1 /*
2  * Copyright (C) 2019 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 
17 #pragma once
18 
19 #include <gtest/gtest_prod.h>
20 
21 #include <condition_variable>
22 #include <mutex>
23 #include <queue>
24 
25 #include "LogEvent.h"
26 
27 namespace android {
28 namespace os {
29 namespace statsd {
30 
31 /**
32  * A zero copy thread safe queue buffer for producing and consuming LogEvent.
33  */
34 class LogEventQueue {
35 public:
LogEventQueue(size_t maxSize)36     explicit LogEventQueue(size_t maxSize) : mQueueLimit(maxSize){};
37 
38     /**
39      * Blocking read one event from the queue.
40      */
41     std::unique_ptr<LogEvent> waitPop();
42 
43     struct Result {
44         bool success = false;
45         int64_t oldestTimestampNs = 0;
46         int32_t size = 0;
47     };
48 
49     /**
50      * Puts a LogEvent ptr to the end of the queue.
51      * Returns false on failure when the queue is full, and output the oldest event timestamp
52      * in the queue. Returns true on success and new queue size.
53      */
54     Result push(std::unique_ptr<LogEvent> event);
55 
56 private:
57     const size_t mQueueLimit;
58     std::condition_variable mCondition;
59     std::mutex mMutex;
60     std::queue<std::unique_ptr<LogEvent>> mQueue;
61 
62     friend class SocketParseMessageTest;
63 
64     FRIEND_TEST(SocketParseMessageTest, TestProcessMessage);
65     FRIEND_TEST(SocketParseMessageTest, TestProcessMessageEmptySetExplicitSet);
66     FRIEND_TEST(SocketParseMessageTest, TestProcessMessageFilterCompleteSet);
67     FRIEND_TEST(SocketParseMessageTest, TestProcessMessageFilterPartialSet);
68     FRIEND_TEST(SocketParseMessageTest, TestProcessMessageFilterToggle);
69 };
70 
71 }  // namespace statsd
72 }  // namespace os
73 }  // namespace android
74