Source/JavaScriptCore/builtins/PromiseOperations.js - WebKit - Git at Google

 /*
  * Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>.
  * Copyright (C) 2016-2019 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 // @internal

 @globalPrivate
 function newPromiseReaction(promiseOrCapability, onFulfilled, onRejected)
 {
     "use strict";

     return {
         @promiseOrCapability: promiseOrCapability,
         @onFulfilled: onFulfilled,
         @onRejected: onRejected,
         @next: @undefined,
     };
 }

 @globalPrivate
 function newPromiseCapabilitySlow(constructor)
 {
     var promiseCapability = {
         @resolve: @undefined,
         @reject: @undefined,
         @promise: @undefined,
     };

     var promise = new constructor((resolve, reject) => {
         if (promiseCapability.@resolve !== @undefined)
             @throwTypeError("resolve function is already set");
         if (promiseCapability.@reject !== @undefined)
             @throwTypeError("reject function is already set");

         promiseCapability.@resolve = resolve;
         promiseCapability.@reject = reject;
     });

     if (typeof promiseCapability.@resolve !== "function")
         @throwTypeError("executor did not take a resolve function");

     if (typeof promiseCapability.@reject !== "function")
         @throwTypeError("executor did not take a reject function");

     promiseCapability.@promise = promise;

     return promiseCapability;
 }

 @globalPrivate
 function newPromiseCapability(constructor)
 {
     "use strict";

     if (constructor === @Promise) {
         var promise = @newPromise();
         var capturedPromise = promise;
         function @resolve(resolution) {
             return @resolvePromiseWithFirstResolvingFunctionCallCheck(capturedPromise, resolution);
         }
         function @reject(reason) {
             return @rejectPromiseWithFirstResolvingFunctionCallCheck(capturedPromise, reason);
         }
         return { @resolve, @reject, @promise: promise };
     }

     return @newPromiseCapabilitySlow(constructor);
 }

 @globalPrivate
 function promiseResolveSlow(constructor, value)
 {
     @assert(constructor !== @Promise);
     var promiseCapability = @newPromiseCapabilitySlow(constructor);
     promiseCapability.@resolve.@call(@undefined, value);
     return promiseCapability.@promise;
 }

 @globalPrivate
 function promiseRejectSlow(constructor, reason)
 {
     @assert(constructor !== @Promise);
     var promiseCapability = @newPromiseCapabilitySlow(constructor);
     promiseCapability.@reject.@call(@undefined, reason);
     return promiseCapability.@promise;
 }

 @globalPrivate
 function newHandledRejectedPromise(error)
 {
     "use strict";
     var promise = @newPromise();
     @rejectPromiseWithFirstResolvingFunctionCallCheck(promise, error);
     @putPromiseInternalField(promise, @promiseFieldFlags, @getPromiseInternalField(promise, @promiseFieldFlags) | @promiseFlagsIsHandled);
     return promise;
 }

 @globalPrivate
 function triggerPromiseReactions(state, reactions, argument)
 {
     "use strict";

     // Reverse the order of singly-linked-list.
     var previous = @undefined;
     var current = reactions;
     while (current) {
         var next = current.@next;
         current.@next = previous;
         previous = current;
         current = next;
     }
     reactions = previous;

     current = reactions;
     while (current) {
         @enqueueJob(@promiseReactionJob, state, current, argument);
         current = current.@next;
     }
 }

 @globalPrivate
 function resolvePromise(promise, resolution)
 {
     "use strict";

     @assert(@isPromise(promise));

     if (resolution === promise)
         return @rejectPromise(promise, @makeTypeError("Cannot resolve a promise with itself"));

     if (!@isObject(resolution))
         return @fulfillPromise(promise, resolution);

     var then;
     try {
         then = resolution.then;
     } catch (error) {
         return @rejectPromise(promise, error);
     }

     if (@isPromise(resolution) && then === @defaultPromiseThen) {
         @enqueueJob(@promiseResolveThenableJobFast, resolution, promise);
         return;
     }

     if (typeof then !== 'function')
         return @fulfillPromise(promise, resolution);

     @enqueueJob(@promiseResolveThenableJob, resolution, then, @createResolvingFunctions(promise));
 }

