parallel.es/src/common/function/slave-function-lookup-table.ts

Simple parallelization for EcmaScript

import {IFunctionLookupTable} from "./function-lookup-table";
import {IFunctionDefinition} from "./function-defintion";
import {IFunctionId} from "./function-id";
import {SimpleMap} from "../util/simple-map";

/**
 * Cache used by each worker slave to cache the received functions.
 * Caching the functions has the advantage that function only is serialized, transmitted and deserialized once. This also
 * has the advantage, that the function instance stays the same and therefore can be optimized by the runtime system.
 */
export class SlaveFunctionLookupTable implements IFunctionLookupTable {
    private cache = new SimpleMap<string, Function>();

    /**
     * Resolves the funciton with the givne id
     * @param id the id of the function to resolve
     * @returns the resolved function or undefined if not known
     */
    public getFunction(id: IFunctionId): Function | undefined {
        return this.cache.get(id.identifier);
    }

    /**
     * Registers a new function in the cache
     * @param definition the definition of the function to register
     * @returns the registered function
     */
    public registerFunction(definition: IFunctionDefinition): Function {
        const f = Function.apply(null, [...definition.argumentNames, definition.body]);
        this.cache.set(definition.id.identifier, f);
        return f;
    }

    public registerStaticFunction(id: IFunctionId, func: Function): void {
        if (this.has(id)) {
            throw new Error(`The given function id '${id.identifier}' is already used by another function registration, the id needs to be unique.`);
        }
        this.cache.set(id.identifier, func);
    }

    /**
     * Tests if the cache contains a function with the given id
     * @param id the id of the function to test for existence
     * @returns true if the cache contains a function with the given id
     */
    public has(id: IFunctionId) {
        return this.cache.has(id.identifier);
    }
}