Abstract closures, Promises, and such work

nova_vm/src/ecmascript/builtins/control_abstraction_objects/promise_objects.rs

@@ -1,2 +1,3 @@
+pub(crate) mod promise_abstract_operations;
 pub(crate) mod promise_constructor;
 pub(crate) mod promise_prototype;

nova_vm/src/ecmascript/builtins/control_abstraction_objects/promise_objects/promise_abstract_operations.rs

@@ -0,0 +1,280 @@
+use std::ops::{Index, IndexMut};
+
+use crate::{ecmascript::{abstract_operations::testing_and_comparison::is_constructor, builtins::{promise::Promise, ArgumentsList}, execution::{agent::ExceptionType, Agent, JsResult}, types::{AbstractClosureHeapData, Function, IntoValue, Object, String, Value}}, heap::{indexes::{BaseIndex, BoundFunctionIndex}, Heap}};
+
+use self::{promise_capability_records::PromiseCapability, promise_reaction_records::PromiseReaction};
+
+pub(crate) mod promise_capability_records;
+pub(crate) mod promise_reaction_records;
+
+pub(crate) struct PromiseResolvingFunctions {
+    pub(crate) resolve: Function,
+    pub(crate) reject: BuiltinPromiseRejectFunction,
+}
+
+/// ### [27.2.1.3 CreateResolvingFunctions ( promise )]()
+///
+/// The abstract operation CreateResolvingFunctions takes argument promise (a
+/// Promise) and returns a Record with fields \[\[Resolve\]\] (a function
+/// object) and \[\[Reject\]\] (a function object).
+pub(crate) fn create_resolving_functions(agent: &mut Agent, promise: Promise) -> PromiseResolvingFunctions {
+    // 1. Let alreadyResolved be the Record { [[Value]]: false }.
+    let already_resolved = false;
+    // 2. Let stepsResolve be the algorithm steps defined in Promise Resolve Functions.
+    // 3. Let lengthResolve be the number of non-optional parameters of the function definition in Promise Resolve Functions.
+    // 4. Let resolve be CreateBuiltinFunction(stepsResolve, lengthResolve, "", « [[Promise]], [[AlreadyResolved]] »).
+    // TODO
+    let resolve = Function::BoundFunction(BoundFunctionIndex::from_u32_index(0));
+    // 5. Set resolve.[[Promise]] to promise.
+    // 6. Set resolve.[[AlreadyResolved]] to alreadyResolved.
+    // 7. Let stepsReject be the algorithm steps defined in Promise Reject Functions.
+    // 8. Let lengthReject be the number of non-optional parameters of the function definition in Promise Reject Functions.
+    // 9. Let reject be CreateBuiltinFunction(stepsReject, lengthReject, "", « [[Promise]], [[AlreadyResolved]] »).
+    let reject = PromiseRejectFunctionHeapData {
+        promise,
+        already_resolved,
+        object_index: None,
+    };
+    // 10. Set reject.[[Promise]] to promise.
+    // 11. Set reject.[[AlreadyResolved]] to alreadyResolved.
+    agent.heap.promise_reject_functions.push(Some(reject));
+    let reject = BuiltinPromiseRejectFunction(BuiltinPromiseRejectFunctionIndex::last(&agent.heap.promise_reject_functions));
+    // 12. Return the Record { [[Resolve]]: resolve, [[Reject]]: reject }.
+    PromiseResolvingFunctions { resolve, reject }
+}
+
+/// ### [27.2.1.3.1 Promise Reject Functions]()
+///
+/// A promise reject function is an anonymous built-in function that has
+/// \[\[Promise\]\] and \[\[AlreadyResolved\]\] internal slots.
+/// 
+/// The "length" property of a promise reject function is 1𝔽.
