[Reland] Refactor the selection code in EventHandler

Source/core/editing/SelectionController.cpp

Index: Source/core/editing/SelectionController.cpp
diff --git a/Source/core/editing/SelectionController.cpp b/Source/core/editing/SelectionController.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..c313530097fefcd66a2a380e2e60834a29d24a67
--- /dev/null
+++ b/Source/core/editing/SelectionController.cpp
@@ -0,0 +1,507 @@
+// Copyright 2015 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 "config.h"
+#include "core/editing/SelectionController.h"
+
+#include "core/HTMLNames.h"
+#include "core/dom/Document.h"
+#include "core/dom/DocumentMarkerController.h"
+#include "core/editing/Editor.h"
+#include "core/editing/FrameSelection.h"
+#include "core/editing/htmlediting.h"
+#include "core/editing/iterators/TextIterator.h"
+#include "core/events/Event.h"
+#include "core/frame/FrameView.h"
+#include "core/frame/LocalFrame.h"
+#include "core/frame/Settings.h"
+#include "core/layout/LayoutView.h"
+#include "core/page/FocusController.h"
+#include "core/page/Page.h"
+#include "platform/RuntimeEnabledFeatures.h"
+
+namespace blink {
+
+static void setSelectionIfNeeded(FrameSelection& selection, const VisibleSelection& newSelection)
+{
+    if (selection.selection() != newSelection)
+        selection.setSelection(newSelection);
+}
+
+static inline bool dispatchSelectStart(Node* node)
+{
+    if (!node || !node->layoutObject())
+        return true;
+
+    return node->dispatchEvent(Event::createCancelableBubble(EventTypeNames::selectstart));
+}
+
+static VisibleSelection expandSelectionToRespectUserSelectAll(Node* targetNode, const VisibleSelection& selection)
+{
+    Node* rootUserSelectAll = Position::rootUserSelectAllForNode(targetNode);
+    if (!rootUserSelectAll)
+        return selection;
+
+    VisibleSelection newSelection(selection);
+    newSelection.setBase(positionBeforeNode(rootUserSelectAll).upstream(CanCrossEditingBoundary));
+    newSelection.setExtent(positionAfterNode(rootUserSelectAll).downstream(CanCrossEditingBoundary));
+
+    return newSelection;
+}
+
+static inline bool canMouseDownStartSelect(Node* node)
+{
+    if (!node || !node->layoutObject())
+        return true;
+
+    if (!node->canStartSelection())
+        return false;
+
+    return true;
+}
+
+static int textDistance(const Position& start, const Position& end)
+{
+    RefPtrWillBeRawPtr<Range> range = Range::create(*start.document(), start, end);
+    return TextIterator::rangeLength(range->startPosition(), range->endPosition(), true);
+}
+
+SelectionController::SelectionController(LocalFrame* frame)
+    : m_frame(frame)
+    , m_allowSelection(false)
+    , m_singleClickInSelection(false)
+    , m_selectionState(HaveNotStartedSelection)
+{
+}
+
+void SelectionController::clear()
+{
+    m_allowSelection = false;
+    m_singleClickInSelection = false;
+    m_selectionState = HaveNotStartedSelection;
+
+}
+
+SelectionController::~SelectionController()
+{
+}
+
+bool SelectionController::updateSelectionForMouseDownDispatchingSelectStart(Node* targetNode, const VisibleSelection& selection, TextGranularity granularity)
+{
+    if (Position::nodeIsUserSelectNone(targetNode))
+        return false;
+
+    if (!dispatchSelectStart(targetNode))
+        return false;
+
+    if (selection.isRange()) {
+        m_selectionState = ExtendedSelection;
+    } else {
+        granularity = CharacterGranularity;
+        m_selectionState = PlacedCaret;
+    }
+
+    m_frame->selection().setNonDirectionalSelectionIfNeeded(selection, granularity);
+
+    return true;
+}
+
+void SelectionController::selectClosestWordFromHitTestResult(const HitTestResult& result, AppendTrailingWhitespace appendTrailingWhitespace)
+{
+    Node* innerNode = result.innerNode();
+    VisibleSelection newSelection;
