org.jacoco.agent.rt/src/org/jacoco/agent/rt/internal/output/FileOutput.java

/*******************************************************************************
 * Copyright (c) 2009, 2017 Mountainminds GmbH & Co. KG and Contributors
 * 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:
 *    Brock Janiczak - initial API and implementation
 *    
 *******************************************************************************/
package org.jacoco.agent.rt.internal.output;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;

import org.jacoco.core.data.ExecutionDataWriter;
import org.jacoco.core.runtime.AgentOptions;
import org.jacoco.core.runtime.RuntimeData;

/**
 * Local only agent output that will write coverage data to the filesystem. This
 * controller uses the following agent options:
 * <ul>
 * <li>destfile</li>
 * <li>append</li>
 * </ul>
 */
public class FileOutput implements IAgentOutput {

	private RuntimeData data;

	private File destFile;

	private boolean append;

	public final void startup(final AgentOptions options, final RuntimeData data)
			throws IOException {
		this.data = data;
		this.destFile = new File(options.getDestfile()).getAbsoluteFile();
		this.append = options.getAppend();
		final File folder = destFile.getParentFile();
		if (folder != null) {
			folder.mkdirs();
		}
		// Make sure we can write to the file:
		openFile().close();
	}

	public void writeExecutionData(final boolean reset) throws IOException {
		final OutputStream output = openFile();
		try {
			final ExecutionDataWriter writer = new ExecutionDataWriter(output);
			data.collect(writer, writer, reset);
		} finally {
			output.close();
		}
	}

	public void shutdown() throws IOException {
		// Nothing to do
	}

	private OutputStream openFile() throws IOException {
		final FileOutputStream file = new FileOutputStream(destFile, append);
		// Avoid concurrent writes from different agents running in parallel:
		file.getChannel().lock();
		return file;
	}

}