/*
* 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 1.20 2005/03/23 17:54:04 ytalwar Exp $
*/
package org.apache.xalan.xsltc.compiler;
import org.apache.bcel.generic.BranchHandle;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.GOTO;
import org.apache.bcel.generic.IFEQ;
import org.apache.bcel.generic.IFGE;
import org.apache.bcel.generic.IFGT;
import org.apache.bcel.generic.ILOAD;
import org.apache.bcel.generic.INVOKEINTERFACE;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.ISTORE;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.LocalVariableGen;
import org.apache.bcel.generic.PUSH;
import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.ErrorMsg;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.NodeSetType;
import org.apache.xalan.xsltc.compiler.util.StringType;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xalan.xsltc.compiler.util.Util;
import org.apache.xml.dtm.Axis;
import org.apache.xml.utils.XML11Char;
/**
* @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 <xsl:key> 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 (!XML11Char.isXML11ValidQName(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 <xsl:key> 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);
}
}