file resumption support

android/app/src/main/kotlin/im/cwtch/flwtch/FlwtchWorker.kt

@@ -112,24 +112,26 @@ class FlwtchWorker(context: Context, parameters: WorkerParameters) :
                             if (dlID == null) {
                                 dlID = 0;
                             }
-                            val channelId =
+                            if (progress >= 0) {
-                                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+                                val channelId =
-                                        createDownloadNotificationChannel(fileKey, fileKey)
+                                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-                                    } else {
+                                            createDownloadNotificationChannel(fileKey, fileKey)
-                                        // If earlier version channel ID is not used
+                                        } else {
-                                        // https://developer.android.com/reference/android/support/v4/app/NotificationCompat.Builder.html#NotificationCompat.Builder(android.content.Context)
+                                            // If earlier version channel ID is not used
-                                        ""
+                                            // https://developer.android.com/reference/android/support/v4/app/NotificationCompat.Builder.html#NotificationCompat.Builder(android.content.Context)
-                                    };
+                                            ""
-                            val newNotification = NotificationCompat.Builder(applicationContext, channelId)
+                                        };
-                                    .setOngoing(true)
+                                val newNotification = NotificationCompat.Builder(applicationContext, channelId)
-                                    .setContentTitle("Downloading")//todo: translate
+                                        .setOngoing(true)
-                                    .setContentText(title)
+                                        .setContentTitle("Downloading")//todo: translate
-                                    .setSmallIcon(android.R.drawable.stat_sys_download)
+                                        .setContentText(title)
-                                    .setProgress(progressMax, progress, false)
+                                        .setSmallIcon(android.R.drawable.stat_sys_download)
-                                    .setSound(null)
+                                        .setProgress(progressMax, progress, false)
-                                    //.setSilent(true)
+                                        .setSound(null)
-                                    .build();
+                                        //.setSilent(true)
-                            notificationManager.notify(dlID, newNotification);
+                                        .build();
+                                notificationManager.notify(dlID, newNotification);
+                            }
                         } catch (e: Exception) {
                             Log.i("FlwtchWorker->FileDownloadProgressUpdate", e.toString() + " :: " + e.getStackTrace());
                         }
@@ -241,6 +243,12 @@ class FlwtchWorker(context: Context, parameters: WorkerParameters) :
                 val fileKey = (a.get("fileKey") as? String) ?: ""
                 Cwtch.checkDownloadStatus(profile, fileKey)
             }
+            "VerifyOrResumeDownload" -> {
+                val profile = (a.get("ProfileOnion") as? String) ?: ""
+                val handle = (a.get("handle") as? String) ?: ""
+                val fileKey = (a.get("fileKey") as? String) ?: ""
+                Cwtch.verifyOrResumeDownload(profile, handle, fileKey)
+            }
             "SendProfileEvent" -> {
                 val onion = (a.get("onion") as? String) ?: ""
                 val jsonEvent = (a.get("jsonEvent") as? String) ?: ""

lib/cwtch/cwtch.dart

@@ -48,6 +48,8 @@ abstract class Cwtch {
   void CreateDownloadableFile(String profile, String handle, String filenameSuggestion, String filekey);
   // ignore: non_constant_identifier_names
   void CheckDownloadStatus(String profile, String fileKey);
+  // ignore: non_constant_identifier_names
+  void VerifyOrResumeDownload(String profile, String handle, String filekey);
 
   // ignore: non_constant_identifier_names
   void ArchiveConversation(String profile, String handle);

lib/cwtch/cwtchNotifier.dart

@@ -340,7 +340,12 @@ class CwtchNotifier {
         profileCN.getProfile(data["ProfileOnion"])?.downloadMarkManifest(data["FileKey"]);
         break;
       case "FileDownloadProgressUpdate":
-        profileCN.getProfile(data["ProfileOnion"])?.downloadUpdate(data["FileKey"], int.parse(data["Progress"]));
+        var progress = int.parse(data["Progress"]);
+        profileCN.getProfile(data["ProfileOnion"])?.downloadUpdate(data["FileKey"], progress, int.parse(data["FileSizeInChunks"]));
+        // progress == -1 is a "download was interrupted" message and should contain a path
+        if (progress < 0) {
+          profileCN.getProfile(data["ProfileOnion"])?.downloadSetPath(data["FileKey"], data["FilePath"]);
+        }
         break;
       case "FileDownloaded":
         profileCN.getProfile(data["ProfileOnion"])?.downloadMarkFinished(data["FileKey"], data["FilePath"]);

lib/cwtch/ffi.dart

@@ -410,6 +410,22 @@ class CwtchFfi implements Cwtch {
     malloc.free(u2);
   }
 
