feat(mobile): hash assets in isolate (#18924)

mobile/android/app/src/main/kotlin/app/alextran/immich/sync/Messages.g.kt

@@ -247,6 +247,7 @@ interface NativeSyncApi {
   fun getAlbums(): List<PlatformAlbum>
   fun getAssetsCountSince(albumId: String, timestamp: Long): Long
   fun getAssetsForAlbum(albumId: String, updatedTimeCond: Long?): List<PlatformAsset>
+  fun hashPaths(paths: List<String>): List<ByteArray?>
 
   companion object {
     /** The codec used by NativeSyncApi. */
@@ -388,6 +389,23 @@ interface NativeSyncApi {
           channel.setMessageHandler(null)
         }
       }
+      run {
+        val channel = BasicMessageChannel<Any?>(binaryMessenger, "dev.flutter.pigeon.immich_mobile.NativeSyncApi.hashPaths$separatedMessageChannelSuffix", codec, taskQueue)
+        if (api != null) {
+          channel.setMessageHandler { message, reply ->
+            val args = message as List<Any?>
+            val pathsArg = args[0] as List<String>
+            val wrapped: List<Any?> = try {
+              listOf(api.hashPaths(pathsArg))
+            } catch (exception: Throwable) {
+              MessagesPigeonUtils.wrapError(exception)
+            }
+            reply.reply(wrapped)
+          }
+        } else {
+          channel.setMessageHandler(null)
+        }
+      }
     }
   }
 }

mobile/android/app/src/main/kotlin/app/alextran/immich/sync/MessagesImplBase.kt

@@ -4,7 +4,10 @@ import android.annotation.SuppressLint
 import android.content.Context
 import android.database.Cursor
 import android.provider.MediaStore
+import android.util.Log
 import java.io.File
+import java.io.FileInputStream
+import java.security.MessageDigest
 
 sealed class AssetResult {
   data class ValidAsset(val asset: PlatformAsset, val albumId: String) : AssetResult()
@@ -16,6 +19,8 @@ open class NativeSyncApiImplBase(context: Context) {
   private val ctx: Context = context.applicationContext
 
   companion object {
+    private const val TAG = "NativeSyncApiImplBase"
+
     const val MEDIA_SELECTION =
       "(${MediaStore.Files.FileColumns.MEDIA_TYPE} = ? OR ${MediaStore.Files.FileColumns.MEDIA_TYPE} = ?)"
     val MEDIA_SELECTION_ARGS = arrayOf(
@@ -34,6 +39,8 @@ open class NativeSyncApiImplBase(context: Context) {
       MediaStore.MediaColumns.BUCKET_ID,
       MediaStore.MediaColumns.DURATION
     )
+
+    const val HASH_BUFFER_SIZE = 2 * 1024 * 1024
   }
 
   protected fun getCursor(
@@ -174,4 +181,24 @@ open class NativeSyncApiImplBase(context: Context) {
       .mapNotNull { result -> (result as? AssetResult.ValidAsset)?.asset }
       .toList()
   }
+
+  fun hashPaths(paths: List<String>): List<ByteArray?> {
+    val buffer = ByteArray(HASH_BUFFER_SIZE)
+    val digest = MessageDigest.getInstance("SHA-1")
+
+    return paths.map { path ->
+      try {
+        FileInputStream(path).use { file ->
+          var bytesRead: Int
+          while (file.read(buffer).also { bytesRead = it } > 0) {
+            digest.update(buffer, 0, bytesRead)
+          }
+        }
+        digest.digest()
+      } catch (e: Exception) {
+        Log.w(TAG, "Failed to hash file $path: $e")
+        null
+      }
+    }
+  }
 }