| /* |
| * reserved comment block |
| * DO NOT REMOVE OR ALTER! |
| */ |
| /* |
| * Copyright 2001-2005 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: ParentLocationPath.java,v 1.2.4.1 2005/09/12 10:56:30 pvedula Exp $ |
| */ |
| |
| package com.sun.org.apache.xalan.internal.xsltc.compiler; |
| |
| import com.sun.org.apache.bcel.internal.generic.ALOAD; |
| import com.sun.org.apache.bcel.internal.generic.ASTORE; |
| import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen; |
| import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE; |
| import com.sun.org.apache.bcel.internal.generic.INVOKESPECIAL; |
| import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL; |
| 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.NEW; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator; |
| import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator; |
| 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.xml.internal.dtm.Axis; |
| import com.sun.org.apache.xml.internal.dtm.DTM; |
| |
| /** |
| * @author Jacek Ambroziak |
| * @author Santiago Pericas-Geertsen |
| */ |
| final class ParentLocationPath extends RelativeLocationPath { |
| private Expression _step; |
| private final RelativeLocationPath _path; |
| private Type stype; |
| private boolean _orderNodes = false; |
| private boolean _axisMismatch = false; |
| |
| public ParentLocationPath(RelativeLocationPath path, Expression step) { |
| _path = path; |
| _step = step; |
| _path.setParent(this); |
| _step.setParent(this); |
| |
| if (_step instanceof Step) { |
| _axisMismatch = checkAxisMismatch(); |
| } |
| } |
| |
| public void setAxis(int axis) { |
| _path.setAxis(axis); |
| } |
| |
| public int getAxis() { |
| return _path.getAxis(); |
| } |
| |
| public RelativeLocationPath getPath() { |
| return(_path); |
| } |
| |
| public Expression getStep() { |
| return(_step); |
| } |
| |
| public void setParser(Parser parser) { |
| super.setParser(parser); |
| _step.setParser(parser); |
| _path.setParser(parser); |
| } |
| |
| public String toString() { |
| return "ParentLocationPath(" + _path + ", " + _step + ')'; |
| } |
| |
| public Type typeCheck(SymbolTable stable) throws TypeCheckError { |
| stype = _step.typeCheck(stable); |
| _path.typeCheck(stable); |
| |
| if (_axisMismatch) enableNodeOrdering(); |
| |
| return _type = Type.NodeSet; |
| } |
| |
| public void enableNodeOrdering() { |
| SyntaxTreeNode parent = getParent(); |
| if (parent instanceof ParentLocationPath) |
| ((ParentLocationPath)parent).enableNodeOrdering(); |
| else { |
| _orderNodes = true; |
| } |
| } |
| |
| /** |
| * This method is used to determine if this parent location path is a |
| * combination of two step's with axes that will create duplicate or |
| * unordered nodes. |
| */ |
| public boolean checkAxisMismatch() { |
| |
| int left = _path.getAxis(); |
| int right = ((Step)_step).getAxis(); |
| |
| if (((left == Axis.ANCESTOR) || (left == Axis.ANCESTORORSELF)) && |
| ((right == Axis.CHILD) || |
| (right == Axis.DESCENDANT) || |
| (right == Axis.DESCENDANTORSELF) || |
| (right == Axis.PARENT) || |
| (right == Axis.PRECEDING) || |
| (right == Axis.PRECEDINGSIBLING))) |
| return true; |
| |
| if ((left == Axis.CHILD) && |
| (right == Axis.ANCESTOR) || |
| (right == Axis.ANCESTORORSELF) || |
| (right == Axis.PARENT) || |
| (right == Axis.PRECEDING)) |
| return true; |
| |
| if ((left == Axis.DESCENDANT) || (left == Axis.DESCENDANTORSELF)) |
| return true; |
| |
| if (((left == Axis.FOLLOWING) || (left == Axis.FOLLOWINGSIBLING)) && |
| ((right == Axis.FOLLOWING) || |
| (right == Axis.PARENT) || |
| (right == Axis.PRECEDING) || |
| (right == Axis.PRECEDINGSIBLING))) |
| return true; |
| |
| if (((left == Axis.PRECEDING) || (left == Axis.PRECEDINGSIBLING)) && |
| ((right == Axis.DESCENDANT) || |
| (right == Axis.DESCENDANTORSELF) || |
