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ladybird/Userland/Libraries/LibJS/Runtime/Promise.cpp

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LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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/*
Everywhere: Use linusg@serenityos.org for my copyright headers
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* Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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*
Everything: Move to SPDX license identifiers in all files. SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
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* SPDX-License-Identifier: BSD-2-Clause
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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*/
#include <AK/Debug.h>
#include <AK/Function.h>
#include <AK/Optional.h>
LibJS: Remove unused includes out of Cell.h, move to the users Almost everything in LibJS includes Cell.h, don't force all code to include AK/TypeCasts.h + AK/String.h. Instead include them where they are actually used and required.
2021-07-31 07:43:42 +00:00
#include <AK/TypeCasts.h>
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/JobCallback.h>
#include <LibJS/Runtime/Promise.h>
#include <LibJS/Runtime/PromiseJobs.h>
#include <LibJS/Runtime/PromiseReaction.h>
#include <LibJS/Runtime/PromiseResolvingFunction.h>
namespace JS {
LibJS: Add ECMA-262 section/title/URL comments almost everywhere As mentioned on Discord earlier, we'll add these to all new functions going forward - this is the backfill. Reasons: - It makes you look at the spec, implementing based on MDN or V8 behavior is a no-go - It makes finding the various functions that are non-compliant easier, in the future everything should either have such a comment or, if it's not from the spec at all, a comment explaining why that is the case - It makes it easier to check whether a certain abstract operation is implemented in LibJS, not all of them use the same name as the spec. E.g. RejectPromise() is Promise::reject() - It makes it easier to reason about vm.arguments(), e.g. when the function has a rest parameter - It makes it easier to see whether a certain function is from a proposal or Annex B Also: - Add arguments to all functions and abstract operations that already had a comment - Fix some outdated section numbers - Replace some ecma-international.org URLs with tc39.es
2021-06-12 23:22:35 +00:00
// 27.2.4.7.1 PromiseResolve ( C, x ), https://tc39.es/ecma262/#sec-promise-resolve
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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Object* promise_resolve(GlobalObject& global_object, Object& constructor, Value value)
{
auto& vm = global_object.vm();
if (value.is_object() && is<Promise>(value.as_object())) {
LibJS: Remove unnecessary value_or() from get() Object::get() never returns an empty value anymore, as per the spec, so having a value_or() fallback is no longer needed.
2021-07-04 21:55:45 +00:00
auto value_constructor = value.as_object().get(vm.names.constructor);
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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if (vm.exception())
return nullptr;
if (same_value(value_constructor, &constructor))
return &static_cast<Promise&>(value.as_object());
}
auto promise_capability = new_promise_capability(global_object, &constructor);
if (vm.exception())
return nullptr;
[[maybe_unused]] auto result = vm.call(*promise_capability.resolve, js_undefined(), value);
if (vm.exception())
return nullptr;
return promise_capability.promise;
}
Promise* Promise::create(GlobalObject& global_object)
{
return global_object.heap().allocate<Promise>(global_object, *global_object.promise_prototype());
}
Promise::Promise(Object& prototype)
: Object(prototype)
{
}
LibJS: Add ECMA-262 section/title/URL comments almost everywhere As mentioned on Discord earlier, we'll add these to all new functions going forward - this is the backfill. Reasons: - It makes you look at the spec, implementing based on MDN or V8 behavior is a no-go - It makes finding the various functions that are non-compliant easier, in the future everything should either have such a comment or, if it's not from the spec at all, a comment explaining why that is the case - It makes it easier to check whether a certain abstract operation is implemented in LibJS, not all of them use the same name as the spec. E.g. RejectPromise() is Promise::reject() - It makes it easier to reason about vm.arguments(), e.g. when the function has a rest parameter - It makes it easier to see whether a certain function is from a proposal or Annex B Also: - Add arguments to all functions and abstract operations that already had a comment - Fix some outdated section numbers - Replace some ecma-international.org URLs with tc39.es
2021-06-12 23:22:35 +00:00
// 27.2.1.3 CreateResolvingFunctions ( promise ), https://tc39.es/ecma262/#sec-createresolvingfunctions
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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Promise::ResolvingFunctions Promise::create_resolving_functions()
{
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / create_resolving_functions()]", this);
auto& vm = this->vm();
auto* already_resolved = vm.heap().allocate_without_global_object<AlreadyResolved>();
// 27.2.1.3.2 Promise Resolve Functions, https://tc39.es/ecma262/#sec-promise-resolve-functions
auto* resolve_function = PromiseResolvingFunction::create(global_object(), *this, *already_resolved, [](auto& vm, auto& global_object, auto& promise, auto& already_resolved) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Resolve function was called", &promise);
if (already_resolved.value) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Promise is already resolved, returning undefined", &promise);
return js_undefined();
}
already_resolved.value = true;
LibJS: Remove two unnecessary 'vm.argument(0).value_or(js_undefined())' VM::argument() never returns an empty value.
