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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_FRAME_SHAPE_CACHE_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_FRAME_SHAPE_CACHE_H_
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_map.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/text/text_direction.h"
#include "third_party/blink/renderer/platform/wtf/text/string_hash.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
#include "third_party/blink/renderer/platform/wtf/vector_backed_linked_list.h"
#include "ui/gfx/geometry/rect_f.h"
namespace blink {
class PlainTextItem;
class PlainTextNode;
class ShapeResult;
// FrameShapeCache manages a cache for PlainTextNode, and a cache for
// ShapeResult and ink bounds. A PlainTextPainter instance owns multiple
// FrameShapeCache instances, and each FrameShapeCache instance is associated
// to a specific `Font`.
//
// The caches are aware of frames distinguished by DidSwitchFrame() calls. This
// allows the caches to purge old entries when the frame is switched.
class PLATFORM_EXPORT FrameShapeCache
: public GarbageCollected<FrameShapeCache> {
public:
FrameShapeCache();
void Trace(Visitor* visitor) const;
FrameShapeCache(const FrameShapeCache&) = delete;
FrameShapeCache& operator=(const FrameShapeCache&) = delete;
// This function should be called between the end of an animation frame and
// the beginning of the next animation frame.
void DidSwitchFrame();
// Cache entry for the PlainTextNode cache.
// Clients must not access `list_index`.
struct NodeEntry {
DISALLOW_NEW();
public:
// Cached data.
Member<PlainTextNode> node;
// A field for LRU management. It's kNotFound for entries created
// in the initial frame.
wtf_size_t list_index;
void Trace(Visitor* visitor) const;
};
// Find a PlainTextNode cache entry for the specified `text` and `direction`.
// If it's not found, new entry is created.
NodeEntry* FindOrCreateNodeEntry(const String& text, TextDirection direction);
// This should be called if FindOrCreateNodeEntry() didn't find an
// existing entry.
void RegisterNodeEntry(const String& text,
TextDirection direction,
PlainTextNode* node,
NodeEntry* entry);
// Cache entry for the ShapeResult cache.
// Clients must not access `list_index`.
struct ShapeEntry {
DISALLOW_NEW();
public:
// Cached data.
Member<const ShapeResult> shape_result;
gfx::RectF ink_bounds;
// A field for LRU management. It's kNotFound for entries created
// in the initial frame.
wtf_size_t list_index;
void Trace(Visitor* visitor) const;
};
// Find a ShapeResult cache entry for the specified `text` and `direction`.
// If it's not found, new entry is created.
ShapeEntry* FindOrCreateShapeEntry(const String& word,
TextDirection direction);
// This should be called if FindOrCreateShapeEntry() didn't find an
// existing entry.
void RegisterShapeEntry(const PlainTextItem& item, ShapeEntry* entry);
private:
using KeyType = std::pair<String, TextDirection>;
struct ListKey {
KeyType key;
uint32_t generation;
};
using LruList = VectorBackedLinkedList<ListKey>;
template <typename E>
E* FindOrCreateEntry(const String& text,
TextDirection direction,
HeapHashMap<KeyType, E>& map,
LruList& lru_list);
wtf_size_t ListIndexForNewEntry(const String& text,
TextDirection direction,
LruList& lru_list);
template <typename E>
void RemoveOldEntries(HeapHashMap<KeyType, E>& map, LruList& lru_list);
HeapHashMap<KeyType, NodeEntry> node_map_;
LruList node_lru_list_;
HeapHashMap<KeyType, ShapeEntry> shape_map_;
LruList shape_lru_list_;
static constexpr uint32_t kInitialFrame = 0;
uint32_t frame_generation_ = kInitialFrame;
// True if a cache has a new entry in the current frame.
bool added_new_entries_ = false;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_SHAPING_FRAME_SHAPE_CACHE_H_
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