Index: components/metrics/file_metrics_provider.h |
diff --git a/components/metrics/file_metrics_provider.h b/components/metrics/file_metrics_provider.h |
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+// Copyright 2016 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#ifndef COMPONENTS_METRICS_FILE_METRICS_PROVIDER_H_ |
+#define COMPONENTS_METRICS_FILE_METRICS_PROVIDER_H_ |
+ |
+#include <list> |
+#include <string> |
+ |
+#include "base/callback.h" |
+#include "base/files/file_path.h" |
+#include "base/gtest_prod_util.h" |
+#include "base/memory/scoped_ptr.h" |
+#include "base/memory/weak_ptr.h" |
+#include "base/threading/thread_checker.h" |
+#include "base/time/time.h" |
+#include "components/metrics/metrics_provider.h" |
+ |
+class PrefRegistrySimple; |
+class PrefService; |
+ |
+namespace base { |
+class MemoryMappedFile; |
+class PersistentMemoryAllocator; |
+class TaskRunner; |
+} |
+ |
+namespace metrics { |
+ |
+// FileMetricsProvider gathers and logs histograms written to files on disk. |
+// Any number of files can be registered and will be polled once per upload |
+// cycle (at startup and periodically thereafter -- about every 30 minutes |
+// for desktop) for data to send. |
+class FileMetricsProvider : public metrics::MetricsProvider { |
+ public: |
+ enum FileType { |
+ // "Atomic" files are a collection of histograms that are written |
+ // completely in a single atomic operation (typically a write followed |
+ // by an atomic rename) and the file is never updated again except to |
+ // be replaced by a completely new set of histograms. This is the only |
+ // option that can be used if the file is not writeable by *this* |
+ // process. |
+ FILE_HISTOGRAMS_ATOMIC, |
+ |
+ // "Active" files may be open by one or more other processes and updated |
+ // at any time with new samples or new histograms. Such files may also be |
+ // inactive for any period of time only to be opened again and have new |
+ // data written to them. The file should probably never be deleted because |
+ // there would be no guarantee that the data has been reported. |
+ // TODO(bcwhite): Enable when read/write mem-mapped files are supported. |
+ //FILE_HISTOGRAMS_ACTIVE, |
+ }; |
+ |
+ FileMetricsProvider(const scoped_refptr<base::TaskRunner>& task_runner, |
+ PrefService* local_state); |
+ ~FileMetricsProvider() override; |
+ |
+ // Indicates a file to be monitored and how the file is used. Because some |
+ // metadata may persist across process restarts, preferences entries are |
+ // used based on the |prefs_key| name. Call RegisterPrefs() with the same |
+ // name to create the necessary keys in advance. Set |prefs_key| empty |
+ // if no persistence is required. |
+ void RegisterFile(const base::FilePath& path, |
+ FileType type, |
+ const base::StringPiece prefs_key); |
+ |
+ // Registers all necessary preferences for maintaining persistent state |
+ // about a monitored file across process restarts. The |prefs_key| is |
+ // typically the filename. |
+ static void RegisterPrefs(PrefRegistrySimple* prefs, |
+ const base::StringPiece prefs_key); |
+ |
+ private: |
+ friend class FileMetricsProviderTest; |
+ FRIEND_TEST_ALL_PREFIXES(FileMetricsProviderTest, AccessMetrics); |
+ |
+ // The different results that can occur accessing a file. |
+ enum AccessResult { |
+ // File was successfully mapped. |
+ ACCESS_RESULT_SUCCESS, |
+ |
+ // File does not exist. |
+ ACCESS_RESULT_DOESNT_EXIST, |
+ |
+ // File exists but not modified since last read. |
+ ACCESS_RESULT_NOT_MODIFIED, |
+ |
+ // File is not valid: is a directory or zero-size. |
+ ACCESS_RESULT_INVALID_FILE, |
+ |
+ // System could not map file into memory. |
+ ACCESS_RESULT_SYSTEM_MAP_FAILURE, |
+ |
+ // File had invalid contents. |
+ ACCESS_RESULT_INVALID_CONTENTS, |
+ |
+ ACCESS_RESULT_MAX |
+ }; |
+ |
+ // Information about files being monitored; defined and used exclusively |
+ // inside the .cc file. |
+ struct FileInfo; |
+ using FileInfoList = std::list<scoped_ptr<FileInfo>>; |
+ |
+ // Checks a list of files (on a task-runner allowed to do I/O) to see if |
+ // any should be processed during the next histogram collection. |
+ static void CheckAndMapNewMetricFilesOnTaskRunner(FileInfoList* files); |
+ |
+ // Checks an individual file as part of CheckAndMapNewMetricFilesOnTaskRunner. |
+ static AccessResult CheckAndMapNewMetrics(FileInfo* file); |
+ |
+ // Creates a task to check all monitored files for updates. |
+ void ScheduleFilesCheck(); |
+ |
+ // Creates a PersistentMemoryAllocator for a file that has been marked to |
+ // have its metrics collected. |
+ void CreateAllocatorForFile(FileInfo* file); |
+ |
+ // Records all histograms from a given file via a snapshot-manager. |
+ void RecordHistogramSnapshotsFromFile( |
+ base::HistogramSnapshotManager* snapshot_manager, |
+ FileInfo* file); |
+ |
+ // Takes a list of files checked by an external task and determines what |
+ // to do with each. |
+ void RecordFilesChecked(FileInfoList* checked); |
+ |
+ // Updates the persistent state information to show a file as being read. |
+ void RecordFileAsSeen(FileInfo* file); |
+ |
+ // metrics::MetricsDataProvider: |
+ void OnDidCreateMetricsLog() override; |
+ void RecordHistogramSnapshots( |
+ base::HistogramSnapshotManager* snapshot_manager) override; |
+ |
+ // A task-runner capable of performing I/O. |
+ scoped_refptr<base::TaskRunner> task_runner_; |
+ |
+ // A list of files not currently active that need to be checked for changes. |
+ FileInfoList files_to_check_; |
+ |
+ // A list of files that have data to be read and reported. |
+ FileInfoList files_to_read_; |
+ |
+ // The preferences-service used to store persistent state about files. |
+ PrefService* pref_service_; |
+ |
+ base::ThreadChecker thread_checker_; |
+ base::WeakPtrFactory<FileMetricsProvider> weak_factory_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(FileMetricsProvider); |
+}; |
+ |
+} // namespace metrics |
+ |
+#endif // COMPONENTS_METRICS_FILE_METRICS_PROVIDER_H_ |