Move canonicalPosition() for VisiblePosition to VisibleUnits.cpp

This patch moves |canonicalPosition()| for |VisiblePosition| to
"VisibleUnits.cpp" form "VisiblePosition.cpp" to make "VisiblePosition.cpp"
to simpler for improving code health and ease of templatizing |VisiblePosition|
class to introduce composed tree version.

This patch is a preparation of making selection to handle granularity for web
component, http://crrev.com/1277863002

BUG=513568
TEST=n/a; no behavior changes

Review URL: https://codereview.chromium.org/1314033005

git-svn-id: svn://svn.chromium.org/blink/trunk@201526 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -463,105 +463,10 @@ VisiblePosition honorEditingBoundaryAtOrAfter(const VisiblePosition& pos, const
     return firstEditableVisiblePositionAfterPositionInRoot(pos.deepEquivalent(), highestRoot);
 }
 
-template <typename PositionType>
-static PositionType canonicalizeCandidate(const PositionType& candidate)
-{
-    if (candidate.isNull())
-        return PositionType();
-    ASSERT(isVisuallyEquivalentCandidate(candidate));
-    PositionType upstream = mostBackwardCaretPosition(candidate);
-    if (isVisuallyEquivalentCandidate(upstream))
-        return upstream;
-    return candidate;
-}
-
-template <typename PositionType>
-static PositionType canonicalPosition(const PositionType& passedPosition)
-{
-    // Sometimes updating selection positions can be extremely expensive and occur
-    // frequently.  Often calling preventDefault on mousedown events can avoid
-    // doing unnecessary text selection work.  http://crbug.com/472258.
-    TRACE_EVENT0("blink", "VisiblePosition::canonicalPosition");
-
-    // The updateLayout call below can do so much that even the position passed
-    // in to us might get changed as a side effect. Specifically, there are code
-    // paths that pass selection endpoints, and updateLayout can change the selection.
-    PositionType position = passedPosition;
-
-    // FIXME (9535):  Canonicalizing to the leftmost candidate means that if we're at a line wrap, we will
-    // ask layoutObjects to paint downstream carets for other layoutObjects.
-    // To fix this, we need to either a) add code to all paintCarets to pass the responsibility off to
-    // the appropriate layoutObject for VisiblePosition's like these, or b) canonicalize to the rightmost candidate
-    // unless the affinity is upstream.
-    if (position.isNull())
-        return PositionType();
-
-    ASSERT(position.document());
-    position.document()->updateLayoutIgnorePendingStylesheets();
-
-    Node* node = position.computeContainerNode();
-
-    PositionType candidate = mostBackwardCaretPosition(position);
-    if (isVisuallyEquivalentCandidate(candidate))
-        return candidate;
-    candidate = mostForwardCaretPosition(position);
-    if (isVisuallyEquivalentCandidate(candidate))
-        return candidate;
-
-    // When neither upstream or downstream gets us to a candidate (upstream/downstream won't leave
-    // blocks or enter new ones), we search forward and backward until we find one.
-    PositionType next = canonicalizeCandidate(nextCandidate(position));
-    PositionType prev = canonicalizeCandidate(previousCandidate(position));
-    Node* nextNode = next.anchorNode();
-    Node* prevNode = prev.anchorNode();
-
-    // The new position must be in the same editable element. Enforce that first.
-    // Unless the descent is from a non-editable html element to an editable body.
-    if (isHTMLHtmlElement(node) && !node->hasEditableStyle() && node->document().body() && node->document().body()->hasEditableStyle())
-        return next.isNotNull() ? next : prev;
-
-    Element* editingRoot = editableRootForPosition(position);
-
-    // If the html element is editable, descending into its body will look like a descent
-    // from non-editable to editable content since rootEditableElement() always stops at the body.
-    if (isHTMLHtmlElement(editingRoot) || position.anchorNode()->isDocumentNode())
-        return next.isNotNull() ? next : prev;
-
-    bool prevIsInSameEditableElement = prevNode && editableRootForPosition(prev) == editingRoot;
-    bool nextIsInSameEditableElement = nextNode && editableRootForPosition(next) == editingRoot;
-    if (prevIsInSameEditableElement && !nextIsInSameEditableElement)
-        return prev;
-
-    if (nextIsInSameEditableElement && !prevIsInSameEditableElement)
-        return next;
-
-    if (!nextIsInSameEditableElement && !prevIsInSameEditableElement)
-        return PositionType();
-
-    // The new position should be in the same block flow element. Favor that.
-    Element* originalBlock = node ? enclosingBlockFlowElement(*node) : 0;
-    bool nextIsOutsideOriginalBlock = !nextNode->isDescendantOf(originalBlock) && nextNode != originalBlock;
-    bool prevIsOutsideOriginalBlock = !prevNode->isDescendantOf(originalBlock) && prevNode != originalBlock;
-    if (nextIsOutsideOriginalBlock && !prevIsOutsideOriginalBlock)
-        return prev;
-
-    return next;
-}
-
-Position canonicalPositionOf(const Position& position)
-{
-    return canonicalPosition(position);
-}
-
-PositionInComposedTree canonicalPositionOf(const PositionInComposedTree& position)
-{
-    return canonicalPosition(position);
-}
-
 template<typename Strategy>
 static PositionWithAffinityTemplate<Strategy> visiblePositionOfAlgorithm(const PositionAlgorithm<Strategy>& position, TextAffinity affinity)
 {
-    const PositionAlgorithm<Strategy> deepPosition = canonicalPosition(position);
+    const PositionAlgorithm<Strategy> deepPosition = canonicalPositionOf(position);
     if (deepPosition.isNull())
         return PositionWithAffinityTemplate<Strategy>();
     if (affinity == TextAffinity::Downstream)

