RetroZilla/extensions/xforms/nsXFormsInsertDeleteElement.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is XForms code.
 *
 * The Initial Developer of the Original Code is
 * Novell, Inc.
 * Portions created by the Initial Developer are Copyright (C) 2005
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Allan Beaufour <abeaufour@novell.com>
 *  Merle Sterling <msterlin@us.ibm.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsIDOMAttr.h"
#include "nsIDOMEvent.h"
#include "nsIDOMNode.h"
#include "nsIDOMElement.h"
#include "nsIDOMDocument.h"
#include "nsIDOMNodeList.h"
#include "nsIDOMNamedNodeMap.h"
#include "nsIXFormsRepeatElement.h"
#include "nsIXFormsControl.h"
#include "nsIXFormsContextInfo.h"

#include "nsString.h"

#include "nsIInstanceElementPrivate.h"
#include "nsXFormsActionModuleBase.h"
#include "nsXFormsActionElement.h"
#include "nsXFormsUtils.h"
#include "nsIDOM3Node.h"

#include "math.h"

#ifdef DEBUG
//#define DEBUG_XF_INSERTDELETE
#endif

/**
 * Implementation of the XForms \<insert\> and \<delete\> elements.
 */
class nsXFormsInsertDeleteElement : public nsXFormsActionModuleBase
{
private:
  PRBool mIsInsert;

  enum Location {
    eLocation_After,
    eLocation_Before,
    eLocation_FirstChild
  };

  // Context Info for events.
  nsCOMArray<nsIXFormsContextInfo> mContextInfo;

  /** Get the first node of a given type in aNodes.
   *
   *  @param aNodes        array of nodes
   *  @param aNodeType     type of node to find
   *
   *  @return aResult      node of type aNodeType
   */
  nsresult GetFirstNodeOfType(nsCOMArray<nsIDOMNode> *aNodes,
                              PRUint16 aNodeType,
                              nsIDOMNode **aResult);

  /** Insert a node.
   *
   *  @param aTargetNode     target location node
   *  @param aNewNode        node to insert
   *  @param aLocation       insert location relative to target
   *
   *  @return aResult        result node
   */
  nsresult InsertNode(nsIDOMNode *aTargetNode, nsIDOMNode *aNewNode,
                      Location aLocation, nsIDOMNode **aResNode);

  nsresult RefreshRepeats(nsCOMArray<nsIDOMNode> *aNodes);

public:

  /** Constructor */
  nsXFormsInsertDeleteElement(PRBool aIsInsert) :
    mIsInsert(aIsInsert)
    {}

  NS_IMETHOD
  HandleAction(nsIDOMEvent* aEvent, nsIXFormsActionElement *aParentAction);

  /**
   * Normally, an action element implements the body of its action handler
   * using this method; however, since an `nsXFormsInsertDeleteElement` sets
   * up additional context before evaluating `if` and `while`, it overrides
   * the `HandleAction` method instead to get full control over the
   * execution of its action.
   */
  nsresult HandleSingleAction(nsIDOMEvent* aEvent,
                              nsIXFormsActionElement *aParentAction)
  {
    return NS_OK;
  }
};

NS_IMETHODIMP
nsXFormsInsertDeleteElement::HandleAction(nsIDOMEvent            *aEvent,
                                          nsIXFormsActionElement *aParentAction)
{
  // Keep element alive while iterating.
  nsCOMPtr<nsIDOMElement> element = mElement;
  if (!element)
    return NS_OK;

  mCurrentEvent = aEvent;

  nsresult rv;

  // Set the maximum run time for the loop (in microseconds).
  PRTime microseconds = nsXFormsUtils::waitLimit * PR_USEC_PER_SEC;
  PRTime runTime = 0, start = PR_Now();
  while (PR_TRUE) {
    //
    // Step 1 (Insert or Delete): Determine the insert/delete context.
    //
    // If the bind attribute is present or if the context attribute is not given,
    // the insert context is the in-scope evaluation context. Otherwise, the
    // XPath expression provided by the context attribute is evaluated using the
    // in-scope evaluation context, and the first node rule is applied to obtain
    // the insert context.
    //
    nsCOMPtr<nsIDOMXPathResult> contextNodeset;
    nsCOMPtr<nsIDOMNode> contextNode;
    PRUint32 contextNodesetSize = 0;
    PRInt32 contextPosition;

