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Diffstat (limited to 'image/SurfaceCache.cpp')
| -rw-r--r-- | image/SurfaceCache.cpp | 1974 |
1 files changed, 1974 insertions, 0 deletions
diff --git a/image/SurfaceCache.cpp b/image/SurfaceCache.cpp new file mode 100644 index 0000000000..5cfe7c086b --- /dev/null +++ b/image/SurfaceCache.cpp @@ -0,0 +1,1974 @@ +/* -*- 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/. */ + +/** + * SurfaceCache is a service for caching temporary surfaces in imagelib. + */ + +#include "SurfaceCache.h" + +#include <algorithm> +#include <utility> + +#include "ISurfaceProvider.h" +#include "Image.h" +#include "LookupResult.h" +#include "ShutdownTracker.h" +#include "gfx2DGlue.h" +#include "gfxPlatform.h" +#include "imgFrame.h" +#include "mozilla/AppShutdown.h" +#include "mozilla/Assertions.h" +#include "mozilla/Attributes.h" +#include "mozilla/CheckedInt.h" +#include "mozilla/DebugOnly.h" +#include "mozilla/Likely.h" +#include "mozilla/RefPtr.h" +#include "mozilla/StaticMutex.h" +#include "mozilla/StaticPrefs_image.h" +#include "mozilla/StaticPtr.h" + +#include "nsExpirationTracker.h" +#include "nsHashKeys.h" +#include "nsIMemoryReporter.h" +#include "nsRefPtrHashtable.h" +#include "nsSize.h" +#include "nsTArray.h" +#include "Orientation.h" +#include "prsystem.h" + +using std::max; +using std::min; + +namespace mozilla { + +using namespace gfx; + +namespace image { + +MOZ_DEFINE_MALLOC_SIZE_OF(SurfaceCacheMallocSizeOf) + +class CachedSurface; +class SurfaceCacheImpl; + +/////////////////////////////////////////////////////////////////////////////// +// Static Data +/////////////////////////////////////////////////////////////////////////////// + +// The single surface cache instance. +static StaticRefPtr<SurfaceCacheImpl> sInstance; + +// The mutex protecting the surface cache. +static StaticMutex sInstanceMutex MOZ_UNANNOTATED; + +/////////////////////////////////////////////////////////////////////////////// +// SurfaceCache Implementation +/////////////////////////////////////////////////////////////////////////////// + +/** + * Cost models the cost of storing a surface in the cache. Right now, this is + * simply an estimate of the size of the surface in bytes, but in the future it + * may be worth taking into account the cost of rematerializing the surface as + * well. + */ +typedef size_t Cost; + +static Cost ComputeCost(const IntSize& aSize, uint32_t aBytesPerPixel) { + MOZ_ASSERT(aBytesPerPixel == 1 || aBytesPerPixel == 4); + return aSize.width * aSize.height * aBytesPerPixel; +} + +/** + * Since we want to be able to make eviction decisions based on cost, we need to + * be able to look up the CachedSurface which has a certain cost as well as the + * cost associated with a certain CachedSurface. To make this possible, in data + * structures we actually store a CostEntry, which contains a weak pointer to + * its associated surface. + * + * To make usage of the weak pointer safe, SurfaceCacheImpl always calls + * StartTracking after a surface is stored in the cache and StopTracking before + * it is removed. + */ +class CostEntry { + public: + CostEntry(NotNull<CachedSurface*> aSurface, Cost aCost) + : mSurface(aSurface), mCost(aCost) {} + + NotNull<CachedSurface*> Surface() const { return mSurface; } + Cost GetCost() const { return mCost; } + + bool operator==(const CostEntry& aOther) const { + return mSurface == aOther.mSurface && mCost == aOther.mCost; + } + + bool operator<(const CostEntry& aOther) const { + return mCost < aOther.mCost || + (mCost == aOther.mCost && mSurface < aOther.mSurface); + } + + private: + NotNull<CachedSurface*> mSurface; + Cost mCost; +}; + +/** + * A CachedSurface associates a surface with a key that uniquely identifies that + * surface. + */ +class CachedSurface { + ~CachedSurface() {} + + public: + MOZ_DECLARE_REFCOUNTED_TYPENAME(CachedSurface) + NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CachedSurface) + + explicit CachedSurface(NotNull<ISurfaceProvider*> aProvider) + : mProvider(aProvider), mIsLocked(false) {} + + DrawableSurface GetDrawableSurface() const { + if (MOZ_UNLIKELY(IsPlaceholder())) { + MOZ_ASSERT_UNREACHABLE("Called GetDrawableSurface() on a placeholder"); + return DrawableSurface(); + } + + return mProvider->Surface(); + } + + DrawableSurface GetDrawableSurfaceEvenIfPlaceholder() const { + return mProvider->Surface(); + } + + void SetLocked(bool aLocked) { + if (IsPlaceholder()) { + return; // Can't lock a placeholder. + } + + // Update both our state and our provider's state. Some surface providers + // are permanently locked; maintaining our own locking state enables us to + // respect SetLocked() even when it's meaningless from the provider's + // perspective. + mIsLocked = aLocked; + mProvider->SetLocked(aLocked); + } + + bool IsLocked() const { + return !IsPlaceholder() && mIsLocked && mProvider->IsLocked(); + } + + void SetCannotSubstitute() { + mProvider->Availability().SetCannotSubstitute(); + } + bool CannotSubstitute() const { + return mProvider->Availability().CannotSubstitute(); + } + + bool IsPlaceholder() const { + return mProvider->Availability().IsPlaceholder(); + } + bool IsDecoded() const { return !IsPlaceholder() && mProvider->IsFinished(); } + + ImageKey GetImageKey() const { return mProvider->GetImageKey(); } + const SurfaceKey& GetSurfaceKey() const { return mProvider->GetSurfaceKey(); } + nsExpirationState* GetExpirationState() { return &mExpirationState; } + + CostEntry GetCostEntry() { + return image::CostEntry(WrapNotNull(this), mProvider->LogicalSizeInBytes()); + } + + size_t ShallowSizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const { + return aMallocSizeOf(this) + aMallocSizeOf(mProvider.get()); + } + + void InvalidateRecording() { mProvider->InvalidateRecording(); } + + // A helper type used by SurfaceCacheImpl::CollectSizeOfSurfaces. + struct MOZ_STACK_CLASS SurfaceMemoryReport { + SurfaceMemoryReport(nsTArray<SurfaceMemoryCounter>& aCounters, + MallocSizeOf aMallocSizeOf) + : mCounters(aCounters), mMallocSizeOf(aMallocSizeOf) {} + + void Add(NotNull<CachedSurface*> aCachedSurface, bool aIsFactor2) { + if (aCachedSurface->IsPlaceholder()) { + return; + } + + // Record the memory used by the ISurfaceProvider. This may not have a + // straightforward relationship to the size of the surface that + // DrawableRef() returns if the surface is generated dynamically. (i.e., + // for surfaces with PlaybackType::eAnimated.) + aCachedSurface->mProvider->AddSizeOfExcludingThis( + mMallocSizeOf, [&](ISurfaceProvider::AddSizeOfCbData& aMetadata) { + SurfaceMemoryCounter counter(aCachedSurface->GetSurfaceKey(), + aCachedSurface->IsLocked(), + aCachedSurface->CannotSubstitute(), + aIsFactor2, aMetadata.mFinished); + + counter.Values().SetDecodedHeap(aMetadata.mHeapBytes); + counter.Values().SetDecodedNonHeap(aMetadata.mNonHeapBytes); + counter.Values().SetDecodedUnknown(aMetadata.mUnknownBytes); + counter.Values().SetExternalHandles(aMetadata.mExternalHandles); + counter.Values().SetFrameIndex(aMetadata.mIndex); + counter.Values().SetExternalId(aMetadata.mExternalId); + counter.Values().SetSurfaceTypes(aMetadata.mTypes); + + mCounters.AppendElement(counter); + }); + } + + private: + nsTArray<SurfaceMemoryCounter>& mCounters; + MallocSizeOf mMallocSizeOf; + }; + + private: + nsExpirationState mExpirationState; + NotNull<RefPtr<ISurfaceProvider>> mProvider; + bool mIsLocked; +}; + +static int64_t AreaOfIntSize(const IntSize& aSize) { + return static_cast<int64_t>(aSize.width) * static_cast<int64_t>(aSize.height); +} + +/** + * An ImageSurfaceCache is a per-image surface cache. For correctness we must be + * able to remove all surfaces associated with an image when the image is + * destroyed or invalidated. Since this will happen frequently, it makes sense + * to make it cheap by storing the surfaces for each image separately. + * + * ImageSurfaceCache also keeps track of whether its associated image is locked + * or unlocked. + * + * The cache may also enter "factor of 2" mode which occurs when the number of + * surfaces in the cache exceeds the "image.cache.factor2.threshold-surfaces" + * pref plus the number of native sizes of the image. When in "factor of 2" + * mode, the cache will strongly favour sizes which are a factor of 2 of the + * largest native size. It accomplishes this by suggesting a factor of 2 size + * when lookups fail and substituting the nearest factor of 2 surface to the + * ideal size as the "best" available (as opposed to substitution but not + * found). This allows us to minimize memory consumption and CPU time spent + * decoding when a website requires many variants of the same surface. + */ +class ImageSurfaceCache { + ~ImageSurfaceCache() {} + + public: + explicit ImageSurfaceCache(const ImageKey aImageKey) + : mLocked(false), + mFactor2Mode(false), + mFactor2Pruned(false), + mIsVectorImage(aImageKey->GetType() == imgIContainer::TYPE_VECTOR) {} + + MOZ_DECLARE_REFCOUNTED_TYPENAME(ImageSurfaceCache) + NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ImageSurfaceCache) + + typedef nsRefPtrHashtable<nsGenericHashKey<SurfaceKey>, CachedSurface> + SurfaceTable; + + auto Values() const { return mSurfaces.Values(); } + uint32_t Count() const { return mSurfaces.Count(); } + bool IsEmpty() const { return mSurfaces.Count() == 0; } + + size_t ShallowSizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const { + size_t bytes = aMallocSizeOf(this) + + mSurfaces.ShallowSizeOfExcludingThis(aMallocSizeOf); + for (const auto& value : Values()) { + bytes += value->ShallowSizeOfIncludingThis(aMallocSizeOf); + } + return bytes; + } + + [[nodiscard]] bool Insert(NotNull<CachedSurface*> aSurface) { + MOZ_ASSERT(!mLocked || aSurface->IsPlaceholder() || aSurface->IsLocked(), + "Inserting an unlocked surface for a locked image"); + const auto& surfaceKey = aSurface->GetSurfaceKey(); + if (surfaceKey.Region()) { + // We don't allow substitutes for surfaces with regions, so we don't want + // to allow factor of 2 mode pruning to release these surfaces. + aSurface->SetCannotSubstitute(); + } + return mSurfaces.InsertOrUpdate(surfaceKey, RefPtr<CachedSurface>{aSurface}, + fallible); + } + + already_AddRefed<CachedSurface> Remove(NotNull<CachedSurface*> aSurface) { + MOZ_ASSERT(mSurfaces.GetWeak(aSurface->GetSurfaceKey()), + "Should not be removing a surface we don't have"); + + RefPtr<CachedSurface> surface; + mSurfaces.Remove(aSurface->GetSurfaceKey(), getter_AddRefs(surface)); + AfterMaybeRemove(); + return surface.forget(); + } + + already_AddRefed<CachedSurface> Lookup(const SurfaceKey& aSurfaceKey, + bool aForAccess) { + RefPtr<CachedSurface> surface; + mSurfaces.Get(aSurfaceKey, getter_AddRefs(surface)); + + if (aForAccess) { + if (surface) { + // We don't want to allow factor of 2 mode pruning to release surfaces + // for which the callers will accept no substitute. + surface->SetCannotSubstitute(); + } else if (!mFactor2Mode) { + // If no exact match is found, and this is for use rather than internal + // accounting (i.e. insert and removal), we know this will trigger a + // decode. Make sure we switch now to factor of 2 mode if necessary. + MaybeSetFactor2Mode(); + } + } + + return surface.forget(); + } + + /** + * @returns A tuple containing the best matching CachedSurface if available, + * a MatchType describing how the CachedSurface was selected, and + * an IntSize which is the size the caller should choose to decode + * at should it attempt to do so. + */ + std::tuple<already_AddRefed<CachedSurface>, MatchType, IntSize> + LookupBestMatch(const SurfaceKey& aIdealKey) { + // Try for an exact match first. + RefPtr<CachedSurface> exactMatch; + mSurfaces.Get(aIdealKey, getter_AddRefs(exactMatch)); + if (exactMatch) { + if (exactMatch->IsDecoded()) { + return std::make_tuple(exactMatch.forget(), MatchType::EXACT, + IntSize()); + } + } else if (aIdealKey.Region()) { + // We cannot substitute if we have a region. Allow it to create an exact + // match. + return std::make_tuple(exactMatch.forget(), MatchType::NOT_FOUND, + IntSize()); + } else if (!mFactor2Mode) { + // If no exact match is found, and we are not in factor of 2 mode, then + // we know that we will trigger a decode because at best we will provide + // a substitute. Make sure we switch now to factor of 2 mode if necessary. + MaybeSetFactor2Mode(); + } + + // Try for a best match second, if using compact. + IntSize suggestedSize = SuggestedSize(aIdealKey.Size()); + if (suggestedSize != aIdealKey.Size()) { + if (!exactMatch) { + SurfaceKey compactKey = aIdealKey.CloneWithSize(suggestedSize); + mSurfaces.Get(compactKey, getter_AddRefs(exactMatch)); + if (exactMatch && exactMatch->IsDecoded()) { + MOZ_ASSERT(suggestedSize != aIdealKey.Size()); + return std::make_tuple(exactMatch.forget(), + MatchType::SUBSTITUTE_BECAUSE_BEST, + suggestedSize); + } + } + } + + // There's no perfect match, so find the best match we can. + RefPtr<CachedSurface> bestMatch; + for (const auto& value : Values()) { + NotNull<CachedSurface*> current = WrapNotNull(value); + const SurfaceKey& currentKey = current->GetSurfaceKey(); + + // We never match a placeholder or a surface with a region. + if (current->IsPlaceholder() || currentKey.Region()) { + continue; + } + // Matching the playback type and SVG context is required. + if (currentKey.Playback() != aIdealKey.Playback() || + currentKey.SVGContext() != aIdealKey.SVGContext()) { + continue; + } + // Matching the flags is required. + if (currentKey.Flags() != aIdealKey.Flags()) { + continue; + } + // Anything is better than nothing! (Within the constraints we just + // checked, of course.) + if (!bestMatch) { + bestMatch = current; + continue; + } + + MOZ_ASSERT(bestMatch, "Should have a current best match"); + + // Always prefer completely decoded surfaces. + bool bestMatchIsDecoded = bestMatch->IsDecoded(); + if (bestMatchIsDecoded && !current->IsDecoded()) { + continue; + } + if (!bestMatchIsDecoded && current->IsDecoded()) { + bestMatch = current; + continue; + } + + SurfaceKey bestMatchKey = bestMatch->GetSurfaceKey(); + if (CompareArea(aIdealKey.Size(), bestMatchKey.Size(), + currentKey.Size())) { + bestMatch = current; + } + } + + MatchType matchType; + if (bestMatch) { + if (!exactMatch) { + // No exact match, neither ideal nor factor of 2. + MOZ_ASSERT(suggestedSize != bestMatch->GetSurfaceKey().Size(), + "No exact match despite the fact the sizes match!"); + matchType = MatchType::SUBSTITUTE_BECAUSE_NOT_FOUND; + } else if (exactMatch != bestMatch) { + // The exact match is still decoding, but we found a substitute. + matchType = MatchType::SUBSTITUTE_BECAUSE_PENDING; + } else if (aIdealKey.Size() != bestMatch->GetSurfaceKey().Size()) { + // The best factor of 2 match is still decoding, but the best we've got. + MOZ_ASSERT(suggestedSize != aIdealKey.Size()); + MOZ_ASSERT(mFactor2Mode || mIsVectorImage); + matchType = MatchType::SUBSTITUTE_BECAUSE_BEST; + } else { + // The exact match is still decoding, but it's the best we've got. + matchType = MatchType::EXACT; + } + } else { + if (exactMatch) { + // We found an "exact match"; it must have been a placeholder. + MOZ_ASSERT(exactMatch->IsPlaceholder()); + matchType = MatchType::PENDING; + } else { + // We couldn't find an exact match *or* a substitute. + matchType = MatchType::NOT_FOUND; + } + } + + return std::make_tuple(bestMatch.forget(), matchType, suggestedSize); + } + + void MaybeSetFactor2Mode() { + MOZ_ASSERT(!mFactor2Mode); + + // Typically an image cache will not have too many size-varying surfaces, so + // if we exceed the given threshold, we should consider using a subset. + int32_t thresholdSurfaces = + StaticPrefs::image_cache_factor2_threshold_surfaces(); + if (thresholdSurfaces < 0 || + mSurfaces.Count() <= static_cast<uint32_t>(thresholdSurfaces)) { + return; + } + + // Determine how many native surfaces this image has. If it is zero, and it + // is a vector image, then we should impute a single native size. Otherwise, + // it may be zero because we don't know yet, or the image has an error, or + // it isn't supported. + NotNull<CachedSurface*> current = + WrapNotNull(mSurfaces.ConstIter().UserData()); + Image* image = static_cast<Image*>(current->GetImageKey()); + size_t