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1 // Copyright 2014 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 CONTENT_BROWSER_TRACING_TRACING_CONSUMER_WIN_H_
6 #define CONTENT_BROWSER_TRACING_TRACING_CONSUMER_WIN_H_
7 
8 #include "base/bind.h"
9 #include "base/memory/ref_counted_memory.h"
10 #include "base/threading/thread.h"
11 #include "base/values.h"
12 #include "base/win/event_trace_consumer.h"
13 #include "base/win/event_trace_controller.h"
14 
15 template <typename Type>
16 struct DefaultSingletonTraits;
17 
18 namespace content {
19 
20 class EtwSystemEventConsumer :
21     public base::win::EtwTraceConsumerBase<EtwSystemEventConsumer> {
22  public:
23   typedef base::Callback<void(const scoped_refptr<base::RefCountedString>&)>
24       OutputCallback;
25 
26   bool StartSystemTracing();
27   void StopSystemTracing(const OutputCallback& callback);
28 
29   // Retrieve the ETW consumer instance.
30   static EtwSystemEventConsumer* GetInstance();
31 
32  private:
33   // This allows constructor and destructor to be private and usable only
34   // by the Singleton class.
35   friend struct DefaultSingletonTraits<EtwSystemEventConsumer>;
36 
37   // Constructor.
38   EtwSystemEventConsumer();
39   virtual ~EtwSystemEventConsumer();
40 
41   void AddSyncEventToBuffer();
42   void AppendEventToBuffer(EVENT_TRACE* event);
43 
44   // Static override of EtwTraceConsumerBase::ProcessEvent.
45   // @param event the raw ETW event to process.
46   friend class base::win::EtwTraceConsumerBase<EtwSystemEventConsumer>;
47   static void ProcessEvent(EVENT_TRACE* event);
48 
49   // Request the ETW trace controller to activate the kernel tracing.
50   // returns true on success, false if the kernel tracing isn't activated.
51   bool StartKernelSessionTracing();
52 
53   // Request the ETW trace controller to deactivate the kernel tracing.
54   // @param callback the callback to call with the consumed events.
55   // @returns true on success, false if an error occurred.
56   bool StopKernelSessionTracing();
57 
58   void OnStopSystemTracingDone(
59     const OutputCallback& callback,
60     const scoped_refptr<base::RefCountedString>& result);
61 
62   void TraceAndConsumeOnThread();
63   void FlushOnThread(const OutputCallback& callback);
64 
65   scoped_ptr<base::ListValue> events_;
66   base::Thread thread_;
67   TRACEHANDLE session_handle_;
68   base::win::EtwTraceProperties properties_;
69 
70   DISALLOW_COPY_AND_ASSIGN(EtwSystemEventConsumer);
71 };
72 
73 }  // namespace content
74 
75 #endif  // CONTENT_BROWSER_TRACING_TRACING_CONSUMER_WIN_H_
76