base/debug/trace_event_win.h

   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 // This file contains the Windows-specific declarations for trace_event.h.
   6 #ifndef BASE_DEBUG_TRACE_EVENT_WIN_H_
   7 #define BASE_DEBUG_TRACE_EVENT_WIN_H_
   8
   9 #include <string>
  10
  11 #include "base/base_export.h"
  12 #include "base/debug/trace_event.h"
  13 #include "base/win/event_trace_provider.h"
  14
  15 // Fwd.
  16 template <typename Type>
  17 struct StaticMemorySingletonTraits;
  18
  19 namespace base {
  20 namespace debug {
  21
  22 // This EtwTraceProvider subclass implements ETW logging
  23 // for the macros above on Windows.
  24 class BASE_EXPORT TraceEventETWProvider : public base::win::EtwTraceProvider {
  25  public:
  26   // Start logging trace events.
  27   // This is a noop in this implementation.
  28   static bool StartTracing();
  29
  30   // Trace begin/end/instant events, this is the bottleneck implementation
  31   // all the others defer to.
  32   // Allowing the use of std::string for name or extra is a convenience,
  33   // whereas passing name or extra as a const char* avoids the construction
  34   // of temporary std::string instances.
  35   // If -1 is passed for name_len or extra_len, the strlen of the string will
  36   // be used for length.
  37   static void Trace(const char* name,
  38                     size_t name_len,
  39                     char type,
  40                     const void* id,
  41                     const char* extra,
  42                     size_t extra_len);
  43
  44   // Allows passing extra as a std::string for convenience.
  45   static void Trace(const char* name,
  46                     char type,
  47                     const void* id,
  48                     const std::string& extra) {
  49     return Trace(name, -1, type, id, extra.c_str(), extra.length());
  50   }
  51
  52   // Allows passing extra as a const char* to avoid constructing temporary
  53   // std::string instances where not needed.
  54   static void Trace(const char* name,
  55                     char type,
  56                     const void* id,
  57                     const char* extra) {
  58     return Trace(name, -1, type, id, extra, -1);
  59   }
  60
  61   // Retrieves the singleton.
  62   // Note that this may return NULL post-AtExit processing.
  63   static TraceEventETWProvider* GetInstance();
  64
  65   // Returns true iff tracing is turned on.
  66   bool IsTracing() {
  67     return enable_level() >= TRACE_LEVEL_INFORMATION;
  68   }
  69
  70   // Emit a trace of type |type| containing |name|, |id|, and |extra|.
  71   // Note: |name| and |extra| must be NULL, or a zero-terminated string of
  72   //    length |name_len| or |extra_len| respectively.
  73   // Note: if name_len or extra_len are -1, the length of the corresponding
  74   //    string will be used.
  75   void TraceEvent(const char* name,
  76                   size_t name_len,
  77                   char type,
  78                   const void* id,
  79                   const char* extra,
  80                   size_t extra_len);
  81
  82   // Exposed for unittesting only, allows resurrecting our
  83   // singleton instance post-AtExit processing.
  84   static void Resurrect();
  85
  86  private:
  87   // Ensure only the provider can construct us.
  88   friend struct StaticMemorySingletonTraits<TraceEventETWProvider>;
  89   TraceEventETWProvider();
  90
  91   DISALLOW_COPY_AND_ASSIGN(TraceEventETWProvider);
  92 };
  93
  94 // The ETW trace provider GUID.
  95 BASE_EXPORT extern const GUID kChromeTraceProviderName;
  96
  97 // The ETW event class GUID for 32 bit events.
  98 BASE_EXPORT extern const GUID kTraceEventClass32;
  99
 100 // The ETW event class GUID for 64 bit events.
 101 BASE_EXPORT extern const GUID kTraceEventClass64;
 102
 103 // The ETW event types, IDs 0x00-0x09 are reserved, so start at 0x10.
 104 const base::win::EtwEventType kTraceEventTypeBegin = 0x10;
 105 const base::win::EtwEventType kTraceEventTypeEnd = 0x11;
 106 const base::win::EtwEventType kTraceEventTypeInstant = 0x12;
 107
 108 // If this flag is set in enable flags
 109 enum TraceEventETWFlags {
 110   CAPTURE_STACK_TRACE = 0x0001,
 111 };
 112
 113 // The event format consists of:
 114 // The "name" string as a zero-terminated ASCII string.
 115 // The id pointer in the machine bitness.
 116 // The "extra" string as a zero-terminated ASCII string.
 117 // Optionally the stack trace, consisting of a DWORD "depth", followed
 118 //    by an array of void* (machine bitness) of length "depth".
 119
 120 }  // namespace debug
 121 }  // namespace base
 122
 123 #endif  // BASE_DEBUG_TRACE_EVENT_WIN_H_