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// Copyright 2015 The Chromium Authors. All rights reserved.
// 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_FONT_FALLBACK_ITERATOR_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_FALLBACK_ITERATOR_H_
#include "base/memory/scoped_refptr.h"
#include "third_party/blink/renderer/platform/fonts/font_data_for_range_set.h"
#include "third_party/blink/renderer/platform/fonts/font_fallback_priority.h"
#include "third_party/blink/renderer/platform/wtf/hash_map.h"
#include "third_party/blink/renderer/platform/wtf/ref_counted.h"
#include "third_party/blink/renderer/platform/wtf/text/unicode.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
namespace blink {
class FontDescription;
class FontFallbackList;
class SimpleFontData;
class FontFallbackIterator : public RefCounted<FontFallbackIterator> {
WTF_MAKE_NONCOPYABLE(FontFallbackIterator);
public:
static scoped_refptr<FontFallbackIterator> Create(const FontDescription&,
scoped_refptr<FontFallbackList>,
FontFallbackPriority);
bool HasNext() const { return fallback_stage_ != kOutOfLuck; };
// Some system fallback APIs (Windows, Android) require a character, or a
// portion of the string to be passed. On Mac and Linux, we get a list of
// fonts without passing in characters.
scoped_refptr<FontDataForRangeSet> Next(const Vector<UChar32>& hint_list);
private:
FontFallbackIterator(const FontDescription&,
scoped_refptr<FontFallbackList>,
FontFallbackPriority);
bool RangeSetContributesForHint(const Vector<UChar32> hint_list,
const FontDataForRangeSet*);
bool AlreadyLoadingRangeForHintChar(UChar32 hint_char);
void WillUseRange(const AtomicString& family, const FontDataForRangeSet&);
scoped_refptr<FontDataForRangeSet> UniqueOrNext(
scoped_refptr<FontDataForRangeSet> candidate,
const Vector<UChar32>& hint_list);
scoped_refptr<SimpleFontData> FallbackPriorityFont(UChar32 hint);
scoped_refptr<SimpleFontData> UniqueSystemFontForHintList(
const Vector<UChar32>& hint_list);
const FontDescription& font_description_;
scoped_refptr<FontFallbackList> font_fallback_list_;
int current_font_data_index_;
unsigned segmented_face_index_;
enum FallbackStage {
kFallbackPriorityFonts,
kFontGroupFonts,
kSegmentedFace,
kPreferencesFonts,
kSystemFonts,
kOutOfLuck
};
FallbackStage fallback_stage_;
HashSet<UChar32> previously_asked_for_hint_;
// FontFallbackIterator is meant for single use by HarfBuzzShaper,
// traversing through the fonts for shaping only once. We must not return
// duplicate FontDataForRangeSet objects from the next() iteration functions
// as returning a duplicate value causes a shaping run that won't return any
// results.
HashSet<uint32_t> unique_font_data_for_range_sets_returned_;
Vector<scoped_refptr<FontDataForRangeSet>> tracked_loading_range_sets_;
FontFallbackPriority font_fallback_priority_;
};
} // namespace blink
#endif
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