    // Get the in-scope evaluation context. The last parameter to GetNodeContext
    // indicates whether it should try to get the context using @bind. We want to
    // ignore @bind because it should not change the in-scope evaluation context
    // for insert.
    nsCOMPtr<nsIModelElementPrivate> model;
    nsCOMPtr<nsIDOMElement> bindElement;
    nsCOMPtr<nsIXFormsControl> parentControl;
    PRBool outerBind;
    rv = nsXFormsUtils::GetNodeContext(element,
                                       nsXFormsUtils::ELEMENT_WITH_MODEL_ATTR,
                                       getter_AddRefs(model),
                                       getter_AddRefs(bindElement),
                                       &outerBind,
                                       getter_AddRefs(parentControl),
                                       getter_AddRefs(contextNode),
                                       &contextPosition,
                                       (PRInt32*)&contextNodesetSize,
                                       PR_FALSE);

    NS_ENSURE_SUCCESS(rv, rv);

    // Determine if the context node is specified via @context.
    // If @bind is present, @context is ignored.
    nsAutoString bindExpr;
    nsAutoString contextExpr;
    element->GetAttribute(NS_LITERAL_STRING("bind"), bindExpr);
    element->GetAttribute(NS_LITERAL_STRING("context"), contextExpr);

    if (bindExpr.IsEmpty() && !contextExpr.IsEmpty()) {
      // @context is specified and overrides the in-scope evaluation context.
      // The insert context is the result of evaluating @context in the current
      // in-scope evaluation context.
      rv = nsXFormsUtils::EvaluateXPath(contextExpr, contextNode, element,
                                        nsIDOMXPathResult::ORDERED_NODE_SNAPSHOT_TYPE,
                                        getter_AddRefs(contextNodeset));
      NS_ENSURE_SUCCESS(rv, rv);

      // The insert/delete action is terminated with no effect if the context
      // is the empty node-set.
      if (contextNodeset) {
        rv = contextNodeset->GetSnapshotLength(&contextNodesetSize);
        NS_ENSURE_SUCCESS(rv, rv);
    
        if (contextNodesetSize < 1)
          return NS_OK;
    
        // Context node is the first node in the nodeset.
        contextNodeset->SnapshotItem(0, getter_AddRefs(contextNode));
        contextPosition = 1;
      }
    }

    // The insert/delete action is terminated with no effect if the context
    // is the empty node-set.
    if (!contextNode)
      return NS_OK;

    // The insert action is terminated with no effect if the context attribute
    // is given and the insert context does not evaluate to an element node.
    if (mIsInsert && !contextExpr.IsEmpty()) {
      PRUint16 nodeType;
      contextNode->GetNodeType(&nodeType);
      if (nodeType != nsIDOMNode::ELEMENT_NODE)
        return NS_OK;
    }

    // Test the `if` and `while` attributes to determine whether this action
    // can be performed and should be repeated.  As the insert and delete
    // actions can change their context, we do this testing here instead of
    // relying on the default logic from our parent class' `HandleAction`
    // (or `DoHandleAction`) definition.
    PRBool usesWhile;
    if (!nsXFormsActionModuleBase::CanPerformAction(element, &usesWhile,
                                                    contextNode,
                                                    contextNodesetSize,
                                                    contextPosition)) {
      return NS_OK;
    }
  
    //
    // Step 2 (Insert or Delete): Determine the node-set binding.
    //
    // If the bind attribute is present, it directly determines the Node Set
    // Binding node-set. If a nodeset attribute is present, it is evaluated
    // within the context to determine the Node Set Binding node-set.
    //
    // A NodeSet binding attribute (@bind or @nodeset) is required unless
    // the context attribute is present.
    //
    nsCOMPtr<nsIDOMXPathResult> nodeset;
    PRUint32 nodesetSize = 0;
    nsAutoString nodesetExpr;

    if (bindExpr.IsEmpty()) {
      element->GetAttribute(NS_LITERAL_STRING("nodeset"), nodesetExpr);
      if (!nodesetExpr.IsEmpty()) {
        // Evaluate the nodeset attribute within the insert context.
        rv = nsXFormsUtils::EvaluateXPath(nodesetExpr, contextNode, element,
                                          nsIDOMXPathResult::ORDERED_NODE_SNAPSHOT_TYPE,
                                          getter_AddRefs(nodeset));
        NS_ENSURE_SUCCESS(rv, rv);
      }
    } else {
      PRBool usesModelBinding;
      rv = nsXFormsUtils::EvaluateNodeBinding(element,
                                              nsXFormsUtils::ELEMENT_WITH_MODEL_ATTR,
                                              EmptyString(),
                                              EmptyString(),
                                              nsIDOMXPathResult::ORDERED_NODE_SNAPSHOT_TYPE,
                                              getter_AddRefs(model),
                                              getter_AddRefs(nodeset),
                                              &usesModelBinding);
      NS_ENSURE_SUCCESS(rv, rv);

