dynamic-function-registry.ts

import {IFunctionDefinition} from "./function-defintion";
import {SimpleMap} from "../util/simple-map";
import {IFunctionId, functionId, isFunctionId} from "./function-id";
import {getFunctionName} from "../util/function-name";

/**
 * Lookup table for resolving dynamic functions and their definitions
 */
export class DynamicFunctionRegistry {
    private ids = new SimpleMap<string, IFunctionId>();
    private definitions = new SimpleMap<string, IFunctionDefinition>();
    private lastId = 0;

    /**
     * Returns the unique id for the passed in function or assigns a new id to the given function and returns the newly assigned id
     * @param func the function for which the unique id should be determined
     * @returns  the id of this function
     */
    public getOrSetId(func: Function | IFunctionId): IFunctionId {
        if (isFunctionId(func)) {
            return func;
        }

        const source = func.toString();
        let identifier = this.ids.get(source);

        if (typeof (identifier) === "undefined") {
            identifier = functionId("dynamic", ++this.lastId);
            this.initDefinition(func, identifier);
        }

        return identifier;
    }

    /**
     * Returns the definition of the function with the given id or undefined, if the id is not assigned to any function definition
     * @param id the id of the function to resolve
     * @returns the resolved function definition or undefined
     * @throws if the function is a static function and therefore no definition exists.
     */
    public getDefinition(id: IFunctionId): IFunctionDefinition | undefined {
        return this.definitions.get(id.identifier);
    }

    private initDefinition(func: Function, id: IFunctionId) {
        const source = func.toString();
        const name = getFunctionName(func);
        const args = source.substring(source.indexOf("(") + 1, source.indexOf(")")).split(",");
        const body = source.substring(source.indexOf("{") + 1, source.lastIndexOf("}")).trim();

        const definition = {
            argumentNames: args.map(arg => arg.trim()),
            body,
            id,
            name: name ? name : undefined
        };

        this.ids.set(source, id);
        this.definitions.set(id.identifier, definition);
    }
}