From 2f52c596b061f311a0e84278eb35c314d6922a22 Mon Sep 17 00:00:00 2001
From: Vladimir Enchev <vladimir.enchev@telerik.com>
Date: Tue, 15 Apr 2014 17:15:04 +0300
Subject: [PATCH] promises changed to different (generic) library

---
 net/http_client.android.ts |  12 +-
 net/http_client.d.ts       |   6 +-
 net/http_client.ios.ts     |  12 +-
 promises/promises.ts       | 497 +++++++++++++++++++++++++++++++------
 4 files changed, 433 insertions(+), 94 deletions(-)

diff --git a/net/http_client.android.ts b/net/http_client.android.ts
index 685346eb4..c330784ae 100644
--- a/net/http_client.android.ts
+++ b/net/http_client.android.ts
@@ -10,8 +10,8 @@ export class http {
     /**
       * Gets string from url.
       */
-    public static getString(url: string): promises.Promise {
-        var d = new promises.Deferred();
+    public static getString(url: string): promises.Promise<string> {
+        var d = promises.defer<string>();
         http.get(url, r => d.resolve(r), e => d.reject(e));
         return d.promise();
     }
@@ -19,8 +19,8 @@ export class http {
     /**
       * Gets JSON from url.
       */
-    public static getJSON(url: string): promises.Promise {
-        var d = new promises.Deferred();
+    public static getJSON<T>(url: string): promises.Promise<T> {
+        var d = promises.defer<T>();
         http.get(url, r => d.resolve(JSON.parse(r)), e => d.reject(e));
         return d.promise();
     }
@@ -28,8 +28,8 @@ export class http {
     /**
       * Gets image from url.
       */
-    public static getImage(url: string): promises.Promise {
-        var d = new promises.Deferred();
+    public static getImage(url: string): promises.Promise<image_module.Image> {
+        var d = promises.defer<image_module.Image>();
         http.get(url, r => {
             var image = new image_module.Image();
             image.loadFromBitmap(r);
diff --git a/net/http_client.d.ts b/net/http_client.d.ts
index d726dede1..4ff9da2d0 100644
--- a/net/http_client.d.ts
+++ b/net/http_client.d.ts
@@ -5,7 +5,7 @@ import image_module = require("Image/image");
 import promises = require("promises/promises");
 
 export declare class http {
-    private static getString(url: string): promises.Promise;
-    private static getJSON(url: string): promises.Promise;
-    private static getImage(url: string): promises.Promise;
+    static getString(url: string): promises.Promise<string>;
+    static getJSON<T>(url: string): promises.Promise<T>;
+    static getImage(url: string): promises.Promise<image_module.Image>;
 }
\ No newline at end of file
diff --git a/net/http_client.ios.ts b/net/http_client.ios.ts
index 5db1880dd..ea700c402 100644
--- a/net/http_client.ios.ts
+++ b/net/http_client.ios.ts
@@ -9,8 +9,8 @@ export class http {
     /**
       * Gets string from url.
       */
-    public static getString(url : string) : promises.Promise {
-        var d = new promises.Deferred();
+    public static getString(url: string): promises.Promise<string> {
+        var d = promises.defer<string>();
         http.get(url, r => d.resolve(Foundation.NSString.initWithDataEncoding(r, 4).toString()), e => d.reject(e));
         return d.promise();
     }
@@ -18,8 +18,8 @@ export class http {
     /**
       * Gets JSON from url.
       */
-    public static getJSON(url: string) : promises.Promise {
-        var d = new promises.Deferred();
+    public static getJSON<T>(url: string): promises.Promise<T> {
+        var d = promises.defer<T>();
         http.get(url, r => d.resolve(JSON.parse(Foundation.NSString.initWithDataEncoding(r, 4).toString())), e => d.reject(e));
         return d.promise();
     }
@@ -27,8 +27,8 @@ export class http {
     /**
       * Gets image from url.
       */
-    public static getImage(url: string) : promises.Promise {
-        var d = new promises.Deferred();
+    public static getImage(url: string): promises.Promise<image_module.Image> {
+        var d = promises.defer<image_module.Image>();
         http.get(url, r => {
             var image = new image_module.Image();
             image.loadFromData(r);
diff --git a/promises/promises.ts b/promises/promises.ts
index 756f855d5..a970b87e9 100644
--- a/promises/promises.ts
+++ b/promises/promises.ts
@@ -1,110 +1,449 @@
-export function when(...promises: Promise[]): Promise {
-    var all_done = new Deferred();
-    var results = [];
-    var remaining = promises.length;
+/**
+    Module P: Generic Promises for TypeScript
 
