1 files changed, 265 insertions, 0 deletions
diff --git a/hal/HalWakeLock.cpp b/hal/HalWakeLock.cpp
new file mode 100644
index 0000000000..918f4b2da6
--- /dev/null
+++ b/hal/HalWakeLock.cpp
@@ -0,0 +1,265 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Hal.h"
+#include "base/process_util.h"
+#include "mozilla/FOGIPC.h"
+#include "mozilla/HalWakeLock.h"
+#include "mozilla/Services.h"
+#include "mozilla/StaticPtr.h"
+#include "nsClassHashtable.h"
+#include "nsTHashMap.h"
+#include "nsHashKeys.h"
+#include "nsIPropertyBag2.h"
+#include "nsIObserver.h"
+#include "nsIObserverService.h"
+
+using namespace mozilla;
+using namespace mozilla::hal;
+
+namespace {
+
+struct LockCount {
+  LockCount() : numLocks(0), numHidden(0) {}
+  uint32_t numLocks;
+  uint32_t numHidden;
+  CopyableTArray<uint64_t> processes;
+};
+
+typedef nsTHashMap<nsUint64HashKey, LockCount> ProcessLockTable;
+typedef nsClassHashtable<nsStringHashKey, ProcessLockTable> LockTable;
+
+int sActiveListeners = 0;
+StaticAutoPtr<LockTable> sLockTable;
+bool sIsShuttingDown = false;
+
+WakeLockInformation WakeLockInfoFromLockCount(const nsAString& aTopic,
+                                              const LockCount& aLockCount) {
+  nsString topic(aTopic);
+  WakeLockInformation info(topic, aLockCount.numLocks, aLockCount.numHidden,
+                           aLockCount.processes);
+
+  return info;
+}
+
+static void CountWakeLocks(ProcessLockTable* aTable, LockCount* aTotalCount) {
+  for (auto iter = aTable->Iter(); !iter.Done(); iter.Next()) {
+    const uint64_t& key = iter.Key();
+    LockCount count = iter.UserData();
+
+    aTotalCount->numLocks += count.numLocks;
+    aTotalCount->numHidden += count.numHidden;
+
+    // This is linear in the number of processes, but that should be small.
+    if (!aTotalCount->processes.Contains(key)) {
+      aTotalCount->processes.AppendElement(key);
+    }
+  }
+}
+
+class ClearHashtableOnShutdown final : public nsIObserver {
+  ~ClearHashtableOnShutdown() {}
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+};
+
+NS_IMPL_ISUPPORTS(ClearHashtableOnShutdown, nsIObserver)
+
+NS_IMETHODIMP
+ClearHashtableOnShutdown::Observe(nsISupports* aSubject, const char* aTopic,
+                                  const char16_t* data) {
+  MOZ_ASSERT(!strcmp(aTopic, "xpcom-shutdown"));
+
+  sIsShuttingDown = true;
+  sLockTable = nullptr;
+
+  return NS_OK;
+}
+
+class CleanupOnContentShutdown final : public nsIObserver {
+  ~CleanupOnContentShutdown() {}
+
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+};
+
+NS_IMPL_ISUPPORTS(CleanupOnContentShutdown, nsIObserver)
+
+NS_IMETHODIMP
+CleanupOnContentShutdown::Observe(nsISupports* aSubject, const char* aTopic,
+                                  const char16_t* data) {
+  MOZ_ASSERT(!strcmp(aTopic, "ipc:content-shutdown"));
+
+  if (sIsShuttingDown) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIPropertyBag2> props = do_QueryInterface(aSubject);
+  if (!props) {
+    NS_WARNING("ipc:content-shutdown message without property bag as subject");
+    return NS_OK;
+  }
+
+  uint64_t childID = 0;
+  nsresult rv = props->GetPropertyAsUint64(u"childID"_ns, &childID);
+  if (NS_SUCCEEDED(rv)) {
+    for (auto iter = sLockTable->Iter(); !iter.Done(); iter.Next()) {
+      auto table = iter.UserData();
+
+      if (table->Get(childID, nullptr)) {
+        table->Remove(childID);
+
+        LockCount totalCount;
+        CountWakeLocks(table, &totalCount);
+
+        if (sActiveListeners) {
+          NotifyWakeLockChange(
+              WakeLockInfoFromLockCount(iter.Key(), totalCount));
+        }
+
+        if (totalCount.numLocks == 0) {
+          iter.Remove();
+        }
+      }
+    }
+  } else {
+    NS_WARNING("ipc:content-shutdown message without childID property");
+  }
+  return NS_OK;
+}
+
+}  // namespace
+
