1/*
2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23package org.graalvm.compiler.debug;
24
25/**
26 * A helper class for {@link AbstractKey}s that can nest and need to split out accumulated and flat
27 * values for some kind of counter-like measurement.
28 */
29public abstract class CloseableCounter implements DebugCloseable {
30
31    protected final DebugContext debug;
32    protected final CloseableCounter parent;
33    protected final AccumulatedKey counter;
34    protected final long start;
35    protected long nestedAmountToSubtract;
36
37    CloseableCounter(DebugContext debug, CloseableCounter parent, AccumulatedKey counter) {
38        this.debug = debug;
39        this.parent = parent;
40        this.start = getCounterValue();
41        this.counter = counter;
42    }
43
44    @Override
45    public DebugContext getDebug() {
46        return debug;
47    }
48
49    /**
50     * A hook for subclasses. Lets them perform custom operations with the value since the last
51     * invocation of {@link CloseableCounter#close()} of this accumulated
52     * {@link CloseableCounter#counter}.
53     *
54     * @param difference since the last invocation of this counter flat
55     */
56    protected void interceptDifferenceAccm(long difference) {
57        // hook for subclasses
58    }
59
60    /**
61     * A hook for subclasses. Lets them perform custom operations with the value since the last
62     * invocation of {@link CloseableCounter#close()} of this flat {@link CloseableCounter#counter}.
63     *
64     * @param difference since the last invocation of this counter flat
65     */
66    protected void interceptDifferenceFlat(long difference) {
67        // hook for subclasses
68    }
69
70    @Override
71    public void close() {
72        long end = getCounterValue();
73        long difference = end - start;
74        if (parent != null) {
75            if (!counter.getName().equals(parent.counter.getName())) {
76                parent.nestedAmountToSubtract += difference;
77                // Look for our counter in an outer scope and fix up
78                // the adjustment to the flat count
79                CloseableCounter ancestor = parent.parent;
80                while (ancestor != null) {
81                    if (ancestor.counter.getName().equals(counter.getName())) {
82                        ancestor.nestedAmountToSubtract -= difference;
83                        break;
84                    }
85                    ancestor = ancestor.parent;
86                }
87            }
88        }
89        long flatAmount = difference - nestedAmountToSubtract;
90        counter.addToCurrentValue(debug, difference);
91        counter.flat.addToCurrentValue(debug, flatAmount);
92        interceptDifferenceAccm(difference);
93        interceptDifferenceFlat(flatAmount);
94    }
95
96    abstract long getCounterValue();
97}
98