fix: prevent background worker when main app is running (#22252)

* fix: prevent background worker only when the main app is actively running * handle ref disposals better --------- Co-authored-by: shenlong-tanwen <139912620+shalong-tanwen@users.noreply.github.com> Co-authored-by: Alex <alex.tran1502@gmail.com>
2025-12-12 15:50:43 -08:00 · 2025-09-22 07:15:47 +05:30
parent b33e8abcdd
commit 35b62cd016
15 changed files with 418 additions and 95 deletions
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/MainActivity.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/MainActivity.kt
@@ -6,6 +6,7 @@ import android.os.ext.SdkExtensions
 import app.alextran.immich.background.BackgroundEngineLock
 import app.alextran.immich.background.BackgroundWorkerApiImpl
 import app.alextran.immich.background.BackgroundWorkerFgHostApi
+import app.alextran.immich.background.BackgroundWorkerLockApi
 import app.alextran.immich.connectivity.ConnectivityApi
 import app.alextran.immich.connectivity.ConnectivityApiImpl
 import app.alextran.immich.images.ThumbnailApi
@@ -24,11 +25,9 @@ class MainActivity : FlutterFragmentActivity() {

  companion object {
    fun registerPlugins(ctx: Context, flutterEngine: FlutterEngine) {
-      flutterEngine.plugins.add(BackgroundServicePlugin())
-      flutterEngine.plugins.add(HttpSSLOptionsPlugin())
-      flutterEngine.plugins.add(BackgroundEngineLock())
-
      val messenger = flutterEngine.dartExecutor.binaryMessenger
+      val backgroundEngineLockImpl = BackgroundEngineLock(ctx)
+      BackgroundWorkerLockApi.setUp(messenger, backgroundEngineLockImpl)
      val nativeSyncApiImpl =
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.R || SdkExtensions.getExtensionVersion(Build.VERSION_CODES.R) < 1) {
          NativeSyncApiImpl26(ctx)
@@ -39,6 +38,10 @@ class MainActivity : FlutterFragmentActivity() {
      ThumbnailApi.setUp(messenger, ThumbnailsImpl(ctx))
      BackgroundWorkerFgHostApi.setUp(messenger, BackgroundWorkerApiImpl(ctx))
      ConnectivityApi.setUp(messenger, ConnectivityApiImpl(ctx))
+
+      flutterEngine.plugins.add(BackgroundServicePlugin())
+      flutterEngine.plugins.add(HttpSSLOptionsPlugin())
+      flutterEngine.plugins.add(backgroundEngineLockImpl)
    }
  }
 }
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundEngineLock.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundEngineLock.kt
@@ -1,33 +1,50 @@
 package app.alextran.immich.background

+import android.content.Context
 import android.util.Log
-import androidx.work.WorkManager
-import io.flutter.embedding.engine.FlutterEngineCache
 import io.flutter.embedding.engine.plugins.FlutterPlugin
 import java.util.concurrent.atomic.AtomicInteger

 private const val TAG = "BackgroundEngineLock"

-class BackgroundEngineLock : FlutterPlugin {
-  companion object {
-    const val ENGINE_CACHE_KEY = "immich::background_worker::engine"
-    var engineCount = AtomicInteger(0)
-  }
+class BackgroundEngineLock(context: Context) : BackgroundWorkerLockApi, FlutterPlugin {
+    private val ctx: Context = context.applicationContext

-  override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
-    // work manager task is running while the main app is opened, cancel the worker
-    if (engineCount.incrementAndGet() > 1 && FlutterEngineCache.getInstance()
-        .get(ENGINE_CACHE_KEY) != null
-    ) {
-      WorkManager.getInstance(binding.applicationContext)
-        .cancelUniqueWork(BackgroundWorkerApiImpl.BACKGROUND_WORKER_NAME)
-      FlutterEngineCache.getInstance().remove(ENGINE_CACHE_KEY)
+    companion object {
+
+        private var engineCount = AtomicInteger(0)
+
+        private fun checkAndEnforceBackgroundLock(ctx: Context) {
+            // work manager task is running while the main app is opened, cancel the worker
+            if (BackgroundWorkerPreferences(ctx).isLocked() &&
+                engineCount.get() > 1 &&
+                BackgroundWorkerApiImpl.isBackgroundWorkerRunning()
+            ) {
+                Log.i(TAG, "Background worker is locked, cancelling the background worker")
+                BackgroundWorkerApiImpl.cancelBackgroundWorker(ctx)
+            }
+        }
    }
-    Log.i(TAG, "Flutter engine attached. Attached Engines count: $engineCount")
-  }