2021-07-04 21:51:50 +00:00
auto resolution = vm.argument(0);
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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if (resolution.is_object() && &resolution.as_object() == &promise) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Promise can't be resolved with itself, rejecting with error", &promise);
auto* self_resolution_error = TypeError::create(global_object, "Cannot resolve promise with itself");
return promise.reject(self_resolution_error);
}
if (!resolution.is_object()) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Resolution is not an object, fulfilling with {}", &promise, resolution);
return promise.fulfill(resolution);
}
auto then_action = resolution.as_object().get(vm.names.then);
if (vm.exception()) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Exception while getting 'then' property, rejecting with error", &promise);
auto error = vm.exception()->value();
vm.clear_exception();
vm.stop_unwind();
return promise.reject(error);
}
if (!then_action.is_function()) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Then action is not a function, fulfilling with {}", &promise, resolution);
return promise.fulfill(resolution);
}
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Creating JobCallback for then action @ {}", &promise, &then_action.as_function());
auto then_job_callback = make_job_callback(then_action.as_function());
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Creating PromiseResolveThenableJob for thenable {}", &promise, resolution);
auto* job = PromiseResolveThenableJob::create(global_object, promise, resolution, then_job_callback);
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Enqueuing job @ {}", &promise, job);
vm.enqueue_promise_job(*job);
return js_undefined();
});
LibJS: Reorder and add missing name & length properties to Built-ins The specification dicatates that each built-in will have a length and name property. (defined in that order)
2021-07-07 23:49:53 +00:00
resolve_function->define_direct_property(vm.names.name, js_string(vm, vm.names.resolve.as_string()), Attribute::Configurable);
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
2021-04-01 20:13:29 +00:00
// 27.2.1.3.1 Promise Reject Functions, https://tc39.es/ecma262/#sec-promise-reject-functions
auto* reject_function = PromiseResolvingFunction::create(global_object(), *this, *already_resolved, [](auto& vm, auto&, auto& promise, auto& already_resolved) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / PromiseResolvingFunction]: Reject function was called", &promise);
if (already_resolved.value)
return js_undefined();
already_resolved.value = true;
LibJS: Remove two unnecessary 'vm.argument(0).value_or(js_undefined())' VM::argument() never returns an empty value.
2021-07-04 21:51:50 +00:00
auto reason = vm.argument(0);
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
2021-04-01 20:13:29 +00:00
return promise.reject(reason);
});
LibJS: Reorder and add missing name & length properties to Built-ins The specification dicatates that each built-in will have a length and name property. (defined in that order)
2021-07-07 23:49:53 +00:00
reject_function->define_direct_property(vm.names.name, js_string(vm, vm.names.reject.as_string()), Attribute::Configurable);
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
2021-04-01 20:13:29 +00:00
return { *resolve_function, *reject_function };
}
LibJS: Add ECMA-262 section/title/URL comments almost everywhere As mentioned on Discord earlier, we'll add these to all new functions going forward - this is the backfill. Reasons: - It makes you look at the spec, implementing based on MDN or V8 behavior is a no-go - It makes finding the various functions that are non-compliant easier, in the future everything should either have such a comment or, if it's not from the spec at all, a comment explaining why that is the case - It makes it easier to check whether a certain abstract operation is implemented in LibJS, not all of them use the same name as the spec. E.g. RejectPromise() is Promise::reject() - It makes it easier to reason about vm.arguments(), e.g. when the function has a rest parameter - It makes it easier to see whether a certain function is from a proposal or Annex B Also: - Add arguments to all functions and abstract operations that already had a comment - Fix some outdated section numbers - Replace some ecma-international.org URLs with tc39.es
2021-06-12 23:22:35 +00:00
// 27.2.1.4 FulfillPromise ( promise, value ), https://tc39.es/ecma262/#sec-fulfillpromise
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
2021-04-01 20:13:29 +00:00
Value Promise::fulfill(Value value)
{
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / fulfill()]: Fulfilling promise with value {}", this, value);
VERIFY(m_state == State::Pending);
