michael@0: Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // Constants
michael@0: 
michael@0: const PREFILTER_INVISIBLE = nsIAccessibleTraversalRule.PREFILTER_INVISIBLE;
michael@0: const PREFILTER_ARIA_HIDDEN = nsIAccessibleTraversalRule.PREFILTER_ARIA_HIDDEN;
michael@0: const PREFILTER_TRANSPARENT = nsIAccessibleTraversalRule.PREFILTER_TRANSPARENT;
michael@0: const FILTER_MATCH = nsIAccessibleTraversalRule.FILTER_MATCH;
michael@0: const FILTER_IGNORE = nsIAccessibleTraversalRule.FILTER_IGNORE;
michael@0: const FILTER_IGNORE_SUBTREE = nsIAccessibleTraversalRule.FILTER_IGNORE_SUBTREE;
michael@0: const CHAR_BOUNDARY = nsIAccessiblePivot.CHAR_BOUNDARY;
michael@0: const WORD_BOUNDARY = nsIAccessiblePivot.WORD_BOUNDARY;
michael@0: 
michael@0: const NS_ERROR_NOT_IN_TREE = 0x80780026;
michael@0: const NS_ERROR_INVALID_ARG = 0x80070057;
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // Traversal rules
michael@0: 
michael@0: /**
michael@0:  * Rule object to traverse all focusable nodes and text nodes.
michael@0:  */
michael@0: var HeadersTraversalRule =
michael@0: {
michael@0:   getMatchRoles: function(aRules)
michael@0:   {
michael@0:     aRules.value = [ROLE_HEADING];
michael@0:     return aRules.value.length;
michael@0:   },
michael@0: 
michael@0:   preFilter: PREFILTER_INVISIBLE,
michael@0: 
michael@0:   match: function(aAccessible)
michael@0:   {
michael@0:     return FILTER_MATCH;
michael@0:   },
michael@0: 
michael@0:   QueryInterface: XPCOMUtils.generateQI([nsIAccessibleTraversalRule])
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Traversal rule for all focusable nodes or leafs.
michael@0:  */
michael@0: var ObjectTraversalRule =
michael@0: {
michael@0:   getMatchRoles: function(aRules)
michael@0:   {
michael@0:     aRules.value = [];
michael@0:     return 0;
michael@0:   },
michael@0: 
michael@0:   preFilter: PREFILTER_INVISIBLE | PREFILTER_ARIA_HIDDEN | PREFILTER_TRANSPARENT,
michael@0: 
michael@0:   match: function(aAccessible)
michael@0:   {
michael@0:     var rv = FILTER_IGNORE;
michael@0:     var role = aAccessible.role;
michael@0:     if (hasState(aAccessible, STATE_FOCUSABLE) &&
michael@0:         (role != ROLE_DOCUMENT && role != ROLE_INTERNAL_FRAME))
michael@0:       rv = FILTER_IGNORE_SUBTREE | FILTER_MATCH;
michael@0:     else if (aAccessible.childCount == 0 &&
michael@0:              role != ROLE_STATICTEXT && aAccessible.name.trim())
michael@0:       rv = FILTER_MATCH;
michael@0: 
michael@0:     return rv;
michael@0:   },
michael@0: 
michael@0:   QueryInterface: XPCOMUtils.generateQI([nsIAccessibleTraversalRule])
michael@0: };
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: // Virtual state invokers and checkers
michael@0: 
michael@0: /**
michael@0:  * A checker for virtual cursor changed events.