nativeSizes = image->GetNativeSizesLength(); + if (mIsVectorImage) { + MOZ_ASSERT(nativeSizes == 0); + nativeSizes = 1; + } else if (nativeSizes == 0) { + return; + } + + // Increase the threshold by the number of native sizes. This ensures that + // we do not prevent decoding of the image at all its native sizes. It does + // not guarantee we will provide a surface at that size however (i.e. many + // other sized surfaces are requested, in addition to the native sizes). + thresholdSurfaces += nativeSizes; + if (mSurfaces.Count() <= static_cast<uint32_t>(thresholdSurfaces)) { + return; + } + + // We have a valid size, we can change modes. + mFactor2Mode = true; + } + + template <typename Function> + void Prune(Function&& aRemoveCallback) { + if (!mFactor2Mode || mFactor2Pruned) { + return; + } + + // Attempt to discard any surfaces which are not factor of 2 and the best + // factor of 2 match exists. + bool hasNotFactorSize = false; + for (auto iter = mSurfaces.Iter(); !iter.Done(); iter.Next()) { + NotNull<CachedSurface*> current = WrapNotNull(iter.UserData()); + const SurfaceKey& currentKey = current->GetSurfaceKey(); + const IntSize& currentSize = currentKey.Size(); + + // First we check if someone requested this size and would not accept + // an alternatively sized surface. + if (current->CannotSubstitute()) { + continue; + } + + // Next we find the best factor of 2 size for this surface. If this + // surface is a factor of 2 size, then we want to keep it. + IntSize bestSize = SuggestedSize(currentSize); + if (bestSize == currentSize) { + continue; + } + + // Check the cache for a surface with the same parameters except for the + // size which uses the closest factor of 2 size. + SurfaceKey compactKey = currentKey.CloneWithSize(bestSize); + RefPtr<CachedSurface> compactMatch; + mSurfaces.Get(compactKey, getter_AddRefs(compactMatch)); + if (compactMatch && compactMatch->IsDecoded()) { + aRemoveCallback(current); + iter.Remove(); + } else { + hasNotFactorSize = true; + } + } + + // We have no surfaces that are not factor of 2 sized, so we can stop + // pruning henceforth, because we avoid the insertion of new surfaces that + // don't match our sizing set (unless the caller won't accept a + // substitution.) + if (!hasNotFactorSize) { + mFactor2Pruned = true; + } + + // We should never leave factor of 2 mode due to pruning in of itself, but + // if we discarded surfaces due to the volatile buffers getting released, + // it is possible. + AfterMaybeRemove(); + } + + template <typename Function> + bool Invalidate(Function&& aRemoveCallback) { + // Remove all non-blob recordings from the cache. Invalidate any blob + // recordings. + bool foundRecording = false; + for (auto iter = mSurfaces.Iter(); !iter.Done(); iter.Next()) { + NotNull<CachedSurface*> current = WrapNotNull(iter.UserData()); + + if (current->GetSurfaceKey().Flags() & SurfaceFlags::RECORD_BLOB) { + foundRecording = true; + current->InvalidateRecording(); + continue; + } + + aRemoveCallback(current); + iter.Remove(); + } + + AfterMaybeRemove(); + return foundRecording; + } + + IntSize SuggestedSize(const IntSize& aSize) const { + IntSize suggestedSize = SuggestedSizeInternal(aSize); + if (mIsVectorImage) { + suggestedSize = SurfaceCache::ClampVectorSize(suggestedSize); + } + return suggestedSize; + } + + IntSize SuggestedSizeInternal(const IntSize& aSize) const { + // When not in factor of 2 mode, we can always decode at the given size. + if (!mFactor2Mode) { + return aSize; + } + + // We cannot enter factor of 2 mode unless we have a minimum number of + // surfaces, and we should have left it if the cache was emptied. + if (MOZ_UNLIKELY(IsEmpty())) { + MOZ_ASSERT_UNREACHABLE("Should not be empty and in factor of 2 mode!"); + return aSize; + } + + // This bit of awkwardness gets the largest native size of the image. + NotNull<CachedSurface*> firstSurface = + WrapNotNull(mSurfaces.ConstIter().UserData()); + Image* image = static_cast<Image*>(firstSurface->GetImageKey()); + IntSize factorSize; + if (NS_FAILED(image->GetWidth(&factorSize.width)) || + NS_FAILED(image->GetHeight(&factorSize.height)) || + factorSize.IsEmpty()) { + // Valid vector images may have a default size of 0x0. In that case, just + // assume a default size of 100x100 and apply the intrinsic ratio if + // available. If our guess was too small, don't use factor-of-scaling. + MOZ_ASSERT(mIsVectorImage); + factorSize = IntSize(100, 100); + Maybe<AspectRatio> aspectRatio = image->GetIntrinsicRatio(); + if (aspectRatio && *aspectRatio) { + factorSize.width = + NSToIntRound(aspectRatio->ApplyToFloat(float(factorSize.height))); + if (factorSize.IsEmpty()) { + return aSize; + } + } + } + + if (mIsVectorImage) { + // Ensure the aspect ratio matches the native size before forcing the + // caller to accept a factor of 2 size. The difference between the aspect + // ratios is: + // + // delta = nativeWidth/nativeHeight - desiredWidth/desiredHeight + // + // delta*nativeHeight*desiredHeight = nativeWidth*desiredHeight + // - desiredWidth*nativeHeight + // + // Using the maximum accepted delta as a constant, we can avoid the + // floating point division and just compare after some integer ops. + int32_t delta = + factorSize.width * aSize.height - aSize.width * factorSize.height; + int32_t maxDelta = (factorSize.height * aSize.height) >> 4; + if (delta > maxDelta || delta < -maxDelta) { + return aSize; + } + + // If the requested size is bigger than the native size, we actually need + // to grow the native size instead of shrinking it. + if (factorSize.width < aSize.width) { + do { + IntSize candidate(factorSize.width * 2, factorSize.height * 2); + if (!SurfaceCache::IsLegalSize(candidate)) { + break; + } + + factorSize = candidate; + } while (factorSize.width < aSize.width); + + return factorSize; + } + + // Otherwise we can find the best fit as normal. + } + + // Start with the native size as the best first guess. + IntSize bestSize = factorSize; + factorSize.width /= 2; + factorSize.height /= 2; + + while (!factorSize.IsEmpty()) { + if (!CompareArea(aSize, bestSize, factorSize)) { + // This size is not better than the last. Since we proceed from largest + // to smallest, we know that the next size will not be better if the + // previous size was rejected. Break early. + break; + } + + // The current factor of 2 size is better than the last selected size. + bestSize = factorSize; + factorSize.width /= 2; + factorSize.height /= 2; + } + + return bestSize; + } + + bool CompareArea(const IntSize& aIdealSize, const IntSize& aBestSize, + const IntSize& aSize) const { + // Compare sizes. We use an area-based heuristic here instead of computing a + // truly optimal answer, since it seems very unlikely to make a difference + // for realistic sizes. + int64_t idealArea = AreaOfIntSize(aIdealSize); + int64_t currentArea = AreaOfIntSize(aSize); + int64_t bestMatchArea = AreaOfIntSize(aBestSize); + + // If the best match is smaller than the ideal size, prefer bigger sizes. + if (bestMatchArea < idealArea) { + if (currentArea > bestMatchArea) { + return true; + } + return false; + } + + // Other, prefer sizes closer to the ideal size, but still not smaller. + if (idealArea <= currentArea && currentArea < bestMatchArea) { + return true; + } + + // This surface isn't an improvement over the current best match. + return false; + } + + template <typename Function> + void CollectSizeOfSurfaces(nsTArray<SurfaceMemoryCounter>& aCounters, + MallocSizeOf aMallocSizeOf, + Function&& aRemoveCallback) { + CachedSurface::SurfaceMemoryReport report(aCounters, aMallocSizeOf); + for (auto iter = mSurfaces.Iter(); !iter.Done(); iter.Next()) { + NotNull<CachedSurface*> surface = WrapNotNull(iter.UserData()); + + // We don't need the drawable surface for ourselves, but adding a surface + // to the report will trigger this indirectly. If the surface was + // discarded by the OS because it was in volatile memory, we should remove + // it from the cache immediately rather than include it in the report. + DrawableSurface drawableSurface; + if (!surface->IsPlaceholder()) { + drawableSurface = surface->GetDrawableSurface(); + if (!drawableSurface) { + aRemoveCallback(surface); + iter.Remove(); + continue; + } + } + + const IntSize& size = surface->GetSurfaceKey().Size(); + bool factor2Size = false; + if (mFactor2Mode) { + factor2Size = (size == SuggestedSize(size)); + } + report.Add(surface, factor2Size); + } + + AfterMaybeRemove(); + } + + void SetLocked(bool aLocked) { mLocked = aLocked; } + bool IsLocked() const { return mLocked; } + + private: + void AfterMaybeRemove() { + if (IsEmpty() && mFactor2Mode) { + // The last surface for this cache was removed. This can happen if the + // surface was stored in a volatile buffer and got purged, or the surface + // expired from the cache. If the cache itself lingers for some reason + // (e.g. in the process of performing a lookup, the cache itself is + // locked), then we need to reset the factor of 2 state because it + // requires at least one surface present to get the native size + // information from the image. + mFactor2Mode = mFactor2Pruned = false; + } + } + + SurfaceTable mSurfaces; + + bool mLocked; + + // True in "factor of 2" mode. + bool mFactor2Mode; + + // True if all non-factor of 2 surfaces have been removed from the cache. Note + // that this excludes unsubstitutable sizes. + bool mFactor2Pruned; + + // True if the surfaces are produced from a vector image. If so, it must match + // the aspect ratio when using factor of 2 mode. + bool mIsVectorImage; +}; + +/** + * SurfaceCacheImpl is responsible for determining which surfaces will be cached + * and managing the surface cache data structures. Rather than interact with + * SurfaceCacheImpl directly, client code interacts with SurfaceCache, which + * maintains high-level invariants and encapsulates the details of the surface + * cache's implementation. + */ +class SurfaceCacheImpl final : public nsIMemoryReporter { + public: + NS_DECL_ISUPPORTS + + SurfaceCacheImpl(uint32_t aSurfaceCacheExpirationTimeMS, + uint32_t aSurfaceCacheDiscardFactor, + uint32_t aSurfaceCacheSize) + : mExpirationTracker(aSurfaceCacheExpirationTimeMS), + mMemoryPressureObserver(new MemoryPressureObserver), + mDiscardFactor(aSurfaceCacheDiscardFactor), + mMaxCost(aSurfaceCacheSize), + mAvailableCost(aSurfaceCacheSize), + mLockedCost(0), + mOverflowCount(0), + mAlreadyPresentCount(0), + mTableFailureCount(0), + mTrackingFailureCount(0) { + nsCOMPtr<nsIObserverService> os = services::GetObserverService(); + if (os) { + os->AddObserver(mMemoryPressureObserver, "memory-pressure", false); + } + } + + private: + virtual ~SurfaceCacheImpl() { + nsCOMPtr<nsIObserverService> os = services::GetObserverService(); + if (os) { + os->RemoveObserver(mMemoryPressureObserver, "memory-pressure"); + } + + UnregisterWeakMemoryReporter(this); + } + + public: + void InitMemoryReporter() { RegisterWeakMemoryReporter(this); } + + InsertOutcome Insert(NotNull<ISurfaceProvider*> aProvider, bool aSetAvailable, + const StaticMutexAutoLock& aAutoLock) { + // If this is a duplicate surface, refuse to replace the original. + // XXX(seth): Calling Lookup() and then RemoveEntry() does the lookup + // twice. We'll make this more efficient in bug 1185137. + LookupResult result = + Lookup(aProvider->GetImageKey(), aProvider->GetSurfaceKey(), aAutoLock, + /* aMarkUsed = */ false); + if (MOZ_UNLIKELY(result)) { + mAlreadyPresentCount++; + return InsertOutcome::FAILURE_ALREADY_PRESENT; + } + + if (result.Type() == MatchType::PENDING) { + RemoveEntry(aProvider->GetImageKey(), aProvider->GetSurfaceKey(), + aAutoLock); + } + + MOZ_ASSERT(result.Type() == MatchType::NOT_FOUND || + result.Type() == MatchType::PENDING, + "A LookupResult with no surface should be NOT_FOUND or PENDING"); + + // If this is bigger than we can hold after discarding everything we can, + // refuse to cache it. + Cost cost = aProvider->LogicalSizeInBytes(); + if (MOZ_UNLIKELY(!CanHoldAfterDiscarding(cost))) { + mOverflowCount++; + return InsertOutcome::FAILURE; + } + + // Remove elements in order of cost until we can fit this in the cache. Note + // that locked surfaces aren't in mCosts, so we never remove them here. + while (cost > mAvailableCost) { + MOZ_ASSERT(!mCosts.IsEmpty(), + "Removed everything and it still won't fit"); + Remove(mCosts.LastElement().Surface(), /* aStopTracking */ true, + aAutoLock); + } + + // Locate the appropriate per-image cache. If there's not an existing cache + // for this image, create it. + const ImageKey imageKey = aProvider->GetImageKey(); + RefPtr<ImageSurfaceCache> cache = GetImageCache(imageKey); + if (!cache) { + cache = new ImageSurfaceCache(imageKey); + if (!mImageCaches.InsertOrUpdate(aProvider->GetImageKey(), RefPtr{cache}, + fallible)) { + mTableFailureCount++; + return InsertOutcome::FAILURE; + } + } + + // If we were asked to mark the cache entry available, do so. + if (aSetAvailable) { + aProvider->Availability().SetAvailable(); + } + + auto surface = MakeNotNull<RefPtr<CachedSurface>>(aProvider); + + // We require that locking succeed if the image is locked and we're not + // inserting a placeholder; the caller may need to know this to handle + // errors correctly. + bool mustLock = cache->IsLocked() && !surface->IsPlaceholder(); + if (mustLock) { + surface->SetLocked(true); + if (!surface->IsLocked()) { + return InsertOutcome::FAILURE; + } + } + + // Insert. + MOZ_ASSERT(cost <= mAvailableCost, "Inserting despite too large a cost"); + if (!cache->Insert(surface)) { + mTableFailureCount++; + if (mustLock) { + surface->SetLocked(false); + } + return InsertOutcome::FAILURE; + } + + if (MOZ_UNLIKELY(!StartTracking(surface, aAutoLock))) { + MOZ_ASSERT(!mustLock); + Remove(surface, /* aStopTracking */ false, aAutoLock); + return InsertOutcome::FAILURE; + } + + return InsertOutcome::SUCCESS; + } + + void Remove(NotNull<CachedSurface*> aSurface, bool aStopTracking, + const StaticMutexAutoLock& aAutoLock) { + ImageKey imageKey = aSurface->GetImageKey(); + + RefPtr<ImageSurfaceCache> cache = GetImageCache(imageKey); + MOZ_ASSERT(cache, "Shouldn't try to remove a surface with no image cache"); + + // If the surface was not a placeholder, tell its image that we discarded + // it. + if (!aSurface->IsPlaceholder()) { + static_cast<Image*>(imageKey)->OnSurfaceDiscarded( + aSurface->GetSurfaceKey()); + } + + // If we failed during StartTracking, we can skip this step. + if (aStopTracking) { + StopTracking(aSurface, /* aIsTracked */ true, aAutoLock); + } + + // Individual surfaces must be freed outside the lock. + mCachedSurfacesDiscard.AppendElement(cache->Remove(aSurface)); + + MaybeRemoveEmptyCache(imageKey, cache); + } + + bool StartTracking(NotNull<CachedSurface*> aSurface, + const StaticMutexAutoLock& aAutoLock) { + CostEntry costEntry = aSurface->GetCostEntry(); + MOZ_ASSERT(costEntry.GetCost() <= mAvailableCost, + "Cost too large and the caller didn't catch it"); + + if (aSurface->IsLocked()) { + mLockedCost += costEntry.GetCost(); + MOZ_ASSERT(mLockedCost <= mMaxCost, "Locked more than we can hold?"); + } else { + if (NS_WARN_IF(!mCosts.InsertElementSorted(costEntry, fallible))) { + mTrackingFailureCount++; + return false; + } + + // This may fail during XPCOM shutdown, so we need to ensure the object is + // tracked before calling RemoveObject in StopTracking. + nsresult rv = mExpirationTracker.AddObjectLocked(aSurface, aAutoLock); + if (NS_WARN_IF(NS_FAILED(rv))) { + DebugOnly<bool> foundInCosts = mCosts.RemoveElementSorted(costEntry); + MOZ_ASSERT(foundInCosts, "Lost track of costs for this surface"); + mTrackingFailureCount++; + return false; + } + } + + mAvailableCost -= costEntry.GetCost(); + return true; + } + + void StopTracking(NotNull<CachedSurface*> aSurface, bool aIsTracked, + const StaticMutexAutoLock& aAutoLock) { + CostEntry costEntry = aSurface->GetCostEntry(); + + if (aSurface->IsLocked()) { + MOZ_ASSERT(mLockedCost >= costEntry.GetCost(), "Costs don't balance"); + mLockedCost -= costEntry.GetCost(); + // XXX(seth): It'd be nice to use an O(log n) lookup here. This is O(n). + MOZ_ASSERT(!mCosts.Contains(costEntry), + "Shouldn't have a cost entry for a locked