Enhance deeplink and single instance management for Windows

- Added functions to manage lock files and check if the primary instance is running, improving instance handling.
- Implemented retry logic for forwarding deeplinks via Windows pipes, enhancing reliability in communication between instances.
- Refactored existing functions to streamline the deeplink forwarding process and improve code clarity.

src/desktop/deeplink-ipc.js

@@ -11,7 +11,10 @@ import { join } from 'node:path'
 export const PROTOCOL_PREFIX = 'farmcontrol://'
 export const WINDOWS_PIPE_NAME = '\\\\.\\pipe\\com.tombutcher.farmcontrol.instance'
 export const SIGNAL_FILE = 'instance-signal.json'
+export const LOCK_FILE = 'primary.lock'
 const FORWARD_TIMEOUT_MS = 750
+const PIPE_RETRY_ATTEMPTS = 3
+const PIPE_RETRY_DELAY_MS = 100
 
 export function getInstanceDir() {
   if (process.platform === 'win32') {
@@ -28,6 +31,37 @@ export function getSignalPath() {
   return join(getInstanceDir(), SIGNAL_FILE)
 }
 
+export function getLockPath() {
+  return join(getInstanceDir(), LOCK_FILE)
+}
+
+export function isProcessAlive(pid) {
+  if (!Number.isInteger(pid) || pid <= 0) {
+    return false
+  }
+
+  try {
+    process.kill(pid, 0)
+    return true
+  } catch {
+    return false
+  }
+}
+
+export function isPrimaryInstanceRunning() {
+  const lockPath = getLockPath()
+  if (!existsSync(lockPath)) {
+    return false
+  }
+
+  try {
+    const existingPid = Number.parseInt(readFileSync(lockPath, 'utf8').trim(), 10)
+    return isProcessAlive(existingPid)
+  } catch {
+    return false
+  }
+}
+
 export function findProtocolUrl(args) {
   const directMatch = args.find(
     (arg) => typeof arg === 'string' && arg.startsWith(PROTOCOL_PREFIX)
@@ -117,7 +151,7 @@ export function writeDeeplinkSignal(payload) {
   unlinkSync(tempPath)
 }
 
-export function forwardDeeplinkToRunningInstance(payload) {
+function tryForwardViaPipe(payload) {
   return new Promise((resolve) => {
     let settled = false
     const finish = (forwarded) => {
@@ -126,7 +160,7 @@ export function forwardDeeplinkToRunningInstance(payload) {
       resolve(forwarded)
     }
 
-    const client = net.connect(WINDOWS_PIPE_NAME)
+    const client = net.connect({ path: WINDOWS_PIPE_NAME })
     const message = JSON.stringify(payload)
 
     client.on('connect', () => {
@@ -145,3 +179,38 @@ export function forwardDeeplinkToRunningInstance(payload) {
     })
   })
 }
+
+function delay(ms) {
+  return new Promise((resolve) => {
+    setTimeout(resolve, ms)
+  })
+}
+
+async function tryForwardViaPipeWithRetries(payload) {
+  for (let attempt = 0; attempt < PIPE_RETRY_ATTEMPTS; attempt += 1) {
+    if (await tryForwardViaPipe(payload)) {
+      return true
+    }
+
+    if (attempt < PIPE_RETRY_ATTEMPTS - 1) {
+      await delay(PIPE_RETRY_DELAY_MS)
+    }
+  }
+
+  return false
+}
+
+export async function forwardDeeplinkToRunningInstance(payload) {
+  if (process.platform === 'win32') {
+    if (await tryForwardViaPipeWithRetries(payload)) {
+      return true
+    }
+  }
+
+  if (isPrimaryInstanceRunning()) {
+    writeDeeplinkSignal(payload)
+    return true
+  }
+
+  return false
+}

src/desktop/single-instance.js

@@ -9,20 +9,19 @@ import {
   writeFileSync
 } from 'node:fs'
 import net from 'node:net'
-import { join } from 'node:path'
 import {
   buildDeeplinkPayload,
   findProtocolUrl,
   forwardDeeplinkToRunningInstance,
   getInstanceDir,
+  getLockPath,
   getSignalPath,
+  isProcessAlive,
   SIGNAL_FILE,
   WINDOWS_PIPE_NAME,
   writeDeeplinkSignal
 } from './deeplink-ipc.js'
 
-const LOCK_FILE = 'primary.lock'
-
 let lockFd = null
 let pollInterval = null
 let fsWatcher = null
@@ -33,23 +32,6 @@ let handlers = {
 }
 const pendingMessages = []
 
-function getLockPath() {
-  return join(getInstanceDir(), LOCK_FILE)
-}
-
-function isProcessAlive(pid) {
-  if (!Number.isInteger(pid) || pid <= 0) {
-    return false
-  }
-
-  try {
-    process.kill(pid, 0)
-    return true
-  } catch {
-    return false
-  }
-}
-
 function tryAcquirePrimaryLock() {
   mkdirSync(getInstanceDir(), { recursive: true })
   const lockPath = getLockPath()
@@ -247,7 +229,7 @@ function startWindowsPipeServer() {
     }
   })
 
-  server.listen(WINDOWS_PIPE_NAME)
+  server.listen({ path: WINDOWS_PIPE_NAME })
   pipeServer = server
 }
 
@@ -274,6 +256,7 @@ export async function ensureSingleInstanceLock({ launchUrl } = {}) {
     }
 
     startWindowsPipeServer()
+    startInstanceSignalWatcher()
     return true
   }