third_party/WebKit/Source/core/layout/SubtreeLayoutScope.h

   1 /*
   2  * Copyright (C) 2013 Google Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef SubtreeLayoutScope_h
  32 #define SubtreeLayoutScope_h
  33
  34 #include "core/inspector/InspectorTraceEvents.h"
  35 #include "wtf/Allocator.h"
  36 #include "wtf/HashSet.h"
  37
  38 // This is the way to mark a subtree as needing layout during layout,
  39 // e.g. for the purposes of doing a multipass layout.
  40 //
  41 // It should only be used during layout. Outside of layout, you should
  42 // just call layoutObject->setNeedsLayout() directly.
  43 //
  44 // It ensures that you don't accidentally mark part of the tree as
  45 // needing layout and not actually lay it out.
  46
  47 namespace blink {
  48
  49 class LayoutObject;
  50
  51 class SubtreeLayoutScope {
  52     STACK_ALLOCATED();
  53 public:
  54     SubtreeLayoutScope(LayoutObject& root);
  55     ~SubtreeLayoutScope();
  56
  57     void setNeedsLayout(LayoutObject* descendant, LayoutInvalidationReasonForTracing);
  58     void setChildNeedsLayout(LayoutObject* descendant);
  59
  60     LayoutObject& root() { return m_root; }
  61     void recordObjectMarkedForLayout(LayoutObject*);
  62
  63 private:
  64     LayoutObject& m_root;
  65
  66 #if ENABLE(ASSERT)
  67     HashSet<LayoutObject*> m_layoutObjectsToLayout;
  68 #endif
  69 };
  70
  71 }
  72
  73 #endif