Copyright (c) 2004, 2013 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
    Philippe Ombredanne (pombredanne@nexb.com) - bug 125367
/*******************************************************************************
 * Copyright (c) 2004, 2013 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Philippe Ombredanne (pombredanne@nexb.com) - bug 125367
 *******************************************************************************/
package org.eclipse.ant.internal.core.contentDescriber;

import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;

import javax.xml.parsers.ParserConfigurationException;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.IExecutableExtension;
import org.eclipse.core.runtime.content.IContentDescription;
import org.eclipse.core.runtime.content.XMLContentDescriber;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

A content describer for Ant buildfiles.

If project top level element is found then if: target sub-elements are found returns VALID default attribute is found returns VALID some other
likely Ant element is found (classpath, import, macrodef, path, property, taskdef, typedef) returns VALID else: returns INDETERMINATE else returns
INDETERMINATE

Since:
3.1/**
 * A content describer for Ant buildfiles.
 * <p>
 * If project top level element is found then if: target sub-elements are found returns VALID default attribute is found returns VALID some other
 * likely Ant element is found (classpath, import, macrodef, path, property, taskdef, typedef) returns VALID else: returns INDETERMINATE else returns
 * INDETERMINATE
 * </p>
 * 
 * @since 3.1
 */
public final class AntBuildfileContentDescriber extends XMLContentDescriber implements IExecutableExtension {

	/*
	 * (Intentionally not included in javadoc) Determines the validation status for the given contents.
	 * 
	 * @param contents the contents to be evaluated
	 * 
	 * @return one of the following:<ul> <li><code>VALID</code></li>, <li><code>INVALID</code></li>, <li><code>INDETERMINATE</code></li> </ul>
	 * 
	 * @throws IOException
	 */
	private int checkCriteria(InputSource contents) throws IOException {
		AntHandler antHandler = new AntHandler();
		try {
			if (!antHandler.parseContents(contents)) {
				return INDETERMINATE;
			}
		}
		catch (SAXException e) {
			// we may be handed any kind of contents... it is normal we fail to parse
			return INDETERMINATE;
		}
		catch (ParserConfigurationException e) {
			// some bad thing happened - force this describer to be disabled
			String message = "Internal Error: XML parser configuration error during content description for Ant buildfiles"; //$NON-NLS-1$
			throw new RuntimeException(message, e);
		}
		// Check to see if we matched our criteria.
		if (antHandler.hasRootProjectElement()) {
			if (antHandler.hasProjectDefaultAttribute() || antHandler.hasTargetElement() || antHandler.hasAntElement()) {
				// project and default attribute or project and target element(s)
				// or project and top level ant element(s) (classpath, import, macrodef, path, property, taskdef, typedef)
				return VALID;
			}
			// only a top level project element...maybe an Ant buildfile
			return INDETERMINATE;
		}

		return INDETERMINATE;
	}

	/*
	 * (Intentionally not included in javadoc)
	 * 
	 * @see IContentDescriber#describe(InputStream, IContentDescription)
	 */
	@Override
	public int describe(InputStream contents, IContentDescription description) throws IOException {
		// call the basic XML describer to do basic recognition
		if (super.describe(contents, description) == INVALID) {
			return INVALID;
		}
		// super.describe will have consumed some chars, need to rewind
		contents.reset();
		// Check to see if we matched our criteria.
		return checkCriteria(new InputSource(contents));
	}

	/*
	 * (Intentionally not included in javadoc)
	 * 
	 * @see IContentDescriber#describe(Reader, IContentDescription)
	 */
	@Override
	public int describe(Reader contents, IContentDescription description) throws IOException {
		// call the basic XML describer to do basic recognition
		if (super.describe(contents, description) == INVALID) {
			return INVALID;
		}
		// super.describe will have consumed some chars, need to rewind
		contents.reset();
		// Check to see if we matched our criteria.
		return checkCriteria(new InputSource(contents));
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.core.runtime.IExecutableExtension#setInitializationData(org.eclipse.core.runtime.IConfigurationElement, java.lang.String,
	 * java.lang.Object)
	 */
	@Override
	public void setInitializationData(IConfigurationElement config, String propertyName, Object data) throws CoreException {
		// do nothing
	}
}