/*
 * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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.
 */

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.INVOKESTATIC;
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.PUSH;
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.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.utils.XML11Char;

Author:
Jacek Ambroziak, Santiago Pericas-Geertsen, Morten Jorgensen/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author Morten Jorgensen
 */
final class XslElement extends Instruction {

    private String  _prefix;
    private boolean _ignore = false;
    private boolean _isLiteralName = true;
    private AttributeValueTemplate _name;
    private AttributeValueTemplate _namespace;

    
Displays the contents of the element
/**
     * Displays the contents of the element
     */
    public void display(int indent) {
        indent(indent);
        Util.println("Element " + _name);
        displayContents(indent + IndentIncrement);
    }

    public void parseContents(Parser parser) {
        final SymbolTable stable = parser.getSymbolTable();

        // Handle the 'name' attribute
        String name = getAttribute("name");
        if (name == EMPTYSTRING) {
            ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_ELEM_NAME_ERR,
                                        name, this);
            parser.reportError(WARNING, msg);
            parseChildren(parser);
            _ignore = true;     // Ignore the element if the QName is invalid
            return;
        }

        // Get namespace attribute
        String namespace = getAttribute("namespace");

        // Optimize compilation when name is known at compile time
        _isLiteralName = Util.isLiteral(name);
        if (_isLiteralName) {
            if (!XML11Char.isXML11ValidQName(name)) {
                ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_ELEM_NAME_ERR,
                                            name, this);
                parser.reportError(WARNING, msg);
                parseChildren(parser);
                _ignore = true;         // Ignore the element if the QName is invalid
                return;
            }

            final QName qname = parser.getQNameSafe(name);
            String prefix = qname.getPrefix();
            String local = qname.getLocalPart();

            if (prefix == null) {
                prefix = EMPTYSTRING;
            }

            if (!hasAttribute("namespace")) {
                namespace = lookupNamespace(prefix);
                if (namespace == null) {
                    ErrorMsg err = new ErrorMsg(ErrorMsg.NAMESPACE_UNDEF_ERR,
                                                prefix, this);
                    parser.reportError(WARNING, err);
                    parseChildren(parser);
                    _ignore = true;     // Ignore the element if prefix is undeclared
                    return;
                }
                _prefix = prefix;
                _namespace = new AttributeValueTemplate(namespace, parser, this);
            }
            else {
                if (prefix == EMPTYSTRING) {
                    if (Util.isLiteral(namespace)) {
                        prefix = lookupPrefix(namespace);
                        if (prefix == null) {
                            prefix = stable.generateNamespacePrefix();
                        }
                    }

                    // Prepend prefix to local name
                    final StringBuffer newName = new StringBuffer(prefix);
                    if (prefix != EMPTYSTRING) {
                        newName.append(':');
                    }
                    name = newName.append(local).toString();
                }
                _prefix = prefix;
                _namespace = new AttributeValueTemplate(namespace, parser, this);
            }
        }
        else {
            _namespace = (namespace == EMPTYSTRING) ? null :
                         new AttributeValueTemplate(namespace, parser, this);
        }

        _name = new AttributeValueTemplate(name, parser, this);

        final String useSets = getAttribute("use-attribute-sets");
        if (useSets.length() > 0) {
            if (!Util.isValidQNames(useSets)) {
                ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, useSets, this);
                parser.reportError(Constants.ERROR, err);
            }
            setFirstElement(new UseAttributeSets(useSets, parser));
        }

        parseChildren(parser);
    }

    
Run type check on element name & contents
/**
     * Run type check on element name & contents
     */
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
        if (!_ignore) {
            _name.typeCheck(stable);
            if (_namespace != null) {
                _namespace.typeCheck(stable);
            }
        }
        typeCheckContents(stable);
        return Type.Void;
    }

