Home | History | Annotate | Download | only in drive
      1 // Copyright (c) 2012 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 CHROME_BROWSER_DRIVE_EVENT_LOGGER_H_
      6 #define CHROME_BROWSER_DRIVE_EVENT_LOGGER_H_
      7 
      8 #include <deque>
      9 #include <string>
     10 #include <vector>
     11 
     12 #include "base/basictypes.h"
     13 #include "base/compiler_specific.h"
     14 #include "base/logging.h"
     15 #include "base/synchronization/lock.h"
     16 #include "base/time/time.h"
     17 
     18 namespace drive {
     19 
     20 // The default history size used by EventLogger.
     21 const int kDefaultHistorySize = 1000;
     22 
     23 // EventLogger is used to collect and expose text messages for diagnosing
     24 // behaviors of Google APIs stuff. For instance, the collected messages are
     25 // exposed to chrome:drive-internals.
     26 class EventLogger {
     27  public:
     28   // Represents a single event log.
     29   struct Event {
     30     Event(int id, logging::LogSeverity severity, const std::string& what);
     31     int id;  // Monotonically increasing ID starting from 0.
     32     logging::LogSeverity severity;  // Severity of the event.
     33     base::Time when;  // When the event occurred.
     34     std::string what;  // What happened.
     35   };
     36 
     37   // Creates an event logger that keeps the latest kDefaultHistorySize events.
     38   EventLogger();
     39   ~EventLogger();
     40 
     41   // Logs a message and its severity.
     42   // Can be called from any thread as long as the object is alive.
     43   void Log(logging::LogSeverity severity, const std::string& what);
     44 
     45   // Sets the history size. The existing history is cleared.
     46   // Can be called from any thread as long as the object is alive.
     47   void SetHistorySize(size_t history_size);
     48 
     49   // Gets the list of latest events (the oldest event comes first).
     50   // Can be called from any thread as long as the object is alive.
     51   std::vector<Event> GetHistory();
     52 
     53  private:
     54   std::deque<Event> history_;  // guarded by lock_.
     55   size_t history_size_;  // guarded by lock_.
     56   int next_event_id_;  // guarded by lock_.
     57   base::Lock lock_;
     58 
     59   DISALLOW_COPY_AND_ASSIGN(EventLogger);
     60 };
     61 
     62 }  // namespace drive
     63 
     64 #endif  // CHROME_BROWSER_DRIVE_EVENT_LOGGER_H_
     65