 @globalPrivate
 function rejectPromise(promise, reason)
 {
     "use strict";

     @assert(@isPromise(promise));
     @assert((@getPromiseInternalField(promise, @promiseFieldFlags) & @promiseStateMask) == @promiseStatePending);

     var flags = @getPromiseInternalField(promise, @promiseFieldFlags);
     var reactions = @getPromiseInternalField(promise, @promiseFieldReactionsOrResult);
     @putPromiseInternalField(promise, @promiseFieldReactionsOrResult, reason);
     @putPromiseInternalField(promise, @promiseFieldFlags, flags | @promiseStateRejected);

     @InspectorInstrumentation.promiseRejected(promise, reason, reactions);

     if (!(flags & @promiseFlagsIsHandled))
         @hostPromiseRejectionTracker(promise, @promiseRejectionReject);

     @triggerPromiseReactions(@promiseStateRejected, reactions, reason);
 }

 @globalPrivate
 function fulfillPromise(promise, value)
 {
     "use strict";

     @assert(@isPromise(promise));
     @assert((@getPromiseInternalField(promise, @promiseFieldFlags) & @promiseStateMask) == @promiseStatePending);

     var flags = @getPromiseInternalField(promise, @promiseFieldFlags);
     var reactions = @getPromiseInternalField(promise, @promiseFieldReactionsOrResult);
     @putPromiseInternalField(promise, @promiseFieldReactionsOrResult, value);
     @putPromiseInternalField(promise, @promiseFieldFlags, flags | @promiseStateFulfilled);

     @InspectorInstrumentation.promiseFulfilled(promise, value, reactions);

     @triggerPromiseReactions(@promiseStateFulfilled, reactions, value);
 }

 @globalPrivate
 function resolvePromiseWithFirstResolvingFunctionCallCheck(promise, value)
 {
     @assert(@isPromise(promise));
     var flags = @getPromiseInternalField(promise, @promiseFieldFlags);
     if (flags & @promiseFlagsIsFirstResolvingFunctionCalled)
         return;
     @putPromiseInternalField(promise, @promiseFieldFlags, flags | @promiseFlagsIsFirstResolvingFunctionCalled);
     return @resolvePromise(promise, value);
 }

 @globalPrivate
 function rejectPromiseWithFirstResolvingFunctionCallCheck(promise, reason)
 {
     @assert(@isPromise(promise));
     var flags = @getPromiseInternalField(promise, @promiseFieldFlags);
     if (flags & @promiseFlagsIsFirstResolvingFunctionCalled)
         return;
     @putPromiseInternalField(promise, @promiseFieldFlags, flags | @promiseFlagsIsFirstResolvingFunctionCalled);
     return @rejectPromise(promise, reason);
 }

 @globalPrivate
 function createResolvingFunctions(promise)
 {
     "use strict";
     @assert(@isPromise(promise));

     var alreadyResolved = false;

     var resolve = (0, /* prevent function name inference */ (resolution) => {
         if (alreadyResolved)
             return @undefined;
         alreadyResolved = true;

         return @resolvePromise(promise, resolution);
     });

     var reject = (0, /* prevent function name inference */ (reason) => {
         if (alreadyResolved)
             return @undefined;
         alreadyResolved = true;

         return @rejectPromise(promise, reason);
     });

     return { @resolve: resolve, @reject: reject };
 }

 @globalPrivate
 function promiseReactionJobWithoutPromise(handler, argument)
 {
     "use strict";

     try {
         handler(argument);
     } catch {
         // This is user-uncatchable promise. We just ignore the error here.
     }
 }

 // This function has strong guarantee that each handler function (onFulfilled and onRejected) will be called at most once.
 @globalPrivate
 function resolveWithoutPromise(resolution, onFulfilled, onRejected)
 {
     "use strict";

     if (!@isObject(resolution)) {
         @fulfillWithoutPromise(resolution, onFulfilled, onRejected);
         return;
     }

     var then;
     try {
         then = resolution.then;
     } catch (error) {
         @rejectWithoutPromise(error, onFulfilled, onRejected);
         return;
     }

     if (@isPromise(resolution) && then === @defaultPromiseThen) {
         @enqueueJob(@promiseResolveThenableJobWithoutPromiseFast, resolution, onFulfilled, onRejected);
         return;
     }

     if (typeof then !== 'function') {
         @fulfillWithoutPromise(resolution, onFulfilled, onRejected);
         return;
     }

