Chore: Refactor mobile plugin logic into locations more consistent with other parts of the app (#10636)

packages/app-mobile/components/plugins/backgroundPage/startStopPlugin.ts

@@ -0,0 +1,83 @@
+import RemoteMessenger from '@joplin/lib/utils/ipc/RemoteMessenger';
+import { PluginMainProcessApi, PluginWebViewApi } from '../types';
+import WebViewToRNMessenger from '../../../utils/ipc/WebViewToRNMessenger';
+import WindowMessenger from '@joplin/lib/utils/ipc/WindowMessenger';
+import makeSandboxedIframe from './utils/makeSandboxedIframe';
+
+type PluginRecord = {
+	iframe: HTMLIFrameElement;
+	connectionToParent: RemoteMessenger<PluginWebViewApi, PluginMainProcessApi>|null;
+	connectionToIframe: RemoteMessenger<PluginMainProcessApi, PluginWebViewApi>|null;
+};
+
+const loadedPlugins: Record<string, PluginRecord> = Object.create(null);
+
+export const stopPlugin = async (pluginId: string) => {
+	if (!loadedPlugins[pluginId]) {
+		return;
+	}
+
+	loadedPlugins[pluginId].connectionToIframe?.closeConnection?.();
+	loadedPlugins[pluginId].connectionToParent?.closeConnection?.();
+
+	const iframe = loadedPlugins[pluginId].iframe;
+	iframe.srcdoc = '';
+	iframe.remove();
+	delete loadedPlugins[pluginId];
+};
+
+export const runPlugin = (
+	pluginBackgroundScript: string, pluginScript: string, messageChannelId: string, pluginId: string,
+) => {
+	if (loadedPlugins[pluginId]) {
+		console.warn(`Plugin already running ${pluginId}`);
+		return;
+	}
+
+	const bodyHtml = '';
+	const initialJavaScript = `
+		"use strict";
+		${pluginBackgroundScript}
+
+		(async () => {
+			window.require = function(module) {
+				return pluginBackgroundPage.requireModule(module, ${JSON.stringify(pluginId)});
+			};
+			window.exports = window.exports || {};
+
+			await pluginBackgroundPage.initializePluginBackgroundIframe(${JSON.stringify(messageChannelId)});
+
+			${pluginScript}
+		})();
+	`;
+	const backgroundIframe = makeSandboxedIframe(bodyHtml, [initialJavaScript]).iframe;
+
+	loadedPlugins[pluginId] = {
+		iframe: backgroundIframe,
+		connectionToParent: null,
+		connectionToIframe: null,
+	};
+
+	backgroundIframe.addEventListener('load', async () => {
+		if (!loadedPlugins[pluginId]) {
+			return;
+		}
+
+		const connectionToParent = new WebViewToRNMessenger<PluginWebViewApi, PluginMainProcessApi>(messageChannelId, null);
+		const connectionToIframe = new WindowMessenger<PluginMainProcessApi, PluginWebViewApi>(
+			messageChannelId, backgroundIframe.contentWindow, connectionToParent.remoteApi,
+		);
+
+		// The two messengers are intermediate links in a chain (they serve to forward messages
+		// between the parent and the iframe).
+		connectionToParent.setIsChainedMessenger(true);
+		connectionToIframe.setIsChainedMessenger(true);
+
+		connectionToParent.setLocalInterface(connectionToIframe.remoteApi);
+
+		loadedPlugins[pluginId].connectionToIframe = connectionToIframe;
+		loadedPlugins[pluginId].connectionToParent = connectionToParent;
+	}, { once: true });
+
+	document.body.appendChild(backgroundIframe);
+};