-    promises.map(
-        (p, i) => {
-            p.then(
-                function (...args: any[]) {
-                    results[i] = args;
-                    remaining--;
-                    if (!remaining && all_done.status() !== 'rejected') {
-                        all_done.resolve.apply(all_done, results);
-                    }
-                },
-                function () { all_done.reject() }
-                );
+    Project, documentation, and license: https://github.com/pragmatrix/Promise
+*/
+
+
+
+/**
+    Returns a new "Deferred" value that may be resolved or rejected.
+*/
+
+export function defer<Value>(): Deferred<Value> {
+    return new DeferredI<Value>();
+}
+
+/**
+    Converts a value to a resolved promise.
+*/
+
+export function resolve<Value>(v: Value): Promise<Value> {
+    return defer<Value>().resolve(v).promise();
+}
+
+/**
+    Returns a rejected promise.
+*/
+
+export function reject<Value>(err: Rejection): Promise<Value> {
+    return defer<Value>().reject(err).promise();
+}
+
+/**
+    http://en.wikipedia.org/wiki/Anamorphism
+
+    Given a seed value, unfold calls the unspool function, waits for the returned promise to be resolved, and then 
+    calls it again if a next seed value was returned.
+
+    All the values of all promise results are collected into the resulting promise which is resolved as soon
+    the last generated element value is resolved.
+*/
+
+export function unfold<Seed, Element>(
+    unspool: (current: Seed) => { promise: Promise<Element>; next?: Seed },
+    seed: Seed)
+    : Promise<Element[]> {
+    var d = defer<Element[]>();
+    var elements: Element[] = new Array<Element>();
+
+    unfoldCore<Seed, Element>(elements, d, unspool, seed)
+
+		return d.promise();
+}
+
+function unfoldCore<Seed, Element>(
+    elements: Element[],
+    deferred: Deferred<Element[]>,
+    unspool: (current: Seed) => { promise: Promise<Element>; next?: Seed },
+    seed: Seed): void {
+    var result = unspool(seed);
+    if (!result) {
+        deferred.resolve(elements);
+        return;
+    }
+
+    // fastpath: don't waste stack space if promise resolves immediately.
+
+    while (result.next && result.promise.status == Status.Resolved) {
+        elements.push(result.promise.result);
+        result = unspool(result.next);
+        if (!result) {
+            deferred.resolve(elements);
+            return;
         }
-        );
-
-    if (!remaining) {
-        all_done.resolve.apply(all_done, results);
     }
 
-    return all_done.promise();
+    result.promise
+        .done(v => {
+            elements.push(v);
+            if (!result.next)
+                deferred.resolve(elements);
+            else
+                unfoldCore<Seed, Element>(elements, deferred, unspool, result.next);
+        })
+        .fail(e => {
+            deferred.reject(e);
+        });
 }
 
-export class Promise {
+/**
+    The status of a Promise. Initially a Promise is Unfulfilled and may
+    change to Rejected or Resolved.
+	 
+    Once a promise is either Rejected or Resolved, it can not change its 
+    status anymore.
+*/
 
-    constructor(private deferred: Deferred) { }
+export enum Status {
+    Unfulfilled,
+    Rejected,
+    Resolved
+}
 
-    then(callback: Function, error?: Function): Promise {
-        return this.deferred.then(callback, error);
+/**
+    If a promise gets rejected, at least a message that indicates the error or
+    reason for the rejection must be provided.
+*/
+
+export interface Rejection {
+    message: string;
+}
+
+/**
+    Both Promise<T> and Deferred<T> share these properties.
+*/
+
+export interface PromiseState<Value> {
+    /// The current status of the promise.
+    status: Status;
+
+    /// If the promise got resolved, the result of the promise.
+    result?: Value;
+
+    /// If the promise got rejected, the rejection message.
+    error?: Rejection;
+}
+
+/**
+    A Promise<Value> supports basic composition and registration of handlers that are called when the 
+    promise is fulfilled.
+
+    When multiple handlers are registered with done(), fail(), or always(), they are called in the 
+    same order.
+*/
+
+export interface Promise<Value> extends PromiseState<Value> {
+    /**
+        Returns a promise that represents a promise chain that consists of this
+        promise and the promise that is returned by the function provided.
+        The function receives the value of this promise as soon it is resolved.
+			
+        If this promise fails, the function is never called and the returned promise 
+        will also fail.
+    */
+    then<T2>(f: (v: Value) => Promise<T2>): Promise<T2>;
+    then<T2>(f: (v: Value) => T2): Promise<T2>;
+
+    /// Add a handler that is called when the promise gets resolved.
+    done(f: (v: Value) => void): Promise<Value>;
+    /// Add a handler that is called when the promise gets rejected.
+    fail(f: (err: Rejection) => void): Promise<Value>;
+    /// Add a handler that is called when the promise gets fulfilled (either resolved or rejected).
+    always(f: (v?: Value, err?: Rejection) => void): Promise<Value>;
+}
+
+/**
+    Deferred<Value> supports the explicit resolving and rejecting of the 
+    promise and the registration of fulfillment handlers.
+
+    A Deferred<Value> should be only visible to the function that initially sets up
+    an asynchronous process. Callers of that function should only see the Promise<Value> that
+    is returned by promise().
+*/
+
+export interface Deferred<Value> extends PromiseState<Value> {
+    /// Returns the encapsulated promise of this deferred instance.
+    /// The returned promise supports composition but removes the ability to resolve or reject
+    /// the promise.
+    promise(): Promise<Value>;
+
+    /// Resolve the promise.
+    resolve(result: Value): Deferred<Value>;
+    /// Reject the promise.
+    reject(err: Rejection): Deferred<Value>;
+
+    done(f: (v: Value) => void): Deferred<Value>;
+    fail(f: (err: Rejection) => void): Deferred<Value>;
+    always(f: (v?: Value, err?: Rejection) => void): Deferred<Value>;
+}
+
+/**
+    Creates a promise that gets resolved when all the promises in the argument list get resolved.
+    As soon one of the arguments gets rejected, the resulting promise gets rejected.
+    If no promises were provided, the resulting promise is immediately resolved.
+*/
+
+export function when(...promises: Promise<any>[]): Promise<any[]> {
+    var allDone = defer<any[]>();
+    if (!promises.length) {
+        allDone.resolve([]);
+        return allDone.promise();
     }
 