surface"); + } else { + if (MOZ_LIKELY(aSurface->GetExpirationState()->IsTracked())) { + MOZ_ASSERT(aIsTracked, "Expiration-tracking a surface unexpectedly!"); + mExpirationTracker.RemoveObjectLocked(aSurface, aAutoLock); + } else { + // Our call to AddObject must have failed in StartTracking; most likely + // we're in XPCOM shutdown right now. + MOZ_ASSERT(!aIsTracked, "Not expiration-tracking an unlocked surface!"); + } + + DebugOnly<bool> foundInCosts = mCosts.RemoveElementSorted(costEntry); + MOZ_ASSERT(foundInCosts, "Lost track of costs for this surface"); + } + + mAvailableCost += costEntry.GetCost(); + MOZ_ASSERT(mAvailableCost <= mMaxCost, + "More available cost than we started with"); + } + + LookupResult Lookup(const ImageKey aImageKey, const SurfaceKey& aSurfaceKey, + const StaticMutexAutoLock& aAutoLock, bool aMarkUsed) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + // No cached surfaces for this image. + return LookupResult(MatchType::NOT_FOUND); + } + + RefPtr<CachedSurface> surface = cache->Lookup(aSurfaceKey, aMarkUsed); + if (!surface) { + // Lookup in the per-image cache missed. + return LookupResult(MatchType::NOT_FOUND); + } + + if (surface->IsPlaceholder()) { + return LookupResult(MatchType::PENDING); + } + + DrawableSurface drawableSurface = surface->GetDrawableSurface(); + if (!drawableSurface) { + // The surface was released by the operating system. Remove the cache + // entry as well. + Remove(WrapNotNull(surface), /* aStopTracking */ true, aAutoLock); + return LookupResult(MatchType::NOT_FOUND); + } + + if (aMarkUsed && + !MarkUsed(WrapNotNull(surface), WrapNotNull(cache), aAutoLock)) { + Remove(WrapNotNull(surface), /* aStopTracking */ false, aAutoLock); + return LookupResult(MatchType::NOT_FOUND); + } + + MOZ_ASSERT(surface->GetSurfaceKey() == aSurfaceKey, + "Lookup() not returning an exact match?"); + return LookupResult(std::move(drawableSurface), MatchType::EXACT); + } + + LookupResult LookupBestMatch(const ImageKey aImageKey, + const SurfaceKey& aSurfaceKey, + const StaticMutexAutoLock& aAutoLock, + bool aMarkUsed) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + // No cached surfaces for this image. + return LookupResult( + MatchType::NOT_FOUND, + SurfaceCache::ClampSize(aImageKey, aSurfaceKey.Size())); + } + + // Repeatedly look up the best match, trying again if the resulting surface + // has been freed by the operating system, until we can either lock a + // surface for drawing or there are no matching surfaces left. + // XXX(seth): This is O(N^2), but N is expected to be very small. If we + // encounter a performance problem here we can revisit this. + + RefPtr<CachedSurface> surface; + DrawableSurface drawableSurface; + MatchType matchType = MatchType::NOT_FOUND; + IntSize suggestedSize; + while (true) { + std::tie(surface, matchType, suggestedSize) = + cache->LookupBestMatch(aSurfaceKey); + + if (!surface) { + return LookupResult( + matchType, suggestedSize); // Lookup in the per-image cache missed. + } + + drawableSurface = surface->GetDrawableSurface(); + if (drawableSurface) { + break; + } + + // The surface was released by the operating system. Remove the cache + // entry as well. + Remove(WrapNotNull(surface), /* aStopTracking */ true, aAutoLock); + } + + MOZ_ASSERT_IF(matchType == MatchType::EXACT, + surface->GetSurfaceKey() == aSurfaceKey); + MOZ_ASSERT_IF( + matchType == MatchType::SUBSTITUTE_BECAUSE_NOT_FOUND || + matchType == MatchType::SUBSTITUTE_BECAUSE_PENDING, + surface->GetSurfaceKey().Region() == aSurfaceKey.Region() && + surface->GetSurfaceKey().SVGContext() == aSurfaceKey.SVGContext() && + surface->GetSurfaceKey().Playback() == aSurfaceKey.Playback() && + surface->GetSurfaceKey().Flags() == aSurfaceKey.Flags()); + + if (matchType == MatchType::EXACT || + matchType == MatchType::SUBSTITUTE_BECAUSE_BEST) { + if (aMarkUsed && + !MarkUsed(WrapNotNull(surface), WrapNotNull(cache), aAutoLock)) { + Remove(WrapNotNull(surface), /* aStopTracking */ false, aAutoLock); + } + } + + return LookupResult(std::move(drawableSurface), matchType, suggestedSize); + } + + bool CanHold(const Cost aCost) const { return aCost <= mMaxCost; } + + size_t MaximumCapacity() const { return size_t(mMaxCost); } + + void SurfaceAvailable(NotNull<ISurfaceProvider*> aProvider, + const StaticMutexAutoLock& aAutoLock) { + if (!aProvider->Availability().IsPlaceholder()) { + MOZ_ASSERT_UNREACHABLE("Calling SurfaceAvailable on non-placeholder"); + return; + } + + // Reinsert the provider, requesting that Insert() mark it available. This + // may or may not succeed, depending on whether some other decoder has + // beaten us to the punch and inserted a non-placeholder version of this + // surface first, but it's fine either way. + // XXX(seth): This could be implemented more efficiently; we should be able + // to just update our data structures without reinserting. + Insert(aProvider, /* aSetAvailable = */ true, aAutoLock); + } + + void LockImage(const ImageKey aImageKey) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + cache = new ImageSurfaceCache(aImageKey); + mImageCaches.InsertOrUpdate(aImageKey, RefPtr{cache}); + } + + cache->SetLocked(true); + + // We don't relock this image's existing surfaces right away; instead, the + // image should arrange for Lookup() to touch them if they are still useful. + } + + void UnlockImage(const ImageKey aImageKey, + const StaticMutexAutoLock& aAutoLock) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache || !cache->IsLocked()) { + return; // Already unlocked. + } + + cache->SetLocked(false); + DoUnlockSurfaces(WrapNotNull(cache), /* aStaticOnly = */ false, aAutoLock); + } + + void UnlockEntries(const ImageKey aImageKey, + const StaticMutexAutoLock& aAutoLock) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache || !cache->IsLocked()) { + return; // Already unlocked. + } + + // (Note that we *don't* unlock the per-image cache here; that's the + // difference between this and UnlockImage.) + DoUnlockSurfaces(WrapNotNull(cache), + /* aStaticOnly = */ + !StaticPrefs::image_mem_animated_discardable_AtStartup(), + aAutoLock); + } + + already_AddRefed<ImageSurfaceCache> RemoveImage( + const ImageKey aImageKey, const StaticMutexAutoLock& aAutoLock) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + return nullptr; // No cached surfaces for this image, so nothing to do. + } + + // Discard all of the cached surfaces for this image. + // XXX(seth): This is O(n^2) since for each item in the cache we are + // removing an element from the costs array. Since n is expected to be + // small, performance should be good, but if usage patterns change we should + // change the data structure used for mCosts. + for (const auto& value : cache->Values()) { + StopTracking(WrapNotNull(value), + /* aIsTracked */ true, aAutoLock); + } + + // The per-image cache isn't needed anymore, so remove it as well. + // This implicitly unlocks the image if it was locked. + mImageCaches.Remove(aImageKey); + + // Since we did not actually remove any of the surfaces from the cache + // itself, only stopped tracking them, we should free it outside the lock. + return cache.forget(); + } + + void PruneImage(const ImageKey aImageKey, + const StaticMutexAutoLock& aAutoLock) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + return; // No cached surfaces for this image, so nothing to do. + } + + cache->Prune([this, &aAutoLock](NotNull<CachedSurface*> aSurface) -> void { + StopTracking(aSurface, /* aIsTracked */ true, aAutoLock); + // Individual surfaces must be freed outside the lock. + mCachedSurfacesDiscard.AppendElement(aSurface); + }); + + MaybeRemoveEmptyCache(aImageKey, cache); + } + + bool InvalidateImage(const ImageKey aImageKey, + const StaticMutexAutoLock& aAutoLock) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + return false; // No cached surfaces for this image, so nothing to do. + } + + bool rv = cache->Invalidate( + [this, &aAutoLock](NotNull<CachedSurface*> aSurface) -> void { + StopTracking(aSurface, /* aIsTracked */ true, aAutoLock); + // Individual surfaces must be freed outside the