Delete sky/engine/core/fetch

sky/engine/core/fetch/MemoryCache.h

-/*
-    Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
-    Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
-    Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
-
-    This library is free software; you can redistribute it and/or
-    modify it under the terms of the GNU Library General Public
-    License as published by the Free Software Foundation; either
-    version 2 of the License, or (at your option) any later version.
-
-    This library is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-    Library General Public License for more details.
-
-    You should have received a copy of the GNU Library General Public License
-    along with this library; see the file COPYING.LIB.  If not, write to
-    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
-    Boston, MA 02110-1301, USA.
-
-    This class provides all functionality needed for loading images, style sheets and html
-    pages from the web. It has a memory cache for these objects.
-*/
-
-#ifndef SKY_ENGINE_CORE_FETCH_MEMORYCACHE_H_
-#define SKY_ENGINE_CORE_FETCH_MEMORYCACHE_H_
-
-#include "base/cancelable_callback.h"
-#include "sky/engine/core/fetch/Resource.h"
-#include "sky/engine/core/fetch/ResourcePtr.h"
-#include "sky/engine/public/platform/WebThread.h"
-#include "sky/engine/wtf/HashMap.h"
-#include "sky/engine/wtf/Noncopyable.h"
-#include "sky/engine/wtf/Vector.h"
-#include "sky/engine/wtf/text/StringHash.h"
-#include "sky/engine/wtf/text/WTFString.h"
-
-namespace blink  {
-
-class Resource;
-class ResourceFetcher;
-class KURL;
-class ExecutionContext;
-
-// This cache holds subresources used by Web pages: images, scripts, stylesheets, etc.
-
-// The cache keeps a flexible but bounded window of dead resources that grows/shrinks
-// depending on the live resource load. Here's an example of cache growth over time,
-// with a min dead resource capacity of 25% and a max dead resource capacity of 50%:
-
-//        |-----|                              Dead: -
-//        |----------|                         Live: +
-//      --|----------|                         Cache boundary: | (objects outside this mark have been evicted)
-//      --|----------++++++++++|
-// -------|-----+++++++++++++++|
-// -------|-----+++++++++++++++|+++++
-
-// Enable this macro to periodically log information about the memory cache.
-#undef MEMORY_CACHE_STATS
-
-// Determines the order in which CachedResources are evicted
-// from the decoded resources cache.
-enum MemoryCacheLiveResourcePriority {
-    MemoryCacheLiveResourcePriorityLow = 0,
-    MemoryCacheLiveResourcePriorityHigh,
-    MemoryCacheLiveResourcePriorityUnknown
-};
-
-enum UpdateReason {
-    UpdateForAccess,
-    UpdateForPropertyChange
-};
-
-// MemoryCacheEntry class is used only in MemoryCache class, but we don't make
-// MemoryCacheEntry class an inner class of MemoryCache because of dependency
-// from MemoryCacheLRUList.
-class MemoryCacheEntry final {
-public:
-    static PassOwnPtr<MemoryCacheEntry> create(Resource* resource) { return adoptPtr(new MemoryCacheEntry(resource)); }
-
-    ResourcePtr<Resource> m_resource;
-    bool m_inLiveDecodedResourcesList;
-    unsigned m_accessCount;
-    MemoryCacheLiveResourcePriority m_liveResourcePriority;
-    double m_lastDecodedAccessTime; // Used as a thrash guard
-
-    RawPtr<MemoryCacheEntry> m_previousInLiveResourcesList;
-    RawPtr<MemoryCacheEntry> m_nextInLiveResourcesList;
-    RawPtr<MemoryCacheEntry> m_previousInAllResourcesList;
-    RawPtr<MemoryCacheEntry> m_nextInAllResourcesList;
-
-private:
-    explicit MemoryCacheEntry(Resource* resource)
-        : m_resource(resource)
-        , m_inLiveDecodedResourcesList(false)
-        , m_accessCount(0)
-        , m_liveResourcePriority(MemoryCacheLiveResourcePriorityLow)
-        , m_lastDecodedAccessTime(0.0)
-        , m_previousInLiveResourcesList(nullptr)
-        , m_nextInLiveResourcesList(nullptr)
-        , m_previousInAllResourcesList(nullptr)
-        , m_nextInAllResourcesList(nullptr)
-    {
-    }
-};
-
-// MemoryCacheLRUList is used only in MemoryCache class, but we don't make
-// MemoryCacheLRUList an inner struct of MemoryCache because we can't define
-// VectorTraits for inner structs.