    
This method is called when the name of the element is known at compile time.
In this case, there is no need to inspect the element name at runtime to
determine if a prefix exists, needs to be generated, etc.
/**
     * This method is called when the name of the element is known at compile time.
     * In this case, there is no need to inspect the element name at runtime to
     * determine if a prefix exists, needs to be generated, etc.
     */
    public void translateLiteral(ClassGenerator classGen, MethodGenerator methodGen) {
        final ConstantPoolGen cpg = classGen.getConstantPool();
        final InstructionList il = methodGen.getInstructionList();

        if (!_ignore) {
            il.append(methodGen.loadHandler());
            _name.translate(classGen, methodGen);
            il.append(DUP2);
            il.append(methodGen.startElement());

            if (_namespace != null) {
                il.append(methodGen.loadHandler());
                il.append(new PUSH(cpg, _prefix));
                _namespace.translate(classGen,methodGen);
                il.append(methodGen.namespace());
            }
        }

        translateContents(classGen, methodGen);

        if (!_ignore) {
            il.append(methodGen.endElement());
        }
    }

    
At runtime the compilation of xsl:element results in code that: (i)
evaluates the avt for the name, (ii) checks for a prefix in the name
(iii) generates a new prefix and create a new qname when necessary
(iv) calls startElement() on the handler (v) looks up a uri in the XML
when the prefix is not known at compile time (vi) calls namespace()
on the handler (vii) evaluates the contents (viii) calls endElement().
/**
     * At runtime the compilation of xsl:element results in code that: (i)
     * evaluates the avt for the name, (ii) checks for a prefix in the name
     * (iii) generates a new prefix and create a new qname when necessary
     * (iv) calls startElement() on the handler (v) looks up a uri in the XML
     * when the prefix is not known at compile time (vi) calls namespace()
     * on the handler (vii) evaluates the contents (viii) calls endElement().
     */
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
        final ConstantPoolGen cpg = classGen.getConstantPool();
        final InstructionList il = methodGen.getInstructionList();

        // Optimize translation if element name is a literal
        if (_isLiteralName) {
            translateLiteral(classGen, methodGen);
            return;
        }

        if (!_ignore) {

            // if the qname is an AVT, then the qname has to be checked at runtime if it is a valid qname
            LocalVariableGen nameValue =
                    methodGen.addLocalVariable2("nameValue",
                                                Util.getJCRefType(STRING_SIG),
                                                null);

            // store the name into a variable first so _name.translate only needs to be called once
            _name.translate(classGen, methodGen);
            nameValue.setStart(il.append(new ASTORE(nameValue.getIndex())));
            il.append(new ALOAD(nameValue.getIndex()));

            // call checkQName if the name is an AVT
            final int check = cpg.addMethodref(BASIS_LIBRARY_CLASS, "checkQName",
                            "("
                            +STRING_SIG
                            +")V");
            il.append(new INVOKESTATIC(check));

            // Push handler for call to endElement()
            il.append(methodGen.loadHandler());

            // load name value again
            nameValue.setEnd(il.append(new ALOAD(nameValue.getIndex())));

            if (_namespace != null) {
                _namespace.translate(classGen, methodGen);
            }
            else {
                il.append(ACONST_NULL);
            }

            // Push additional arguments
            il.append(methodGen.loadHandler());
            il.append(methodGen.loadDOM());
            il.append(methodGen.loadCurrentNode());

            // Invoke BasisLibrary.startXslElemCheckQName()
            il.append(new INVOKESTATIC(
            cpg.addMethodref(BASIS_LIBRARY_CLASS, "startXslElement",
                    "(" + STRING_SIG
                    + STRING_SIG
                    + TRANSLET_OUTPUT_SIG
                    + DOM_INTF_SIG + "I)" + STRING_SIG)));


        }

        translateContents(classGen, methodGen);

        if (!_ignore) {
            il.append(methodGen.endElement());
        }
    }

    
Override this method to make sure that xsl:attributes are not
copied to output if this xsl:element is to be ignored
/**
     * Override this method to make sure that xsl:attributes are not
     * copied to output if this xsl:element is to be ignored
     */
    public void translateContents(ClassGenerator classGen,
                                  MethodGenerator methodGen) {
        final int n = elementCount();
        for (int i = 0; i < n; i++) {
            final SyntaxTreeNode item = getContents().get(i);
            if (_ignore && item instanceof XslAttribute) continue;
            item.translate(classGen, methodGen);
        }
    }

}