michael@0:  */
michael@0: function VCChangedChecker(aDocAcc, aIdOrNameOrAcc, aTextOffsets, aPivotMoveMethod)
michael@0: {
michael@0:   this.__proto__ = new invokerChecker(EVENT_VIRTUALCURSOR_CHANGED, aDocAcc);
michael@0: 
michael@0:   this.match = function VCChangedChecker_check(aEvent)
michael@0:   {
michael@0:     var event = null;
michael@0:     try {
michael@0:       event = aEvent.QueryInterface(nsIAccessibleVirtualCursorChangeEvent);
michael@0:     } catch (e) {
michael@0:       return false;
michael@0:     }
michael@0: 
michael@0:     var expectedReason = VCChangedChecker.methodReasonMap[aPivotMoveMethod] ||
michael@0:       nsIAccessiblePivot.REASON_NONE;
michael@0: 
michael@0:     return event.reason == expectedReason;
michael@0:   };
michael@0: 
michael@0:   this.check = function VCChangedChecker_check(aEvent)
michael@0:   {
michael@0:     SimpleTest.info("VCChangedChecker_check");
michael@0: 
michael@0:     var event = null;
michael@0:     try {
michael@0:       event = aEvent.QueryInterface(nsIAccessibleVirtualCursorChangeEvent);
michael@0:     } catch (e) {
michael@0:       SimpleTest.ok(false, "Does not support correct interface: " + e);
michael@0:     }
michael@0: 
michael@0:     var position = aDocAcc.virtualCursor.position;
michael@0:     var idMatches = position && position.DOMNode.id == aIdOrNameOrAcc;
michael@0:     var nameMatches = position && position.name == aIdOrNameOrAcc;
michael@0:     var accMatches = position == aIdOrNameOrAcc;
michael@0: 
michael@0:     SimpleTest.ok(idMatches || nameMatches || accMatches, "id or name matches",
michael@0:                   "expecting " + aIdOrNameOrAcc + ", got '" +
michael@0:                   prettyName(position));
michael@0: 
michael@0:     if (aTextOffsets) {
michael@0:       SimpleTest.is(aDocAcc.virtualCursor.startOffset, aTextOffsets[0],
michael@0:                     "wrong start offset");
michael@0:       SimpleTest.is(aDocAcc.virtualCursor.endOffset, aTextOffsets[1],
michael@0:                     "wrong end offset");
michael@0:     }
michael@0: 
michael@0:     var prevPosAndOffset = VCChangedChecker.
michael@0:       getPreviousPosAndOffset(aDocAcc.virtualCursor);
michael@0: 
michael@0:     if (prevPosAndOffset) {
michael@0:       SimpleTest.is(event.oldAccessible, prevPosAndOffset.position,
michael@0:                     "previous position does not match");
michael@0:       SimpleTest.is(event.oldStartOffset, prevPosAndOffset.startOffset,
michael@0:                     "previous start offset does not match");
michael@0:       SimpleTest.is(event.oldEndOffset, prevPosAndOffset.endOffset,
michael@0:                     "previous end offset does not match");
michael@0:     }
michael@0:   };
michael@0: }
michael@0: 
michael@0: VCChangedChecker.prevPosAndOffset = {};
michael@0: 
michael@0: VCChangedChecker.storePreviousPosAndOffset =
michael@0:   function storePreviousPosAndOffset(aPivot)
michael@0: {
michael@0:   VCChangedChecker.prevPosAndOffset[aPivot] =
michael@0:     {position: aPivot.position,
michael@0:      startOffset: aPivot.startOffset,
michael@0:      endOffset: aPivot.endOffset};
michael@0: };
michael@0: 
michael@0: VCChangedChecker.getPreviousPosAndOffset =
michael@0:   function getPreviousPosAndOffset(aPivot)
michael@0: {
michael@0:   return VCChangedChecker.prevPosAndOffset[aPivot];
michael@0: };
michael@0: 
michael@0: VCChangedChecker.methodReasonMap = {
michael@0:   'moveNext': nsIAccessiblePivot.REASON_NEXT,
michael@0:   'movePrevious': nsIAccessiblePivot.REASON_PREV,
michael@0:   'moveFirst': nsIAccessiblePivot.REASON_FIRST,
michael@0:   'moveLast': nsIAccessiblePivot.REASON_LAST,
michael@0:   'setTextRange': nsIAccessiblePivot.REASON_TEXT,
michael@0:   'moveNextByText': nsIAccessiblePivot.REASON_TEXT,
michael@0:   'movePreviousByText': nsIAccessiblePivot.REASON_TEXT,
michael@0:   'moveToPoint': nsIAccessiblePivot.REASON_POINT
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Set a text range in the pivot and wait for virtual cursor change event.
michael@0:  *
michael@0:  * @param aDocAcc         [in] document that manages the virtual cursor
michael@0:  * @param aTextAccessible [in] accessible to set to virtual cursor's position
michael@0:  * @param aTextOffsets    [in] start and end offsets of text range to set in
michael@0:  *                        virtual cursor.
