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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 BASE_LOGGING_WIN_H_
6 #define BASE_LOGGING_WIN_H_
7 
8 #include <string>
9 
10 #include "base/base_export.h"
11 #include "base/basictypes.h"
12 #include "base/win/event_trace_provider.h"
13 #include "base/logging.h"
14 
15 template <typename Type>
16 struct StaticMemorySingletonTraits;
17 
18 namespace logging {
19 
20 // Event ID for the log messages we generate.
21 EXTERN_C BASE_EXPORT const GUID kLogEventId;
22 
23 // Feature enable mask for LogEventProvider.
24 enum LogEnableMask {
25   // If this bit is set in our provider enable mask, we will include
26   // a stack trace with every log message.
27   ENABLE_STACK_TRACE_CAPTURE = 0x0001,
28   // If this bit is set in our provider enable mask, the provider will log
29   // a LOG message with only the textual content of the message, and no
30   // stack trace.
31   ENABLE_LOG_MESSAGE_ONLY = 0x0002,
32 };
33 
34 // The message types our log event provider generates.
35 // ETW likes user message types to start at 10.
36 enum LogMessageTypes {
37   // A textual only log message, contains a zero-terminated string.
38   LOG_MESSAGE = 10,
39   // A message with a stack trace, followed by the zero-terminated
40   // message text.
41   LOG_MESSAGE_WITH_STACKTRACE = 11,
42   // A message with:
43   //  a stack trace,
44   //  the line number as a four byte integer,
45   //  the file as a zero terminated UTF8 string,
46   //  the zero-terminated UTF8 message text.
47   LOG_MESSAGE_FULL = 12,
48 };
49 
50 // Trace provider class to drive log control and transport
51 // with Event Tracing for Windows.
52 class BASE_EXPORT LogEventProvider : public base::win::EtwTraceProvider {
53  public:
54   static LogEventProvider* GetInstance();
55 
56   static bool LogMessage(logging::LogSeverity severity, const char* file,
57       int line, size_t message_start, const std::string& str);
58 
59   static void Initialize(const GUID& provider_name);
60   static void Uninitialize();
61 
62  protected:
63   // Overridden to manipulate the log level on ETW control callbacks.
64   virtual void OnEventsEnabled();
65   virtual void OnEventsDisabled();
66 
67  private:
68   LogEventProvider();
69 
70   // The log severity prior to OnEventsEnabled,
71   // restored in OnEventsDisabled.
72   logging::LogSeverity old_log_level_;
73 
74   friend struct StaticMemorySingletonTraits<LogEventProvider>;
75   DISALLOW_COPY_AND_ASSIGN(LogEventProvider);
76 };
77 
78 }  // namespace logging
79 
80 #endif  // BASE_LOGGING_WIN_H_
81