GM web hooks

Makes GM_xmlhttpRequest and GM_download queued

This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/460385/1221394/GM%20web%20hooks.js

/* eslint-disable no-multi-spaces */
/* eslint-disable no-native-reassign */
/* eslint-disable no-redeclare */

// ==UserScript==
// @name               GM web hooks
// @namespace          GM-web-hooks
// @version            0.1.2
// @description        Makes GM_xmlhttpRequest and GM_download queued
// @author             PY-DNG
// @license            GPL-v3
// ==/UserScript==

/* global LogLevel DoLog Err $ $All $CrE $AEL addStyle destroyEvent copyProp copyProps parseArgs escJsStr replaceText getUrlArgv dl_browser dl_GM AsyncManager */
/* global GM_xmlhttpRequest GM_download */

let [GMXHRHook, GMDLHook] = (function __MAIN__() {
    'use strict';

	return [GMXHRHook, GMDLHook];

	// GM_XHR HOOK: The number of running GM_XHRs in a time must under maxXHR
	// Returns the abort function to stop the request anyway(no matter it's still waiting, or requesting)
	// (If the request is invalid, such as url === '', will return false and will NOT make this request)
	// If the abort function called on a request that is not running(still waiting or finished), there will be NO onabort event
	// Requires: function delItem(){...} & function uniqueIDMaker(){...}
	function GMXHRHook(maxXHR=5) {
		const GM_XHR = GM_xmlhttpRequest;
		const getID = function() {
			let id = 0;
			return () => id++;
		}();
		let todoList = [], ongoingList = [];
		GM_xmlhttpRequest = safeGMxhr;

		function safeGMxhr() {
			// Get an id for this request, arrange a request object for it.
			const id = getID();
			const request = {id: id, args: arguments, aborter: null};

			// Deal onload function first
			dealEndingEvents(request);

			/* DO NOT DO THIS! KEEP ITS ORIGINAL PROPERTIES!
			// Stop invalid requests
			if (!validCheck(request)) {
				return false;
			}
			*/

			// Judge if we could start the request now or later?
			todoList.push(request);
			checkXHR();
			return makeAbortFunc(id);

			// Decrease activeXHRCount while GM_XHR onload;
			function dealEndingEvents(request) {
				const e = request.args[0];

				// onload event
				const oriOnload = e.onload;
				e.onload = function() {
					reqFinish(request.id);
					checkXHR();
					oriOnload ? oriOnload.apply(null, arguments) : function() {};
				}

				// onerror event
				const oriOnerror = e.onerror;
				e.onerror = function() {
					reqFinish(request.id);
					checkXHR();
					oriOnerror ? oriOnerror.apply(null, arguments) : function() {};
				}

				// ontimeout event
				const oriOntimeout = e.ontimeout;
				e.ontimeout = function() {
					reqFinish(request.id);
					checkXHR();
					oriOntimeout ? oriOntimeout.apply(null, arguments) : function() {};
				}

				// onabort event
				const oriOnabort = e.onabort;
				e.onabort = function() {
					reqFinish(request.id);
					checkXHR();
					oriOnabort ? oriOnabort.apply(null, arguments) : function() {};
				}
			}

			// Check if the request is invalid
			function validCheck(request) {
				const e = request.args[0];

				if (!e.url) {
					return false;
				}

				return true;
			}

			// Call a XHR from todoList and push the request object to ongoingList if called
			function checkXHR() {
				if (ongoingList.length >= maxXHR) {return false;};
				if (todoList.length === 0) {return false;};
				const req = todoList.shift();
				const reqArgs = req.args;
				const aborter = GM_XHR.apply(null, reqArgs);
				req.aborter = aborter;
				ongoingList.push(req);
				return req;
			}

			// Make a function that aborts a certain request
			function makeAbortFunc(id) {
				return function() {
					let i;

					// Check if the request haven't been called
					for (i = 0; i < todoList.length; i++) {
						const req = todoList[i];
						if (req.id === id) {
							// found this request: haven't been called
							todoList.splice(i, 1);
							return true;
						}
					}

					// Check if the request is running now
					for (i = 0; i < ongoingList.length; i++) {
						const req = todoList[i];
						if (req.id === id) {
							// found this request: running now
							req.aborter();
							reqFinish(id);
							checkXHR();
						}
					}

