/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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: ProcessingInstructionPattern.java 468650 2006-10-28 07:03:30Z minchau $
*/
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.IF_ICMPEQ;
import org.apache.bcel.generic.INVOKEINTERFACE;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.PUSH;
import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xml.dtm.Axis;
import org.apache.xml.dtm.DTM;
/**
* @author Morten Jorgensen
*/
final class ProcessingInstructionPattern extends StepPattern {
private String _name = null;
private boolean _typeChecked = false;
/**
* Handles calls with no parameter (current node is implicit parameter).
*/
public ProcessingInstructionPattern(String name) {
super(Axis.CHILD, DTM.PROCESSING_INSTRUCTION_NODE, null);
_name = name;
//if (_name.equals("*")) _typeChecked = true; no wildcard allowed!
}
/**
*
*/
public double getDefaultPriority() {
return (_name != null) ? 0.0 : -0.5;
}
public String toString() {
if (_predicates == null)
return "processing-instruction("+_name+")";
else
return "processing-instruction("+_name+")"+_predicates;
}
public void reduceKernelPattern() {
_typeChecked = true;
}
public boolean isWildcard() {
return false;
}
public Type typeCheck(SymbolTable stable) throws TypeCheckError {
if (hasPredicates()) {
// Type check all the predicates (e -> position() = e)
final int n = _predicates.size();
for (int i = 0; i < n; i++) {
final Predicate pred = (Predicate)_predicates.elementAt(i);
pred.typeCheck(stable);
}
}
return Type.NodeSet;
}
public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
// context node is on the stack
int gname = cpg.addInterfaceMethodref(DOM_INTF,
"getNodeName",
"(I)Ljava/lang/String;");
int cmp = cpg.addMethodref(STRING_CLASS,
"equals", "(Ljava/lang/Object;)Z");
// Push current node on the stack
il.append(methodGen.loadCurrentNode());
il.append(SWAP);
// Overwrite current node with matching node
il.append(methodGen.storeCurrentNode());
// If pattern not reduced then check kernel
if (!_typeChecked) {
il.append(methodGen.loadCurrentNode());
final int getType = cpg.addInterfaceMethodref(DOM_INTF,
"getExpandedTypeID",
"(I)I");
il.append(methodGen.loadDOM());
il.append(methodGen.loadCurrentNode());
il.append(new INVOKEINTERFACE(getType, 2));
il.append(new PUSH(cpg, DTM.PROCESSING_INSTRUCTION_NODE));
_falseList.add(il.append(new IF_ICMPEQ(null)));
}
// Load the requested processing instruction name
il.append(new PUSH(cpg, _name));
// Load the current processing instruction's name
il.append(methodGen.loadDOM());
il.append(methodGen.loadCurrentNode());
il.append(new INVOKEINTERFACE(gname, 2));
// Compare the two strings
il.append(new INVOKEVIRTUAL(cmp));
_falseList.add(il.append(new IFEQ(null)));
// Compile the expressions within the predicates
if (hasPredicates()) {
final int n = _predicates.size();
for (int i = 0; i < n; i++) {
Predicate pred = (Predicate)_predicates.elementAt(i);
Expression exp = pred.getExpr();
exp.translateDesynthesized(classGen, methodGen);
_trueList.append(exp._trueList);
_falseList.append(exp._falseList);
}
}
// Backpatch true list and restore current iterator/node
InstructionHandle restore;
restore = il.append(methodGen.storeCurrentNode());
backPatchTrueList(restore);
BranchHandle skipFalse = il.append(new GOTO(null));
// Backpatch false list and restore current iterator/node
restore = il.append(methodGen.storeCurrentNode());
backPatchFalseList(restore);
_falseList.add(il.append(new GOTO(null)));
// True list falls through
skipFalse.setTarget(il.append(NOP));
}
}