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Bug 1349388, part 3 - Provide AutoReferenceLimiter with a default maximum reference chain length. r=longsonr

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This commit is contained in:
Jonathan Watt 2017-02-16 11:18:33 +00:00
parent 6f850d0f40
commit 618c7360e8
2 changed files with 21 additions and 17 deletions
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4
layout/svg/AutoReferenceLimiter.h
View File

@ -63,11 +63,13 @@ namespace mozilla {
*/
class MOZ_RAII AutoReferenceLimiter
{
static const int16_t sDefaultMaxChainLength = 10; // arbitrary number
public:
static const int16_t notReferencing = -2;
AutoReferenceLimiter(nsIFrame* aFrame, int16_t* aRefCounter,
int16_t aMaxReferenceCount
int16_t aMaxReferenceCount = sDefaultMaxChainLength
MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;

34
layout/svg/nsSVGClipPathFrame.cpp
View File

@ -21,9 +21,6 @@ using namespace mozilla::dom;
using namespace mozilla::gfx;
using namespace mozilla::image;
// Arbitrary number
#define MAX_SVG_CLIP_PATH_REFERENCE_CHAIN_LENGTH int16_t(512)
//----------------------------------------------------------------------
// Implementation
@ -129,12 +126,13 @@ nsSVGClipPathFrame::PaintClipMask(gfxContext& aMaskContext,
SourceSurface* aExtraMask,
const Matrix& aExtraMasksTransform)
{
// A clipPath can reference another clipPath. We re-enter this method for
// each clipPath in a reference chain, so here we limit chain length:
static int16_t sRefChainLengthCounter = AutoReferenceLimiter::notReferencing;
AutoReferenceLimiter
refChainLengthLimiter(this, &sRefChainLengthCounter,
MAX_SVG_CLIP_PATH_REFERENCE_CHAIN_LENGTH);
// A clipPath can reference another clipPath, creating a chain of clipPaths
// that must all be applied. We re-enter this method for each clipPath in a
// chain, so here we limit the chain length by limiting the number of
// re-entries:
AutoReferenceLimiter refChainLengthLimiter(this, &sRefChainLengthCounter);
if (!refChainLengthLimiter.Reference()) {
return DrawResult::SUCCESS; // Reference chain is too long!
}
@ -298,12 +296,14 @@ bool
nsSVGClipPathFrame::PointIsInsideClipPath(nsIFrame* aClippedFrame,
const gfxPoint &aPoint)
{
// A clipPath can reference another clipPath. We re-enter this method for
// each clipPath in a reference chain, so here we limit chain length:
static int16_t sRefChainLengthCounter = AutoReferenceLimiter::notReferencing;
// A clipPath can reference another clipPath, creating a chain of clipPaths
// that must all be applied. We re-enter this method for each clipPath in a
// chain, so here we limit the chain length by limiting the number of
// re-entries:
AutoReferenceLimiter
refChainLengthLimiter(this, &sRefChainLengthCounter,
MAX_SVG_CLIP_PATH_REFERENCE_CHAIN_LENGTH);
refChainLengthLimiter(this, &sRefChainLengthCounter);
if (!refChainLengthLimiter.Reference()) {
return false; // Reference chain is too long!
}
@ -393,12 +393,14 @@ nsSVGClipPathFrame::IsTrivial(nsSVGDisplayableFrame **aSingleChild)
bool
nsSVGClipPathFrame::IsValid()
{
// A clipPath can reference another clipPath. We re-enter this method for
// each clipPath in a reference chain, so here we limit chain length:
static int16_t sRefChainLengthCounter = AutoReferenceLimiter::notReferencing;
// A clipPath can reference another clipPath, creating a chain of clipPaths
// that must all be applied. We re-enter this method for each clipPath in a
// chain, so here we limit the chain length by limiting the number of
// re-entries:
AutoReferenceLimiter
refChainLengthLimiter(this, &sRefChainLengthCounter,
MAX_SVG_CLIP_PATH_REFERENCE_CHAIN_LENGTH);
refChainLengthLimiter(this, &sRefChainLengthCounter);
if (!refChainLengthLimiter.Reference()) {
return false; // Reference chain is too long!
}