128 lines
3.4 KiB
TypeScript
128 lines
3.4 KiB
TypeScript
import { Feature, Manifest, RuntimeEnvironment } from "./types";
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import { EventEmitter } from "../common/event";
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import { Sandbox } from "./sandbox";
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import { Plug } from "./plug";
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interface SysCallMapping {
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[key: string]: (...args: any) => Promise<any> | any;
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}
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export type SystemJSON<HookT> = { [key: string]: Manifest<HookT> };
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export type SystemEvents<HookT> = {
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plugLoaded: (name: string, plug: Plug<HookT>) => void;
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plugUnloaded: (name: string, plug: Plug<HookT>) => void;
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};
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export class System<HookT> extends EventEmitter<SystemEvents<HookT>> {
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protected plugs = new Map<string, Plug<HookT>>();
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registeredSyscalls: SysCallMapping = {};
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protected enabledFeatures = new Set<Feature<HookT>>();
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readonly runtimeEnv: RuntimeEnvironment;
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constructor(env: RuntimeEnvironment) {
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super();
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this.runtimeEnv = env;
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}
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addFeature(feature: Feature<HookT>) {
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this.enabledFeatures.add(feature);
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feature.apply(this);
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}
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registerSyscalls(...registrationObjects: SysCallMapping[]) {
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for (const registrationObject of registrationObjects) {
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for (let p in registrationObject) {
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this.registeredSyscalls[p] = registrationObject[p];
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}
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}
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}
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async syscall(name: string, args: Array<any>): Promise<any> {
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const callback = this.registeredSyscalls[name];
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if (!name) {
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throw Error(`Unregistered syscall ${name}`);
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}
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if (!callback) {
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throw Error(`Registered but not implemented syscall ${name}`);
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}
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return Promise.resolve(callback(...args));
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}
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async load(
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name: string,
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manifest: Manifest<HookT>,
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sandbox: Sandbox
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): Promise<Plug<HookT>> {
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if (this.plugs.has(name)) {
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await this.unload(name);
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}
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// Validate
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let errors: string[] = [];
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for (const feature of this.enabledFeatures) {
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errors = [...errors, ...feature.validateManifest(manifest)];
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}
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if (errors.length > 0) {
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throw new Error(`Invalid manifest: ${errors.join(", ")}`);
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}
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// Ok, let's load this thing!
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const plug = new Plug(this, name, sandbox);
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await plug.load(manifest);
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this.plugs.set(name, plug);
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this.emit("plugLoaded", name, plug);
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return plug;
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}
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async unload(name: string) {
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const plug = this.plugs.get(name);
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if (!plug) {
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throw Error(`Plug ${name} not found`);
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}
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await plug.stop();
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this.emit("plugUnloaded", name, plug);
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this.plugs.delete(name);
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}
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async dispatchEvent(name: string, data?: any): Promise<any[]> {
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let promises = [];
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for (let plug of this.plugs.values()) {
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for (let result of await plug.dispatchEvent(name, data)) {
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promises.push(result);
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}
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}
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return await Promise.all(promises);
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}
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get loadedPlugs(): Map<string, Plug<HookT>> {
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return this.plugs;
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}
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toJSON(): SystemJSON<HookT> {
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let plugJSON: { [key: string]: Manifest<HookT> } = {};
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for (let [name, plug] of this.plugs) {
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if (!plug.manifest) {
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continue;
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}
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plugJSON[name] = plug.manifest;
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}
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return plugJSON;
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}
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async replaceAllFromJSON(
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json: SystemJSON<HookT>,
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sandboxFactory: () => Sandbox
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) {
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await this.unloadAll();
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for (let [name, manifest] of Object.entries(json)) {
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console.log("Loading plug", name);
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await this.load(name, manifest, sandboxFactory());
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}
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}
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async unloadAll(): Promise<void[]> {
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return Promise.all(
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Array.from(this.plugs.keys()).map(this.unload.bind(this))
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);
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}
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}
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