+
+    if (innerNode && innerNode->layoutObject()) {
+        VisiblePosition pos(innerNode->layoutObject()->positionForPoint(result.localPoint()));
+        if (pos.isNotNull()) {
+            newSelection = VisibleSelection(pos);
+            newSelection.expandUsingGranularity(WordGranularity);
+        }
+
+        if (appendTrailingWhitespace == ShouldAppendTrailingWhitespace && newSelection.isRange())
+            newSelection.appendTrailingWhitespace();
+
+        updateSelectionForMouseDownDispatchingSelectStart(innerNode, expandSelectionToRespectUserSelectAll(innerNode, newSelection), WordGranularity);
+    }
+}
+
+void SelectionController::selectClosestMisspellingFromHitTestResult(const HitTestResult& result, AppendTrailingWhitespace appendTrailingWhitespace)
+{
+    Node* innerNode = result.innerNode();
+    VisibleSelection newSelection;
+
+    if (innerNode && innerNode->layoutObject()) {
+        VisiblePosition pos(innerNode->layoutObject()->positionForPoint(result.localPoint()));
+        Position start = pos.deepEquivalent();
+        Position end = pos.deepEquivalent();
+        if (pos.isNotNull()) {
+            DocumentMarkerVector markers = innerNode->document().markers().markersInRange(makeRange(pos, pos).get(), DocumentMarker::MisspellingMarkers());
+            if (markers.size() == 1) {
+                start.moveToOffset(markers[0]->startOffset());
+                end.moveToOffset(markers[0]->endOffset());
+                newSelection = VisibleSelection(start, end);
+            }
+        }
+
+        if (appendTrailingWhitespace == ShouldAppendTrailingWhitespace && newSelection.isRange())
+            newSelection.appendTrailingWhitespace();
+
+        updateSelectionForMouseDownDispatchingSelectStart(innerNode, expandSelectionToRespectUserSelectAll(innerNode, newSelection), WordGranularity);
+    }
+}
+
+void SelectionController::selectClosestWordFromMouseEvent(const MouseEventWithHitTestResults& result)
+{
+    if (m_allowSelection) {
+        selectClosestWordFromHitTestResult(result.hitTestResult(),
+            (result.event().clickCount() == 2 && m_frame->editor().isSelectTrailingWhitespaceEnabled()) ? ShouldAppendTrailingWhitespace : DontAppendTrailingWhitespace);
+    }
+}
+
+void SelectionController::selectClosestMisspellingFromMouseEvent(const MouseEventWithHitTestResults& result)
+{
+    if (m_allowSelection) {
+        selectClosestMisspellingFromHitTestResult(result.hitTestResult(),
+            (result.event().clickCount() == 2 && m_frame->editor().isSelectTrailingWhitespaceEnabled()) ? ShouldAppendTrailingWhitespace : DontAppendTrailingWhitespace);
+    }
+}
+
+void SelectionController::selectClosestWordOrLinkFromMouseEvent(const MouseEventWithHitTestResults& result)
+{
+    if (!result.hitTestResult().isLiveLink())
+        return selectClosestWordFromMouseEvent(result);
+
+    Node* innerNode = result.innerNode();
+
+    if (innerNode && innerNode->layoutObject() && m_allowSelection) {
+        VisibleSelection newSelection;
+        Element* URLElement = result.hitTestResult().URLElement();
+        VisiblePosition pos(innerNode->layoutObject()->positionForPoint(result.localPoint()));
+        if (pos.isNotNull() && pos.deepEquivalent().deprecatedNode()->isDescendantOf(URLElement))
+            newSelection = VisibleSelection::selectionFromContentsOfNode(URLElement);
+
+        updateSelectionForMouseDownDispatchingSelectStart(innerNode, expandSelectionToRespectUserSelectAll(innerNode, newSelection), WordGranularity);
+    }
+}
+
+void SelectionController::handleMousePressEvent(const MouseEventWithHitTestResults& event)
+{
+    // If we got the event back, that must mean it wasn't prevented,
+    // so it's allowed to start a drag or selection if it wasn't in a scrollbar.