     // Wrap onFulfilled and onRejected with @createResolvingFunctionsWithoutPromise to ensure that each function will be called at most once.
     @enqueueJob(@promiseResolveThenableJob, resolution, then, @createResolvingFunctionsWithoutPromise(onFulfilled, onRejected));
 }

 // This function has strong guarantee that each handler function (onFulfilled and onRejected) will be called at most once.
 @globalPrivate
 function rejectWithoutPromise(reason, onFulfilled, onRejected)
 {
     "use strict";

     @enqueueJob(@promiseReactionJobWithoutPromise, onRejected, reason);
 }

 // This function has strong guarantee that each handler function (onFulfilled and onRejected) will be called at most once.
 @globalPrivate
 function fulfillWithoutPromise(value, onFulfilled, onRejected)
 {
     "use strict";

     @enqueueJob(@promiseReactionJobWithoutPromise, onFulfilled, value);
 }

 @globalPrivate
 function createResolvingFunctionsWithoutPromise(onFulfilled, onRejected)
 {
     "use strict";

     var alreadyResolved = false;

     var resolve = (0, /* prevent function name inference */ (resolution) => {
         if (alreadyResolved)
             return @undefined;
         alreadyResolved = true;

         @resolveWithoutPromise(resolution, onFulfilled, onRejected);
     });

     var reject = (0, /* prevent function name inference */ (reason) => {
         if (alreadyResolved)
             return @undefined;
         alreadyResolved = true;

         @rejectWithoutPromise(reason, onFulfilled, onRejected);
     });

     return { @resolve: resolve, @reject: reject };
 }

 @globalPrivate
 function promiseReactionJob(state, reaction, argument)
 {
     // Promise Reaction has four types.
     // 1. @promiseOrCapability is PromiseCapability, and having handlers.
     //     The most generic one.
     // 2. @promiseOrCapability is Promise, and having handlers.
     //     We just have promise.
     // 3. @promiseOrCapability is Promise, and not having handlers.
     //     It only has promise. Just resolving it with the value.
     // 4. Only having @onFulfilled and @onRejected
     //     It does not have promise capability. Just handlers are passed.
     "use strict";

     var promiseOrCapability = reaction.@promiseOrCapability;

     // Case (3).
     if (!reaction.@onRejected) {
         @assert(!reaction.@onFulfilled);
         try {
             @assert(@isPromise(promiseOrCapability));
             if (state === @promiseStateFulfilled)
                 @resolvePromise(promiseOrCapability, argument);
             else
                 @rejectPromise(promiseOrCapability, argument);
         } catch {
             // This is user-uncatchable promise. We just ignore the error here.
         }
         return;
     }

     var handler = (state === @promiseStateFulfilled) ? reaction.@onFulfilled: reaction.@onRejected;

     // Case (4).
     if (!promiseOrCapability) {
         @promiseReactionJobWithoutPromise(handler, argument);
         return;
     }

     // Case (1), or (2).
     var result;
     try {
         result = handler(argument);
     } catch (error) {
         if (@isPromise(promiseOrCapability)) {
             @rejectPromise(promiseOrCapability, error);
             return;
         }
         promiseOrCapability.@reject.@call(@undefined, error);
         return;
     }

     if (@isPromise(promiseOrCapability)) {
         @resolvePromise(promiseOrCapability, result);
         return;
     }
     promiseOrCapability.@resolve.@call(@undefined, result);
 }

 @globalPrivate
 function promiseResolveThenableJobFast(thenable, promiseToResolve)
 {
     "use strict";

