remote pty

app/lib/app.ts

@@ -5,13 +5,16 @@ import * as remote from '@electron/remote/main'
 import { loadConfig } from './config'
 import { Window, WindowOptions } from './window'
 import { pluginManager } from './pluginManager'
+import { PTYManager } from './pty'
 
 export class Application {
     private tray?: Tray
+    private ptyManager = new PTYManager()
     private windows: Window[] = []
 
     constructor () {
         remote.initialize()
+        this.ptyManager.init(this)
 
         ipcMain.on('app:config-change', (_event, config) => {
             this.broadcast('host:config-change', config)

app/lib/bufferizedPTY.js

@@ -0,0 +1,57 @@
+/** @hidden */
+module.exports = function patchPTYModule (mod) {
+    const oldSpawn = mod.spawn
+    if (mod.patched) {
+        return
+    }
+    mod.patched = true
+    mod.spawn = (file, args, opt) => {
+        let terminal = oldSpawn(file, args, opt)
+        let timeout = null
+        let buffer = Buffer.from('')
+        let lastFlush = 0
+        let nextTimeout = 0
+
+        // Minimum prebuffering window (ms) if the input is non-stop flowing
+        const minWindow = 5
+
+        // Maximum buffering time (ms) until output must be flushed unconditionally
+        const maxWindow = 100
+
+        function flush () {
+            if (buffer.length) {
+                terminal.emit('data-buffered', buffer)
+            }
+            lastFlush = Date.now()
+            buffer = Buffer.from('')
+        }
+
+        function reschedule () {
+            if (timeout) {
+                clearTimeout(timeout)
+            }
+            nextTimeout = Date.now() + minWindow
+            timeout = setTimeout(() => {
+                timeout = null
+                flush()
+            }, minWindow)
+        }
+
+        terminal.on('data', data => {
+            if (typeof data === 'string') {
+                data = Buffer.from(data)
+            }
+            buffer = Buffer.concat([buffer, data])
+            if (Date.now() - lastFlush > maxWindow) {
+                // Taking too much time buffering, flush to keep things interactive
+                flush()
+            } else {
+                if (Date.now() > nextTimeout - maxWindow / 10) {
+                    // Extend the window if it's expiring
+                    reschedule()
+                }
+            }
+        })
+        return terminal
+    }
+}

app/lib/pty.ts

@@ -0,0 +1,144 @@
+import * as nodePTY from '@terminus-term/node-pty'
+import { v4 as uuidv4 } from 'uuid'
+import { ipcMain } from 'electron'
+import { Application } from './app'
+
+class PTYDataQueue {
+    private buffers: Buffer[] = []
+    private delta = 0
+    private maxChunk = 1024
+    private maxDelta = 1024 * 50
+    private flowPaused = false
+
+    constructor (private pty: nodePTY.IPty, private onData: (data: Buffer) => void) { }
+
+    push (data: Buffer) {
+        this.buffers.push(data)
+        this.maybeEmit()
+    }
+
+    ack (length: number) {
+        this.delta -= length
+        this.maybeEmit()
+    }
+
+    private maybeEmit () {
+        if (this.delta <= this.maxDelta && this.flowPaused) {
+            this.resume()
+            return
+        }
+        if (this.buffers.length > 0) {
+            if (this.delta > this.maxDelta && !this.flowPaused) {
+                this.pause()
+                return
+            }
+
+            const buffersToSend = []
+            let totalLength = 0
+            while (totalLength < this.maxChunk && this.buffers.length) {
+                totalLength += this.buffers[0].length
+                buffersToSend.push(this.buffers.shift())
+            }
+            let toSend = Buffer.concat(buffersToSend)
+            this.buffers.unshift(toSend.slice(this.maxChunk))
+            toSend = toSend.slice(0, this.maxChunk)
+            this.onData(toSend)
+            this.delta += toSend.length
+            this.buffers = []
+        }
+    }
+
+    private pause () {
+        this.pty.pause()
+        this.flowPaused = true
+    }
+
+    private resume () {
+        this.pty.resume()
+        this.flowPaused = false
+        this.maybeEmit()
+    }
+}
+
+export class PTY {
+    private pty: nodePTY.IPty
+    private outputQueue: PTYDataQueue
+
+    constructor (private id: string, private app: Application, ...args: any[]) {
+        this.pty = (nodePTY as any).spawn(...args)
+        for (const key of ['close', 'exit']) {
+            (this.pty as any).on(key, (...eventArgs) => this.emit(key, ...eventArgs))
+        }
+
+        this.outputQueue = new PTYDataQueue(this.pty, data => {
+            setImmediate(() => this.emit('data-buffered', data))
+        })
+
+        this.pty.on('data', data => this.outputQueue.push(Buffer.from(data)))
+    }
+
+    getPID (): number {
+        return this.pty.pid
+    }
+
+    resize (columns: number, rows: number): void {
+        if ((this.pty as any)._writable) {
+            this.pty.resize(columns, rows)
+        }
+    }
+
+    write (buffer: Buffer): void {
+        if ((this.pty as any)._writable) {
+            this.pty.write(buffer.toString())
+        }
+    }
+
+    ackData (length: number): void {
+        this.outputQueue.ack(length)
+    }
+
+    kill (signal?: string): void {
+        this.pty.kill(signal)
+    }
+
+    private emit (event: string, ...args: any[]) {
+        this.app.broadcast(`pty:${this.id}:${event}`, ...args)
+    }
+}
+
+export class PTYManager {
+    private ptys: Record<string, PTY> = {}
+
+    init (app: Application): void {
+        //require('./bufferizedPTY')(nodePTY) // eslint-disable-line @typescript-eslint/no-var-requires
+        ipcMain.on('pty:spawn', (event, ...options) => {
+            const id = uuidv4().toString()
+            event.returnValue = id
+            this.ptys[id] = new PTY(id, app, ...options)
+        })
+
+        ipcMain.on('pty:exists', (event, id) => {
+            event.returnValue = !!this.ptys[id]
+        })
+
+        ipcMain.on('pty:get-pid', (event, id) => {
+            event.returnValue = this.ptys[id].getPID()
+        })
+
+        ipcMain.on('pty:resize', (_event, id, columns, rows) => {
+            this.ptys[id].resize(columns, rows)
+        })
+
+        ipcMain.on('pty:write', (_event, id, data) => {
+            this.ptys[id].write(Buffer.from(data))
+        })
+
+        ipcMain.on('pty:kill', (_event, id, signal) => {
+            this.ptys[id].kill(signal)
+        })
+
+        ipcMain.on('pty:ack-data', (_event, id, length) => {
+            this.ptys[id].ackData(length)
+        })
+    }
+}