/*

 * Copyright 2010 Google Inc.

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef SkStrikeCache_DEFINED

#define SkStrikeCache_DEFINED

#include <unordered_map>

#include <unordered_set>

#include "include/private/SkSpinlock.h"

#include "include/private/SkTemplates.h"

#include "src/core/SkDescriptor.h"

#include "src/core/SkScalerCache.h"

class SkTraceMemoryDump;

#ifndef SK_DEFAULT_FONT_CACHE_COUNT_LIMIT

    #define SK_DEFAULT_FONT_CACHE_COUNT_LIMIT   2048

#endif

#ifndef SK_DEFAULT_FONT_CACHE_LIMIT

    #define SK_DEFAULT_FONT_CACHE_LIMIT     (2 * 1024 * 1024)

#endif

///////////////////////////////////////////////////////////////////////////////

class SkStrikePinner {

public:

    virtual ~SkStrikePinner() = default;

    virtual bool canDelete() = 0;

};

class SkStrikeCache final : public SkStrikeForGPUCacheInterface {

public:

    SkStrikeCache() = default;

    class Strike final : public SkRefCnt, public SkStrikeForGPU {

    public:

        Strike(SkStrikeCache* strikeCache,

               const SkDescriptor& desc,

               std::unique_ptr<SkScalerContext> scaler,

               const SkFontMetrics* metrics,

               std::unique_ptr<SkStrikePinner> pinner)

                : fStrikeCache{strikeCache}

                , fScalerCache{desc, std::move(scaler), metrics}

                , fPinner{std::move(pinner)} {}

        SkGlyph* mergeGlyphAndImage(SkPackedGlyphID toID, const SkGlyph& from) {

            auto [glyph, increase] = fScalerCache.mergeGlyphAndImage(toID, from);

            this->updateDelta(increase);

            return glyph;

        }

        const SkPath* mergePath(SkGlyph* glyph, const SkPath* path) {

            auto [glyphPath, increase] = fScalerCache.mergePath(glyph, path);

            this->updateDelta(increase);

            return glyphPath;

        }

        SkScalerContext* getScalerContext() const {

            return fScalerCache.getScalerContext();

        }

        void findIntercepts(const SkScalar bounds[2], SkScalar scale, SkScalar xPos,

                            SkGlyph* glyph, SkScalar* array, int* count) {

            fScalerCache.findIntercepts(bounds, scale, xPos, glyph, array, count);

        }

        const SkFontMetrics& getFontMetrics() const {

            return fScalerCache.getFontMetrics();

        }

        SkSpan<const SkGlyph*> metrics(SkSpan<const SkGlyphID> glyphIDs,

                                       const SkGlyph* results[]) {

            auto [glyphs, increase] = fScalerCache.metrics(glyphIDs, results);

            this->updateDelta(increase);

            return glyphs;

        }

        SkSpan<const SkGlyph*> preparePaths(SkSpan<const SkGlyphID> glyphIDs,

                                            const SkGlyph* results[]) {

            auto [glyphs, increase] = fScalerCache.preparePaths(glyphIDs, results);

            this->updateDelta(increase);

            return glyphs;

        }

        SkSpan<const SkGlyph*> prepareImages(SkSpan<const SkPackedGlyphID> glyphIDs,

                                             const SkGlyph* results[]) {

            auto [glyphs, increase] = fScalerCache.prepareImages(glyphIDs, results);

            this->updateDelta(increase);

            return glyphs;

        }

        void prepareForDrawingMasksCPU(SkDrawableGlyphBuffer* drawables) {

            size_t increase = fScalerCache.prepareForDrawingMasksCPU(drawables);

            this->updateDelta(increase);

        }

        const SkGlyphPositionRoundingSpec& roundingSpec() const override {

            return fScalerCache.roundingSpec();

        }

        const SkDescriptor& getDescriptor() const override {

            return fScalerCache.getDescriptor();

        }

        void prepareForMaskDrawing(

                SkDrawableGlyphBuffer* drawbles, SkSourceGlyphBuffer* rejects) override {

            size_t increase = fScalerCache.prepareForMaskDrawing(drawbles, rejects);

            this->updateDelta(increase);

        }

        void prepareForSDFTDrawing(

                SkDrawableGlyphBuffer* drawbles, SkSourceGlyphBuffer* rejects) override {

            size_t increase = fScalerCache.prepareForSDFTDrawing(drawbles, rejects);

            this->updateDelta(increase);

        }

        void prepareForPathDrawing(

                SkDrawableGlyphBuffer* drawbles, SkSourceGlyphBuffer* rejects) override {

            size_t increase = fScalerCache.prepareForPathDrawing(drawbles, rejects);

            this->updateDelta(increase);