michael@0:  */
michael@0: function setVCRangeInvoker(aDocAcc, aTextAccessible, aTextOffsets)
michael@0: {
michael@0:   this.invoke = function virtualCursorChangedInvoker_invoke()
michael@0:   {
michael@0:     VCChangedChecker.
michael@0:       storePreviousPosAndOffset(aDocAcc.virtualCursor);
michael@0:     SimpleTest.info(prettyName(aTextAccessible) + " " + aTextOffsets);
michael@0:     aDocAcc.virtualCursor.setTextRange(aTextAccessible,
michael@0:                                        aTextOffsets[0],
michael@0:                                        aTextOffsets[1]);
michael@0:   };
michael@0: 
michael@0:   this.getID = function setVCRangeInvoker_getID()
michael@0:   {
michael@0:     return "Set offset in " + prettyName(aTextAccessible) +
michael@0:       " to (" + aTextOffsets[0] + ", " + aTextOffsets[1] + ")";
michael@0:   };
michael@0: 
michael@0:   this.eventSeq = [
michael@0:     new VCChangedChecker(aDocAcc, aTextAccessible, aTextOffsets, "setTextRange")
michael@0:   ];
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Move the pivot and wait for virtual cursor change event.
michael@0:  *
michael@0:  * @param aDocAcc          [in] document that manages the virtual cursor
michael@0:  * @param aPivotMoveMethod [in] method to test (ie. "moveNext", "moveFirst", etc.)
michael@0:  * @param aRule            [in] traversal rule object
michael@0:  * @param aIdOrNameOrAcc   [in] id, accessible or accessible name to expect
michael@0:  *                         virtual cursor to land on after performing move method.
michael@0:  *                         false if no move is expected.
michael@0:  */
michael@0: function setVCPosInvoker(aDocAcc, aPivotMoveMethod, aRule, aIdOrNameOrAcc)
michael@0: {
michael@0:   var expectMove = (aIdOrNameOrAcc != false);
michael@0:   this.invoke = function virtualCursorChangedInvoker_invoke()
michael@0:   {
michael@0:     VCChangedChecker.
michael@0:       storePreviousPosAndOffset(aDocAcc.virtualCursor);
michael@0:     if (aPivotMoveMethod && aRule) {
michael@0:       var moved = aDocAcc.virtualCursor[aPivotMoveMethod](aRule);
michael@0:       SimpleTest.is(!!moved, !!expectMove,
michael@0:                     "moved pivot with " + aPivotMoveMethod +
michael@0:                     " to " + aIdOrNameOrAcc);
michael@0:     } else {
michael@0:       aDocAcc.virtualCursor.position = getAccessible(aIdOrNameOrAcc);
michael@0:     }
michael@0:   };
michael@0: 
michael@0:   this.getID = function setVCPosInvoker_getID()
michael@0:   {
michael@0:     return "Do " + (expectMove ? "" : "no-op ") + aPivotMoveMethod;
michael@0:   };
michael@0: 
michael@0:   if (expectMove) {
michael@0:     this.eventSeq = [
michael@0:       new VCChangedChecker(aDocAcc, aIdOrNameOrAcc, null, aPivotMoveMethod)
michael@0:     ];
michael@0:   } else {
michael@0:     this.eventSeq = [];
michael@0:     this.unexpectedEventSeq = [
michael@0:       new invokerChecker(EVENT_VIRTUALCURSOR_CHANGED, aDocAcc)
michael@0:     ];
michael@0:   }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Move the pivot by text and wait for virtual cursor change event.
michael@0:  *
michael@0:  * @param aDocAcc          [in] document that manages the virtual cursor
michael@0:  * @param aPivotMoveMethod [in] method to test (ie. "moveNext", "moveFirst", etc.)
michael@0:  * @param aBoundary        [in] boundary constant
michael@0:  * @param aTextOffsets     [in] start and end offsets of text range to set in
michael@0:  *                         virtual cursor.
michael@0:  * @param aIdOrNameOrAcc   [in] id, accessible or accessible name to expect
michael@0:  *                         virtual cursor to land on after performing move method.
michael@0:  *                         false if no move is expected.