third_party/WebKit/Source/core/editing/VisiblePosition.h

@@ -121,9 +121,6 @@ CORE_EXPORT IntRect absoluteCaretBoundsOf(const VisiblePosition&);
 VisiblePosition leftPositionOf(const VisiblePosition&);
 VisiblePosition rightPositionOf(const VisiblePosition&);
 
-CORE_EXPORT Position canonicalPositionOf(const Position&);
-CORE_EXPORT PositionInComposedTree canonicalPositionOf(const PositionInComposedTree&);
-
 // TODO(yosin) We should move |honorEditingBoundaryAtOr{Before,After} to
 // "VisibleUnits.cpp" as static function.
 // next() and previous() will increment/decrement by a character cluster.

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

@@ -6,6 +6,7 @@
 #include "core/editing/VisiblePosition.h"
 
 #include "core/editing/EditingTestBase.h"
+#include "core/editing/VisibleUnits.h"
 
 namespace blink {
 

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

@@ -66,6 +66,106 @@ namespace blink {
 using namespace HTMLNames;
 using namespace WTF::Unicode;
 
+template <typename PositionType>
+static PositionType canonicalizeCandidate(const PositionType& candidate)
+{
+    if (candidate.isNull())
+        return PositionType();
+    ASSERT(isVisuallyEquivalentCandidate(candidate));
+    PositionType upstream = mostBackwardCaretPosition(candidate);
+    if (isVisuallyEquivalentCandidate(upstream))
+        return upstream;
+    return candidate;
+}
+
+template <typename PositionType>
+static PositionType canonicalPosition(const PositionType& passedPosition)
+{
+    // Sometimes updating selection positions can be extremely expensive and
+    // occur frequently.  Often calling preventDefault on mousedown events can
+    // avoid doing unnecessary text selection work.  http://crbug.com/472258.
+    TRACE_EVENT0("blink", "VisiblePosition::canonicalPosition");
+
+    // The updateLayout call below can do so much that even the position passed
+    // in to us might get changed as a side effect. Specifically, there are code
+    // paths that pass selection endpoints, and updateLayout can change the
+    // selection.
+    PositionType position = passedPosition;
+
+    // FIXME (9535):  Canonicalizing to the leftmost candidate means that if
+    // we're at a line wrap, we will ask layoutObjects to paint downstream
+    // carets for other layoutObjects. To fix this, we need to either a) add
+    // code to all paintCarets to pass the responsibility off to the appropriate
+    // layoutObject for VisiblePosition's like these, or b) canonicalize to the
+    // rightmost candidate unless the affinity is upstream.
+    if (position.isNull())
+        return PositionType();
+
+    ASSERT(position.document());
+    position.document()->updateLayoutIgnorePendingStylesheets();
+
+    Node* node = position.computeContainerNode();
+
+    PositionType candidate = mostBackwardCaretPosition(position);
+    if (isVisuallyEquivalentCandidate(candidate))
+        return candidate;
+    candidate = mostForwardCaretPosition(position);
+    if (isVisuallyEquivalentCandidate(candidate))
+        return candidate;
+
