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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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/. */
#include "nsThreadUtils.h"
#include "mozilla/dom/Promise.h"
#include "mozilla/dom/RootedDictionary.h"
#include "mozilla/uniffi/Call.h"
#include "mozilla/uniffi/ResultPromise.h"
namespace mozilla::uniffi {
extern mozilla::LazyLogModule gUniffiLogger;
using dom::GlobalObject;
using dom::OwningUniFFIScaffoldingValue;
using dom::RootedDictionary;
using dom::Sequence;
using dom::UniFFIScaffoldingCallResult;
void UniffiSyncCallHandler::CallSync(
UniquePtr<UniffiSyncCallHandler> aHandler, const GlobalObject& aGlobal,
const Sequence<OwningUniFFIScaffoldingValue>& aArgs,
RootedDictionary<UniFFIScaffoldingCallResult>& aReturnValue,
ErrorResult& aError) {
MOZ_ASSERT(NS_IsMainThread());
aHandler->LowerRustArgs(aArgs, aError);
if (aError.Failed()) {
return;
}
RustCallStatus callStatus{};
aHandler->MakeRustCall(&callStatus);
aHandler->mUniffiCallStatusCode = callStatus.code;
if (callStatus.error_buf.data) {
aHandler->mUniffiCallStatusErrorBuf =
FfiValueRustBuffer(callStatus.error_buf);
}
aHandler->LiftCallResult(aGlobal.Context(), aReturnValue, aError);
}
already_AddRefed<dom::Promise> UniffiSyncCallHandler::CallAsyncWrapper(
UniquePtr<UniffiSyncCallHandler> aHandler, const dom::GlobalObject& aGlobal,
const dom::Sequence<dom::OwningUniFFIScaffoldingValue>& aArgs,
ErrorResult& aError) {
MOZ_ASSERT(NS_IsMainThread());
aHandler->LowerRustArgs(aArgs, aError);
if (aError.Failed()) {
return nullptr;
}
uniffi::ResultPromise resultPromise;
resultPromise.Init(aGlobal, aError);
if (aError.Failed()) {
return nullptr;
}
nsresult dispatchResult = NS_DispatchBackgroundTask(
NS_NewRunnableFunction("UniffiSyncCallHandler::CallAsyncWrapper",
[handler = std::move(aHandler),
resultPromise = resultPromise]() mutable {
RustCallStatus callStatus{};
handler->MakeRustCall(&callStatus);
handler->mUniffiCallStatusCode = callStatus.code;
if (callStatus.error_buf.data) {
handler->mUniffiCallStatusErrorBuf =
FfiValueRustBuffer(callStatus.error_buf);
}
resultPromise.Complete(std::move(handler));
}),
NS_DISPATCH_EVENT_MAY_BLOCK);
if (NS_FAILED(dispatchResult)) {
MOZ_LOG(gUniffiLogger, LogLevel::Error,
("[UniFFI] NS_DispatchBackgroundTask failed"));
resultPromise.RejectWithUnexpectedError();
}
return do_AddRef(resultPromise.GetPromise());
}
void UniffiCallHandlerBase::LiftCallResult(
JSContext* aCx,
dom::RootedDictionary<dom::UniFFIScaffoldingCallResult>& aDest,
ErrorResult& aError) {
switch (mUniffiCallStatusCode) {
case RUST_CALL_SUCCESS: {
aDest.mCode = dom::UniFFIScaffoldingCallCode::Success;
LiftSuccessfulCallResult(aCx, aDest.mData, aError);
break;
}
case RUST_CALL_ERROR: {
// Rust Err() value. Populate data with the `RustBuffer` containing the
// error
aDest.mCode = dom::UniFFIScaffoldingCallCode::Error;
mUniffiCallStatusErrorBuf.Lift(aCx, &aDest.mData.Construct(), aError);
break;
}
default: {
// This indicates a RustError, which should rarely happen in practice.
