gecko-dev/dom/bindings/ToJSValue.h

460 lines
12 KiB
C++

/* -*- 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 mozilla_dom_ToJSValue_h
#define mozilla_dom_ToJSValue_h
#include "mozilla/TypeTraits.h"
#include "mozilla/Assertions.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/NonRefcountedDOMObject.h"
#include "mozilla/dom/TypedArray.h"
#include "jsapi.h"
#include "nsISupports.h"
#include "nsTArray.h"
#include "nsWrapperCache.h"
#include "nsAutoPtr.h"
namespace mozilla {
namespace dom {
class Promise;
// If ToJSValue returns false, it must set an exception on the
// JSContext.
// Accept strings.
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
const nsAString& aArgument,
JS::MutableHandle<JS::Value> aValue);
// Accept booleans. But be careful here: if we just have a function that takes
// a boolean argument, then any pointer that doesn't match one of our other
// signatures/templates will get treated as a boolean, which is clearly not
// desirable. So make this a template that only gets used if the argument type
// is actually boolean
template<typename T>
MOZ_MUST_USE
typename EnableIf<IsSame<T, bool>::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));
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;
}
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;
}
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 CallbackObjects
MOZ_MUST_USE inline bool
ToJSValue(JSContext* aCx,
CallbackObject& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
// Make sure we're called in a compartment
MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
aValue.setObjectOrNull(aArgument.Callback(aCx));
return MaybeWrapValue(aCx, aValue);
}
// Accept objects that inherit from nsWrapperCache (e.g. most
// DOM objects).
template <class T>
MOZ_MUST_USE
typename EnableIf<IsBaseOf<nsWrapperCache, 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 GetOrCreateDOMReflector(aCx, aArgument, aValue);
}
// Accept non-refcounted DOM objects that do not inherit from
// nsWrapperCache. Refcounted ones would be too much of a footgun:
// you could convert them to JS twice and get two different objects.
namespace binding_detail {
template<class T>
MOZ_MUST_USE
typename EnableIf<IsBaseOf<NonRefcountedDOMObject, T>::value, bool>::Type
ToJSValueFromPointerHelper(JSContext* aCx,
T* aArgument,
JS::MutableHandle<JS::Value> aValue)
{
// Make sure we're called in a compartment
MOZ_ASSERT(JS::CurrentGlobalOrNull(aCx));
// This is a cut-down version of
// WrapNewBindingNonWrapperCachedObject that doesn't need to deal
// with nearly as many cases.
if (!aArgument) {
aValue.setNull();
return true;
}
JS::Rooted<JSObject*> obj(aCx);
if (!aArgument->WrapObject(aCx, nullptr, &obj)) {
return false;
}
aValue.setObject(*obj);
return true;
}
} // namespace binding_detail
// We can take a non-refcounted non-wrapper-cached DOM object that lives in an
// nsAutoPtr.
template<class T>
MOZ_MUST_USE
typename EnableIf<IsBaseOf<NonRefcountedDOMObject, T>::value, bool>::Type
ToJSValue(JSContext* aCx,
nsAutoPtr<T>&& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
if (!binding_detail::ToJSValueFromPointerHelper(aCx, aArgument.get(), aValue)) {
return false;
}
// JS object took ownership
aArgument.forget();
return true;
}
// We can take a non-refcounted non-wrapper-cached DOM object that lives in a
// UniquePtr.
template<class T>
MOZ_MUST_USE
typename EnableIf<IsBaseOf<NonRefcountedDOMObject, T>::value, bool>::Type
ToJSValue(JSContext* aCx,
UniquePtr<T>&& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
if (!binding_detail::ToJSValueFromPointerHelper(aCx, aArgument.get(), aValue)) {
return false;
}
// JS object took ownership
Unused << aArgument.release();
return true;
}
// Accept typed arrays built from appropriate nsTArray values
template<typename T>
MOZ_MUST_USE
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;
}
// Accept objects that inherit from nsISupports but not nsWrapperCache (e.g.
