1 files changed, 70 insertions, 0 deletions
diff --git a/xpcom/base/nsCycleCollectionTraversalCallback.h b/xpcom/base/nsCycleCollectionTraversalCallback.h
new file mode 100644
index 0000000000..9317a5e23a
--- /dev/null
+++ b/xpcom/base/nsCycleCollectionTraversalCallback.h
@@ -0,0 +1,70 @@
+/* -*- 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 nsCycleCollectionTraversalCallback_h__
+#define nsCycleCollectionTraversalCallback_h__
+
+#include <cstdint>
+#include "nscore.h"
+
+class nsCycleCollectionParticipant;
+class nsISupports;
+class JSObject;
+
+namespace JS {
+class GCCellPtr;
+}
+
+class NS_NO_VTABLE nsCycleCollectionTraversalCallback {
+ public:
+  // You must call DescribeRefCountedNode() with an accurate
+  // refcount, otherwise cycle collection will fail, and probably crash.
+  // If the callback cares about objname, it should put
+  // WANT_DEBUG_INFO in mFlags.
+  NS_IMETHOD_(void)
+  DescribeRefCountedNode(nsrefcnt aRefcount, const char* aObjName) = 0;
+  // Note, aCompartmentAddress is 0 if it is unknown.
+  NS_IMETHOD_(void)
+  DescribeGCedNode(bool aIsMarked, const char* aObjName,
+                   uint64_t aCompartmentAddress = 0) = 0;
+
+  NS_IMETHOD_(void) NoteXPCOMChild(nsISupports* aChild) = 0;
+  NS_IMETHOD_(void) NoteJSChild(JS::GCCellPtr aThing) = 0;
+  NS_IMETHOD_(void)
+  NoteNativeChild(void* aChild, nsCycleCollectionParticipant* aHelper) = 0;
+
+  NS_IMETHOD_(void)
+  NoteWeakMapping(JSObject* aKey, nsISupports* aVal,
+                  nsCycleCollectionParticipant* aValParticipant) = 0;
+
+  // Give a name to the edge associated with the next call to
+  // NoteXPCOMChild, NoteJSObject, NoteJSScript, or NoteNativeChild.
+  // Callbacks who care about this should set WANT_DEBUG_INFO in the
+  // flags.
+  NS_IMETHOD_(void) NoteNextEdgeName(const char* aName) = 0;
+
+  enum {
+    // Values for flags:
+
+    // Caller should call NoteNextEdgeName and pass useful objName
+    // to DescribeRefCountedNode and DescribeGCedNode.
+    WANT_DEBUG_INFO = (1 << 0),
+
+    // Caller should not skip objects that we know will be
+    // uncollectable.
+    WANT_ALL_TRACES = (1 << 1)
+  };
+  uint32_t Flags() const { return mFlags; }
+  bool WantDebugInfo() const { return (mFlags & WANT_DEBUG_INFO) != 0; }
+  bool WantAllTraces() const { return (mFlags & WANT_ALL_TRACES) != 0; }
+
+ protected:
+  nsCycleCollectionTraversalCallback() : mFlags(0) {}
+
+  uint32_t mFlags;
+};
+
+#endif  // nsCycleCollectionTraversalCallback_h__