GlyphDisplayListCache.h [plain text]
#pragma once
#include "DisplayList.h"
#include "FontCascade.h"
#include "Logging.h"
#include "TextRun.h"
#include <wtf/HashMap.h>
#include <wtf/MemoryPressureHandler.h>
#include <wtf/NeverDestroyed.h>
namespace WebCore {
template<typename LayoutRun>
class GlyphDisplayListCache {
public:
GlyphDisplayListCache() = default;
static GlyphDisplayListCache& singleton()
{
static NeverDestroyed<GlyphDisplayListCache> cache;
return cache;
}
DisplayList::DisplayList* get(const LayoutRun& run, const FontCascade& font, GraphicsContext& context, const TextRun& textRun)
{
if (MemoryPressureHandler::singleton().isUnderMemoryPressure()) {
if (!m_glyphRunMap.isEmpty()) {
LOG(MemoryPressure, "GlyphDisplayListCache::%s - Under memory pressure - size: %d - sizeInBytes: %ld", __FUNCTION__, size(), sizeInBytes());
clear();
}
return nullptr;
}
if (auto displayList = m_glyphRunMap.get(&run))
return displayList;
if (auto displayList = font.displayListForTextRun(context, textRun))
return m_glyphRunMap.add(&run, WTFMove(displayList)).iterator->value.get();
return nullptr;
}
void remove(const LayoutRun& run)
{
m_glyphRunMap.remove(&run);
}
void clear()
{
m_glyphRunMap.clear();
}
unsigned size() const
{
return m_glyphRunMap.size();
}
size_t sizeInBytes() const
{
size_t sizeInBytes = 0;
for (const auto& entry : m_glyphRunMap)
sizeInBytes += entry.value->sizeInBytes();
return sizeInBytes;
}
private:
using GlyphRunMap = HashMap<const LayoutRun*, std::unique_ptr<DisplayList::DisplayList>>;
GlyphRunMap m_glyphRunMap;
};
}