gecko-dev/hal/HalWakeLock.cpp
2012-07-15 11:13:15 -04:00

160 lines
3.5 KiB
C++

/* -*- Mode: C++; tab-width: 40; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "mozilla/Hal.h"
#include "mozilla/HalWakeLock.h"
#include "mozilla/Services.h"
#include "nsObserverService.h"
#include "nsDataHashtable.h"
#include "nsHashKeys.h"
using namespace mozilla::hal;
namespace mozilla {
namespace hal {
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;
}
}
} // hal
} // mozilla
namespace mozilla {
namespace hal_impl {
namespace {
struct LockCount {
PRUint32 numLocks;
PRUint32 numHidden;
};
}
static int sActiveChildren = 0;
static nsAutoPtr<nsDataHashtable<nsStringHashKey, LockCount> > sLockTable;
static bool sInitialized = false;
static bool sIsShuttingDown = false;
namespace {
class ClearHashtableOnShutdown MOZ_FINAL : public nsIObserver {
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
};
NS_IMPL_ISUPPORTS1(ClearHashtableOnShutdown, nsIObserver)
NS_IMETHODIMP
ClearHashtableOnShutdown::Observe(nsISupports* aSubject, const char* aTopic, const PRUnichar* data)
{
MOZ_ASSERT(!strcmp(aTopic, "xpcom-shutdown"));
sIsShuttingDown = true;
sLockTable = nsnull;
return NS_OK;
}
} // anonymous namespace
static void
Init()
{
sLockTable = new nsDataHashtable<nsStringHashKey, LockCount>();
sLockTable->Init();
sInitialized = true;
nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
if (obs) {
obs->AddObserver(new ClearHashtableOnShutdown(), "xpcom-shutdown", false);
}
}
void
EnableWakeLockNotifications()
{
sActiveChildren++;
}
void
DisableWakeLockNotifications()
{
sActiveChildren--;
}
void
ModifyWakeLock(const nsAString &aTopic,
hal::WakeLockControl aLockAdjust,
hal::WakeLockControl aHiddenAdjust)
{
if (sIsShuttingDown) {
return;
}
if (!sInitialized) {
Init();
}
LockCount count;
count.numLocks = 0;
count.numHidden = 0;
sLockTable->Get(aTopic, &count);
MOZ_ASSERT(count.numLocks >= count.numHidden);
MOZ_ASSERT(aLockAdjust >= 0 || count.numLocks > 0);
MOZ_ASSERT(aHiddenAdjust >= 0 || count.numHidden > 0);
WakeLockState oldState = ComputeWakeLockState(count.numLocks, count.numHidden);
count.numLocks += aLockAdjust;
count.numHidden += aHiddenAdjust;
MOZ_ASSERT(count.numLocks >= count.numHidden);
if (count.numLocks) {
sLockTable->Put(aTopic, count);
} else {
sLockTable->Remove(aTopic);
}
WakeLockState newState = ComputeWakeLockState(count.numLocks, count.numHidden);
if (sActiveChildren && oldState != newState) {
WakeLockInformation info;
info.numLocks() = count.numLocks;
info.numHidden() = count.numHidden;
info.topic() = aTopic;
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!");
return;
}
if (!sInitialized) {
Init();
}
LockCount count;
count.numLocks = 0;
count.numHidden = 0;
sLockTable->Get(aTopic, &count);
aWakeLockInfo->numLocks() = count.numLocks;
aWakeLockInfo->numHidden() = count.numHidden;
aWakeLockInfo->topic() = aTopic;
}
} // hal_impl
} // mozilla