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/* -*- 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,
#ifndef mozilla_dom_Promise_inl_h
#define mozilla_dom_Promise_inl_h
#include <type_traits>
#include <utility>
#include "mozilla/AlreadyAddRefed.h"
#include "mozilla/ResultExtensions.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/dom/Promise.h"
#include "mozilla/dom/PromiseNativeHandler.h"
#include "nsCycleCollectionParticipant.h"
namespace mozilla::dom {
class PromiseNativeThenHandlerBase : public PromiseNativeHandler {
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(PromiseNativeThenHandlerBase)
PromiseNativeThenHandlerBase(Promise* aPromise) : mPromise(aPromise) {}
virtual bool HasResolvedCallback() = 0;
virtual bool HasRejectedCallback() = 0;
MOZ_CAN_RUN_SCRIPT void ResolvedCallback(JSContext* aCx,
JS::Handle<JS::Value> aValue,
ErrorResult& aRv) override;
MOZ_CAN_RUN_SCRIPT void RejectedCallback(JSContext* aCx,
JS::Handle<JS::Value> aValue,
ErrorResult& aRv) override;
protected:
virtual ~PromiseNativeThenHandlerBase() = default;
MOZ_CAN_RUN_SCRIPT virtual already_AddRefed<Promise> CallResolveCallback(
JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv) = 0;
MOZ_CAN_RUN_SCRIPT virtual already_AddRefed<Promise> CallRejectCallback(
JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv) = 0;
virtual void Traverse(nsCycleCollectionTraversalCallback&) = 0;
virtual void Unlink() = 0;
virtual void Trace(const TraceCallbacks& aCallbacks, void* aClosure) = 0;
RefPtr<Promise> mPromise;
};
namespace {
template <typename T, bool = IsRefcounted<std::remove_pointer_t<T>>::value,
bool = (std::is_convertible_v<T, nsISupports*> ||
std::is_convertible_v<T*, nsISupports*>)>
struct StorageTypeHelper {
using Type = T;
};
template <typename T>
struct StorageTypeHelper<T, true, true> {
using Type = nsCOMPtr<T>;
};
template <typename T>
struct StorageTypeHelper<nsCOMPtr<T>, true, true> {
using Type = nsCOMPtr<T>;
};
template <typename T>
struct StorageTypeHelper<T*, true, false> {
using Type = RefPtr<T>;
};
template <typename T>
struct StorageTypeHelper<JS::Handle<T>, false, false> {
using Type = JS::Heap<T>;
};
template <template <typename> class SmartPtr, typename T>
struct StorageTypeHelper<SmartPtr<T>, true, false>
: std::enable_if<std::is_convertible_v<SmartPtr<T>, T*>, RefPtr<T>> {
using Type = typename StorageTypeHelper::enable_if::type;
};
template <typename T>
using StorageType = typename StorageTypeHelper<std::decay_t<T>>::Type;
// Helpers to choose the correct argument type based on the storage type. Smart
// pointers are converted to the corresponding raw pointer type. Everything else
// is passed by move reference.
//
// Note: We can't just use std::forward for this because the input type may be a
// raw pointer which does not match the argument type, and while the
// spec-compliant behavior there should still give us the expected results, MSVC
// considers it an illegal use of std::forward.
template <template <typename> class SmartPtr, typename T>
decltype(std::declval<SmartPtr<T>>().get()) ArgType(SmartPtr<T>& aVal) {
return aVal.get();
}
template <typename T>
T&& ArgType(T& aVal) {
return std::move(aVal);
}
using ::ImplCycleCollectionUnlink;
template <typename ResolveCallback, typename RejectCallback, typename ArgsTuple,
typename JSArgsTuple>
class NativeThenHandler;
template <typename ResolveCallback, typename RejectCallback, typename... Args,
typename... JSArgs>
class NativeThenHandler<ResolveCallback, RejectCallback, std::tuple<Args...>,
std::tuple<JSArgs...>>
final : public PromiseNativeThenHandlerBase {
public:
/**
* @param aPromise A promise that will be settled by the result of the
* callbacks. Any thrown value to ErrorResult passed to those callbacks will
* be used to reject the promise, otherwise the promise will be resolved with
* the return value.
* @param aOnResolve A resolve callback
* @param aOnReject A reject callback
* @param aArgs The custom arguments to be passed to the both callbacks. The
* handler class will grab them to make them live long enough and to allow
* cycle collection.
* @param aJSArgs The JS arguments to be passed to the both callbacks, after
* native arguments. The handler will also grab them and allow garbage
* collection.