// The normal case is a Rust panic, but FF sets panic=abort.
aDest.mCode = dom::UniFFIScaffoldingCallCode::Internal_error;
if (mUniffiCallStatusErrorBuf.IsSet()) {
mUniffiCallStatusErrorBuf.Lift(aCx, &aDest.mData.Construct(), aError);
}
break;
}
}
}
already_AddRefed<dom::Promise> UniffiAsyncCallHandler::CallAsync(
UniquePtr<UniffiAsyncCallHandler> aHandler,
const dom::GlobalObject& aGlobal,
const dom::Sequence<dom::OwningUniFFIScaffoldingValue>& aArgs,
ErrorResult& aError) {
MOZ_ASSERT(NS_IsMainThread());
// Async calls return a Future rather than doing any work. This means we can
// make the call right now on the JS main thread without fear of blocking it.
aHandler->LowerArgsAndMakeRustCall(aArgs, aError);
if (aError.Failed()) {
return nullptr;
}
aHandler->mPromise.Init(aGlobal, aError);
if (aError.Failed()) {
return nullptr;
}
ResultPromise returnPromise(aHandler->mPromise);
// Schedule a poll for the future in a background thread.
nsresult dispatchResult = NS_DispatchBackgroundTask(
NS_NewRunnableFunction("UniffiAsyncCallHandler::CallAsync",
[handler = std::move(aHandler)]() mutable {
UniffiAsyncCallHandler::Poll(std::move(handler));
}));
if (NS_FAILED(dispatchResult)) {
MOZ_LOG(gUniffiLogger, LogLevel::Error,
("[UniFFI] NS_DispatchBackgroundTask failed"));
aHandler->mPromise.RejectWithUnexpectedError();
}
return do_AddRef(returnPromise.GetPromise());
}
// Callback function for async calls
//
// This is passed to Rust when we poll the future alongside a 64-bit handle that
// represents the callback data. For uniffi-bindgen-gecko-js, the handle is a
// `UniffiAsyncCallHandler*` casted to an int.
//
// Rust calls this when either the future is ready or when it's time to poll it
// again.
void UniffiAsyncCallHandler::FutureCallback(uint64_t aCallHandlerHandle,
int8_t aCode) {
// Recreate the UniquePtr we previously released
UniquePtr<UniffiAsyncCallHandler> handler(
reinterpret_cast<UniffiAsyncCallHandler*>(
static_cast<uintptr_t>(aCallHandlerHandle)));
switch (aCode) {
case UNIFFI_FUTURE_READY: {
// `Future::poll` returned a `Ready` value on the Rust side.
// Complete the future
RustCallStatus callStatus{};
handler->CallCompleteFn(&callStatus);
handler->mUniffiCallStatusCode = callStatus.code;
if (callStatus.error_buf.data) {
handler->mUniffiCallStatusErrorBuf =
FfiValueRustBuffer(callStatus.error_buf);
}
// Copy of the ResultPromise before moving the handler that contains it.
ResultPromise promise(handler->mPromise);
promise.Complete(std::move(handler));
break;
}
case UNIFFI_FUTURE_MAYBE_READY: {
// The Rust waker was invoked after `poll` returned a `Pending` value.
// Poll the future again soon in a background task.
nsresult dispatchResult =
NS_DispatchBackgroundTask(NS_NewRunnableFunction(
"UniffiAsyncCallHandler::FutureCallback",
[handler = std::move(handler)]() mutable {
UniffiAsyncCallHandler::Poll(std::move(handler));
}));
if (NS_FAILED(dispatchResult)) {
MOZ_LOG(gUniffiLogger, LogLevel::Error,
("[UniFFI] NS_DispatchBackgroundTask failed"));
handler->mPromise.RejectWithUnexpectedError();
}
break;
}
default: {
// Invalid poll code, this should never happen, but if it does log an
// error and reject the promise.
MOZ_LOG(gUniffiLogger, LogLevel::Error,
("[UniFFI] Invalid poll code in "
"UniffiAsyncCallHandler::FutureCallback %d",
aCode));
handler->mPromise.RejectWithUnexpectedError();
break;
}
};
}
void UniffiAsyncCallHandler::Poll(UniquePtr<UniffiAsyncCallHandler> aHandler) {
auto futureHandle = aHandler->mFutureHandle;
auto pollFn = aHandler->mPollFn;
// Release the UniquePtr into a raw pointer and convert it to a handle
// so that we can pass it as a handle to the UniFFI code. It gets converted
// back in `UniffiAsyncCallHandler::FutureCallback()`, which the Rust code
// guarentees will be called if the future makes progress.
uint64_t selfHandle =
static_cast<uint64_t>(reinterpret_cast<uintptr_t>(aHandler.release()));
pollFn(futureHandle, UniffiAsyncCallHandler::FutureCallback, selfHandle);
}
UniffiAsyncCallHandler::~UniffiAsyncCallHandler() { mFreeFn(mFutureHandle); }
} // namespace mozilla::uniffi
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