diff -r 000000000000 -r 6474c204b198 js/src/jswatchpoint.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jswatchpoint.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,85 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * 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 jswatchpoint_h
+#define jswatchpoint_h
+
+#include "jsalloc.h"
+
+#include "gc/Barrier.h"
+#include "js/HashTable.h"
+#include "js/OldDebugAPI.h"
+
+namespace js {
+
+struct WeakMapTracer;
+
+struct WatchKey {
+    WatchKey() {}
+    WatchKey(JSObject *obj, jsid id) : object(obj), id(id) {}
+    WatchKey(const WatchKey &key) : object(key.object.get()), id(key.id.get()) {}
+    EncapsulatedPtrObject object;
+    EncapsulatedId id;
+
+    bool operator!=(const WatchKey &other) const {
+        return object != other.object || id != other.id;
+    }
+};
+
+struct Watchpoint {
+    JSWatchPointHandler handler;
+    EncapsulatedPtrObject closure;  /* This is always marked in minor GCs and so doesn't require a postbarrier. */
+    bool held;  /* true if currently running handler */
+    Watchpoint(JSWatchPointHandler handler, JSObject* closure, bool held)
+      : handler(handler), closure(closure), held(held) {}
+};
+
+template <>
+struct DefaultHasher<WatchKey>
+{
+    typedef WatchKey Lookup;
+    static inline js::HashNumber hash(const Lookup &key);
+
+    static bool match(const WatchKey &k, const Lookup &l) {
+        return k.object == l.object && k.id.get() == l.id.get();
+    }
+
+    static void rekey(WatchKey &k, const WatchKey& newKey) {
+        k.object.unsafeSet(newKey.object);
+        k.id.unsafeSet(newKey.id);
+    }
+};
+
+class WatchpointMap {
+  public:
+    typedef HashMap<WatchKey, Watchpoint, DefaultHasher<WatchKey>, SystemAllocPolicy> Map;
+
+    bool init();
+    bool watch(JSContext *cx, HandleObject obj, HandleId id,
+               JSWatchPointHandler handler, HandleObject closure);
+    void unwatch(JSObject *obj, jsid id,
+                 JSWatchPointHandler *handlerp, JSObject **closurep);
+    void unwatchObject(JSObject *obj);
+    void clear();
+
+    bool triggerWatchpoint(JSContext *cx, HandleObject obj, HandleId id, MutableHandleValue vp);
+
+    static bool markCompartmentIteratively(JSCompartment *c, JSTracer *trc);
+    bool markIteratively(JSTracer *trc);
+    void markAll(JSTracer *trc);
+    static void sweepAll(JSRuntime *rt);
+    void sweep();
+
+    static void traceAll(WeakMapTracer *trc);
+    void trace(WeakMapTracer *trc);
+
+  private:
+    Map map;
+};
+
+}
+
+#endif /* jswatchpoint_h */