lock. + mCachedSurfacesDiscard.AppendElement(aSurface); + }); + + MaybeRemoveEmptyCache(aImageKey, cache); + return rv; + } + + void DiscardAll(const StaticMutexAutoLock& aAutoLock) { + // Remove in order of cost because mCosts is an array and the other data + // structures are all hash tables. Note that locked surfaces are not + // removed, since they aren't present in mCosts. + while (!mCosts.IsEmpty()) { + Remove(mCosts.LastElement().Surface(), /* aStopTracking */ true, + aAutoLock); + } + } + + void DiscardForMemoryPressure(const StaticMutexAutoLock& aAutoLock) { + // Compute our discardable cost. Since locked surfaces aren't discardable, + // we exclude them. + const Cost discardableCost = (mMaxCost - mAvailableCost) - mLockedCost; + MOZ_ASSERT(discardableCost <= mMaxCost, "Discardable cost doesn't add up"); + + // Our target is to raise our available cost by (1 / mDiscardFactor) of our + // discardable cost - in other words, we want to end up with about + // (discardableCost / mDiscardFactor) fewer bytes stored in the surface + // cache after we're done. + const Cost targetCost = mAvailableCost + (discardableCost / mDiscardFactor); + + if (targetCost > mMaxCost - mLockedCost) { + MOZ_ASSERT_UNREACHABLE("Target cost is more than we can discard"); + DiscardAll(aAutoLock); + return; + } + + // Discard surfaces until we've reduced our cost to our target cost. + while (mAvailableCost < targetCost) { + MOZ_ASSERT(!mCosts.IsEmpty(), "Removed everything and still not done"); + Remove(mCosts.LastElement().Surface(), /* aStopTracking */ true, + aAutoLock); + } + } + + void TakeDiscard(nsTArray<RefPtr<CachedSurface>>& aDiscard, + const StaticMutexAutoLock& aAutoLock) { + MOZ_ASSERT(aDiscard.IsEmpty()); + aDiscard = std::move(mCachedSurfacesDiscard); + } + + already_AddRefed<CachedSurface> GetSurfaceForResetAnimation( + const ImageKey aImageKey, const SurfaceKey& aSurfaceKey, + const StaticMutexAutoLock& aAutoLock) { + RefPtr<CachedSurface> surface; + + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + // No cached surfaces for this image. + return surface.forget(); + } + + surface = cache->Lookup(aSurfaceKey, /* aForAccess = */ false); + return surface.forget(); + } + + void LockSurface(NotNull<CachedSurface*> aSurface, + const StaticMutexAutoLock& aAutoLock) { + if (aSurface->IsPlaceholder() || aSurface->IsLocked()) { + return; + } + + StopTracking(aSurface, /* aIsTracked */ true, aAutoLock); + + // Lock the surface. This can fail. + aSurface->SetLocked(true); + DebugOnly<bool> tracked = StartTracking(aSurface, aAutoLock); + MOZ_ASSERT(tracked); + } + + size_t ShallowSizeOfIncludingThis( + MallocSizeOf aMallocSizeOf, const StaticMutexAutoLock& aAutoLock) const { + size_t bytes = + aMallocSizeOf(this) + mCosts.ShallowSizeOfExcludingThis(aMallocSizeOf) + + mImageCaches.ShallowSizeOfExcludingThis(aMallocSizeOf) + + mCachedSurfacesDiscard.ShallowSizeOfExcludingThis(aMallocSizeOf) + + mExpirationTracker.ShallowSizeOfExcludingThis(aMallocSizeOf); + for (const auto& data : mImageCaches.Values()) { + bytes += data->ShallowSizeOfIncludingThis(aMallocSizeOf); + } + return bytes; + } + + NS_IMETHOD + CollectReports(nsIHandleReportCallback* aHandleReport, nsISupports* aData, + bool aAnonymize) override { + StaticMutexAutoLock lock(sInstanceMutex); + + uint32_t lockedImageCount = 0; + uint32_t totalSurfaceCount = 0; + uint32_t lockedSurfaceCount = 0; + for (const auto& cache : mImageCaches.Values()) { + totalSurfaceCount += cache->Count(); + if (cache->IsLocked()) { + ++lockedImageCount; + } + for (const auto& value : cache->Values()) { + if (value->IsLocked()) { + ++lockedSurfaceCount; + } + } + } + + // clang-format off + // We have explicit memory reporting for the surface cache which is more + // accurate than the cost metrics we report here, but these metrics are + // still useful to report, since they control the cache's behavior. + MOZ_COLLECT_REPORT( + "explicit/images/cache/overhead", KIND_HEAP, UNITS_BYTES, + ShallowSizeOfIncludingThis(SurfaceCacheMallocSizeOf, lock), +"Memory used by the surface cache data structures, excluding surface data."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-estimated-total", + KIND_OTHER, UNITS_BYTES, (mMaxCost - mAvailableCost), +"Estimated total memory used by the imagelib surface cache."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-estimated-locked", + KIND_OTHER, UNITS_BYTES, mLockedCost, +"Estimated memory used by locked surfaces in the imagelib surface cache."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-tracked-cost-count", + KIND_OTHER, UNITS_COUNT, mCosts.Length(), +"Total number of surfaces tracked for cost (and expiry) in the imagelib surface cache."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-tracked-expiry-count", + KIND_OTHER, UNITS_COUNT, mExpirationTracker.Length(lock), +"Total number of surfaces tracked for expiry (and cost) in the imagelib surface cache."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-image-count", + KIND_OTHER, UNITS_COUNT, mImageCaches.Count(), +"Total number of images in the imagelib surface cache."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-locked-image-count", + KIND_OTHER, UNITS_COUNT, lockedImageCount, +"Total number of locked images in the imagelib surface cache."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-image-surface-count", + KIND_OTHER, UNITS_COUNT, totalSurfaceCount, +"Total number of surfaces in the imagelib surface cache."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-locked-surfaces-count", + KIND_OTHER, UNITS_COUNT, lockedSurfaceCount, +"Total number of locked surfaces in the imagelib surface cache."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-overflow-count", + KIND_OTHER, UNITS_COUNT, mOverflowCount, +"Count of how many times the surface cache has hit its capacity and been " +"unable to insert a new surface."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-tracking-failure-count", + KIND_OTHER, UNITS_COUNT, mTrackingFailureCount, +"Count of how many times the surface cache has failed to begin tracking a " +"given surface."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-already-present-count", + KIND_OTHER, UNITS_COUNT, mAlreadyPresentCount, +"Count of how many times the surface cache has failed to insert a surface " +"because it is already present."); + + MOZ_COLLECT_REPORT( + "imagelib-surface-cache-table-failure-count", + KIND_OTHER, UNITS_COUNT, mTableFailureCount, +"Count of how many times the surface cache has failed to insert a surface " +"because a hash table could not accept an entry."); + // clang-format on + + return NS_OK; + } + + void CollectSizeOfSurfaces(const ImageKey aImageKey, + nsTArray<SurfaceMemoryCounter>& aCounters, + MallocSizeOf aMallocSizeOf, + const StaticMutexAutoLock& aAutoLock) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + return; // No surfaces for this image. + } + + // Report all surfaces in the per-image cache. + cache->CollectSizeOfSurfaces( + aCounters, aMallocSizeOf, + [this, &aAutoLock](NotNull<CachedSurface*> aSurface) -> void { + StopTracking(aSurface, /* aIsTracked */ true, aAutoLock); + // Individual surfaces must be freed outside the lock. + mCachedSurfacesDiscard.AppendElement(aSurface); + }); + + MaybeRemoveEmptyCache(aImageKey, cache); + } + + void ReleaseImageOnMainThread(already_AddRefed<image::Image>&& aImage, + const StaticMutexAutoLock& aAutoLock) { + RefPtr<image::Image> image = aImage; + if (!image) { + return; + } + + bool needsDispatch = mReleasingImagesOnMainThread.IsEmpty(); + mReleasingImagesOnMainThread.AppendElement(image); + + if (!needsDispatch || + AppShutdown::IsInOrBeyond(ShutdownPhase::XPCOMShutdownFinal)) { + // Either there is already a ongoing task for ClearReleasingImages() or + // it's too late in shutdown to dispatch. + return; + } + + NS_DispatchToMainThread(NS_NewRunnableFunction( + "SurfaceCacheImpl::ReleaseImageOnMainThread", + []() -> void { SurfaceCache::ClearReleasingImages(); })); + } + + void TakeReleasingImages(nsTArray<RefPtr<image::Image>>& aImage, + const StaticMutexAutoLock& aAutoLock) { + MOZ_ASSERT(NS_IsMainThread()); + aImage.SwapElements(mReleasingImagesOnMainThread); + } + + private: + already_AddRefed<ImageSurfaceCache> GetImageCache(const ImageKey aImageKey) { + RefPtr<ImageSurfaceCache> imageCache; + mImageCaches.Get(aImageKey, getter_AddRefs(imageCache)); + return imageCache.forget(); + } + + void MaybeRemoveEmptyCache(const ImageKey aImageKey, + ImageSurfaceCache* aCache) { + // Remove the per-image cache if it's unneeded now. Keep it if the image is + // locked, since the per-image cache is where we store that state. Note that + // we don't push it into mImageCachesDiscard because all of its surfaces + // have been removed, so it is safe to free while holding the lock. + if (aCache->IsEmpty() && !aCache->IsLocked()) { + mImageCaches.Remove(aImageKey); + } + } + + // This is similar to CanHold() except that it takes into account the costs of + // locked surfaces. It's used internally in Insert(), but it's not exposed + // publicly because we permit multithreaded access to the surface cache, which + // means that the result would be meaningless: another thread could insert a + // surface or lock an image at any time. + bool CanHoldAfterDiscarding(const Cost aCost) const { + return aCost <= mMaxCost - mLockedCost; + } + + bool MarkUsed(NotNull<CachedSurface*> aSurface, + NotNull<ImageSurfaceCache*> aCache, + const StaticMutexAutoLock& aAutoLock) { + if (aCache->IsLocked()) { + LockSurface(aSurface, aAutoLock); + return true; + } + + nsresult rv = mExpirationTracker.MarkUsedLocked(aSurface, aAutoLock); + if (NS_WARN_IF(NS_FAILED(rv))) { + // If mark used fails, it is because it failed to reinsert the surface + // after removing it from the tracker. Thus we need to update our + // own accounting but otherwise expect it to be untracked. + StopTracking(aSurface, /* aIsTracked */ false, aAutoLock); + return false; + } + return true; + } + + void DoUnlockSurfaces(NotNull<ImageSurfaceCache*> aCache, bool aStaticOnly, + const StaticMutexAutoLock& aAutoLock) { + AutoTArray<NotNull<CachedSurface*>, 8> discard; + + // Unlock all the surfaces the per-image cache is holding. + for (const auto& value : aCache->Values()) { + NotNull<CachedSurface*> surface = WrapNotNull(value); + if (surface->IsPlaceholder() || !surface->IsLocked()) { + continue; + } + if (aStaticOnly && + surface->GetSurfaceKey().Playback() != PlaybackType::eStatic) { + continue; + } + StopTracking(surface, /* aIsTracked */ true, aAutoLock); + surface->SetLocked(false); + if (MOZ_UNLIKELY(!StartTracking(surface, aAutoLock))) { + discard.AppendElement(surface); + } + } + + // Discard any that we failed to track. + for (auto iter = discard.begin(); iter != discard.end(); ++iter) { + Remove(*iter, /* aStopTracking */ false, aAutoLock); + } + } + + void RemoveEntry(const ImageKey aImageKey, const SurfaceKey& aSurfaceKey, + const StaticMutexAutoLock& aAutoLock) { + RefPtr<ImageSurfaceCache> cache = GetImageCache(aImageKey); + if (!cache) { + return; // No cached surfaces for this image. + } + + RefPtr<CachedSurface> surface = + cache->Lookup(aSurfaceKey, /* aForAccess = */ false); + if (!surface) { + return; // Lookup in the per-image cache missed. + } + + Remove(WrapNotNull(surface), /* aStopTracking */ true, aAutoLock); + } + + class SurfaceTracker final + : public ExpirationTrackerImpl<CachedSurface, 2, StaticMutex, + StaticMutexAutoLock> { + public: + explicit SurfaceTracker(uint32_t aSurfaceCacheExpirationTimeMS) + : ExpirationTrackerImpl<CachedSurface, 2, StaticMutex, + StaticMutexAutoLock>( + aSurfaceCacheExpirationTimeMS, "SurfaceTracker") {} + + protected: + void NotifyExpiredLocked(CachedSurface* aSurface, + const StaticMutexAutoLock& aAutoLock) override { + sInstance->Remove(WrapNotNull(aSurface), /* aStopTracking */ true, + aAutoLock); + } + + void NotifyHandlerEndLocked(const StaticMutexAutoLock& aAutoLock) override { + sInstance->TakeDiscard(mDiscard, aAutoLock); + } + + void NotifyHandlerEnd() override { + nsTArray<RefPtr<CachedSurface>> discard(std::move(mDiscard)); + } + + StaticMutex& GetMutex() override { return sInstanceMutex; } + + nsTArray<RefPtr<CachedSurface>> mDiscard; + }; + + class MemoryPressureObserver final : public nsIObserver { + public: + NS_DECL_ISUPPORTS + + NS_IMETHOD Observe(nsISupports*, const char* aTopic, + const char16_t*) override { + nsTArray<RefPtr<CachedSurface>> discard; + { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance && strcmp(aTopic, "memory-pressure") == 0) { + sInstance->DiscardForMemoryPressure(lock); + sInstance->TakeDiscard(discard, lock); + } + } + return NS_OK; + } + + private: + virtual ~MemoryPressureObserver() {} + }; + + nsTArray<CostEntry> mCosts; + nsRefPtrHashtable<nsPtrHashKey<Image>, ImageSurfaceCache> mImageCaches; + nsTArray<RefPtr<CachedSurface>> mCachedSurfacesDiscard; + SurfaceTracker mExpirationTracker; + RefPtr<MemoryPressureObserver> mMemoryPressureObserver; + nsTArray<RefPtr<image::Image>> mReleasingImagesOnMainThread; + const uint32_t mDiscardFactor; + const Cost mMaxCost; + Cost mAvailableCost; + Cost mLockedCost; + size_t mOverflowCount; + size_t mAlreadyPresentCount; + size_t mTableFailureCount; + size_t mTrackingFailureCount; +}; + +NS_IMPL_ISUPPORTS(SurfaceCacheImpl, nsIMemoryReporter) +NS_IMPL_ISUPPORTS(SurfaceCacheImpl::MemoryPressureObserver, nsIObserver) + +/////////////////////////////////////////////////////////////////////////////// +// Public API +/////////////////////////////////////////////////////////////////////////////// + +/* static */ +void SurfaceCache::Initialize() { + // Initialize preferences. + MOZ_ASSERT(NS_IsMainThread()); + MOZ_ASSERT(!sInstance, "Shouldn't initialize more than once"); + + // See StaticPrefs for the default values of these preferences. + + // Length of time before an unused surface is removed from the cache, in + // milliseconds. + uint32_t surfaceCacheExpirationTimeMS = + StaticPrefs::image_mem_surfacecache_min_expiration_ms_AtStartup(); + + // What fraction of the memory used by the surface cache we should discard + // when we get a memory pressure notification. This value is interpreted as + // 1/N, so 1 means to discard everything, 2 means to discard about half of the + // memory we're using, and so forth. We clamp it to avoid division by zero. + uint32_t surfaceCacheDiscardFactor = + max(StaticPrefs::image_mem_surfacecache_discard_factor_AtStartup(), 1u); + + // Maximum size of the surface cache, in kilobytes. + uint64_t surfaceCacheMaxSizeKB = + StaticPrefs::image_mem_surfacecache_max_size_kb_AtStartup(); + + if (sizeof(uintptr_t) <= 4) { + // Limit surface cache to 1 GB if our address space is 32 bit. + surfaceCacheMaxSizeKB = 1024 * 1024; + } + + // A knob determining the actual size of the surface cache. Currently the + // cache is (size of main memory) / (surface cache size factor) KB + // or (surface cache max size) KB, whichever is smaller. The formula + // may change in the future, though. + // For example, a value of 4 would yield a 256MB cache on a 1GB machine. + // The smallest machines we are likely to run this code on have 256MB + // of memory, which would yield a 64MB cache on this setting. + // We clamp this value to avoid division by zero. + uint32_t surfaceCacheSizeFactor = + max(StaticPrefs::image_mem_surfacecache_size_factor_AtStartup(), 1u); + + // Compute the size of the surface cache. + uint64_t memorySize = PR_GetPhysicalMemorySize(); + if (memorySize == 0) { +#if !defined(__DragonFly__) + MOZ_ASSERT_UNREACHABLE("PR_GetPhysicalMemorySize not implemented here"); +#endif + memorySize = 256 * 1024 * 1024; // Fall back to 256MB. + } + uint64_t proposedSize = memorySize / surfaceCacheSizeFactor; + uint64_t surfaceCacheSizeBytes = + min(proposedSize, surfaceCacheMaxSizeKB * 1024); + uint32_t finalSurfaceCacheSizeBytes = + min(surfaceCacheSizeBytes, uint64_t(UINT32_MAX)); + + // Create the surface cache singleton with the requested settings. Note that + // the size is a limit that the cache may not grow beyond, but we do not + // actually allocate any storage for surfaces at this time. + sInstance = new SurfaceCacheImpl(surfaceCacheExpirationTimeMS, + surfaceCacheDiscardFactor, + finalSurfaceCacheSizeBytes); + sInstance->InitMemoryReporter(); +} + +/* static */ +void SurfaceCache::Shutdown() { + RefPtr<SurfaceCacheImpl> cache; + { + StaticMutexAutoLock lock(sInstanceMutex); + MOZ_ASSERT(NS_IsMainThread()); + MOZ_ASSERT(sInstance, "No singleton - was Shutdown() called twice?"); + cache = sInstance.forget(); + } +} + +/* static */ +LookupResult SurfaceCache::Lookup(const ImageKey aImageKey, + const SurfaceKey& aSurfaceKey, + bool aMarkUsed) { + nsTArray<RefPtr<CachedSurface>> discard; + LookupResult rv(MatchType::NOT_FOUND); + + { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return rv; + } + + rv = sInstance->Lookup(aImageKey, aSurfaceKey, lock, aMarkUsed); + sInstance->TakeDiscard(discard, lock); + } + + return rv; +} + +/* static */ +LookupResult SurfaceCache::LookupBestMatch(const ImageKey aImageKey, + const SurfaceKey& aSurfaceKey, + bool aMarkUsed) { + nsTArray<RefPtr<CachedSurface>> discard; + LookupResult rv(MatchType::NOT_FOUND); + + { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return rv; + } + + rv = sInstance->LookupBestMatch(aImageKey, aSurfaceKey, lock, aMarkUsed); + sInstance->TakeDiscard(discard, lock); + } + + return rv; +} + +/* static */ +InsertOutcome SurfaceCache::Insert(NotNull<ISurfaceProvider*> aProvider) { + nsTArray<RefPtr<CachedSurface>> discard; + InsertOutcome rv(InsertOutcome::FAILURE); + + { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return rv; + } + + rv = sInstance->Insert(aProvider, /* aSetAvailable = */ false, lock); + sInstance->TakeDiscard(discard, lock); + } + + return rv; +} + +/* static */ +bool SurfaceCache::CanHold(const IntSize& aSize, + uint32_t aBytesPerPixel /* = 4 */) { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return false; + } + + Cost cost = ComputeCost(aSize, aBytesPerPixel); + return sInstance->CanHold(cost); +} + +/* static */ +bool SurfaceCache::CanHold(size_t aSize) { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return false; + } + + return sInstance->CanHold(aSize); +} + +/* static */ +void SurfaceCache::SurfaceAvailable(NotNull<ISurfaceProvider*> aProvider) { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return; + } + + sInstance->SurfaceAvailable(aProvider, lock); +} + +/* static */ +void SurfaceCache::LockImage(const ImageKey aImageKey) { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + return sInstance->LockImage(aImageKey); + } +} + +/* static */ +void SurfaceCache::UnlockImage(const ImageKey aImageKey) { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + return sInstance->UnlockImage(aImageKey, lock); + } +} + +/* static */ +void SurfaceCache::UnlockEntries(const ImageKey aImageKey) { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + return sInstance->UnlockEntries(aImageKey, lock); + } +} + +/* static */ +void SurfaceCache::RemoveImage(const ImageKey aImageKey) { + RefPtr<ImageSurfaceCache> discard; + { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + discard = sInstance->RemoveImage(aImageKey, lock); + } + } +} + +/* static */ +void SurfaceCache::PruneImage(const ImageKey aImageKey) { + nsTArray<RefPtr<CachedSurface>> discard; + { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + sInstance->PruneImage(aImageKey, lock); + sInstance->TakeDiscard(discard, lock); + } + } +} + +/* static */ +bool SurfaceCache::InvalidateImage(const ImageKey aImageKey) { + nsTArray<RefPtr<CachedSurface>> discard; + bool rv = false; + { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + rv = sInstance->InvalidateImage(aImageKey, lock); + sInstance->TakeDiscard(discard, lock); + } + } + return rv; +} + +/* static */ +void SurfaceCache::DiscardAll() { + nsTArray<RefPtr<CachedSurface>> discard; + { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + sInstance->DiscardAll(lock); + sInstance->TakeDiscard(discard, lock); + } + } +} + +/* static */ +void SurfaceCache::ResetAnimation(const ImageKey aImageKey, + const SurfaceKey& aSurfaceKey) { + RefPtr<CachedSurface> surface; + nsTArray<RefPtr<CachedSurface>> discard; + { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return; + } + + surface = + sInstance->GetSurfaceForResetAnimation(aImageKey, aSurfaceKey, lock); + sInstance->TakeDiscard(discard, lock); + } + + // Calling Reset will acquire the AnimationSurfaceProvider::mFramesMutex + // mutex. In other places we acquire the mFramesMutex then call into the + // surface cache (acquiring the surface cache mutex), so that determines a + // lock order which we must obey by calling Reset after releasing the surface + // cache mutex. + if (surface) { + DrawableSurface drawableSurface = + surface->GetDrawableSurfaceEvenIfPlaceholder(); + if (drawableSurface) { + MOZ_ASSERT(surface->GetSurfaceKey() == aSurfaceKey, + "ResetAnimation() not returning an exact match?"); + + drawableSurface.Reset(); + } + } +} + +/* static */ +void SurfaceCache::CollectSizeOfSurfaces( + const ImageKey aImageKey, nsTArray<SurfaceMemoryCounter>& aCounters, + MallocSizeOf aMallocSizeOf) { + nsTArray<RefPtr<CachedSurface>> discard; + { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return; + } + + sInstance->CollectSizeOfSurfaces(aImageKey, aCounters, aMallocSizeOf, lock); + sInstance->TakeDiscard(discard, lock); + } +} + +/* static */ +size_t SurfaceCache::MaximumCapacity() { + StaticMutexAutoLock lock(sInstanceMutex); + if (!sInstance) { + return 0; + } + + return sInstance->MaximumCapacity(); +} + +/* static */ +bool SurfaceCache::IsLegalSize(const IntSize& aSize) { + // reject over-wide or over-tall images + const int32_t k64KLimit = 0x0000FFFF; + if (MOZ_UNLIKELY(aSize.width > k64KLimit || aSize.height > k64KLimit)) { + NS_WARNING("image too big"); + return false; + } + + // protect against invalid sizes + if (MOZ_UNLIKELY(aSize.height <= 0 || aSize.width <= 0)) { + return false; + } + + // check to make sure we don't overflow a 32-bit + CheckedInt32 requiredBytes = + CheckedInt32(aSize.width) * CheckedInt32(aSize.height) * 4; + if (MOZ_UNLIKELY(!requiredBytes.isValid())) { + NS_WARNING("width or height too large"); + return false; + } + const int32_t maxSize = StaticPrefs::image_mem_max_legal_imgframe_size_kb(); + if (MOZ_UNLIKELY(maxSize > 0 && requiredBytes.value() / 1024 > maxSize)) { + return false; + } + return true; +} + +IntSize SurfaceCache::ClampVectorSize(const IntSize& aSize) { + // If we exceed the maximum, we need to scale the size downwards to fit. + // It shouldn't get here if it is significantly larger because + // VectorImage::UseSurfaceCacheForSize should prevent us from requesting + // a rasterized version of a surface greater than 4x the maximum. + int32_t maxSizeKB = + StaticPrefs::image_cache_max_rasterized_svg_threshold_kb(); + if (maxSizeKB <= 0) { + return aSize; + } + + int64_t proposedKB = int64_t(aSize.width) * aSize.height / 256; + if (maxSizeKB >= proposedKB) { + return aSize; + } + + double scale = sqrt(double(maxSizeKB) / proposedKB); + return IntSize(int32_t(scale * aSize.width), int32_t(scale * aSize.height)); +} + +IntSize SurfaceCache::ClampSize(ImageKey aImageKey, const IntSize& aSize) { + if (aImageKey->GetType() != imgIContainer::TYPE_VECTOR) { + return aSize; + } + + return ClampVectorSize(aSize); +} + +/* static */ +void SurfaceCache::ReleaseImageOnMainThread( + already_AddRefed<image::Image> aImage, bool aAlwaysProxy) { + if (NS_IsMainThread() && !aAlwaysProxy) { + RefPtr<image::Image> image = std::move(aImage); + return; + } + + // Don't try to dispatch the release after shutdown, we'll just leak the + // runnable. + if (AppShutdown::IsInOrBeyond(ShutdownPhase::XPCOMShutdownFinal)) { + return; + } + + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + sInstance->ReleaseImageOnMainThread(std::move(aImage), lock); + } else { + NS_ReleaseOnMainThread("SurfaceCache::ReleaseImageOnMainThread", + std::move(aImage), /* aAlwaysProxy */ true); + } +} + +/* static */ +void SurfaceCache::ClearReleasingImages() { + MOZ_ASSERT(NS_IsMainThread()); + + nsTArray<RefPtr<image::Image>> images; + { + StaticMutexAutoLock lock(sInstanceMutex); + if (sInstance) { + sInstance->TakeReleasingImages(images, lock); + } + } +} + +} // namespace image +} // namespace mozilla |