michael@0:  */
michael@0: function setVCTextInvoker(aDocAcc, aPivotMoveMethod, aBoundary, aTextOffsets, aIdOrNameOrAcc)
michael@0: {
michael@0:   var expectMove = (aIdOrNameOrAcc != false);
michael@0:   this.invoke = function virtualCursorChangedInvoker_invoke()
michael@0:   {
michael@0:     VCChangedChecker.storePreviousPosAndOffset(aDocAcc.virtualCursor);
michael@0:     SimpleTest.info(aDocAcc.virtualCursor.position);
michael@0:     var moved = aDocAcc.virtualCursor[aPivotMoveMethod](aBoundary);
michael@0:     SimpleTest.is(!!moved, !!expectMove,
michael@0:                   "moved pivot by text with " + aPivotMoveMethod +
michael@0:                   " to " + aIdOrNameOrAcc);
michael@0:   };
michael@0: 
michael@0:   this.getID = function setVCPosInvoker_getID()
michael@0:   {
michael@0:     return "Do " + (expectMove ? "" : "no-op ") + aPivotMoveMethod + " in " +
michael@0:       prettyName(aIdOrNameOrAcc) + ", " + boundaryToString(aBoundary) +
michael@0:       ", [" + aTextOffsets + "]";
michael@0:   };
michael@0: 
michael@0:   if (expectMove) {
michael@0:     this.eventSeq = [
michael@0:       new VCChangedChecker(aDocAcc, aIdOrNameOrAcc, aTextOffsets, aPivotMoveMethod)
michael@0:     ];
michael@0:   } else {
michael@0:     this.eventSeq = [];
michael@0:     this.unexpectedEventSeq = [
michael@0:       new invokerChecker(EVENT_VIRTUALCURSOR_CHANGED, aDocAcc)
michael@0:     ];
michael@0:   }
michael@0: }
michael@0: 
michael@0: 
michael@0: /**
michael@0:  * Move the pivot to the position under the point.
michael@0:  *
michael@0:  * @param aDocAcc        [in] document that manages the virtual cursor
michael@0:  * @param aX             [in] screen x coordinate
michael@0:  * @param aY             [in] screen y coordinate
michael@0:  * @param aIgnoreNoMatch [in] don't unset position if no object was found at
michael@0:  *                       point.
michael@0:  * @param aRule          [in] traversal rule object
michael@0:  * @param aIdOrNameOrAcc [in] id, accessible or accessible name to expect
michael@0:  *                       virtual cursor to land on after performing move method.
michael@0:  *                       false if no move is expected.
michael@0:  */
michael@0: function moveVCCoordInvoker(aDocAcc, aX, aY, aIgnoreNoMatch,
michael@0:                             aRule, aIdOrNameOrAcc)
michael@0: {
michael@0:   var expectMove = (aIdOrNameOrAcc != false);
michael@0:   this.invoke = function virtualCursorChangedInvoker_invoke()
michael@0:   {
michael@0:     VCChangedChecker.
michael@0:       storePreviousPosAndOffset(aDocAcc.virtualCursor);
michael@0:     var moved = aDocAcc.virtualCursor.moveToPoint(aRule, aX, aY,
michael@0:                                                   aIgnoreNoMatch);
michael@0:     SimpleTest.ok((expectMove && moved) || (!expectMove && !moved),
michael@0:                   "moved pivot");
michael@0:   };
michael@0: 
michael@0:   this.getID = function setVCPosInvoker_getID()
michael@0:   {
michael@0:     return "Do " + (expectMove ? "" : "no-op ") + "moveToPoint " + aIdOrNameOrAcc;
michael@0:   };
michael@0: 
michael@0:   if (expectMove) {
michael@0:     this.eventSeq = [
michael@0:       new VCChangedChecker(aDocAcc, aIdOrNameOrAcc, null, 'moveToPoint')
michael@0:     ];
michael@0:   } else {
michael@0:     this.eventSeq = [];
michael@0:     this.unexpectedEventSeq = [
michael@0:       new invokerChecker(EVENT_VIRTUALCURSOR_CHANGED, aDocAcc)
michael@0:     ];
michael@0:   }
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Change the pivot modalRoot
michael@0:  *
michael@0:  * @param aDocAcc         [in] document that manages the virtual cursor
michael@0:  * @param aModalRootAcc   [in] accessible of the modal root, or null
michael@0:  * @param aExpectedResult [in] error result expected. 0 if expecting success
michael@0:  */
michael@0: function setModalRootInvoker(aDocAcc, aModalRootAcc, aExpectedResult)
michael@0: {
michael@0:   this.invoke = function setModalRootInvoker_invoke()
michael@0:   {
michael@0:     var errorResult = 0;
michael@0:     try {
michael@0:       aDocAcc.virtualCursor.modalRoot = aModalRootAcc;
michael@0:     } catch (x) {
michael@0:       SimpleTest.ok(
michael@0:         x.result, "Unexpected exception when changing modal root: " + x);
michael@0:       errorResult = x.result;
michael@0:     }
michael@0: 
michael@0:     SimpleTest.is(errorResult, aExpectedResult,
michael@0:                   "Did not get expected result when changing modalRoot");
michael@0:   };
michael@0: 
michael@0:   this.getID = function setModalRootInvoker_getID()
michael@0:   {
michael@0:     return "Set modalRoot to " + prettyName(aModalRootAcc);
michael@0:   };
michael@0: 
michael@0:   this.eventSeq = [];
michael@0:   this.unexpectedEventSeq = [
michael@0:     new invokerChecker(EVENT_VIRTUALCURSOR_CHANGED, aDocAcc)
michael@0:   ];
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Add invokers to a queue to test a rule and an expected sequence of element ids
michael@0:  * or accessible names for that rule in the given document.