+    m_allowSelection = canMouseDownStartSelect(event.innerNode()) && !event.scrollbar();
+    m_singleClickInSelection = false;
+}
+
+bool SelectionController::handleMousePressEventDoubleClick(const MouseEventWithHitTestResults& event)
+{
+    TRACE_EVENT0("blink", "EventHandler::handleMousePressEventDoubleClick");
+
+    if (event.event().button() != LeftButton)
+        return false;
+
+    if (m_frame->selection().isRange()) {
+        // A double-click when range is already selected
+        // should not change the selection.  So, do not call
+        // selectClosestWordFromMouseEvent, but do set
+        // m_beganSelectingText to prevent handleMouseReleaseEvent
+        // from setting caret selection.
+        m_selectionState = ExtendedSelection;
+    } else {
+        selectClosestWordFromMouseEvent(event);
+    }
+    return true;
+}
+
+bool SelectionController::handleMousePressEventTripleClick(const MouseEventWithHitTestResults& event)
+{
+    TRACE_EVENT0("blink", "EventHandler::handleMousePressEventTripleClick");
+
+    if (event.event().button() != LeftButton)
+        return false;
+
+    Node* innerNode = event.innerNode();
+    if (!(innerNode && innerNode->layoutObject() && m_allowSelection))
+        return false;
+
+    VisibleSelection newSelection;
+    VisiblePosition pos(innerNode->layoutObject()->positionForPoint(event.localPoint()));
+    if (pos.isNotNull()) {
+        newSelection = VisibleSelection(pos);
+        newSelection.expandUsingGranularity(ParagraphGranularity);
+    }
+
+    return updateSelectionForMouseDownDispatchingSelectStart(innerNode, expandSelectionToRespectUserSelectAll(innerNode, newSelection), ParagraphGranularity);
+}
+
+bool SelectionController::handleMousePressEventSingleClick(const MouseEventWithHitTestResults& event)
+{
+    TRACE_EVENT0("blink", "EventHandler::handleMousePressEventSingleClick");
+
+    m_frame->document()->updateLayoutIgnorePendingStylesheets();
+    Node* innerNode = event.innerNode();
+    if (!(innerNode && innerNode->layoutObject() && m_allowSelection))
+        return false;
+
+    // Extend the selection if the Shift key is down, unless the click is in a link.
+    bool extendSelection = event.event().shiftKey() && !event.isOverLink();
+
+    // Don't restart the selection when the mouse is pressed on an
+    // existing selection so we can allow for text dragging.
