rangeimpl.java

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            if (isAncestorOf(node, fEndContainer)) {
                fEndContainer = parent;
                fEndOffset = indexOf( node, parent);
            }
        } 
        
    }
        
    //
    // Utility functions.
    //
    
    // parameters for traverseContents(int)
    //REVIST: use boolean, since there are only 2 now...
    static final int EXTRACT_CONTENTS = 1;
    static final int CLONE_CONTENTS = 2;
    static final int DELETE_CONTENTS = 3;
    
    /**
     * This is the master routine invoked to visit the nodes
     * selected by this range.  For each such node, different
     * actions are taken depending on the value of the
     * <code>how</code> argument.
     * 
     * @param how    Specifies what type of traversal is being
     *               requested (extract, clone, or delete).
     *               Legal values for this argument are:
     * 
     *               <ol>
     *               <li><code>EXTRACT_CONTENTS</code> - will produce
     *               a document fragment containing the range's content.
     *               Partially selected nodes are copied, but fully
     *               selected nodes are moved.
     *               
     *               <li><code>CLONE_CONTENTS</code> - will leave the
     *               context tree of the range undisturbed, but sill
     *               produced cloned content in a document fragment
     *               
     *               <li><code>DELETE_CONTENTS</code> - will delete from
     *               the context tree of the range, all fully selected
     *               nodes.
     *               </ol>
     * 
     * @return Returns a document fragment containing any
     *         copied or extracted nodes.  If the <code>how</code>
     *         parameter was <code>DELETE_CONTENTS</code>, the
     *         return value is null.
     */
    private DocumentFragment traverseContents( int how )
        throws DOMException
    {
        if (fStartContainer == null || fEndContainer == null) {
            return null; // REVIST: Throw exception?
        }
        
        //Check for a detached range.
        if( fDetach) {
            throw new DOMException(
                DOMException.INVALID_STATE_ERR, 
                DOMMessageFormatter.formatMessage(DOMMessageFormatter.DOM_DOMAIN, "INVALID_STATE_ERR", null));
        }

        /*
          Traversal is accomplished by first determining the
          relationship between the endpoints of the range.
          For each of four significant relationships, we will
          delegate the traversal call to a method that 
          can make appropriate assumptions.
         */

        // case 1: same container
        if ( fStartContainer == fEndContainer )
            return traverseSameContainer( how );


        // case 2: Child C of start container is ancestor of end container 
        // This can be quickly tested by walking the parent chain of 
        // end container
        int endContainerDepth = 0;
        for ( Node c = fEndContainer, p = c.getParentNode();
             p != null;
             c = p, p = p.getParentNode())
        {
            if (p == fStartContainer)
                return traverseCommonStartContainer( c, how );
            ++endContainerDepth;
        }

        // case 3: Child C of container B is ancestor of A
        // This can be quickly tested by walking the parent chain of A
        int startContainerDepth = 0;
        for ( Node c = fStartContainer, p = c.getParentNode();
             p != null;
             c = p, p = p.getParentNode())
        {
            if (p == fEndContainer)
                return traverseCommonEndContainer( c, how );
            ++startContainerDepth;
        }

        // case 4: There is a common ancestor container.  Find the
        // ancestor siblings that are children of that container.
        int depthDiff = startContainerDepth - endContainerDepth;

        Node startNode = fStartContainer;
        while (depthDiff > 0) {
            startNode = startNode.getParentNode();
            depthDiff--;
        }

        Node endNode = fEndContainer;
        while (depthDiff < 0) {
            endNode = endNode.getParentNode();
            depthDiff++;
        }

        // ascend the ancestor hierarchy until we have a common parent.
        for( Node sp = startNode.getParentNode(), ep = endNode.getParentNode();
             sp!=ep; 
             sp = sp.getParentNode(), ep = ep.getParentNode() )
        {
            startNode = sp;
            endNode = ep;
        }
        return traverseCommonAncestors( startNode, endNode, how );
    }
    
    /**
     * Visits the nodes selected by this range when we know
     * a-priori that the start and end containers are the same.
     * This method is invoked by the generic <code>traverse</code>
     * method.
     * 
     * @param how    Specifies what type of traversal is being
     *               requested (extract, clone, or delete).
     *               Legal values for this argument are:
     *               
     *               <ol>
     *               <li><code>EXTRACT_CONTENTS</code> - will produce
     *               a document fragment containing the range's content.
     *               Partially selected nodes are copied, but fully
     *               selected nodes are moved.
     *               
     *               <li><code>CLONE_CONTENTS</code> - will leave the
     *               context tree of the range undisturbed, but sill
     *               produced cloned content in a document fragment
     *               
     *               <li><code>DELETE_CONTENTS</code> - will delete from
     *               the context tree of the range, all fully selected
     *               nodes.
     *               </ol>
     * 
     * @return Returns a document fragment containing any
     *         copied or extracted nodes.  If the <code>how</code>
     *         parameter was <code>DELETE_CONTENTS</code>, the
     *         return value is null.
     */
    private DocumentFragment traverseSameContainer( int how )
    {
        DocumentFragment frag = null;
        if ( how!=DELETE_CONTENTS)
            frag = fDocument.createDocumentFragment();

        // If selection is empty, just return the fragment
        if ( fStartOffset==fEndOffset )
            return frag;

        // Text node needs special case handling
        if ( fStartContainer.getNodeType()==Node.TEXT_NODE )
        {
            // get the substring
            String s = fStartContainer.getNodeValue();
            String sub = s.substring( fStartOffset, fEndOffset );