      if (!model)
        return NS_OK;
    }

    if (nodeset) {
      rv = nodeset->GetSnapshotLength(&nodesetSize);
      NS_ENSURE_SUCCESS(rv, rv);
    }

    // The insert action is terminated with no effect if the context attribute
    // is not given and the Node Set Binding node-set is the empty node-set.
    //
    // The delete action is terminated with no effect if the Node Set Binding
    // node-set is the empty node-set.
    if (!nodeset || nodesetSize < 1) {
      if (!mIsInsert || (mIsInsert && contextExpr.IsEmpty()))
        return NS_OK;
    }

    //
    // Step 3 (Insert): Determine the origin node-set.
    //
    nsCOMPtr<nsIDOMXPathResult> originNodeset;
    nsCOMPtr<nsIDOMXPathResult> originNode;
    PRUint32 originNodesetSize = 0;

    if (mIsInsert) {
      // If the origin attribute is not given and the Node Set Binding node-set
      // is empty, then the origin node-set is the empty node-set. Otherwise,
      // if the origin attribute is not given, then the origin node-set consists
      // of the last node of the Node Set Binding node-set (which we will obtain
      // just before performing the insert).
      //
      // If the origin attribute is given, the origin node-set is the result of
      // the evaluation of the origin attribute in the insert context.
      nsAutoString origin;
      element->GetAttribute(NS_LITERAL_STRING("origin"), origin);

      if (!origin.IsEmpty()) {
        rv = nsXFormsUtils::EvaluateXPath(origin, contextNode, element,
                                          nsIDOMXPathResult::ORDERED_NODE_SNAPSHOT_TYPE,
                                          getter_AddRefs(originNodeset));
        NS_ENSURE_SUCCESS(rv, rv);

        // The insert action is terminated with no effect if the origin node-set
        // is the empty node-set.
        if (!originNodeset)
          return NS_OK;

        rv = originNodeset->GetSnapshotLength(&originNodesetSize);
        NS_ENSURE_SUCCESS(rv, rv);

        // The insert action is terminated with no effect if the origin node-set
        // is the empty node-set.
        if (originNodesetSize < 1)
          return NS_OK;

        // Context Info: 'origin-nodes'
        nsCOMPtr<nsXFormsContextInfo> contextInfo =
          new nsXFormsContextInfo(element);
        NS_ENSURE_TRUE(contextInfo, NS_ERROR_OUT_OF_MEMORY);
        contextInfo->SetNodesetValue("origin-nodes", originNodeset);
        mContextInfo.AppendObject(contextInfo);
      }
    }

    //
    // Step 4 (Insert), Step 3 (Delete):
    // Determine the insert/delete location node.
    //
    // Insert: If the Node Set Binding node-set is not specified or empty, the
    // insert location node is the insert context node. Otherwise, if the at
    // attribute is not given, then the insert location node is the last node
    // of the Node Set Binding node-set. Otherwise, an insert location node is
    // determined from the at attribute.
    //
    // Delete: If the at attribute is not specified, there is no delete location.
    // Otherwise, the delete location is determined by evaluating the XPath
    // expression specified by the at attribute.
    //

    nsCOMPtr<nsIDOMNode> locationNode;
    PRUint32 atInt = 0;
    double atDoub = 0;

    nsAutoString atExpr;
    element->GetAttribute(NS_LITERAL_STRING("at"), atExpr);
          
    if (mIsInsert) {
      if (!nodeset || nodesetSize < 1) {
         // The insert location node is the insert context node.
         locationNode = contextNode;
      } else if (atExpr.IsEmpty()) {
        // The insert location node is the last node of the Node Set Binding
        // node-set.
        nodeset->SnapshotItem(nodesetSize - 1, getter_AddRefs(locationNode));
        NS_ENSURE_STATE(locationNode);
      }
    }

    if (!locationNode) {
      // For insert, we have a nodeset and got past the special cases of an empty
      // nodeset or no @at expression so the insert location node is determined by
      // @at.
      //
      // For delete, the delete location is determined by the @at expression if
      // present; otherwise there is no delete location and each node in the
      // Node Set Binding node-set is deleted, unless the node is the root
      // document element of an instance.
      if (!atExpr.IsEmpty()) {
        // The evaluation context node is the first node in document order of
        // the Node Set Binding node-set.
        nsCOMPtr<nsIDOMNode> evalContextNode;
        nodeset->SnapshotItem(0, getter_AddRefs(evalContextNode));