-    status(): string { return this.deferred.status() }
-    result(): any[] { return this.deferred.result() }
+    var resolved = 0;
+    var results = [];
+
+    promises.forEach((p, i) => {
+        p
+            .done(v => {
+                results[i] = v;
+                ++resolved;
+                if (resolved === promises.length && allDone.status !== Status.Rejected)
+                    allDone.resolve(results);
+            })
+            .fail(e => {
+                if (allDone.status !== Status.Rejected)
+                    allDone.reject(new Error("when: one or more promises were rejected"));
+            });
+    });
+
+    return allDone.promise();
 }
 
-export class Deferred {
+/**
+    Implementation of a promise.
 
-    private resolved: Function[] = [];
-    private rejected: Function[] = [];
-    private _status: string;
-    private _result: any[];
-    private _promise: Promise;
+    The Promise<Value> instance is a proxy to the Deferred<Value> instance.
+*/
+
+class PromiseI<Value> implements Promise<Value>
+{
+    constructor(public deferred: DeferredI<Value>)
+    { }
+
+    get status(): Status { return this.deferred.status; }
+    get result(): Value { return this.deferred.result; }
+    get error(): Rejection { return this.deferred.error; }
+
+    done(f: (v: Value) => void): Promise<Value> {
+        this.deferred.done(f);
+        return this;
+    }
+
+    fail(f: (err: Rejection) => void): Promise<Value> {
+        this.deferred.fail(f);
+        return this;
+    }
+
+    always(f: (v?: Value, err?: Rejection) => void): Promise<Value> {
+        this.deferred.always(f);
+        return this;
+    }
+
+    then<T2>(f: (v: Value) => any): Promise<T2> {
+        return this.deferred.then<any>(f);
+    }
+}
+
+/**
+    Implementation of a deferred.
+*/
+
+class DeferredI<Value> implements Deferred<Value>{
+
+    private _resolved: (v: Value) => void = _ => { };
+    private _rejected: (err: Rejection) => void = _ => { };
+
+    private _status: Status = Status.Unfulfilled;
+    private _result: Value;
+    private _error: Rejection = { message: "" };
+    private _promise: Promise<Value>;
 
     constructor() {
-        this._promise = new Promise(this);
-        this._status = 'in progress';
+        this._promise = new PromiseI<Value>(this);
     }
 
-    promise(): Promise { return this._promise }
-    status(): string { return this._status }
-    result(): any[] { return this._result }
-
-    resolve(...result: any[]): Deferred {
-        this._result = result;
-        this.notify(this.resolved, result);
-        this.resolved = [];
-        this._status = 'resolved';
-        return this;
+    promise(): Promise<Value> {
+        return this._promise;
     }
 
-    reject(...result: any[]): Deferred {
-        this._result = result;
-        this.notify(this.rejected, result);
-        this.rejected = [];
-        this._status = 'rejected';
-        return this;
+    get status(): Status {
+        return this._status;
     }
 
-    then(callback: Function, error: Function): Promise {
-        var d = new Deferred();
+    get result(): Value {
+        if (this._status != Status.Resolved)
+            throw new Error("Promise: result not available");
+        return this._result;
+    }
 
-        this.resolved.push(this.wrap(d, callback, 'resolve'));
+    get error(): Rejection {
+        if (this._status != Status.Rejected)
+            throw new Error("Promise: rejection reason not available");
+        return this._error;
+    }
 
