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 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 /**

  * Implementation of an XPath NodeSet

  */

 #ifndef txNodeSet_h__

 #define txNodeSet_h__

 #include "txExprResult.h"

 #include "nsError.h"

 #include "txXPathNode.h"

 class txNodeSet : public txAExprResult

 {

 public:

     /**

      * Creates a new empty NodeSet

      */

     txNodeSet(txResultRecycler* aRecycler);

     /**

      * Creates a new NodeSet with one node.

      */

     txNodeSet(const txXPathNode& aNode, txResultRecycler* aRecycler);

     /**

      * Creates a new txNodeSet, copying the node references from the source

      * NodeSet.

      */

     txNodeSet(const txNodeSet& aSource, txResultRecycler* aRecycler);

     /**

      * Destructor for txNodeSet, deletes the nodes.

      */

     virtual ~txNodeSet();

     /**

      * Adds the specified txXPathNode to this NodeSet if it is not already

      * in this NodeSet. The node is inserted according to document order.

      *

      * @param  aNode the txXPathNode to add to the NodeSet

      * @return errorcode.

      */

     nsresult add(const txXPathNode& aNode);

     /**

      * Adds the nodes in specified NodeSet to this NodeSet. The resulting

      * NodeSet is sorted in document order and does not contain any duplicate

      * nodes.

      *

      * @param  aNodes the NodeSet to add, must be in document order.

      * @return errorcode.

      */

     nsresult add(const txNodeSet& aNodes);

     nsresult addAndTransfer(txNodeSet* aNodes);

     /**

      * Append API

      * These functions should be used with care.

      * They are intended to be used when the caller assures that the resulting

      * NodeSet remains in document order.

      * Abuse will break document order, and cause errors in the result.

      * These functions are significantly faster than the add API, as no

      * order info operations will be performed.

      */

     /**

      * Appends the specified Node to the end of this NodeSet

      * @param  aNode the Node to append to the NodeSet

      * @return errorcode.

      */

     nsresult append(const txXPathNode& aNode);

     /**

      * Appends the nodes in the specified NodeSet to the end of this NodeSet

      * @param  aNodes the NodeSet to append to the NodeSet

      * @return errorcode.

      */

     nsresult append(const txNodeSet& aNodes);

     /**

      * API to implement reverse axes in LocationStep.

      *

      * Before adding nodes to the nodeset for a reversed axis, call

      * setReverse(). This will make the append(aNode) and get() methods treat

      * the nodeset as required. Do only call append(aNode), get(), mark()

      * and sweep() while the nodeset is reversed.

      * Afterwards, call unsetReverse(). The nodes are stored in document

      * order internally.

      */

     void setReverse()

     {

         mDirection = -1;

     }

     void unsetReverse()

     {

         mDirection = 1;

     }

     /**

      * API to implement predicates in PredicateExpr

      *

      * mark(aIndex) marks the specified member of the nodeset.

      * sweep() clears all members of the nodeset that haven't been

      * marked before and clear the mMarks array.

      */

     nsresult mark(int32_t aIndex);

     nsresult sweep();

     /**

      * Removes all nodes from this nodeset

      */

     void clear();

     /**

      * Returns the index of the specified Node,

      * or -1 if the Node is not contained in the NodeSet

      * @param  aNode the Node to get the index for

      * @param  aStart index to start searching at

      * @return index of specified node or -1 if the node does not exist

      */

     int32_t indexOf(const txXPathNode& aNode, uint32_t aStart = 0) const;

     /**

      * Returns true if the specified Node is contained in the set.

      * @param  aNode the Node to search for

      * @return true if specified Node is contained in the NodeSet

      */

     bool contains(const txXPathNode& aNode) const

     {

         return indexOf(aNode) >= 0;

     }

     /**

      * Returns the Node at the specified node in this NodeSet.

      * @param  aIndex the node of the Node to return

      * @return Node at specified node

      */

     const txXPathNode& get(int32_t aIndex) const;

     /**

      * Returns true if there are no Nodes in the NodeSet.

      * @return true if there are no Nodes in the NodeSet.

      */

     bool isEmpty() const

     {

         return mStart ? mStart == mEnd : true;

     }

     /**

      * Returns the number of elements in the NodeSet

      * @return the number of elements in the NodeSet

      */

     int32_t size() const

     {

         return mStart ? mEnd - mStart : 0;

     }

     TX_DECL_EXPRRESULT

 private:

     /**

      * Ensure that this nodeset can take another aSize nodes.

      *

      * Changes mStart and mEnd as well as mBufferStart and mBufferEnd.

      */

     bool ensureGrowSize(int32_t aSize);

     /**

      * Finds position in the buffer where a node should be inserted

      * to keep the nodeset in document order. Searches the positions

      * aFirst-aLast, including aFirst, but not aLast.

      * @param  aNode   Node to find insert position for.

      * @param  aFirst  First item of the search range, included.

      * @param  aLast   Last item of the search range, excluded.

      * @param  aDupe   out-param. Will be set to true if the node already

      *                 exists in the NodeSet, false if it should be

      *                 inserted.

      * @return pointer where to insert the node. The node should be inserted

      *         before the given node. This value is always set, even if aNode

      *         already exists in the NodeSet

      */

     txXPathNode* findPosition(const txXPathNode& aNode, 

                               txXPathNode* aFirst,

                               txXPathNode* aLast, bool& aDupe) const;

     static void copyElements(txXPathNode* aDest, const txXPathNode* aStart,

                              const txXPathNode* aEnd);

     static void transferElements(txXPathNode* aDest, const txXPathNode* aStart,

                                  const txXPathNode* aEnd);

     static void destroyElements(const txXPathNode* aStart,

                                 const txXPathNode* aEnd)

     {

         while (aStart < aEnd) {

             aStart->~txXPathNode();

             ++aStart;

         }

     }

     typedef void (*transferOp) (txXPathNode* aDest, const txXPathNode* aStart,

                                 const txXPathNode* aEnd);

     typedef void (*destroyOp) (const txXPathNode* aStart,

                                const txXPathNode* aEnd);

     nsresult add(const txNodeSet& aNodes, transferOp aTransfer,

                  destroyOp aDestroy);

     txXPathNode *mStart, *mEnd, *mStartBuffer, *mEndBuffer;

     int32_t mDirection;

     // used for mark() and sweep() in predicates

     bool* mMarks;

 };

 #endif