code: /*
   * 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.
   */
  /*
   * $Id$
   */
  
  package org.apache.xalan.xsltc.compiler.util;
  
  import org.apache.bcel.generic.ALOAD;
  import org.apache.bcel.generic.ASTORE;
  import org.apache.bcel.generic.CHECKCAST;
  import org.apache.bcel.generic.ConstantPoolGen;
  import org.apache.bcel.generic.GETFIELD;
  import org.apache.bcel.generic.IFEQ;
  import org.apache.bcel.generic.INVOKEINTERFACE;
  import org.apache.bcel.generic.INVOKESPECIAL;
  import org.apache.bcel.generic.INVOKEVIRTUAL;
  import org.apache.bcel.generic.Instruction;
  import org.apache.bcel.generic.InstructionList;
  import org.apache.bcel.generic.LocalVariableGen;
  import org.apache.bcel.generic.NEW;
  import org.apache.bcel.generic.PUSH;
  import org.apache.xalan.xsltc.compiler.Constants;
  import org.apache.xalan.xsltc.compiler.FlowList;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   * @author Morten Jorgensen
   */
  public final class ResultTreeType extends Type {
      private final String _methodName;
  
      protected ResultTreeType() {
  	_methodName = null;
      }
  
      public ResultTreeType(String methodName) {
  	_methodName = methodName;
      }
  
      public String toString() {
  	return "result-tree";
      }
  
      public boolean identicalTo(Type other) {
  	return (other instanceof ResultTreeType);
      }
  
      public String toSignature() {
  	return DOM_INTF_SIG;
      }
  
      public org.apache.bcel.generic.Type toJCType() {
  	return Util.getJCRefType(toSignature());
      }
  
      public String getMethodName() {
  	return _methodName;
      }
  
      public boolean implementedAsMethod() {
  	return _methodName != null;
      }
  
      /**
       * Translates a result tree to object of internal type <code>type</code>. 
       * The translation to int is undefined since result trees
       * are always converted to reals in arithmetic expressions.
       *
       * @param classGen A BCEL class generator
       * @param methodGen A BCEL method generator
       * @param type An instance of the type to translate the result tree to
       * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
       */
      public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
  			    Type type) {
  	if (type == Type.String) {
  	    translateTo(classGen, methodGen, (StringType)type);
  	}
  	else if (type == Type.Boolean) {
  	    translateTo(classGen, methodGen, (BooleanType)type);
  	}
  	else if (type == Type.Real) {
  	    translateTo(classGen, methodGen, (RealType)type);
  	}
  	else if (type == Type.NodeSet) {
  	    translateTo(classGen, methodGen, (NodeSetType)type);
  	}
  	else if (type == Type.Reference) {
  	    translateTo(classGen, methodGen, (ReferenceType)type);
  	}
  	else if (type == Type.Object) {
  	    translateTo(classGen, methodGen, (ObjectType) type);
  	}
  	else {
  	    ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
  					toString(), type.toString());
  	    classGen.getParser().reportError(Constants.FATAL, err);
  	}
      }
  
      /**
       * Expects an result tree on the stack and pushes a boolean.
       * Translates a result tree to a boolean by first converting it to string.
       *
       * @param classGen A BCEL class generator
       * @param methodGen A BCEL method generator
       * @param type An instance of BooleanType (any)
       * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
       */
      public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
  			    BooleanType type) {
  	// A result tree is always 'true' when converted to a boolean value,
  	// since the tree always has at least one node (the root).
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  	il.append(POP);      // don't need the DOM reference
  	il.append(ICONST_1); // push 'true' on the stack
      }
  
      /**
       * Expects an result tree on the stack and pushes a string.
       *
       * @param classGen A BCEL class generator
       * @param methodGen A BCEL method generator
       * @param type An instance of StringType (any)
       * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
       */
      public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
  			    StringType type) {
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  	
  	if (_methodName == null) {
  	    int index = cpg.addInterfaceMethodref(DOM_INTF,
  						  "getStringValue", 
  						  "()"+STRING_SIG);
  	    il.append(new INVOKEINTERFACE(index, 1));
  	}
  	else {
  	    final String className = classGen.getClassName();
  	    final int current = methodGen.getLocalIndex("current");
  	    