        }

        void onAboutToExitScope() override {

            this->unref();

        }

        void updateDelta(size_t increase);

        SkStrikeCache* const            fStrikeCache;

        Strike*                         fNext{nullptr};

        Strike*                         fPrev{nullptr};

        SkScalerCache                   fScalerCache;

        std::unique_ptr<SkStrikePinner> fPinner;

        size_t                          fMemoryUsed{sizeof(SkScalerCache)};

        bool                            fRemoved{false};

    };  // Strike

    static SkStrikeCache* GlobalStrikeCache();

    sk_sp<Strike> findStrike(const SkDescriptor& desc) SK_EXCLUDES(fLock);

    sk_sp<Strike> createStrike(

            const SkDescriptor& desc,

            std::unique_ptr<SkScalerContext> scaler,

            SkFontMetrics* maybeMetrics = nullptr,

            std::unique_ptr<SkStrikePinner> = nullptr) SK_EXCLUDES(fLock);

    sk_sp<Strike> findOrCreateStrike(

            const SkDescriptor& desc,

            const SkScalerContextEffects& effects,

            const SkTypeface& typeface) SK_EXCLUDES(fLock);

    SkScopedStrikeForGPU findOrCreateScopedStrike(

            const SkDescriptor& desc,

            const SkScalerContextEffects& effects,

            const SkTypeface& typeface) override SK_EXCLUDES(fLock);

    static void PurgeAll();

    static void Dump();

    // Dump memory usage statistics of all the attaches caches in the process using the

    // SkTraceMemoryDump interface.

    static void DumpMemoryStatistics(SkTraceMemoryDump* dump);

    void purgeAll() SK_EXCLUDES(fLock); // does not change budget

    int getCacheCountLimit() const SK_EXCLUDES(fLock);

    int setCacheCountLimit(int limit) SK_EXCLUDES(fLock);

    int getCacheCountUsed() const SK_EXCLUDES(fLock);

    size_t getCacheSizeLimit() const SK_EXCLUDES(fLock);

    size_t setCacheSizeLimit(size_t limit) SK_EXCLUDES(fLock);

    size_t getTotalMemoryUsed() const SK_EXCLUDES(fLock);

private:

    sk_sp<Strike> internalFindStrikeOrNull(const SkDescriptor& desc) SK_REQUIRES(fLock);

    sk_sp<Strike> internalCreateStrike(

            const SkDescriptor& desc,

            std::unique_ptr<SkScalerContext> scaler,

            SkFontMetrics* maybeMetrics = nullptr,

            std::unique_ptr<SkStrikePinner> = nullptr) SK_REQUIRES(fLock);

    // The following methods can only be called when mutex is already held.

    void internalRemoveStrike(Strike* strike) SK_REQUIRES(fLock);

    void internalAttachToHead(sk_sp<Strike> strike) SK_REQUIRES(fLock);

    // Checkout budgets, modulated by the specified min-bytes-needed-to-purge,

    // and attempt to purge caches to match.

    // Returns number of bytes freed.

    size_t internalPurge(size_t minBytesNeeded = 0) SK_REQUIRES(fLock);

    // A simple accounting of what each glyph cache reports and the strike cache total.

    void validate() const SK_REQUIRES(fLock);

    void forEachStrike(std::function<void(const Strike&)> visitor) const SK_EXCLUDES(fLock);

    mutable SkMutex fLock;

    Strike* fHead SK_GUARDED_BY(fLock) {nullptr};

    Strike* fTail SK_GUARDED_BY(fLock) {nullptr};

    struct StrikeTraits {

        static const SkDescriptor& GetKey(const sk_sp<Strike>& strike) {

            return strike->getDescriptor();

        }

        static uint32_t Hash(const SkDescriptor& descriptor) {

            return descriptor.getChecksum();

        }

    };

    SkTHashTable<sk_sp<Strike>, SkDescriptor, StrikeTraits> fStrikeLookup SK_GUARDED_BY(fLock);

    size_t  fCacheSizeLimit{SK_DEFAULT_FONT_CACHE_LIMIT};

    size_t  fTotalMemoryUsed SK_GUARDED_BY(fLock) {0};

    int32_t fCacheCountLimit{SK_DEFAULT_FONT_CACHE_COUNT_LIMIT};

    int32_t fCacheCount SK_GUARDED_BY(fLock) {0};

};

using SkStrike = SkStrikeCache::Strike;

#endif  // SkStrikeCache_DEFINED