Move Windows-specific Event Tracing for Windows implementation to base/win. ...

base/event_trace_provider_win.h

-// Copyright (c) 2009 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 provider class, to allow using
-// Windows Event Tracing for logging transport and control.
-#ifndef BASE_EVENT_TRACE_PROVIDER_WIN_H_
-#define BASE_EVENT_TRACE_PROVIDER_WIN_H_
-#pragma once
-
-#include <windows.h>
-#include <wmistr.h>
-#include <evntrace.h>
-#include "base/basictypes.h"
-
-typedef GUID EtwEventClass;
-typedef UCHAR EtwEventType;
-typedef UCHAR EtwEventLevel;
-typedef USHORT EtwEventVersion;
-typedef ULONG EtwEventFlags;
-
-// Base class is a POD for correctness.
-template <size_t N> struct EtwMofEventBase {
-  EVENT_TRACE_HEADER header;
-  MOF_FIELD fields[N];
-};
-
-// Utility class to auto-initialize event trace header structures.
-template <size_t N> class EtwMofEvent: public EtwMofEventBase<N> {
- public:
-  typedef EtwMofEventBase<N> Super;
-
-  EtwMofEvent() {
-    memset(static_cast<Super*>(this), 0, sizeof(Super));
-  }
-
-  EtwMofEvent(const EtwEventClass& event_class, EtwEventType type,
-              EtwEventLevel level) {
-    memset(static_cast<Super*>(this), 0, sizeof(Super));
-    header.Size = sizeof(Super);
-    header.Guid = event_class;
-    header.Class.Type = type;
-    header.Class.Level = level;
-    header.Flags = WNODE_FLAG_TRACED_GUID | WNODE_FLAG_USE_MOF_PTR;
-  }
-
-  EtwMofEvent(const EtwEventClass& event_class, EtwEventType type,
-              EtwEventVersion version, EtwEventLevel level) {
-    memset(static_cast<Super*>(this), 0, sizeof(Super));
-    header.Size = sizeof(Super);
-    header.Guid = event_class;
-    header.Class.Type = type;
-    header.Class.Version = version;
-    header.Class.Level = level;
-    header.Flags = WNODE_FLAG_TRACED_GUID | WNODE_FLAG_USE_MOF_PTR;
-  }
-
-  void SetField(int field, size_t size, const void *data) {
-    // DCHECK(field < N);
-    if ((field < N) && (size <= kuint32max)) {
-      fields[field].DataPtr = reinterpret_cast<ULONG64>(data);
-      fields[field].Length = static_cast<ULONG>(size);
-    }
-  }
-
-  EVENT_TRACE_HEADER* get() { return& header; }
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(EtwMofEvent);
-};
-
-// Trace provider with Event Tracing for Windows. The trace provider
-// registers with ETW by its name which is a GUID. ETW calls back to
-// the object whenever the trace level or enable flags for this provider
-// name changes.
-// Users of this class can test whether logging is currently enabled at
-// a particular trace level, and whether particular enable flags are set,
-// before other resources are consumed to generate and issue the log
-// messages themselves.
-class EtwTraceProvider {
- public:
-  // Creates an event trace provider identified by provider_name, which
-  // will be the name registered with Event Tracing for Windows (ETW).
-  explicit EtwTraceProvider(const GUID& provider_name);
-
-  // Creates an unnamed event trace provider, the provider must be given
-  // a name before registration.
-  EtwTraceProvider();
-  virtual ~EtwTraceProvider();
-
-  // Registers the trace provider with Event Tracing for Windows.
-  // Note: from this point forward ETW may call the provider's control
-  //    callback. If the provider's name is enabled in some trace session
-  //    already, the callback may occur recursively from this call, so
-  //    call this only when you're ready to handle callbacks.
-  ULONG Register();
-  // Unregisters the trace provider with ETW.
-  ULONG Unregister();
-
-  // Accessors.
-  void set_provider_name(const GUID& provider_name) {
-    provider_name_ = provider_name;
-  }
-  const GUID& provider_name() const { return provider_name_; }
-  TRACEHANDLE registration_handle() const { return registration_handle_; }
-  TRACEHANDLE session_handle() const { return session_handle_; }
-  EtwEventFlags enable_flags() const { return enable_flags_; }
-  EtwEventLevel enable_level() const { return enable_level_; }
-
-  // Returns true iff logging should be performed for "level" and "flags".
-  // Note: flags is treated as a bitmask, and should normally have a single
-  //      bit set, to test whether to log for a particular sub "facility".
-  bool ShouldLog(EtwEventLevel level, EtwEventFlags flags) {
-    return NULL != session_handle_ && level >= enable_level_ &&
-        (0 != (flags & enable_flags_));
-  }
-
-  // Simple wrappers to log Unicode and ANSI strings.
-  // Do nothing if !ShouldLog(level, 0xFFFFFFFF).
-  ULONG Log(const EtwEventClass& event_class, EtwEventType type,
-            EtwEventLevel level, const char *message);
-  ULONG Log(const EtwEventClass& event_class, EtwEventType type,
-            EtwEventLevel level, const wchar_t *message);
-
-  // Log the provided event.
-  ULONG Log(EVENT_TRACE_HEADER* event);
-
- protected:
-  // Called after events have been enabled, override in subclasses
-  // to set up state or log at the start of a session.
-  // Note: This function may be called ETW's thread and may be racy,
-  //    bring your own locking if needed.
-  virtual void OnEventsEnabled() {}
-
-  // Called just before events are disabled, override in subclasses
-  // to tear down state or log at the end of a session.
-  // Note: This function may be called ETW's thread and may be racy,
-  //    bring your own locking if needed.
-  virtual void OnEventsDisabled() {}
-
-  // Called just after events have been disabled, override in subclasses
-  // to tear down state at the end of a session. At this point it's
-  // to late to log anything to the session.
-  // Note: This function may be called ETW's thread and may be racy,
-  //    bring your own locking if needed.
-  virtual void PostEventsDisabled() {}
-
- private:
-  ULONG EnableEvents(PVOID buffer);
-  ULONG DisableEvents();
-  ULONG Callback(WMIDPREQUESTCODE request, PVOID buffer);
-  static ULONG WINAPI ControlCallback(WMIDPREQUESTCODE request, PVOID context,
-                                      ULONG *reserved, PVOID buffer);
-
-  GUID provider_name_;
-  TRACEHANDLE registration_handle_;
-  TRACEHANDLE session_handle_;
-  EtwEventFlags enable_flags_;
-  EtwEventLevel enable_level_;
-
-  // We don't use this, but on XP we're obliged to pass one in to
-  // RegisterTraceGuids. Non-const, because that's how the API needs it.
-  static TRACE_GUID_REGISTRATION obligatory_guid_registration_;
-
-  DISALLOW_COPY_AND_ASSIGN(EtwTraceProvider);
-};
-
-#endif  // BASE_EVENT_TRACE_PROVIDER_WIN_H_