[LayoutNG] Split LayoutOpportunityIterator into separate file

Split the LayoutOpportunityIterator class into separate source & header
files ng_layout_opportunity_iterator.h|cc from ng_constraint_space.h|cc

BUG=635619
TBR=glebl@chromium.org

Review-Url: https://codereview.chromium.org/2322293002
Cr-Commit-Position: refs/heads/master@{#417615}

third_party/WebKit/Source/core/layout/BUILD.gn

@@ -296,6 +296,8 @@ blink_core_sources("layout") {
     "ng/ng_fragment_builder.cc",
     "ng/ng_fragment_builder.h",
     "ng/ng_layout_input_text.h",
+    "ng/ng_layout_opportunity_iterator.cc",
+    "ng/ng_layout_opportunity_iterator.h",
     "ng/ng_length_utils.cc",
     "ng/ng_length_utils.h",
     "ng/ng_physical_constraint_space.cc",

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

@@ -6,9 +6,8 @@
 
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutView.h"
+#include "core/layout/ng/ng_layout_opportunity_iterator.h"
 #include "core/layout/ng/ng_units.h"
-#include "wtf/NonCopyingSort.h"
-#include <climits>
 
 namespace blink {
 
@@ -171,139 +170,4 @@ String NGConstraintSpace::toString() const {
                         size_.block_size.toString().ascii().data());
 }
 