  	    // Push required parameters 
  	    il.append(classGen.loadTranslet());
  	    if (classGen.isExternal()) {
  		il.append(new CHECKCAST(cpg.addClass(className)));
  	    }
  	    il.append(DUP);
  	    il.append(new GETFIELD(cpg.addFieldref(className, "_dom",
  						   DOM_INTF_SIG)));
  
  	    // Create a new instance of a StringValueHandler
  	    int index = cpg.addMethodref(STRING_VALUE_HANDLER, "<init>", "()V");
  	    il.append(new NEW(cpg.addClass(STRING_VALUE_HANDLER)));
  	    il.append(DUP);
  	    il.append(DUP);
  	    il.append(new INVOKESPECIAL(index));
  	    
  	    // Store new Handler into a local variable
  	    final LocalVariableGen handler =
  		methodGen.addLocalVariable("rt_to_string_handler", 
  					   Util.getJCRefType(STRING_VALUE_HANDLER_SIG),
  					   null, null);
  	    handler.setStart(il.append(new ASTORE(handler.getIndex())));
  
  	    // Call the method that implements this result tree
  	    index = cpg.addMethodref(className, _methodName,
  				     "("+DOM_INTF_SIG+TRANSLET_OUTPUT_SIG+")V");
  	    il.append(new INVOKEVIRTUAL(index));
  	    
  	    // Restore new handler and call getValue()
  	    handler.setEnd(il.append(new ALOAD(handler.getIndex())));
  	    index = cpg.addMethodref(STRING_VALUE_HANDLER,
  				     "getValue",
  				     "()" + STRING_SIG);
  	    il.append(new INVOKEVIRTUAL(index));
  	}
      }
  
      /**
       * Expects an result tree on the stack and pushes a real.
       * Translates a result tree into a real by first converting it to string.
       *
       * @param classGen A BCEL class generator
       * @param methodGen A BCEL method generator
       * @param type An instance of RealType (any)
       * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
       */
      public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
  			    RealType type) {
  	translateTo(classGen, methodGen, Type.String);
  	Type.String.translateTo(classGen, methodGen, Type.Real);	
      }
  
      /**
       * Expects a result tree on the stack and pushes a boxed result tree.
       * Result trees are already boxed so the translation is just a NOP.
       *
       * @param classGen A BCEL class generator
       * @param methodGen A BCEL method generator
       * @param type An instance of ReferenceType (any)
       * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
       */
      public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
  			    ReferenceType type) {
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  
  	if (_methodName == null) {
  	    il.append(NOP);
  	}
  	else {
  	    LocalVariableGen domBuilder, newDom;
  	    final String className = classGen.getClassName();
  	    final int current = methodGen.getLocalIndex("current");
  
  	    // Push required parameters 
  	    il.append(classGen.loadTranslet());
  	    if (classGen.isExternal()) {
  		il.append(new CHECKCAST(cpg.addClass(className)));
  	    }
  	    il.append(methodGen.loadDOM());
  
  	    // Create new instance of DOM class (with RTF_INITIAL_SIZE nodes)
  	    il.append(methodGen.loadDOM());
  	    int index = cpg.addInterfaceMethodref(DOM_INTF,
  				 "getResultTreeFrag",
  				 "(IZ)" + DOM_INTF_SIG);
  	    il.append(new PUSH(cpg, RTF_INITIAL_SIZE));
  	    il.append(new PUSH(cpg, false));
  	    il.append(new INVOKEINTERFACE(index,3));
  	    il.append(DUP);
  	    
