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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_DRIVE_EVENT_LOGGER_H_
#define COMPONENTS_DRIVE_EVENT_LOGGER_H_
#include <stddef.h>
#include <string>
#include <vector>
#include "base/compiler_specific.h"
#include "base/containers/circular_deque.h"
#include "base/logging.h"
#include "base/synchronization/lock.h"
#include "base/time/time.h"
namespace drive {
// The default history size used by EventLogger.
const int kDefaultHistorySize = 1000;
// EventLogger is used to collect and expose text messages for diagnosing
// behaviors of Google APIs stuff. For instance, the collected messages are
// exposed to chrome:drive-internals.
class EventLogger {
public:
// Represents a single event log.
struct Event {
Event(int id, logging::LogSeverity severity, const std::string& what);
int id; // Monotonically increasing ID starting from 0.
logging::LogSeverity severity; // Severity of the event.
base::Time when; // When the event occurred.
std::string what; // What happened.
};
// Creates an event logger that keeps the latest kDefaultHistorySize events.
EventLogger();
EventLogger(const EventLogger&) = delete;
EventLogger& operator=(const EventLogger&) = delete;
~EventLogger();
// Logs a message and its severity.
// Can be called from any thread as long as the object is alive.
void LogRawString(logging::LogSeverity severity, const std::string& what);
// Logs a message with formatting.
// Can be called from any thread as long as the object is alive.
void Log(logging::LogSeverity severity, const char* format, ...)
PRINTF_FORMAT(3, 4);
// Sets the history size. The existing history is cleared.
// Can be called from any thread as long as the object is alive.
void SetHistorySize(size_t history_size);
// Gets the list of latest events (the oldest event comes first).
// Can be called from any thread as long as the object is alive.
std::vector<Event> GetHistory();
private:
base::circular_deque<Event> history_; // guarded by lock_.
size_t history_size_; // guarded by lock_.
int next_event_id_; // guarded by lock_.
base::Lock lock_;
};
} // namespace drive
#endif // COMPONENTS_DRIVE_EVENT_LOGGER_H_
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