Started mol-comp

src/mol-comp/computation.ts

@@ -0,0 +1,283 @@
+/**
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * Adapted from https://github.com/dsehnal/LiteMol
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+import Scheduler from './scheduler'
+import timeNow from './time'
+
+interface Computation<A> {
+    (ctx?: Computation.Context): Promise<A>
+}
+
+namespace Computation {
+    export let PRINT_ERRORS_TO_CONSOLE = false;
+
+    export function create<A>(computation: (ctx: Context) => Promise<A>) {
+        return ComputationImpl(computation);
+    }
+
+    export function resolve<A>(a: A) {
+        return create<A>(_ => Promise.resolve(a));
+    }
+
+    export function reject<A>(reason: any) {
+        return create<A>(_ => Promise.reject(reason));
+    }
+
+    export interface Params {
+        updateRateMs?: number,
+        observer?: ProgressObserver
+    }
+
+    export const Aborted = 'Aborted';
+
+    export interface Progress {
+        message: string,
+        isIndeterminate: boolean,
+        current: number,
+        max: number,
+        elapsedMs: number,
+        requestAbort?: () => void
+    }
+
+    export interface ProgressUpdate {
+        message?: string,
+        abort?: boolean | (() => void),
+        current?: number,
+        max?: number
+    }
+
+    export interface Context {
+        readonly isSynchronous: boolean,
+        /** Also checks if the computation was aborted. If so, throws. */
+        readonly requiresUpdate: boolean,
+        requestAbort(): void,
+
+        subscribe(onProgress: ProgressObserver): { dispose: () => void },
+        /** Also checks if the computation was aborted. If so, throws. */
+        update(info: ProgressUpdate): Promise<void> | void
+    }
+
+    export type ProgressObserver = (progress: Readonly<Progress>) => void;
+
+    const emptyDisposer = { dispose: () => { } }
+
+    /** A context without updates. */
+    export const synchronous: Context = {
+        isSynchronous: true,
+        requiresUpdate: false,
+        requestAbort() { },
+        subscribe(onProgress) { return emptyDisposer; },
+        update(info) { }
+    }
+
+    export function observable(params?: Partial<Params>) {
+        const ret = new ObservableContext(params && params.updateRateMs);
+        if (params && params.observer) ret.subscribe(params.observer);
+        return ret;
+    }
+
+    export const now = timeNow;
+
+    /** A utility for splitting large computations into smaller parts. */
+    export interface Chunker {
+        setNextChunkSize(size: number): void,
+        /** nextChunk must return the number of actually processed chunks. */
+        process(nextChunk: (chunkSize: number) => number, update: (updater: Context['update']) => void, nextChunkSize?: number): Promise<void>
+    }
+
+    export function chunker(ctx: Context, nextChunkSize: number): Chunker {
+        return new ChunkerImpl(ctx, nextChunkSize);
+    }
+}
+
+const DefaulUpdateRateMs = 150;
+
+function ComputationImpl<A>(computation: (ctx: Computation.Context) => Promise<A>): Computation<A> {
+    return (ctx?: Computation.Context) => {
+        const context: ObservableContext = ctx ? ctx : Computation.synchronous as any;
+        return new Promise<A>(async (resolve, reject) => {
+            try {
+                if (context.started) context.started();
+                const result = await computation(context);
+                resolve(result);
+            } catch (e) {
+                if (Computation.PRINT_ERRORS_TO_CONSOLE) console.error(e);
+                reject(e);
+            } finally {
+                if (context.finished) context.finished();
+            }
+        });
+    }
+}
+
+class ObservableContext implements Computation.Context {
+    readonly updateRate: number;
+    readonly isSynchronous: boolean = false;
+    private level = 0;
+    private startedTime = 0;
+    private abortRequested = false;
+    private lastUpdated = 0;
+    private observers: Computation.ProgressObserver[] | undefined = void 0;
+    private progress: Computation.Progress = { message: 'Working...', current: 0, max: 0, elapsedMs: 0, isIndeterminate: true, requestAbort: void 0 };
+
+    private checkAborted() {
+        if (this.abortRequested) throw Computation.Aborted;
+    }
+
+    private abortRequester = () => { this.abortRequested = true };
+
+    subscribe = (obs: Computation.ProgressObserver) => {
+        if (!this.observers) this.observers = [];
+        this.observers.push(obs);
+        return {
+            dispose: () => {
+                if (!this.observers) return;
+                for (let i = 0; i < this.observers.length; i++) {
+                    if (this.observers[i] === obs) {
+                        this.observers[i] = this.observers[this.observers.length - 1];
+                        this.observers.pop();
+                        return;
+                    }
+                }
+            }
+        };
+    }
+
+    requestAbort() {
+        try {
+            if (this.abortRequester) {
+                this.abortRequester.call(null);
+            }
+        } catch (e) { }
+    }
+
+    update({ message, abort, current, max }: Computation.ProgressUpdate): Promise<void> | void {
+        this.checkAborted();
+
+        const time = Computation.now();