michael@0:  *
michael@0:  * @param aQueue     [in] event queue in which to push invoker sequence.
michael@0:  * @param aDocAcc    [in] the managing document of the virtual cursor we are
michael@0:  *                   testing
michael@0:  * @param aRule      [in] the traversal rule to use in the invokers
michael@0:  * @param aModalRoot [in] a modal root to use in this traversal sequence
michael@0:  * @param aSequence  [in] a sequence of accessible names or element ids to expect
michael@0:  *                   with the given rule in the given document
michael@0:  */
michael@0: function queueTraversalSequence(aQueue, aDocAcc, aRule, aModalRoot, aSequence)
michael@0: {
michael@0:   aDocAcc.virtualCursor.position = null;
michael@0: 
michael@0:   // Add modal root (if any)
michael@0:   aQueue.push(new setModalRootInvoker(aDocAcc, aModalRoot, 0));
michael@0: 
michael@0:   aQueue.push(new setVCPosInvoker(aDocAcc, "moveFirst", aRule, aSequence[0]));
michael@0: 
michael@0:   for (var i = 1; i < aSequence.length; i++) {
michael@0:     var invoker =
michael@0:       new setVCPosInvoker(aDocAcc, "moveNext", aRule, aSequence[i]);
michael@0:     aQueue.push(invoker);
michael@0:   }
michael@0: 
michael@0:   // No further more matches for given rule, expect no virtual cursor changes.
michael@0:   aQueue.push(new setVCPosInvoker(aDocAcc, "moveNext", aRule, false));
michael@0: 
michael@0:   for (var i = aSequence.length-2; i >= 0; i--) {
michael@0:     var invoker =
michael@0:       new setVCPosInvoker(aDocAcc, "movePrevious", aRule, aSequence[i]);
michael@0:     aQueue.push(invoker);
michael@0:   }
michael@0: 
michael@0:   // No previous more matches for given rule, expect no virtual cursor changes.
michael@0:   aQueue.push(new setVCPosInvoker(aDocAcc, "movePrevious", aRule, false));
michael@0: 
michael@0:   aQueue.push(new setVCPosInvoker(aDocAcc, "moveLast", aRule,
michael@0:                                   aSequence[aSequence.length - 1]));
michael@0: 
michael@0:   // No further more matches for given rule, expect no virtual cursor changes.
michael@0:   aQueue.push(new setVCPosInvoker(aDocAcc, "moveNext", aRule, false));
michael@0: 
michael@0:   aQueue.push(new setVCPosInvoker(aDocAcc, "moveFirst", aRule, aSequence[0]));
michael@0: 
michael@0:   // No previous more matches for given rule, expect no virtual cursor changes.
michael@0:   aQueue.push(new setVCPosInvoker(aDocAcc, "movePrevious", aRule, false));
michael@0: 
michael@0:   // Remove modal root (if any).
michael@0:   aQueue.push(new setModalRootInvoker(aDocAcc, null, 0));
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * A checker for removing an accessible while the virtual cursor is on it.
