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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef NGBreakToken_h | 5 #ifndef NGBreakToken_h |
6 #define NGBreakToken_h | 6 #define NGBreakToken_h |
7 | 7 |
8 #include "core/CoreExport.h" | 8 #include "core/CoreExport.h" |
9 #include "platform/heap/Handle.h" | 9 #include "platform/heap/Handle.h" |
10 | 10 |
11 namespace blink { | 11 namespace blink { |
12 | 12 |
13 class NGLayoutInputNode; | |
Gleb Lanbin
2017/02/15 19:21:39
can we just include NGLayoutInputNode?
https://goo
mstensho (USE GERRIT)
2017/02/15 21:25:38
Chromium style thankfully overrides this, though:
ikilpatrick
2017/02/16 17:01:30
We should try and push for keeping the forward dec
| |
14 | |
15 // A break token is a continuation token for layout. A single layout input node | |
16 // can have multiple fragments asssociated with it. | |
17 // | |
18 // Each fragment has a break token which can be used to determine if a layout | |
19 // input node has been "exhausted" of fragments, and optionally used to produce | |
20 // the next fragment in the chain. | |
21 // | |
22 // See CSS Fragmentation (https://drafts.csswg.org/css-break/) for a detailed | |
23 // description of different types of breaks which can occur in CSS. | |
24 // | |
25 // Each layout algorithm which can fragment, e.g. block-flow can optionally | |
26 // accept a break token. For example: | |
27 // | |
28 // NGLayoutInputNode* node = ...; | |
29 // NGPhysicalFragment* fragment = node->Layout(space); | |
30 // DCHECK(!fragment->BreakToken()->IsFinished()); | |
31 // NGPhysicalFragment* fragment2 = node->Layout(space, fragment->BreakToken()); | |
32 // | |
33 // The break token should encapsulate enough information to "resume" the layout. | |
13 class CORE_EXPORT NGBreakToken | 34 class CORE_EXPORT NGBreakToken |
14 : public GarbageCollectedFinalized<NGBreakToken> { | 35 : public GarbageCollectedFinalized<NGBreakToken> { |
15 public: | 36 public: |
16 virtual ~NGBreakToken() {} | 37 virtual ~NGBreakToken() {} |
17 | 38 |
18 enum NGBreakTokenType { kBlockBreakToken, kTextBreakToken }; | 39 enum NGBreakTokenType { kBlockBreakToken, kTextBreakToken }; |
19 NGBreakTokenType Type() const { return static_cast<NGBreakTokenType>(type_); } | 40 NGBreakTokenType Type() const { return static_cast<NGBreakTokenType>(type_); } |
20 | 41 |
21 DEFINE_INLINE_VIRTUAL_TRACE() {} | 42 // Whether the layout node cannot produce any more fragments. |
43 bool IsFinished() const { return is_finished_; } | |
Gleb Lanbin
2017/02/15 19:21:38
.nit you used "exhausted" word to explain this cas
ikilpatrick
2017/02/16 17:01:30
I'll keep as IsFinished, but reworded above...
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44 | |
45 // Returns the node associated with this break token. A break token cannot be | |
46 // used with any other node. | |
47 NGLayoutInputNode* InputNode() const { return node_.get(); } | |
Gleb Lanbin
2017/02/15 19:21:39
just return node_;
ikilpatrick
2017/02/16 17:01:30
Done.
| |
48 | |
49 DEFINE_INLINE_VIRTUAL_TRACE() { visitor->trace(node_); } | |
22 | 50 |
23 protected: | 51 protected: |
24 NGBreakToken(NGBreakTokenType type) : type_(type) {} | 52 NGBreakToken(NGBreakTokenType type, bool is_finished, NGLayoutInputNode* node) |
53 : type_(type), is_finished_(is_finished), node_(node) {} | |
25 | 54 |
26 private: | 55 private: |
27 unsigned type_ : 1; | 56 unsigned type_ : 1; |
57 unsigned is_finished_ : 1; | |
58 | |
59 Member<NGLayoutInputNode> node_; | |
28 }; | 60 }; |
29 | 61 |
30 } // namespace blink | 62 } // namespace blink |
31 | 63 |
32 #endif // NGBreakToken_h | 64 #endif // NGBreakToken_h |
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