+    if (FrameView* view = m_frame->view()) {
+        LayoutPoint vPoint = view->rootFrameToContents(event.event().position());
+        if (!extendSelection && m_frame->selection().contains(vPoint)) {
+            m_singleClickInSelection = true;
+            return false;
+        }
+    }
+
+    VisiblePosition visiblePos(innerNode->layoutObject()->positionForPoint(event.localPoint()));
+    if (visiblePos.isNull())
+        visiblePos = VisiblePosition(firstPositionInOrBeforeNode(innerNode), DOWNSTREAM);
+    Position pos = visiblePos.deepEquivalent();
+
+    VisibleSelection newSelection = m_frame->selection().selection();
+    TextGranularity granularity = CharacterGranularity;
+
+    if (extendSelection && newSelection.isCaretOrRange()) {
+        VisibleSelection selectionInUserSelectAll(expandSelectionToRespectUserSelectAll(innerNode, VisibleSelection(VisiblePosition(pos))));
+        if (selectionInUserSelectAll.isRange()) {
+            if (comparePositions(selectionInUserSelectAll.start(), newSelection.start()) < 0)
+                pos = selectionInUserSelectAll.start();
+            else if (comparePositions(newSelection.end(), selectionInUserSelectAll.end()) < 0)
+                pos = selectionInUserSelectAll.end();
+        }
+
+        if (!m_frame->editor().behavior().shouldConsiderSelectionAsDirectional()) {
+            if (pos.isNotNull()) {
+                // See <rdar://problem/3668157> REGRESSION (Mail): shift-click deselects when selection
+                // was created right-to-left
+                Position start = newSelection.start();
+                Position end = newSelection.end();
+                int distanceToStart = textDistance(start, pos);
+                int distanceToEnd = textDistance(pos, end);
+                if (distanceToStart <= distanceToEnd)
+                    newSelection = VisibleSelection(end, pos);
+                else
+                    newSelection = VisibleSelection(start, pos);
+            }
+        } else {
+            newSelection.setExtent(pos);
+        }
+
+        if (m_frame->selection().granularity() != CharacterGranularity) {
+            granularity = m_frame->selection().granularity();
+            newSelection.expandUsingGranularity(m_frame->selection().granularity());
+        }
+    } else if (m_selectionState != ExtendedSelection) {
+        newSelection = expandSelectionToRespectUserSelectAll(innerNode, VisibleSelection(visiblePos));
+    }
+
+    // Updating the selection is considered side-effect of the event and so it doesn't impact the handled state.
+    updateSelectionForMouseDownDispatchingSelectStart(innerNode, newSelection, granularity);
+    return false;
+}
+
+void SelectionController::handleMouseDraggedEvent(const MouseEventWithHitTestResults& event, const IntPoint& mouseDownPos, const LayoutPoint& dragStartPos, const RefPtr<Node> mousePressNode, const IntPoint& lastKnownMousePosition)
+{
+    if (m_selectionState != ExtendedSelection) {
+        HitTestRequest request(HitTestRequest::ReadOnly | HitTestRequest::Active);
+        HitTestResult result(request, mouseDownPos);
+        m_frame->document()->layoutView()->hitTest(result);
+
+        updateSelectionForMouseDrag(result, mousePressNode, dragStartPos, lastKnownMousePosition);
+    }
+    updateSelectionForMouseDrag(event.hitTestResult(), mousePressNode, dragStartPos, lastKnownMousePosition);
+}
+
+bool SelectionController::handleMouseReleaseEvent(const MouseEventWithHitTestResults& event, const LayoutPoint& dragStartPos)
+{
+    bool handled = false;
+    m_allowSelection = false;
+    // Clear the selection if the mouse didn't move after the last mouse
+    // press and it's not a context menu click.  We do this so when clicking
+    // on the selection, the selection goes away.  However, if we are
+    // editing, place the caret.
+    if (m_singleClickInSelection && m_selectionState != ExtendedSelection
+        && dragStartPos == event.event().position()
+        && m_frame->selection().isRange()
+        && event.event().button() != RightButton) {
+        VisibleSelection newSelection;
+        Node* node = event.innerNode();
+        bool caretBrowsing = m_frame->settings() && m_frame->settings()->caretBrowsingEnabled();
+        if (node && node->layoutObject() && (caretBrowsing || node->hasEditableStyle())) {
+            VisiblePosition pos = VisiblePosition(node->layoutObject()->positionForPoint(event.localPoint()));
+            newSelection = VisibleSelection(pos);
+        }
+
+        setSelectionIfNeeded(m_frame->selection(), newSelection);
+
+        handled = true;
+    }
+
+    m_frame->selection().notifyRendererOfSelectionChange(UserTriggered);
+
+    m_frame->selection().selectFrameElementInParentIfFullySelected();
+
+    if (event.event().button() == MiddleButton && !event.isOverLink()) {
+        // Ignore handled, since we want to paste to where the caret was placed anyway.