-static inline bool AscendingTopCompare(const NGExclusion& a,
-                                       const NGExclusion& b) {
-  return a.Top() > b.Top();
-}
-
-NGLayoutOpportunityIterator::NGLayoutOpportunityIterator(
-    NGConstraintSpace* space,
-    unsigned clear,
-    bool for_inline_or_bfc)
-    : constraint_space_(space),
-      clear_(clear),
-      for_inline_or_bfc_(for_inline_or_bfc),
-      current_exclusion_idx_(0) {
-  for (const auto& item : constraint_space_->PhysicalSpace()->Exclusions())
-    filtered_exclusions_.append(item);
-
-  nonCopyingSort(filtered_exclusions_.begin(), filtered_exclusions_.end(),
-                 AscendingTopCompare);
-
-  // TODO(eae): Set based on offset.
-  LayoutUnit left;
-  LayoutUnit top;
-
-  unsigned i = filtered_exclusions_.size();
-  while (i--) {
-    const NGExclusion& exclusion = filtered_exclusions_[i];
-
-    // Remove items above OR to the left of the start offset as they have no
-    // effect on layout opportunities within this view.
-    if (exclusion.Right() <= left || exclusion.Bottom() <= top) {
-      filtered_exclusions_.remove(i);
-      continue;
-    }
-
-    // Remove items below AND to the right of the current exclusions as they're
-    // occluded and won't affect the layout opportunities.
-    for (unsigned j = filtered_exclusions_.size() - 1; j > i; j--) {
-      const NGExclusion& item = filtered_exclusions_[j];
-      if (item.Top() > exclusion.Top() && item.Left() > exclusion.Left())
-        filtered_exclusions_.remove(j);
-    }
-  }
-}
-
-NGConstraintSpace* NGLayoutOpportunityIterator::Next() {
-  if (current_opportunities_.isEmpty() &&
-      current_exclusion_idx_ < filtered_exclusions_.size()) {
-    computeForExclusion(current_exclusion_idx_);
-    current_exclusion_idx_++;
-  }
-
-  if (!current_opportunities_.isEmpty()) {
-    NGConstraintSpace* opportunity = current_opportunities_.last();
-    current_opportunities_.removeLast();
-    return opportunity;
-  }
-
-  if (filtered_exclusions_.isEmpty() && current_exclusion_idx_ == 0) {
-    current_exclusion_idx_++;
-    return new NGConstraintSpace(constraint_space_->WritingMode(),
-                                 constraint_space_->PhysicalSpace());
-  }
-
-  return nullptr;
-}
-
-static inline bool DescendingWidthCompare(const NGConstraintSpace* a,
-                                          const NGConstraintSpace* b) {
-  return a->Size().inline_size > b->Size().inline_size;
-}
-
-void NGLayoutOpportunityIterator::computeForExclusion(unsigned index) {
-  current_opportunities_.clear();
-
-  // TODO(eae): Set based on index.
-  LayoutUnit left;
-  LayoutUnit top;
-
-  // TODO(eae): Writing modes.
-  LayoutUnit right = constraint_space_->Size().inline_size;
-  LayoutUnit bottom = constraint_space_->Size().block_size;
-
-  // TODO(eae): Filter based on clear_ and for_inline_or_bfc_. Return early for
-  // now to make it clear neither are supported yet.
-  if (clear_ != NGClearNone || !for_inline_or_bfc_)
-    return;
-
-  // Compute opportunity for the full width from the start position to the right
-  // edge of the NGConstraintSpace.
-  LayoutUnit opportunityHeight = heightForOpportunity(left, top, right, bottom);
-  if (opportunityHeight && right > left)
-    addLayoutOpportunity(left, top, right - left, opportunityHeight);
-
-  // Compute the maximum available height between the current position and the
-  // left edge of each exclusion. The distance between the current horizontal
-  // position and the left edge of the exclusion determines the width of the
-  // opportunity.
-  for (const NGExclusion& exclusion : filtered_exclusions_) {
-    opportunityHeight =
-        heightForOpportunity(left, top, exclusion.Left(), bottom);
-    if (opportunityHeight && exclusion.Left() > left)
-      addLayoutOpportunity(left, top, exclusion.Left() - left,
-                           opportunityHeight);
-  }
-
-  nonCopyingSort(current_opportunities_.begin(), current_opportunities_.end(),
-                 DescendingWidthCompare);
-}
-
-// For the given 2D range (opportunity), this will return a height which makes
-// it bounded by the highest exclusion in the filtered exclusion list within the
-// range. Returns 0-height for an invalid opportunity (which has zero area).
-LayoutUnit NGLayoutOpportunityIterator::heightForOpportunity(
-    LayoutUnit left,
-    LayoutUnit top,
-    LayoutUnit right,
-    LayoutUnit bottom) {
-  LayoutUnit lowestBottom = bottom;
-  for (const NGExclusion& exclusion : filtered_exclusions_) {
-    if (exclusion.Left() < right && exclusion.Right() > left &&
-        exclusion.Bottom() > top && exclusion.Top() <= lowestBottom)
-      lowestBottom = exclusion.Top();
-  }
-  return std::max(lowestBottom - top, LayoutUnit());
-}
-
-void NGLayoutOpportunityIterator::addLayoutOpportunity(LayoutUnit left,
-                                                       LayoutUnit top,
-                                                       LayoutUnit right,
-                                                       LayoutUnit bottom) {
-  current_opportunities_.append(
-      new NGConstraintSpace(*constraint_space_, NGLogicalOffset(left, top),
-                            NGLogicalSize(right - left, bottom - top)));
-}
-
 }  // namespace blink

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

@@ -16,7 +16,6 @@
 namespace blink {
 
 class LayoutBox;
-class NGDerivedConstraintSpace;
 class NGFragment;
 class NGLayoutOpportunityIterator;
 
@@ -120,40 +119,6 @@ class CORE_EXPORT NGConstraintSpace final
   unsigned writing_mode_ : 3;
 };
 