+    // When neither upstream or downstream gets us to a candidate
+    // (upstream/downstream won't leave blocks or enter new ones), we search
+    // forward and backward until we find one.
+    PositionType next = canonicalizeCandidate(nextCandidate(position));
+    PositionType prev = canonicalizeCandidate(previousCandidate(position));
+    Node* nextNode = next.anchorNode();
+    Node* prevNode = prev.anchorNode();
+
+    // The new position must be in the same editable element. Enforce that
+    // first. Unless the descent is from a non-editable html element to an
+    // editable body.
+    if (isHTMLHtmlElement(node) && !node->hasEditableStyle() && node->document().body() && node->document().body()->hasEditableStyle())
+        return next.isNotNull() ? next : prev;
+
+    Element* editingRoot = editableRootForPosition(position);
+
+    // If the html element is editable, descending into its body will look like
+    // a descent from non-editable to editable content since
+    // |rootEditableElementOf()| always stops at the body.
+    if (isHTMLHtmlElement(editingRoot) || position.anchorNode()->isDocumentNode())
+        return next.isNotNull() ? next : prev;
+
+    bool prevIsInSameEditableElement = prevNode && editableRootForPosition(prev) == editingRoot;
+    bool nextIsInSameEditableElement = nextNode && editableRootForPosition(next) == editingRoot;
+    if (prevIsInSameEditableElement && !nextIsInSameEditableElement)
+        return prev;
+
+    if (nextIsInSameEditableElement && !prevIsInSameEditableElement)
+        return next;
+
+    if (!nextIsInSameEditableElement && !prevIsInSameEditableElement)
+        return PositionType();
+
+    // The new position should be in the same block flow element. Favor that.
+    Element* originalBlock = node ? enclosingBlockFlowElement(*node) : 0;
+    bool nextIsOutsideOriginalBlock = !nextNode->isDescendantOf(originalBlock) && nextNode != originalBlock;
+    bool prevIsOutsideOriginalBlock = !prevNode->isDescendantOf(originalBlock) && prevNode != originalBlock;
+    if (nextIsOutsideOriginalBlock && !prevIsOutsideOriginalBlock)
+        return prev;
+
+    return next;
+}
+
+Position canonicalPositionOf(const Position& position)
+{
+    return canonicalPosition(position);
+}
+
+PositionInComposedTree canonicalPositionOf(const PositionInComposedTree& position)
+{
+    return canonicalPosition(position);
+}
+
 static Node* previousLeafWithSameEditability(Node* node, EditableType editableType)
 {
     bool editable = node->hasEditableStyle(editableType);

third_party/WebKit/Source/core/editing/VisibleUnits.h

@@ -85,6 +85,9 @@ CORE_EXPORT PositionInComposedTree mostForwardCaretPosition(const PositionInComp
 CORE_EXPORT bool isVisuallyEquivalentCandidate(const Position&);
 CORE_EXPORT bool isVisuallyEquivalentCandidate(const PositionInComposedTree&);
 
+CORE_EXPORT Position canonicalPositionOf(const Position&);
+CORE_EXPORT PositionInComposedTree canonicalPositionOf(const PositionInComposedTree&);
+
 UChar32 characterAfter(const VisiblePosition&);
 UChar32 characterBefore(const VisiblePosition&);