/*
* Copyright 2010 the original author or authors.
*
* 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.
*/
package org.gradle.api.plugins.antlr.internal;
import java.lang.reflect.Method;
import java.util.Enumeration;
import java.util.ArrayList;
import java.util.List;
import antlr.collections.impl.IndexedVector;
import antlr.preprocessor.GrammarFile;
/**
* Antlr defines its {@link antlr.preprocessor.Grammar} class as package-protected for some unfortunate reason. So this
* class acts as a delegate to the Antlr {@link antlr.preprocessor.Grammar} class, hiding all the ugly necessary
* reflection code.
*
* @author Steve Ebersole
*/
public class GrammarDelegate {
public static List<GrammarDelegate> extractGrammarDelegates(GrammarFile antlrGrammarFile) {
List<GrammarDelegate> grammarDelegates = new ArrayList<GrammarDelegate>();
Enumeration grammarFileGramars = antlrGrammarFile.getGrammars().elements();
while (grammarFileGramars.hasMoreElements()) {
grammarDelegates.add(new GrammarDelegate(grammarFileGramars.nextElement()));
}
return grammarDelegates;
}
private final String className;
private final String importVocab;
private final String exportVocab;
private final GrammarDelegate superGrammarDelegate;
public GrammarDelegate(Object antlrGrammarMetadata) {
try {
final Method getNameMethod = ANTLR_GRAMMAR_CLASS.getDeclaredMethod("getName", NO_ARG_SIGNATURE);
getNameMethod.setAccessible(true);
this.className = (String) getNameMethod.invoke(antlrGrammarMetadata, NO_ARGS);
final Method getSuperGrammarMethod = ANTLR_GRAMMAR_CLASS.getMethod("getSuperGrammar", NO_ARG_SIGNATURE);
getSuperGrammarMethod.setAccessible(true);
final Object antlrSuperGrammarGrammarMetadata = getSuperGrammarMethod.invoke(antlrGrammarMetadata, NO_ARGS);
this.superGrammarDelegate = antlrSuperGrammarGrammarMetadata == null ? null : new GrammarDelegate(
antlrSuperGrammarGrammarMetadata);
Method getOptionsMethod = ANTLR_GRAMMAR_CLASS.getMethod("getOptions", NO_ARG_SIGNATURE);
getOptionsMethod.setAccessible(true);
IndexedVector options = (IndexedVector) getOptionsMethod.invoke(antlrGrammarMetadata, NO_ARGS);
Method getRHSMethod = ANTLR_OPTION_CLASS.getMethod("getRHS", NO_ARG_SIGNATURE);
getRHSMethod.setAccessible(true);
final Object importVocabOption = options == null ? null : options.getElement("importVocab");
this.importVocab = importVocabOption == null ? null : vocabName((String) getRHSMethod.invoke(
importVocabOption, NO_ARGS));
final Object exportVocabOption = options == null ? null : options.getElement("exportVocab");
this.exportVocab = exportVocabOption == null ? null : vocabName((String) getRHSMethod.invoke(
exportVocabOption, NO_ARGS));
} catch (Throwable t) {
throw new IllegalStateException("Error accessing Antlr grammar metadata", t);
}
}
/**
* Retrieves the unqualified name of the lexer/parser class.
*
* @return The unqualified lexer/parser class name.
*/
public String getClassName() {
return className;
}
/**
* Retrieves the name of this vocabulary imported by this grammar.
*
* @return The gammar's imported vocabulary name.
*/
public String getImportVocab() {
return importVocab;
}
/**
* Retrieves the name of this vocabulary exported by this grammar.
*
* @return The gammar's exported vocabulary name.
*/
public String getExportVocab() {
return exportVocab;
}
/**
* Retrieves the grammar delegate associated with this grammars super grammar deduced during preprocessing from its
* extends clause.
*
* @return The super-grammar grammar delegate
*/
public GrammarDelegate getSuperGrammarDelegate() {
return superGrammarDelegate;
}
private GrammarMetadata associatedGrammarMetadata;
public void associateWith(GrammarMetadata associatedGrammarMetadata) {
this.associatedGrammarMetadata = associatedGrammarMetadata;
}
public GrammarMetadata getAssociatedGrammarMetadata() {
return associatedGrammarMetadata;
}
private String vocabName(String vocabName) {
if (vocabName == null) {
return null;
}
vocabName = vocabName.trim();
if (vocabName.endsWith(";")) {
vocabName = vocabName.substring(0, vocabName.length() - 1);
}
return vocabName;
}
private static final Class ANTLR_GRAMMAR_CLASS;
private static final Class ANTLR_OPTION_CLASS;
static {
ANTLR_GRAMMAR_CLASS = loadAntlrClass("antlr.preprocessor.Grammar");
ANTLR_OPTION_CLASS = loadAntlrClass("antlr.preprocessor.Option");
}
public static final Class[] NO_ARG_SIGNATURE = new Class[0];
public static final Object[] NO_ARGS = new Object[0];
private static Class loadAntlrClass(String className) {
try {
return Class.forName(className, true, GrammarDelegate.class.getClassLoader());
} catch (ClassNotFoundException e) {
throw new IllegalStateException("Unable to locate Antlr class [" + className + "]", e );
}
}
}