+#[derive(Debug, Clone, Copy)]
+pub(crate) struct PromiseRejectFunctionHeapData {
+    /// \[\[Promise\]\]
+    pub(crate) promise: Promise,
+    /// \[\[AlreadyResolved\]\]
+    pub(crate) already_resolved: bool,
+    pub(crate) object_index: Option<Object>,
+}
+
+pub(crate) type BuiltinPromiseRejectFunctionIndex = BaseIndex<PromiseRejectFunctionHeapData>;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) struct BuiltinPromiseRejectFunction(pub(crate) BuiltinPromiseRejectFunctionIndex);
+
+impl Index<BuiltinPromiseRejectFunction> for Agent {
+    type Output = PromiseRejectFunctionHeapData;
+
+    fn index(&self, index: BuiltinPromiseRejectFunction) -> &Self::Output {
+        &self.heap[index]
+    }
+}
+
+impl IndexMut<BuiltinPromiseRejectFunction> for Agent {
+    fn index_mut(&mut self, index: BuiltinPromiseRejectFunction) -> &mut Self::Output {
+        &mut self.heap[index]
+    }
+}
+
+impl Index<BuiltinPromiseRejectFunction> for Heap {
+    type Output = PromiseRejectFunctionHeapData;
+
+    fn index(&self, index: BuiltinPromiseRejectFunction) -> &Self::Output {
+        self.promise_reject_functions
+            .get(index.0.into_index())
+            .expect("BuiltinPromiseRejectFunction out of bounds")
+            .as_ref()
+            .expect("BuiltinPromiseRejectFunction slot empty")
+    }
+}
+
+impl IndexMut<BuiltinPromiseRejectFunction> for Heap {
+    fn index_mut(&mut self, index: BuiltinPromiseRejectFunction) -> &mut Self::Output {
+        self.promise_reject_functions
+            .get_mut(index.0.into_index())
+            .expect("BuiltinPromiseRejectFunction out of bounds")
+            .as_mut()
+            .expect("BuiltinPromiseRejectFunction slot empty")
+    }
+}
+
+impl PromiseRejectFunctionHeapData {
+    /// When a promise reject function is called with argument reason, the
+    /// following steps are taken:
+    pub(crate) fn call(agent: &mut Agent, reason: Value) {
+        // 1. Let F be the active function object.
+        let f = agent.running_execution_context().function.unwrap();
+        // 2. Assert: F has a [[Promise]] internal slot whose value is an Object.
+        let Function::BuiltinPromiseRejectFunction(f) = f else {
+            unreachable!();
+        };
+        // 3. Let promise be F.[[Promise]].
+        // 4. Let alreadyResolved be F.[[AlreadyResolved]].
+        let PromiseRejectFunctionHeapData {
+            promise,
+            already_resolved,
+            ..
+        } = agent[BuiltinPromiseRejectFunction(f)];
+        // 5. If alreadyResolved.[[Value]] is true, return undefined.
+        if !already_resolved {
+            // 6. Set alreadyResolved.[[Value]] to true.
+            agent[BuiltinPromiseRejectFunction(f)].already_resolved = true;
+            // 7. Perform RejectPromise(promise, reason).
+            reject_promise(agent, promise, reason);
+            // 8. Return undefined.
+        }
+    }
+}
+
+
+/// ### [27.2.1.3.2 Promise Resolve Functions]()
+///
+/// A promise resolve function is an anonymous built-in function that has [[Promise]] and [[AlreadyResolved]] internal slots.
+
+// When a promise resolve function is called with argument resolution, the following steps are taken:
+
+// 1. Let F be the active function object.
+// 2. Assert: F has a [[Promise]] internal slot whose value is an Object.
+// 3. Let promise be F.[[Promise]].
+// 4. Let alreadyResolved be F.[[AlreadyResolved]].
+// 5. If alreadyResolved.[[Value]] is true, return undefined.
+// 6. Set alreadyResolved.[[Value]] to true.
+// 7. If SameValue(resolution, promise) is true, then
+// a. Let selfResolutionError be a newly created TypeError object.