        // The context size is the size of the Node Set Binding node-set and
        // the context position is 1.
        nsCOMPtr<nsIDOMXPathResult> xpRes;
        rv = nsXFormsUtils::EvaluateXPath(atExpr, evalContextNode, element,
                                          nsIDOMXPathResult::NUMBER_TYPE,
                                          getter_AddRefs(xpRes), 1, nodesetSize);

        if (xpRes) {
          rv = xpRes->GetNumberValue(&atDoub);
          NS_ENSURE_SUCCESS(rv, rv);
        }

        // Determine the insert/delete location.
        if (atDoub < 1) {
          atInt = 1;
        } else {
          // If the location is greater than the nodeset size or NaN,
          // the location is the end of the nodeset.
          // XXX: Need to check for NaN but isnan() is not portable.
          atInt = (PRInt32) floor(atDoub+0.5);
          if (atInt > nodesetSize)
            atInt = nodesetSize;
        }

        // The location node is the node in the Node Set Binding node-set at
        // the position given by the location.
        nodeset->SnapshotItem(atInt - 1, getter_AddRefs(locationNode));
        NS_ENSURE_STATE(locationNode);
      }
    }

    // Context Info: 'insert-location-node' or 'delete-location'
    nsCOMPtr<nsXFormsContextInfo> contextInfo;
    if (mIsInsert) {
      contextInfo = new nsXFormsContextInfo(element);
      NS_ENSURE_TRUE(contextInfo, NS_ERROR_OUT_OF_MEMORY);
      contextInfo->SetNodeValue("insert-location-node", locationNode);
      mContextInfo.AppendObject(contextInfo);
    } else {
      contextInfo = new nsXFormsContextInfo(element);
      NS_ENSURE_TRUE(contextInfo, NS_ERROR_OUT_OF_MEMORY);
      contextInfo->SetNumberValue("delete-location", atInt);
      mContextInfo.AppendObject(contextInfo);
    }

    //
    // Step 5 (Insert): Each node in the origin node-set is cloned in the
    // order it appears in the origin node-set. If the origin node-set is empty
    // (Step 3), the origin node-set consists of the last node of the Node Set
    // Binding node-set.
    //
    // The clones are deep copies of the original nodes except the contents of
    // nodes of type xsd:ID are modified to remain as unique values in the
    // instance data after the clones are inserted.
    //
    // XXX: Need to modify the contents of nodes of type xsd:ID to remain
    // unique.

    nsCOMArray<nsIDOMNode> cloneNodes;
    nsCOMPtr<nsIDOMXPathResult> cloneNodeset;
    PRUint32 cloneNodesetSize = 0;

    if (mIsInsert) {
      nsCOMPtr<nsIDOMNode> prototypeNode, newNode;
      PRUint32 cloneIndex;
      
      // Get prototype node(s) and clone.
      if (originNodesetSize < 1) {
        // Origin nodeset is empty. Clone the last node of nodeset.
        cloneNodeset = nodeset;
        cloneNodesetSize = nodesetSize;
        cloneIndex = nodesetSize - 1;
      } else {
        // Clone all the nodes in the origin node-set.
        cloneNodeset = originNodeset;
        cloneNodesetSize = originNodesetSize;
        cloneIndex = 0;
      }
      // Context Info: 'inserted-nodes'
      nsCOMPtr<nsXFormsContextInfo> contextInfo =
        new nsXFormsContextInfo(element);
      NS_ENSURE_TRUE(contextInfo, NS_ERROR_OUT_OF_MEMORY);
      contextInfo->SetNodesetValue("inserted-nodes", cloneNodeset);
      mContextInfo.AppendObject(contextInfo);

      cloneNodeset->SnapshotItem(cloneIndex, getter_AddRefs(prototypeNode));
      NS_ENSURE_STATE(prototypeNode);