*
* XXX(krosylight): ideally there should be two signatures, with or without a
* promise parameter. Unfortunately doing so confuses the compiler and errors
* out, because nothing prevents promise from being ResolveCallback.
*/
NativeThenHandler(Promise* aPromise, Maybe<ResolveCallback>&& aOnResolve,
Maybe<RejectCallback>&& aOnReject,
std::tuple<std::remove_reference_t<Args>...>&& aArgs,
std::tuple<std::remove_reference_t<JSArgs>...>&& aJSArgs)
: PromiseNativeThenHandlerBase(aPromise),
mOnResolve(std::forward<Maybe<ResolveCallback>>(aOnResolve)),
mOnReject(std::forward<Maybe<RejectCallback>>(aOnReject)),
mArgs(std::forward<decltype(aArgs)>(aArgs)),
mJSArgs(std::forward<decltype(aJSArgs)>(aJSArgs)) {
if constexpr (std::tuple_size<decltype(mJSArgs)>::value > 0) {
mozilla::HoldJSObjects(this);
}
}
protected:
~NativeThenHandler() override {
if constexpr (std::tuple_size<decltype(mJSArgs)>::value > 0) {
mozilla::DropJSObjects(this);
}
}
void Traverse(nsCycleCollectionTraversalCallback& cb) override {
auto* tmp = this;
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mArgs)
}
void Unlink() override {
auto* tmp = this;
NS_IMPL_CYCLE_COLLECTION_UNLINK(mArgs)
NS_IMPL_CYCLE_COLLECTION_UNLINK(mJSArgs)
}
void Trace(const TraceCallbacks& aCallbacks, void* aClosure) override {
std::apply(
[&aCallbacks, aClosure](auto&&... aArgs) {
(aCallbacks.Trace(&aArgs, "mJSArgs[]", aClosure), ...);
},
mJSArgs);
}
bool HasResolvedCallback() override { return mOnResolve.isSome(); }
bool HasRejectedCallback() override { return mOnReject.isSome(); }
MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> CallResolveCallback(
JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv) override {
return CallCallback(aCx, *mOnResolve, aValue, aRv);
}
MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> CallRejectCallback(
JSContext* aCx, JS::Handle<JS::Value> aValue, ErrorResult& aRv) override {
return CallCallback(aCx, *mOnReject, aValue, aRv);
}
// mJSArgs are marked with Trace() above, so they can be safely converted to
// Handles. But we should not circumvent the read barrier, so call
// exposeToActiveJS explicitly.
template <typename T>
static JS::Handle<T> GetJSArgHandleForCall(JS::Heap<T>& aArg) {
aArg.exposeToActiveJS();
return JS::Handle<T>::fromMarkedLocation(aArg.address());
}
template <typename TCallback, size_t... Indices, size_t... JSIndices>
MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> CallCallback(
JSContext* aCx, const TCallback& aHandler, JS::Handle<JS::Value> aValue,
ErrorResult& aRv, std::index_sequence<Indices...>,
std::index_sequence<JSIndices...>) {
return aHandler(aCx, aValue, aRv, ArgType(std::get<Indices>(mArgs))...,
GetJSArgHandleForCall(std::get<JSIndices>(mJSArgs))...);
}
template <typename TCallback>
MOZ_CAN_RUN_SCRIPT already_AddRefed<Promise> CallCallback(
JSContext* aCx, const TCallback& aHandler, JS::Handle<JS::Value> aValue,
ErrorResult& aRv) {
return CallCallback(aCx, aHandler, aValue, aRv,
std::index_sequence_for<Args...>{},
std::index_sequence_for<JSArgs...>{});
}
Maybe<ResolveCallback> mOnResolve;
Maybe<RejectCallback> mOnReject;
std::tuple<StorageType<Args>...> mArgs;
std::tuple<StorageType<JSArgs>...> mJSArgs;
};
} // anonymous namespace
template <typename ResolveCallback, typename RejectCallback, typename... Args,
typename... JSArgs>
Result<RefPtr<Promise>, nsresult>
Promise::ThenCatchWithCycleCollectedArgsJSImpl(
Maybe<ResolveCallback>&& aOnResolve, Maybe<RejectCallback>&& aOnReject,
std::tuple<Args...>&& aArgs, std::tuple<JSArgs...>&& aJSArgs) {
using HandlerType =
NativeThenHandler<ResolveCallback, RejectCallback, std::tuple<Args...>,
std::tuple<JSArgs...>>;
ErrorResult rv;
