- /*
- * 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: Variable.java,v 1.27 2004/02/24 02:58:42 zongaro Exp $
- */
-
- package com.sun.org.apache.xalan.internal.xsltc.compiler;
-
- import com.sun.org.apache.bcel.internal.classfile.Field;
- import com.sun.org.apache.bcel.internal.generic.ACONST_NULL;
- import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
- import com.sun.org.apache.bcel.internal.generic.DCONST;
- import com.sun.org.apache.bcel.internal.generic.ICONST;
- import com.sun.org.apache.bcel.internal.generic.InstructionList;
- import com.sun.org.apache.bcel.internal.generic.PUTFIELD;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.BooleanType;
- 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.IntType;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeType;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.RealType;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
- import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
-
- /**
- * @author Jacek Ambroziak
- * @author Santiago Pericas-Geertsen
- * @author Morten Jorgensen
- * @author Erwin Bolwidt <ejb@klomp.org>
- * @author John Howard <JohnH@schemasoft.com>
- */
- final class Variable extends VariableBase {
-
- public int getIndex() {
- return (_local != null) ? _local.getIndex() : -1;
- }
-
- /**
- * Parse the contents of the variable
- */
- public void parseContents(Parser parser) {
- // Parse 'name' and 'select' attributes plus parameter contents
- super.parseContents(parser);
-
- // Add a ref to this var to its enclosing construct
- SyntaxTreeNode parent = getParent();
- if (parent instanceof Stylesheet) {
- // Mark this as a global variable
- _isLocal = false;
- // Check if a global variable with this name already exists...
- Variable var = parser.getSymbolTable().lookupVariable(_name);
- // ...and if it does we need to check import precedence
- if (var != null) {
- final int us = this.getImportPrecedence();
- final int them = var.getImportPrecedence();
- // It is an error if the two have the same import precedence
- if (us == them) {
- final String name = _name.toString();
- reportError(this, parser, ErrorMsg.VARIABLE_REDEF_ERR,name);
- }
- // Ignore this if previous definition has higher precedence
- else if (them > us) {
- _ignore = true;
- return;
- }
- else {
- var.disable();
- }
- // Add this variable if we have higher precedence
- }
- ((Stylesheet)parent).addVariable(this);
- parser.getSymbolTable().addVariable(this);
- }
- else {
- _isLocal = true;
- }
- }
-
- /**
- * Runs a type check on either the variable element body or the
- * expression in the 'select' attribute
- */
- public Type typeCheck(SymbolTable stable) throws TypeCheckError {
-
- // Type check the 'select' expression if present
- if (_select != null) {
- _type = _select.typeCheck(stable);
- }
- // Type check the element contents otherwise
- else if (hasContents()) {
- typeCheckContents(stable);
- _type = Type.ResultTree;
- }
- else {
- _type = Type.Reference;
- }
- // The return type is void as the variable element does not leave
- // anything on the JVM's stack. The '_type' global will be returned
- // by the references to this variable, and not by the variable itself.
- return Type.Void;
- }
-
- /**
- * This method is part of a little trick that is needed to use local
- * variables inside nested for-each loops. See the initializeVariables()
- * method in the ForEach class for an explanation
- */
- public void initialize(ClassGenerator classGen, MethodGenerator methodGen) {
- final ConstantPoolGen cpg = classGen.getConstantPool();
- final InstructionList il = methodGen.getInstructionList();
-
- // This is only done for local variables that are actually used
- if (isLocal() && !_refs.isEmpty()) {
- // Create a variable slot if none is allocated
- if (_local == null) {
- _local = methodGen.addLocalVariable2(getEscapedName(),
- _type.toJCType(),
- il.getEnd());
- }
- // Push the default value on the JVM's stack
- if ((_type instanceof IntType) ||
- (_type instanceof NodeType) ||
- (_type instanceof BooleanType))
- il.append(new ICONST(0)); // 0 for node-id, integer and boolean
- else if (_type instanceof RealType)
- il.append(new DCONST(0)); // 0.0 for floating point numbers
- else
- il.append(new ACONST_NULL()); // and 'null' for anything else
- il.append(_type.STORE(_local.getIndex()));
- }
- }
-
- public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
- final ConstantPoolGen cpg = classGen.getConstantPool();
- final InstructionList il = methodGen.getInstructionList();
-
- final String name = getEscapedName();
-
- // Make sure that a variable instance is only compiled once
- if (_ignore) return;
- _ignore = true;
-
- if (isLocal()) {
- // Compile variable value computation
- translateValue(classGen, methodGen);
-
- // Add a new local variable and store value
- if (_refs.isEmpty()) { // Remove it if nobody uses the value
- il.append(_type.POP());
- _local = null;
- }
- else { // Store in local var slot if referenced
- if (_local == null) mapRegister(methodGen);
- il.append(_type.STORE(_local.getIndex()));
- }
- }
- else {
- String signature = _type.toSignature();
-
- // Global variables are store in class fields
- if (classGen.containsField(name) == null) {
- classGen.addField(new Field(ACC_PUBLIC,
- cpg.addUtf8(name),
- cpg.addUtf8(signature),
- null, cpg.getConstantPool()));
-
- // Push a reference to "this" for putfield
- il.append(classGen.loadTranslet());
- // Compile variable value computation
- translateValue(classGen, methodGen);
- // Store the variable in the allocated field
- il.append(new PUTFIELD(cpg.addFieldref(classGen.getClassName(),
- name, signature)));
- }
- }
- }
- }