-        if (error) {
-            this.rejected.push(this.wrap(d, error, 'reject'));
-        }
+    then<Result>(f: (v: Value) => any): Promise<Result> {
+        var d = defer<Result>();
 
-        if (this._status === 'resolved') {
-            this.resolve.apply(this, this.result);
-        }
-        else if (this._status === 'rejected' && error) {
-            this.reject.apply(this, this.result);
-        }
+        this
+            .done(v => {
+                var promiseOrValue = f(v);
+
+                // todo: need to find another way to check if r is really of interface
+                // type Promise<any>, otherwise we would not support other 
+                // implementations here.
+                if (promiseOrValue instanceof PromiseI) {
+                    var p = <Promise<Result>> promiseOrValue;
+                    p.done(v2 => d.resolve(v2))
+                        .fail(err => d.reject(err));
+                    return p;
+                }
+
+                d.resolve(promiseOrValue);
+            })
+            .fail(err => d.reject(err));
 
         return d.promise();
     }
 
-    private wrap(d: Deferred, f: Function, method: string): Function {
-            return function (...args: any[]) {
-            var result = f.apply(f, args);
-            if (result && result instanceof Promise) {
-                result.then(
-                    function () { d.resolve() },
-                    function () { d.reject() }
-                    );
-            }
-            else {
-                d[method].apply(d, typeof result === 'array' ? result : [result]);
-            }
-        }
+    done(f: (v: Value) => void): Deferred<Value> {
+        if (this.status === Status.Resolved) {
+            f(this._result);
+            return this;
         }
 
-    private notify(funcs: Function[], result: any[]): void {
-        funcs.map((f) => { f.apply(f, result) });
+        if (this.status !== Status.Unfulfilled)
+            return this;
+
+        var prev = this._resolved;
+        this._resolved = v => { prev(v); f(v); }
+
+			return this;
     }
-}
\ No newline at end of file
+
+    fail(f: (err: Rejection) => void): Deferred<Value> {
+        if (this.status === Status.Rejected) {
+            f(this._error);
+            return this;
+        }
+
+        if (this.status !== Status.Unfulfilled)
+            return this;
+
+        var prev = this._rejected;
+        this._rejected = e => { prev(e); f(e); }
+
+			return this;
+    }
+
+    always(f: (v?: Value, err?: Rejection) => void): Deferred<Value> {
+        this
+            .done(v => f(v))
+            .fail(err => f(null, err));
+
+        return this;
+    }
+
+    resolve(result: Value) {
+        if (this._status !== Status.Unfulfilled)
+            throw new Error("tried to resolve a fulfilled promise");
+
+        this._result = result;
+        this._status = Status.Resolved;
+        this._resolved(result);
+
+        this.detach();
+        return this;
+    }
+
+    reject(err: Rejection) {
+        if (this._status !== Status.Unfulfilled)
+            throw new Error("tried to reject a fulfilled promise");
+
+        this._error = err;
+        this._status = Status.Rejected;
+        this._rejected(err);
+
+        this.detach();
+        return this;
+    }
+
+    private detach() {
+        this._resolved = _ => { };
+        this._rejected = _ => { };
+    }
+}
+
+/**
+    Promise Generators and Iterators.
+*/
+
+export interface Generator<E> {
+    (): Iterator<E>;
+}
+
+export interface Iterator<E> {
+    advance(): Promise<boolean>;
+    current: E;
+}
+
+export function generator<E>(g: () => () => Promise<E>): Generator<E> {
+    return () => iterator<E>(g());
+};
+
+export function iterator<E>(f: () => Promise<E>): Iterator<E> {
+    return new IteratorI<E>(f);
+}
+
+class IteratorI<E> implements Iterator<E>
+{
+    current: E = undefined;
+
+    constructor(private f: () => Promise<E>)
+    { }
+
+    advance(): Promise<boolean> {
+        var res = this.f();
+        return res.then(value => {
+            if (isUndefined(value))
+                return false;
+
+            this.current = value;
+            return true;
+        });
+    }
+}
+
+/**
+    Iterator functions.
+*/
+
+export function each<E>(gen: Generator<E>, f: (e: E) => void): Promise<{}> {
+    var d = defer();
+    eachCore(d, gen(), f);
+    return d.promise();
+}
+
+function eachCore<E>(fin: Deferred<{}>, it: Iterator<E>, f: (e: E) => void): void {
+    it.advance()
+        .done(hasValue => {
+            if (!hasValue) {
+                fin.resolve({});
+                return;
+            }
+
+            f(it.current)
+				eachCore<E>(fin, it, f);
+        })
+        .fail(err => fin.reject(err));
+}
+
+/**
+    std
+*/
+
+export function isUndefined(v) {
+    return typeof v === 'undefined';
+}