VERIFY(!value.is_empty());
m_state = State::Fulfilled;
m_result = value;
trigger_reactions();
m_fulfill_reactions.clear();
m_reject_reactions.clear();
return js_undefined();
}
LibJS: Add ECMA-262 section/title/URL comments almost everywhere As mentioned on Discord earlier, we'll add these to all new functions going forward - this is the backfill. Reasons: - It makes you look at the spec, implementing based on MDN or V8 behavior is a no-go - It makes finding the various functions that are non-compliant easier, in the future everything should either have such a comment or, if it's not from the spec at all, a comment explaining why that is the case - It makes it easier to check whether a certain abstract operation is implemented in LibJS, not all of them use the same name as the spec. E.g. RejectPromise() is Promise::reject() - It makes it easier to reason about vm.arguments(), e.g. when the function has a rest parameter - It makes it easier to see whether a certain function is from a proposal or Annex B Also: - Add arguments to all functions and abstract operations that already had a comment - Fix some outdated section numbers - Replace some ecma-international.org URLs with tc39.es
2021-06-12 23:22:35 +00:00
// 27.2.1.7 RejectPromise ( promise, reason ), https://tc39.es/ecma262/#sec-rejectpromise
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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Value Promise::reject(Value reason)
{
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / reject()]: Rejecting promise with reason {}", this, reason);
VERIFY(m_state == State::Pending);
VERIFY(!reason.is_empty());
auto& vm = this->vm();
m_state = State::Rejected;
m_result = reason;
if (!m_is_handled)
vm.promise_rejection_tracker(*this, RejectionOperation::Reject);
trigger_reactions();
m_fulfill_reactions.clear();
m_reject_reactions.clear();
return js_undefined();
}
LibJS: Add ECMA-262 section/title/URL comments almost everywhere As mentioned on Discord earlier, we'll add these to all new functions going forward - this is the backfill. Reasons: - It makes you look at the spec, implementing based on MDN or V8 behavior is a no-go - It makes finding the various functions that are non-compliant easier, in the future everything should either have such a comment or, if it's not from the spec at all, a comment explaining why that is the case - It makes it easier to check whether a certain abstract operation is implemented in LibJS, not all of them use the same name as the spec. E.g. RejectPromise() is Promise::reject() - It makes it easier to reason about vm.arguments(), e.g. when the function has a rest parameter - It makes it easier to see whether a certain function is from a proposal or Annex B Also: - Add arguments to all functions and abstract operations that already had a comment - Fix some outdated section numbers - Replace some ecma-international.org URLs with tc39.es
2021-06-12 23:22:35 +00:00
// 27.2.1.8 TriggerPromiseReactions ( reactions, argument ), https://tc39.es/ecma262/#sec-triggerpromisereactions
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
2021-04-01 20:13:29 +00:00
void Promise::trigger_reactions() const
{
VERIFY(is_settled());
auto& vm = this->vm();
auto& reactions = m_state == State::Fulfilled
? m_fulfill_reactions
: m_reject_reactions;
for (auto& reaction : reactions) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / trigger_reactions()]: Creating PromiseReactionJob for PromiseReaction @ {} with argument {}", this, &reaction, m_result);
auto* job = PromiseReactionJob::create(global_object(), *reaction, m_result);
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / trigger_reactions()]: Enqueuing job @ {}", this, job);
vm.enqueue_promise_job(*job);
}
if constexpr (PROMISE_DEBUG) {
if (reactions.is_empty())
dbgln("[Promise @ {} / trigger_reactions()]: No reactions!", this);
}
}
LibJS: Add ECMA-262 section/title/URL comments almost everywhere As mentioned on Discord earlier, we'll add these to all new functions going forward - this is the backfill. Reasons: - It makes you look at the spec, implementing based on MDN or V8 behavior is a no-go - It makes finding the various functions that are non-compliant easier, in the future everything should either have such a comment or, if it's not from the spec at all, a comment explaining why that is the case - It makes it easier to check whether a certain abstract operation is implemented in LibJS, not all of them use the same name as the spec. E.g. RejectPromise() is Promise::reject() - It makes it easier to reason about vm.arguments(), e.g. when the function has a rest parameter - It makes it easier to see whether a certain function is from a proposal or Annex B Also: - Add arguments to all functions and abstract operations that already had a comment - Fix some outdated section numbers - Replace some ecma-international.org URLs with tc39.es
