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// Copyright (c) 2009 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_
#include "base/basictypes.h"
#include "base/compiler_specific.h"
#include "base/task.h"
#include "testing/gtest/include/gtest/gtest_prod.h" // For FRIEND_TEST
class Profile;
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(ExternalMetricsTest, ParseExternalMetricsFile);
friend class base::RefCountedThreadSafe<ExternalMetrics>;
public:
ExternalMetrics() {}
// Begins the external data collection. Profile is passed through to
// UserMetrics::RecordAction. The lifetime of profile must exceed that of
// the external metrics object.
void Start(Profile* profile);
private:
// There is one function with this type for each action or histogram.
typedef void (*RecordFunctionType)(const char*);
// The type of event associated with each name.
typedef enum {
EVENT_TYPE_ACTION,
EVENT_TYPE_HISTOGRAM
} MetricsEventType;
// Used in mapping names (C strings) into event-recording functions.
typedef struct {
const char* name;
RecordFunctionType function;
MetricsEventType type;
} RecordFunctionTableEntry;
typedef void (*RecorderType)(const char*, const char*); // See SetRecorder.
// The max length of a message (name-value pair, plus header)
static const int kMetricsMessageMaxLength = 4096;
~ExternalMetrics();
// Protect action recorders from being called when external_metrics_profile is
// null. This could happen when testing, or in the unlikely case that the
// order of object deletion at shutdown changes.
static void RecordActionWrapper(RecordFunctionType);
// Maps a name to an entry in the record function table. Return NULL on
// failure.
static const ExternalMetrics::RecordFunctionTableEntry* FindRecordEntry(
const char* name);
// Initializes a table that maps a metric name to a function that logs that
// metric.
void InitializeFunctionTable();
// Passes an event, either an ACTION or HISTOGRAM depending on |name|, to the
// UMA service. For a histogram, |value| contains the numeric value, in a
// format that depends on |name|.
static void RecordEvent(const char* name, const char* value);
// 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();
// Sets the event logging function. Exists only because of testing.
void SetRecorder(RecorderType recorder) {
recorder_ = recorder;
}
// This table maps event names to event recording functions.
static RecordFunctionTableEntry function_table_[];
RecorderType recorder_; // See SetRecorder.
DISALLOW_COPY_AND_ASSIGN(ExternalMetrics);
};
} // namespace chromeos
#endif // CHROME_BROWSER_CHROMEOS_EXTERNAL_METRICS_H_
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