      // The prototypeNode (node to be cloned) and the locationNode (node to
      // which the clone will be inserted) may belong to different instances.
      nsCOMPtr<nsIDOMDocument> originDoc, locationDoc;
      prototypeNode->GetOwnerDocument(getter_AddRefs(originDoc));
      NS_ENSURE_STATE(originDoc);
      locationNode->GetOwnerDocument(getter_AddRefs(locationDoc));
      NS_ENSURE_STATE(locationDoc);

      while ((cloneIndex < cloneNodesetSize) && prototypeNode) {
        if (!SameCOMIdentity(originDoc, locationDoc)) {
          locationDoc->ImportNode(prototypeNode, PR_TRUE, getter_AddRefs(newNode));
        } else {
          prototypeNode->CloneNode(PR_TRUE, getter_AddRefs(newNode));
        }
        NS_ENSURE_STATE(newNode);
        cloneNodes.AppendObject(newNode);

        // Get the next node in the node-set.
        ++cloneIndex;
        cloneNodeset->SnapshotItem(cloneIndex, getter_AddRefs(prototypeNode));
      }
    }

    //
    // Step 6 and 7 (Insert): Determine the target location (Steps 6a-d) and
    // insert all of the nodes that were cloned in Step 5.
    //
    // Step 4 (Delete): Delete the nodes.
    //
    
    nsCOMPtr<nsIDOMDocument> locationDoc;
    nsCOMPtr<nsIDOMElement> locationDocElement;
    nsCOMPtr<nsIDOMNode> parentNode, newNode, resNode, instNode;
    if (mIsInsert) {
      // The cloned node or nodes are inserted in the order they were cloned at
      // their target location depending on their node type.
      nsCOMPtr<nsIDOMNode> newNode;
      
      for (PRInt32 i = 0; i < cloneNodes.Count(); ++i) {
        // Node to be inserted.
        newNode = cloneNodes[i];

        // Get the node type of the insert node and location node.
        PRUint16 newNodeType, locationNodeType;
        newNode->GetNodeType(&newNodeType);
        locationNode->GetNodeType(&locationNodeType);

        // Step 6a - If the Node Set Binding node-set is not specified or empty
        // OR Step 6b - If the Node Set Binding node-set is specified and not
        // empty and the type of the cloned node is different from the type of
        // the insert location node, the target location depends on the node
        // type of the cloned node.
        //
        // If the cloned node is an attribute, then the target location is before
        // the first attribute of the insert location node. If the cloned node is
        // not an attribute, then the target location is before the first child
        // of the insert location node.
        if ((!nodeset || nodesetSize < 1) ||
            (nodeset && nodesetSize > 0 && newNodeType != locationNodeType)) {
          Location location = eLocation_Before;
          nsCOMPtr<nsIDOMNode> targetNode;
          if (newNodeType != nsIDOMNode::ATTRIBUTE_NODE) {
            // Target location is before the first child of location node. If the
            // location node is empty (has no children), it remains the location
            // node and the new node will become the first child of the location
            // node.
            locationNode->GetFirstChild(getter_AddRefs(targetNode));
            if (!targetNode) {
              // New node will become first child of locationNode.
              location = eLocation_FirstChild;
              targetNode = locationNode;
            }
          }
          InsertNode(targetNode, newNode, location, getter_AddRefs(resNode));
        } else {
            // Step 6c - If insert location node is the root element of an
            // instance, then that instance root element location is the target
            // location and the cloned node replaces the instance element. If
            // there is more than one cloned node to insert, only the first node
            // that does not cause a conflict is considered.
            //
            locationNode->GetOwnerDocument(getter_AddRefs(locationDoc));
            NS_ENSURE_STATE(locationDoc);
            locationDoc->GetDocumentElement(getter_AddRefs(locationDocElement));

