node-mpv-2/lib/ipcInterface/ipcRequest.js

A Node module for MPV

'use strict';

const ErrorHandler = require('../error');

// An object of this class is created for every message sent over the IPC socket
// via the ipcInterface. It stores information about what high level mpv function
// has invoked the message with which arguments
//
// Since every message is wrapped in a promise the resolve and reject functions
// are also stored in this object, such that it they can later be called
const ipcRequest = class {

	// constructs the object
	//
	// @param resolve - the resolve function of the message's promise
	// @param reject  - the reject  function of the message's promise
	// @param args    - arguments for the mpv command
	constructor (resolve, reject, args) {
		this.messageResolve = resolve;
		this.messageReject  = reject;
		this.args = args;

		// get the stack trace and look for the mpv function calls
		const stackMatch  = new Error().stack.match(/mpv.\w+\s/g);
		// get the last mpv function as the relevant caller for error handling
		this.caller = stackMatch ? stackMatch[stackMatch.length-1].slice(4, -1) + "()" : null;
	}

	// resolves the promise with the passed resolveValue
	//
	// @param resolveValue - the value passed to the promise resolve
	resolve(resolveValue){
		this.messageResolve(resolveValue);
	}

	// rejects the error with the passed rejectValue
	//
	// @param err - the error reason extracted from the IPC response
	reject(err){
		const errHandler = new ErrorHandler();
		const errMessage = errHandler.errorMessage(3, this.caller, this.args, err);
		this.messageReject(errMessage);
	}
}

module.exports = ipcRequest;