1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/canvas/src/CanvasImageCache.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,207 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + * This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#include "CanvasImageCache.h"
1.10 +#include "nsIImageLoadingContent.h"
1.11 +#include "nsExpirationTracker.h"
1.12 +#include "imgIRequest.h"
1.13 +#include "mozilla/dom/Element.h"
1.14 +#include "nsTHashtable.h"
1.15 +#include "mozilla/dom/HTMLCanvasElement.h"
1.16 +#include "nsContentUtils.h"
1.17 +#include "mozilla/Preferences.h"
1.18 +#include "mozilla/gfx/2D.h"
1.19 +
1.20 +namespace mozilla {
1.21 +
1.22 +using namespace dom;
1.23 +using namespace gfx;
1.24 +
1.25 +struct ImageCacheKey {
1.26 + ImageCacheKey(Element* aImage, HTMLCanvasElement* aCanvas)
1.27 + : mImage(aImage), mCanvas(aCanvas) {}
1.28 + Element* mImage;
1.29 + HTMLCanvasElement* mCanvas;
1.30 +};
1.31 +
1.32 +struct ImageCacheEntryData {
1.33 + ImageCacheEntryData(const ImageCacheEntryData& aOther)
1.34 + : mImage(aOther.mImage)
1.35 + , mILC(aOther.mILC)
1.36 + , mCanvas(aOther.mCanvas)
1.37 + , mRequest(aOther.mRequest)
1.38 + , mSourceSurface(aOther.mSourceSurface)
1.39 + , mSize(aOther.mSize)
1.40 + {}
1.41 + ImageCacheEntryData(const ImageCacheKey& aKey)
1.42 + : mImage(aKey.mImage)
1.43 + , mILC(nullptr)
1.44 + , mCanvas(aKey.mCanvas)
1.45 + {}
1.46 +
1.47 + nsExpirationState* GetExpirationState() { return &mState; }
1.48 +
1.49 + size_t SizeInBytes() { return mSize.width * mSize.height * 4; }
1.50 +
1.51 + // Key
1.52 + nsRefPtr<Element> mImage;
1.53 + nsIImageLoadingContent* mILC;
1.54 + nsRefPtr<HTMLCanvasElement> mCanvas;
1.55 + // Value
1.56 + nsCOMPtr<imgIRequest> mRequest;
1.57 + RefPtr<SourceSurface> mSourceSurface;
1.58 + gfxIntSize mSize;
1.59 + nsExpirationState mState;
1.60 +};
1.61 +
1.62 +class ImageCacheEntry : public PLDHashEntryHdr {
1.63 +public:
1.64 + typedef ImageCacheKey KeyType;
1.65 + typedef const ImageCacheKey* KeyTypePointer;
1.66 +
1.67 + ImageCacheEntry(const KeyType *key) :
1.68 + mData(new ImageCacheEntryData(*key)) {}
1.69 + ImageCacheEntry(const ImageCacheEntry &toCopy) :
1.70 + mData(new ImageCacheEntryData(*toCopy.mData)) {}
1.71 + ~ImageCacheEntry() {}
1.72 +
1.73 + bool KeyEquals(KeyTypePointer key) const
1.74 + {
1.75 + return mData->mImage == key->mImage && mData->mCanvas == key->mCanvas;
1.76 + }
1.77 +
1.78 + static KeyTypePointer KeyToPointer(KeyType& key) { return &key; }
1.79 + static PLDHashNumber HashKey(KeyTypePointer key)
1.80 + {
1.81 + return HashGeneric(key->mImage, key->mCanvas);
1.82 + }
1.83 + enum { ALLOW_MEMMOVE = true };
1.84 +
1.85 + nsAutoPtr<ImageCacheEntryData> mData;
1.86 +};
1.87 +
1.88 +static bool sPrefsInitialized = false;
1.89 +static int32_t sCanvasImageCacheLimit = 0;
1.90 +
1.91 +class ImageCache MOZ_FINAL : public nsExpirationTracker<ImageCacheEntryData,4> {
1.92 +public:
1.93 + // We use 3 generations of 1 second each to get a 2-3 seconds timeout.
