1/*******************************************************************************
2 * Copyright (c) 2009, 2015 Mountainminds GmbH & Co. KG and Contributors
3 * All rights reserved. This program and the accompanying materials
4 * are made available under the terms of the Eclipse Public License v1.0
5 * which accompanies this distribution, and is available at
6 * http://www.eclipse.org/legal/epl-v10.html
7 *
8 * Contributors:
9 *    Marc R. Hoffmann - initial API and implementation
10 *
11 *******************************************************************************/
12package org.jacoco.core.data;
13
14import java.io.ByteArrayOutputStream;
15import java.io.IOException;
16import java.io.OutputStream;
17
18import org.jacoco.core.internal.data.CompactDataOutput;
19
20/**
21 * Serialization of execution data into binary streams.
22 */
23public class ExecutionDataWriter implements ISessionInfoVisitor,
24		IExecutionDataVisitor {
25
26	/** File format version, will be incremented for each incompatible change. */
27	public static final char FORMAT_VERSION = 0x1007;
28
29	/** Magic number in header for file format identification. */
30	public static final char MAGIC_NUMBER = 0xC0C0;
31
32	/** Block identifier for file headers. */
33	public static final byte BLOCK_HEADER = 0x01;
34
35	/** Block identifier for session information. */
36	public static final byte BLOCK_SESSIONINFO = 0x10;
37
38	/** Block identifier for execution data of a single class. */
39	public static final byte BLOCK_EXECUTIONDATA = 0x11;
40
41	/** Underlying data output */
42	protected final CompactDataOutput out;
43
44	/**
45	 * Creates a new writer based on the given output stream. Depending on the
46	 * nature of the underlying stream output should be buffered as most data is
47	 * written in single bytes.
48	 *
49	 * @param output
50	 *            binary stream to write execution data to
51	 * @throws IOException
52	 *             if the header can't be written
53	 */
54	public ExecutionDataWriter(final OutputStream output) throws IOException {
55		this.out = new CompactDataOutput(output);
56		writeHeader();
57	}
58
59	/**
60	 * Writes an file header to identify the stream and its protocol version.
61	 *
62	 * @throws IOException
63	 *             if the header can't be written
64	 */
65	private void writeHeader() throws IOException {
66		out.writeByte(BLOCK_HEADER);
67		out.writeChar(MAGIC_NUMBER);
68		out.writeChar(FORMAT_VERSION);
69	}
70
71	/**
72	 * Flushes the underlying stream.
73	 *
74	 * @throws IOException
75	 *             if the underlying stream can't be flushed
76	 */
77	public void flush() throws IOException {
78		out.flush();
79	}
80
81	public void visitSessionInfo(final SessionInfo info) {
82		try {
83			out.writeByte(BLOCK_SESSIONINFO);
84			out.writeUTF(info.getId());
85			out.writeLong(info.getStartTimeStamp());
86			out.writeLong(info.getDumpTimeStamp());
87		} catch (final IOException e) {
88			throw new RuntimeException(e);
89		}
90	}
91
92	public void visitClassExecution(final ExecutionData data) {
93		try {
94			out.writeByte(BLOCK_EXECUTIONDATA);
95			out.writeLong(data.getId());
96			out.writeUTF(data.getName());
97			out.writeBooleanArray(data.getProbes());
98		} catch (final IOException e) {
99			throw new RuntimeException(e);
100		}
101	}
102
103	/**
104	 * Returns the first bytes of a file that represents a valid execution data
105	 * file. In any case every execution data file starts with the three bytes
106	 * <code>0x01 0xC0 0xC0</code>.
107	 *
108	 * @return first bytes of a execution data file
109	 */
110	public static final byte[] getFileHeader() {
111		final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
112		try {
113			new ExecutionDataWriter(buffer);
114		} catch (final IOException e) {
115			// Must not happen with ByteArrayOutputStream
116			throw new AssertionError(e);
117		}
118		return buffer.toByteArray();
119	}
120
121}
122