diff options
Diffstat (limited to 'lang/gjs/lib/variable.ts')
| -rw-r--r-- | lang/gjs/lib/variable.ts | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/lang/gjs/lib/variable.ts b/lang/gjs/lib/variable.ts new file mode 100644 index 0000000..9b3d3d2 --- /dev/null +++ b/lang/gjs/lib/variable.ts @@ -0,0 +1,230 @@ +import Astal from "gi://AstalIO" +import Binding, { type Connectable, type Subscribable } from "./binding.js" +import { interval } from "./time.js" +import { execAsync, subprocess } from "./process.js" + +class VariableWrapper<T> extends Function { + private variable!: Astal.VariableBase + private errHandler? = console.error + + private _value: T + private _poll?: Astal.Time + private _watch?: Astal.Process + + private pollInterval = 1000 + private pollExec?: string[] | string + private pollTransform?: (stdout: string, prev: T) => T + private pollFn?: (prev: T) => T | Promise<T> + + private watchTransform?: (stdout: string, prev: T) => T + private watchExec?: string[] | string + + constructor(init: T) { + super() + this._value = init + this.variable = new Astal.VariableBase() + this.variable.connect("dropped", () => { + this.stopWatch() + this.stopPoll() + }) + this.variable.connect("error", (_, err) => this.errHandler?.(err)) + return new Proxy(this, { + apply: (target, _, args) => target._call(args[0]), + }) + } + + private _call<R = T>(transform?: (value: T) => R): Binding<R> { + const b = Binding.bind(this) + return transform ? b.as(transform) : b as unknown as Binding<R> + } + + toString() { + return String(`Variable<${this.get()}>`) + } + + get(): T { return this._value } + set(value: T) { + if (value !== this._value) { + this._value = value + this.variable.emit("changed") + } + } + + startPoll() { + if (this._poll) + return + + if (this.pollFn) { + this._poll = interval(this.pollInterval, () => { + const v = this.pollFn!(this.get()) + if (v instanceof Promise) { + v.then(v => this.set(v)) + .catch(err => this.variable.emit("error", err)) + } + else { + this.set(v) + } + }) + } + else if (this.pollExec) { + this._poll = interval(this.pollInterval, () => { + execAsync(this.pollExec!) + .then(v => this.set(this.pollTransform!(v, this.get()))) + .catch(err => this.variable.emit("error", err)) + }) + } + } + + startWatch() { + if (this._watch) + return + + this._watch = subprocess({ + cmd: this.watchExec!, + out: out => this.set(this.watchTransform!(out, this.get())), + err: err => this.variable.emit("error", err), + }) + } + + stopPoll() { + this._poll?.cancel() + delete this._poll + } + + stopWatch() { + this._watch?.kill() + delete this._watch + } + + isPolling() { return !!this._poll } + isWatching() { return !!this._watch } + + drop() { + this.variable.emit("dropped") + } + + onDropped(callback: () => void) { + this.variable.connect("dropped", callback) + return this as unknown as Variable<T> + } + + onError(callback: (err: string) => void) { + delete this.errHandler + this.variable.connect("error", (_, err) => callback(err)) + return this as unknown as Variable<T> + } + + subscribe(callback: (value: T) => void) { + const id = this.variable.connect("changed", () => { + callback(this.get()) + }) + return () => this.variable.disconnect(id) + } + + poll( + interval: number, + exec: string | string[], + transform?: (stdout: string, prev: T) => T + ): Variable<T> + + poll( + interval: number, + callback: (prev: T) => T | Promise<T> + ): Variable<T> + + poll( + interval: number, + exec: string | string[] | ((prev: T) => T | Promise<T>), + transform: (stdout: string, prev: T) => T = out => out as T, + ) { + this.stopPoll() + this.pollInterval = interval + this.pollTransform = transform + if (typeof exec === "function") { + this.pollFn = exec + delete this.pollExec + } + else { + this.pollExec = exec + delete this.pollFn + } + this.startPoll() + return this as unknown as Variable<T> + } + + watch( + exec: string | string[], + transform: (stdout: string, prev: T) => T = out => out as T, + ) { + this.stopWatch() + this.watchExec = exec + this.watchTransform = transform + this.startWatch() + return this as unknown as Variable<T> + } + + observe( + objs: Array<[obj: Connectable, signal: string]>, + callback: (...args: any[]) => T, + ): Variable<T> + + observe( + obj: Connectable, + signal: string, + callback: (...args: any[]) => T, + ): Variable<T> + + observe( + objs: Connectable | Array<[obj: Connectable, signal: string]>, + sigOrFn: string | ((obj: Connectable, ...args: any[]) => T), + callback?: (obj: Connectable, ...args: any[]) => T, + ) { + const f = typeof sigOrFn === "function" ? sigOrFn : callback ?? (() => this.get()) + const set = (obj: Connectable, ...args: any[]) => this.set(f(obj, ...args)) + + if (Array.isArray(objs)) { + for (const obj of objs) { + const [o, s] = obj + const id = o.connect(s, set) + this.onDropped(() => o.disconnect(id)) + } + } + else { + if (typeof sigOrFn === "string") { + const id = objs.connect(sigOrFn, set) + this.onDropped(() => objs.disconnect(id)) + } + } + + return this as unknown as Variable<T> + } + + static derive< + const Deps extends Array<Subscribable<any>>, + Args extends { + [K in keyof Deps]: Deps[K] extends Subscribable<infer T> ? T : never + }, + V = Args, + >(deps: Deps, fn: (...args: Args) => V = (...args) => args as unknown as V) { + const update = () => fn(...deps.map(d => d.get()) as Args) + const derived = new Variable(update()) + const unsubs = deps.map(dep => dep.subscribe(() => derived.set(update()))) + derived.onDropped(() => unsubs.map(unsub => unsub())) + return derived + } +} + +export interface Variable<T> extends Omit<VariableWrapper<T>, "bind"> { + <R>(transform: (value: T) => R): Binding<R> + (): Binding<T> +} + +export const Variable = new Proxy(VariableWrapper as any, { + apply: (_t, _a, args) => new VariableWrapper(args[0]), +}) as { + derive: typeof VariableWrapper["derive"] + <T>(init: T): Variable<T> + new<T>(init: T): Variable<T> +} + +export default Variable |