Initial exclusion aware layout opportunities implementation

third_party/WebKit/Source/core/layout/ng/ng_constraint_space.h

 // Copyright 2016 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 NGConstraintSpace_h
 #define NGConstraintSpace_h
 
 #include "core/CoreExport.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/ng/ng_physical_constraint_space.h"
 #include "core/layout/ng/ng_writing_mode.h"
 #include "platform/heap/Handle.h"
 #include "wtf/text/WTFString.h"
+#include "wtf/Vector.h"
 
 namespace blink {
 
 class LayoutBox;
 class NGDerivedConstraintSpace;
 class NGFragment;
 class NGLayoutOpportunityIterator;
 
 // The NGConstraintSpace represents a set of constraints and available space
 // which a layout algorithm may produce a NGFragment within. It is a view on
@@ skipping 67 matching lines @@
 
   // If specified a layout should produce a Fragment which fragments at the
   // blockSize if possible.
   NGFragmentationType BlockFragmentationType() const;
 
   // Modifies constraint space to account for a placed fragment. Depending on
   // the shape of the fragment this will either modify the inline or block
   // size, or add an exclusion.
   void Subtract(const NGFragment*);
 
-  NGLayoutOpportunityIterator LayoutOpportunities(
+  NGLayoutOpportunityIterator* LayoutOpportunities(
       unsigned clear = NGClearNone,
       bool for_inline_or_bfc = false);
 
   DEFINE_INLINE_VIRTUAL_TRACE() { visitor->trace(physical_space_); }
 
   // The setters for the NGConstraintSpace should only be used when constructing
   // a derived NGConstraintSpace.
   void SetOverflowTriggersScrollbar(bool inlineTriggers, bool blockTriggers);
   void SetFixedSize(bool inlineFixed, bool blockFixed);
   void SetFragmentationType(NGFragmentationType);
 
   String toString() const;
 
  private:
   Member<NGPhysicalConstraintSpace> physical_space_;
   NGLogicalOffset offset_;
   NGLogicalSize size_;
   unsigned writing_mode_ : 3;
 };
 
-class CORE_EXPORT NGLayoutOpportunityIterator final {
+class CORE_EXPORT NGLayoutOpportunityIterator final
+    : public GarbageCollectedFinalized<NGLayoutOpportunityIterator> {
  public:
   NGLayoutOpportunityIterator(NGConstraintSpace* space,
                               unsigned clear,
-                              bool for_inline_or_bfc)
-      : constraint_space_(space),
-        clear_(clear),
-        for_inline_or_bfc_(for_inline_or_bfc) {}
+                              bool for_inline_or_bfc);
   ~NGLayoutOpportunityIterator() {}
 
   NGConstraintSpace* Next();
 
+  DEFINE_INLINE_VIRTUAL_TRACE() {
+    visitor->trace(constraint_space_);
+    visitor->trace(current_opportunities_);
+  }
+
  private:
-  Persistent<NGConstraintSpace> constraint_space_;
+  void computeForExclusion(unsigned index);
+  LayoutUnit heightForOpportunity(LayoutUnit left,
+                                  LayoutUnit top,
+                                  LayoutUnit right,
+                                  LayoutUnit bottom);
+  void addLayoutOpportunity(LayoutUnit left,
+                            LayoutUnit top,
+                            LayoutUnit right,
+                            LayoutUnit bottom);
+
+  Member<NGConstraintSpace> constraint_space_;
   unsigned clear_;
   bool for_inline_or_bfc_;
+  Vector<NGExclusion> filtered_exclusions_;
+  HeapVector<Member<NGConstraintSpace>> current_opportunities_;
+  unsigned current_exclusion_;

[ikilpatrick, 2016/09/06 23:09:40]

current_exclusion_idx_ ? up to you.

[eae, 2016/09/06 23:30:53]

I like that, changed.

 };
 
 inline std::ostream& operator<<(std::ostream& stream,
                                 const NGConstraintSpace& value) {
   return stream << value.toString();
 }
 
 }  // namespace blink
 
 #endif  // NGConstraintSpace_h