JavaScriptCore-7601.1.46.3.tar.gz

[apple/javascriptcore.git] / builtins / Operations.Promise.js

diff --git a/builtins/Operations.Promise.js b/builtins/Operations.Promise.js
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+/*
+ * Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>.
+ *
+ * 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.
+ */
+
+function isPromise(promise)
+{
+    "use strict";
+
+    return @isObject(promise) && !!promise.@promiseState;
+}
+
+function newPromiseReaction(capability, handler)
+{
+    "use strict";
+
+    return {
+        @capabilities: capability,
+        @handler: handler
+    };
+}
+
+function newPromiseDeferred()
+{
+    "use strict";
+
+    return @newPromiseCapability(@Promise);
+}
+
+function newPromiseCapability(constructor)
+{
+    "use strict";
+
+    // FIXME: Check isConstructor(constructor).
+    if (typeof constructor !== "function")
+        throw new @TypeError("promise capability requires a constructor function");
+
+    var promiseCapability = {
+        @promise: undefined,
+        @resolve: undefined,
+        @reject: undefined
+    };
+
+    function executor(resolve, reject)
+    {
+        if (promiseCapability.@resolve !== undefined)
+            throw new @TypeError("resolve function is already set");
+        if (promiseCapability.@reject !== undefined)
+            throw new @TypeError("reject function is already set");
+
+        promiseCapability.@resolve = resolve;
+        promiseCapability.@reject = reject;
+    }
+
+    var promise = new constructor(executor);
+
+    if (typeof promiseCapability.@resolve !== "function")
+        throw new @TypeError("executor did not take a resolve function");
+
+    if (typeof promiseCapability.@reject !== "function")
+        throw new @TypeError("executor did not take a reject function");
+
+    promiseCapability.@promise = promise;
+
+    return promiseCapability;
+}
+
+function triggerPromiseReactions(reactions, argument)
+{
+    "use strict";
+
+    for (var index = 0, length = reactions.length; index < length; ++index)
+        @enqueueJob(@promiseReactionJob, [reactions[index], argument]);
+}
+
+function rejectPromise(promise, reason)
+{
+    "use strict";
+
+    var reactions = promise.@promiseRejectReactions;
+    promise.@promiseResult = reason;
+    promise.@promiseFulfillReactions = undefined;
+    promise.@promiseRejectReactions = undefined;
+    promise.@promiseState = @promiseRejected;
+    @triggerPromiseReactions(reactions, reason);
+}
+
+function fulfillPromise(promise, value)
+{
+    "use strict";
+
+    var reactions = promise.@promiseFulfillReactions;
+    promise.@promiseResult = value;
+    promise.@promiseFulfillReactions = undefined;
+    promise.@promiseRejectReactions = undefined;
+    promise.@promiseState = @promiseFulfilled;
+    @triggerPromiseReactions(reactions, value);
+}
+
+function createResolvingFunctions(promise)
+{
+    "use strict";
+
+    var alreadyResolved = false;
+
+    var resolve = function (resolution) {
+        if (alreadyResolved)
+            return undefined;
+        alreadyResolved = true;
+
+        if (resolution === promise)
+            return @rejectPromise(promise, new @TypeError("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 (typeof then !== 'function')
+            return @fulfillPromise(promise, resolution);
+
+        @enqueueJob(@promiseResolveThenableJob, [promise, resolution, then]);
+
+        return undefined;
+    };
+
+    var reject = function (reason) {
+        if (alreadyResolved)
+            return undefined;
+        alreadyResolved = true;
+
+        return @rejectPromise(promise, reason);
+    };
+
+    return {
+        @resolve: resolve,
+        @reject: reject
+    };
+}
+
+function promiseReactionJob(reaction, argument)
+{
+    "use strict";
+
+    var promiseCapability = reaction.@capabilities;
+
+    var result;
+    try {
+        result = reaction.@handler.@call(undefined, argument);
+    } catch (error) {
+        return promiseCapability.@reject.@call(undefined, error);
+    }
+
+    return promiseCapability.@resolve.@call(undefined, result);
+}
+
+function promiseResolveThenableJob(promiseToResolve, thenable, then)
+{
+    "use strict";
+
+    var resolvingFunctions = @createResolvingFunctions(promiseToResolve);
+
+    try {
+        return then.@call(thenable, resolvingFunctions.@resolve, resolvingFunctions.@reject);
+    } catch (error) {
+        return resolvingFunctions.@reject.@call(undefined, error);
+    }
+}
+
+function initializePromise(executor)
+{
+    "use strict";
+
+    if (typeof executor !== 'function')
+        throw new @TypeError("Promise constructor takes a function argument");
+
+    this.@promiseState = @promisePending;
+    this.@promiseFulfillReactions = [];
+    this.@promiseRejectReactions = [];
+
+    var resolvingFunctions = @createResolvingFunctions(this);
+    try {
+        executor(resolvingFunctions.@resolve, resolvingFunctions.@reject);
+    } catch (error) {
+        return resolvingFunctions.@reject.@call(undefined, error);
+    }
+
+    return this;
+}