-struct MemoryCacheLRUList final {
-    ALLOW_ONLY_INLINE_ALLOCATION();
-public:
-    RawPtr<MemoryCacheEntry> m_head;
-    RawPtr<MemoryCacheEntry> m_tail;
-
-    MemoryCacheLRUList() : m_head(nullptr), m_tail(nullptr) { }
-};
-
-}
-
-WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(blink::MemoryCacheLRUList);
-
-namespace blink {
-
-class MemoryCache final {
-    WTF_MAKE_NONCOPYABLE(MemoryCache); WTF_MAKE_FAST_ALLOCATED;
-public:
-    static PassOwnPtr<MemoryCache> create();
-    ~MemoryCache();
-
-    struct TypeStatistic {
-        int count;
-        int size;
-        int liveSize;
-        int decodedSize;
-        int encodedSize;
-        int encodedSizeDuplicatedInDataURLs;
-        int purgeableSize;
-        int purgedSize;
-
-        TypeStatistic()
-            : count(0)
-            , size(0)
-            , liveSize(0)
-            , decodedSize(0)
-            , encodedSize(0)
-            , encodedSizeDuplicatedInDataURLs(0)
-            , purgeableSize(0)
-            , purgedSize(0)
-        {
-        }
-
-        void addResource(Resource*);
-    };
-
-    struct Statistics {
-        TypeStatistic images;
-        TypeStatistic cssStyleSheets;
-        TypeStatistic scripts;
-        TypeStatistic xslStyleSheets;
-        TypeStatistic fonts;
-        TypeStatistic other;
-    };
-
-    Resource* resourceForURL(const KURL&);
-
-    void add(Resource*);
-    void replace(Resource* newResource, Resource* oldResource);
-    void remove(Resource*);
-    bool contains(const Resource*) const;
-
-    static KURL removeFragmentIdentifierIfNeeded(const KURL& originalURL);
-
-    // Sets the cache's memory capacities, in bytes. These will hold only approximately,
-    // since the decoded cost of resources like scripts and stylesheets is not known.
-    //  - minDeadBytes: The maximum number of bytes that dead resources should consume when the cache is under pressure.
-    //  - maxDeadBytes: The maximum number of bytes that dead resources should consume when the cache is not under pressure.
-    //  - totalBytes: The maximum number of bytes that the cache should consume overall.
-    void setCapacities(size_t minDeadBytes, size_t maxDeadBytes, size_t totalBytes);
-    void setDelayBeforeLiveDecodedPrune(double seconds) { m_delayBeforeLiveDecodedPrune = seconds; }
-    void setMaxPruneDeferralDelay(double seconds) { m_maxPruneDeferralDelay = seconds; }
-
-    void evictResources();
-
-    void prune(Resource* justReleasedResource = 0);
-
-    // Called to adjust a resource's size, lru list position, and access count.
-    void update(Resource*, size_t oldSize, size_t newSize, bool wasAccessed = false);
-    void updateForAccess(Resource* resource) { update(resource, resource->size(), resource->size(), true); }
-    void updateDecodedResource(Resource*, UpdateReason, MemoryCacheLiveResourcePriority = MemoryCacheLiveResourcePriorityUnknown);
-
-    void makeLive(Resource*);
-    void makeDead(Resource*);
-
-    // This should be called when a Resource object is created.
-    void registerLiveResource(Resource&);
-    // This should be called when a Resource object becomes unnecesarry.
