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/* 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_StreamUtils_h
#define mozilla_dom_StreamUtils_h
#include "mozilla/ErrorResult.h"
#include "mozilla/dom/Promise.h"
class nsIGlobalObject;
namespace mozilla::dom {
struct QueuingStrategy;
double ExtractHighWaterMark(const QueuingStrategy& aStrategy,
double aDefaultHWM, ErrorResult& aRv);
// Promisification algorithm, shared among:
// Step 2 and 3 of https://streams.spec.whatwg.org/#readablestream-set-up
// Step 2 and 3 of
// https://streams.spec.whatwg.org/#readablestream-set-up-with-byte-reading-support
// Step 2 and 3 of https://streams.spec.whatwg.org/#writablestream-set-up
// Step 5 and 6 of https://streams.spec.whatwg.org/#transformstream-set-up
template <typename T>
MOZ_CAN_RUN_SCRIPT static already_AddRefed<Promise> PromisifyAlgorithm(
nsIGlobalObject* aGlobal, T aFunc, mozilla::ErrorResult& aRv) {
// Step 1. Let result be the result of running (algorithm). If this throws an
// exception e, return a promise rejected with e.
RefPtr<Promise> result;
if constexpr (!std::is_same<decltype(aFunc(aRv)), void>::value) {
result = aFunc(aRv);
} else {
aFunc(aRv);
}
if (aRv.IsUncatchableException()) {
return nullptr;
}
if (aRv.Failed()) {
return Promise::CreateRejectedWithErrorResult(aGlobal, aRv);
}
// Step 2. If result is a Promise, then return result.
if (result) {
return result.forget();
}
// Step 3. Return a promise resolved with undefined.
return Promise::CreateResolvedWithUndefined(aGlobal, aRv);
}
} // namespace mozilla::dom
#endif // mozilla_dom_StreamUtils_h
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