            if (SameCOMIdentity(locationNode, locationDocElement)) {
              // Step 7 - Replace the instance element with the first element
              // node of the cloned node(s).
              nsCOMPtr<nsIDOMNode> insertNode;
              GetFirstNodeOfType(&cloneNodes, nsIDOMNode::ELEMENT_NODE,
                                 getter_AddRefs(insertNode));
              if (insertNode) {
                nsCOMPtr<nsIDOMNode> child;
                locationDoc->RemoveChild(locationNode, getter_AddRefs(child));
                locationDoc->AppendChild(insertNode, getter_AddRefs(resNode));
                // Done...because we only consider the first node that does
                // not cause a conflict.
                break;
              }
            } else {
              // Step 6d - the target location is immediately before or after the
              // insert location node, based on the position attribute setting or
              // its default.
              PRBool insertAfter = PR_TRUE;
              nsAutoString position;
              element->GetAttribute(NS_LITERAL_STRING("position"), position);
              if (!position.IsEmpty()) {
                if (position.EqualsLiteral("before")) {
                  insertAfter = PR_FALSE;
                } else if (!position.EqualsLiteral("after")) {
                  // This is not a valid document...
                  return NS_ERROR_FAILURE;
                }
              }
              // Context Info: 'position'.
              nsCOMPtr<nsXFormsContextInfo> contextInfo =
                new nsXFormsContextInfo(element);
              NS_ENSURE_TRUE(contextInfo, NS_ERROR_OUT_OF_MEMORY);
              contextInfo->SetStringValue("position", position);
              mContextInfo.AppendObject(contextInfo);

              InsertNode(locationNode, newNode,
                         insertAfter ? eLocation_After: eLocation_Before,
                         getter_AddRefs(resNode));
            }
          }
        }
        rv = nsXFormsUtils::GetInstanceNodeForData(resNode, getter_AddRefs(instNode));
        NS_ENSURE_SUCCESS(rv, rv);

      // Step 8: Set indexes for repeats
      rv = RefreshRepeats(&cloneNodes);
      NS_ENSURE_SUCCESS(rv, rv);

    } else {
      // Delete
      // If there is no delete location, each node in the Node Set Binding
      // node-set is deleted, unless the node is the root document element of an
      // instance.
      //
      // If there is a delete location, the node at the delete location in the
      // Node Set Binding node-set is deleted, unless the node is the root
      // document element of an instance.
      PRBool didDelete = PR_FALSE;

      PRUint32 deleteIndex, deleteCount;

      if (!locationNode) {
        // Delete all the nodes in the node-set.
        deleteIndex = 0;
        deleteCount = nodesetSize;
      } else {
        // Delete the node at the delete location.
        deleteIndex = atInt - 1;
        deleteCount = atInt;
      }
      // Context Info: 'deleted-nodes'
      nsCOMPtr<nsXFormsContextInfo> contextInfo =
        new nsXFormsContextInfo(element);
      NS_ENSURE_TRUE(contextInfo, NS_ERROR_OUT_OF_MEMORY);
      contextInfo->SetNodesetValue("deleted-nodes", nodeset);
      mContextInfo.AppendObject(contextInfo);

      nodeset->SnapshotItem(deleteIndex, getter_AddRefs(locationNode));
      NS_ENSURE_STATE(locationNode);

      locationNode->GetOwnerDocument(getter_AddRefs(locationDoc));
      NS_ENSURE_STATE(locationDoc);

      rv = nsXFormsUtils::GetInstanceNodeForData(locationNode, getter_AddRefs(instNode));
      NS_ENSURE_SUCCESS(rv, rv);

      locationDoc->GetDocumentElement(getter_AddRefs(locationDocElement));
      while ((deleteIndex < deleteCount) && locationNode) {
        // Delete the node(s) unless the delete location is the root document
        // element of an instance.
        PRUint16 locationNodeType;
        locationNode->GetNodeType(&locationNodeType);
        if (locationNodeType == nsIDOMNode::ATTRIBUTE_NODE) {
          nsCOMPtr<nsIDOMElement> ownerElement;
          nsCOMPtr<nsIDOMAttr> attrNode(do_QueryInterface(locationNode));
          attrNode->GetOwnerElement(getter_AddRefs(ownerElement));
          NS_ENSURE_STATE(ownerElement);

          nsCOMPtr<nsIDOMAttr> resAttr;
          ownerElement->RemoveAttributeNode(attrNode, getter_AddRefs(resAttr));
          resNode = locationNode;

          // Deleted at least one node so delete will not terminate.
          didDelete = PR_TRUE;
        } else {
          if (!SameCOMIdentity(locationNode, locationDocElement)) {
            locationNode->GetParentNode(getter_AddRefs(parentNode));
            NS_ENSURE_STATE(parentNode);

            rv = parentNode->RemoveChild(locationNode, getter_AddRefs(resNode));
            NS_ENSURE_SUCCESS(rv, rv);

            // Deleted at least one node so delete will not terminate.
            didDelete = PR_TRUE;
          }
        }
        // Get the next node in the node-set.
        ++deleteIndex;
        nodeset->SnapshotItem(deleteIndex, getter_AddRefs(locationNode));
      }

