FTP server minor improvements

- Replace EventBus with kotlinx.coroutines
- FtpServerFragment update code to recommended
- FtpService explicitly acquires wakelock and enforces START_STICKY to ensure it's still running in the background even in the doze mode. Fixes TeamAmaze#4125
- Upgrade ACRA to 2.13 for fixing square/leakcanary#2568

Author: TranceLove

app/build.gradle

@@ -196,8 +196,6 @@ dependencies {
     implementation libs.apache.ftpserver.ftplet.api
     implementation libs.apache.ftpserver.core
 
-    implementation libs.eventbus
-
     implementation libs.libsu.core
     implementation libs.libsu.io
 

app/src/main/AndroidManifest.xml

@@ -286,7 +286,8 @@
             android:exported="true"
             android:icon="@drawable/ic_ftp_dark"
             android:label="@string/ftp"
-            android:permission="android.permission.BIND_QUICK_SETTINGS_TILE">
+            android:permission="android.permission.BIND_QUICK_SETTINGS_TILE"
+            tools:targetApi="24">
             <intent-filter>
                 <action
                     android:name="android.service.quicksettings.action.QS_TILE" />

app/src/main/java/com/amaze/filemanager/asynchronous/services/ftp/FtpEventBus.kt

@@ -0,0 +1,28 @@
+package com.amaze.filemanager.asynchronous.services.ftp
+
+import com.amaze.filemanager.ui.fragments.FtpServerFragment
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
+
+/**
+ * Replacement event bus to handle [FtpService] events using Kotlin's Flow.
+ *
+ * Original idea: https://mirchev.medium.com/its-21st-century-stop-using-eventbus-3ff5d9c6a00f
+ *
+ * @see [FtpService]
+ * @see [FtpTileService]
+ * @see [FtpServerFragment]
+ */
+object FtpEventBus {
+    private val _events = MutableSharedFlow<FtpService.FtpReceiverActions>(replay = 0)
+    val events = _events.asSharedFlow()
+
+    /**
+     * Emit the event signal to the event bus as [MutableSharedFlow].
+     *
+     * @param event The event to be emitted.
+     */
+    suspend fun emit(event: FtpService.FtpReceiverActions) {
+        _events.emit(event)
+    }
+}

app/src/main/java/com/amaze/filemanager/asynchronous/services/ftp/FtpService.kt

@@ -40,6 +40,7 @@ import android.os.PowerManager
 import android.os.SystemClock
 import android.provider.DocumentsContract
 import androidx.core.app.ServiceCompat
+import androidx.core.content.edit
 import androidx.preference.PreferenceManager
 import com.amaze.filemanager.BuildConfig
 import com.amaze.filemanager.R
@@ -52,6 +53,10 @@ import com.amaze.filemanager.ui.notifications.FtpNotification
 import com.amaze.filemanager.ui.notifications.NotificationConstants
 import com.amaze.filemanager.utils.ObtainableServiceBinder
 import com.amaze.filemanager.utils.PasswordUtil
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.launch
 import org.apache.ftpserver.ConnectionConfigFactory
 import org.apache.ftpserver.FtpServer
 import org.apache.ftpserver.FtpServerFactory
@@ -61,7 +66,6 @@ import org.apache.ftpserver.ssl.ClientAuth
 import org.apache.ftpserver.ssl.impl.DefaultSslConfiguration
 import org.apache.ftpserver.usermanager.impl.BaseUser
 import org.apache.ftpserver.usermanager.impl.WritePermission
-import org.greenrobot.eventbus.EventBus
 import org.slf4j.Logger
 import org.slf4j.LoggerFactory
 import java.io.IOException
@@ -79,6 +83,7 @@ import kotlin.concurrent.thread
  * Edited by zent-co on 30-07-2019 Edited by bowiechen on 2019-10-19.
  */
 class FtpService : Service(), Runnable {
+    private val serviceScope = CoroutineScope(Dispatchers.Default + SupervisorJob())
     private val binder: IBinder = ObtainableServiceBinder(this)
 
     // Service will broadcast via event bus when server start/stop
@@ -95,6 +100,12 @@ class FtpService : Service(), Runnable {
     private var isStartedByTile = false
     private lateinit var wakeLock: PowerManager.WakeLock
 
+    private fun publishEvent(event: FtpReceiverActions) {
+        serviceScope.launch {
+            FtpEventBus.emit(event)
+        }
+    }
+
     override fun onStartCommand(
         intent: Intent?,
         flags: Int,
@@ -126,7 +137,7 @@ class FtpService : Service(), Runnable {
         } else {
             startForeground(NotificationConstants.FTP_ID, notification)
         }
-        return START_NOT_STICKY
+        return START_STICKY
     }
 
     override fun onCreate() {
@@ -143,6 +154,7 @@ class FtpService : Service(), Runnable {
 
