bundles/org.eclipse.core.resources.semantic/src/org/eclipse/core/internal/resources/semantic/cacheservice/CachingOutputStream.java

/*******************************************************************************
 * Copyright (c) 2009 SAP AG.
 * 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:
 *    Eduard Bartsch (SAP AG) - initial API and implementation
 *    Mathias Kinzler (SAP AG) - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.internal.resources.semantic.cacheservice;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.MessageFormat;

import org.eclipse.core.resources.semantic.spi.ICacheUpdateCallback;
import org.eclipse.core.resources.semantic.spi.Util;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IPath;

class CachingOutputStream extends OutputStream {

	private final CacheService cacheService;
	private final ITemporaryContentHandle fileHandle;
	private final ICacheUpdateCallback callback;
	private final boolean appendMode;
	private boolean closed;

	protected CachingOutputStream(CacheService service, ITemporaryContentHandle tempHandle, boolean append, ICacheUpdateCallback callback) {

		this.cacheService = service;
		this.fileHandle = tempHandle;
		this.appendMode = append;
		this.callback = callback;
		this.closed = false;
	}

	@Override
	@SuppressWarnings("boxing")
	public void close() throws IOException {
		if (closed) {
			return;
		}

		try {
			InputStream stream = null;
			long timestamp = System.currentTimeMillis();

			closed = true;
			boolean shouldupdate;

			try {
				stream = this.fileHandle.closeAndGetContents();

				long appendPosition = this.fileHandle.getAppendPosition();
				skipUntilAppendPosition(stream, appendPosition);

				shouldupdate = this.callback.beforeCacheUpdate(stream, timestamp, this.appendMode);
			} finally {
				Util.safeClose(stream);
				stream = null;
			}

			if (shouldupdate) {
				this.cacheService.addFromTempHandle(this.fileHandle);

				IPath path = this.fileHandle.getKey();
				try {
					stream = this.cacheService.getContent(path);
					long appendPosition = this.fileHandle.getAppendPosition();

					skipUntilAppendPosition(stream, appendPosition);

					this.callback.cacheUpdated(stream, timestamp, this.appendMode);
				} finally {
					Util.safeClose(stream);
				}
			} else {
				this.fileHandle.rollback();
			}
		} catch (CoreException e) {
			this.fileHandle.rollback();
			throw new IOException(e.getMessage());
		}
	}

	private void skipUntilAppendPosition(InputStream stream, long appendPosition) throws IOException {
		long skipped = 0l;

		if (appendPosition > 0) {
			skipped = stream.skip(appendPosition);
		}

		if (skipped < appendPosition) {
			throw new IOException(MessageFormat.format(Messages.CachingOutputStream_CouldNotSkip_XMSG, appendPosition, skipped));
		}
	}

	@Override
	public void flush() throws IOException {
		this.fileHandle.flush();
	}

	@Override
	public void write(byte[] b, int off, int len) throws IOException {
		this.fileHandle.write(b, off, len);
	}

	@Override
	public void write(byte[] b) throws IOException {
		this.fileHandle.write(b);
	}

	@Override
	public void write(int b) throws IOException {
		this.fileHandle.write(b);
	}
}