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      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 CHROMEOS_NETWORK_NETWORK_EVENT_LOG_H_
      6 #define CHROMEOS_NETWORK_NETWORK_EVENT_LOG_H_
      7 
      8 #include <deque>
      9 #include <string>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/strings/stringprintf.h"
     13 #include "base/time/time.h"
     14 #include "chromeos/chromeos_export.h"
     15 
     16 namespace base {
     17 class Value;
     18 }
     19 
     20 namespace chromeos {
     21 
     22 // Namespace for functions for logging network events.
     23 namespace network_event_log {
     24 
     25 // Used to determine which order to output event entries in GetAsString.
     26 enum StringOrder {
     27   OLDEST_FIRST,
     28   NEWEST_FIRST
     29 };
     30 
     31 // Used to set the detail level for logging.
     32 enum LogLevel {
     33   LOG_LEVEL_ERROR = 0,
     34   LOG_LEVEL_USER = 1,
     35   LOG_LEVEL_EVENT = 2,
     36   LOG_LEVEL_DEBUG = 3
     37 };
     38 
     39 // Default log level.
     40 CHROMEOS_EXPORT extern const LogLevel kDefaultLogLevel;
     41 
     42 // Initializes / shuts down network event logging. Calling Initialize more than
     43 // once will reset the log.
     44 CHROMEOS_EXPORT void Initialize();
     45 CHROMEOS_EXPORT void Shutdown();
     46 
     47 // Returns true if network event logging has been initialized.
     48 CHROMEOS_EXPORT bool IsInitialized();
     49 
     50 namespace internal {
     51 
     52 // Gets the maximum number of log entries.
     53 CHROMEOS_EXPORT size_t GetMaxLogEntries();
     54 
     55 // Sets the maximum number of entries to something other than the default. If
     56 // |max_entries| is less than the current maximum number of entries, this will
     57 // delete any existing entries in excess of |max_entries|.
     58 CHROMEOS_EXPORT void SetMaxLogEntries(size_t max_entries);
     59 
     60 // Adds an entry to the event log at level specified by |log_level|.
     61 // A maximum number of events are recorded after which new events replace
     62 // old ones. Error events are prioritized such that error events will only be
     63 // deleted if more than least half of the entries are errors (at which point
     64 // the oldest error entry will be replaced). Does nothing unless Initialize()
     65 // has been called. NOTE: Generally use NET_LOG instead.
     66 CHROMEOS_EXPORT void AddEntry(const char* file,
     67                               int file_line,
     68                               LogLevel log_level,
     69                               const std::string& event,
     70                               const std::string& description);
     71 
     72 }  // namespace internal
     73 
     74 // Outputs the log to a formatted string.
     75 // |order| determines which order to output the events.
     76 // |format| is a string that determines which elements to show. Elements
     77 // must be comma-separated, e.g. "time,desc".
     78 // Note: order of the format strings does not affect the output.
     79 //  "time" - Include a timestamp.
     80 //  "file" - Include file and line number.
     81 //  "desc" - Include the description.
     82 //  "html" - Include html tags.
     83 // Only events with |log_level| <= |max_level| are included in the output.
     84 // If |max_events| > 0, limits how many events are output.
     85 CHROMEOS_EXPORT std::string GetAsString(StringOrder order,
     86                                         const std::string& format,
     87                                         LogLevel max_level,
     88                                         size_t max_events);
     89 
     90 // Helper function for displaying a value as a string.
     91 CHROMEOS_EXPORT std::string ValueAsString(const base::Value& value);
     92 
     93 // Errors
     94 #define NET_LOG_ERROR(event, desc) NET_LOG_LEVEL(                       \
     95     ::chromeos::network_event_log::LOG_LEVEL_ERROR, event, desc)
     96 
     97 // Chrome initiated events, e.g. connection requests, scan requests,
     98 // configuration removal (either from the UI or from ONC policy application).
     99 #define NET_LOG_USER(event, desc) NET_LOG_LEVEL(                        \
    100     ::chromeos::network_event_log::LOG_LEVEL_USER, event, desc)
    101 
    102 // Important events, e.g. state updates
    103 #define NET_LOG_EVENT(event, desc) NET_LOG_LEVEL(                       \
    104     ::chromeos::network_event_log::LOG_LEVEL_EVENT, event, desc)
    105 
    106 // Non-essential debugging events
    107 #define NET_LOG_DEBUG(event, desc) NET_LOG_LEVEL(                       \
    108     ::chromeos::network_event_log::LOG_LEVEL_DEBUG, event, desc)
    109 
    110 // Macro to include file and line number info in the event log.
    111 #define NET_LOG_LEVEL(log_level, event, description)            \
    112   ::chromeos::network_event_log::internal::AddEntry(            \
    113       __FILE__, __LINE__, log_level, event, description)
    114 
    115 }  // namespace network_event_log
    116 
    117 }  // namespace chromeos
    118 
    119 #endif  // CHROMEOS_NETWORK_NETWORK_EVENT_LOG_H_
    120