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// Copyright 2022 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_CORE_LAYOUT_FRAGMENT_REPEATER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_FRAGMENT_REPEATER_H_
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
namespace blink {
class LayoutBox;
class LayoutResult;
class PhysicalBoxFragment;
// Fragment tree mutator / cloner / repeater.
//
// This is needed in order to implement repeated content in block fragmentation
// (repeated table headers / footers, and also fixed-positioned elements when
// printing).
//
// On the layout side, we only lay out the element once, but pre-paint and paint
// require one unique fragment for each time it repeats, since we need one
// FragmentData object for each, each with its own global-ish paint offset.
class FragmentRepeater {
STACK_ALLOCATED();
public:
// When regular layout is complete, we will have the right number of cloned
// root fragments, but its child fragments have not yet been cloned. Do that
// now, and update break tokens accordingly.
static void DeepCloneRepeatableRoot(LayoutBox&);
private:
FragmentRepeater(bool is_first_clone, bool is_last_fragment)
: is_first_clone_(is_first_clone), is_last_fragment_(is_last_fragment) {}
// Deep-clone the subtree of an already shallowly cloned fragment. This will
// also create new break tokens inside, in order to set unique sequence
// numbers. The result is only usable by pre-paint / painting, not by actual
// layout.
void CloneChildFragments(const PhysicalBoxFragment& cloned_fragment);
const LayoutResult* Repeat(const LayoutResult& other);
const LayoutResult* GetClonableLayoutResult(
const LayoutBox& layout_box,
const PhysicalBoxFragment& fragment) const;
// True when at the first cloned fragment.
bool is_first_clone_;
// True when at the last container fragment. No outgoing "repeat" break tokens
// should be created then.
bool is_last_fragment_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_FRAGMENT_REPEATER_H_
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