+  @override
+  // ignore: non_constant_identifier_names
+  void VerifyOrResumeDownload(String profileOnion, String contactHandle, String filekey) {
+    var fn = library.lookup<NativeFunction<void_from_string_string_string_function>>("c_VerifyOrResumeDownload");
+    // ignore: non_constant_identifier_names
+    final VerifyOrResumeDownload = fn.asFunction<VoidFromStringStringStringFn>();
+    final u1 = profileOnion.toNativeUtf8();
+    final u2 = contactHandle.toNativeUtf8();
+    final u3 = filekey.toNativeUtf8();
+    VerifyOrResumeDownload(u1, u1.length, u2, u2.length, u3, u3.length);
+    malloc.free(u1);
+    malloc.free(u2);
+    malloc.free(u3);
+  }
+
+
   @override
   // ignore: non_constant_identifier_names
   void ResetTor() {

lib/cwtch/gomobile.dart

@@ -154,6 +154,12 @@ class CwtchGomobile implements Cwtch {
     cwtchPlatform.invokeMethod("CheckDownloadStatus", {"ProfileOnion": profileOnion, "fileKey": fileKey});
   }
 
+  @override
+  // ignore: non_constant_identifier_names
+  void VerifyOrResumeDownload(String profileOnion, String contactHandle, String filekey) {
+    cwtchPlatform.invokeMethod("VerifyOrResumeDownload", {"ProfileOnion": profileOnion, "handle": contactHandle, "filekey": filekey});
+  }
+
   @override
   // ignore: non_constant_identifier_names
   void ResetTor() {

lib/model.dart

@@ -362,11 +362,21 @@ class ProfileInfoState extends ChangeNotifier {
     this._downloads[fileKey] = FileDownloadProgress(numChunks, DateTime.now());
   }
 
-  void downloadUpdate(String fileKey, int progress) {
+  void downloadUpdate(String fileKey, int progress, int numChunks) {
     if (!downloadActive(fileKey)) {
-      print("error: received progress for unknown download " + fileKey);
+      if (progress < 0) {
+        this._downloads[fileKey] = FileDownloadProgress(numChunks, DateTime.now());
+        this._downloads[fileKey]!.interrupted = true;
+        notifyListeners();
+      } else {
+        print("error: received progress for unknown download " + fileKey);
+      }
     } else {
+      if (this._downloads[fileKey]!.interrupted) {
+        this._downloads[fileKey]!.interrupted = false;
+      }
       this._downloads[fileKey]!.chunksDownloaded = progress;
+      this._downloads[fileKey]!.chunksTotal = numChunks;
       notifyListeners();
     }
   }
@@ -394,7 +404,7 @@ class ProfileInfoState extends ChangeNotifier {
   }
 
   bool downloadActive(String fileKey) {
-    return this._downloads.containsKey(fileKey);
+    return this._downloads.containsKey(fileKey) && !this._downloads[fileKey]!.interrupted;
   }
 
   bool downloadGotManifest(String fileKey) {
@@ -405,10 +415,27 @@ class ProfileInfoState extends ChangeNotifier {
     return this._downloads.containsKey(fileKey) && this._downloads[fileKey]!.complete;
   }
 
+  bool downloadInterrupted(String fileKey) {
+    return this._downloads.containsKey(fileKey) && this._downloads[fileKey]!.interrupted;
+  }
+
+  void downloadMarkResumed(String fileKey) {
+    if (this._downloads.containsKey(fileKey)) {
+      this._downloads[fileKey]!.interrupted = false;
+    }
+  }
+
   double downloadProgress(String fileKey) {
     return this._downloads.containsKey(fileKey) ? this._downloads[fileKey]!.progress() : 0.0;
   }
 
+  // used for loading interrupted download info; use downloadMarkFinished for successful downloads
+  void downloadSetPath(String fileKey, String path) {
+    if (this._downloads.containsKey(fileKey)) {
+      this._downloads[fileKey]!.downloadedTo = path;
+    }
+  }
+
   String? downloadFinalPath(String fileKey) {
     return this._downloads.containsKey(fileKey) ? this._downloads[fileKey]!.downloadedTo : null;
   }
@@ -431,6 +458,7 @@ class FileDownloadProgress {
   int chunksTotal = 1;
   bool complete = false;
   bool gotManifest = false;
+  bool interrupted = false;
   String? downloadedTo;
   DateTime? timeStart;
   DateTime? timeEnd;

lib/models/messages/filemessage.dart

@@ -12,6 +12,7 @@ import '../../model.dart';
 class FileMessage extends Message {
   final MessageMetadata metadata;
   final String content;
+  final RegExp nonHex = RegExp(r'[^a-f0-9]');
 
