Program parallel downloader

src/update.js

@@ -1,6 +1,7 @@
 const path = require("node:path");
 const fs = require("node:fs");
 const crypto = require("node:crypto");
+const https = require("node:https");
 
 function checkFileAgainstSHA1(baseDirectory, fileEntry) {
 	return new Promise(function (resolve, reject) {
@@ -32,8 +33,68 @@ function checkFileAgainstSHA1(baseDirectory, fileEntry) {
 	});
 }
 
-module.exports = {
+function downloadFile(url, filePath) {
-	"checkFiles": function (manifest) {
+	return new Promise(function (resolve, reject) {
+		let fileOutputStream = fs.createWriteStream(filePath);
 
+		let request = https.request(url, {
+			"method": "GET"
+		}, function (response) {
+			if (response.statusCode !== 200) return reject(new Error("Got a non-OK response while trying to download a file."));
+
+			fileOutputStream.on("end", function () {
+				resolve(true);
+			});
+
+			response.pipe(fileOutputStream);
+		});
+
+		request.on("error", function (error) {
+			reject(error);
+		});
+
+		request.end();
+	});
+}
+
+function processDownloadQueue(baseDirectory, fileEntries) {
+	return new Promise(function (resolve, reject) {
+		let runningDownloads = 0;
+
+		for (let d = 0; d < module.exports.concurrentDownloads; d++) {
+
+		}
+	});
+}
+
+module.exports = {
+	"concurrentDownloads": 8,
+	"checkFiles": function (manifest, baseDirectory) {
+		return new Promise(function(resolve, reject) {
+			let checkTasks = [];
+
+			for (let f = 0; f < manifest.files.length; f++) {
+				let fileEntry = manifest.files[f];
+
+				checkTasks.push(checkFileAgainstSHA1(baseDirectory, fileEntry));
+			}
+
+			Promise.all(checkTasks).then(function (results) {
+				resolve(results);
+			}).catch(function (error) {
+				reject(error);
+			});
+		});
+	},
+	"downloadFiles": function (baseDirectory, fileEntries) {
+		return new Promise(function (resolve, reject) {
+			processDownloadQueue(baseDirectory, fileEntries.filter(function (entry) {
+				return !entry.ok;
+			})).then(function () {
+				resolve(true);
+			}).catch(function (error) {
+				reject(error);
+			});
+		});
 	}
 };