1 files changed, 144 insertions, 0 deletions
diff --git a/gfx/layers/apz/util/CheckerboardReportService.h b/gfx/layers/apz/util/CheckerboardReportService.h
new file mode 100644
index 000000000..743b29825
--- /dev/null
+++ b/gfx/layers/apz/util/CheckerboardReportService.h
@@ -0,0 +1,144 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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_dom_CheckerboardReportService_h
+#define mozilla_dom_CheckerboardReportService_h
+
+#include <string>
+
+#include "js/TypeDecls.h" // for JSContext, JSObject
+#include "mozilla/ErrorResult.h" // for ErrorResult
+#include "mozilla/StaticPtr.h" // for StaticRefPtr
+#include "nsCOMPtr.h" // for nsCOMPtr
+#include "nsISupports.h" // for NS_INLINE_DECL_REFCOUNTING
+#include "nsWrapperCache.h" // for nsWrapperCache
+
+namespace mozilla {
+
+namespace dom {
+struct CheckerboardReport;
+}
+
+namespace layers {
+
+// CheckerboardEventStorage is a singleton that stores info on checkerboard
+// events, so that they can be accessed from about:checkerboard and visualized.
+// Note that this class is NOT threadsafe, and all methods must be called on
+// the main thread.
+class CheckerboardEventStorage
+{
+  NS_INLINE_DECL_REFCOUNTING(CheckerboardEventStorage)
+
+public:
+  /**
+   * Get the singleton instance.
+   */
+  static already_AddRefed<CheckerboardEventStorage> GetInstance();
+
+  /**
+   * Get the stored checkerboard reports.
+   */
+  void GetReports(nsTArray<dom::CheckerboardReport>& aOutReports);
+
+  /**
+   * Save a checkerboard event log, optionally dropping older ones that were
+   * less severe or less recent. Zero-severity reports may be ignored entirely.
+   */
+  static void Report(uint32_t aSeverity, const std::string& aLog);
+
+private:
+  /* Stuff for refcounted singleton */
+  CheckerboardEventStorage() {}
+  virtual ~CheckerboardEventStorage() {}
+
+  static StaticRefPtr<CheckerboardEventStorage> sInstance;
+
+  void ReportCheckerboard(uint32_t aSeverity, const std::string& aLog);
+
+private:
+  /**
+   * Struct that this class uses internally to store a checkerboard report.
+   */
+  struct CheckerboardReport {
+      uint32_t mSeverity; // if 0, this report is empty
+      int64_t mTimestamp; // microseconds since epoch, as from JS_Now()
+      std::string mLog;
+
+      CheckerboardReport()
+        : mSeverity(0)
+        , mTimestamp(0)
+      {}
+
+      CheckerboardReport(uint32_t aSeverity, int64_t aTimestamp,
+                         const std::string& aLog)
+        : mSeverity(aSeverity)
+        , mTimestamp(aTimestamp)
+        , mLog(aLog)
+      {}
+  };
+
+  // The first 5 (indices 0-4) are the most severe ones in decreasing order
+  // of severity; the next 5 (indices 5-9) are the most recent ones that are
+  // not already in the "severe" list.
+  static const int SEVERITY_MAX_INDEX = 5;
+  static const int RECENT_MAX_INDEX = 10;
+  CheckerboardReport mCheckerboardReports[RECENT_MAX_INDEX];
+};
+
+} // namespace layers
+
+namespace dom {
+
+class GlobalObject;
+
+/**
+ * CheckerboardReportService is a wrapper object that allows access to the
+ * stuff in CheckerboardEventStorage (above). We need this wrapper for proper
+ * garbage/cycle collection, since this can be accessed from JS.
+ */
+class CheckerboardReportService : public nsWrapperCache
+{
+public:
+  /**
+   * Check if the given page is allowed to access this object via the WebIDL
+   * bindings. It only returns true if the page is about:checkerboard.
+   */
+  static bool IsEnabled(JSContext* aCtx, JSObject* aGlobal);
+
+  /*
+   * Other standard WebIDL binding glue.
+   */
+
+  static already_AddRefed<CheckerboardReportService>
+    Constructor(const dom::GlobalObject& aGlobal, ErrorResult& aRv);
+
+  explicit CheckerboardReportService(nsISupports* aSupports);
+
+  JSObject* WrapObject(JSContext* aCtx, JS::Handle<JSObject*> aGivenProto) override;
+
+  nsISupports* GetParentObject();
+
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(CheckerboardReportService)
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(CheckerboardReportService)
+
+public:
+  /*
+   * The methods exposed via the webidl.
+   */
+  void GetReports(nsTArray<dom::CheckerboardReport>& aOutReports);
+  bool IsRecordingEnabled() const;
+  void SetRecordingEnabled(bool aEnabled);
+  void FlushActiveReports();
+
+private:
+  virtual ~CheckerboardReportService() {}
+
+  nsCOMPtr<nsISupports> mParent;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_layers_CheckerboardReportService_h */