michael@0:  */
michael@0: function removeVCPositionChecker(aDocAcc, aHiddenParentAcc)
michael@0: {
michael@0:   this.__proto__ = new invokerChecker(EVENT_REORDER, aHiddenParentAcc);
michael@0: 
michael@0:   this.check = function removeVCPositionChecker_check(aEvent) {
michael@0:     var errorResult = 0;
michael@0:     try {
michael@0:       aDocAcc.virtualCursor.moveNext(ObjectTraversalRule);
michael@0:     } catch (x) {
michael@0:       errorResult = x.result;
michael@0:     }
michael@0:     SimpleTest.is(
michael@0:       errorResult, NS_ERROR_NOT_IN_TREE,
michael@0:       "Expecting NOT_IN_TREE error when moving pivot from invalid position.");
michael@0:   };
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Put the virtual cursor's position on an object, and then remove it.
michael@0:  *
michael@0:  * @param aDocAcc     [in] document that manages the virtual cursor
michael@0:  * @param aPosNode    [in] DOM node to hide after virtual cursor's position is
michael@0:  *                    set to it.
michael@0:  */
michael@0: function removeVCPositionInvoker(aDocAcc, aPosNode)
michael@0: {
michael@0:   this.accessible = getAccessible(aPosNode);
michael@0:   this.invoke = function removeVCPositionInvoker_invoke()
michael@0:   {
michael@0:     aDocAcc.virtualCursor.position = this.accessible;
michael@0:     aPosNode.parentNode.removeChild(aPosNode);
michael@0:   };
michael@0: 
michael@0:   this.getID = function removeVCPositionInvoker_getID()
michael@0:   {
michael@0:     return "Bring virtual cursor to accessible, and remove its DOM node.";
michael@0:   };
michael@0: 
michael@0:   this.eventSeq = [
michael@0:     new removeVCPositionChecker(aDocAcc, this.accessible.parent)
michael@0:   ];
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * A checker for removing the pivot root and then calling moveFirst, and
michael@0:  * checking that an exception is thrown.
michael@0:  */
michael@0: function removeVCRootChecker(aPivot)
michael@0: {
michael@0:   this.__proto__ = new invokerChecker(EVENT_REORDER, aPivot.root.parent);
michael@0: 
michael@0:   this.check = function removeVCRootChecker_check(aEvent) {
michael@0:     var errorResult = 0;
michael@0:     try {
michael@0:       aPivot.moveLast(ObjectTraversalRule);
michael@0:     } catch (x) {
michael@0:       errorResult = x.result;
michael@0:     }
michael@0:     SimpleTest.is(
michael@0:       errorResult, NS_ERROR_NOT_IN_TREE,
michael@0:       "Expecting NOT_IN_TREE error when moving pivot from invalid position.");
michael@0:   };
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * Create a pivot, remove its root, and perform an operation where the root is
michael@0:  * needed.
michael@0:  *
michael@0:  * @param aRootNode [in] DOM node of which accessible will be the root of the
michael@0:  *                       pivot. Should have more than one child.
michael@0:  */
michael@0: function removeVCRootInvoker(aRootNode)
michael@0: {
michael@0:   this.pivot = gAccRetrieval.createAccessiblePivot(getAccessible(aRootNode));
michael@0:   this.invoke = function removeVCRootInvoker_invoke()
michael@0:   {
michael@0:     this.pivot.position = this.pivot.root.firstChild;
michael@0:     aRootNode.parentNode.removeChild(aRootNode);
michael@0:   };
michael@0: 
michael@0:   this.getID = function removeVCRootInvoker_getID()
michael@0:   {
michael@0:     return "Remove root of pivot from tree.";
michael@0:   };
michael@0: 
michael@0:   this.eventSeq = [
michael@0:     new removeVCRootChecker(this.pivot)
michael@0:   ];
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * A debug utility for writing proper sequences for queueTraversalSequence.
michael@0:  */
michael@0: function dumpTraversalSequence(aPivot, aRule)
michael@0: {
michael@0:   var sequence = [];
michael@0:   if (aPivot.moveFirst(aRule)) {
michael@0:     do {
michael@0:       sequence.push("'" + prettyName(aPivot.position) + "'");
michael@0:     } while (aPivot.moveNext(aRule))
michael@0:   }
michael@0:   SimpleTest.info("\n[" + sequence.join(", ") + "]\n");
michael@0: }