/*
* 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: AncestorPattern.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.IFLT;
import org.apache.bcel.generic.ILOAD;
import org.apache.bcel.generic.INVOKEINTERFACE;
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.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.xalan.xsltc.compiler.util.Util;
/**
* @author Jacek Ambroziak
* @author Santiago Pericas-Geertsen
* @author Erwin Bolwidt <ejb@klomp.org>
*/
final class AncestorPattern extends RelativePathPattern {
private final Pattern _left; // may be null
private final RelativePathPattern _right;
private InstructionHandle _loop;
public AncestorPattern(RelativePathPattern right) {
this(null, right);
}
public AncestorPattern(Pattern left, RelativePathPattern right) {
_left = left;
(_right = right).setParent(this);
if (left != null) {
left.setParent(this);
}
}
public InstructionHandle getLoopHandle() {
return _loop;
}
public void setParser(Parser parser) {
super.setParser(parser);
if (_left != null) {
_left.setParser(parser);
}
_right.setParser(parser);
}
public boolean isWildcard() {
//!!! can be wildcard
return false;
}
public StepPattern getKernelPattern() {
return _right.getKernelPattern();
}
public void reduceKernelPattern() {
_right.reduceKernelPattern();
}
public Type typeCheck(SymbolTable stable) throws TypeCheckError {
if (_left != null) {
_left.typeCheck(stable);
}
return _right.typeCheck(stable);
}
public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
InstructionHandle parent;
final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
/*
* The scope of this local var must be the entire method since
* a another pattern may decide to jump back into the loop
*/
final LocalVariableGen local =
methodGen.addLocalVariable2("app", Util.getJCRefType(NODE_SIG),
il.getEnd());
final org.apache.bcel.generic.Instruction loadLocal =
new ILOAD(local.getIndex());
final org.apache.bcel.generic.Instruction storeLocal =
new ISTORE(local.getIndex());
if (_right instanceof StepPattern) {
il.append(DUP);
il.append(storeLocal);
_right.translate(classGen, methodGen);
il.append(methodGen.loadDOM());
il.append(loadLocal);
}
else {
_right.translate(classGen, methodGen);
if (_right instanceof AncestorPattern) {
il.append(methodGen.loadDOM());
il.append(SWAP);
}
}
if (_left != null) {
final int getParent = cpg.addInterfaceMethodref(DOM_INTF,
GET_PARENT,
GET_PARENT_SIG);
parent = il.append(new INVOKEINTERFACE(getParent, 2));
il.append(DUP);
il.append(storeLocal);
_falseList.add(il.append(new IFLT(null)));
il.append(loadLocal);
_left.translate(classGen, methodGen);
final SyntaxTreeNode p = getParent();
if (p == null || p instanceof Instruction ||
p instanceof TopLevelElement)
{
// do nothing
}
else {
il.append(loadLocal);
}
final BranchHandle exit = il.append(new GOTO(null));
_loop = il.append(methodGen.loadDOM());
il.append(loadLocal);
local.setEnd(_loop);
il.append(new GOTO(parent));
exit.setTarget(il.append(NOP));
_left.backPatchFalseList(_loop);
_trueList.append(_left._trueList);
}
else {
il.append(POP2);
}
/*
* If _right is an ancestor pattern, backpatch this pattern's false
* list to the loop that searches for more ancestors.
*/
if (_right instanceof AncestorPattern) {
final AncestorPattern ancestor = (AncestorPattern) _right;
_falseList.backPatch(ancestor.getLoopHandle()); // clears list
}
_trueList.append(_right._trueList);
_falseList.append(_right._falseList);
}
public String toString() {
return "AncestorPattern(" + _left + ", " + _right + ')';
}
}