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// Copyright 2019 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_CORE_LAYOUT_NG_INLINE_NG_DIRTY_LINES_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_INLINE_NG_DIRTY_LINES_H_
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/layout/layout_box.h"
#include "third_party/blink/renderer/core/layout/layout_inline.h"
#include "third_party/blink/renderer/core/layout/layout_text.h"
#include "third_party/blink/renderer/core/paint/ng/ng_paint_fragment.h"
namespace blink {
// This class computes dirty line boxes.
class CORE_EXPORT NGDirtyLines {
STACK_ALLOCATED();
public:
explicit NGDirtyLines(const NGPaintFragment* block_fragment)
: block_fragment_(block_fragment) {
DCHECK(block_fragment_);
}
// Call |Handle*| functions for each object by traversing the LayoutObject
// tree in pre-order DFS.
//
// They return |true| when a dirty line was found. Because only the first
// dirty line is relevant, no further calls are necessary.
bool HandleText(LayoutText* layout_text) {
if (layout_text->SelfNeedsLayout()) {
MarkLastFragment();
return true;
}
UpdateLastFragment(layout_text->FirstInlineFragment());
return false;
}
bool HandleInlineBox(LayoutInline* layout_inline) {
if (layout_inline->SelfNeedsLayout()) {
MarkLastFragment();
return true;
}
// Do not keep fragments of LayoutInline unless it's a leaf, because
// the last fragment of LayoutInline is not the previous fragment of its
// descendants.
if (UNLIKELY(!layout_inline->FirstChild()))
UpdateLastFragment(layout_inline->FirstInlineFragment());
return false;
}
bool HandleAtomicInline(LayoutBox* layout_box) {
if (layout_box->NeedsLayout()) {
MarkLastFragment();
return true;
}
UpdateLastFragment(layout_box->FirstInlineFragment());
return false;
}
bool HandleFloatingOrOutOfFlowPositioned(LayoutObject* layout_object) {
DCHECK(layout_object->IsFloatingOrOutOfFlowPositioned());
if (layout_object->NeedsLayout()) {
MarkLastFragment();
return true;
}
// Don't update last fragment. Floats and OOF are opaque.
return false;
}
// Mark the line box at the specified text offset dirty.
void MarkAtTextOffset(unsigned offset);
private:
void UpdateLastFragment(NGPaintFragment* fragment) {
if (fragment)
last_fragment_ = fragment;
}
// Mark the line box that contains |last_fragment_| dirty. If |last_fragment_|
// is |nullptr|, the first line box is marked as dirty.
void MarkLastFragment();
const NGPaintFragment* block_fragment_;
NGPaintFragment* last_fragment_ = nullptr;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_INLINE_NG_DIRTY_LINES_H_
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