1/*******************************************************************************
2 * Copyright (c) 2009, 2018 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.internal.instr;
13
14import org.jacoco.core.internal.data.CRC64;
15import org.jacoco.core.internal.flow.ClassProbesAdapter;
16import org.jacoco.core.runtime.IExecutionDataAccessorGenerator;
17import org.objectweb.asm.ClassReader;
18import org.objectweb.asm.Opcodes;
19
20/**
21 * Factory to find a suitable strategy to access the probe array for a given
22 * class.
23 */
24public final class ProbeArrayStrategyFactory {
25
26	private ProbeArrayStrategyFactory() {
27	}
28
29	/**
30	 * Creates a suitable strategy instance for the class described by the given
31	 * reader. Created instance must be used only to process a class or
32	 * interface for which it has been created and must be used only once.
33	 *
34	 * @param reader
35	 *            reader to get information about the class
36	 * @param accessorGenerator
37	 *            accessor to the coverage runtime
38	 * @return strategy instance
39	 */
40	public static IProbeArrayStrategy createFor(final ClassReader reader,
41			final IExecutionDataAccessorGenerator accessorGenerator) {
42
43		final String className = reader.getClassName();
44		final int version = getVersion(reader);
45		final long classId = CRC64.classId(reader.b);
46		final boolean withFrames = version >= Opcodes.V1_6;
47
48		if (isInterfaceOrModule(reader)) {
49			final ProbeCounter counter = getProbeCounter(reader);
50			if (counter.getCount() == 0) {
51				return new NoneProbeArrayStrategy();
52			}
53			if (version >= Opcodes.V1_8 && counter.hasMethods()) {
54				return new InterfaceFieldProbeArrayStrategy(className, classId,
55						counter.getCount(), accessorGenerator);
56			} else {
57				return new LocalProbeArrayStrategy(className, classId,
58						counter.getCount(), accessorGenerator);
59			}
60		} else {
61			return new ClassFieldProbeArrayStrategy(className, classId,
62					withFrames, accessorGenerator);
63		}
64	}
65
66	private static boolean isInterfaceOrModule(final ClassReader reader) {
67		return (reader.getAccess()
68				& (Opcodes.ACC_INTERFACE | Opcodes.ACC_MODULE)) != 0;
69	}
70
71	private static int getVersion(final ClassReader reader) {
72		return reader.readShort(6);
73	}
74
75	private static ProbeCounter getProbeCounter(final ClassReader reader) {
76		final ProbeCounter counter = new ProbeCounter();
77		reader.accept(new ClassProbesAdapter(counter, false), 0);
78		return counter;
79	}
80
81}
82