-class CORE_EXPORT NGLayoutOpportunityIterator final
-    : public GarbageCollectedFinalized<NGLayoutOpportunityIterator> {
- public:
-  NGLayoutOpportunityIterator(NGConstraintSpace* space,
-                              unsigned clear,
-                              bool for_inline_or_bfc);
-  ~NGLayoutOpportunityIterator() {}
-
-  NGConstraintSpace* Next();
-
-  DEFINE_INLINE_VIRTUAL_TRACE() {
-    visitor->trace(constraint_space_);
-    visitor->trace(current_opportunities_);
-  }
-
- private:
-  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_idx_;
-};
-
 inline std::ostream& operator<<(std::ostream& stream,
                                 const NGConstraintSpace& value) {
   return stream << value.toString();

third_party/WebKit/Source/core/layout/ng/ng_constraint_space_test.cc

@@ -4,6 +4,7 @@
 
 #include "core/layout/ng/ng_constraint_space.h"
 
+#include "core/layout/ng/ng_layout_opportunity_iterator.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {

third_party/WebKit/Source/core/layout/ng/ng_layout_opportunity_iterator.cc

+// 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.
+
+#include "core/layout/ng/ng_layout_opportunity_iterator.h"
+
+#include "core/layout/ng/ng_physical_constraint_space.h"
+#include "core/layout/ng/ng_units.h"
+#include "wtf/NonCopyingSort.h"
+
+namespace blink {
+
+static inline bool AscendingTopCompare(const NGExclusion& a,
+                                       const NGExclusion& b) {
+  return a.Top() > b.Top();
+}
+
+NGLayoutOpportunityIterator::NGLayoutOpportunityIterator(
+    NGConstraintSpace* space,
+    unsigned clear,
+    bool for_inline_or_bfc)
+    : constraint_space_(space),
+      clear_(clear),
+      for_inline_or_bfc_(for_inline_or_bfc),
+      current_exclusion_idx_(0) {
+  for (const auto& item : constraint_space_->PhysicalSpace()->Exclusions())
+    filtered_exclusions_.append(item);
+
+  nonCopyingSort(filtered_exclusions_.begin(), filtered_exclusions_.end(),
+                 AscendingTopCompare);
+
+  // TODO(eae): Set based on offset.
+  LayoutUnit left;
+  LayoutUnit top;
+
+  unsigned i = filtered_exclusions_.size();
+  while (i--) {
+    const NGExclusion& exclusion = filtered_exclusions_[i];
+
+    // Remove items above OR to the left of the start offset as they have no
+    // effect on layout opportunities within this view.
+    if (exclusion.Right() <= left || exclusion.Bottom() <= top) {
+      filtered_exclusions_.remove(i);
+      continue;
+    }
+
+    // Remove items below AND to the right of the current exclusions as they're
+    // occluded and won't affect the layout opportunities.
+    for (unsigned j = filtered_exclusions_.size() - 1; j > i; j--) {
+      const NGExclusion& item = filtered_exclusions_[j];
+      if (item.Top() > exclusion.Top() && item.Left() > exclusion.Left())
+        filtered_exclusions_.remove(j);
+    }
+  }
+}
+
+NGConstraintSpace* NGLayoutOpportunityIterator::Next() {
+  if (current_opportunities_.isEmpty() &&
+      current_exclusion_idx_ < filtered_exclusions_.size()) {
+    computeForExclusion(current_exclusion_idx_);
+    current_exclusion_idx_++;
+  }
+
+  if (!current_opportunities_.isEmpty()) {
+    NGConstraintSpace* opportunity = current_opportunities_.last();
+    current_opportunities_.removeLast();
+    return opportunity;
+  }
+
+  if (filtered_exclusions_.isEmpty() && current_exclusion_idx_ == 0) {
+    current_exclusion_idx_++;
+    return new NGConstraintSpace(constraint_space_->WritingMode(),
+                                 constraint_space_->PhysicalSpace());
+  }
+
+  return nullptr;
+}
+
+static inline bool DescendingWidthCompare(const NGConstraintSpace* a,
+                                          const NGConstraintSpace* b) {
+  return a->Size().inline_size > b->Size().inline_size;
+}
+
+void NGLayoutOpportunityIterator::computeForExclusion(unsigned index) {
