/* * Copyright 2001-2004 The Apache Software Foundation. * * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /* * $Id: Key.java,v 1.18 2004/02/24 03:55:47 zongaro Exp $ */ package com.sun.org.apache.xalan.internal.xsltc.compiler; import com.sun.org.apache.bcel.internal.generic.BranchHandle; import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen; import com.sun.org.apache.bcel.internal.generic.GOTO; import com.sun.org.apache.bcel.internal.generic.IFEQ; import com.sun.org.apache.bcel.internal.generic.IFGE; import com.sun.org.apache.bcel.internal.generic.IFGT; import com.sun.org.apache.bcel.internal.generic.ILOAD; import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE; import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL; import com.sun.org.apache.bcel.internal.generic.ISTORE; import com.sun.org.apache.bcel.internal.generic.InstructionHandle; import com.sun.org.apache.bcel.internal.generic.InstructionList; import com.sun.org.apache.bcel.internal.generic.LocalVariableGen; import com.sun.org.apache.bcel.internal.generic.PUSH; import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator; import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg; import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator; import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeSetType; import com.sun.org.apache.xalan.internal.xsltc.compiler.util.StringType; import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type; import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError; import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util; import com.sun.org.apache.xalan.internal.xsltc.dom.Axis; import com.sun.org.apache.xml.internal.utils.XMLChar; /** * @author Morten Jorgensen * @author Santiago Pericas-Geertsen */ final class Key extends TopLevelElement { /** * The name of this key as defined in xsl:key. */ private QName _name; /** * The pattern to match starting at the root node. */ private Pattern _match; /** * The expression that generates the values for this key. */ private Expression _use; /** * The type of the _use expression. */ private Type _useType; /** * Parse the element and attributes * @param parser A reference to the stylesheet parser */ public void parseContents(Parser parser) { // Get the required attributes and parser XPath expressions final String name = getAttribute("name"); if (!XMLChar.isValidQName(name)){ ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, name, this); parser.reportError(Constants.ERROR, err); } _name = parser.getQNameIgnoreDefaultNs(name); _match = parser.parsePattern(this, "match", null); _use = parser.parseExpression(this, "use", null); // Make sure required attribute(s) have been set if (_name == null) { reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "name"); return; } if (_match.isDummy()) { reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "match"); return; } if (_use.isDummy()) { reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "use"); return; } } /** * Returns a String-representation of this key's name * @return The key's name (from the elements 'name' attribute). */ public String getName() { return _name.toString(); } public Type typeCheck(SymbolTable stable) throws TypeCheckError { // Type check match pattern _match.typeCheck(stable); // Cast node values to string values (except for nodesets) _useType = _use.typeCheck(stable); if (_useType instanceof StringType == false && _useType instanceof NodeSetType == false) { _use = new CastExpr(_use, Type.String); } return Type.Void; } /** * This method is called if the "use" attribute of the key contains a * node set. In this case we must traverse all nodes in the set and * create one entry in this key's index for each node in the set. */ public void traverseNodeSet(ClassGenerator classGen, MethodGenerator methodGen, int buildKeyIndex) { final ConstantPoolGen cpg = classGen.getConstantPool(); final InstructionList il = methodGen.getInstructionList(); // DOM.getStringValueX(nodeIndex) => String final int getNodeValue = cpg.addInterfaceMethodref(DOM_INTF, GET_NODE_VALUE, "(I)"+STRING_SIG); final int getNodeIdent = cpg.addInterfaceMethodref(DOM_INTF, "getNodeIdent", "(I)"+NODE_SIG); // AbstractTranslet.SetKeyIndexDom(name, Dom) => void final int keyDom = cpg.addMethodref(TRANSLET_CLASS, "setKeyIndexDom", "("+STRING_SIG+DOM_INTF_SIG+")V"); // This variable holds the id of the node we found with the "match" // attribute of xsl:key. This is the id we store, with the value we // get from the nodes we find here, in the index for this key. final LocalVariableGen parentNode = methodGen.addLocalVariable("parentNode", Util.getJCRefType("I"), il.getEnd(), null); // Get the 'parameter' from the stack and store it in a local var. il.append(new ISTORE(parentNode.getIndex())); il.append(methodGen.loadDOM()); il.append(new ILOAD(parentNode.getIndex())); il.append(new INVOKEINTERFACE(getNodeIdent, 2)); il.append(new ISTORE(parentNode.getIndex())); // Save current node and current iterator on the stack il.append(methodGen.loadCurrentNode()); il.append(methodGen.loadIterator()); // Overwrite current iterator with one that gives us only what we want _use.translate(classGen, methodGen); _use.startIterator(classGen, methodGen); il.append(methodGen.storeIterator()); final BranchHandle nextNode = il.append(new GOTO(null)); final InstructionHandle loop = il.append(NOP); // Prepare to call buildKeyIndex(String name, int node, String value); il.append(classGen.loadTranslet()); il.append(new PUSH(cpg, _name.toString())); il.append(new ILOAD(parentNode.getIndex())); // Now get the node value and feck it on the parameter stack il.append(methodGen.loadDOM()); il.append(methodGen.loadCurrentNode()); il.append(new INVOKEINTERFACE(getNodeValue, 2)); // Finally do the call to add an entry in the index for this key. il.append(new INVOKEVIRTUAL(buildKeyIndex)); il.append(classGen.loadTranslet()); il.append(new PUSH(cpg, getName())); il.append(methodGen.loadDOM()); il.append(new INVOKEVIRTUAL(keyDom)); nextNode.setTarget(il.append(methodGen.loadIterator())); il.append(methodGen.nextNode()); il.append(DUP); il.append(methodGen.storeCurrentNode()); il.append(new IFGE(loop)); // Go on to next matching node.... // Restore current node and current iterator from the stack il.append(methodGen.storeIterator()); il.append(methodGen.storeCurrentNode()); } /** * Gather all nodes that match the expression in the attribute "match" * and add one (or more) entries in this key's index. */ public void translate(ClassGenerator classGen, MethodGenerator methodGen) { final ConstantPoolGen cpg = classGen.getConstantPool(); final InstructionList il = methodGen.getInstructionList(); final int current = methodGen.getLocalIndex("current"); // AbstractTranslet.buildKeyIndex(name,node_id,value) => void final int key = cpg.addMethodref(TRANSLET_CLASS, "buildKeyIndex", "("+STRING_SIG+"I"+OBJECT_SIG+")V"); // AbstractTranslet.SetKeyIndexDom(name, Dom) => void final int keyDom = cpg.addMethodref(TRANSLET_CLASS, "setKeyIndexDom", "("+STRING_SIG+DOM_INTF_SIG+")V"); final int getNodeIdent = cpg.addInterfaceMethodref(DOM_INTF, "getNodeIdent", "(I)"+NODE_SIG); // DOM.getAxisIterator(root) => NodeIterator final int git = cpg.addInterfaceMethodref(DOM_INTF, "getAxisIterator", "(I)"+NODE_ITERATOR_SIG); il.append(methodGen.loadCurrentNode()); il.append(methodGen.loadIterator()); // Get an iterator for all nodes in the DOM il.append(methodGen.loadDOM()); il.append(new PUSH(cpg,Axis.DESCENDANT)); il.append(new INVOKEINTERFACE(git, 2)); // Reset the iterator to start with the root node il.append(methodGen.loadCurrentNode()); il.append(methodGen.setStartNode()); il.append(methodGen.storeIterator()); // Loop for traversing all nodes in the DOM final BranchHandle nextNode = il.append(new GOTO(null)); final InstructionHandle loop = il.append(NOP); // Check if the current node matches the pattern in "match" il.append(methodGen.loadCurrentNode()); _match.translate(classGen, methodGen); _match.synthesize(classGen, methodGen); // Leaves 0 or 1 on stack final BranchHandle skipNode = il.append(new IFEQ(null)); // If this is a node-set we must go through each node in the set if (_useType instanceof NodeSetType) { // Pass current node as parameter (we're indexing on that node) il.append(methodGen.loadCurrentNode()); traverseNodeSet(classGen, methodGen, key); } else { il.append(classGen.loadTranslet()); il.append(DUP); il.append(new PUSH(cpg, _name.toString())); il.append(DUP_X1); il.append(methodGen.loadCurrentNode()); _use.translate(classGen, methodGen); il.append(SWAP); il.append(methodGen.loadDOM()); il.append(SWAP); il.append(new INVOKEINTERFACE(getNodeIdent, 2)); il.append(SWAP); il.append(new INVOKEVIRTUAL(key)); il.append(methodGen.loadDOM()); il.append(new INVOKEVIRTUAL(keyDom)); } // Get the next node from the iterator and do loop again... final InstructionHandle skip = il.append(NOP); il.append(methodGen.loadIterator()); il.append(methodGen.nextNode()); il.append(DUP); il.append(methodGen.storeCurrentNode()); il.append(new IFGT(loop)); // Restore current node and current iterator from the stack il.append(methodGen.storeIterator()); il.append(methodGen.storeCurrentNode()); nextNode.setTarget(skip); skipNode.setTarget(skip); } }