Move SelectionAdjust to its own file

third_party/WebKit/Source/core/editing/SelectionAdjuster.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.

[tkent, 2016/01/27 05:12:48]

Please use the copyright headers of SelectionEditor.cpp and
VisibleSelection.cpp.

[yosin_UTC9, 2016/01/27 05:58:22]

Done

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "core/editing/SelectionAdjuster.h"
+
+#include "core/editing/EditingUtilities.h"
+
+namespace blink {
+
+namespace {
+
+Node* enclosingShadowHost(Node* node)
+{
+    for (Node* runner = node; runner; runner = ComposedTreeTraversal::parent(*runner)) {
+        if (isShadowHost(runner))
+            return runner;
+    }
+    return nullptr;
+}
+
+bool isEnclosedBy(const PositionInComposedTree& position, const Node& node)
+{
+    ASSERT(position.isNotNull());
+    Node* anchorNode = position.anchorNode();
+    if (anchorNode == node)
+        return !position.isAfterAnchor() && !position.isBeforeAnchor();
+
+    return ComposedTreeTraversal::isDescendantOf(*anchorNode, node);
+}
+
+bool isSelectionBoundary(const Node& node)
+{
+    return isHTMLTextAreaElement(node) || isHTMLInputElement(node) || isHTMLSelectElement(node);
+}
+
+Node* enclosingShadowHostForStart(const PositionInComposedTree& position)
+{
+    Node* node = position.nodeAsRangeFirstNode();
+    if (!node)
+        return nullptr;
+    Node* shadowHost = enclosingShadowHost(node);
+    if (!shadowHost)
+        return nullptr;
+    if (!isEnclosedBy(position, *shadowHost))
+        return nullptr;
+    return isSelectionBoundary(*shadowHost) ? shadowHost : nullptr;
+}
+
+Node* enclosingShadowHostForEnd(const PositionInComposedTree& position)
+{
+    Node* node = position.nodeAsRangeLastNode();
+    if (!node)
+        return nullptr;
+    Node* shadowHost = enclosingShadowHost(node);
+    if (!shadowHost)
+        return nullptr;
+    if (!isEnclosedBy(position, *shadowHost))
+        return nullptr;
+    return isSelectionBoundary(*shadowHost) ? shadowHost : nullptr;
+}
+
+PositionInComposedTree adjustPositionInComposedTreeForStart(const PositionInComposedTree& position, Node* shadowHost)
+{
+    if (isEnclosedBy(position, *shadowHost)) {
+        if (position.isBeforeChildren())
+            return PositionInComposedTree::beforeNode(shadowHost);
+        return PositionInComposedTree::afterNode(shadowHost);
+    }
+
+    // We use |firstChild|'s after instead of beforeAllChildren for backward
+    // compatibility. The positions are same but the anchors would be different,
+    // and selection painting uses anchor nodes.
+    if (Node* firstChild = ComposedTreeTraversal::firstChild(*shadowHost))
+        return PositionInComposedTree::beforeNode(firstChild);
+    return PositionInComposedTree();
+}
+
+Position adjustPositionForEnd(const Position& currentPosition, Node* startContainerNode)
+{
+    TreeScope& treeScope = startContainerNode->treeScope();
+
+    ASSERT(currentPosition.computeContainerNode()->treeScope() != treeScope);
+
+    if (Node* ancestor = treeScope.ancestorInThisScope(currentPosition.computeContainerNode())) {
+        if (ancestor->contains(startContainerNode))
+            return positionAfterNode(ancestor);
+        return positionBeforeNode(ancestor);
+    }
+
+    if (Node* lastChild = treeScope.rootNode().lastChild())
+        return positionAfterNode(lastChild);
+
+    return Position();
+}
+
+PositionInComposedTree adjustPositionInComposedTreeForEnd(const PositionInComposedTree& position, Node* shadowHost)
+{
+    if (isEnclosedBy(position, *shadowHost)) {
+        if (position.isAfterChildren())
+            return PositionInComposedTree::afterNode(shadowHost);
+        return PositionInComposedTree::beforeNode(shadowHost);
+    }
+
+    // We use |lastChild|'s after instead of afterAllChildren for backward
+    // compatibility. The positions are same but the anchors would be different,
+    // and selection painting uses anchor nodes.
+    if (Node* lastChild = ComposedTreeTraversal::lastChild(*shadowHost))
+        return PositionInComposedTree::afterNode(lastChild);
+    return PositionInComposedTree();
+}
+
+Position adjustPositionForStart(const Position& currentPosition, Node* endContainerNode)
+{
+    TreeScope& treeScope = endContainerNode->treeScope();
+
+    ASSERT(currentPosition.computeContainerNode()->treeScope() != treeScope);
+
+    if (Node* ancestor = treeScope.ancestorInThisScope(currentPosition.computeContainerNode())) {
+        if (ancestor->contains(endContainerNode))
+            return positionBeforeNode(ancestor);
+        return positionAfterNode(ancestor);
+    }
+
+    if (Node* firstChild = treeScope.rootNode().firstChild())
+        return positionBeforeNode(firstChild);
+
+    return Position();
+}
+
+} // namespace
+
+// Updates |selectionInComposedTree| to match with |selection|.
+void SelectionAdjuster::adjustSelectionInComposedTree(VisibleSelectionInComposedTree* selectionInComposedTree, const VisibleSelection& selection)
+{
+    if (selection.isNone()) {
+        *selectionInComposedTree = VisibleSelectionInComposedTree();
