1 files changed, 104 insertions, 0 deletions
diff --git a/xpcom/threads/HangAnnotations.h b/xpcom/threads/HangAnnotations.h
new file mode 100644
index 000000000..6dddbf4bb
--- /dev/null
+++ b/xpcom/threads/HangAnnotations.h
@@ -0,0 +1,104 @@
+/* -*- 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/. */
+
+#ifndef mozilla_HangAnnotations_h
+#define mozilla_HangAnnotations_h
+
+#include <set>
+
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/Vector.h"
+#include "nsString.h"
+
+namespace mozilla {
+namespace HangMonitor {
+
+/**
+ * This class declares an abstraction for a data type that encapsulates all
+ * of the annotations being reported by a registered hang Annotator.
+ */
+class HangAnnotations
+{
+public:
+  virtual ~HangAnnotations() {}
+
+  virtual void AddAnnotation(const nsAString& aName, const int32_t aData) = 0;
+  virtual void AddAnnotation(const nsAString& aName, const double aData) = 0;
+  virtual void AddAnnotation(const nsAString& aName, const nsAString& aData) = 0;
+  virtual void AddAnnotation(const nsAString& aName, const nsACString& aData) = 0;
+  virtual void AddAnnotation(const nsAString& aName, const bool aData) = 0;
+
+  class Enumerator
+  {
+  public:
+    virtual ~Enumerator() {}
+    virtual bool Next(nsAString& aOutName, nsAString& aOutValue) = 0;
+  };
+
+  virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const = 0;
+  virtual bool IsEmpty() const = 0;
+  virtual UniquePtr<Enumerator> GetEnumerator() = 0;
+};
+
+typedef UniquePtr<HangAnnotations> HangAnnotationsPtr;
+typedef Vector<HangAnnotationsPtr> HangAnnotationsVector;
+
+class Annotator
+{
+public:
+  /**
+   * NB: This function is always called by the HangMonitor thread.
+   *     Plan accordingly.
+   */
+  virtual void AnnotateHang(HangAnnotations& aAnnotations) = 0;
+};
+
+/**
+ * Registers an Annotator to be called when a hang is detected.
+ * @param aAnnotator Reference to an object that implements the
+ * HangMonitor::Annotator interface.
+ */
+void RegisterAnnotator(Annotator& aAnnotator);
+
+/**
+ * Registers an Annotator that was previously registered via RegisterAnnotator.
+ * @param aAnnotator Reference to an object that implements the
+ * HangMonitor::Annotator interface.
+ */
+void UnregisterAnnotator(Annotator& aAnnotator);
+
+/**
+ * Gathers annotations. This function should be called by ChromeHangs.
+ * @return UniquePtr to HangAnnotations object or nullptr if none.
+ */
+HangAnnotationsPtr ChromeHangAnnotatorCallout();
+
+namespace Observer {
+
+class Annotators
+{
+public:
+  Annotators();
+  ~Annotators();
+
+  bool Register(Annotator& aAnnotator);
+  bool Unregister(Annotator& aAnnotator);
+
+  HangAnnotationsPtr GatherAnnotations();
+
+private:
+  Mutex                mMutex;
+  std::set<Annotator*> mAnnotators;
+};
+
+} // namespace Observer
+
+} // namespace HangMonitor
+} // namespace mozilla
+
+#endif // mozilla_HangAnnotations_h