| // Copyright 2017 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_NG_BLOCK_CHILD_ITERATOR_H_ |
| #define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_NG_BLOCK_CHILD_ITERATOR_H_ |
| |
| #include "third_party/blink/renderer/core/core_export.h" |
| #include "third_party/blink/renderer/core/layout/ng/ng_layout_input_node.h" |
| |
| namespace blink { |
| |
| class NGBreakToken; |
| class NGBlockBreakToken; |
| class NGInlineBreakToken; |
| |
| // A utility class for block-flow layout which given the first child and a |
| // break token will iterate through unfinished children. |
| // |
| // NextChild() is used to iterate through the children. This will be done in |
| // node order. If there are child break tokens, though, their nodes will be |
| // processed first, in break token order (which may or may not be the same as |
| // node order). When we're through those, we proceed to the next sibling node of |
| // that of the last break token - unless we have already seen and started all |
| // children (in which case the parent break token will be marked as such; |
| // |HasSeenAllChildren()| will return true). |
| // |
| // This class does not handle modifications to its arguments after it has been |
| // constructed. |
| class CORE_EXPORT NGBlockChildIterator { |
| STACK_ALLOCATED(); |
| |
| public: |
| NGBlockChildIterator(NGLayoutInputNode first_child, |
| const NGBlockBreakToken* break_token); |
| |
| // Returns the next input node which should be laid out, along with its |
| // respective break token. |
| // @param previous_inline_break_token The previous inline break token is |
| // needed as multiple line-boxes can exist within the same parent |
| // fragment, unlike blocks. |
| struct Entry; |
| Entry NextChild( |
| const NGInlineBreakToken* previous_inline_break_token = nullptr); |
| |
| // Return true if there are no more children to process. |
| bool IsAtEnd() const { return !child_; } |
| |
| private: |
| NGLayoutInputNode child_; |
| const NGBlockBreakToken* break_token_; |
| |
| // An index into break_token_'s ChildBreakTokens() vector. Used for keeping |
| // track of the next child break token to inspect. |
| wtf_size_t child_token_idx_; |
| }; |
| |
| struct NGBlockChildIterator::Entry { |
| STACK_ALLOCATED(); |
| |
| public: |
| Entry(NGLayoutInputNode node, const NGBreakToken* token) |
| : node(node), token(token) {} |
| |
| NGLayoutInputNode node; |
| const NGBreakToken* token; |
| |
| bool operator==(const NGBlockChildIterator::Entry& other) const { |
| return node == other.node && token == other.token; |
| } |
| }; |
| |
| } // namespace blink |
| |
| #endif // THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_NG_NG_BLOCK_CHILD_ITERATOR_H_ |