Top down version of algorithm to position margins and floats in LayoutNG

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/ng/ng_units.h"
 #include "core/layout/ng/ng_writing_mode.h"
 #include "platform/heap/Handle.h"
+#include "wtf/Optional.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class LayoutBox;
 class NGBoxFragment;
 class NGLayoutOpportunityIterator;
 
-// TODO(glebl@): unused, delete.
-enum NGExclusionType {
-  kNGClearNone = 0,
-  kNGClearFloatLeft = 1,
-  kNGClearFloatRight = 2,
-  kNGClearFragment = 4
-};
-
 enum NGFragmentationType {
   kFragmentNone,
   kFragmentPage,
   kFragmentColumn,
   kFragmentRegion
 };
 
 // The NGConstraintSpace represents a set of constraints and available space
 // which a layout algorithm may produce a NGFragment within.
 class CORE_EXPORT NGConstraintSpace final
@@ skipping 20 matching lines @@
   // The size to use for percentage resolution.
   // See: https://drafts.csswg.org/css-sizing/#percentage-sizing
   NGLogicalSize PercentageResolutionSize() const {
     return percentage_resolution_size_;
   }
 
   // The available space size.
   // See: https://drafts.csswg.org/css-sizing/#available
   NGLogicalSize AvailableSize() const { return available_size_; }
 
-  // Offset relative to the root constraint space.
-  NGLogicalOffset Offset() const { return offset_; }
-  // TODO(layout-ng): Set offset via NGConstraintSpacebuilder.
-  void SetOffset(const NGLogicalOffset& offset) { offset_ = offset; }
-
   // Return the block-direction space available in the current fragmentainer.
   LayoutUnit FragmentainerSpaceAvailable() const {
     DCHECK(HasBlockFragmentation());
     return fragmentainer_space_available_;
   }
 
   // Whether the current constraint space is for the newly established
   // Formatting Context.
   bool IsNewFormattingContext() const { return is_new_fc_; }
 
@@ skipping 32 matching lines @@
   bool HasBlockFragmentation() const {
     return BlockFragmentationType() != kFragmentNone;
   }
 
   // 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 NGBoxFragment*);
 
   NGLayoutOpportunityIterator* LayoutOpportunities(
-      unsigned clear = kNGClearNone,
-      bool for_inline_or_bfc = false);
+      const WTF::Optional<NGLogicalOffset>& opt_origin_point = WTF::nullopt);
+
+  NGMarginStrut MarginStrut() const { return margin_strut_; }
+
+  NGLogicalOffset BfcOffset() const { return bfc_offset_; }
 
   DEFINE_INLINE_VIRTUAL_TRACE() {}
 
   String ToString() const;
 
  private:
   friend class NGConstraintSpaceBuilder;
   // Default constructor.
   NGConstraintSpace(NGWritingMode,
                     TextDirection,
                     NGLogicalSize available_size,
                     NGLogicalSize percentage_resolution_size,
                     LayoutUnit fragmentainer_space_available,
                     bool is_fixed_size_inline,
                     bool is_fixed_size_block,
                     bool is_shrink_to_fit,
                     bool is_inline_direction_triggers_scrollbar,
                     bool is_block_direction_triggers_scrollbar,
                     NGFragmentationType block_direction_fragmentation_type,
                     bool is_new_fc,
+                    const NGMarginStrut& margin_strut,
+                    const NGLogicalOffset& bfc_offset,
                     const std::shared_ptr<NGExclusions>& exclusions);
 
   NGLogicalSize available_size_;
   NGLogicalSize percentage_resolution_size_;
 
   LayoutUnit fragmentainer_space_available_;
 
   unsigned is_fixed_size_inline_ : 1;
   unsigned is_fixed_size_block_ : 1;
 
   unsigned is_shrink_to_fit_ : 1;
 
   unsigned is_inline_direction_triggers_scrollbar_ : 1;
   unsigned is_block_direction_triggers_scrollbar_ : 1;
 
   unsigned block_direction_fragmentation_type_ : 2;
 
   // Whether the current constraint space is for the newly established
   // formatting Context
   unsigned is_new_fc_ : 1;
 
-  NGLogicalOffset offset_;
   unsigned writing_mode_ : 3;
   unsigned direction_ : 1;
 
+  NGMarginStrut margin_strut_;
+  NGLogicalOffset bfc_offset_;
   const std::shared_ptr<NGExclusions> exclusions_;
 };
 
 inline std::ostream& operator<<(std::ostream& stream,
                                 const NGConstraintSpace& value) {
   return stream << value.ToString();
 }
 
 }  // namespace blink
 
 #endif  // NGConstraintSpace_h