| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| // |
| // Declaration of a Windows event trace consumer base class. |
| #ifndef BASE_WIN_EVENT_TRACE_CONSUMER_H_ |
| #define BASE_WIN_EVENT_TRACE_CONSUMER_H_ |
| |
| #include <windows.h> |
| #include <wmistr.h> |
| #include <evntrace.h> |
| #include <vector> |
| #include "base/basictypes.h" |
| |
| namespace base { |
| namespace win { |
| |
| // This class is a base class that makes it easier to consume events |
| // from realtime or file sessions. Concrete consumers need to sublass |
| // a specialization of this class and override the ProcessEvent and/or |
| // the ProcessBuffer methods to implement the event consumption logic. |
| // Usage might look like: |
| // class MyConsumer: public EtwTraceConsumerBase<MyConsumer, 1> { |
| // protected: |
| // static VOID WINAPI ProcessEvent(PEVENT_TRACE event); |
| // }; |
| // |
| // MyConsumer consumer; |
| // consumer.OpenFileSession(file_path); |
| // consumer.Consume(); |
| template <class ImplClass> |
| class EtwTraceConsumerBase { |
| public: |
| // Constructs a closed consumer. |
| EtwTraceConsumerBase() { |
| } |
| |
| ~EtwTraceConsumerBase() { |
| Close(); |
| } |
| |
| // Opens the named realtime session, which must be existent. |
| // Note: You can use OpenRealtimeSession or OpenFileSession |
| // to open as many as MAXIMUM_WAIT_OBJECTS (63) sessions at |
| // any one time, though only one of them may be a realtime |
| // session. |
| HRESULT OpenRealtimeSession(const wchar_t* session_name); |
| |
| // Opens the event trace log in "file_name", which must be a full or |
| // relative path to an existing event trace log file. |
| // Note: You can use OpenRealtimeSession or OpenFileSession |
| // to open as many as kNumSessions at any one time. |
| HRESULT OpenFileSession(const wchar_t* file_name); |
| |
| // Consume all open sessions from beginning to end. |
| HRESULT Consume(); |
| |
| // Close all open sessions. |
| HRESULT Close(); |
| |
| protected: |
| // Override in subclasses to handle events. |
| static void ProcessEvent(EVENT_TRACE* event) { |
| } |
| // Override in subclasses to handle buffers. |
| static bool ProcessBuffer(EVENT_TRACE_LOGFILE* buffer) { |
| return true; // keep going |
| } |
| |
| protected: |
| // Currently open sessions. |
| std::vector<TRACEHANDLE> trace_handles_; |
| |
| private: |
| // These delegate to ImplClass callbacks with saner signatures. |
| static void WINAPI ProcessEventCallback(EVENT_TRACE* event) { |
| ImplClass::ProcessEvent(event); |
| } |
| static ULONG WINAPI ProcessBufferCallback(PEVENT_TRACE_LOGFILE buffer) { |
| return ImplClass::ProcessBuffer(buffer); |
| } |
| |
| DISALLOW_COPY_AND_ASSIGN(EtwTraceConsumerBase); |
| }; |
| |
| template <class ImplClass> inline |
| HRESULT EtwTraceConsumerBase<ImplClass>::OpenRealtimeSession( |
| const wchar_t* session_name) { |
| EVENT_TRACE_LOGFILE logfile = {}; |
| logfile.LoggerName = const_cast<wchar_t*>(session_name); |
| logfile.LogFileMode = EVENT_TRACE_REAL_TIME_MODE; |
| logfile.BufferCallback = &ProcessBufferCallback; |
| logfile.EventCallback = &ProcessEventCallback; |
| logfile.Context = this; |
| TRACEHANDLE trace_handle = ::OpenTrace(&logfile); |
| if (reinterpret_cast<TRACEHANDLE>(INVALID_HANDLE_VALUE) == trace_handle) |
| return HRESULT_FROM_WIN32(::GetLastError()); |
| |
| trace_handles_.push_back(trace_handle); |
| return S_OK; |
| } |
| |
| template <class ImplClass> inline |
| HRESULT EtwTraceConsumerBase<ImplClass>::OpenFileSession( |
| const wchar_t* file_name) { |
| EVENT_TRACE_LOGFILE logfile = {}; |
| logfile.LogFileName = const_cast<wchar_t*>(file_name); |
| logfile.BufferCallback = &ProcessBufferCallback; |
| logfile.EventCallback = &ProcessEventCallback; |
| logfile.Context = this; |
| TRACEHANDLE trace_handle = ::OpenTrace(&logfile); |
| if (reinterpret_cast<TRACEHANDLE>(INVALID_HANDLE_VALUE) == trace_handle) |
| return HRESULT_FROM_WIN32(::GetLastError()); |
| |
| trace_handles_.push_back(trace_handle); |
| return S_OK; |
| } |
| |
| template <class ImplClass> inline |
| HRESULT EtwTraceConsumerBase<ImplClass>::Consume() { |
| ULONG err = ::ProcessTrace(&trace_handles_[0], |
| trace_handles_.size(), |
| NULL, |
| NULL); |
| return HRESULT_FROM_WIN32(err); |
| } |
| |
| template <class ImplClass> inline |
| HRESULT EtwTraceConsumerBase<ImplClass>::Close() { |
| HRESULT hr = S_OK; |
| for (size_t i = 0; i < trace_handles_.size(); ++i) { |
| if (NULL != trace_handles_[i]) { |
| ULONG ret = ::CloseTrace(trace_handles_[i]); |
| trace_handles_[i] = NULL; |
| |
| if (FAILED(HRESULT_FROM_WIN32(ret))) |
| hr = HRESULT_FROM_WIN32(ret); |
| } |
| } |
| trace_handles_.clear(); |
| |
| return hr; |
| } |
| |
| } // namespace win |
| } // namespace base |
| |
| #endif // BASE_WIN_EVENT_TRACE_CONSUMER_H_ |