            // set the original text node to its new value
            if ( how != CLONE_CONTENTS )
            {
                ((TextImpl)fStartContainer).deleteData(fStartOffset,
                     fEndOffset-fStartOffset) ;
                // Nothing is partially selected, so collapse to start point
                collapse( true );
            }
            if ( how==DELETE_CONTENTS)
                return null;
            frag.appendChild( fDocument.createTextNode(sub) );
            return frag;
        }

        // Copy nodes between the start/end offsets.
        Node n = getSelectedNode( fStartContainer, fStartOffset );
        int cnt = fEndOffset - fStartOffset;
        while( cnt > 0 )
        {
            Node sibling = n.getNextSibling();
            Node xferNode = traverseFullySelected( n, how );
            if ( frag!=null )
                frag.appendChild( xferNode );
            --cnt;
            n = sibling;
        }

        // Nothing is partially selected, so collapse to start point
        if ( how != CLONE_CONTENTS )
            collapse( true );
        return frag;
    }

    /**
     * Visits the nodes selected by this range when we know
     * a-priori that the start and end containers are not the
     * same, but the start container is an ancestor of the
     * end container. This method is invoked by the generic 
     * <code>traverse</code> method.
     * 
     * @param endAncestor
     *               The ancestor of the end container that is a direct child
     *               of the start container.
     * 
     * @param how    Specifies what type of traversal is being
     *               requested (extract, clone, or delete).
     *               Legal values for this argument are:
     *               
     *               <ol>
     *               <li><code>EXTRACT_CONTENTS</code> - will produce
     *               a document fragment containing the range's content.
     *               Partially selected nodes are copied, but fully
     *               selected nodes are moved.
     *               
     *               <li><code>CLONE_CONTENTS</code> - will leave the
     *               context tree of the range undisturbed, but sill
     *               produced cloned content in a document fragment
     *               
     *               <li><code>DELETE_CONTENTS</code> - will delete from
     *               the context tree of the range, all fully selected
     *               nodes.
     *               </ol>
     * 
     * @return Returns a document fragment containing any
     *         copied or extracted nodes.  If the <code>how</code>
     *         parameter was <code>DELETE_CONTENTS</code>, the
     *         return value is null.
     */
    private DocumentFragment 
        traverseCommonStartContainer( Node endAncestor, int how )
    {
        DocumentFragment frag = null;
        if ( how!=DELETE_CONTENTS)
            frag = fDocument.createDocumentFragment();
        Node n = traverseRightBoundary( endAncestor, how );
        if ( frag!=null )
            frag.appendChild( n );

        int endIdx = indexOf( endAncestor, fStartContainer );
        int cnt = endIdx - fStartOffset;
        if ( cnt <=0 )
        {
            // Collapse to just before the endAncestor, which 
            // is partially selected.
            if ( how != CLONE_CONTENTS )
            {
                setEndBefore( endAncestor );
                collapse( false );
            }
            return frag;
        }

        n = endAncestor.getPreviousSibling();
        while( cnt > 0 )
        {
            Node sibling = n.getPreviousSibling();
            Node xferNode = traverseFullySelected( n, how );
            if ( frag!=null )
                frag.insertBefore( xferNode, frag.getFirstChild() );
            --cnt;
            n = sibling;
        }
        // Collapse to just before the endAncestor, which 
        // is partially selected.
        if ( how != CLONE_CONTENTS )
        {
            setEndBefore( endAncestor );
            collapse( false );
        }
        return frag;
    }
    
    /**
     * Visits the nodes selected by this range when we know
     * a-priori that the start and end containers are not the
     * same, but the end container is an ancestor of the
     * start container. This method is invoked by the generic
     * <code>traverse</code> method.
     * 
     * @param startAncestor
     *               The ancestor of the start container that is a direct
     *               child of the end container.
     * 
     * @param how    Specifies what type of traversal is being
     *               requested (extract, clone, or delete).
     *               Legal values for this argument are:
     *               
     *               <ol>
     *               <li><code>EXTRACT_CONTENTS</code> - will produce
     *               a document fragment containing the range's content.
     *               Partially selected nodes are copied, but fully
     *               selected nodes are moved.
     *               
     *               <li><code>CLONE_CONTENTS</code> - will leave the
     *               context tree of the range undisturbed, but sill
     *               produced cloned content in a document fragment
     *               
     *               <li><code>DELETE_CONTENTS</code> - will delete from
     *               the context tree of the range, all fully selected
     *               nodes.
     *               </ol>
     * 
     * @return Returns a document fragment containing any
     *         copied or extracted nodes.  If the <code>how</code>
     *         parameter was <code>DELETE_CONTENTS</code>, the
     *         return value is null.
     */
    private DocumentFragment 
        traverseCommonEndContainer( Node startAncestor, int how )
    {
        DocumentFragment frag = null;
        if ( how!=DELETE_CONTENTS)
            frag = fDocument.createDocumentFragment();
        Node n = traverseLeftBoundary( startAncestor, how );
        if ( frag!=null )
            frag.appendChild( n );
        int startIdx = indexOf( startAncestor, fEndContainer );
        ++startIdx;  // Because we already traversed it....

        int cnt = fEndOffset - startIdx;
        n = startAncestor.getNextSibling();
        while( cnt > 0 )
        {
            Node sibling = n.getNextSibling();
            Node xferNode = traverseFullySelected( n, how );
            if ( frag!=null )
                frag.appendChild( xferNode );
            --cnt;
            n = sibling;
        }

        if ( how != CLONE_CONTENTS )