      // The delete action is terminated with no effect if no node is deleted.
      if (!didDelete)
        return NS_OK;
    }
    NS_ENSURE_STATE(resNode);

    // Dispatch xforms-insert/delete event to the instance node we have modified
    // data for
    rv = nsXFormsUtils::DispatchEvent(instNode,
                                      mIsInsert ? eEvent_Insert : eEvent_Delete,
                                      nsnull, nsnull, &mContextInfo);
    NS_ENSURE_SUCCESS(rv, rv);

    // Dispatch refreshing events to the model
    if (aParentAction) {
      aParentAction->SetRebuild(model, PR_TRUE);
      aParentAction->SetRecalculate(model, PR_TRUE);
      aParentAction->SetRevalidate(model, PR_TRUE);
      aParentAction->SetRefresh(model, PR_TRUE);
    } else {
      rv = model->RequestRebuild();
      NS_ENSURE_SUCCESS(rv, rv);
      rv = model->RequestRecalculate();
      NS_ENSURE_SUCCESS(rv, rv);
      rv = model->RequestRevalidate();
      NS_ENSURE_SUCCESS(rv, rv);
      rv = model->RequestRefresh();
      NS_ENSURE_SUCCESS(rv, rv);
    }

    // Repeat this action if it can iterate and if it uses the `while`
    // attribute (the expression of which must have evaluated to true to
    // arrive here).
    if (!CanIterate() || !usesWhile) {
      return NS_OK;
    }

    // See if we've exceeded our time limit, and if so, prompt the user to
    // determine if she wants to cancel the loop.
    LL_SUB(runTime, PR_Now(), start);
    if (microseconds <= 0 || runTime < microseconds) {
      continue;
    }

    // The remaining part of the loop prompts the user about cancelling the
    // loop, and is only executed if we've gone over the time limit.
    PRBool stopWaiting = nsXFormsUtils::AskStopWaiting(element);

    if (stopWaiting) {
      // Stop the loop
      return NS_OK;
    } else {
      start = PR_Now();
    }
  }

  return NS_OK;
}


nsresult
nsXFormsInsertDeleteElement::GetFirstNodeOfType(nsCOMArray<nsIDOMNode> *aNodes,
                                                PRUint16 aNodeType,
                                                nsIDOMNode **aResult)
{
  nsCOMPtr<nsIDOMNode> currentNode;

  for (PRInt32 i = 0; i < aNodes->Count(); ++i) {
    currentNode = aNodes->ObjectAt(i);
    PRUint16 nodeType;
    currentNode->GetNodeType(&nodeType);
    if (nodeType == aNodeType) {
      NS_IF_ADDREF(*aResult = currentNode);
      break;
    }
  }

  return NS_OK;
}

nsresult
nsXFormsInsertDeleteElement::InsertNode(nsIDOMNode *aTargetNode,
                                        nsIDOMNode *aNewNode,
                                        Location   aLocation,
                                        nsIDOMNode **aResNode)
{
  NS_ENSURE_ARG(aTargetNode);
  NS_ENSURE_ARG(aNewNode);
  NS_ENSURE_ARG_POINTER(aResNode);

  // Make sure the result node is null in case we encounter a condition
  // where the node cannot be inserted and is skipped.
  *aResNode = nsnull;

  // Step 7 - The new node is inserted at the target location depending on its
  // node type. If the cloned node is a duplicate of another attribute in its
  // parent element, then the duplicate attribute is first removed. If a cloned
  // node cannot be placed at the target location due to a node type conflict,
  // then the insertion for that particular clone node is ignored.
  nsCOMPtr<nsIDOMNode> resNode;
  
  PRUint16 targetNodeType, newNodeType;
  aTargetNode->GetNodeType(&targetNodeType);
  aNewNode->GetNodeType(&newNodeType);
  
  if (newNodeType == nsIDOMNode::ATTRIBUTE_NODE) {
    // Can add an attribute to an element node or the owning element
    // of an attribute node.
    nsCOMPtr<nsIDOMElement> ownerElement;

    if (targetNodeType == nsIDOMNode::ELEMENT_NODE) {
      ownerElement = do_QueryInterface(aTargetNode);
    } else if (targetNodeType == nsIDOMNode::ATTRIBUTE_NODE) {
      nsCOMPtr<nsIDOMAttr> targetAttrNode(do_QueryInterface(aTargetNode));
      targetAttrNode->GetOwnerElement(getter_AddRefs(ownerElement));
    }
    NS_ENSURE_STATE(ownerElement);