1.94 + enum { GENERATION_MS = 1000 };
1.95 + ImageCache()
1.96 + : nsExpirationTracker<ImageCacheEntryData,4>(GENERATION_MS)
1.97 + , mTotal(0)
1.98 + {
1.99 + if (!sPrefsInitialized) {
1.100 + sPrefsInitialized = true;
1.101 + Preferences::AddIntVarCache(&sCanvasImageCacheLimit, "canvas.image.cache.limit", 0);
1.102 + }
1.103 + }
1.104 + ~ImageCache() {
1.105 + AgeAllGenerations();
1.106 + }
1.107 +
1.108 + virtual void NotifyExpired(ImageCacheEntryData* aObject)
1.109 + {
1.110 + mTotal -= aObject->SizeInBytes();
1.111 + RemoveObject(aObject);
1.112 + // Deleting the entry will delete aObject since the entry owns aObject
1.113 + mCache.RemoveEntry(ImageCacheKey(aObject->mImage, aObject->mCanvas));
1.114 + }
1.115 +
1.116 + nsTHashtable<ImageCacheEntry> mCache;
1.117 + size_t mTotal;
1.118 +};
1.119 +
1.120 +static ImageCache* gImageCache = nullptr;
1.121 +
1.122 +class CanvasImageCacheShutdownObserver MOZ_FINAL : public nsIObserver
1.123 +{
1.124 +public:
1.125 + NS_DECL_ISUPPORTS
1.126 + NS_DECL_NSIOBSERVER
1.127 +};
1.128 +
1.129 +void
1.130 +CanvasImageCache::NotifyDrawImage(Element* aImage,
1.131 + HTMLCanvasElement* aCanvas,
1.132 + imgIRequest* aRequest,
1.133 + SourceSurface* aSource,
1.134 + const gfxIntSize& aSize)
1.135 +{
1.136 + if (!gImageCache) {
1.137 + gImageCache = new ImageCache();
1.138 + nsContentUtils::RegisterShutdownObserver(new CanvasImageCacheShutdownObserver());
1.139 + }
1.140 +
1.141 + ImageCacheEntry* entry = gImageCache->mCache.PutEntry(ImageCacheKey(aImage, aCanvas));
1.142 + if (entry) {
1.143 + if (entry->mData->mSourceSurface) {
1.144 + // We are overwriting an existing entry.
1.145 + gImageCache->mTotal -= entry->mData->SizeInBytes();
1.146 + gImageCache->RemoveObject(entry->mData);
1.147 + }
1.148 + gImageCache->AddObject(entry->mData);
1.149 +
1.150 + nsCOMPtr<nsIImageLoadingContent> ilc = do_QueryInterface(aImage);
1.151 + if (ilc) {
1.152 + ilc->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST,
1.153 + getter_AddRefs(entry->mData->mRequest));
1.154 + }
1.155 + entry->mData->mILC = ilc;
1.156 + entry->mData->mSourceSurface = aSource;
1.157 + entry->mData->mSize = aSize;
1.158 +
1.159 + gImageCache->mTotal += entry->mData->SizeInBytes();
1.160 + }
1.161 +
1.162 + if (!sCanvasImageCacheLimit)
1.163 + return;
1.164 +
1.165 + // Expire the image cache early if its larger than we want it to be.
1.166 + while (gImageCache->mTotal > size_t(sCanvasImageCacheLimit))
1.167 + gImageCache->AgeOneGeneration();
1.168 +}
1.169 +
1.170 +SourceSurface*
1.171 +CanvasImageCache::Lookup(Element* aImage,
1.172 + HTMLCanvasElement* aCanvas,
1.173 + gfxIntSize* aSize)
1.174 +{
1.175 + if (!gImageCache)
1.176 + return nullptr;
1.177 +
1.178 + ImageCacheEntry* entry = gImageCache->mCache.GetEntry(ImageCacheKey(aImage, aCanvas));
1.179 + if (!entry || !entry->mData->mILC)
1.180 + return nullptr;
1.181 +
1.182 + nsCOMPtr<imgIRequest> request;
1.183 + entry->mData->mILC->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST, getter_AddRefs(request));
1.184 + if (request != entry->mData->mRequest)
1.185 + return nullptr;
1.186 +
1.187 + gImageCache->MarkUsed(entry->mData);
1.188 +
1.189 + *aSize = entry->mData->mSize;
1.190 + return entry->mData->mSourceSurface;
1.191 +}
1.192 +
1.193 +NS_IMPL_ISUPPORTS(CanvasImageCacheShutdownObserver, nsIObserver)
1.194 +
1.195 +NS_IMETHODIMP
1.196 +CanvasImageCacheShutdownObserver::Observe(nsISupports *aSubject,
1.197 + const char *aTopic,
1.198 + const char16_t *aData)
1.199 +{
1.200 + if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
1.201 + delete gImageCache;
1.202 + gImageCache = nullptr;
1.203 +
1.204 + nsContentUtils::UnregisterShutdownObserver(this);
1.205 + }
1.206 +
1.207 + return NS_OK;
1.208 +}
1.209 +
1.210 +} // namespace mozilla