-  override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
-    engineCount.decrementAndGet()
-    Log.i(TAG, "Flutter engine detached. Attached Engines count: $engineCount")
-  }
+    override fun lock() {
+        BackgroundWorkerPreferences(ctx).setLocked(true)
+        checkAndEnforceBackgroundLock(ctx)
+        Log.i(TAG, "Background worker is locked")
+    }
+
+    override fun unlock() {
+        BackgroundWorkerPreferences(ctx).setLocked(false)
+        Log.i(TAG, "Background worker is unlocked")
+    }
+
+    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+        checkAndEnforceBackgroundLock(binding.applicationContext)
+        engineCount.incrementAndGet()
+        Log.i(TAG, "Flutter engine attached. Attached Engines count: $engineCount")
+    }
+
+    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+        engineCount.decrementAndGet()
+        Log.i(TAG, "Flutter engine detached. Attached Engines count: $engineCount")
+    }
 }
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorker.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorker.kt
@@ -76,9 +76,7 @@ class BackgroundWorker(context: Context, params: WorkerParameters) :

    loader.ensureInitializationCompleteAsync(ctx, null, Handler(Looper.getMainLooper())) {
      engine = FlutterEngine(ctx)
-      FlutterEngineCache.getInstance().remove(BackgroundEngineLock.ENGINE_CACHE_KEY);
-      FlutterEngineCache.getInstance()
-        .put(BackgroundEngineLock.ENGINE_CACHE_KEY, engine!!)
+      FlutterEngineCache.getInstance().put(BackgroundWorkerApiImpl.ENGINE_CACHE_KEY, engine!!)

      // Register custom plugins
      MainActivity.registerPlugins(ctx, engine!!)
@@ -192,9 +190,9 @@ class BackgroundWorker(context: Context, params: WorkerParameters) :
    isComplete = true
    engine?.destroy()
    engine = null
-    FlutterEngineCache.getInstance().remove(BackgroundEngineLock.ENGINE_CACHE_KEY);
    flutterApi = null
    notificationManager.cancel(NOTIFICATION_ID)
+    FlutterEngineCache.getInstance().remove(BackgroundWorkerApiImpl.ENGINE_CACHE_KEY)
    waitForForegroundPromotion()
    completionHandler.set(success)
  }
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorkerApiImpl.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorkerApiImpl.kt
@@ -1,7 +1,6 @@
 package app.alextran.immich.background

 import android.content.Context
-import android.content.SharedPreferences
 import android.provider.MediaStore
 import android.util.Log
 import androidx.work.BackoffPolicy
@@ -9,6 +8,7 @@ import androidx.work.Constraints
 import androidx.work.ExistingWorkPolicy
 import androidx.work.OneTimeWorkRequest
 import androidx.work.WorkManager
+import io.flutter.embedding.engine.FlutterEngineCache
 import java.util.concurrent.TimeUnit

 private const val TAG = "BackgroundWorkerApiImpl"
@@ -34,8 +34,10 @@ class BackgroundWorkerApiImpl(context: Context) : BackgroundWorkerFgHostApi {
  }

  companion object {
-    const val BACKGROUND_WORKER_NAME = "immich/BackgroundWorkerV1"
+    private const val BACKGROUND_WORKER_NAME = "immich/BackgroundWorkerV1"
    private const val OBSERVER_WORKER_NAME = "immich/MediaObserverV1"
+    const val ENGINE_CACHE_KEY = "immich::background_worker::engine"
+

    fun enqueueMediaObserver(ctx: Context) {
      val settings = BackgroundWorkerPreferences(ctx).getSettings()
@@ -73,35 +75,18 @@ class BackgroundWorkerApiImpl(context: Context) : BackgroundWorkerFgHostApi {