2021-06-12 23:22:35 +00:00
// 27.2.5.4.1 PerformPromiseThen ( promise, onFulfilled, onRejected [ , resultCapability ] ), https://tc39.es/ecma262/#sec-performpromisethen
LibJS: Add initial support for Promises Almost a year after first working on this, it's finally done: an implementation of Promises for LibJS! :^) The core functionality is working and closely following the spec [1]. I mostly took the pseudo code and transformed it into C++ - if you read and understand it, you will know how the spec implements Promises; and if you read the spec first, the code will look very familiar. Implemented functions are: - Promise() constructor - Promise.prototype.then() - Promise.prototype.catch() - Promise.prototype.finally() - Promise.resolve() - Promise.reject() For the tests I added a new function to test-js's global object, runQueuedPromiseJobs(), which calls vm.run_queued_promise_jobs(). By design, queued jobs normally only run after the script was fully executed, making it improssible to test handlers in individual test() calls by default [2]. Subsequent commits include integrations into LibWeb and js(1) - pretty-printing, running queued promise jobs when necessary. This has an unusual amount of dbgln() statements, all hidden behind the PROMISE_DEBUG flag - I'm leaving them in for now as they've been very useful while debugging this, things can get quite complex with so many asynchronously executed functions. I've not extensively explored use of these APIs for promise-based functionality in LibWeb (fetch(), Notification.requestPermission() etc.), but we'll get there in due time. [1]: https://tc39.es/ecma262/#sec-promise-objects [2]: https://tc39.es/ecma262/#sec-jobs-and-job-queues
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Value Promise::perform_then(Value on_fulfilled, Value on_rejected, Optional<PromiseCapability> result_capability)
{
auto& vm = this->vm();
Optional<JobCallback> on_fulfilled_job_callback;
if (on_fulfilled.is_function()) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: Creating JobCallback for on_fulfilled function @ {}", this, &on_fulfilled.as_function());
on_fulfilled_job_callback = make_job_callback(on_fulfilled.as_function());
}
Optional<JobCallback> on_rejected_job_callback;
if (on_rejected.is_function()) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: Creating JobCallback for on_rejected function @ {}", this, &on_rejected.as_function());
on_rejected_job_callback = make_job_callback(on_rejected.as_function());
}
auto* fulfill_reaction = PromiseReaction::create(vm, PromiseReaction::Type::Fulfill, result_capability, on_fulfilled_job_callback);
auto* reject_reaction = PromiseReaction::create(vm, PromiseReaction::Type::Reject, result_capability, on_rejected_job_callback);
switch (m_state) {
case Promise::State::Pending:
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: state is State::Pending, adding fulfill/reject reactions", this);
m_fulfill_reactions.append(fulfill_reaction);
m_reject_reactions.append(reject_reaction);
break;
case Promise::State::Fulfilled: {
auto value = m_result;
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: State is State::Fulfilled, creating PromiseReactionJob for PromiseReaction @ {} with argument {}", this, fulfill_reaction, value);
auto* fulfill_job = PromiseReactionJob::create(global_object(), *fulfill_reaction, value);
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: Enqueuing job @ {}", this, fulfill_job);
vm.enqueue_promise_job(*fulfill_job);
break;
}
case Promise::State::Rejected: {
auto reason = m_result;
if (!m_is_handled)
vm.promise_rejection_tracker(*this, RejectionOperation::Handle);
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: State is State::Rejected, creating PromiseReactionJob for PromiseReaction @ {} with argument {}", this, reject_reaction, reason);
auto* reject_job = PromiseReactionJob::create(global_object(), *reject_reaction, reason);
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: Enqueuing job @ {}", this, reject_job);
vm.enqueue_promise_job(*reject_job);
break;
}
default:
VERIFY_NOT_REACHED();
}
m_is_handled = true;
if (!result_capability.has_value()) {
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: No ResultCapability, returning undefined", this);
return js_undefined();
}
auto* promise = result_capability.value().promise;
dbgln_if(PROMISE_DEBUG, "[Promise @ {} / perform_then()]: Returning Promise @ {} from ResultCapability @ {}", this, promise, &result_capability.value());
return promise;
}
void Promise::visit_edges(Cell::Visitor& visitor)
{
Base::visit_edges(visitor);
visitor.visit(m_result);
for (auto& reaction : m_fulfill_reactions)
visitor.visit(reaction);
for (auto& reaction : m_reject_reactions)
visitor.visit(reaction);
}
}
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