Android: Refactor tunnel engine

app-android/app/src/main/kotlin/com/algoritmico/passepartout/Globals.kt

@@ -15,8 +15,13 @@ object Globals {
     const val logTag = "Passepartout"
     const val serviceLogTag = "PassepartoutVpnService"
 
-    const val EVENT_BUFFER_CAPACITY = 64
+    // FIXME: Build bundle dynamically
+    const val BUNDLE_FILENAME = "bundle.json"
+    const val CONSTANTS_FILENAME = "constants.json"
+    const val PROFILES_DIRECTORY = "profiles-v1"
+    const val PROFILE_LAST_PATH = "tunnel_profile.json"
 
+    const val EVENT_BUFFER_CAPACITY = 64
     const val EVENT_REPLAY = 64
 }
 

app-android/app/src/main/kotlin/com/algoritmico/passepartout/PassepartoutVpnService.kt

@@ -1,102 +1,40 @@
 package com.algoritmico.passepartout
 
-import android.app.Notification
 import android.content.Intent
 import android.net.VpnService
 import android.os.IBinder
-import androidx.core.app.NotificationChannelCompat
-import androidx.core.app.NotificationCompat
-import androidx.core.app.NotificationManagerCompat
+import android.util.AtomicFile
 import com.algoritmico.passepartout.abi.PassepartoutWrapper
 import io.partout.PartoutVpnServiceRuntime
 import kotlinx.coroutines.CompletableDeferred
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
+import java.io.File
 
 class PassepartoutVpnService: VpnService() {
     private val runtime by lazy {
         PartoutVpnServiceRuntime(
             logTag = Globals.serviceLogTag,
             service = this,
-            engine = VpnEngine(
-                library = PassepartoutWrapper(),
-                bundleProvider = {
-                    readAsset(BUNDLE_FILENAME)
-                },
-                constantsProvider = {
-                    readAsset(CONSTANTS_FILENAME)
-                },
-                cachePathProvider = {
-                    cacheDir.absolutePath
-                }
-            ),
-            stopService = {
-                stopSelf()
-            }
+            engine = engine
         )
     }
 
-    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
-        return runtime.onStartCommand(intent, flags, startId)
-    }
-
-    override fun onDestroy() {
-        runtime.onDestroy()
-        stopForeground(STOP_FOREGROUND_REMOVE)
-        super.onDestroy()
-    }
-
-    override fun onRevoke() {
-        runtime.onRevoke()
-    }
-
-    override fun onBind(intent: Intent?): IBinder? {
-        if (intent?.action == SERVICE_INTERFACE) {
-            return super.onBind(intent)
-        }
-        return runtime.onBind(intent)
-    }
-
-    private fun createNotification(): Notification {
-        val channelId = NOTIFICATION_CHANNEL_ID
-
-        // Create a notification channel (required on Android 8.0+)
-        val channel = NotificationChannelCompat.Builder(
-            channelId,
-            NotificationManagerCompat.IMPORTANCE_LOW // low importance to avoid sound
-        )
-            .setName("Passepartout VPN")
-            .setDescription("Notification for the VPN foreground service")
-            .build()
-
-        NotificationManagerCompat
-            .from(this)
-            .createNotificationChannel(channel)
+    private val engine = object : PartoutVpnServiceRuntime.Engine {
+        private val library = PassepartoutWrapper()
+        private val lastProfileFile: File
+            get() = File(noBackupFilesDir, Globals.PROFILE_LAST_PATH)
 
