diff -r 000000000000 -r 6474c204b198 dom/bindings/ToJSValue.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/bindings/ToJSValue.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,291 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* vim: set ts=2 sw=2 et tw=79: */
+/* 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_ToJSValue_h
+#define mozilla_dom_ToJSValue_h
+
+#include "mozilla/TypeTraits.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/dom/BindingUtils.h"
+#include "mozilla/dom/TypedArray.h"
+#include "jsapi.h"
+#include "nsISupports.h"
+#include "nsTArray.h"
+#include "nsWrapperCache.h"
+
+namespace mozilla {
+namespace dom {
+
+// If ToJSValue returns false, it must set an exception on the
+// JSContext.
+
+// Accept strings.
+bool
+ToJSValue(JSContext* aCx,
+          const nsAString& aArgument,
+          JS::MutableHandle<JS::Value> aValue);
+
+// Accept booleans.
+inline bool
+ToJSValue(JSContext* aCx,
+          bool aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  aValue.setBoolean(aArgument);
+  return true;
+}
+
+// Accept integer types
+inline bool
+ToJSValue(JSContext* aCx,
+          int32_t aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  aValue.setInt32(aArgument);
+  return true;
+}
+
+// The uint32_t version is disabled for now because on the super-old b2g
+// compiler nsresult and uint32_t are the same type.  If someone needs this at
+// some point we'll need to figure out how to make it work (e.g. by switching to
+// traits structs and using the trick IPC's ParamTraits uses, where a traits
+// struct templated on the type inherits from a base traits struct of some sort,
+// templated on the same type, or something).  Maybe b2g will update to a modern
+// compiler before that happens....
+#if 0
+inline bool
+ToJSValue(JSContext* aCx,
+          uint32_t aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  aValue.setNumber(aArgument);
+  return true;
+}
+#endif
+
+inline bool
+ToJSValue(JSContext* aCx,
+          int64_t aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  aValue.setNumber(double(aArgument));
+  return true;
+}
+
+inline bool
+ToJSValue(JSContext* aCx,
+          uint64_t aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  aValue.setNumber(double(aArgument));
+  return true;
+}
+
+// accept floating point types
+inline bool
+ToJSValue(JSContext* aCx,
+          float aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  aValue.setNumber(aArgument);
+  return true;
+}
+
+inline bool
+ToJSValue(JSContext* aCx,
+          double aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  aValue.setNumber(aArgument);
+  return true;
+}
+
+// Accept objects that inherit from nsWrapperCache and nsISupports (e.g. most
+// DOM objects).
+template <class T>
+typename EnableIf<IsBaseOf<nsWrapperCache, T>::value &&
+                  IsBaseOf<nsISupports, T>::value, bool>::Type
+ToJSValue(JSContext* aCx,
+          T& aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+  // Make sure non-webidl objects don't sneak in here
+  MOZ_ASSERT(aArgument.IsDOMBinding());
+
+  return WrapNewBindingObject(aCx, aArgument, aValue);
+}
+
+// Accept typed arrays built from appropriate nsTArray values
+template<typename T>
+typename EnableIf<IsBaseOf<AllTypedArraysBase, T>::value, bool>::Type
+ToJSValue(JSContext* aCx,
+          const TypedArrayCreator<T>& aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  JSObject* obj = aArgument.Create(aCx);
+  if (!obj) {
+    return false;
+  }
+  aValue.setObject(*obj);
+  return true;
+}
+
+// We don't want to include nsContentUtils here, so use a helper
+// function for the nsISupports case.
+namespace tojsvalue_detail {
+bool
+ISupportsToJSValue(JSContext* aCx,
+                   nsISupports* aArgument,
+                   JS::MutableHandle<JS::Value> aValue);
+} // namespace tojsvalue_detail
+
+// Accept objects that inherit from nsISupports but not nsWrapperCache (e.g.
+// nsIDOMFile).
+template <class T>
+typename EnableIf<!IsBaseOf<nsWrapperCache, T>::value &&
+                  IsBaseOf<nsISupports, T>::value, bool>::Type
+ToJSValue(JSContext* aCx,
+          T& aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  return tojsvalue_detail::ISupportsToJSValue(aCx, &aArgument, aValue);
+}
+
+// Accept nsRefPtr/nsCOMPtr
+template <typename T>
+bool
+ToJSValue(JSContext* aCx,
+          const nsCOMPtr<T>& aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  return ToJSValue(aCx, *aArgument.get(), aValue);
+}
+
+template <typename T>
+bool
+ToJSValue(JSContext* aCx,
+          const nsRefPtr<T>& aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  return ToJSValue(aCx, *aArgument.get(), aValue);
+}
+
+// Accept WebIDL dictionaries
+template <class T>
+typename EnableIf<IsBaseOf<DictionaryBase, T>::value, bool>::Type
+ToJSValue(JSContext* aCx,
+          const T& aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  return aArgument.ToObject(aCx, aValue);
+}
+
+// Accept existing JS values (which may not be same-compartment with us
+inline bool
+ToJSValue(JSContext* aCx, JS::Handle<JS::Value> aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  aValue.set(aArgument);
+  return MaybeWrapValue(aCx, aValue);
+}
+
+// Accept nsresult, for use in rejections, and create an XPCOM
+// exception object representing that nsresult.
+bool
+ToJSValue(JSContext* aCx,
+          nsresult aArgument,
+          JS::MutableHandle<JS::Value> aValue);
+
+// Accept arrays of other things we accept
+template <typename T>
+bool
+ToJSValue(JSContext* aCx,
+          T* aArguments,
+          size_t aLength,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  // Make sure we're called in a compartment
+  MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
+
+  JS::AutoValueVector v(aCx);
+  if (!v.resize(aLength)) {
+    return false;
+  }
+  for (size_t i = 0; i < aLength; ++i) {
+    if (!ToJSValue(aCx, aArguments[i], v.handleAt(i))) {
+      return false;
+    }
+  }
+  JSObject* arrayObj = JS_NewArrayObject(aCx, v);
+  if (!arrayObj) {
+    return false;
+  }
+  aValue.setObject(*arrayObj);
+  return true;
+}
+
+template <typename T>
+bool
+ToJSValue(JSContext* aCx,
+          const nsTArray<T>& aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  return ToJSValue(aCx, aArgument.Elements(),
+                   aArgument.Length(), aValue);
+}
+
+template <typename T>
+bool
+ToJSValue(JSContext* aCx,
+          const FallibleTArray<T>& aArgument,
+          JS::MutableHandle<JS::Value> aValue)
+{
+  return ToJSValue(aCx, aArgument.Elements(),
+                   aArgument.Length(), aValue);
+}
+
+template <typename T, int N>
+bool
+ToJSValue(JSContext* aCx,
+          const T(&aArgument)[N],
+          JS::MutableHandle<JS::Value> aValue)
+{
+  return ToJSValue(aCx, aArgument, N, aValue);
+}
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_ToJSValue_h */