text: // Copyright (c) 2010 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 CHROME_BROWSER_CHROMEOS_EXTERNAL_METRICS_H_
  #define CHROME_BROWSER_CHROMEOS_EXTERNAL_METRICS_H_
  #pragma once
  
  #include "base/basictypes.h"
  #include "base/compiler_specific.h"
  #include "base/file_path.h"
  #include "base/gtest_prod_util.h"
  #include "base/hash_tables.h"
  #include "base/task.h"
  
  namespace chromeos {
  
  // ExternalMetrics is a service that Chrome offers to Chrome OS to upload
  // metrics to the UMA server on its behalf.  Chrome periodically reads the
  // content of a well-know file, and parses it into name-value pairs, each
  // representing a Chrome OS metrics event. The events are logged using the
  // normal UMA mechanism. The file is then truncated to zero size. Chrome uses
  // flock() to synchronize accesses to the file.
  class ExternalMetrics : public base::RefCountedThreadSafe<ExternalMetrics> {
    FRIEND_TEST_ALL_PREFIXES(ExternalMetricsTest, ParseExternalMetricsFile);
    friend class base::RefCountedThreadSafe<ExternalMetrics>;
  
   public:
    ExternalMetrics();
  
    // Begins the external data collection.  This service is started and stopped
    // by the chrome metrics service.  Calls to RecordAction originate in the
    // File thread but are executed in the UI thread.
    void Start();
  
   private:
    // There is one function with this type for each action.
    typedef void (*RecordFunctionType)();
  
    typedef void (*RecorderType)(const char*, const char*);  // For testing only.
  
    // The max length of a message (name-value pair, plus header)
    static const int kMetricsMessageMaxLength = 1024;  // be generous
  
    ~ExternalMetrics() {}
  
    // Passes an action event to the UMA service on the UI thread.
    void RecordActionUI(std::string action_string);
  
    // Passes an action event to the UMA service.
    void RecordAction(const char* action_name);
  
    // Records an external crash of the given string description to
    // UMA service on the UI thread.
    void RecordCrashUI(const std::string& crash_kind);
  
    // Records an external crash of the given string description.
    void RecordCrash(const std::string& crash_kind);
  
    // Passes an histogram event to the UMA service.  |histogram_data| is in the
    // form <histogram-name> <sample> <min> <max> <buckets_count>.
    void RecordHistogram(const char* histogram_data);
  
    // Passes a linear histogram event to the UMA service.  |histogram_data| is
    // in the form <histogram-name> <sample> <max>.
    void RecordLinearHistogram(const char* histogram_data);
  
    // Collects external events from metrics log file.  This is run at periodic
    // intervals.
    void CollectEvents();
  
    // Calls CollectEvents and reschedules a future collection.
    void CollectEventsAndReschedule();
  
    // Schedules a metrics event collection in the future.
    void ScheduleCollector();
  
    // Maps histogram or action names to recorder structs.
    base::hash_map<std::string, RecordFunctionType> action_recorders_;
  
    // Set containing known user actions.
    base::hash_set<std::string> valid_user_actions_;
  
    // Used for testing only.
    RecorderType test_recorder_;
    FilePath test_path_;
    DISALLOW_COPY_AND_ASSIGN(ExternalMetrics);
  };
  
  }  // namespace chromeos
  
  #endif  // CHROME_BROWSER_CHROMEOS_EXTERNAL_METRICS_H_
  