1 files changed, 198 insertions, 0 deletions
diff --git a/xpcom/build/perfprobe.h b/xpcom/build/perfprobe.h
new file mode 100644
index 0000000000..e5a0382322
--- /dev/null
+++ b/xpcom/build/perfprobe.h
@@ -0,0 +1,198 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * A mechanism for interacting with operating system-provided
+ * debugging/profiling tools such as Microsoft EWT/Windows Performance Toolkit.
+ */
+
+#ifndef mozilla_perfprobe_h
+#define mozilla_perfprobe_h
+
+#if !defined(XP_WIN)
+#  error "For the moment, perfprobe.h is defined only for Windows platforms"
+#endif
+
+#include "nsError.h"
+#include "nsString.h"
+#include "mozilla/Logging.h"
+#include "nsTArray.h"
+#include <windows.h>
+#undef GetStartupInfo  // Prevent Windows from polluting global namespace
+#include <wmistr.h>
+#include <evntrace.h>
+
+namespace mozilla {
+namespace probes {
+
+class ProbeManager;
+
+/**
+ * A data structure supporting a trigger operation that can be used to
+ * send information to the operating system.
+ */
+
+class Probe {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(Probe)
+
+  /**
+   * Trigger the event.
+   *
+   * Note: Can be called from any thread.
+   */
+  nsresult Trigger();
+
+ protected:
+  ~Probe(){};
+
+  Probe(const nsCID& aGUID, const nsACString& aName, ProbeManager* aManager);
+  friend class ProbeManager;
+
+ protected:
+  /**
+   * The system GUID associated to this probe. See the documentation
+   * of |ProbeManager::Make| for more details.
+   */
+  const GUID mGUID;
+
+  /**
+   * The name of this probe. See the documentation
+   * of |ProbeManager::Make| for more details.
+   */
+  const nsCString mName;
+
+  /**
+   * The ProbeManager managing this probe.
+   *
+   * Note: This is a weak reference to avoid a useless cycle.
+   */
+  class ProbeManager* mManager;
+};
+
+/**
+ * A manager for a group of probes.
+ *
+ * You can have several managers in one application, provided that they all
+ * have distinct IDs and names. However, having more than 2 is considered a bad
+ * practice.
+ */
+class ProbeManager {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(ProbeManager)
+
+  /**
+   * Create a new probe manager.
+   *
+   * This constructor should be called from the main thread.
+   *
+   * @param aApplicationUID The unique ID of the probe. Under Windows, this
+   * unique ID must have been previously registered using an external tool.
+   * See MyCategory on http://msdn.microsoft.com/en-us/library/aa364100.aspx
+   * @param aApplicationName A name for the probe. Currently used only for
+   * logging purposes. In the future, may be attached to the data sent to the
+   * operating system.
+   *
+   * Note: If two ProbeManagers are constructed with the same uid and/or name,
+   * behavior is unspecified.
+   */
+  ProbeManager(const nsCID& aApplicationUID,
+               const nsACString& aApplicationName);
+
+  /**
+   * Acquire a probe.
+   *
+   * Note: Only probes acquired before the call to SetReady are taken into
+   * account
+   * Note: Can be called only from the main thread.
+   *
+   * @param aEventUID The unique ID of the probe. Under Windows, this unique
+   * ID must have been previously registered using an external tool.
+   * See MyCategory on http://msdn.microsoft.com/en-us/library/aa364100.aspx
+   * @param aEventName A name for the probe. Currently used only for logging
+   * purposes. In the
+   * future, may be attached to the data sent to the operating system.
+   * @return Either |null| in case of error or a valid |Probe*|.
+   *
+   * Note: If this method is called twice with the same uid and/or name,
+   * behavior is undefined.
+   */
+  already_AddRefed<Probe> GetProbe(const nsCID& aEventUID,
+                                   const nsACString& aEventName);
+
+  /**
+   * Start/stop the measuring session.
+   *
+   * This method should be called from the main thread.
+   *
+   * Note that starting an already started probe manager has no effect,
+   * nor does stopping an already stopped probe manager.
+   */
+  nsresult StartSession();
+  nsresult StopSession();
+
+  /**
+   * @return true If measures are currently on, i.e. if triggering probes is any
+   * is useful. You do not have to check this before triggering a probe, unless
+   * this can avoid complex computations.
+   */
+  bool IsActive();
+
+ protected:
+  ~ProbeManager();
+
+  nsresult StartSession(nsTArray<RefPtr<Probe>>& aProbes);
+  nsresult Init(const nsCID& aApplicationUID,
+                const nsACString& aApplicationName);
+
+ protected:
+  /**
+   * `true` if a session is in activity, `false` otherwise.
+   */
+  bool mIsActive;
+
+  /**
+   * The UID of this manager.
+   * See documentation above for registration steps that you
+   * may have to take.
+   */
+  nsCID mApplicationUID;
+
+  /**
+   * The name of the application.
+   */
+  nsCString mApplicationName;
+
+  /**
+   * All the probes that have been created for this manager.
+   */
+  nsTArray<RefPtr<Probe>> mAllProbes;
+
+  /**
+   * Handle used for triggering events
+   */
+  TRACEHANDLE mSessionHandle;
+
+  /**
+   * Handle used for registration/unregistration
+   */
+  TRACEHANDLE mRegistrationHandle;
+
+  /**
+   * `true` if initialization has been performed, `false` until then.
+   */
+  bool mInitialized;
+
+  friend class Probe;  // Needs to access |mSessionHandle|
+  friend ULONG WINAPI ControlCallback(WMIDPREQUESTCODE aRequestCode,
+                                      PVOID aContext, ULONG* aReserved,
+                                      PVOID aBuffer);  // Sets |mSessionHandle|
+};
+
+}  // namespace probes
+}  // namespace mozilla
+
+#endif  // mozilla_perfprobe_h