diff -r 000000000000 -r 6474c204b198 js/ipc/JavaScriptShared.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/ipc/JavaScriptShared.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,141 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sw=4 et 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_jsipc_JavaScriptShared_h__
+#define mozilla_jsipc_JavaScriptShared_h__
+
+#include "mozilla/dom/DOMTypes.h"
+#include "mozilla/jsipc/PJavaScript.h"
+#include "nsJSUtils.h"
+#include "nsFrameMessageManager.h"
+
+namespace mozilla {
+namespace jsipc {
+
+typedef uint64_t ObjectId;
+
+class JavaScriptShared;
+
+class CpowIdHolder : public CpowHolder
+{
+  public:
+    CpowIdHolder(JavaScriptShared *js, const InfallibleTArray<CpowEntry> &cpows)
+      : js_(js),
+        cpows_(cpows)
+    {
+    }
+
+    bool ToObject(JSContext *cx, JS::MutableHandleObject objp);
+
+  private:
+    JavaScriptShared *js_;
+    const InfallibleTArray<CpowEntry> &cpows_;
+};
+
+// Map ids -> JSObjects
+class ObjectStore
+{
+    typedef js::DefaultHasher<ObjectId> TableKeyHasher;
+
+    typedef js::HashMap<ObjectId, JS::Heap<JSObject *>, TableKeyHasher, js::SystemAllocPolicy> ObjectTable;
+
+  public:
+    ObjectStore();
+
+    bool init();
+    void trace(JSTracer *trc);
+
+    bool add(ObjectId id, JSObject *obj);
+    JSObject *find(ObjectId id);
+    void remove(ObjectId id);
+
+  private:
+    ObjectTable table_;
+};
+
+// Map JSObjects -> ids
+class ObjectIdCache
+{
+    typedef js::PointerHasher<JSObject *, 3> Hasher;
+    typedef js::HashMap<JSObject *, ObjectId, Hasher, js::SystemAllocPolicy> ObjectIdTable;
+
+  public:
+    ObjectIdCache();
+    ~ObjectIdCache();
+
+    bool init();
+    void trace(JSTracer *trc);
+
+    bool add(JSContext *cx, JSObject *obj, ObjectId id);
+    ObjectId find(JSObject *obj);
+    void remove(JSObject *obj);
+
+  private:
+    static void keyMarkCallback(JSTracer *trc, JSObject *key, void *data);
+
+    ObjectIdTable *table_;
+};
+
+class JavaScriptShared
+{
+  public:
+    bool init();
+
+    static const uint32_t OBJECT_EXTRA_BITS  = 1;
+    static const uint32_t OBJECT_IS_CALLABLE = (1 << 0);
+
+    bool Unwrap(JSContext *cx, const InfallibleTArray<CpowEntry> &aCpows, JS::MutableHandleObject objp);
+    bool Wrap(JSContext *cx, JS::HandleObject aObj, InfallibleTArray<CpowEntry> *outCpows);
+
+  protected:
+    bool toVariant(JSContext *cx, JS::HandleValue from, JSVariant *to);
+    bool toValue(JSContext *cx, const JSVariant &from, JS::MutableHandleValue to);
+    bool fromDescriptor(JSContext *cx, JS::Handle<JSPropertyDescriptor> desc, PPropertyDescriptor *out);
+    bool toDescriptor(JSContext *cx, const PPropertyDescriptor &in,
+                      JS::MutableHandle<JSPropertyDescriptor> out);
+    bool convertIdToGeckoString(JSContext *cx, JS::HandleId id, nsString *to);
+    bool convertGeckoStringToId(JSContext *cx, const nsString &from, JS::MutableHandleId id);
+
+    bool toValue(JSContext *cx, const JSVariant &from, jsval *to) {
+        JS::RootedValue v(cx);
+        if (!toValue(cx, from, &v))
+            return false;
+        *to = v;
+        return true;
+    }
+
+    virtual bool makeId(JSContext *cx, JSObject *obj, ObjectId *idp) = 0;
+    virtual JSObject *unwrap(JSContext *cx, ObjectId id) = 0;
+
+    bool unwrap(JSContext *cx, ObjectId id, JS::MutableHandle<JSObject*> objp) {
+        if (!id) {
+            objp.set(nullptr);
+            return true;
+        }
+
+        objp.set(unwrap(cx, id));
+        return bool(objp.get());
+    }
+
+    static void ConvertID(const nsID &from, JSIID *to);
+    static void ConvertID(const JSIID &from, nsID *to);
+
+    JSObject *findObject(uint32_t objId) {
+        return objects_.find(objId);
+    }
+
+  protected:
+    ObjectStore objects_;
+};
+
+// Use 47 at most, to be safe, since jsval privates are encoded as doubles.
+static const uint64_t MAX_CPOW_IDS = (uint64_t(1) << 47) - 1;
+
+} // namespace jsipc
+} // namespace mozilla
+
+#endif