+        handled = handlePasteGlobalSelection(event.event()) || handled;
+    }
+
+    return handled;
+}
+
+bool SelectionController::handlePasteGlobalSelection(const PlatformMouseEvent& mouseEvent)
+{
+    // If the event was a middle click, attempt to copy global selection in after
+    // the newly set caret position.
+    //
+    // This code is called from either the mouse up or mouse down handling. There
+    // is some debate about when the global selection is pasted:
+    //   xterm: pastes on up.
+    //   GTK: pastes on down.
+    //   Qt: pastes on up.
+    //   Firefox: pastes on up.
+    //   Chromium: pastes on up.
+    //
+    // There is something of a webcompat angle to this well, as highlighted by
+    // crbug.com/14608. Pages can clear text boxes 'onclick' and, if we paste on
+    // down then the text is pasted just before the onclick handler runs and
+    // clears the text box. So it's important this happens after the event
+    // handlers have been fired.
+    if (mouseEvent.type() != PlatformEvent::MouseReleased)
+        return false;
+
+    if (!m_frame->page())
+        return false;
+    Frame* focusFrame = m_frame->page()->focusController().focusedOrMainFrame();
+    // Do not paste here if the focus was moved somewhere else.
+    if (m_frame == focusFrame && m_frame->editor().behavior().supportsGlobalSelection())
+        return m_frame->editor().command("PasteGlobalSelection").execute();
+
+    return false;
+}
+
+void SelectionController::updateSelectionForMouseDrag(const RefPtr<Node> mousePressNode, const LayoutPoint& dragStartPos, const IntPoint& lastKnownMousePosition)
+{
+    FrameView* view = m_frame->view();
+    if (!view)
+        return;
+    LayoutView* renderer = m_frame->contentRenderer();
+    if (!renderer)
+        return;
+
+    HitTestRequest request(HitTestRequest::ReadOnly | HitTestRequest::Active | HitTestRequest::Move);
+    HitTestResult result(request, view->rootFrameToContents(lastKnownMousePosition));
+    renderer->hitTest(result);
+    updateSelectionForMouseDrag(result, mousePressNode, dragStartPos, lastKnownMousePosition);
+}
+
+void SelectionController::updateSelectionForMouseDrag(const HitTestResult& hitTestResult, const RefPtr<Node> mousePressNode, const LayoutPoint& dragStartPos, const IntPoint& lastKnownMousePosition)
+{
+    if (!m_allowSelection)
+        return;
+
+    Node* target = hitTestResult.innerNode();
+    if (!target)
+        return;
+
+    VisiblePosition targetPosition = m_frame->selection().selection().visiblePositionRespectingEditingBoundary(hitTestResult.localPoint(), target);
+    // Don't modify the selection if we're not on a node.
+    if (targetPosition.isNull())
+        return;
+
+    // Restart the selection if this is the first mouse move. This work is usually
+    // done in handleMousePressEvent, but not if the mouse press was on an existing selection.
+    VisibleSelection newSelection = m_frame->selection().selection();
+
+    // Special case to limit selection to the containing block for SVG text.
+    // FIXME: Isn't there a better non-SVG-specific way to do this?
+    if (Node* selectionBaseNode = newSelection.base().deprecatedNode()) {
+        if (LayoutObject* selectionBaseRenderer = selectionBaseNode->layoutObject()) {
+            if (selectionBaseRenderer->isSVGText()) {
+                if (target->layoutObject()->containingBlock() != selectionBaseRenderer->containingBlock())
+                    return;
+            }
+        }
+    }
+
+    if (m_selectionState == HaveNotStartedSelection && !dispatchSelectStart(target))
+        return;
+
+    if (m_selectionState != ExtendedSelection) {
+        // Always extend selection here because it's caused by a mouse drag
+        m_selectionState = ExtendedSelection;
+        newSelection = VisibleSelection(targetPosition);
+    }
+
+    if (RuntimeEnabledFeatures::userSelectAllEnabled()) {
+        Node* rootUserSelectAllForMousePressNode = Position::rootUserSelectAllForNode(mousePressNode.get());
+        if (rootUserSelectAllForMousePressNode && rootUserSelectAllForMousePressNode == Position::rootUserSelectAllForNode(target)) {
+            newSelection.setBase(positionBeforeNode(rootUserSelectAllForMousePressNode).upstream(CanCrossEditingBoundary));
+            newSelection.setExtent(positionAfterNode(rootUserSelectAllForMousePressNode).downstream(CanCrossEditingBoundary));
+        } else {
+            // Reset base for user select all when base is inside user-select-all area and extent < base.