     @assert(@isPromise(thenable));
     @assert(@isPromise(promiseToResolve));

     var flags = @getPromiseInternalField(thenable, @promiseFieldFlags);
     var state = flags & @promiseStateMask;
     var reaction = @newPromiseReaction(promiseToResolve, @undefined, @undefined);
     if (state === @promiseStatePending) {
         reaction.@next = @getPromiseInternalField(thenable, @promiseFieldReactionsOrResult);
         @putPromiseInternalField(thenable, @promiseFieldReactionsOrResult, reaction);
     } else {
         if (state === @promiseStateRejected && !(flags & @promiseFlagsIsHandled))
             @hostPromiseRejectionTracker(thenable, @promiseRejectionHandle);
         @enqueueJob(@promiseReactionJob, state, reaction, @getPromiseInternalField(thenable, @promiseFieldReactionsOrResult));
     }
     @putPromiseInternalField(thenable, @promiseFieldFlags, @getPromiseInternalField(thenable, @promiseFieldFlags) | @promiseFlagsIsHandled);
 }

 @globalPrivate
 function promiseResolveThenableJobWithoutPromiseFast(thenable, onFulfilled, onRejected)
 {
     "use strict";

     @assert(@isPromise(thenable));

     var flags = @getPromiseInternalField(thenable, @promiseFieldFlags);
     var state = flags & @promiseStateMask;
     if (state === @promiseStatePending) {
         var reaction = @newPromiseReaction(@undefined, onFulfilled, onRejected);
         reaction.@next = @getPromiseInternalField(thenable, @promiseFieldReactionsOrResult);
         @putPromiseInternalField(thenable, @promiseFieldReactionsOrResult, reaction);
     } else {
         var result = @getPromiseInternalField(thenable, @promiseFieldReactionsOrResult);
         if (state === @promiseStateRejected) {
             if (!(flags & @promiseFlagsIsHandled))
                 @hostPromiseRejectionTracker(thenable, @promiseRejectionHandle);
             @rejectWithoutPromise(result, onFulfilled, onRejected);
         } else
             @fulfillWithoutPromise(result, onFulfilled, onRejected);
     }
     @putPromiseInternalField(thenable, @promiseFieldFlags, @getPromiseInternalField(thenable, @promiseFieldFlags) | @promiseFlagsIsHandled);
 }

 @globalPrivate
 function promiseResolveThenableJob(thenable, then, resolvingFunctions)
 {
     "use strict";

     try {
         return then.@call(thenable, resolvingFunctions.@resolve, resolvingFunctions.@reject);
     } catch (error) {
         return resolvingFunctions.@reject.@call(@undefined, error);
     }
 }
	/*
	* Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>.
	* Copyright (C) 2016-2019 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
	* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	// @internal

	@globalPrivate
	function newPromiseReaction(promiseOrCapability, onFulfilled, onRejected)
	{
	"use strict";

	return {
	@promiseOrCapability: promiseOrCapability,
	@onFulfilled: onFulfilled,
	@onRejected: onRejected,
	@next: @undefined,
	};
	}

	@globalPrivate
	function newPromiseCapabilitySlow(constructor)
	{
	var promiseCapability = {
	@resolve: @undefined,
	@reject: @undefined,
	@promise: @undefined,
	};

	var promise = new constructor((resolve, reject) => {
	if (promiseCapability.@resolve !== @undefined)
	@throwTypeError("resolve function is already set");
	if (promiseCapability.@reject !== @undefined)
	@throwTypeError("reject function is already set");

	promiseCapability.@resolve = resolve;
	promiseCapability.@reject = reject;
	});

	if (typeof promiseCapability.@resolve !== "function")
	@throwTypeError("executor did not take a resolve function");

	if (typeof promiseCapability.@reject !== "function")
	@throwTypeError("executor did not take a reject function");

	promiseCapability.@promise = promise;

	return promiseCapability;
	}

	@globalPrivate
	function newPromiseCapability(constructor)
	{
	"use strict";

	if (constructor === @Promise) {
	var promise = @newPromise();
	var capturedPromise = promise;
	function @resolve(resolution) {
	return @resolvePromiseWithFirstResolvingFunctionCallCheck(capturedPromise, resolution);
	}
	function @reject(reason) {
	return @rejectPromiseWithFirstResolvingFunctionCallCheck(capturedPromise, reason);
	}
	return { @resolve, @reject, @promise: promise };
	}

	return @newPromiseCapabilitySlow(constructor);
	}

	@globalPrivate
	function promiseResolveSlow(constructor, value)
	{
	@assert(constructor !== @Promise);
	var promiseCapability = @newPromiseCapabilitySlow(constructor);
	promiseCapability.@resolve.@call(@undefined, value);
	return promiseCapability.@promise;
	}

