/*
* reserved comment block
* DO NOT REMOVE OR ALTER!
*/
/*
* Copyright 2001-2006 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: KeyCall.java,v 1.7 2006/06/19 19:49:04 spericas Exp $
*/
package com.sun.org.apache.xalan.internal.xsltc.compiler;
import java.util.Vector;
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.BranchHandle;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.GOTO;
import com.sun.org.apache.bcel.internal.generic.IFGT;
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.InstructionHandle;
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.bcel.internal.generic.PUSH;
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.StringType;
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;
/**
* @author Morten Jorgensen
* @author Santiago Pericas-Geertsen
*/
final class KeyCall extends FunctionCall {
/**
* The name of the key.
*/
private Expression _name;
/**
* The value to look up in the key/index.
*/
private Expression _value;
/**
* The value's data type.
*/
private Type _valueType; // The value's data type
/**
* Expanded qname when name is literal.
*/
private QName _resolvedQName = null;
/**
* Get the parameters passed to function:
* key(String name, String value)
* key(String name, NodeSet value)
* The 'arguments' vector should contain two parameters for key() calls,
* one holding the key name and one holding the value(s) to look up. The
* vector has only one parameter for id() calls (the key name is always
* "##id" for id() calls).
*
* @param fname The function name (should be 'key' or 'id')
* @param arguments A vector containing the arguments the the function
*/
public KeyCall(QName fname, Vector arguments) {
super(fname, arguments);
switch(argumentCount()) {
case 1:
_name = null;
_value = argument(0);
break;
case 2:
_name = argument(0);
_value = argument(1);
break;
default:
_name = _value = null;
break;
}
}
/**
* If this call to key() is in a top-level element like another variable
* or param, add a dependency between that top-level element and the
* referenced key. For example,
*
* <xsl:key name="x" .../>
* <xsl:variable name="y" select="key('x', 1)"/>
*
* and assuming this class represents "key('x', 1)", add a reference
* between variable y and key x. Note that if 'x' is unknown statically
* in key('x', 1), there's nothing we can do at this point.
*/
public void addParentDependency() {
// If name unknown statically, there's nothing we can do
if (_resolvedQName == null) return;
SyntaxTreeNode node = this;
while (node != null && node instanceof TopLevelElement == false) {
node = node.getParent();
}
TopLevelElement parent = (TopLevelElement) node;
if (parent != null) {
parent.addDependency(getSymbolTable().getKey(_resolvedQName));
}
}
/**
* Type check the parameters for the id() or key() function.
* The index name (for key() call only) must be a string or convertable
* to a string, and the lookup-value must be a string or a node-set.
* @param stable The parser's symbol table
* @throws TypeCheckError When the parameters have illegal type
*/
public Type typeCheck(SymbolTable stable) throws TypeCheckError {
final Type returnType = super.typeCheck(stable);
// Run type check on the key name (first argument) - must be a string,
// and if it is not it must be converted to one using string() rules.
if (_name != null) {
final Type nameType = _name.typeCheck(stable);
if (_name instanceof LiteralExpr) {
final LiteralExpr literal = (LiteralExpr) _name;
_resolvedQName =
getParser().getQNameIgnoreDefaultNs(literal.getValue());
}
else if (nameType instanceof StringType == false) {
_name = new CastExpr(_name, Type.String);
}
}
// Run type check on the value for this key. This value can be of
// any data type, so this should never cause any type-check errors.
// If the value is a reference, then we have to defer the decision
// of how to process it until run-time.
// If the value is known not to be a node-set, then it should be
// converted to a string before the lookup is done. If the value is
// known to be a node-set then this process (convert to string, then
// do lookup) should be applied to every node in the set, and the
// result from all lookups should be added to the resulting node-set.
_valueType = _value.typeCheck(stable);
if (_valueType != Type.NodeSet
&& _valueType != Type.Reference
&& _valueType != Type.String) {
_value = new CastExpr(_value, Type.String);
_valueType = _value.typeCheck(stable);
}
// If in a top-level element, create dependency to the referenced key
addParentDependency();
return returnType;
}
/**
* This method is called when the constructor is compiled in
* Stylesheet.compileConstructor() and not as the syntax tree is traversed.
* <p>This method will generate byte code that produces an iterator
* for the nodes in the node set for the key or id function call.
* @param classGen The Java class generator
* @param methodGen The method generator
*/
public void translate(ClassGenerator classGen,
MethodGenerator methodGen) {
final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
// Returns the KeyIndex object of a given name
final int getKeyIndex = cpg.addMethodref(TRANSLET_CLASS,
"getKeyIndex",
"(Ljava/lang/String;)"+
KEY_INDEX_SIG);
// KeyIndex.setDom(Dom, node) => void
final int keyDom = cpg.addMethodref(KEY_INDEX_CLASS,
"setDom",
"(" + DOM_INTF_SIG + "I)V");
// Initialises a KeyIndex to return nodes with specific values
final int getKeyIterator =
cpg.addMethodref(KEY_INDEX_CLASS,
"getKeyIndexIterator",
"(" + _valueType.toSignature() + "Z)"
+ KEY_INDEX_ITERATOR_SIG);
// Initialise the index specified in the first parameter of key()
il.append(classGen.loadTranslet());
if (_name == null) {
il.append(new PUSH(cpg,"##id"));
} else if (_resolvedQName != null) {
il.append(new PUSH(cpg, _resolvedQName.toString()));
} else {
_name.translate(classGen, methodGen);
}
// Generate following byte code:
//
// KeyIndex ki = translet.getKeyIndex(_name)
// ki.setDom(translet.dom);
// ki.getKeyIndexIterator(_value, true) - for key()
// OR
// ki.getKeyIndexIterator(_value, false) - for id()
il.append(new INVOKEVIRTUAL(getKeyIndex));
il.append(DUP);
il.append(methodGen.loadDOM());
il.append(methodGen.loadCurrentNode());
il.append(new INVOKEVIRTUAL(keyDom));
_value.translate(classGen, methodGen);
il.append((_name != null) ? ICONST_1: ICONST_0);
il.append(new INVOKEVIRTUAL(getKeyIterator));
}
}