+            if (rootUserSelectAllForMousePressNode && comparePositions(target->layoutObject()->positionForPoint(hitTestResult.localPoint()), mousePressNode->layoutObject()->positionForPoint(dragStartPos)) < 0)
+                newSelection.setBase(positionAfterNode(rootUserSelectAllForMousePressNode).downstream(CanCrossEditingBoundary));
+
+            Node* rootUserSelectAllForTarget = Position::rootUserSelectAllForNode(target);
+            if (rootUserSelectAllForTarget && mousePressNode->layoutObject() && comparePositions(target->layoutObject()->positionForPoint(hitTestResult.localPoint()), mousePressNode->layoutObject()->positionForPoint(dragStartPos)) < 0)
+                newSelection.setExtent(positionBeforeNode(rootUserSelectAllForTarget).upstream(CanCrossEditingBoundary));
+            else if (rootUserSelectAllForTarget && mousePressNode->layoutObject())
+                newSelection.setExtent(positionAfterNode(rootUserSelectAllForTarget).downstream(CanCrossEditingBoundary));
+            else
+                newSelection.setExtent(targetPosition);
+        }
+    } else {
+        newSelection.setExtent(targetPosition);
+    }
+
+    if (m_frame->selection().granularity() != CharacterGranularity)
+        newSelection.expandUsingGranularity(m_frame->selection().granularity());
+
+    m_frame->selection().setNonDirectionalSelectionIfNeeded(newSelection, m_frame->selection().granularity(),
+        FrameSelection::AdjustEndpointsAtBidiBoundary);
+}
+
+
+void SelectionController::selectionForContextMenu(const MouseEventWithHitTestResults& mev, const LayoutPoint& position)
+{
+    if (!m_frame->selection().contains(position)
+        && !mev.scrollbar()
+        // FIXME: In the editable case, word selection sometimes selects content that isn't underneath the mouse.
+        // If the selection is non-editable, we do word selection to make it easier to use the contextual menu items
+        // available for text selections.  But only if we're above text.
+        && (m_frame->selection().isContentEditable() || (mev.innerNode() && mev.innerNode()->isTextNode()))) {
+        m_allowSelection = true; // context menu events are always allowed to perform a selection
+
+        if (mev.hitTestResult().isMisspelled())
+            selectClosestMisspellingFromMouseEvent(mev);
+        else if (m_frame->editor().behavior().shouldSelectOnContextualMenuClick())
+            selectClosestWordOrLinkFromMouseEvent(mev);
+    }
+}
+
+void SelectionController::releaseSelection(MouseEventWithHitTestResults& mev)
+{
+    IntPoint p = m_frame->view()->rootFrameToContents(mev.event().position());
+    if (m_frame->selection().contains(p)) {
+        VisiblePosition visiblePos(
+            mev.innerNode()->layoutObject()->positionForPoint(mev.localPoint()));
+        VisibleSelection newSelection(visiblePos);
+        m_frame->selection().setSelection(newSelection);
+    }
+}
+
+void SelectionController::notifySelectionChanged()
+{
+    if (m_frame->selection().isRange())
+        m_selectionState = ExtendedSelection;
+    else if (m_frame->selection().isCaret())
+        m_selectionState = PlacedCaret;
+    else
+        m_selectionState = HaveNotStartedSelection;
+}
+
+} // namespace blink