+// b. Perform RejectPromise(promise, selfResolutionError).
+// c. Return undefined.
+// 8. If resolution is not an Object, then
+// a. Perform FulfillPromise(promise, resolution).
+// b. Return undefined.
+// 9. Let then be Completion(Get(resolution, "then")).
+// 10. If then is an abrupt completion, then
+// a. Perform RejectPromise(promise, then.[[Value]]).
+// b. Return undefined.
+// 11. Let thenAction be then.[[Value]].
+// 12. If IsCallable(thenAction) is false, then
+// a. Perform FulfillPromise(promise, resolution).
+// b. Return undefined.
+// 13. Let thenJobCallback be HostMakeJobCallback(thenAction).
+// 14. Let job be NewPromiseResolveThenableJob(promise, resolution, thenJobCallback).
+// 15. Perform HostEnqueuePromiseJob(job.[[Job]], job.[[Realm]]).
+// 16. Return undefined.
+
+// The "length" property of a promise resolve function is 1𝔽.
+/// ### [27.2.1.4 FulfillPromise ( promise, value )]()
+///
+/// The abstract operation FulfillPromise takes arguments promise (a Promise)
+/// and value (an ECMAScript language value) and returns unused.
+pub(crate) fn fulfill_promise(agent: &mut Agent, promise: Promise, value: Value) {
+    // 1. Assert: The value of promise.[[PromiseState]] is pending.
+    // 2. Let reactions be promise.[[PromiseFulfillReactions]].
+    // 3. Set promise.[[PromiseResult]] to value.
+    // 4. Set promise.[[PromiseFulfillReactions]] to undefined.
+    // 5. Set promise.[[PromiseRejectReactions]] to undefined.
+    // 6. Set promise.[[PromiseState]] to fulfilled.
+    // 7. Perform TriggerPromiseReactions(reactions, value).
+    // 8. Return unused.
+}
+
+/// ### [27.2.1.5 NewPromiseCapability ( C )]()
+///
+/// The abstract operation NewPromiseCapability takes argument C (an ECMAScript
+/// language value) and returns either a normal completion containing a
+/// PromiseCapability Record or a throw completion. It attempts to use C as a
+/// constructor in the fashion of the built-in Promise constructor to create a
+/// promise and extract its resolve and reject functions. The promise plus the
+/// resolve and reject functions are used to initialize a new PromiseCapability
+/// Record.
+pub(crate) fn new_promise_capability(agent: &mut Agent, c: Value) -> JsResult<PromiseCapability> {
+    // 1. If IsConstructor(C) is false, throw a TypeError exception.
+    if !is_constructor(agent, c) {
+        return Err(agent.throw_exception(ExceptionType::TypeError, "Not a constructor"));
+    }
+    // 2. NOTE: C is assumed to be a constructor function that supports the parameter conventions of the Promise constructor (see 27.2.3.1).
+    if c == agent.current_realm().intrinsics().promise().into_value() {
+        todo!("PromiseConstructor quick-route")
+    }
+
+    // 3. Let resolvingFunctions be the Record { [[Resolve]]: undefined, [[Reject]]: undefined }.
+    struct SettableResolvingFunction {
+        resolve: Option<Function>,
+        reject: Option<Function>,
+    }
+    let resolving_functions = SettableResolvingFunction {
+        resolve: None,
+        reject: None,
+    };
+
+    // 4. Let executorClosure be a new Abstract Closure with parameters (resolve, reject) that captures resolvingFunctions and performs the following steps when called:
+    agent.heap.abstract_closures.push(Some(AbstractClosureHeapData {
+        object_index: None,
+        length: 2,
+        realm: agent.current_realm_id(),
+        initial_name: Some(String::EMPTY_STRING),
+        behaviour: Box::new(|agent: &mut Agent, this_value: Value, arguments: Option<ArgumentsList>| {
+            // a. If resolvingFunctions.[[Resolve]] is not undefined, throw a TypeError exception.
