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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 // Declaration of a Windows event trace consumer base class. | |
| 6 #ifndef BASE_WIN_EVENT_TRACE_CONSUMER_H_ | |
| 7 #define BASE_WIN_EVENT_TRACE_CONSUMER_H_ | |
| 8 | |
| 9 #include <windows.h> | |
| 10 #include <wmistr.h> | |
| 11 #include <evntrace.h> | |
| 12 #include <vector> | |
| 13 #include "base/basictypes.h" | |
| 14 | |
| 15 namespace base { | |
| 16 namespace win { | |
| 17 | |
| 18 // This class is a base class that makes it easier to consume events | |
| 19 // from realtime or file sessions. Concrete consumers need to subclass | |
| 20 // a specialization of this class and override the ProcessEvent and/or | |
| 21 // the ProcessBuffer methods to implement the event consumption logic. | |
| 22 // Usage might look like: | |
| 23 // class MyConsumer: public EtwTraceConsumerBase<MyConsumer, 1> { | |
| 24 // protected: | |
| 25 // static VOID WINAPI ProcessEvent(PEVENT_TRACE event); | |
| 26 // }; | |
| 27 // | |
| 28 // MyConsumer consumer; | |
| 29 // consumer.OpenFileSession(file_path); | |
| 30 // consumer.Consume(); | |
| 31 template <class ImplClass> | |
| 32 class EtwTraceConsumerBase { | |
| 33 public: | |
| 34 // Constructs a closed consumer. | |
| 35 EtwTraceConsumerBase() { | |
| 36 } | |
| 37 | |
| 38 ~EtwTraceConsumerBase() { | |
| 39 Close(); | |
| 40 } | |
| 41 | |
| 42 // Opens the named realtime session, which must be existent. | |
| 43 // Note: You can use OpenRealtimeSession or OpenFileSession | |
| 44 // to open as many as MAXIMUM_WAIT_OBJECTS (63) sessions at | |
| 45 // any one time, though only one of them may be a realtime | |
| 46 // session. | |
| 47 HRESULT OpenRealtimeSession(const wchar_t* session_name); | |
| 48 | |
| 49 // Opens the event trace log in "file_name", which must be a full or | |
| 50 // relative path to an existing event trace log file. | |
| 51 // Note: You can use OpenRealtimeSession or OpenFileSession | |
| 52 // to open as many as kNumSessions at any one time. | |
| 53 HRESULT OpenFileSession(const wchar_t* file_name); | |
| 54 | |
| 55 // Consume all open sessions from beginning to end. | |
| 56 HRESULT Consume(); | |
| 57 | |
| 58 // Close all open sessions. | |
| 59 HRESULT Close(); | |
| 60 | |
| 61 protected: | |
| 62 // Override in subclasses to handle events. | |
| 63 static void ProcessEvent(EVENT_TRACE* event) { | |
| 64 } | |
| 65 // Override in subclasses to handle buffers. | |
| 66 static bool ProcessBuffer(EVENT_TRACE_LOGFILE* buffer) { | |
| 67 return true; // keep going | |
| 68 } | |
| 69 | |
| 70 protected: | |
| 71 // Currently open sessions. | |
| 72 std::vector<TRACEHANDLE> trace_handles_; | |
| 73 | |
| 74 private: | |
| 75 // These delegate to ImplClass callbacks with saner signatures. | |
| 76 static void WINAPI ProcessEventCallback(EVENT_TRACE* event) { | |
| 77 ImplClass::ProcessEvent(event); | |
| 78 } | |
| 79 static ULONG WINAPI ProcessBufferCallback(PEVENT_TRACE_LOGFILE buffer) { | |
| 80 return ImplClass::ProcessBuffer(buffer); | |
| 81 } | |
| 82 | |
| 83 DISALLOW_COPY_AND_ASSIGN(EtwTraceConsumerBase); | |
| 84 }; | |
| 85 | |
| 86 template <class ImplClass> inline | |
| 87 HRESULT EtwTraceConsumerBase<ImplClass>::OpenRealtimeSession( | |
| 88 const wchar_t* session_name) { | |
| 89 EVENT_TRACE_LOGFILE logfile = {}; | |
| 90 logfile.LoggerName = const_cast<wchar_t*>(session_name); | |
| 91 logfile.LogFileMode = EVENT_TRACE_REAL_TIME_MODE; | |
| 92 logfile.BufferCallback = &ProcessBufferCallback; | |
| 93 logfile.EventCallback = &ProcessEventCallback; | |
| 94 logfile.Context = this; | |
| 95 TRACEHANDLE trace_handle = ::OpenTrace(&logfile); | |
| 96 if (reinterpret_cast<TRACEHANDLE>(INVALID_HANDLE_VALUE) == trace_handle) | |
| 97 return HRESULT_FROM_WIN32(::GetLastError()); | |
| 98 | |
| 99 trace_handles_.push_back(trace_handle); | |
| 100 return S_OK; | |
| 101 } | |
| 102 | |
| 103 template <class ImplClass> inline | |
| 104 HRESULT EtwTraceConsumerBase<ImplClass>::OpenFileSession( | |
| 105 const wchar_t* file_name) { | |
| 106 EVENT_TRACE_LOGFILE logfile = {}; | |
| 107 logfile.LogFileName = const_cast<wchar_t*>(file_name); | |
| 108 logfile.BufferCallback = &ProcessBufferCallback; | |
| 109 logfile.EventCallback = &ProcessEventCallback; | |
| 110 logfile.Context = this; | |
| 111 TRACEHANDLE trace_handle = ::OpenTrace(&logfile); | |
| 112 if (reinterpret_cast<TRACEHANDLE>(INVALID_HANDLE_VALUE) == trace_handle) | |
| 113 return HRESULT_FROM_WIN32(::GetLastError()); | |
| 114 | |
| 115 trace_handles_.push_back(trace_handle); | |
| 116 return S_OK; | |
| 117 } | |
| 118 | |
| 119 template <class ImplClass> inline | |
| 120 HRESULT EtwTraceConsumerBase<ImplClass>::Consume() { | |
| 121 ULONG err = ::ProcessTrace(&trace_handles_[0], | |
| 122 static_cast<ULONG>(trace_handles_.size()), | |
| 123 NULL, | |
| 124 NULL); | |
| 125 return HRESULT_FROM_WIN32(err); | |
| 126 } | |
| 127 | |
| 128 template <class ImplClass> inline | |
| 129 HRESULT EtwTraceConsumerBase<ImplClass>::Close() { | |
| 130 HRESULT hr = S_OK; | |
| 131 for (size_t i = 0; i < trace_handles_.size(); ++i) { | |
| 132 if (NULL != trace_handles_[i]) { | |
| 133 ULONG ret = ::CloseTrace(trace_handles_[i]); | |
| 134 trace_handles_[i] = NULL; | |
| 135 | |
| 136 if (FAILED(HRESULT_FROM_WIN32(ret))) | |
| 137 hr = HRESULT_FROM_WIN32(ret); | |
| 138 } | |
| 139 } | |
| 140 trace_handles_.clear(); | |
| 141 | |
| 142 return hr; | |
| 143 } | |
| 144 | |
| 145 } // namespace win | |
| 146 } // namespace base | |
| 147 | |
| 148 #endif // BASE_WIN_EVENT_TRACE_CONSUMER_H_ | |
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