-        // Build the notification
-        return NotificationCompat.Builder(this, channelId)
-            .setContentTitle("Passepartout Active")
-            .setContentText("VPN is running")
-            .setOngoing(true)
-            .build()
-    }
-
-    private class VpnEngine(
-        private val library: PassepartoutWrapper,
-        private val bundleProvider: suspend () -> String,
-        private val constantsProvider: suspend () -> String,
-        private val cachePathProvider: () -> String
-    ) : PartoutVpnServiceRuntime.Engine {
         override suspend fun start(
             runtime: PartoutVpnServiceRuntime,
             profileJSON: String
         ): PartoutVpnServiceRuntime.Result = withContext(Dispatchers.IO) {
             PartoutVpnServiceRuntime.Result(
                 library.tunnelStart(
-                    bundleProvider(),
-                    constantsProvider(),
+                    readAsset(Globals.BUNDLE_FILENAME),
+                    readAsset(Globals.CONSTANTS_FILENAME),
                     profileJSON,
-                    cachePathProvider(),
+                    cacheDir.absolutePath,
                     runtime
                 ),
                 null
@@ -110,15 +48,48 @@ class PassepartoutVpnService: VpnService() {
             }
             result.await()
         }
+
+        override suspend fun readLastProfile(): String {
+            return withContext(Dispatchers.IO) {
+                AtomicFile(lastProfileFile).openRead().bufferedReader(Charsets.UTF_8).use {
+                    it.readText()
+                }
+            }
+        }
+
+        override suspend fun writeLastProfile(json: String) {
+            withContext(Dispatchers.IO) {
+                val file = AtomicFile(lastProfileFile)
+                val stream = file.startWrite()
+                try {
+                    stream.write(json.toByteArray(Charsets.UTF_8))
+                    file.finishWrite(stream)
+                } catch (e: Exception) {
+                    file.failWrite(stream)
+                    throw e
+                }
+            }
+        }
     }
 
-    companion object {
-        private const val BUNDLE_FILENAME = "bundle.json"
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        return runtime.onStartCommand(intent, flags, startId)
+    }
 
-        private const val CONSTANTS_FILENAME = "constants.json"
+    override fun onDestroy() {
+        runtime.onDestroy()
+        stopForeground(STOP_FOREGROUND_REMOVE)
+        super.onDestroy()
+    }
 
-        private const val NOTIFICATION_ID = 1
+    override fun onRevoke() {
+        runtime.onRevoke()
+    }
 
-        private const val NOTIFICATION_CHANNEL_ID = "vpn_service_channel"
+    override fun onBind(intent: Intent?): IBinder? {
+        if (intent?.action == SERVICE_INTERFACE) {
+            return super.onBind(intent)
+        }
+        return runtime.onBind(intent)
     }
-}
+}

app-android/app/src/main/kotlin/com/algoritmico/passepartout/ui/AppContext.kt

@@ -8,12 +8,12 @@ import android.content.Context
 import android.content.Intent
 import android.util.Log
 import com.algoritmico.passepartout.Globals
+import com.algoritmico.passepartout.PassepartoutVpnService
 import com.algoritmico.passepartout.abi.AppABIProfile
 import com.algoritmico.passepartout.abi.PassepartoutWrapper
 import com.algoritmico.passepartout.abi.helpers.ABIEventDispatcher
 import com.algoritmico.passepartout.abi.models.Event
 import com.algoritmico.passepartout.readAsset
-import com.algoritmico.passepartout.PassepartoutVpnService
 import io.partout.PartoutTunnel
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.flow.MutableSharedFlow
@@ -46,9 +46,9 @@ class AppContext(
         Log.i(Globals.logTag, ">>> Partout $partoutVersion")
         Log.e(Globals.logTag, ">>> Started app")
 
-        val bundle = applicationContext.readAsset(BUNDLE_FILENAME)
-        val constants = applicationContext.readAsset(CONSTANTS_FILENAME)
-        val profilesDirectory = File(applicationContext.noBackupFilesDir, PROFILES_DIRECTORY)
+        val bundle = applicationContext.readAsset(Globals.BUNDLE_FILENAME)
+        val constants = applicationContext.readAsset(Globals.CONSTANTS_FILENAME)
+        val profilesDirectory = File(applicationContext.noBackupFilesDir, Globals.PROFILES_DIRECTORY)
             .apply {
                 mkdirs()
             }
@@ -101,12 +101,4 @@ class AppContext(
         tunnelObservable.close()
         library.appDeinit { _, _ -> }
     }
-
-    companion object {
-        private const val BUNDLE_FILENAME = "bundle.json"
-
-        private const val CONSTANTS_FILENAME = "constants.json"
-
-        private const val PROFILES_DIRECTORY = "profiles-v1"
-    }
 }