      Log.i(TAG, "Enqueued background worker with name: $BACKGROUND_WORKER_NAME")
    }
-  }
-}

-private class BackgroundWorkerPreferences(private val ctx: Context) {
-  companion object {
-    private const val SHARED_PREF_NAME = "Immich::BackgroundWorker"
-    private const val SHARED_PREF_MIN_DELAY_KEY = "BackgroundWorker::minDelaySeconds"
-    private const val SHARED_PREF_REQUIRE_CHARGING_KEY = "BackgroundWorker::requireCharging"
+    fun isBackgroundWorkerRunning(): Boolean {
+      // Easier to check if the engine is cached as we always cache the engine when starting the worker
+      // and remove it when the worker is finished
+      return FlutterEngineCache.getInstance().get(ENGINE_CACHE_KEY) != null
+    }

-    private const val DEFAULT_MIN_DELAY_SECONDS = 30L
-    private const val DEFAULT_REQUIRE_CHARGING = false
-  }
+    fun cancelBackgroundWorker(ctx: Context) {
+      WorkManager.getInstance(ctx).cancelUniqueWork(BACKGROUND_WORKER_NAME)
+      FlutterEngineCache.getInstance().remove(ENGINE_CACHE_KEY)

-  private val sp: SharedPreferences by lazy {
-    ctx.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE)
-  }
-
-  fun updateSettings(settings: BackgroundWorkerSettings) {
-    sp.edit().apply {
-      putLong(SHARED_PREF_MIN_DELAY_KEY, settings.minimumDelaySeconds)
-      putBoolean(SHARED_PREF_REQUIRE_CHARGING_KEY, settings.requiresCharging)
-      apply()
+      Log.i(TAG, "Cancelled background upload task")
    }
  }
-
-  fun getSettings(): BackgroundWorkerSettings {
-    return BackgroundWorkerSettings(
-      minimumDelaySeconds = sp.getLong(SHARED_PREF_MIN_DELAY_KEY, DEFAULT_MIN_DELAY_SECONDS),
-      requiresCharging = sp.getBoolean(SHARED_PREF_REQUIRE_CHARGING_KEY, DEFAULT_REQUIRE_CHARGING),
-    )
-  }
 }
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorkerLock.g.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorkerLock.g.kt
@@ -0,0 +1,95 @@
+// Autogenerated from Pigeon (v26.0.0), do not edit directly.
+// See also: https://pub.dev/packages/pigeon
+@file:Suppress("UNCHECKED_CAST", "ArrayInDataClass")
+
+package app.alextran.immich.background
+
+import android.util.Log
+import io.flutter.plugin.common.BasicMessageChannel
+import io.flutter.plugin.common.BinaryMessenger
+import io.flutter.plugin.common.EventChannel
+import io.flutter.plugin.common.MessageCodec
+import io.flutter.plugin.common.StandardMethodCodec
+import io.flutter.plugin.common.StandardMessageCodec
+import java.io.ByteArrayOutputStream
+import java.nio.ByteBuffer
+private object BackgroundWorkerLockPigeonUtils {
+
+  fun wrapResult(result: Any?): List<Any?> {
+    return listOf(result)
+  }
+
+  fun wrapError(exception: Throwable): List<Any?> {
+    return if (exception is FlutterError) {
+      listOf(
+        exception.code,
+        exception.message,
+        exception.details
+      )
+    } else {
+      listOf(
+        exception.javaClass.simpleName,
+        exception.toString(),
+        "Cause: " + exception.cause + ", Stacktrace: " + Log.getStackTraceString(exception)
+      )
+    }
+  }
+}
+private open class BackgroundWorkerLockPigeonCodec : StandardMessageCodec() {
+  override fun readValueOfType(type: Byte, buffer: ByteBuffer): Any? {
+    return     super.readValueOfType(type, buffer)
+  }
+  override fun writeValue(stream: ByteArrayOutputStream, value: Any?)   {
+    super.writeValue(stream, value)
+  }
+}
+
+/** Generated interface from Pigeon that represents a handler of messages from Flutter. */
+interface BackgroundWorkerLockApi {