+namespace mozilla {
+
+namespace hal {
+
+void WakeLockInit() {
+  sLockTable = new LockTable();
+
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->AddObserver(new ClearHashtableOnShutdown(), "xpcom-shutdown", false);
+    obs->AddObserver(new CleanupOnContentShutdown(), "ipc:content-shutdown",
+                     false);
+  }
+}
+
+WakeLockState ComputeWakeLockState(int aNumLocks, int aNumHidden) {
+  if (aNumLocks == 0) {
+    return WAKE_LOCK_STATE_UNLOCKED;
+  } else if (aNumLocks == aNumHidden) {
+    return WAKE_LOCK_STATE_HIDDEN;
+  } else {
+    return WAKE_LOCK_STATE_VISIBLE;
+  }
+}
+
+}  // namespace hal
+
+namespace hal_impl {
+
+void EnableWakeLockNotifications() { sActiveListeners++; }
+
+void DisableWakeLockNotifications() { sActiveListeners--; }
+
+void ModifyWakeLock(const nsAString& aTopic, hal::WakeLockControl aLockAdjust,
+                    hal::WakeLockControl aHiddenAdjust, uint64_t aProcessID) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(aProcessID != CONTENT_PROCESS_ID_UNKNOWN);
+
+  if (sIsShuttingDown) {
+    return;
+  }
+
+  LockCount processCount;
+  LockCount totalCount;
+  ProcessLockTable* const table =
+      sLockTable->WithEntryHandle(aTopic, [&](auto&& entry) {
+        if (!entry) {
+          entry.Insert(MakeUnique<ProcessLockTable>());
+        } else {
+          Unused << entry.Data()->Get(aProcessID, &processCount);
+          CountWakeLocks(entry->get(), &totalCount);
+        }
+        return entry->get();
+      });
+
+  MOZ_ASSERT(processCount.numLocks >= processCount.numHidden);
+  MOZ_ASSERT(aLockAdjust >= 0 || processCount.numLocks > 0);
+  MOZ_ASSERT(aHiddenAdjust >= 0 || processCount.numHidden > 0);
+  MOZ_ASSERT(totalCount.numLocks >= totalCount.numHidden);
+  MOZ_ASSERT(aLockAdjust >= 0 || totalCount.numLocks > 0);
+  MOZ_ASSERT(aHiddenAdjust >= 0 || totalCount.numHidden > 0);
+
+  WakeLockState oldState =
+      ComputeWakeLockState(totalCount.numLocks, totalCount.numHidden);
+
+  if (ComputeWakeLockState(totalCount.numLocks + aLockAdjust,
+                           totalCount.numHidden + aHiddenAdjust) != oldState &&
+      (aTopic.Equals(u"video-playing"_ns) ||
+       aTopic.Equals(u"audio-playing"_ns))) {
+    glean::RecordPowerMetrics();
+  }
+
+  bool processWasLocked = processCount.numLocks > 0;
+
+  processCount.numLocks += aLockAdjust;
+  processCount.numHidden += aHiddenAdjust;
+
+  totalCount.numLocks += aLockAdjust;
+  totalCount.numHidden += aHiddenAdjust;
+
+  if (processCount.numLocks) {
+    table->InsertOrUpdate(aProcessID, processCount);
+  } else {
+    table->Remove(aProcessID);
+  }
+  if (!totalCount.numLocks) {
+    sLockTable->Remove(aTopic);
+  }
+
+  if (sActiveListeners &&
+      (oldState !=
+           ComputeWakeLockState(totalCount.numLocks, totalCount.numHidden) ||
+       processWasLocked != (processCount.numLocks > 0))) {
+    WakeLockInformation info;
+    hal::GetWakeLockInfo(aTopic, &info);
+    NotifyWakeLockChange(info);
+  }
+}
+
+void GetWakeLockInfo(const nsAString& aTopic,
+                     WakeLockInformation* aWakeLockInfo) {
+  if (sIsShuttingDown) {
+    NS_WARNING(
+        "You don't want to get wake lock information during xpcom-shutdown!");
+    *aWakeLockInfo = WakeLockInformation();
+    return;
+  }
+
+  if (!sLockTable) {
+    // This can happen during some gtests.
+    NS_WARNING("Attempting to get wake lock information before initialization");
+    *aWakeLockInfo = WakeLockInformation();
+    return;
+  }
+
+  ProcessLockTable* table = sLockTable->Get(aTopic);
+  if (!table) {
+    *aWakeLockInfo = WakeLockInfoFromLockCount(aTopic, LockCount());
+    return;
+  }
+  LockCount totalCount;
+  CountWakeLocks(table, &totalCount);
+  *aWakeLockInfo = WakeLockInfoFromLockCount(aTopic, totalCount);
+}
+
+}  // namespace hal_impl
+}  // namespace mozilla