| (right == Axis.FOLLOWING) || |
| (right == Axis.FOLLOWINGSIBLING) || |
| (right == Axis.PARENT) || |
| (right == Axis.PRECEDING) || |
| (right == Axis.PRECEDINGSIBLING))) |
| return true; |
| |
| if ((right == Axis.FOLLOWING) && (left == Axis.CHILD)) { |
| // Special case for '@*/following::*' expressions. The resulting |
| // iterator is initialised with the parent's first child, and this |
| // can cause duplicates in the output if the parent has more than |
| // one attribute that matches the left step. |
| if (_path instanceof Step) { |
| int type = ((Step)_path).getNodeType(); |
| if (type == DTM.ATTRIBUTE_NODE) return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| public void translate(ClassGenerator classGen, MethodGenerator methodGen) { |
| |
| // Compile path iterator |
| _path.translate(classGen, methodGen); // iterator on stack.... |
| |
| translateStep(classGen, methodGen); |
| } |
| |
| public void translateStep(ClassGenerator classGen, MethodGenerator methodGen) { |
| final ConstantPoolGen cpg = classGen.getConstantPool(); |
| final InstructionList il = methodGen.getInstructionList(); |
| |
| // Backwards branches are prohibited if an uninitialized object is |
| // on the stack by section 4.9.4 of the JVM Specification, 2nd Ed. |
| // We don't know whether this code might contain backwards branches |
| // so we mustn't create the new object until after we've created |
| // the suspect arguments to its constructor. Instead we calculate |
| // the values of the arguments to the constructor first, store them |
| // in temporary variables, create the object and reload the |
| // arguments from the temporaries to avoid the problem. |
| |
| LocalVariableGen pathTemp |
| = methodGen.addLocalVariable("parent_location_path_tmp1", |
| Util.getJCRefType(NODE_ITERATOR_SIG), |
| null, null); |
| pathTemp.setStart(il.append(new ASTORE(pathTemp.getIndex()))); |
| |
| _step.translate(classGen, methodGen); |
| LocalVariableGen stepTemp |
| = methodGen.addLocalVariable("parent_location_path_tmp2", |
| Util.getJCRefType(NODE_ITERATOR_SIG), |
| null, null); |
| stepTemp.setStart(il.append(new ASTORE(stepTemp.getIndex()))); |
| |
| // Create new StepIterator |
| final int initSI = cpg.addMethodref(STEP_ITERATOR_CLASS, |
| "<init>", |
| "(" |
| +NODE_ITERATOR_SIG |
| +NODE_ITERATOR_SIG |
| +")V"); |
| il.append(new NEW(cpg.addClass(STEP_ITERATOR_CLASS))); |
| il.append(DUP); |
| |
| pathTemp.setEnd(il.append(new ALOAD(pathTemp.getIndex()))); |
| stepTemp.setEnd(il.append(new ALOAD(stepTemp.getIndex()))); |
| |
| // Initialize StepIterator with iterators from the stack |
| il.append(new INVOKESPECIAL(initSI)); |
| |
| // This is a special case for the //* path with or without predicates |
| Expression stp = _step; |
| if (stp instanceof ParentLocationPath) |
| stp = ((ParentLocationPath)stp).getStep(); |
| |
| if ((_path instanceof Step) && (stp instanceof Step)) { |
| final int path = ((Step)_path).getAxis(); |
| final int step = ((Step)stp).getAxis(); |
| if ((path == Axis.DESCENDANTORSELF && step == Axis.CHILD) || |
| (path == Axis.PRECEDING && step == Axis.PARENT)) { |
| final int incl = cpg.addMethodref(NODE_ITERATOR_BASE, |
| "includeSelf", |
| "()" + NODE_ITERATOR_SIG); |
| il.append(new INVOKEVIRTUAL(incl)); |
| } |
| } |
| |
| /* |
| * If this pattern contains a sequence of descendant iterators we |
| * run the risk of returning the same node several times. We put |
| * a new iterator on top of the existing one to assure node order |
| * and prevent returning a single node multiple times. |
| */ |
| if (_orderNodes) { |
| final int order = cpg.addInterfaceMethodref(DOM_INTF, |
| ORDER_ITERATOR, |
| ORDER_ITERATOR_SIG); |
| il.append(methodGen.loadDOM()); |
| il.append(SWAP); |
| il.append(methodGen.loadContextNode()); |
| il.append(new INVOKEINTERFACE(order, 3)); |
| } |
| } |
| } |