					// Oh no, this request is already finished...
					return false;
				}
			}

			// Remove a certain request from ongoingList
			function reqFinish(id) {
				let i;
				for (i = 0; i < ongoingList.length; i++) {
					const req = ongoingList[i];
					if (req.id === id) {
						ongoingList = ongoingList.splice(i, 1);
						return true;
					}
				}
				return false;
			}
		}
	}

	// GM_DL HOOK: The number of running GM_download in a time must under maxDL
	// Returns the abort function to stop the request anyway(no matter it's still waiting, or requesting)
	// (If the request is invalid, such as url === '', will return false and will NOT make this request)
	// If the abort function called on a request that is not running(still waiting or finished), there will be NO onabort event
	// Requires: function delItem(){...} & function uniqueIDMaker(){...}
	function GMDLHook(maxDL=5) {
		const GM_DL = GM_download;
		const getID = function() {
			let id = 0;
			return () => id++;
		}();
		let todoList = [], ongoingList = [];
		GM_download = safeGMdl;

		function safeGMdl() {
			// Get an id for this request, arrange a request object for it.
			const id = getID();
			const request = {id: id, args: arguments, aborter: null};

			// Deal onload function first
			dealEndingEvents(request);

			/* DO NOT DO THIS! KEEP ITS ORIGINAL PROPERTIES!
			// Stop invalid requests
			if (!validCheck(request)) {
				return false;
			}
			*/

			// Judge if we could start the request now or later?
			todoList.push(request);
			checkDL();
			return makeAbortFunc(id);

			// Decrease activeXHRCount while GM_DL onload;
			function dealEndingEvents(request) {
				const e = request.args[0];

				// onload event
				const oriOnload = e.onload;
				e.onload = function() {
					reqFinish(request.id);
					checkDL();
					oriOnload ? oriOnload.apply(null, arguments) : function() {};
				}

				// onerror event
				const oriOnerror = e.onerror;
				e.onerror = function() {
					reqFinish(request.id);
					checkDL();
					oriOnerror ? oriOnerror.apply(null, arguments) : function() {};
				}

				// ontimeout event
				const oriOntimeout = e.ontimeout;
				e.ontimeout = function() {
					reqFinish(request.id);
					checkDL();
					oriOntimeout ? oriOntimeout.apply(null, arguments) : function() {};
				}

				// onabort event
				const oriOnabort = e.onabort;
				e.onabort = function() {
					reqFinish(request.id);
					checkDL();
					oriOnabort ? oriOnabort.apply(null, arguments) : function() {};
				}
			}

			// Check if the request is invalid
			function validCheck(request) {
				const e = request.args[0];

				if (!e.url) {
					return false;
				}

				return true;
			}

			// Call a XHR from todoList and push the request object to ongoingList if called
			function checkDL() {
				if (ongoingList.length >= maxDL) {return false;};
				if (todoList.length === 0) {return false;};
				const req = todoList.shift();
				const reqArgs = req.args;
				const aborter = GM_DL.apply(null, reqArgs);
				req.aborter = aborter;
				ongoingList.push(req);
				return req;
			}

			// Make a function that aborts a certain request
			function makeAbortFunc(id) {
				return function() {
					let i;

					// Check if the request haven't been called
					for (i = 0; i < todoList.length; i++) {
						const req = todoList[i];
						if (req.id === id) {
							// found this request: haven't been called
							todoList.splice(i, 1);
							return true;
						}
					}

					// Check if the request is running now
					for (i = 0; i < ongoingList.length; i++) {
						const req = todoList[i];
						if (req.id === id) {
							// found this request: running now
							req.aborter();
							reqFinish(id);
							checkDL();
						}
					}

					// Oh no, this request is already finished...
					return false;
				}
			}

			// Remove a certain request from ongoingList
			function reqFinish(id) {
				let i;
				for (i = 0; i < ongoingList.length; i++) {
					const req = ongoingList[i];
					if (req.id === id) {
						ongoingList = ongoingList.splice(i, 1);
						return true;
					}
				}
				return false;
			}
		}
	}
})();