+        return;
+    }
+
+    const PositionInComposedTree& base = toPositionInComposedTree(selection.base());
+    const PositionInComposedTree& extent = toPositionInComposedTree(selection.extent());
+    const PositionInComposedTree& position1 = toPositionInComposedTree(selection.start());
+    const PositionInComposedTree& position2 = toPositionInComposedTree(selection.end());
+    position1.anchorNode()->updateDistribution();
+    position2.anchorNode()->updateDistribution();
+    selectionInComposedTree->m_base = base;
+    selectionInComposedTree->m_extent = extent;
+    selectionInComposedTree->m_affinity = selection.m_affinity;
+    selectionInComposedTree->m_isDirectional = selection.m_isDirectional;
+    selectionInComposedTree->m_baseIsFirst = base.isNull() || base.compareTo(extent) <= 0;
+    if (position1.compareTo(position2) <= 0) {
+        selectionInComposedTree->m_start = position1;
+        selectionInComposedTree->m_end = position2;
+    } else {
+        selectionInComposedTree->m_start = position2;
+        selectionInComposedTree->m_end = position1;
+    }
+    selectionInComposedTree->updateSelectionType();
+}
+
+static bool isCrossingShadowBoundaries(const VisibleSelectionInComposedTree& selection)
+{
+    if (!selection.isRange())
+        return false;
+    TreeScope& treeScope = selection.base().anchorNode()->treeScope();
+    return selection.extent().anchorNode()->treeScope() != treeScope
+        || selection.start().anchorNode()->treeScope() != treeScope
+        || selection.end().anchorNode()->treeScope() != treeScope;
+}
+
+void SelectionAdjuster::adjustSelectionInDOMTree(VisibleSelection* selection, const VisibleSelectionInComposedTree& selectionInComposedTree)
+{
+    if (selectionInComposedTree.isNone()) {
+        *selection = VisibleSelection();
+        return;
+    }
+
+    const Position& base = toPositionInDOMTree(selectionInComposedTree.base());
+    const Position& extent = toPositionInDOMTree(selectionInComposedTree.extent());
+
+    if (isCrossingShadowBoundaries(selectionInComposedTree)) {
+        *selection = VisibleSelection(base, extent);
+        return;
+    }
+
+    const Position& position1 = toPositionInDOMTree(selectionInComposedTree.start());
+    const Position& position2 = toPositionInDOMTree(selectionInComposedTree.end());
+    selection->m_base = base;
+    selection->m_extent = extent;
+    selection->m_affinity = selectionInComposedTree.m_affinity;
+    selection->m_isDirectional = selectionInComposedTree.m_isDirectional;
+    selection->m_baseIsFirst = base.isNull() || base.compareTo(extent) <= 0;
+    if (position1.compareTo(position2) <= 0) {
+        selection->m_start = position1;
+        selection->m_end = position2;
+    } else {
+        selection->m_start = position2;
+        selection->m_end = position1;
+    }
+    selection->updateSelectionType();
+}
+
+void SelectionAdjuster::adjustSelectionToAvoidCrossingShadowBoundaries(VisibleSelection* selection)
+{
+    // Note: |m_selectionType| isn't computed yet.
+    ASSERT(selection->base().isNotNull());
+    ASSERT(selection->extent().isNotNull());
+    ASSERT(selection->start().isNotNull());
+    ASSERT(selection->end().isNotNull());
+
+    // TODO(hajimehoshi): Checking treeScope is wrong when a node is
+    // distributed, but we leave it as it is for backward compatibility.
+    if (selection->start().anchorNode()->treeScope() == selection->end().anchorNode()->treeScope())
+        return;
+
+    if (selection->isBaseFirst()) {
+        const Position& newEnd = adjustPositionForEnd(selection->end(), selection->start().computeContainerNode());
+        selection->m_extent = newEnd;
+        selection->m_end = newEnd;
+        return;
+    }
+
+    const Position& newStart = adjustPositionForStart(selection->start(), selection->end().computeContainerNode());
+    selection->m_extent = newStart;
+    selection->m_start = newStart;
+}
+
+// This function is called twice. The first is called when |m_start| and |m_end|
+// or |m_extent| are same, and the second when |m_start| and |m_end| are changed
+// after downstream/upstream.
+void SelectionAdjuster::adjustSelectionToAvoidCrossingShadowBoundaries(VisibleSelectionInComposedTree* selection)
+{
+    Node* const shadowHostStart = enclosingShadowHostForStart(selection->start());
+    Node* const shadowHostEnd = enclosingShadowHostForEnd(selection->end());
+    if (shadowHostStart == shadowHostEnd)
+        return;
+
+    if (selection->isBaseFirst()) {
+        Node* const shadowHost = shadowHostStart ? shadowHostStart : shadowHostEnd;
+        const PositionInComposedTree& newEnd = adjustPositionInComposedTreeForEnd(selection->end(), shadowHost);
+        selection->m_extent = newEnd;
+        selection->m_end = newEnd;
+        return;
+    }
+    Node* const shadowHost = shadowHostEnd ? shadowHostEnd : shadowHostStart;
+    const PositionInComposedTree& newStart = adjustPositionInComposedTreeForStart(selection->start(), shadowHost);
+    selection->m_extent = newStart;
+    selection->m_start = newStart;
+}
+
+} // namespace blink