+
+        if (typeof abort === 'boolean') {
+            this.progress.requestAbort = abort ? this.abortRequester : void 0;
+        } else {
+            if (abort) this.abortRequester = abort;
+            this.progress.requestAbort = abort ? this.abortRequester : void 0;
+        }
+
+        if (typeof message !== 'undefined') this.progress.message = message;
+        this.progress.elapsedMs = time - this.startedTime;
+        if (isNaN(current!)) {
+            this.progress.isIndeterminate = true;
+        } else {
+            this.progress.isIndeterminate = false;
+            this.progress.current = current!;
+            if (!isNaN(max!)) this.progress.max = max!;
+        }
+
+        if (this.observers) {
+            const p = { ...this.progress };
+            for (let i = 0, _i = this.observers.length; i < _i; i++) {
+                Scheduler.immediate(this.observers[i], p);
+            }
+        }
+
+        this.lastUpdated = time;
+
+        return Scheduler.immediatePromise();
+    }
+
+    get requiresUpdate() {
+        this.checkAborted();
+        if (this.isSynchronous) return false;
+        return Computation.now() - this.lastUpdated > this.updateRate;
+    }
+
+    started() {
+        if (!this.level) {
+            this.startedTime = Computation.now();
+            this.lastUpdated = this.startedTime;
+        }
+        this.level++;
+    }
+
+    finished() {
+        this.level--;
+        if (this.level < 0) {
+            throw new Error('Bug in code somewhere, Computation.resolve/reject called too many times.');
+        }
+        if (!this.level) this.observers = void 0;
+    }
+
+    constructor(updateRate?: number) {
+        this.updateRate = updateRate || DefaulUpdateRateMs;
+    }
+}
+
+class ChunkerImpl implements Computation.Chunker {
+    private processedSinceUpdate = 0;
+    private updater: Computation.Context['update'];
+
+    private computeChunkSize(delta: number) {
+        if (!delta) {
+            this.processedSinceUpdate = 0;
+            return this.nextChunkSize;
+        }
+        const rate = (this.context as ObservableContext).updateRate || DefaulUpdateRateMs;
+        const ret = Math.round(this.processedSinceUpdate * rate / delta + 1);
+        this.processedSinceUpdate = 0;
+        return ret;
+    }
+
+    private getNextChunkSize() {
+        const ctx = this.context as ObservableContext;
+        // be smart if the computation is synchronous and process the whole chunk at once.
+        if (ctx.isSynchronous) return Number.MAX_SAFE_INTEGER;
+        return this.nextChunkSize;
+    }
+
+    setNextChunkSize(size: number) {
+        this.nextChunkSize = size;
+    }
+
+    async process(nextChunk: (size: number) => number, update: (updater: Computation.Context['update']) => Promise<void> | void, nextChunkSize?: number) {
+        if (typeof nextChunkSize !== 'undefined') this.setNextChunkSize(nextChunkSize);
+        this.processedSinceUpdate = 0;
+
+        // track time for the actual computation and exclude the "update time"
+        let chunkStart = Computation.now();
+        let lastChunkSize: number;
+        let chunkCount = 0;
+        let totalSize = 0;
+        let updateCount = 0;
+        while ((lastChunkSize = nextChunk(this.getNextChunkSize())) > 0) {
+            chunkCount++;
+            this.processedSinceUpdate += lastChunkSize;
+            totalSize += lastChunkSize;
+            if (this.context.requiresUpdate) {
+                let time = Computation.now();
+                await update(this.updater);
+                this.nextChunkSize = updateCount > 0
+                    ? Math.round((totalSize + this.computeChunkSize(time - chunkStart)) / (chunkCount + 1))
+                    : this.computeChunkSize(time - chunkStart)
+                updateCount++;
+                chunkStart = Computation.now();
+            }
+        }
+        if (this.context.requiresUpdate) {
+            let time = Computation.now();
+            await update(this.updater);
+            this.nextChunkSize = updateCount > 0
+                ? Math.round((totalSize + this.computeChunkSize(time - chunkStart)) / (chunkCount + 1))
+                : this.computeChunkSize(time - chunkStart)
+        }
+    }
+
+    constructor(public context: Computation.Context, private nextChunkSize: number) {
+        this.updater = this.context.update.bind(this.context);
+    }
+}
+
+export default Computation;

src/mol-comp/scheduler.ts

@@ -0,0 +1,207 @@
+/**
+ * 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-comp/time.ts

@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) 2017 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+declare var process: any;
+declare var window: any;
+
+const now: () => number = (function () {
+    if (typeof window !== 'undefined' && window.performance) {
+        const perf = window.performance;
+        return () => perf.now();
+    } else if (typeof process !== 'undefined' && process.hrtime !== 'undefined') {
+        return () => {
+            const t = process.hrtime();
+            return t[0] * 1000 + t[1] / 1000000;
+        };
+    } else {
+        return () => +new Date();
+    }
+}());
+
+export default now;

tsconfig.json

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