserData();
 114
 115       if (table->Get(childID, nullptr)) {
 116         table->Remove(childID);
 117
 118         LockCount totalCount;
 119         CountWakeLocks(table, &totalCount);
 120
 121         if (sActiveListeners) {
 122           NotifyWakeLockChange(
 123               WakeLockInfoFromLockCount(iter.Key(), totalCount));
 124         }
 125
 126         if (totalCount.numLocks == 0) {
 127           iter.Remove();
 128         }
 129       }
 130     }
 131   } else {
 132     NS_WARNING("ipc:content-shutdown message without childID property");
 133   }
 134   return NS_OK;
 135 }
 136
 137 }  // namespace
 138
 139 namespace mozilla {
 140
 141 namespace hal {
 142
 143 void WakeLockInit() {
 144   sLockTable = new LockTable();
 145
 146   nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
 147   if (obs) {
 148     obs->AddObserver(new ClearHashtableOnShutdown(), "xpcom-shutdown", false);
 149     obs->AddObserver(new CleanupOnContentShutdown(), "ipc:content-shutdown",
 150                      false);
 151   }
 152 }
 153
 154 WakeLockState ComputeWakeLockState(int aNumLocks, int aNumHidden) {
 155   if (aNumLocks == 0) {
 156     return WAKE_LOCK_STATE_UNLOCKED;
 157   } else if (aNumLocks == aNumHidden) {
 158     return WAKE_LOCK_STATE_HIDDEN;
 159   } else {
 160     return WAKE_LOCK_STATE_VISIBLE;
 161   }
 162 }
 163
 164 }  // namespace hal
 165
 166 namespace hal_impl {
 167
 168 void EnableWakeLockNotifications() { sActiveListeners++; }
 169
 170 void DisableWakeLockNotifications() { sActiveListeners--; }
 171
 172 void ModifyWakeLock(const nsAString& aTopic, hal::WakeLockControl aLockAdjust,
 173                     hal::WakeLockControl aHiddenAdjust, uint64_t aProcessID) {
 174   MOZ_ASSERT(NS_IsMainThread());
 175   MOZ_ASSERT(aProcessID != CONTENT_PROCESS_ID_UNKNOWN);
 176
 177   if (sIsShuttingDown) {
 178     return;
 179   }
 180
 181   LockCount processCount;
 182   LockCount totalCount;
 183   ProcessLockTable* const table =
 184       sLockTable->WithEntryHandle(aTopic, [&](auto&& entry) {
 185         if (!entry) {
 186           entry.Insert(MakeUnique<ProcessLockTable>());
 187         } else {
 188           Unused << entry.Data()->Get(aProcessID, &processCount);
 189           CountWakeLocks(entry->get(), &totalCount);
 190         }
 191         return entry->get();
 192       });
 193
 194   MOZ_ASSERT(processCount.numLocks >= processCount.numHidden);
 195   MOZ_ASSERT(aLockAdjust >= 0 || processCount.numLocks > 0);
 196   MOZ_ASSERT(aHiddenAdjust >= 0 || processCount.numHidden > 0);
 197   MOZ_ASSERT(totalCount.numLocks >= totalCount.numHidden);
 198   MOZ_ASSERT(aLockAdjust >= 0 || totalCount.numLocks > 0);
 199   MOZ_ASSERT(aHiddenAdjust >= 0 || totalCount.numHidden > 0);
 200
 201   WakeLockState oldState =
 202       ComputeWakeLockState(totalCount.numLocks, totalCount.numHidden);
 203
 204   if (ComputeWakeLockState(totalCount.numLocks + aLockAdjust,
 205                            totalCount.numHidden + aHiddenAdjust) != oldState &&
 206       (aTopic.Equals(u"video-playing"_ns) ||
 207        aTopic.Equals(u"audio-playing"_ns))) {
 208     glean::RecordPowerMetrics();
 209   }
 210
 211   bool processWasLocked = processCount.numLocks > 0;
 212
 213   processCount.numLocks += aLockAdjust;
 214   processCount.numHidden += aHiddenAdjust;
 215
 216   totalCount.numLocks += aLockAdjust;
 217   totalCount.numHidden += aHiddenAdjust;
 218
 219   if (processCount.numLocks) {
 220     table->InsertOrUpdate(aProcessID, processCount);
 221   } else {
 222     table->Remove(aProcessID);
 223   }
 224   if (!totalCount.numLocks) {
 225     sLockTable->Remove(aTopic);
 226   }
 227
 228   if (sActiveListeners &&
 229       (oldState !=
 230            ComputeWakeLockState(totalCount.numLocks, totalCount.numHidden) ||
 231        processWasLocked != (processCount.numLocks > 0))) {
 232     WakeLockInformation info;
 233     hal::GetWakeLockInfo(aTopic, &info);
 234     NotifyWakeLockChange(info);
 235   }
 236 }
 237
 238 void GetWakeLockInfo(const nsAString& aTopic,
 239                      WakeLockInformation* aWakeLockInfo) {
 240   if (sIsShuttingDown) {
 241     NS_WARNING(
 242         "You don't want to get wake lock information during xpcom-shutdown!");
 243     *aWakeLockInfo = WakeLockInformation();
 244     return;
 245   }
 246
 247   if (!sLockTable) {
 248     // This can happen during some gtests.
 249     NS_WARNING("Attempting to get wake lock information before initialization");
 250     *aWakeLockInfo = WakeLockInformation();
 251     return;
 252   }
 253
 254   ProcessLockTable* table = sLockTable->Get(aTopic);
 255   if (!table) {
 256     *aWakeLockInfo = WakeLockInfoFromLockCount(aTopic, LockCount());
 257     return;
 258   }
 259   LockCount totalCount;
 260   CountWakeLocks(table, &totalCount);
 261   *aWakeLockInfo = WakeLockInfoFromLockCount(aTopic, totalCount);
 262 }
 263
 264 }  // namespace hal_impl
 265 }  // namespace mozilla