components/metrics/drive_metrics_provider.h

   1 // Copyright 2015 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_DRIVE_METRICS_PROVIDER_H_
   6 #define COMPONENTS_METRICS_DRIVE_METRICS_PROVIDER_H_
   7
   8 #include "base/callback_forward.h"
   9 #include "base/gtest_prod_util.h"
  10 #include "base/macros.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/weak_ptr.h"
  13 #include "base/sequenced_task_runner.h"
  14 #include "base/threading/thread_checker.h"
  15 #include "components/metrics/metrics_provider.h"
  16 #include "components/metrics/proto/system_profile.pb.h"
  17
  18 namespace base {
  19 class FilePath;
  20 }
  21
  22 namespace metrics {
  23
  24 // Provides metrics about the local drives on a user's computer. Currently only
  25 // checks to see if they incur a seek-time penalty (e.g. if they're SSDs).
  26 //
  27 // Defers gathering metrics until after "rush hour" (startup) so as to not bog
  28 // down the file thread.
  29 class DriveMetricsProvider : public metrics::MetricsProvider {
  30  public:
  31   DriveMetricsProvider(scoped_refptr<base::SequencedTaskRunner> file_thread,
  32                        int local_state_path_key);
  33   ~DriveMetricsProvider() override;
  34
  35   // metrics::MetricsDataProvider:
  36   void ProvideSystemProfileMetrics(
  37       metrics::SystemProfileProto* system_profile_proto) override;
  38
  39   // Called to start gathering metrics.
  40   void GetDriveMetrics(const base::Closure& done_callback);
  41
  42  private:
  43   FRIEND_TEST_ALL_PREFIXES(DriveMetricsProviderTest, HasSeekPenalty);
  44
  45   // A response to querying a drive as to whether it incurs a seek penalty.
  46   // |has_seek_penalty| is set if |success| is true.
  47   struct SeekPenaltyResponse {
  48     SeekPenaltyResponse();
  49     bool success;
  50     bool has_seek_penalty;
  51   };
  52
  53   struct DriveMetrics {
  54     SeekPenaltyResponse app_drive;
  55     SeekPenaltyResponse user_data_drive;
  56   };
  57
  58   // Determine whether the device that services |path| has a seek penalty.
  59   // Returns false if it couldn't be determined (e.g., |path| doesn't exist).
  60   static bool HasSeekPenalty(const base::FilePath& path,
  61                              bool* has_seek_penalty);
  62
  63   // Gather metrics about various drives on |file_thread_|.
  64   static DriveMetrics GetDriveMetricsOnFileThread(int local_state_path_key);
  65
  66   // Tries to determine whether there is a penalty for seeking on the drive that
  67   // hosts |path_service_key| (for example: the drive that holds "Local State").
  68   static void QuerySeekPenalty(int path_service_key,
  69                                SeekPenaltyResponse* response);
  70
  71   // Called when metrics are done being gathered from the FILE thread.
  72   // |done_callback| is the callback that should be called once all metrics are
  73   // gathered.
  74   void GotDriveMetrics(const base::Closure& done_callback,
  75                        const DriveMetrics& metrics);
  76
  77   // Fills |drive| with information from successful |response|s.
  78   void FillDriveMetrics(const SeekPenaltyResponse& response,
  79                         metrics::SystemProfileProto::Hardware::Drive* drive);
  80
  81   // The thread on which file operations are performed (supplied by the
  82   // embedder).
  83   scoped_refptr<base::SequencedTaskRunner> file_thread_;
  84
  85   // The key to give to base::PathService to obtain the path to local state
  86   // (supplied by the embedder).
  87   int local_state_path_key_;
  88
  89   // Information gathered about various important drives.
  90   DriveMetrics metrics_;
  91
  92   base::ThreadChecker thread_checker_;
  93   base::WeakPtrFactory<DriveMetricsProvider> weak_ptr_factory_;
  94
  95   DISALLOW_COPY_AND_ASSIGN(DriveMetricsProvider);
  96 };
  97
  98 }  // namespace metrics
  99
 100 #endif  // COMPONENTS_METRICS_DRIVE_METRICS_PROVIDER_H_