+  current_opportunities_.clear();
+
+  // TODO(eae): Set based on index.
+  LayoutUnit left;
+  LayoutUnit top;
+
+  // TODO(eae): Writing modes.
+  LayoutUnit right = constraint_space_->Size().inline_size;
+  LayoutUnit bottom = constraint_space_->Size().block_size;
+
+  // TODO(eae): Filter based on clear_ and for_inline_or_bfc_. Return early for
+  // now to make it clear neither are supported yet.
+  if (clear_ != NGClearNone || !for_inline_or_bfc_)
+    return;
+
+  // Compute opportunity for the full width from the start position to the right
+  // edge of the NGConstraintSpace.
+  LayoutUnit opportunityHeight = heightForOpportunity(left, top, right, bottom);
+  if (opportunityHeight && right > left)
+    addLayoutOpportunity(left, top, right - left, opportunityHeight);
+
+  // Compute the maximum available height between the current position and the
+  // left edge of each exclusion. The distance between the current horizontal
+  // position and the left edge of the exclusion determines the width of the
+  // opportunity.
+  for (const NGExclusion& exclusion : filtered_exclusions_) {
+    opportunityHeight =
+        heightForOpportunity(left, top, exclusion.Left(), bottom);
+    if (opportunityHeight && exclusion.Left() > left)
+      addLayoutOpportunity(left, top, exclusion.Left() - left,
+                           opportunityHeight);
+  }
+
+  nonCopyingSort(current_opportunities_.begin(), current_opportunities_.end(),
+                 DescendingWidthCompare);
+}
+
+// For the given 2D range (opportunity), this will return a height which makes
+// it bounded by the highest exclusion in the filtered exclusion list within the
+// range. Returns 0-height for an invalid opportunity (which has zero area).
+LayoutUnit NGLayoutOpportunityIterator::heightForOpportunity(
+    LayoutUnit left,
+    LayoutUnit top,
+    LayoutUnit right,
+    LayoutUnit bottom) {
+  LayoutUnit lowestBottom = bottom;
+  for (const NGExclusion& exclusion : filtered_exclusions_) {
+    if (exclusion.Left() < right && exclusion.Right() > left &&
+        exclusion.Bottom() > top && exclusion.Top() <= lowestBottom)
+      lowestBottom = exclusion.Top();
+  }
+  return std::max(lowestBottom - top, LayoutUnit());
+}
+
+void NGLayoutOpportunityIterator::addLayoutOpportunity(LayoutUnit left,
+                                                       LayoutUnit top,
+                                                       LayoutUnit right,
+                                                       LayoutUnit bottom) {
+  current_opportunities_.append(
+      new NGConstraintSpace(*constraint_space_, NGLogicalOffset(left, top),
+                            NGLogicalSize(right - left, bottom - top)));
+}
+
+}  // namespace blink

third_party/WebKit/Source/core/layout/ng/ng_layout_opportunity_iterator.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 NGLayoutOpportunityIterator_h
+#define NGLayoutOpportunityIterator_h
+
+#include "core/CoreExport.h"
+#include "core/layout/LayoutBox.h"
+#include "core/layout/ng/ng_constraint_space.h"
+#include "platform/heap/Handle.h"
+#include "wtf/text/WTFString.h"
+#include "wtf/Vector.h"
+
+namespace blink {
+
+class CORE_EXPORT NGLayoutOpportunityIterator final
+    : public GarbageCollectedFinalized<NGLayoutOpportunityIterator> {
+ public:
+  NGLayoutOpportunityIterator(NGConstraintSpace* space,
+                              unsigned clear,
+                              bool for_inline_or_bfc);
+  ~NGLayoutOpportunityIterator() {}
+
+  NGConstraintSpace* Next();
+
+  DEFINE_INLINE_VIRTUAL_TRACE() {
+    visitor->trace(constraint_space_);
+    visitor->trace(current_opportunities_);
+  }
+
+ private:
+  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_idx_;
+};
+
+}  // namespace blink
+
+#endif  // NGLayoutOpportunityIterator_h