working on mol-task

src/examples/computation.ts

-// TODO
+/**
\ No newline at end of file
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+import { Task, ExecuteSynchronous } from 'mol-task'
+
+async function test() {
+    const t = Task.create('test', async () => 1);
+    const r = await ExecuteSynchronous(t);
+    console.log(r);
+}
+
+test();
\ No newline at end of file

src/mol-task/execution/immediate.ts

+/**
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+/**
+ * setImmediate polyfill adapted from https://github.com/YuzuJS/setImmediate
+ * Copyright (c) 2012 Barnesandnoble.com, llc, Donavon West, and Domenic Denicola
+ * MIT license.
+ */
+
+function createImmediateActions() {
+    type Callback = (...args: any[]) => void;
+    type Task = { callback: Callback, args: any[] }
+
+    const tasksByHandle: { [handle: number]: Task } = { };
+    const doc = typeof document !== 'undefined' ? document : void 0;
+
+    let currentlyRunningATask = false;
+    let nextHandle = 1; // Spec says greater than zero
+    let registerImmediate: ((handle: number) => void);
+
+    function setImmediate(callback: Callback, ...args: any[]) {
+      // Callback can either be a function or a string
+      if (typeof callback !== 'function') {
+        callback = new Function('' + callback) as Callback;
+      }
+      // Store and register the task
+      const task = { callback: callback, args: args };
+      tasksByHandle[nextHandle] = task;
+      registerImmediate(nextHandle);
+      return nextHandle++;
+    }
+
+    function clearImmediate(handle: number) {
+        delete tasksByHandle[handle];
+    }
+
+    function run(task: Task) {
+        const callback = task.callback;
+        const args = task.args;
+        switch (args.length) {
+        case 0:
+            callback();
+            break;
+        case 1:
+            callback(args[0]);
+            break;
+        case 2:
+            callback(args[0], args[1]);
+            break;
+        case 3:
+            callback(args[0], args[1], args[2]);
+            break;
+        default:
+            callback.apply(undefined, args);
+            break;
+        }
+    }
+
+    function runIfPresent(handle: number) {
+        // From the spec: 'Wait until any invocations of this algorithm started before this one have completed.'
+        // So if we're currently running a task, we'll need to delay this invocation.
+        if (currentlyRunningATask) {
+            // Delay by doing a setTimeout. setImmediate was tried instead, but in Firefox 7 it generated a
+            // 'too much recursion' error.
+            setTimeout(runIfPresent, 0, handle);
+        } else {
+            const task = tasksByHandle[handle];
+            if (task) {
+                currentlyRunningATask = true;
+                try {
+                    run(task);
+                } finally {
+                    clearImmediate(handle);
+                    currentlyRunningATask = false;
+                }
+            }
+        }
+    }
+
+    function installNextTickImplementation() {
+        registerImmediate = function(handle) {
+            process.nextTick(function () { runIfPresent(handle); });
+        };
+    }
+
+    function canUsePostMessage() {
+        // The test against `importScripts` prevents this implementation from being installed inside a web worker,
+        // where `global.postMessage` means something completely different and can't be used for this purpose.
+        const global = typeof window !== 'undefined' ? window as any : void 0;
+        if (global && global.postMessage && !global.importScripts) {
+            let postMessageIsAsynchronous = true;
+            const oldOnMessage = global.onmessage;
+            global.onmessage = function() {
+                postMessageIsAsynchronous = false;
+            };
+            global.postMessage('', '*');
+            global.onmessage = oldOnMessage;
+            return postMessageIsAsynchronous;
+        }
+    }
+
+    function installPostMessageImplementation() {
+        // Installs an event handler on `global` for the `message` event: see
+        // * https://developer.mozilla.org/en/DOM/window.postMessage
+        // * http://www.whatwg.org/specs/web-apps/current-work/multipage/comms.html#crossDocumentMessages
+
+        const messagePrefix = 'setImmediate$' + Math.random() + '$';
+        const global = typeof window !== 'undefined' ? window as any : void 0;
+        const onGlobalMessage = function(event: any) {
+            if (event.source === global &&
+                typeof event.data === 'string' &&
+                event.data.indexOf(messagePrefix) === 0) {
+                runIfPresent(+event.data.slice(messagePrefix.length));
+            }
+        };
+
+        if (window.addEventListener) {
+            window.addEventListener('message', onGlobalMessage, false);
+        } else {
+            (window as any).attachEvent('onmessage', onGlobalMessage);
+        }
+
+        registerImmediate = function(handle) {
+            window.postMessage(messagePrefix + handle, '*');
+        };
+    }
+
+    function installMessageChannelImplementation() {
+        const channel = new MessageChannel();
+        channel.port1.onmessage = function(event) {
+            const handle = event.data;
+            runIfPresent(handle);
+        };
+
+        registerImmediate = function(handle) {
+            channel.port2.postMessage(handle);
+        };
+    }
+
+    function installReadyStateChangeImplementation() {
+        const html = doc!.documentElement;
+        registerImmediate = function(handle) {
+            // Create a <script> element; its readystatechange event will be fired asynchronously once it is inserted
+            // into the document. Do so, thus queuing up the task. Remember to clean up once it's been called.
+            let script = doc!.createElement('script') as any;
+            script.onreadystatechange = function () {
+                runIfPresent(handle);
+                script.onreadystatechange = null;
+                html.removeChild(script);
+                script = null;
+            };
+            html.appendChild(script);
+        };
+    }
+
+    function installSetTimeoutImplementation() {
+        registerImmediate = function(handle) {
+            setTimeout(runIfPresent, 0, handle);
+        };
+    }
+
+    // Don't get fooled by e.g. browserify environments.
+    if (typeof process !== 'undefined' && {}.toString.call(process) === '[object process]') {
+        // For Node.js before 0.9
+        installNextTickImplementation();
+    } else if (canUsePostMessage()) {
+        // For non-IE10 modern browsers
+        installPostMessageImplementation();
+    } else if (typeof MessageChannel !== 'undefined') {
+        // For web workers, where supported
+        installMessageChannelImplementation();
+    } else if (doc && 'onreadystatechange' in doc.createElement('script')) {
+        // For IE 6–8
+        installReadyStateChangeImplementation();
+    } else {
+        // For older browsers
+        installSetTimeoutImplementation();
+    }
+
+    return {
+        setImmediate,
+        clearImmediate
+    };
+}
+
+const immediateActions = (function () {
+    if (typeof setImmediate !== 'undefined') {
+        if (typeof window !== 'undefined') {
+            return { setImmediate: (handler: any, ...args: any[]) => window.setImmediate(handler, ...args as any), clearImmediate: (handle: any) => window.clearImmediate(handle) };
+        } else return { setImmediate, clearImmediate }
+    }
+    return createImmediateActions();
+}());
+
+function resolveImmediate(res: () => void) {
+    immediateActions.setImmediate(res);
+}
+
+export default {
+    immediate: immediateActions.setImmediate,
+    clearImmediate: immediateActions.clearImmediate,
+
+    immediatePromise() { return new Promise<void>(resolveImmediate); }
+};

