plugins/org.eclipse.egf.pattern/src/org/eclipse/egf/pattern/utils/FileHelper.java

/**
 * <copyright>
 * 
 * Copyright (c) 2009-2010 Thales Corporate Services S.A.S.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 * Thales Corporate Services S.A.S - initial API and implementation
 * 
 * </copyright>
 */

package org.eclipse.egf.pattern.utils;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IFolder;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Platform;
import org.eclipse.egf.common.constant.EGFCommonConstants;
import org.eclipse.egf.core.fcore.IPlatformFcore;
import org.eclipse.egf.pattern.Messages;
import org.eclipse.emf.common.util.URI;
import org.osgi.framework.Bundle;

/**
 * 
 * @author Thomas Guiu
 * 
 */
public class FileHelper {

    public static void setContent(IFile file, String source) throws CoreException {
        setContent(file, source, true);
    }

    public static void setContent(IFile file, String source, boolean keepHistory) throws CoreException {
        setContent(file, new ByteArrayInputStream(source.getBytes()), keepHistory);
    }

    private static void setContent(IFile file, InputStream source, boolean keepHistory) throws CoreException {
        if (file.exists())
            file.setContents(source, true, keepHistory, null);
        else {
            createParentfolders(file.getProject(), file.getProjectRelativePath().removeLastSegments(1));
            file.create(source, true, null);
        }
    }

    private static void createParentfolders(IProject project, IPath folderPath) throws CoreException {
        if (folderPath.isEmpty())
            return;
        IFolder folder = project.getFolder(folderPath);
        if (folder == null)
            throw new IllegalStateException();
        if (!folder.exists()) {
            createParentfolders(project, folderPath.removeLastSegments(1));
            folder.create(true, true, null);
        }
    }

    /**
     * This method tries to read a file from the project and then from the
     * plugins.
     * 
     */
    public static String getContent(String pluginId, IProject project, IPath templatePath) throws CoreException, IOException {
        IFile file = project.getFile(templatePath);
        if (file == null)
            throw new IllegalStateException();
        if (file.exists())
            return getFileContent(file);

        Bundle bundle = Platform.getBundle(pluginId);
        if (bundle == null)
            throw new IllegalArgumentException(Messages.bind(Messages.fileHelper_error1, pluginId));

        URL entry = bundle.getEntry(templatePath.toPortableString());
        if (entry == null)
            throw new IllegalStateException(Messages.bind(Messages.fileHelper_error2, templatePath.toPortableString(), pluginId));

        return getContent(entry.openStream());
    }

    /**
     * Reads a file from a plugin who lives in the workspace or RT. If the file
     * doesn't exist an empty string is returned.
     * 
     */
    public static String getContent(IPlatformFcore component, URI uri) throws CoreException, IOException {
        if (component == null)
            throw new IllegalArgumentException(Messages.fileHelper_error3);
        IProject project = component.getPlatformBundle().getProject();
        if (project != null) {
            IFile file = project.getFile(uri.path());
            if (file == null)
                throw new IllegalStateException();
            if (!file.exists())
                return EGFCommonConstants.EMPTY_STRING;
            return getFileContent(file);
        }

        Bundle bundle = component.getPlatformBundle().getBundle();
        if (bundle == null)
            throw new IllegalArgumentException(Messages.bind(Messages.fileHelper_error1, component.getPlatformBundle().getBundleId()));
        URL entry = bundle.getEntry(uri.path());
        if (entry == null)
            throw new IllegalStateException(Messages.bind(Messages.fileHelper_error2, uri.toString(), component.getPlatformBundle().getBundleId()));

        return getContent(entry.openStream());

    }

    public static String getFileContent(IFile file) throws CoreException, IOException {
        return getContent(file.getContents());
    }

    private static String getContent(InputStream contents) throws CoreException, IOException {
        byte[] buf = null;
        try {
            buf = new byte[contents.available()];
            contents.read(buf);
        } finally {
            if (contents != null)
                contents.close();
        }
        return new String(buf);
    }

}