    // Check for a duplicate attribute.
    nsAutoString attrNamespace, attrName, attrValue;
    aNewNode->GetNamespaceURI(attrNamespace);
    aNewNode->GetLocalName(attrName);
    aNewNode->GetNodeValue(attrValue);

    PRBool hasAttribute = PR_FALSE;
    ownerElement->HasAttributeNS(attrNamespace, attrName, &hasAttribute);
    if (hasAttribute) {
      ownerElement->RemoveAttributeNS(attrNamespace, attrName);
    }
    ownerElement->SetAttributeNS(attrNamespace, attrName, attrValue);
    resNode = aTargetNode;
    resNode.swap(*aResNode);

  } else {
    // New node will be inserted at location aLocation.
    nsCOMPtr<nsIDOMNode> targetNode = aTargetNode;

    nsCOMPtr<nsIDOMNode> parentNode;
    targetNode->GetParentNode(getter_AddRefs(parentNode));
    NS_ENSURE_STATE(parentNode);

    if (aLocation == eLocation_FirstChild) {
      aTargetNode->AppendChild(aNewNode, getter_AddRefs(resNode));
      resNode.swap(*aResNode);
    } else {
      if (aLocation == eLocation_After) {
        // If we're at the end of the nodeset, this returns nsnull, which is
        // fine, because InsertBefore then inserts at the end of the nodeset.
        aTargetNode->GetNextSibling(getter_AddRefs(targetNode));
      }
      parentNode->InsertBefore(aNewNode, targetNode,
                               getter_AddRefs(resNode));
      resNode.swap(*aResNode);
    }
  }
  
  return NS_OK;
}

nsresult
nsXFormsInsertDeleteElement::RefreshRepeats(nsCOMArray<nsIDOMNode> *aNodes)
{
  // XXXbeaufour: only check repeats belonging to the same model...
  // possibly use mFormControls? Should be quicker than searching through
  // entire document!! mModel->GetControls("repeat"); Would also possibly
  // save a QI?

  nsCOMPtr<nsIDOMDocument> document;

  nsresult rv = mElement->GetOwnerDocument(getter_AddRefs(document));
  NS_ENSURE_STATE(document);

  nsCOMPtr<nsIDOMNodeList> repeatNodes;
  document->GetElementsByTagNameNS(NS_LITERAL_STRING(NS_NAMESPACE_XFORMS),
                                   NS_LITERAL_STRING("repeat"),
                                   getter_AddRefs(repeatNodes));
  NS_ENSURE_STATE(repeatNodes);

  // work over each node and if the node contains the inserted element
  PRUint32 nodeCount;
  rv = repeatNodes->GetLength(&nodeCount);
  NS_ENSURE_SUCCESS(rv, rv);

  for (PRUint32 node = 0; node < nodeCount; ++node) {
    nsCOMPtr<nsIDOMNode> repeatNode;

    rv = repeatNodes->Item(node, getter_AddRefs(repeatNode));
    nsCOMPtr<nsIXFormsRepeatElement> repeatEl(do_QueryInterface(repeatNode));
    NS_ENSURE_STATE(repeatEl);

    for (PRInt32 i = 0; i < aNodes->Count(); ++i) {
      nsCOMPtr<nsIDOMNode> newNode = aNodes->ObjectAt(i);
      rv = repeatEl->HandleNodeInsert(newNode);
      NS_ENSURE_SUCCESS(rv, rv);
    }
  }

  return NS_OK;
}
 

NS_HIDDEN_(nsresult)
NS_NewXFormsInsertElement(nsIXTFElement **aResult)
{
  *aResult = new nsXFormsInsertDeleteElement(PR_TRUE);
  if (!*aResult)
    return NS_ERROR_OUT_OF_MEMORY;

  NS_ADDREF(*aResult);
  return NS_OK;
}


NS_HIDDEN_(nsresult)
NS_NewXFormsDeleteElement(nsIXTFElement **aResult)
{
  *aResult = new nsXFormsInsertDeleteElement(PR_FALSE);
  if (!*aResult)
    return NS_ERROR_OUT_OF_MEMORY;

  NS_ADDREF(*aResult);
  return NS_OK;
}