-    void unregisterLiveResource(Resource&);
-
-    static void removeURLFromCache(ExecutionContext*, const KURL&);
-
-    Statistics getStatistics();
-
-    size_t minDeadCapacity() const { return m_minDeadCapacity; }
-    size_t maxDeadCapacity() const { return m_maxDeadCapacity; }
-    size_t capacity() const { return m_capacity; }
-    size_t liveSize() const { return m_liveSize; }
-    size_t deadSize() const { return m_deadSize; }
-
-    // Exposed for testing
-    MemoryCacheLiveResourcePriority priority(Resource*) const;
-
-private:
-    MemoryCache();
-
-    MemoryCacheLRUList* lruListFor(unsigned accessCount, size_t);
-
-#ifdef MEMORY_CACHE_STATS
-    void dumpStats(Timer<MemoryCache>*);
-    void dumpLRULists(bool includeLive) const;
-#endif
-
-    // Calls to put the cached resource into and out of LRU lists.
-    void insertInLRUList(MemoryCacheEntry*, MemoryCacheLRUList*);
-    void removeFromLRUList(MemoryCacheEntry*, MemoryCacheLRUList*);
-
-    // Track decoded resources that are in the cache and referenced by a Web page.
-    void insertInLiveDecodedResourcesList(MemoryCacheEntry*);
-    void removeFromLiveDecodedResourcesList(MemoryCacheEntry*);
-
-    size_t liveCapacity() const;
-    size_t deadCapacity() const;
-
-    void pruneMicrotask();
-    // pruneDeadResources() - Flush decoded and encoded data from resources not referenced by Web pages.
-    // pruneLiveResources() - Flush decoded data from resources still referenced by Web pages.
-    void pruneDeadResources(); // Automatically decide how much to prune.
-    void pruneLiveResources();
-    void pruneNow(double currentTime);
-
-    bool evict(MemoryCacheEntry*);
-
-    bool prunePending() const { return !m_pendingPrune.IsCancelled(); }
-
-    static void removeURLFromCacheInternal(ExecutionContext*, const KURL&);
-
-    bool m_inPruneResources;
-    double m_maxPruneDeferralDelay;
-    double m_pruneTimeStamp;
-    double m_pruneFrameTimeStamp;
-
-    size_t m_capacity;
-    size_t m_minDeadCapacity;
-    size_t m_maxDeadCapacity;
-    size_t m_maxDeferredPruneDeadCapacity;
-    double m_delayBeforeLiveDecodedPrune;
-
-    size_t m_liveSize; // The number of bytes currently consumed by "live" resources in the cache.
-    size_t m_deadSize; // The number of bytes currently consumed by "dead" resources in the cache.
-
-    base::CancelableClosure m_pendingPrune;
-
-    // Size-adjusted and popularity-aware LRU list collection for cache objects. This collection can hold
-    // more resources than the cached resource map, since it can also hold "stale" multiple versions of objects that are
-    // waiting to die when the clients referencing them go away.
-    Vector<MemoryCacheLRUList, 32> m_allResources;
-
-    // Lists just for live resources with decoded data. Access to this list is based off of painting the resource.
-    // The lists are ordered by decode priority, with higher indices having higher priorities.
-    MemoryCacheLRUList m_liveDecodedResources[MemoryCacheLiveResourcePriorityHigh + 1];
-
-    // A URL-based map of all resources that are in the cache (including the freshest version of objects that are currently being
-    // referenced by a Web page).
-    typedef HashMap<String, OwnPtr<MemoryCacheEntry> > ResourceMap;
-    ResourceMap m_resources;
-
-    friend class MemoryCacheTest;
-#ifdef MEMORY_CACHE_STATS
-    Timer<MemoryCache> m_statsTimer;
-#endif
-};
-
-// Returns the global cache.
-MemoryCache* memoryCache();
-
-// Sets the global cache, used to swap in a test instance. Returns the old
-// MemoryCache object.
-PassOwnPtr<MemoryCache> replaceMemoryCacheForTesting(PassOwnPtr<MemoryCache>);
-
-}
-
-#endif  // SKY_ENGINE_CORE_FETCH_MEMORYCACHE_H_