+
+            // b. If resolvingFunctions.[[Reject]] is not undefined, throw a TypeError exception.
+            // c. Set resolvingFunctions.[[Resolve]] to resolve.
+            // d. Set resolvingFunctions.[[Reject]] to reject.
+            // e. Return undefined.
+            Ok(Value::Undefined)
+        }),
+    }));
+    // 5. Let executor be CreateBuiltinFunction(executorClosure, 2, "", « »).
+    // 6. Let promise be ? Construct(C, « executor »).
+    // 7. If IsCallable(resolvingFunctions.[[Resolve]]) is false, throw a TypeError exception.
+    // 8. If IsCallable(resolvingFunctions.[[Reject]]) is false, throw a TypeError exception.
+    // 9. Return the PromiseCapability Record { [[Promise]]: promise, [[Resolve]]: resolvingFunctions.[[Resolve]], [[Reject]]: resolvingFunctions.[[Reject]] }.
+    todo!();
+    // Note
+
+    // This abstract operation supports Promise subclassing, as it is generic
+    // on any constructor that calls a passed executor function argument in the
+    // same way as the Promise constructor. It is used to generalize static
+    // methods of the Promise constructor to any subclass.
+}
+
+/// ### [27.2.1.6 IsPromise ( x )]()
+///
+/// The abstract operation IsPromise takes argument x (an ECMAScript language
+/// value) and returns a Boolean. It checks for the promise brand on an object.
+pub(crate) fn is_promise(agent: &mut Agent, x: Value) -> bool {
+    // 1. If x is not an Object, return false.
+    // 2. If x does not have a [[PromiseState]] internal slot, return false.
+    // 3. Return true.
+    matches!(x, Value::Promise(_))
+}
+
+/// ### [27.2.1.7 RejectPromise ( promise, reason )]()
+///
+/// The abstract operation RejectPromise takes arguments promise (a Promise)
+/// and reason (an ECMAScript language value) and returns unused.
+pub(crate) fn reject_promise(agent: &mut Agent, promise: Promise, reason: Value) {
+    // 1. Assert: The value of promise.[[PromiseState]] is pending.
+    let promise = &mut agent[promise];
+    // 2. Let reactions be promise.[[PromiseRejectReactions]].
+    // 3. Set promise.[[PromiseResult]] to reason.
+    // 4. Set promise.[[PromiseFulfillReactions]] to undefined.
+    // 5. Set promise.[[PromiseRejectReactions]] to undefined.
+    // 6. Set promise.[[PromiseState]] to rejected.
+    // 7. If promise.[[PromiseIsHandled]] is false, perform HostPromiseRejectionTracker(promise, "reject").
+    // 8. Perform TriggerPromiseReactions(reactions, reason).
+    // 9. Return unused.
+}
+
+/// ### [27.2.1.8 TriggerPromiseReactions ( reactions, argument )]()
+///
+/// The abstract operation TriggerPromiseReactions takes arguments reactions (a
+/// List of PromiseReaction Records) and argument (an ECMAScript language
+/// value) and returns unused. It enqueues a new Job for each record in
+/// reactions. Each such Job processes the \[\[Type\]\] and \[\[Handler\]\] of
+/// the PromiseReaction Record, and if the \[\[Handler\]\] is not empty, calls
+/// it passing the given argument. If the \[\[Handler\]\] is empty, the
+/// behaviour is determined by the \[\[Type\]\].
+pub(crate) fn trigger_promise_reactions(agent: &mut Agent, reactions: &[PromiseReaction], argument: Value) {
+    // 1. For each element reaction of reactions, do
+    // a. Let job be NewPromiseReactionJob(reaction, argument).
+    // b. Perform HostEnqueuePromiseJob(job.[[Job]], job.[[Realm]]).
+    // 2. Return unused.
