fixed locking

mobile/android/app/src/main/kotlin/app/alextran/immich/images/RemoteImagesImpl.kt

@@ -24,10 +24,8 @@ import java.nio.ByteBuffer
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.Executors
 import java.util.concurrent.TimeUnit
-import java.util.concurrent.atomic.AtomicInteger
 import javax.net.ssl.SSLSocketFactory
 import javax.net.ssl.X509TrustManager
-import kotlin.concurrent.Volatile
 
 
 private const val USER_AGENT = "Immich_Android_${BuildConfig.VERSION_NAME}"
@@ -172,8 +170,8 @@ private class CronetImageFetcher(
 ) : ImageFetcher {
   private val engine: CronetEngine
   private val executor = Executors.newSingleThreadExecutor()
-  val active = AtomicInteger(0)
-  @Volatile
+  private val stateLock = Any()
+  private var activeCount = 0
   private var draining = false
 
   init {
@@ -195,10 +193,12 @@ private class CronetImageFetcher(
     onSuccess: (NativeByteBuffer) -> Unit,
     onFailure: (Exception) -> Unit,
   ) {
-    active.incrementAndGet()
-    if (draining) {
-      active.decrementAndGet()
-      throw IllegalStateException("Engine is draining")
+    synchronized(stateLock) {
+      if (draining) {
+        onFailure(IllegalStateException("Engine is draining"))
+        return
+      }
+      activeCount++
     }
 
     val callback = FetchCallback(onSuccess, onFailure, ::onComplete)
@@ -210,23 +210,25 @@ private class CronetImageFetcher(
   }
 
   private fun onComplete() {
-    // Runs on executor thread
-    active.decrementAndGet()
-    tryShutdown()
-  }
-
-  private fun tryShutdown() {
-    // Also on executor thread—no race with onRequestDone
-    if (draining && active.get() == 0) {
+    val shouldShutdown = synchronized(stateLock) {
+      activeCount--
+      draining && activeCount == 0
+    }
+    if (shouldShutdown) {
       engine.shutdown()
       executor.shutdown()
     }
   }
 
   override fun drain() {
-    draining = true
-    // Post check to executor—runs after any already-queued callbacks
-    executor.execute(this::tryShutdown)
+    val shouldShutdown = synchronized(stateLock) {
+      draining = true
+      activeCount == 0
+    }
+    if (shouldShutdown) {
+      engine.shutdown()
+      executor.shutdown()
+    }
   }
 
   private class FetchCallback(
@@ -284,8 +286,9 @@ private class CronetImageFetcher(
 private class OkHttpImageFetcher private constructor(
   private val client: OkHttpClient,
 ) : ImageFetcher {
-  private val active = AtomicInteger(0)
-  @Volatile private var draining = false
+  private val stateLock = Any()
+  private var activeCount = 0
+  private var draining = false
 
   companion object {
     fun create(
@@ -334,7 +337,11 @@ private class OkHttpImageFetcher private constructor(
   }
 
   private fun onComplete() {
-    if (active.decrementAndGet() == 0 && draining) {
+    val shouldClose = synchronized(stateLock) {
+      activeCount--
+      draining && activeCount == 0
+    }
+    if (shouldClose) {
       client.cache?.close()
     }
   }
@@ -346,10 +353,12 @@ private class OkHttpImageFetcher private constructor(
     onSuccess: (NativeByteBuffer) -> Unit,
     onFailure: (Exception) -> Unit,
   ) {
-    active.incrementAndGet()
-    if (draining) {
-      active.decrementAndGet()
-      throw IllegalStateException("Client is draining")
+    synchronized(stateLock) {
+      if (draining) {
+        onFailure(IllegalStateException("Client is draining"))
+        return
+      }
+      activeCount++
     }
 
     val requestBuilder = Request.Builder().url(url)
@@ -409,9 +418,12 @@ private class OkHttpImageFetcher private constructor(
   }
 
   override fun drain() {
-    draining = true
+    val shouldClose = synchronized(stateLock) {
+      draining = true
+      activeCount == 0
+    }
     client.connectionPool.evictAll()
-    if (active.get() == 0) {
+    if (shouldClose) {
       client.cache?.close()
     }
   }