/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#ifndef GrGradientBitmapCache_DEFINED
#define GrGradientBitmapCache_DEFINED

#include "SkBitmap.h"
#include "SkMutex.h"
#include "SkNoncopyable.h"
#include "GrColor.h"

class GrGradientBitmapCache : SkNoncopyable {
public:
    GrGradientBitmapCache(int maxEntries, int resolution);
    ~GrGradientBitmapCache();

    // Assumes colors are compatible with the specified alphaType (e.g. if it's premul then colors
    // are already premultiplied). Thread safe.
    void getGradient(const GrColor4f* colors, const SkScalar* positions, int count,
                     SkColorType colorType, SkAlphaType alphaType, SkBitmap* bitmap);

private:
    SkMutex fMutex;

    int fEntryCount;
    const int fMaxEntries;
    const int fResolution;

    struct Entry;
    mutable Entry*  fHead;
    mutable Entry*  fTail;

    inline Entry* release(Entry*) const;
    inline void attachToHead(Entry*) const;

    bool find(const void* buffer, size_t len, SkBitmap*) const;
    void add(const void* buffer, size_t len, const SkBitmap&);

    void fillGradient(const GrColor4f* colors, const SkScalar* positions, int count,
                      SkColorType colorType, SkBitmap* bitmap);

#ifdef SK_DEBUG
    void validate() const;
#else
    void validate() const {}
#endif

    class AutoValidate : SkNoncopyable {
    public:
        AutoValidate(const GrGradientBitmapCache* bc) : fBC(bc) { bc->validate(); }
        ~AutoValidate() { fBC->validate(); }
    private:
        const GrGradientBitmapCache* fBC;
    };
};

#endif