gecko-dev/dom/base/ImageTracker.cpp
2017-06-18 17:07:54 +02:00

159 lines
3.9 KiB
C++

/* -*- 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/. */
/* table of images used in a document, for batch locking/unlocking and
* animating */
#include "ImageTracker.h"
namespace mozilla {
namespace dom {
ImageTracker::ImageTracker()
: mLocking(false)
, mAnimating(true)
{
}
ImageTracker::~ImageTracker()
{
SetLockingState(false);
}
nsresult
ImageTracker::Add(imgIRequest* aImage)
{
MOZ_ASSERT(aImage);
nsresult rv = NS_OK;
auto entry = mImages.LookupForAdd(aImage);
if (entry) {
// The image is already in the hashtable. Increment its count.
uint32_t oldCount = entry.Data();
MOZ_ASSERT(oldCount > 0, "Entry in the image tracker with count 0!");
entry.Data() = oldCount + 1;
} else {
// A new entry was inserted - set the count to 1.
entry.OrInsert([]() { return 1; });
// If we're locking images, lock this image too.
if (mLocking) {
rv = aImage->LockImage();
}
// If we're animating images, request that this image be animated too.
if (mAnimating) {
nsresult rv2 = aImage->IncrementAnimationConsumers();
rv = NS_SUCCEEDED(rv) ? rv2 : rv;
}
}
return rv;
}
nsresult
ImageTracker::Remove(imgIRequest* aImage, uint32_t aFlags)
{
NS_ENSURE_ARG_POINTER(aImage);
// Get the old count. It should exist and be > 0.
if (auto entry = mImages.Lookup(aImage)) {
MOZ_ASSERT(entry.Data() > 0, "Entry in the image tracker with count 0!");
// If the count becomes zero, remove it from the tracker.
if (--entry.Data() == 0) {
entry.Remove();
} else {
return NS_OK;
}
} else {
MOZ_ASSERT_UNREACHABLE("Removing image that wasn't in the tracker!");
return NS_OK;
}
nsresult rv = NS_OK;
// Now that we're no longer tracking this image, unlock it if we'd
// previously locked it.
if (mLocking) {
rv = aImage->UnlockImage();
}
// If we're animating images, remove our request to animate this one.
if (mAnimating) {
nsresult rv2 = aImage->DecrementAnimationConsumers();
rv = NS_SUCCEEDED(rv) ? rv2 : rv;
}
if (aFlags & REQUEST_DISCARD) {
// Request that the image be discarded if nobody else holds a lock on it.
// Do this even if !mLocking, because even if we didn't just unlock
// this image, it might still be a candidate for discarding.
aImage->RequestDiscard();
}
return rv;
}
nsresult
ImageTracker::SetLockingState(bool aLocked)
{
if (XRE_IsContentProcess() &&
!Preferences::GetBool("image.mem.allow_locking_in_content_processes", true)) {
return NS_OK;
}
// If there's no change, there's nothing to do.
if (mLocking == aLocked)
return NS_OK;
// Otherwise, iterate over our images and perform the appropriate action.
for (auto iter = mImages.Iter(); !iter.Done(); iter.Next()) {
imgIRequest* image = iter.Key();
if (aLocked) {
image->LockImage();
} else {
image->UnlockImage();
}
}
// Update state.
mLocking = aLocked;
return NS_OK;
}
void
ImageTracker::SetAnimatingState(bool aAnimating)
{
// If there's no change, there's nothing to do.
if (mAnimating == aAnimating)
return;
// Otherwise, iterate over our images and perform the appropriate action.
for (auto iter = mImages.Iter(); !iter.Done(); iter.Next()) {
imgIRequest* image = iter.Key();
if (aAnimating) {
image->IncrementAnimationConsumers();
} else {
image->DecrementAnimationConsumers();
}
}
// Update state.
mAnimating = aAnimating;
}
void
ImageTracker::RequestDiscardAll()
{
for (auto iter = mImages.Iter(); !iter.Done(); iter.Next()) {
iter.Key()->RequestDiscard();
}
}
} // namespace dom
} // namespace mozilla