gecko-dev/gfx/thebes/gfxGradientCache.cpp
2017-07-03 16:19:58 -07:00

242 lines
7.0 KiB
C++

/* -*- Mode: C++; tab-width: 2; 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/gfx/2D.h"
#include "nsTArray.h"
#include "PLDHashTable.h"
#include "nsExpirationTracker.h"
#include "nsClassHashtable.h"
#include "mozilla/SystemGroup.h"
#include "mozilla/Telemetry.h"
#include "gfxGradientCache.h"
#include <time.h>
namespace mozilla {
namespace gfx {
using namespace mozilla;
struct GradientCacheKey : public PLDHashEntryHdr {
typedef const GradientCacheKey& KeyType;
typedef const GradientCacheKey* KeyTypePointer;
enum { ALLOW_MEMMOVE = true };
const nsTArray<GradientStop> mStops;
ExtendMode mExtend;
BackendType mBackendType;
GradientCacheKey(const nsTArray<GradientStop>& aStops, ExtendMode aExtend, BackendType aBackendType)
: mStops(aStops), mExtend(aExtend), mBackendType(aBackendType)
{ }
explicit GradientCacheKey(const GradientCacheKey* aOther)
: mStops(aOther->mStops), mExtend(aOther->mExtend), mBackendType(aOther->mBackendType)
{ }
union FloatUint32
{
float f;
uint32_t u;
};
static PLDHashNumber
HashKey(const KeyTypePointer aKey)
{
PLDHashNumber hash = 0;
FloatUint32 convert;
hash = AddToHash(hash, int(aKey->mBackendType));
hash = AddToHash(hash, int(aKey->mExtend));
for (uint32_t i = 0; i < aKey->mStops.Length(); i++) {
hash = AddToHash(hash, aKey->mStops[i].color.ToABGR());
// Use the float bits as hash, except for the cases of 0.0 and -0.0 which both map to 0
convert.f = aKey->mStops[i].offset;
hash = AddToHash(hash, convert.f ? convert.u : 0);
}
return hash;
}
bool KeyEquals(KeyTypePointer aKey) const
{
bool sameStops = true;
if (aKey->mStops.Length() != mStops.Length()) {
sameStops = false;
} else {
for (uint32_t i = 0; i < mStops.Length(); i++) {
if (mStops[i].color.ToABGR() != aKey->mStops[i].color.ToABGR() ||
mStops[i].offset != aKey->mStops[i].offset) {
sameStops = false;
break;
}
}
}
return sameStops &&
(aKey->mBackendType == mBackendType) &&
(aKey->mExtend == mExtend);
}
static KeyTypePointer KeyToPointer(KeyType aKey)
{
return &aKey;
}
};
/**
* This class is what is cached. It need to be allocated in an object separated
* to the cache entry to be able to be tracked by the nsExpirationTracker.
* */
struct GradientCacheData {
GradientCacheData(GradientStops* aStops, const GradientCacheKey& aKey)
: mStops(aStops),
mKey(aKey)
{}
GradientCacheData(const GradientCacheData& aOther)
: mStops(aOther.mStops),
mKey(aOther.mKey)
{ }
nsExpirationState *GetExpirationState() {
return &mExpirationState;
}
nsExpirationState mExpirationState;
const RefPtr<GradientStops> mStops;
GradientCacheKey mKey;
};
/**
* This class implements a cache with no maximum size, that retains the
* gfxPatterns used to draw the gradients.
*
* The key is the nsStyleGradient that defines the gradient, and the size of the
* gradient.
*
* The value is the gfxPattern, and whether or not we perform an optimization
* based on the actual gradient property.
*
* An entry stays in the cache as long as it is used often. As long as a cache
* entry is in the cache, all the references it has are guaranteed to be valid:
* the nsStyleRect for the key, the gfxPattern for the value.
*/
class GradientCache final : public nsExpirationTracker<GradientCacheData,4>
{
public:
GradientCache()
: nsExpirationTracker<GradientCacheData,4>(MAX_GENERATION_MS,
"GradientCache",
SystemGroup::EventTargetFor(TaskCategory::Other))
{
srand(time(nullptr));
mTimerPeriod = rand() % MAX_GENERATION_MS + 1;
Telemetry::Accumulate(Telemetry::GRADIENT_RETENTION_TIME, mTimerPeriod);
}
virtual void NotifyExpired(GradientCacheData* aObject)
{
// This will free the gfxPattern.
RemoveObject(aObject);
mHashEntries.Remove(aObject->mKey);
}
GradientCacheData* Lookup(const nsTArray<GradientStop>& aStops, ExtendMode aExtend, BackendType aBackendType)
{
GradientCacheData* gradient =
mHashEntries.Get(GradientCacheKey(aStops, aExtend, aBackendType));
if (gradient) {
MarkUsed(gradient);
}
return gradient;
}
// Returns true if we successfully register the gradient in the cache, false
// otherwise.
bool RegisterEntry(GradientCacheData* aValue)
{
nsresult rv = AddObject(aValue);
if (NS_FAILED(rv)) {
// We are OOM, and we cannot track this object. We don't want stall
// entries in the hash table (since the expiration tracker is responsible
// for removing the cache entries), so we avoid putting that entry in the
// table, which is a good things considering we are short on memory
// anyway, we probably don't want to retain things.
return false;
}
mHashEntries.Put(aValue->mKey, aValue);
return true;
}
protected:
uint32_t mTimerPeriod;
static const uint32_t MAX_GENERATION_MS = 10000;
/**
* FIXME use nsTHashtable to avoid duplicating the GradientCacheKey.
* https://bugzilla.mozilla.org/show_bug.cgi?id=761393#c47
*/
nsClassHashtable<GradientCacheKey, GradientCacheData> mHashEntries;
};
static GradientCache* gGradientCache = nullptr;
GradientStops *
gfxGradientCache::GetGradientStops(const DrawTarget *aDT, nsTArray<GradientStop>& aStops, ExtendMode aExtend)
{
if (!gGradientCache) {
gGradientCache = new GradientCache();
}
GradientCacheData* cached =
gGradientCache->Lookup(aStops, aExtend, aDT->GetBackendType());
if (cached && cached->mStops) {
if (!cached->mStops->IsValid()) {
gGradientCache->NotifyExpired(cached);
} else {
return cached->mStops;
}
}
return nullptr;
}
already_AddRefed<GradientStops>
gfxGradientCache::GetOrCreateGradientStops(const DrawTarget *aDT, nsTArray<GradientStop>& aStops, ExtendMode aExtend)
{
if (aDT->IsRecording()) {
return aDT->CreateGradientStops(aStops.Elements(), aStops.Length(), aExtend);
}
RefPtr<GradientStops> gs = GetGradientStops(aDT, aStops, aExtend);
if (!gs) {
gs = aDT->CreateGradientStops(aStops.Elements(), aStops.Length(), aExtend);
if (!gs) {
return nullptr;
}
GradientCacheData *cached =
new GradientCacheData(gs, GradientCacheKey(aStops, aExtend,
aDT->GetBackendType()));
if (!gGradientCache->RegisterEntry(cached)) {
delete cached;
}
}
return gs.forget();
}
void
gfxGradientCache::PurgeAllCaches()
{
if (gGradientCache) {
gGradientCache->AgeAllGenerations();
}
}
void
gfxGradientCache::Shutdown()
{
delete gGradientCache;
gGradientCache = nullptr;
}
} // namespace gfx
} // namespace mozilla