fix(core): proper exit cleanup in json file

packages/core/package.json

@@ -15,6 +15,7 @@
         "./src/utils/platform/transport.js": "./src/utils/platform/transport.web.js",
         "./src/utils/platform/logging.js": "./src/utils/platform/logging.web.js",
         "./src/utils/platform/random.js": "./src/utils/platform/random.web.js",
+        "./src/utils/platform/exit-hook.js": "./src/utils/platform/exit-hook.web.js",
         "./src/storage/json-file.js": false
     },
     "distOnlyFields": {

packages/core/src/storage/json-file.ts

@@ -1,10 +1,9 @@
 // eslint-disable-next-line no-restricted-imports
 import * as fs from 'fs'
 
+import { beforeExit } from '../utils/index.js'
 import { JsonMemoryStorage } from './json.js'
 
-const EVENTS = ['exit', 'SIGINT', 'SIGUSR1', 'SIGUSR2', 'uncaughtException', 'SIGTERM']
-
 /**
  * mtcute storage that stores data in a JSON file.
  *
@@ -20,7 +19,7 @@ const EVENTS = ['exit', 'SIGINT', 'SIGUSR1', 'SIGUSR2', 'uncaughtException', 'SI
 export class JsonFileStorage extends JsonMemoryStorage {
     private readonly _filename: string
     private readonly _safe: boolean
-    private readonly _cleanup: boolean
+    private readonly _cleanupUnregister?: () => void
 
     constructor(
         filename: string,
@@ -50,11 +49,9 @@ export class JsonFileStorage extends JsonMemoryStorage {
 
         this._filename = filename
         this._safe = params?.safe ?? true
-        this._cleanup = params?.cleanup ?? true
 
-        if (this._cleanup) {
+        if (params?.cleanup !== false) {
-            this._onProcessExit = this._onProcessExit.bind(this)
+            this._cleanupUnregister = beforeExit(() => this._onProcessExit())
-            EVENTS.forEach((event) => process.on(event, this._onProcessExit))
         }
     }
 
@@ -82,12 +79,8 @@ export class JsonFileStorage extends JsonMemoryStorage {
         })
     }
 
-    private _processExitHandled = false
     private _onProcessExit(): void {
         // on exit handler must be synchronous, thus we use sync methods here
-        if (this._processExitHandled) return
-        this._processExitHandled = true
-
         try {
             fs.writeFileSync(this._filename, this._saveJson())
         } catch (e) {}
@@ -100,8 +93,6 @@ export class JsonFileStorage extends JsonMemoryStorage {
     }
 
     destroy(): void {
-        if (this._cleanup) {
+        this._cleanupUnregister?.()
-            EVENTS.forEach((event) => process.off(event, this._onProcessExit))
-        }
     }
 }

packages/core/src/utils/index.ts

@@ -16,6 +16,7 @@ export * from './lru-map.js'
 export * from './lru-set.js'
 export * from './misc-utils.js'
 export * from './peer-utils.js'
+export * from './platform/exit-hook.js'
 export * from './sorted-array.js'
 export * from './string-session.js'
 export * from './tl-json.js'

packages/core/src/utils/platform/exit-hook.ts

@@ -0,0 +1,53 @@
+// roughly based on https://github.com/sindresorhus/exit-hook/blob/main/index.js, MIT license
+
+let installed = false
+let handled = false
+
+const callbacks = new Set<() => void>()
+
+function exit(shouldManuallyExit: boolean, signal: number, event: string) {
+    return function eventHandler() {
+        if (handled) {
+            return
+        }
+
+        handled = true
+
+        const exitCode = 128 + signal
+
+        for (const callback of callbacks) {
+            callback()
+        }
+
+        if (shouldManuallyExit) {
+            // if the user has some custom handlers after us, we don't want to exit the process
+
+            const listeners = process.rawListeners(event)
+            const idx = listeners.indexOf(eventHandler)
+
+            if (idx === listeners.length - 1) {
+                process.exit(exitCode)
+            }
+        }
+    }
+}
+
+export function beforeExit(fn: () => void): () => void {
+    // unsupported platform
+    if (typeof process === 'undefined') return () => {}
+
+    if (!installed) {
+        installed = true
+
+        process.on('beforeExit', exit(true, -128, 'beforeExit'))
+        process.on('SIGINT', exit(true, 2, 'SIGINT'))
+        process.on('SIGTERM', exit(true, 15, 'SIGINT'))
+        process.on('exit', exit(false, 15, 'exit'))
+    }
+
+    callbacks.add(fn)
+
+    return () => {
+        callbacks.delete(fn)
+    }
+}

packages/core/src/utils/platform/exit-hook.web.ts

@@ -0,0 +1,21 @@
+const callbacks = new Set<() => void>()
+
+let registered = false
+
+export function beforeExit(fn: () => void): () => void {
+    if (!registered) {
+        registered = true
+
+        window.addEventListener('beforeunload', () => {
+            for (const callback of callbacks) {
+                callback()
+            }
+        })
+    }
+
+    callbacks.add(fn)
+
+    return () => {
+        callbacks.delete(fn)
+    }
+}