HdmiLogger.java revision 2220f6f8a60a9aaf9be1fc3e5ce53ce410efb08e 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.server.hdmi;
18
19import android.os.SystemClock;
20import android.util.Pair;
21import android.util.Slog;
22
23import java.util.HashMap;
24
25/**
26 * A logger that prevents spammy log. For the same log message, it logs once every 20seconds.
27 * This class is not thread-safe.
28 */
29final class HdmiLogger {
30    // Logging duration for same error message.
31    private static final long ERROR_LOG_DURATTION_MILLIS = 20 * 1000;  // 20s
32
33    // Key (String): log message.
34    // Value (Pair(Long, Integer)): a pair of last log time millis and the number of logMessage.
35    // Cache for warning.
36    private final HashMap<String, Pair<Long, Integer>> mWarningTimingCache = new HashMap<>();
37    // Cache for error.
38    private final HashMap<String, Pair<Long, Integer>> mErrorTimingCache = new HashMap<>();
39
40    private final String mTag;
41
42    HdmiLogger(String tag) {
43        mTag = tag;
44    }
45
46    void warning(String logMessage) {
47        long curTime = SystemClock.uptimeMillis();
48        Pair<Long, Integer> timing = mWarningTimingCache.get(logMessage);
49        if (shouldLogNow(timing, curTime)) {
50            Slog.w(mTag, buildMessage(logMessage, timing, curTime));
51            mWarningTimingCache.put(logMessage, new Pair<>(curTime, 1));
52        } else {
53            increaseLogCount(mWarningTimingCache, logMessage);
54        }
55    }
56
57    void error(String logMessage) {
58        long curTime = SystemClock.uptimeMillis();
59        Pair<Long, Integer> timing = mErrorTimingCache.get(logMessage);
60        if (shouldLogNow(timing, curTime)) {
61            Slog.e(mTag, buildMessage(logMessage, timing, curTime));
62            mErrorTimingCache.put(logMessage, new Pair<>(curTime, 1));
63        } else {
64            increaseLogCount(mErrorTimingCache, logMessage);
65        }
66    }
67
68    private String buildMessage(String message, Pair<Long, Integer> timing, long curTime) {
69        return new StringBuilder()
70            .append("[").append(timing == null ? curTime : timing.second).append("]:")
71            .append(message).toString();
72    }
73
74    private void increaseLogCount(HashMap<String, Pair<Long, Integer>> cache, String message) {
75        Pair<Long, Integer> timing = cache.get(message);
76        if (timing != null) {
77            cache.put(message, new Pair<>(timing.first, timing.second + 1));
78        }
79    }
80
81    private boolean shouldLogNow(Pair<Long, Integer> timing, long curTime) {
82        return timing == null || curTime - timing.first > ERROR_LOG_DURATTION_MILLIS;
83    }
84}
85