	@globalPrivate
	function promiseRejectSlow(constructor, reason)
	{
	@assert(constructor !== @Promise);
	var promiseCapability = @newPromiseCapabilitySlow(constructor);
	promiseCapability.@reject.@call(@undefined, reason);
	return promiseCapability.@promise;
	}

	@globalPrivate
	function newHandledRejectedPromise(error)
	{
	"use strict";
	var promise = @newPromise();
	@rejectPromiseWithFirstResolvingFunctionCallCheck(promise, error);
	@putPromiseInternalField(promise, @promiseFieldFlags, @getPromiseInternalField(promise, @promiseFieldFlags) \| @promiseFlagsIsHandled);
	return promise;
	}

	@globalPrivate
	function triggerPromiseReactions(state, reactions, argument)
	{
	"use strict";

	// Reverse the order of singly-linked-list.
	var previous = @undefined;
	var current = reactions;
	while (current) {
	var next = current.@next;
	current.@next = previous;
	previous = current;
	current = next;
	}
	reactions = previous;

	current = reactions;
	while (current) {
	@enqueueJob(@promiseReactionJob, state, current, argument);
	current = current.@next;
	}
	}

	@globalPrivate
	function resolvePromise(promise, resolution)
	{
	"use strict";

	@assert(@isPromise(promise));

	if (resolution === promise)
	return @rejectPromise(promise, @makeTypeError("Cannot resolve a promise with itself"));

	if (!@isObject(resolution))
	return @fulfillPromise(promise, resolution);

	var then;
	try {
	then = resolution.then;
	} catch (error) {
	return @rejectPromise(promise, error);
	}

	if (@isPromise(resolution) && then === @defaultPromiseThen) {
	@enqueueJob(@promiseResolveThenableJobFast, resolution, promise);
	return;
	}

	if (typeof then !== 'function')
	return @fulfillPromise(promise, resolution);

	@enqueueJob(@promiseResolveThenableJob, resolution, then, @createResolvingFunctions(promise));
	}

	@globalPrivate
	function rejectPromise(promise, reason)
	{
	"use strict";

	@assert(@isPromise(promise));
	@assert((@getPromiseInternalField(promise, @promiseFieldFlags) & @promiseStateMask) == @promiseStatePending);

	var flags = @getPromiseInternalField(promise, @promiseFieldFlags);
	var reactions = @getPromiseInternalField(promise, @promiseFieldReactionsOrResult);
	@putPromiseInternalField(promise, @promiseFieldReactionsOrResult, reason);
	@putPromiseInternalField(promise, @promiseFieldFlags, flags \| @promiseStateRejected);

	@InspectorInstrumentation.promiseRejected(promise, reason, reactions);

	if (!(flags & @promiseFlagsIsHandled))
	@hostPromiseRejectionTracker(promise, @promiseRejectionReject);

	@triggerPromiseReactions(@promiseStateRejected, reactions, reason);
	}

	@globalPrivate
	function fulfillPromise(promise, value)
	{
	"use strict";

	@assert(@isPromise(promise));
	@assert((@getPromiseInternalField(promise, @promiseFieldFlags) & @promiseStateMask) == @promiseStatePending);

	var flags = @getPromiseInternalField(promise, @promiseFieldFlags);
	var reactions = @getPromiseInternalField(promise, @promiseFieldReactionsOrResult);
	@putPromiseInternalField(promise, @promiseFieldReactionsOrResult, value);
	@putPromiseInternalField(promise, @promiseFieldFlags, flags \| @promiseStateFulfilled);

	@InspectorInstrumentation.promiseFulfilled(promise, value, reactions);

	@triggerPromiseReactions(@promiseStateFulfilled, reactions, value);
	}

	@globalPrivate
	function resolvePromiseWithFirstResolvingFunctionCallCheck(promise, value)
	{
	@assert(@isPromise(promise));
	var flags = @getPromiseInternalField(promise, @promiseFieldFlags);
	if (flags & @promiseFlagsIsFirstResolvingFunctionCalled)
	return;
	@putPromiseInternalField(promise, @promiseFieldFlags, flags \| @promiseFlagsIsFirstResolvingFunctionCalled);
	return @resolvePromise(promise, value);
	}