src/mol-task/execution/observable.ts

+/**
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+import Task from '../task'
+import RuntimeContext from './runtime-context'
+
+interface Progress {
+    taskId: number,
+    elapsedMs: { real: number, cpu: number },
+    tree: Progress.Node,
+    tryAbort?: () => void
+}
+
+namespace Progress {
+    export interface Node {
+        readonly progress: Task.Progress,
+        readonly children: ReadonlyArray<Node>
+    }
+
+    export interface Observer { (progress: Progress): void }
+}
+
+class ObservableExecutor {
+    async run<T>(task: Task<T>): Promise<T> {
+        const ctx = new ObservableRuntimeContext();
+        if (!task.__onAbort) return task.__f(ctx);
+
+        try {
+            return await task.__f(ctx);
+        } catch (e) {
+            if (e === Task.Aborted) task.__onAbort();
+            throw e;
+        }
+    }
+
+    constructor(observer: Progress.Observer, updateRateMs: number) {
+
+    }
+}
+
+class ObservableRuntimeContext implements RuntimeContext {
+    id: number = 0;
+    requiresUpdate: boolean = false;
+    update(progress: Partial<RuntimeContext.ProgressUpdate>): Promise<void> { 
+        return 0 as any;
+    }
+    runChild<T>(progress: Partial<RuntimeContext.ProgressUpdate>, task: Task<T>): Promise<T> {
+        return 0 as any;
+    }
+}
+
+function ExecuteObservable<T>(task: Task<T>, observer: Progress.Observer, updateRateMs = 250) {
+    return new ObservableExecutor(observer, updateRateMs).run(task);
+}
+
+namespace ExecuteObservable {
+    export let PRINT_ERRORS_TO_CONSOLE = false;
+}
+
+export { ExecuteObservable, Progress }
\ No newline at end of file

src/mol-task/execution/runtime-context.ts

+/**
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+import Task from '../task'
+
+interface RuntimeContext {
+    readonly requiresUpdate: boolean,
+    // Idiomatic usage:
+    // if (ctx.requiresUpdate) await ctx.update({ ... });
+    update(progress: Partial<RuntimeContext.ProgressUpdate>): Promise<void>,
+    // Force the user to pass the progress so that the progress tree can be kept in a "good state".
+    runChild<T>(progress: Partial<RuntimeContext.ProgressUpdate>, task: Task<T>): Promise<T>
+}
+
+namespace RuntimeContext {
+    export interface AbortToken { isAborted: boolean }
+
+    export interface ProgressUpdate {
+        message: string,
+        isIndeterminate: boolean,
+        current: number,
+        max: number,
+        canAbort: boolean
+    }
+}
+
+export default RuntimeContext
\ No newline at end of file

