Fix issue when opening encrypted files (#3186)

Also always open the file after a successful download

CHANGES.md

@@ -13,6 +13,7 @@ Bugfix 🐛:
  - Do not invite the current user when creating a room (#3123)
  - Fix color issues when the system theme is changed (#2738)
  - Fix issues on Android 11 (#3067)
+ - Fix issue when opening encrypted files (#3186)
 
 Translations 🗣:
  -

matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/file/FileService.kt

@@ -29,14 +29,19 @@ import java.io.File
  */
 interface FileService {
 
-    enum class FileState {
+    sealed class FileState {
-        IN_CACHE,
+        /**
-        DOWNLOADING,
+         * The original file is in cache, but the decrypted files can be deleted for security reason.
-        UNKNOWN
+         * To decrypt the file again, call [downloadFile], the encrypted file will not be downloaded again
+         * @param decryptedFileInCache true if the decrypted file is available. Always true for clear files.
+         */
+        data class InCache(val decryptedFileInCache: Boolean) : FileState()
+        object Downloading : FileState()
+        object Unknown : FileState()
     }
 
     /**
-     * Download a file.
+     * Download a file if necessary and ensure that if the file is encrypted, the file is decrypted.
      * Result will be a decrypted file, stored in the cache folder. url parameter will be used to create unique filename to avoid name collision.
      */
     suspend fun downloadFile(fileName: String,

matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/DefaultFileService.kt

@@ -219,7 +219,7 @@ internal class DefaultFileService @Inject constructor(
                                fileName: String,
                                mimeType: String?,
                                elementToDecrypt: ElementToDecrypt?): Boolean {
-        return fileState(mxcUrl, fileName, mimeType, elementToDecrypt) == FileService.FileState.IN_CACHE
+        return fileState(mxcUrl, fileName, mimeType, elementToDecrypt) is FileService.FileState.InCache
     }
 
     internal data class CachedFiles(
@@ -256,12 +256,17 @@ internal class DefaultFileService @Inject constructor(
                            fileName: String,
                            mimeType: String?,
                            elementToDecrypt: ElementToDecrypt?): FileService.FileState {
-        mxcUrl ?: return FileService.FileState.UNKNOWN
+        mxcUrl ?: return FileService.FileState.Unknown
-        if (getFiles(mxcUrl, fileName, mimeType, elementToDecrypt != null).file.exists()) return FileService.FileState.IN_CACHE
+        val files = getFiles(mxcUrl, fileName, mimeType, elementToDecrypt != null)
+        if (files.file.exists()) {
+            return FileService.FileState.InCache(
+                    decryptedFileInCache = files.getClearFile().exists()
+            )
+        }
         val isDownloading = synchronized(ongoing) {
             ongoing[mxcUrl] != null
         }
-        return if (isDownloading) FileService.FileState.DOWNLOADING else FileService.FileState.UNKNOWN
+        return if (isDownloading) FileService.FileState.Downloading else FileService.FileState.Unknown
     }
 
     /**

vector/src/main/java/im/vector/app/features/home/room/detail/RoomDetailViewModel.kt

@@ -78,6 +78,7 @@ import org.matrix.android.sdk.api.session.events.model.isAttachmentMessage
 import org.matrix.android.sdk.api.session.events.model.isTextMessage
 import org.matrix.android.sdk.api.session.events.model.toContent
 import org.matrix.android.sdk.api.session.events.model.toModel
+import org.matrix.android.sdk.api.session.file.FileService
 import org.matrix.android.sdk.api.session.homeserver.HomeServerCapabilities
 import org.matrix.android.sdk.api.session.room.members.ChangeMembershipState
 import org.matrix.android.sdk.api.session.room.members.roomMemberQueryParams
@@ -1138,7 +1139,6 @@ class RoomDetailViewModel @AssistedInject constructor(
         val mxcUrl = action.messageFileContent.getFileUrl() ?: return
         val isLocalSendingFile = action.senderId == session.myUserId
                 && mxcUrl.startsWith("content://")
-        val isDownloaded = session.fileService().isFileInCache(action.messageFileContent)
         if (isLocalSendingFile) {
             tryOrNull { Uri.parse(mxcUrl) }?.let {
                 _viewEvents.post(RoomDetailViewEvents.OpenFile(
@@ -1147,17 +1147,12 @@ class RoomDetailViewModel @AssistedInject constructor(
                         null
                 ))
             }
-        } else if (isDownloaded) {
-            // we can open it
-            session.fileService().getTemporarySharableURI(action.messageFileContent)?.let { uri ->
-                _viewEvents.post(RoomDetailViewEvents.OpenFile(
-                        action.messageFileContent.mimeType,
-                        uri,
-                        null
-                ))
-            }
         } else {
             viewModelScope.launch {
+                val fileState = session.fileService().fileState(action.messageFileContent)
+                var canOpen = fileState is FileService.FileState.InCache && fileState.decryptedFileInCache
+                if (!canOpen) {
+                    // First download, or download and decrypt, or decrypt from cache
                     val result = runCatching {
                         session.fileService().downloadFile(messageContent = action.messageFileContent)
                     }
@@ -1167,6 +1162,19 @@ class RoomDetailViewModel @AssistedInject constructor(
                             result.getOrNull(),
                             result.exceptionOrNull()
                     ))
+                    canOpen = result.isSuccess
+                }
+
+                if (canOpen) {
+                    // We can now open the file
+                    session.fileService().getTemporarySharableURI(action.messageFileContent)?.let { uri ->
+                        _viewEvents.post(RoomDetailViewEvents.OpenFile(
+                                action.messageFileContent.mimeType,
+                                uri,
+                                null
+                        ))
+                    }
+                }
             }
         }
     }