	@globalPrivate
	function rejectPromiseWithFirstResolvingFunctionCallCheck(promise, reason)
	{
	@assert(@isPromise(promise));
	var flags = @getPromiseInternalField(promise, @promiseFieldFlags);
	if (flags & @promiseFlagsIsFirstResolvingFunctionCalled)
	return;
	@putPromiseInternalField(promise, @promiseFieldFlags, flags \| @promiseFlagsIsFirstResolvingFunctionCalled);
	return @rejectPromise(promise, reason);
	}

	@globalPrivate
	function createResolvingFunctions(promise)
	{
	"use strict";
	@assert(@isPromise(promise));

	var alreadyResolved = false;

	var resolve = (0, /* prevent function name inference */ (resolution) => {
	if (alreadyResolved)
	return @undefined;
	alreadyResolved = true;

	return @resolvePromise(promise, resolution);
	});

	var reject = (0, /* prevent function name inference */ (reason) => {
	if (alreadyResolved)
	return @undefined;
	alreadyResolved = true;

	return @rejectPromise(promise, reason);
	});

	return { @resolve: resolve, @reject: reject };
	}

	@globalPrivate
	function promiseReactionJobWithoutPromise(handler, argument)
	{
	"use strict";

	try {
	handler(argument);
	} catch {
	// This is user-uncatchable promise. We just ignore the error here.
	}
	}

	// This function has strong guarantee that each handler function (onFulfilled and onRejected) will be called at most once.
	@globalPrivate
	function resolveWithoutPromise(resolution, onFulfilled, onRejected)
	{
	"use strict";

	if (!@isObject(resolution)) {
	@fulfillWithoutPromise(resolution, onFulfilled, onRejected);
	return;
	}

	var then;
	try {
	then = resolution.then;
	} catch (error) {
	@rejectWithoutPromise(error, onFulfilled, onRejected);
	return;
	}

	if (@isPromise(resolution) && then === @defaultPromiseThen) {
	@enqueueJob(@promiseResolveThenableJobWithoutPromiseFast, resolution, onFulfilled, onRejected);
	return;
	}

	if (typeof then !== 'function') {
	@fulfillWithoutPromise(resolution, onFulfilled, onRejected);
	return;
	}

	// Wrap onFulfilled and onRejected with @createResolvingFunctionsWithoutPromise to ensure that each function will be called at most once.
	@enqueueJob(@promiseResolveThenableJob, resolution, then, @createResolvingFunctionsWithoutPromise(onFulfilled, onRejected));
	}

	// This function has strong guarantee that each handler function (onFulfilled and onRejected) will be called at most once.
	@globalPrivate
	function rejectWithoutPromise(reason, onFulfilled, onRejected)
	{
	"use strict";

	@enqueueJob(@promiseReactionJobWithoutPromise, onRejected, reason);
	}

	// This function has strong guarantee that each handler function (onFulfilled and onRejected) will be called at most once.
	@globalPrivate
	function fulfillWithoutPromise(value, onFulfilled, onRejected)
	{
	"use strict";

	@enqueueJob(@promiseReactionJobWithoutPromise, onFulfilled, value);
	}

	@globalPrivate
	function createResolvingFunctionsWithoutPromise(onFulfilled, onRejected)
	{
	"use strict";

	var alreadyResolved = false;

	var resolve = (0, /* prevent function name inference */ (resolution) => {
	if (alreadyResolved)
	return @undefined;
	alreadyResolved = true;

	@resolveWithoutPromise(resolution, onFulfilled, onRejected);
	});

	var reject = (0, /* prevent function name inference */ (reason) => {
	if (alreadyResolved)
	return @undefined;
	alreadyResolved = true;

	@rejectWithoutPromise(reason, onFulfilled, onRejected);
	});

	return { @resolve: resolve, @reject: reject };
	}

	@globalPrivate
	function promiseReactionJob(state, reaction, argument)
	{
	// Promise Reaction has four types.
	// 1. @promiseOrCapability is PromiseCapability, and having handlers.
	// The most generic one.
	// 2. @promiseOrCapability is Promise, and having handlers.
	// We just have promise.
	// 3. @promiseOrCapability is Promise, and not having handlers.
	// It only has promise. Just resolving it with the value.
	// 4. Only having @onFulfilled and @onRejected
	// It does not have promise capability. Just handlers are passed.
	"use strict";

	var promiseOrCapability = reaction.@promiseOrCapability;

