1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef COMPONENTS_METRICS_METRICS_LOG_MANAGER_H_
6#define COMPONENTS_METRICS_METRICS_LOG_MANAGER_H_
7
8#include <string>
9#include <vector>
10
11#include "base/basictypes.h"
12#include "base/memory/scoped_ptr.h"
13#include "components/metrics/metrics_log.h"
14#include "components/metrics/persisted_logs.h"
15
16namespace metrics {
17
18// Manages all the log objects used by a MetricsService implementation. Keeps
19// track of both an in progress log and a log that is staged for uploading as
20// text, as well as saving logs to, and loading logs from, persistent storage.
21class MetricsLogManager {
22 public:
23  // The metrics log manager will persist it's unsent logs by storing them in
24  // |local_state|, and will not persist ongoing logs over
25  // |max_ongoing_log_size|.
26  MetricsLogManager(PrefService* local_state, size_t max_ongoing_log_size);
27  ~MetricsLogManager();
28
29  // Makes |log| the current_log. This should only be called if there is not a
30  // current log.
31  void BeginLoggingWithLog(scoped_ptr<MetricsLog> log);
32
33  // Returns the in-progress log.
34  MetricsLog* current_log() { return current_log_.get(); }
35
36  // Closes current_log(), compresses it, and stores the compressed log for
37  // later, leaving current_log() NULL.
38  void FinishCurrentLog();
39
40  // Returns true if there are any logs waiting to be uploaded.
41  bool has_unsent_logs() const {
42    return initial_log_queue_.size() || ongoing_log_queue_.size();
43  }
44
45  // Populates staged_log_text() with the next stored log to send.
46  // Should only be called if has_unsent_logs() is true.
47  void StageNextLogForUpload();
48
49  // Returns true if there is a log that needs to be, or is being, uploaded.
50  bool has_staged_log() const {
51    return initial_log_queue_.has_staged_log() ||
52        ongoing_log_queue_.has_staged_log();
53  }
54
55  // The text of the staged log, as a serialized protobuf.
56  // Will trigger a DCHECK if there is no staged log.
57  const std::string& staged_log() const {
58    return initial_log_queue_.has_staged_log() ?
59        initial_log_queue_.staged_log() : ongoing_log_queue_.staged_log();
60  }
61
62  // The SHA1 hash of the staged log.
63  // Will trigger a DCHECK if there is no staged log.
64  const std::string& staged_log_hash() const {
65    return initial_log_queue_.has_staged_log() ?
66        initial_log_queue_.staged_log_hash() :
67        ongoing_log_queue_.staged_log_hash();
68  }
69
70  // Discards the staged log.
71  void DiscardStagedLog();
72
73  // Closes and discards |current_log|.
74  void DiscardCurrentLog();
75
76  // Sets current_log to NULL, but saves the current log for future use with
77  // ResumePausedLog(). Only one log may be paused at a time.
78  // TODO(stuartmorgan): Pause/resume support is really a workaround for a
79  // design issue in initial log writing; that should be fixed, and pause/resume
80  // removed.
81  void PauseCurrentLog();
82
83  // Restores the previously paused log (if any) to current_log().
84  // This should only be called if there is not a current log.
85  void ResumePausedLog();
86
87  // Saves the staged log, then clears staged_log().
88  // If |store_type| is PROVISIONAL_STORE, it can be dropped from storage with
89  // a later call to DiscardLastProvisionalStore (if it hasn't already been
90  // staged again).
91  // This is intended to be used when logs are being saved while an upload is in
92  // progress, in case the upload later succeeds.
93  // This can only be called if has_staged_log() is true.
94  void StoreStagedLogAsUnsent(PersistedLogs::StoreType store_type);
95
96  // Discards the last log stored with StoreStagedLogAsUnsent with |store_type|
97  // set to PROVISIONAL_STORE, as long as it hasn't already been re-staged. If
98  // the log is no longer present, this is a no-op.
99  void DiscardLastProvisionalStore();
100
101  // Saves any unsent logs to persistent storage.
102  void PersistUnsentLogs();
103
104  // Loads any unsent logs from persistent storage.
105  void LoadPersistedUnsentLogs();
106
107 private:
108  // Saves |log_data| as the given type.
109  void StoreLog(const std::string& log_data, MetricsLog::LogType log_type);
110
111  // Tracks whether unsent logs (if any) have been loaded from the serializer.
112  bool unsent_logs_loaded_;
113
114  // The log that we are still appending to.
115  scoped_ptr<MetricsLog> current_log_;
116
117  // A paused, previously-current log.
118  scoped_ptr<MetricsLog> paused_log_;
119
120  // Logs that have not yet been sent.
121  PersistedLogs initial_log_queue_;
122  PersistedLogs ongoing_log_queue_;
123
124  DISALLOW_COPY_AND_ASSIGN(MetricsLogManager);
125};
126
127}  // namespace metrics
128
129#endif  // COMPONENTS_METRICS_METRICS_LOG_MANAGER_H_
130