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/*
* Copyright (C) 2013 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_DATA_CACHE_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_DATA_CACHE_H_
#include "third_party/blink/renderer/platform/fonts/font_platform_data.h"
#include "third_party/blink/renderer/platform/fonts/simple_font_data.h"
#include "third_party/blink/renderer/platform/wtf/hash_map.h"
#include "third_party/blink/renderer/platform/wtf/linked_hash_set.h"
namespace blink {
enum ShouldRetain { kRetain, kDoNotRetain };
enum PurgeSeverity { kPurgeIfNeeded, kForcePurge };
struct FontDataCacheKeyHash {
STATIC_ONLY(FontDataCacheKeyHash);
static unsigned GetHash(const FontPlatformData* platform_data) {
return platform_data->GetHash();
}
static bool Equal(const FontPlatformData* a, const FontPlatformData* b) {
const FontPlatformData* empty_value =
reinterpret_cast<FontPlatformData*>(-1);
if (a == empty_value)
return b == empty_value;
if (b == empty_value)
return a == empty_value;
if (!a || !b)
return a == b;
CHECK(a && b);
return *a == *b;
}
static const bool safe_to_compare_to_empty_or_deleted = true;
};
class FontDataCache {
USING_FAST_MALLOC(FontDataCache);
public:
FontDataCache() = default;
FontDataCache(const FontDataCache&) = delete;
FontDataCache& operator=(const FontDataCache&) = delete;
scoped_refptr<SimpleFontData> Get(const FontPlatformData*,
ShouldRetain = kRetain,
bool subpixel_ascent_descent = false);
bool Contains(const FontPlatformData*) const;
void Release(const SimpleFontData*);
// Purges items in FontDataCache according to provided severity.
// Returns true if any removal of cache items actually occurred.
bool Purge(PurgeSeverity);
private:
bool PurgeLeastRecentlyUsed(int count);
typedef HashMap<const FontPlatformData*,
std::pair<scoped_refptr<SimpleFontData>, unsigned>,
FontDataCacheKeyHash>
Cache;
Cache cache_;
LinkedHashSet<scoped_refptr<SimpleFontData>> inactive_font_data_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_DATA_CACHE_H_
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