	// Case (3).
	if (!reaction.@onRejected) {
	@assert(!reaction.@onFulfilled);
	try {
	@assert(@isPromise(promiseOrCapability));
	if (state === @promiseStateFulfilled)
	@resolvePromise(promiseOrCapability, argument);
	else
	@rejectPromise(promiseOrCapability, argument);
	} catch {
	// This is user-uncatchable promise. We just ignore the error here.
	}
	return;
	}

	var handler = (state === @promiseStateFulfilled) ? reaction.@onFulfilled: reaction.@onRejected;

	// Case (4).
	if (!promiseOrCapability) {
	@promiseReactionJobWithoutPromise(handler, argument);
	return;
	}

	// Case (1), or (2).
	var result;
	try {
	result = handler(argument);
	} catch (error) {
	if (@isPromise(promiseOrCapability)) {
	@rejectPromise(promiseOrCapability, error);
	return;
	}
	promiseOrCapability.@reject.@call(@undefined, error);
	return;
	}

	if (@isPromise(promiseOrCapability)) {
	@resolvePromise(promiseOrCapability, result);
	return;
	}
	promiseOrCapability.@resolve.@call(@undefined, result);
	}

	@globalPrivate
	function promiseResolveThenableJobFast(thenable, promiseToResolve)
	{
	"use strict";

	@assert(@isPromise(thenable));
	@assert(@isPromise(promiseToResolve));

	var flags = @getPromiseInternalField(thenable, @promiseFieldFlags);
	var state = flags & @promiseStateMask;
	var reaction = @newPromiseReaction(promiseToResolve, @undefined, @undefined);
	if (state === @promiseStatePending) {
	reaction.@next = @getPromiseInternalField(thenable, @promiseFieldReactionsOrResult);
	@putPromiseInternalField(thenable, @promiseFieldReactionsOrResult, reaction);
	} else {
	if (state === @promiseStateRejected && !(flags & @promiseFlagsIsHandled))
	@hostPromiseRejectionTracker(thenable, @promiseRejectionHandle);
	@enqueueJob(@promiseReactionJob, state, reaction, @getPromiseInternalField(thenable, @promiseFieldReactionsOrResult));
	}
	@putPromiseInternalField(thenable, @promiseFieldFlags, @getPromiseInternalField(thenable, @promiseFieldFlags) \| @promiseFlagsIsHandled);
	}

	@globalPrivate
	function promiseResolveThenableJobWithoutPromiseFast(thenable, onFulfilled, onRejected)
	{
	"use strict";

	@assert(@isPromise(thenable));

	var flags = @getPromiseInternalField(thenable, @promiseFieldFlags);
	var state = flags & @promiseStateMask;
	if (state === @promiseStatePending) {
	var reaction = @newPromiseReaction(@undefined, onFulfilled, onRejected);
	reaction.@next = @getPromiseInternalField(thenable, @promiseFieldReactionsOrResult);
	@putPromiseInternalField(thenable, @promiseFieldReactionsOrResult, reaction);
	} else {
	var result = @getPromiseInternalField(thenable, @promiseFieldReactionsOrResult);
	if (state === @promiseStateRejected) {
	if (!(flags & @promiseFlagsIsHandled))
	@hostPromiseRejectionTracker(thenable, @promiseRejectionHandle);
	@rejectWithoutPromise(result, onFulfilled, onRejected);
	} else
	@fulfillWithoutPromise(result, onFulfilled, onRejected);
	}
	@putPromiseInternalField(thenable, @promiseFieldFlags, @getPromiseInternalField(thenable, @promiseFieldFlags) \| @promiseFlagsIsHandled);
	}

	@globalPrivate
	function promiseResolveThenableJob(thenable, then, resolvingFunctions)
	{
	"use strict";

	try {
	return then.@call(thenable, resolvingFunctions.@resolve, resolvingFunctions.@reject);
	} catch (error) {
	return resolvingFunctions.@reject.@call(@undefined, error);
	}
	}