+}

nova_vm/src/ecmascript/builtins/control_abstraction_objects/promise_objects/promise_abstract_operations/promise_capability_records.rs

@@ -0,0 +1,97 @@
+//! ## [27.2.1.1 PromiseCapability Records]()
+
+use std::ops::{Index, IndexMut};
+
+use crate::{ecmascript::{abstract_operations::operations_on_objects::{call, call_function}, builtins::ArgumentsList, execution::{agent::JsError, Agent, JsResult}, types::{Function, IntoValue, Object, Value}}, heap::{indexes::BaseIndex, Heap}};
+
+
+#[derive(Debug, Clone, Copy)]
+pub(crate) struct PromiseCapabilityRecord {
+    /// \[\[Promise\]\] 
+    /// 
+    /// an Object 
+    /// 
+    /// An object that is usable as a promise.
+    pub(crate) promise: Object,
+    /// \[\[Resolve\]\] 
+    /// 
+    /// a function object 
+    /// 
+    /// The function that is used to resolve the given promise.
+    pub(crate) resolve: Function,
+    /// \[\[Reject\]\] 
+    /// 
+    /// a function object 
+    /// 
+    /// The function that is used to reject the given promise. 
+    pub(crate) reject: Function,
+}
+
+pub(crate) type PromiseCapability = BaseIndex<PromiseCapabilityRecord>;
+
+impl Index<PromiseCapability> for Agent {
+    type Output = PromiseCapabilityRecord;
+
+    fn index(&self, index: PromiseCapability) -> &Self::Output {
+        &self.heap[index]
+    }
+}
+
+impl IndexMut<PromiseCapability> for Agent {
+    fn index_mut(&mut self, index: PromiseCapability) -> &mut Self::Output {
+        &mut self.heap[index]
+    }
+}
+
+impl Index<PromiseCapability> for Heap {
+    type Output = PromiseCapabilityRecord;
+
+    fn index(&self, index: PromiseCapability) -> &Self::Output {
+        self.promise_capability_records
+            .get(index.into_index())
+            .expect("PromiseCapability out of bounds")
+            .as_ref()
+            .expect("PromiseCapability slot empty")
+    }
+}
+
+impl IndexMut<PromiseCapability> for Heap {
+    fn index_mut(&mut self, index: PromiseCapability) -> &mut Self::Output {
+        self.promise_capability_records
+            .get_mut(index.into_index())
+            .expect("PromiseCapability out of bounds")
+            .as_mut()
+            .expect("PromiseCapability slot empty")
+    }
+}
+
+/// ### [27.2.1.1.1 IfAbruptRejectPromise ( value, capability )](https://tc39.es/ecma262/#sec-ifabruptrejectpromise)
+///
+/// IfAbruptRejectPromise is a shorthand for a sequence of algorithm steps that
+/// use a PromiseCapability Record. An algorithm step of the form:
+///
+/// ```
+/// 1. IfAbruptRejectPromise(value, capability).
+/// ```
+///
+/// means the same thing as:
+/// ```
+/// 1. Assert: value is a Completion Record.
+/// 2. If value is an abrupt completion, then
+///     a. Perform ? Call(capability.[[Reject]], undefined, « value.[[Value]] »).
+///     b. Return capability.[[Promise]].
+/// 3. Else,
+///     a. Set value to ! value.
+/// ```
+#[inline(always)]
+pub(crate) fn if_abrupt_reject_promise<T>(agent: &mut Agent, value: JsResult<T>, capability: PromiseCapability) -> JsResult<T> {
+    value.or_else(|err| {
+        // If abrupt completion, call reject and make caller return the
+        // capability promise
+        let PromiseCapabilityRecord { promise,  reject, .. } = agent[capability];
+        call_function(agent, reject, Value::Undefined, Some(ArgumentsList(&[err.0])))?;
+        // Note: We return an error here so that caller gets to call this
+        // function with the ? operator
+        Err(JsError(promise.into_value()))
+    })
+}