   FileMessage(this.metadata, this.content);
 
@@ -30,6 +31,10 @@ class FileMessage extends Message {
           String nonce = shareObj['n'] as String;
           int fileSize = shareObj['s'] as int;
 
+          if (!validHash(rootHash, nonce)) {
+            return MessageRow(MalformedBubble());
+          }
+
           return MessageRow(FileBubble(nameSuggestion, rootHash, nonce, fileSize), key: Provider.of<ContactInfoState>(bcontext).getMessageKey(idx));
         });
   }
@@ -47,6 +52,9 @@ class FileMessage extends Message {
           String rootHash = shareObj['h'] as String;
           String nonce = shareObj['n'] as String;
           int fileSize = shareObj['s'] as int;
+          if (!validHash(rootHash, nonce)) {
+            return MessageRow(MalformedBubble());
+          }
           return FileBubble(
             nameSuggestion,
             rootHash,
@@ -61,4 +69,8 @@ class FileMessage extends Message {
   MessageMetadata getMetadata() {
     return this.metadata;
   }
+
+  bool validHash(String hash, String nonce) {
+    return hash.length == 128 && nonce.length == 48 && !hash.contains(nonHex) && !nonce.contains(nonHex);
+  }
 }

lib/widgets/filebubble.dart

@@ -33,6 +33,11 @@ class FileBubble extends StatefulWidget {
 }
 
 class FileBubbleState extends State<FileBubble> {
+  @override
+  void initState() {
+    super.initState();
+  }
+
   @override
   Widget build(BuildContext context) {
     var fromMe = Provider.of<MessageMetadata>(context).senderHandle == Provider.of<ProfileInfoState>(context).onion;
@@ -71,7 +76,7 @@ class FileBubbleState extends State<FileBubble> {
     } else if (Provider.of<ProfileInfoState>(context).downloadComplete(widget.fileKey())) {
       // in this case, whatever marked download.complete would have also set the path
       var path = Provider.of<ProfileInfoState>(context).downloadFinalPath(widget.fileKey())!;
-      wdgDecorations = Text('Saved to: ' + path + '\u202F');
+      wdgDecorations = Text(AppLocalizations.of(context)!.fileSavedTo + ': ' + path + '\u202F');
     } else if (Provider.of<ProfileInfoState>(context).downloadActive(widget.fileKey())) {
       if (!Provider.of<ProfileInfoState>(context).downloadGotManifest(widget.fileKey())) {
         wdgDecorations = Text(AppLocalizations.of(context)!.retrievingManifestMessage + '\u202F');
@@ -84,12 +89,15 @@ class FileBubbleState extends State<FileBubble> {
     } else if (flagStarted) {
       // in this case, the download was done in a previous application launch,
       // so we probably have to request an info lookup
-      var path = Provider.of<ProfileInfoState>(context).downloadFinalPath(widget.fileKey());
+      if (!Provider.of<ProfileInfoState>(context).downloadInterrupted(widget.fileKey()) ) {
-      if (path == null) {
+        wdgDecorations = Text(AppLocalizations.of(context)!.fileCheckingStatus + '...' + '\u202F');
-        wdgDecorations = Text('Checking download status...' + '\u202F');
         Provider.of<FlwtchState>(context, listen: false).cwtch.CheckDownloadStatus(Provider.of<ProfileInfoState>(context, listen: false).onion, widget.fileKey());
       } else {
-        wdgDecorations = Text('Saved to: ' + path + '\u202F');
+        var path = Provider.of<ProfileInfoState>(context).downloadFinalPath(widget.fileKey()) ?? "";
+        wdgDecorations = Column(
+            crossAxisAlignment: CrossAxisAlignment.start,
+            children:[Text(AppLocalizations.of(context)!.fileInterrupted + ': ' + path + '\u202F'),ElevatedButton(onPressed: _btnResume, child: Text('Verify/resume'))]
+        );
       }
     } else {
       wdgDecorations = Center(
@@ -167,6 +175,13 @@ class FileBubbleState extends State<FileBubble> {
     }
   }
 
+  void _btnResume() async {
+    var profileOnion = Provider.of<ProfileInfoState>(context, listen: false).onion;
+    var handle = Provider.of<MessageMetadata>(context, listen: false).senderHandle;
+    Provider.of<ProfileInfoState>(context, listen: false).downloadMarkResumed(widget.fileKey());
+    Provider.of<FlwtchState>(context, listen: false).cwtch.VerifyOrResumeDownload(profileOnion, handle, widget.fileKey());
+  }
+
   // Construct an file chrome for the sender
   Widget senderFileChrome(String chrome, String fileName, String rootHash, int fileSize) {
     return ListTile(