+  fun lock()
+  fun unlock()
+
+  companion object {
+    /** The codec used by BackgroundWorkerLockApi. */
+    val codec: MessageCodec<Any?> by lazy {
+      BackgroundWorkerLockPigeonCodec()
+    }
+    /** Sets up an instance of `BackgroundWorkerLockApi` to handle messages through the `binaryMessenger`. */
+    @JvmOverloads
+    fun setUp(binaryMessenger: BinaryMessenger, api: BackgroundWorkerLockApi?, messageChannelSuffix: String = "") {
+      val separatedMessageChannelSuffix = if (messageChannelSuffix.isNotEmpty()) ".$messageChannelSuffix" else ""
+      run {
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.BackgroundWorkerLockApi.lock$separatedMessageChannelSuffix", codec)
+        if (api != null) {
+          channel.setMessageHandler { _, reply ->
+            val wrapped: List<Any?> = try {
+              api.lock()
+              listOf(null)
+            } catch (exception: Throwable) {
+              BackgroundWorkerLockPigeonUtils.wrapError(exception)
+            }
+            reply.reply(wrapped)
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
+      run {
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.BackgroundWorkerLockApi.unlock$separatedMessageChannelSuffix", codec)
+        if (api != null) {
+          channel.setMessageHandler { _, reply ->
+            val wrapped: List<Any?> = try {
+              api.unlock()
+              listOf(null)
+            } catch (exception: Throwable) {
+              BackgroundWorkerLockPigeonUtils.wrapError(exception)
+            }
+            reply.reply(wrapped)
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
+    }
+  }
+}
--- a/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorkerPreferences.kt
+++ b/mobile/android/app/src/main/kotlin/app/alextran/immich/background/BackgroundWorkerPreferences.kt
@@ -0,0 +1,49 @@
+package app.alextran.immich.background
+
+import android.content.Context
+import android.content.SharedPreferences
+import androidx.core.content.edit
+
+class BackgroundWorkerPreferences(private val ctx: Context) {
+    companion object {
+        const val SHARED_PREF_NAME = "Immich::BackgroundWorker"
+        private const val SHARED_PREF_MIN_DELAY_KEY = "BackgroundWorker::minDelaySeconds"
+        private const val SHARED_PREF_REQUIRE_CHARGING_KEY = "BackgroundWorker::requireCharging"
+        private const val SHARED_PREF_LOCK_KEY = "BackgroundWorker::isLocked"
+
+        private const val DEFAULT_MIN_DELAY_SECONDS = 30L
+        private const val DEFAULT_REQUIRE_CHARGING = false
+    }
+
+    private val sp: SharedPreferences by lazy {
+        ctx.getSharedPreferences(SHARED_PREF_NAME, Context.MODE_PRIVATE)
+    }
+
+    fun updateSettings(settings: BackgroundWorkerSettings) {
+        sp.edit {
+            putLong(SHARED_PREF_MIN_DELAY_KEY, settings.minimumDelaySeconds)
+            putBoolean(SHARED_PREF_REQUIRE_CHARGING_KEY, settings.requiresCharging)
+        }
+    }
+
+    fun getSettings(): BackgroundWorkerSettings {
+        return BackgroundWorkerSettings(
+            minimumDelaySeconds = sp.getLong(SHARED_PREF_MIN_DELAY_KEY, DEFAULT_MIN_DELAY_SECONDS),
+            requiresCharging = sp.getBoolean(
+                SHARED_PREF_REQUIRE_CHARGING_KEY,
+                DEFAULT_REQUIRE_CHARGING
+            ),
+        )
+    }
+
+    fun setLocked(paused: Boolean) {
+        sp.edit {
+            putBoolean(SHARED_PREF_LOCK_KEY, paused)
+        }
+    }
+
+    fun isLocked(): Boolean {
+        return sp.getBoolean(SHARED_PREF_LOCK_KEY, true)
+    }
+}
+