RefPtr<Promise> promise = Promise::Create(GetParentObject(), rv);
if (rv.Failed()) {
return Err(rv.StealNSResult());
}
auto* handler = new (fallible)
HandlerType(promise, std::forward<Maybe<ResolveCallback>>(aOnResolve),
std::forward<Maybe<RejectCallback>>(aOnReject),
std::forward<std::tuple<Args...>>(aArgs),
std::forward<std::tuple<JSArgs...>>(aJSArgs));
if (!handler) {
return Err(NS_ERROR_OUT_OF_MEMORY);
}
AppendNativeHandler(handler);
return std::move(promise);
}
template <typename ResolveCallback, typename RejectCallback, typename... Args>
Promise::ThenResult<ResolveCallback, Args...>
Promise::ThenCatchWithCycleCollectedArgsImpl(
Maybe<ResolveCallback>&& aOnResolve, Maybe<RejectCallback>&& aOnReject,
Args&&... aArgs) {
return ThenCatchWithCycleCollectedArgsJSImpl(
std::forward<Maybe<ResolveCallback>>(aOnResolve),
std::forward<Maybe<RejectCallback>>(aOnReject),
std::make_tuple(std::forward<Args>(aArgs)...), std::make_tuple());
}
template <typename ResolveCallback, typename RejectCallback, typename... Args>
Promise::ThenResult<ResolveCallback, Args...>
Promise::ThenCatchWithCycleCollectedArgs(ResolveCallback&& aOnResolve,
RejectCallback&& aOnReject,
Args&&... aArgs) {
return ThenCatchWithCycleCollectedArgsImpl(Some(aOnResolve), Some(aOnReject),
std::forward<Args>(aArgs)...);
}
template <typename Callback, typename... Args>
Promise::ThenResult<Callback, Args...> Promise::ThenWithCycleCollectedArgs(
Callback&& aOnResolve, Args&&... aArgs) {
return ThenCatchWithCycleCollectedArgsImpl(Some(aOnResolve),
Maybe<Callback>(Nothing()),
std::forward<Args>(aArgs)...);
}
template <typename Callback, typename... Args>
Promise::ThenResult<Callback, Args...> Promise::CatchWithCycleCollectedArgs(
Callback&& aOnReject, Args&&... aArgs) {
return ThenCatchWithCycleCollectedArgsImpl(Maybe<Callback>(Nothing()),
Some(aOnReject),
std::forward<Args>(aArgs)...);
}
template <typename ResolveCallback, typename RejectCallback, typename ArgsTuple,
typename JSArgsTuple>
Result<RefPtr<Promise>, nsresult> Promise::ThenCatchWithCycleCollectedArgsJS(
ResolveCallback&& aOnResolve, RejectCallback&& aOnReject, ArgsTuple&& aArgs,
JSArgsTuple&& aJSArgs) {
return ThenCatchWithCycleCollectedArgsJSImpl(
Some(aOnResolve), Some(aOnReject), std::forward<ArgsTuple>(aArgs),
std::forward<JSArgsTuple>(aJSArgs));
}
template <typename Callback, typename ArgsTuple, typename JSArgsTuple>
Result<RefPtr<Promise>, nsresult> Promise::ThenWithCycleCollectedArgsJS(
Callback&& aOnResolve, ArgsTuple&& aArgs, JSArgsTuple&& aJSArgs) {
return ThenCatchWithCycleCollectedArgsJSImpl(
Some(aOnResolve), Maybe<Callback>(Nothing()),
std::forward<ArgsTuple>(aArgs), std::forward<JSArgsTuple>(aJSArgs));
}
template <typename ResolveCallback, typename RejectCallback, typename... Args>
void Promise::AddCallbacksWithCycleCollectedArgs(ResolveCallback&& aOnResolve,
RejectCallback&& aOnReject,
Args&&... aArgs) {
auto onResolve =
[aOnResolve](JSContext* aCx, JS::Handle<JS::Value> value,
ErrorResult& aRv,
StorageType<Args>&&... aArgs) -> already_AddRefed<Promise> {
aOnResolve(aCx, value, aRv, aArgs...);
return nullptr;
};
auto onReject =
[aOnReject](JSContext* aCx, JS::Handle<JS::Value> value, ErrorResult& aRv,
StorageType<Args>&&... aArgs) -> already_AddRefed<Promise> {
aOnReject(aCx, value, aRv, aArgs...);
return nullptr;
};
// Note: explicit template parameters for clang<7/gcc<8 without "Template
// argument deduction for class templates" support
AppendNativeHandler(
new NativeThenHandler<decltype(onResolve), decltype(onReject),
std::tuple<Args...>, std::tuple<>>(
nullptr, Some(onResolve), Some(onReject),
std::make_tuple(std::forward<Args>(aArgs)...), std::make_tuple()));
}
} // namespace mozilla::dom
#endif // mozilla_dom_Promise_inl_h