From 57ec8ac9562be2766996befa6327514f11f4d8c3 Mon Sep 17 00:00:00 2001
From: a <a@a>
Date: Wed, 12 Aug 2020 00:20:46 +0200
Subject: [PATCH] Gtranslate queue

---
 src/background/background.ts         |  3 +-
 src/background/gtranslate_scraper.ts | 68 +++++++++++++++++++++-------
 2 files changed, 53 insertions(+), 18 deletions(-)

diff --git a/src/background/background.ts b/src/background/background.ts
index 27eba35..11d5733 100644
--- a/src/background/background.ts
+++ b/src/background/background.ts
@@ -7,7 +7,8 @@ import content_script from "../frontend/content_script/content_script.ts?file";
 let com = new Communicator();
 
 const scraper = new GTranslateScraper();
-com.translateCallback = (toTranslate) => scraper.translate(toTranslate);
+com.translateCallback = (toTranslate, sender) =>
+	scraper.translate(toTranslate, sender.tab?.id);
 
 const db = new Flashcards();
 com.addFlashcardCallback = (c) => db.addFlashcard(c);
diff --git a/src/background/gtranslate_scraper.ts b/src/background/gtranslate_scraper.ts
index 720a8ed..cb8bf25 100644
--- a/src/background/gtranslate_scraper.ts
+++ b/src/background/gtranslate_scraper.ts
@@ -1,23 +1,29 @@
 import { browser, WebRequest, Runtime } from "webextension-polyfill-ts";
 import content_script from "./gtranslate_content_script.ts?file";
 
+interface TranslationRequest {
+	tabID?: number;
+	resolveFn: (value: Translation) => void;
+	rejectFn: (reason: String) => void;
+	toTranslate: string;
+}
+
 export class GTranslateScraper {
-	iframe: HTMLIFrameElement;
-	conn?: Runtime.Port;
-	resolveFn?: (value: Translation) => void;
-	rejectFn?: (reason: String) => void;
+	private conn?: Runtime.Port;
+	private current?: TranslationRequest;
+	private queue: Array<TranslationRequest> = [];
 
 	constructor() {
 		browser.runtime.onConnect.addListener((p) => {
 			if (p.name != "gtranslate_scraper_conn") return;
 			this.conn = p;
+			this.processFromQueue(p);
 			p.onMessage.addListener((m) => this.onTranslationRecieved(m));
 		});
 
 		//This allows us to create the google translate iframe by removing the x-frame-options header
 		browser.webRequest.onHeadersReceived.addListener(
 			allowIFrameAccess,
-
 			{
 				urls: ["<all_urls>"],
 				types: ["sub_frame"],
@@ -28,7 +34,6 @@ export class GTranslateScraper {
 
 		//TODO make the language customizable
 		iframe.src = "https://translate.google.com/?op=translate&sl=de&tl=en";
-		this.iframe = iframe;
 
 		//Registers a temp content script, because we cannot inject scripts into iframes created on the background html page, because they have no tabId
 		const js = {
@@ -46,21 +51,50 @@ export class GTranslateScraper {
 				document.body.appendChild(iframe);
 			});
 	}
-	onTranslationRecieved(message: Translation) {
-		if (this.resolveFn) this.resolveFn(message);
-		this.resolveFn = undefined;
-		this.rejectFn = undefined;
+	private onTranslationRecieved(message: Translation) {
+		if (this.current) this.current.resolveFn(message);
+		this.current = undefined;
+		this.processFromQueue(this.conn!);
 	}
 
-	translate(to_translate: string): Promise<Translation> {
-		if (this.rejectFn) this.rejectFn("Got a different translation request");
-		if (!this.conn) return Promise.reject("The translator is not yet ready");
+	private processTranslationRequest(
+		request: TranslationRequest,
+		conn: Runtime.Port
+	) {
+		this.current = request;
+		conn.postMessage(request.toTranslate);
+	}
 
-		this.conn.postMessage(to_translate);
-		return new Promise((resolve, reject) => {
-			this.resolveFn = resolve;
-			this.rejectFn = reject;
+	private processFromQueue(conn: Runtime.Port) {
+		const next = this.queue.pop();
+		if (next) this.processTranslationRequest(next, conn);
+	}
+
+	translate(to_translate: string, tabID?: number): Promise<Translation> {
+		if (to_translate == "") return Promise.resolve({ src: "", result: "" });
+
+		const p = new Promise((resolve: (value: Translation) => void, reject) => {
+			const req = {
+				toTranslate: to_translate,
+				resolveFn: resolve,
+				rejectFn: reject,
+				tabID: tabID,
+			};
+			if (this.current || !this.conn) {
+				//Remove the requests from the same tab
+				if (tabID)
+					this.queue = this.queue.filter((r) => {
+						if (r.tabID !== tabID) {
+							r.rejectFn("Got another request from the same tab");
+							return true;
+						}
+					});
+				this.queue.push(req);
+			} else {
+				this.processTranslationRequest(req, this.conn);
+			}
 		});
+		return p;
 	}
 }