  	    // Store new DOM into a local variable
  	    newDom = methodGen.addLocalVariable("rt_to_reference_dom", 
  						Util.getJCRefType(DOM_INTF_SIG),
  						null, null);
  	    il.append(new CHECKCAST(cpg.addClass(DOM_INTF_SIG)));
  	    newDom.setStart(il.append(new ASTORE(newDom.getIndex())));
  
  	    // Overwrite old handler with DOM handler
  	    index = cpg.addInterfaceMethodref(DOM_INTF,
  				 "getOutputDomBuilder",
  				 "()" + TRANSLET_OUTPUT_SIG);
  
  	    il.append(new INVOKEINTERFACE(index,1));
  	    //index = cpg.addMethodref(DOM_IMPL,
  		//		     "getOutputDomBuilder", 
  		//		     "()" + TRANSLET_OUTPUT_SIG);
  	    //il.append(new INVOKEVIRTUAL(index));
  	    il.append(DUP);
  	    il.append(DUP);
  
  	    // Store DOM handler in a local in order to call endDocument()
  	    domBuilder =
  		methodGen.addLocalVariable("rt_to_reference_handler", 
  					   Util.getJCRefType(TRANSLET_OUTPUT_SIG),
  					   null, null);
  	    domBuilder.setStart(il.append(new ASTORE(domBuilder.getIndex())));
  
  	    // Call startDocument on the new handler
  	    index = cpg.addInterfaceMethodref(TRANSLET_OUTPUT_INTERFACE, 
  					      "startDocument", "()V");
  	    il.append(new INVOKEINTERFACE(index, 1));
  
  	    // Call the method that implements this result tree
  	    index = cpg.addMethodref(className,
  				     _methodName,
  				     "("
  				     + DOM_INTF_SIG
  				     + TRANSLET_OUTPUT_SIG
  				     +")V");
  	    il.append(new INVOKEVIRTUAL(index));
  
  	    // Call endDocument on the DOM handler
  	    domBuilder.setEnd(il.append(new ALOAD(domBuilder.getIndex())));
  	    index = cpg.addInterfaceMethodref(TRANSLET_OUTPUT_INTERFACE, 
  					      "endDocument", "()V");
  	    il.append(new INVOKEINTERFACE(index, 1));
  
  	    // Push the new DOM on the stack
  	    newDom.setEnd(il.append(new ALOAD(newDom.getIndex())));
  	}
      }
  
      /**
       * Expects a result tree on the stack and pushes a node-set (iterator).
       * Note that the produced iterator is an iterator for the DOM that
       * contains the result tree, and not the DOM that is currently in use.
       * This conversion here will therefore not directly work with elements
       * such as <xsl:apply-templates> and <xsl:for-each> without the DOM
       * parameter/variable being updates as well.
       *
       * @param classGen A BCEL class generator
       * @param methodGen A BCEL method generator
       * @param type An instance of NodeSetType (any)
       * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
       */
      public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
  			    NodeSetType type) {
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  
  	// Put an extra copy of the result tree (DOM) on the stack
  	il.append(DUP);
  
  	// DOM adapters containing a result tree are not initialised with
  	// translet-type to DOM-type mapping. This must be done now for
  	// XPath expressions and patterns to work for the iterator we create.
  	il.append(classGen.loadTranslet()); // get names array
  	il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
  					       NAMES_INDEX,
  					       NAMES_INDEX_SIG)));
  	il.append(classGen.loadTranslet()); // get uris array
  	il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
  					       URIS_INDEX,
  					       URIS_INDEX_SIG)));
  	il.append(classGen.loadTranslet()); // get types array
  	il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
  					       TYPES_INDEX,
  					       TYPES_INDEX_SIG)));
  	il.append(classGen.loadTranslet()); // get namespaces array
  	il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
  					       NAMESPACE_INDEX,
  					       NAMESPACE_INDEX_SIG)));
  	// Pass the type mappings to the DOM adapter
  	final int mapping = cpg.addInterfaceMethodref(DOM_INTF,
  						      "setupMapping",
  						      "(["+STRING_SIG+
  						      "["+STRING_SIG+
  						      "[I" +
  						      "["+STRING_SIG+")V");
  	il.append(new INVOKEINTERFACE(mapping, 5));
  	il.append(DUP);
  
