base/trace_event/trace_event_etw_export_win.h

   1 // Copyright 2015 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 // This file contains the Windows-specific exporting to ETW.
   6 #ifndef BASE_TRACE_EVENT_TRACE_EVENT_ETW_EXPORT_WIN_H_
   7 #define BASE_TRACE_EVENT_TRACE_EVENT_ETW_EXPORT_WIN_H_
   8
   9 #include <map>
  10
  11 #include "base/base_export.h"
  12 #include "base/strings/string_piece.h"
  13 #include "base/trace_event/trace_event_impl.h"
  14
  15 namespace base {
  16
  17 template <typename Type>
  18 struct StaticMemorySingletonTraits;
  19
  20 namespace trace_event {
  21
  22 class BASE_EXPORT TraceEventETWExport {
  23  public:
  24   ~TraceEventETWExport();
  25
  26   // Retrieves the singleton.
  27   // Note that this may return NULL post-AtExit processing.
  28   static TraceEventETWExport* GetInstance();
  29
  30   // Enables/disables exporting of events to ETW. If disabled,
  31   // AddEvent and AddCustomEvent will simply return when called.
  32   static void EnableETWExport();
  33   static void DisableETWExport();
  34
  35   // Returns true if ETW is enabled. For now, this is true if the command line
  36   // flag is specified.
  37   static bool IsETWExportEnabled();
  38
  39   // Exports an event to ETW. This is mainly used in
  40   // TraceLog::AddTraceEventWithThreadIdAndTimestamp to export internal events.
  41   static void AddEvent(
  42       char phase,
  43       const unsigned char* category_group_enabled,
  44       const char* name,
  45       unsigned long long id,
  46       int num_args,
  47       const char** arg_names,
  48       const unsigned char* arg_types,
  49       const unsigned long long* arg_values,
  50       const scoped_refptr<ConvertableToTraceFormat>* convertable_values);
  51
  52   // Exports an event to ETW. This should be used when exporting an event only
  53   // to ETW. Supports three arguments to be passed to ETW.
  54   // TODO(georgesak): Allow different providers.
  55   static void AddCustomEvent(const char* name,
  56                              const char* phase,
  57                              const char* arg_name_1,
  58                              const char* arg_value_1,
  59                              const char* arg_name_2,
  60                              const char* arg_value_2,
  61                              const char* arg_name_3,
  62                              const char* arg_value_3);
  63
  64   // Returns true if any category in the group is enabled.
  65   static bool IsCategoryGroupEnabled(const char* category_group_name);
  66
  67  private:
  68   // Ensure only the provider can construct us.
  69   friend struct StaticMemorySingletonTraits<TraceEventETWExport>;
  70   // To have access to UpdateKeyword().
  71   class ETWKeywordUpdateThread;
  72   TraceEventETWExport();
  73
  74   // Updates the list of enabled categories by consulting the ETW keyword.
  75   // Returns true if there was a change, false otherwise.
  76   bool UpdateEnabledCategories();
  77
  78   // Returns true if the category is enabled.
  79   bool IsCategoryEnabled(const char* category_name) const;
  80
  81   // Called back by the update thread to check for potential changes to the
  82   // keyword.
  83   static void UpdateETWKeyword();
  84
  85   // True if ETW is enabled. Allows hiding the exporting behind a flag.
  86   bool etw_export_enabled_;
  87
  88   // Maps category names to their status (enabled/disabled).
  89   std::map<StringPiece, bool> categories_status_;
  90
  91   // Local copy of the ETW keyword.
  92   uint64 etw_match_any_keyword_;
  93
  94   // Background thread that monitors changes to the ETW keyword and updates
  95   // the enabled categories when a change occurs.
  96   scoped_ptr<ETWKeywordUpdateThread> keyword_update_thread_;
  97   PlatformThreadHandle keyword_update_thread_handle_;
  98
  99   DISALLOW_COPY_AND_ASSIGN(TraceEventETWExport);
 100 };
 101
 102 }  // namespace trace_event
 103 }  // namespace base
 104
 105 #endif  // BASE_TRACE_EVENT_TRACE_EVENT_ETW_EXPORT_WIN_H_