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/* 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 "nsVolumeMountLock.h"
#include "mozilla/dom/ContentChild.h"
#include "mozilla/Services.h"
#include "nsIObserverService.h"
#include "nsIPowerManagerService.h"
#include "nsIVolume.h"
#include "nsIVolumeService.h"
#include "nsString.h"
#include "nsXULAppAPI.h"
#undef VOLUME_MANAGER_LOG_TAG
#define VOLUME_MANAGER_LOG_TAG "nsVolumeMountLock"
#include "VolumeManagerLog.h"
#include "nsServiceManagerUtils.h"
#include "mozilla/dom/power/PowerManagerService.h"
using namespace mozilla::dom;
using namespace mozilla::services;
namespace mozilla {
namespace system {
NS_IMPL_ISUPPORTS(nsVolumeMountLock, nsIVolumeMountLock,
nsIObserver, nsISupportsWeakReference)
// static
already_AddRefed<nsVolumeMountLock>
nsVolumeMountLock::Create(const nsAString& aVolumeName)
{
DBG("nsVolumeMountLock::Create called");
RefPtr<nsVolumeMountLock> mountLock = new nsVolumeMountLock(aVolumeName);
nsresult rv = mountLock->Init();
NS_ENSURE_SUCCESS(rv, nullptr);
return mountLock.forget();
}
nsVolumeMountLock::nsVolumeMountLock(const nsAString& aVolumeName)
: mVolumeName(aVolumeName),
mVolumeGeneration(-1),
mUnlocked(false)
{
}
//virtual
nsVolumeMountLock::~nsVolumeMountLock()
{
Unlock();
}
nsresult nsVolumeMountLock::Init()
{
LOG("nsVolumeMountLock created for '%s'",
NS_LossyConvertUTF16toASCII(mVolumeName).get());
// Add ourselves as an Observer. It's important that we use a weak
// reference here. If we used a strong reference, then that reference
// would prevent this object from being destructed.
nsCOMPtr<nsIObserverService> obs = GetObserverService();
obs->AddObserver(this, NS_VOLUME_STATE_CHANGED, true /*weak*/);
// Get the initial mountGeneration and grab a lock.
nsCOMPtr<nsIVolumeService> vs = do_GetService(NS_VOLUMESERVICE_CONTRACTID);
NS_ENSURE_TRUE(vs, NS_ERROR_FAILURE);
nsCOMPtr<nsIVolume> vol;
nsresult rv = vs->GetVolumeByName(mVolumeName, getter_AddRefs(vol));
if (NS_WARN_IF(NS_FAILED(rv))) {
return rv;
}
rv = vol->GetMountGeneration(&mVolumeGeneration);
NS_ENSURE_SUCCESS(rv, rv);
return Lock(vol);
}
NS_IMETHODIMP nsVolumeMountLock::Unlock()
{
LOG("nsVolumeMountLock released for '%s'",
NS_LossyConvertUTF16toASCII(mVolumeName).get());
mUnlocked = true;
mWakeLock = nullptr;
// While we don't really need to remove weak observers, we do so anyways
// since it will reduce the number of times Observe gets called.
nsCOMPtr<nsIObserverService> obs = GetObserverService();
obs->RemoveObserver(this, NS_VOLUME_STATE_CHANGED);
return NS_OK;
}
NS_IMETHODIMP nsVolumeMountLock::Observe(nsISupports* aSubject, const char* aTopic, const char16_t* aData)
{
if (strcmp(aTopic, NS_VOLUME_STATE_CHANGED) != 0) {
return NS_OK;
}
if (mUnlocked) {
// We're not locked anymore, so we don't need to look at the notifications.
return NS_OK;
}
nsCOMPtr<nsIVolume> vol = do_QueryInterface(aSubject);
if (!vol) {
return NS_OK;
}
nsString volName;
vol->GetName(volName);
if (!volName.Equals(mVolumeName)) {
return NS_OK;
}
int32_t state;
nsresult rv = vol->GetState(&state);
NS_ENSURE_SUCCESS(rv, rv);
if (state != nsIVolume::STATE_MOUNTED) {
mWakeLock = nullptr;
mVolumeGeneration = -1;
return NS_OK;
}
int32_t mountGeneration;
rv = vol->GetMountGeneration(&mountGeneration);
NS_ENSURE_SUCCESS(rv, rv);
DBG("nsVolumeMountLock::Observe mountGeneration = %d mVolumeGeneration = %d",
mountGeneration, mVolumeGeneration);
if (mVolumeGeneration == mountGeneration) {
return NS_OK;
}
// The generation changed, which means that any wakelock we may have
// been holding is now invalid. Grab a new wakelock for the new generation
// number.
mWakeLock = nullptr;
mVolumeGeneration = mountGeneration;
return Lock(vol);
}
nsresult
nsVolumeMountLock::Lock(nsIVolume* aVolume)
{
RefPtr<power::PowerManagerService> pmService =
power::PowerManagerService::GetInstance();
NS_ENSURE_TRUE(pmService, NS_ERROR_FAILURE);
nsString mountLockName;
aVolume->GetMountLockName(mountLockName);
ErrorResult err;
mWakeLock = pmService->NewWakeLock(mountLockName, nullptr, err);
if (err.Failed()) {
return err.StealNSResult();
}
LOG("nsVolumeMountLock acquired for '%s' gen %d",
NS_LossyConvertUTF16toASCII(mVolumeName).get(), mVolumeGeneration);
return NS_OK;
}
} // namespace system
} // namespace mozilla
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