  	// Create an iterator for the root node of the DOM adapter
  	final int iter = cpg.addInterfaceMethodref(DOM_INTF,
  						   "getIterator",
  						   "()"+NODE_ITERATOR_SIG);
  	il.append(new INVOKEINTERFACE(iter, 1));	
      }
  
      /**
       * Subsume result tree into ObjectType.
       *
       * @see	org.apache.xalan.xsltc.compiler.util.Type#translateTo
       */
      public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
  			    ObjectType type) {
  	methodGen.getInstructionList().append(NOP);	
      }
  
      /**
       * Translates a result tree into a non-synthesized boolean.
       * It does not push a 0 or a 1 but instead returns branchhandle list
       * to be appended to the false list.
       *
       * @param classGen A BCEL class generator
       * @param methodGen A BCEL method generator
       * @param type An instance of BooleanType (any)
       * @see org.apache.xalan.xsltc.compiler.util.Type#translateToDesynthesized
       */
      public FlowList translateToDesynthesized(ClassGenerator classGen, 
  					     MethodGenerator methodGen, 
  					     BooleanType type) {
  	final InstructionList il = methodGen.getInstructionList();
  	translateTo(classGen, methodGen, Type.Boolean);
  	return new FlowList(il.append(new IFEQ(null)));
      }
  
      /**
       * Translates a result tree to a Java type denoted by <code>clazz</code>. 
       * Expects a result tree on the stack and pushes an object
       * of the appropriate type after coercion. Result trees are translated
       * to W3C Node or W3C NodeList and the translation is done
       * via node-set type.
       *
       * @param classGen A BCEL class generator
       * @param methodGen A BCEL method generator
       * @param clazz An reference to the Class to translate to
       * @see org.apache.xalan.xsltc.compiler.util.Type#translateTo
       */
      public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
  			    Class clazz) {
  	final String className = clazz.getName();
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  
  	if (className.equals("org.w3c.dom.Node")) {
  	    translateTo(classGen, methodGen, Type.NodeSet);
  	    int index = cpg.addInterfaceMethodref(DOM_INTF,
  						  MAKE_NODE,
  						  MAKE_NODE_SIG2);
  	    il.append(new INVOKEINTERFACE(index, 2));
  	}
  	else if (className.equals("org.w3c.dom.NodeList")) {
  	    translateTo(classGen, methodGen, Type.NodeSet);
  	    int index = cpg.addInterfaceMethodref(DOM_INTF,
  						  MAKE_NODE_LIST,
  						  MAKE_NODE_LIST_SIG2);
  	    il.append(new INVOKEINTERFACE(index, 2));
  	}
  	else if (className.equals("java.lang.Object")) {
  	    il.append(NOP);
  	}
          else if (className.equals("java.lang.String")) {
              translateTo(classGen, methodGen, Type.String);
          }
  	else {
  	    ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,
  					toString(), className);
  	    classGen.getParser().reportError(Constants.FATAL, err);
  	}
      }
  
      /**
       * Translates an object of this type to its boxed representation.
       */ 
      public void translateBox(ClassGenerator classGen,
  			     MethodGenerator methodGen) {
  	translateTo(classGen, methodGen, Type.Reference);
      }
  
      /**
       * Translates an object of this type to its unboxed representation.
       */ 
      public void translateUnBox(ClassGenerator classGen,
  			       MethodGenerator methodGen) {
  	methodGen.getInstructionList().append(NOP);
      }
  
      /**
       * Returns the class name of an internal type's external representation.
       */
      public String getClassName() {
  	return(DOM_INTF);
      }
  
      public Instruction LOAD(int slot) {
  	return new ALOAD(slot);
      }
  	
      public Instruction STORE(int slot) {
  	return new ASTORE(slot);
      }
  }
  