// DOM File).
template <class T>
MOZ_MUST_USE
typename EnableIf<!IsBaseOf<nsWrapperCache, T>::value &&
!IsBaseOf<CallbackObject, 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));
xpcObjectHelper helper(ToSupports(&aArgument));
JS::Rooted<JSObject*> scope(aCx, JS::CurrentGlobalOrNull(aCx));
return XPCOMObjectToJsval(aCx, scope, helper, nullptr, true, aValue);
}
// Accept nsRefPtr/nsCOMPtr
template <typename T>
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
const nsCOMPtr<T>& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
return ToJSValue(aCx, *aArgument.get(), aValue);
}
template <typename T>
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
const RefPtr<T>& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
return ToJSValue(aCx, *aArgument.get(), aValue);
}
template <typename T>
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
const NonNull<T>& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
return ToJSValue(aCx, *aArgument.get(), aValue);
}
// Accept WebIDL dictionaries
template <class T>
MOZ_MUST_USE
typename EnableIf<IsBaseOf<DictionaryBase, T>::value, bool>::Type
ToJSValue(JSContext* aCx,
const T& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
return aArgument.ToObjectInternal(aCx, aValue);
}
// Accept existing JS values (which may not be same-compartment with us
MOZ_MUST_USE inline bool
ToJSValue(JSContext* aCx, const JS::Value& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
aValue.set(aArgument);
return MaybeWrapValue(aCx, aValue);
}
MOZ_MUST_USE inline bool
ToJSValue(JSContext* aCx, JS::Handle<JS::Value> aArgument,
JS::MutableHandle<JS::Value> aValue)
{
aValue.set(aArgument);
return MaybeWrapValue(aCx, aValue);
}
// Accept existing JS values on the Heap (which may not be same-compartment with us
MOZ_MUST_USE inline bool
ToJSValue(JSContext* aCx, const JS::Heap<JS::Value>& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
aValue.set(aArgument);
return MaybeWrapValue(aCx, aValue);
}
// Accept existing rooted JS values (which may not be same-compartment with us
MOZ_MUST_USE inline bool
ToJSValue(JSContext* aCx, const JS::Rooted<JS::Value>& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
aValue.set(aArgument);
return MaybeWrapValue(aCx, aValue);
}
// Accept existing rooted JS objects (which may not be same-compartment with
// us).
MOZ_MUST_USE inline bool
ToJSValue(JSContext* aCx, const JS::Rooted<JSObject*>& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
aValue.setObjectOrNull(aArgument);
return MaybeWrapObjectOrNullValue(aCx, aValue);
}
// Accept nsresult, for use in rejections, and create an XPCOM
// exception object representing that nsresult.
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
nsresult aArgument,
JS::MutableHandle<JS::Value> aValue);
// Accept ErrorResult, for use in rejections, and create an exception
// representing the failure. Note, the ErrorResult must indicate a failure
// with aArgument.Failure() returning true.
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
ErrorResult& aArgument,
JS::MutableHandle<JS::Value> aValue);
// Accept owning WebIDL unions.
template <typename T>
MOZ_MUST_USE
typename EnableIf<IsBaseOf<AllOwningUnionBase, T>::value, bool>::Type
ToJSValue(JSContext* aCx,
const T& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
JS::Rooted<JSObject*> global(aCx, JS::CurrentGlobalOrNull(aCx));
return aArgument.ToJSVal(aCx, global, aValue);
}
// Accept pointers to other things we accept
template <typename T>
MOZ_MUST_USE
typename EnableIf<IsPointer<T>::value, bool>::Type
ToJSValue(JSContext* aCx,
T aArgument,
JS::MutableHandle<JS::Value> aValue)
{
return ToJSValue(aCx, *aArgument, aValue);
}
// Accept Promise objects, which need special handling.
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
Promise& aArgument,
JS::MutableHandle<JS::Value> aValue);
// Accept arrays (and nested arrays) of other things we accept
template <typename T>
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
T* aArguments,
size_t aLength,
JS::MutableHandle<JS::Value> aValue);
template <typename T>
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
const nsTArray<T>& aArgument,
JS::MutableHandle<JS::Value> aValue)
{
return ToJSValue(aCx, aArgument.Elements(),
aArgument.Length(), aValue);
}
template <typename T>
MOZ_MUST_USE 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>
MOZ_MUST_USE bool
ToJSValue(JSContext* aCx,
const T(&aArgument)[N],
JS::MutableHandle<JS::Value> aValue)
{
return ToJSValue(aCx, aArgument, N, aValue);
}
// Accept arrays of other things we accept
template <typename T>
MOZ_MUST_USE 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[i])) {
return false;
}
}
JSObject* arrayObj = JS_NewArrayObject(aCx, v);
if (!arrayObj) {
return false;
}
aValue.setObject(*arrayObj);
return true;
}
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_ToJSValue_h */