     @Suppress("LongMethod")
     override fun run() {
+        wakeLock.acquire()
         val preferences = PreferenceManager.getDefaultSharedPreferences(this)
         FtpServerFactory().run {
             val connectionConfigFactory = ConnectionConfigFactory()
@@ -175,7 +187,7 @@ class FtpService : Service(), Runnable {
                 }.onFailure {
                     log.warn("failed to decrypt password in ftp service", it)
                     AppConfig.toast(applicationContext, R.string.error)
-                    preferences.edit().putString(KEY_PREFERENCE_PASSWORD, "").apply()
+                    preferences.edit { putString(KEY_PREFERENCE_PASSWORD, "") }
                     isPasswordProtected = false
                 }
             }
@@ -224,9 +236,9 @@ class FtpService : Service(), Runnable {
                         )
                     fac.isImplicitSsl = true
                 } catch (e: GeneralSecurityException) {
-                    preferences.edit().putBoolean(KEY_PREFERENCE_SECURE, false).apply()
+                    preferences.edit { putBoolean(KEY_PREFERENCE_SECURE, false) }
                 } catch (e: IOException) {
-                    preferences.edit().putBoolean(KEY_PREFERENCE_SECURE, false).apply()
+                    preferences.edit { putBoolean(KEY_PREFERENCE_SECURE, false) }
                 }
             }
             fac.port = getPort(preferences)
@@ -237,23 +249,22 @@ class FtpService : Service(), Runnable {
                 server =
                     createServer().apply {
                         start()
-                        EventBus.getDefault()
-                            .post(
-                                if (isStartedByTile) {
-                                    FtpReceiverActions.STARTED_FROM_TILE
-                                } else {
-                                    FtpReceiverActions.STARTED
-                                },
-                            )
+                        publishEvent(
+                            if (isStartedByTile) {
+                                FtpReceiverActions.STARTED_FROM_TILE
+                            } else {
+                                FtpReceiverActions.STARTED
+                            },
+                        )
                     }
             }.onFailure {
-                EventBus.getDefault().post(FtpReceiverActions.FAILED_TO_START)
+                wakeLock.release()
+                publishEvent(FtpReceiverActions.FAILED_TO_START)
             }
         }
     }
 
     override fun onDestroy() {
-        wakeLock.release()
         serverThread?.let { serverThread ->
             serverThread.interrupt()
             // wait 10 sec for server thread to finish
@@ -263,9 +274,13 @@ class FtpService : Service(), Runnable {
                 Companion.serverThread = null
             }
             server?.stop().also {
-                EventBus.getDefault().post(FtpReceiverActions.STOPPED)
+                publishEvent(FtpReceiverActions.STOPPED)
             }
         }
+
+        if (wakeLock.isHeld) {
+            wakeLock.release()
+        }
     }
 
     // Restart the service if the app is closed from the recent list
@@ -312,39 +327,6 @@ class FtpService : Service(), Runnable {
         const val TAG_STARTED_BY_TILE = "started_by_tile"
         // attribute of action_started, used by notification
 
-        private lateinit var _enabledCipherSuites: Array<String>
-
-        init {
-            _enabledCipherSuites =
-                LinkedList<String>().apply {
-                    if (SDK_INT >= Q) {
-                        add("TLS_AES_128_GCM_SHA256")
-                        add("TLS_AES_256_GCM_SHA384")
-                        add("TLS_CHACHA20_POLY1305_SHA256")
-                    }
-                    if (SDK_INT >= N) {
-                        add("TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256")
-                        add("TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256")
-                    }
-                    if (SDK_INT >= LOLLIPOP) {
-                        add("TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA")
-                        add("TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256")
-                        add("TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA")
-                        add("TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384")
-                        add("TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA")
-                        add("TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256")
-                        add("TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA")
-                        add("TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384")
-                        add("TLS_RSA_WITH_AES_128_GCM_SHA256")
-                        add("TLS_RSA_WITH_AES_256_GCM_SHA384")
-                    }
-                    if (SDK_INT < LOLLIPOP) {
-                        add("TLS_RSA_WITH_AES_128_CBC_SHA")
-                        add("TLS_RSA_WITH_AES_256_CBC_SHA")
-                    }
-                }.toTypedArray()
-        }
-
         /**
          * Return a list of available ciphers for ftpserver.
          *
@@ -355,7 +337,34 @@ class FtpService : Service(), Runnable {
          * @see [javax.net.ssl.SSLEngine]
          */
         @JvmStatic
-        val enabledCipherSuites = _enabledCipherSuites
+        val enabledCipherSuites: Array<String> =
+            LinkedList<String>().apply {
+                if (SDK_INT >= Q) {
+                    add("TLS_AES_128_GCM_SHA256")
+                    add("TLS_AES_256_GCM_SHA384")
+                    add("TLS_CHACHA20_POLY1305_SHA256")
+                }
+                if (SDK_INT >= N) {
+                    add("TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256")
+                    add("TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256")
+                }
+                if (SDK_INT >= LOLLIPOP) {
+                    add("TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA")
+                    add("TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256")
+                    add("TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA")
+                    add("TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384")
+                    add("TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA")
+                    add("TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256")
+                    add("TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA")
+                    add("TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384")
+                    add("TLS_RSA_WITH_AES_128_GCM_SHA256")
+                    add("TLS_RSA_WITH_AES_256_GCM_SHA384")
+                }
+                if (SDK_INT < LOLLIPOP) {
+                    add("TLS_RSA_WITH_AES_128_CBC_SHA")
+                    add("TLS_RSA_WITH_AES_256_CBC_SHA")
+                }
+            }.toTypedArray()
 
         private var serverThread: Thread? = null
         private var server: FtpServer? = null