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      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 
     16 namespace 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.
     21 class 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 any unsent logs to persistent storage.
     88   void PersistUnsentLogs();
     89 
     90   // Loads any unsent logs from persistent storage.
     91   void LoadPersistedUnsentLogs();
     92 
     93  private:
     94   // Saves |log_data| as the given type.
     95   void StoreLog(const std::string& log_data, MetricsLog::LogType log_type);
     96 
     97   // Tracks whether unsent logs (if any) have been loaded from the serializer.
     98   bool unsent_logs_loaded_;
     99 
    100   // The log that we are still appending to.
    101   scoped_ptr<MetricsLog> current_log_;
    102 
    103   // A paused, previously-current log.
    104   scoped_ptr<MetricsLog> paused_log_;
    105 
    106   // Logs that have not yet been sent.
    107   PersistedLogs initial_log_queue_;
    108   PersistedLogs ongoing_log_queue_;
    109 
    110   DISALLOW_COPY_AND_ASSIGN(MetricsLogManager);
    111 };
    112 
    113 }  // namespace metrics
    114 
    115 #endif  // COMPONENTS_METRICS_METRICS_LOG_MANAGER_H_
    116