src/mol-task/execution/synchronous.ts

+/**
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+import Task from '../task'
+import RuntimeContext from './runtime-context'
+
+const voidPromise = Promise.resolve(void 0);
+
+class SynchronousRuntimeContext implements RuntimeContext {
+    id: number = 0;
+    requiresUpdate: boolean = false;
+    update(progress: Partial<RuntimeContext.ProgressUpdate>): Promise<void> { return voidPromise; }
+    runChild<T>(progress: Partial<RuntimeContext.ProgressUpdate>, task: Task<T>): Promise<T> { return ExecuteSynchronous(task); }
+}
+
+const SyncRuntimeInstance = new SynchronousRuntimeContext();
+
+function ExecuteSynchronous<T>(task: Task<T>) {
+    return task.__f(SyncRuntimeInstance);
+}
+
+export default ExecuteSynchronous
\ No newline at end of file

src/mol-task/index.ts

+/**
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+import Task from './task'
+import RuntimeContext from './execution/runtime-context'
+import ExecuteSynchronous from './execution/synchronous'
+
+export { Task, RuntimeContext, ExecuteSynchronous }
\ No newline at end of file

src/mol-task/task.ts

+/**
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+import RuntimeContext from './execution/runtime-context'
+
+interface Task<T> {
+    readonly id: number,
+    readonly name: string,
+    readonly __f: (ctx: RuntimeContext) => Promise<T>,
+    readonly __onAbort: (() => void) | undefined
+}
+
+namespace Task {
+    export const Aborted = 'Aborted.';
+
+    export function create<T>(name: string, f: (ctx: RuntimeContext) => Promise<T>, onAbort?: () => void): Task<T> {
+        return { id: nextId(), name, __f: f, __onAbort: onAbort };
+    }
+
+    export function constant<T>(name: string, value: T): Task<T> { return create(name, async ctx => value); }
+    export function fail(name: string, reason: string): Task<any> { return create(name, async ctx => { throw new Error(reason); }); }
+
+    let _id = 0;
+    function nextId() {
+        const ret = _id;
+        _id = (_id + 1) % 0x3fffffff;
+        return ret;
+    }
+
+    export type Progress = IndeterminateProgress | DeterminateProgress
+
+    interface ProgressBase {
+        runtimeId: number,
+        taskId: number,
+        message: string,
+        elapsedMs: { real: number, cpu: number },
+        canAbort: boolean,
+        children?: Progress[]
+    }
+
+    export interface IndeterminateProgress extends ProgressBase { isIndeterminate: true }
+    export interface DeterminateProgress extends ProgressBase { isIndeterminate: false, current: number, max: number }
+
+    export interface State {
+        runtimeId: number,
+        taskId: number,
+
+        message: string,
+        elapsedMs: number,
+        canAbort: boolean,
+        isIndeterminate: boolean,
+        current: number,
+        max: number,
+        children?: State[]
+    }
+}
+
+export default Task
\ No newline at end of file

src/mol-task/util.ts

 
+// enum TaskState {
+//     Pending,
+//     Running,
+//     Aborted,
+//     Completed,
+//     Failed
+// }
 
+interface TaskState {
+
+}
+
+namespace TaskState {
+    export interface Pending { kind: 'Pending' }
+    export interface Running { kind: 'Running',  }
+
+    export interface Progress {
+        message: string,
+        isIndeterminate: boolean,
+        current: number,
+        max: number,
+        elapsedMs: number
+    }
+}
 
 type ExecutionContext = {
     run<T>(c: Computation<T>, params?: { updateRateMs: number }): Promise<T>,
-    subscribe(o: (p: string, compId: number) => void): void
+    subscribe(o: (p: string, compId: number) => void): void,
+
+    requestAbort(compId: number): void
 }
 
 namespace ExecutionContext {
@@ -17,12 +42,13 @@ namespace ExecutionContext {
     export const Sync: ExecutionContext = 0 as any;
 }
 
-interface RuntimeContext extends ExecutionContext {
+interface RuntimeContext {
+    run<T>(c: Computation<T>, params?: { updateRateMs: number }): Promise<T>,
     yield(name: string): Promise<void> | void
 }
 
 // if no context is specified, use the synchronous one.
-type Computation<T> = { (ctx?: RuntimeContext): Promise<T>, _id: number }
+interface Computation<T> { (ctx: RuntimeContext): Promise<T>, _id: number }
 
 function create<T>(c: (ctx: RuntimeContext) => Promise<T>): Computation<T> { return 0 as any; }
 function constant<T>(c: T) { return create(async ctx => c); }
@@ -58,7 +84,7 @@ function readLines(str: string): Computation<string[]> {
 
 const prependHiToLines = MultistepComputation('Hi prepend', ['Parse input', 'Prepend Hi'], async (p: string, step, ctx) => {
     await step(0);
-    const lines = await ctx.run(readLines(p));
+    const lines = await readLines(p)(ctx);
     await step(1);
     const ret = lines.map(l => 'Hi ' + l);
     return ret;

tsconfig.json

@@ -13,6 +13,7 @@
         "outDir": "build/node_modules",
         "baseUrl": "src",
         "paths": {
+            "mol-task": ["./mol-task", "./mol-task/index.ts"],
             "mol-comp": ["./mol-comp", "./mol-comp/index.ts"],
             "mol-util": ["./mol-util", "./mol-util/index.ts"],
             "mol-data": ["./mol-data", "./mol-data/index.ts"],