1 /*
2  * Copyright (C) 2017 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 <android/os/IStatsCompanionService.h>
20 #include <utils/RefBase.h>
21 #include <mutex>
22 #include <vector>
23 #include "packages/UidMap.h"
24 
25 #include "guardrail/StatsdStats.h"
26 #include "logd/LogEvent.h"
27 #include "puller_util.h"
28 
29 namespace android {
30 namespace os {
31 namespace statsd {
32 
33 class StatsPuller : public virtual RefBase {
34 public:
35     explicit StatsPuller(const int tagId);
36 
~StatsPuller()37     virtual ~StatsPuller() {}
38 
39     // Pulls the most recent data.
40     // The data may be served from cache if consecutive pulls come within
41     // predefined cooldown time.
42     // Returns true if the pull was successful.
43     // Returns false when
44     //   1) the pull fails
45     //   2) pull takes longer than mPullTimeoutNs (intrinsic to puller)
46     // If a metric wants to make any change to the data, like timestamps, it
47     // should make a copy as this data may be shared with multiple metrics.
48     bool Pull(std::vector<std::shared_ptr<LogEvent>>* data);
49 
50     // Clear cache immediately
51     int ForceClearCache();
52 
53     // Clear cache if elapsed time is more than cooldown time
54     int ClearCacheIfNecessary(int64_t timestampNs);
55 
56     static void SetUidMap(const sp<UidMap>& uidMap);
57 
SetStatsCompanionService(sp<IStatsCompanionService> statsCompanionService)58     virtual void SetStatsCompanionService(sp<IStatsCompanionService> statsCompanionService){};
59 
60 protected:
61     const int mTagId;
62 
63 private:
64     mutable std::mutex mLock;
65 
66     // Real puller impl.
67     virtual bool PullInternal(std::vector<std::shared_ptr<LogEvent>>* data) = 0;
68 
69     bool mHasGoodData = false;
70 
71     int64_t mLastPullTimeNs;
72 
73     // Cache of data from last pull. If next request comes before cool down finishes,
74     // cached data will be returned.
75     // Cached data is cleared when
76     //   1) A pull fails
77     //   2) A new pull request comes after cooldown time.
78     //   3) clearCache is called.
79     std::vector<std::shared_ptr<LogEvent>> mCachedData;
80 
81     int clearCache();
82 
83     int clearCacheLocked();
84 
85     static sp<UidMap> mUidMap;
86 };
87 
88 }  // namespace statsd
89 }  // namespace os
90 }  // namespace android
91