Fetch on message structure exceptions

app/src/main/java/eu/faircode/email/Core.java

@@ -19,6 +19,11 @@ package eu.faircode.email;
     Copyright 2018-2021 by Marcel Bokhorst (M66B)
 */
 
+import static android.os.Process.THREAD_PRIORITY_BACKGROUND;
+import static androidx.core.app.NotificationCompat.DEFAULT_LIGHTS;
+import static androidx.core.app.NotificationCompat.DEFAULT_SOUND;
+import static javax.mail.Folder.READ_WRITE;
+
 import android.app.AlarmManager;
 import android.app.Notification;
 import android.app.NotificationChannel;
@@ -130,11 +135,6 @@ import javax.mail.search.SentDateTerm;
 
 import me.leolin.shortcutbadger.ShortcutBadger;
 
-import static android.os.Process.THREAD_PRIORITY_BACKGROUND;
-import static androidx.core.app.NotificationCompat.DEFAULT_LIGHTS;
-import static androidx.core.app.NotificationCompat.DEFAULT_SOUND;
-import static javax.mail.Folder.READ_WRITE;
-
 class Core {
     private static final int MAX_NOTIFICATION_DISPLAY = 10; // per group
     private static final int MAX_NOTIFICATION_COUNT = 100; // per group
@@ -3177,6 +3177,24 @@ class Core {
             IMAPStore istore, IMAPFolder ifolder, MimeMessage imessage,
             boolean browsed, boolean download,
             List<EntityRule> rules, State state, SyncStats stats) throws MessagingException, IOException {
+        try {
+            return _synchronizeMessage(context, account, folder,
+                    istore, ifolder, imessage,
+                    browsed, download, rules, state, stats);
+        } catch (MessageHelper.MessagingStructureException ex) {
+            Log.e(ex);
+            long uid = ifolder.getUID(imessage);
+            EntityOperation.queue(context, folder, EntityOperation.FETCH, uid);
+            return null;
+        }
+    }
+
+    private static EntityMessage _synchronizeMessage(
+            Context context,
+            EntityAccount account, EntityFolder folder,
+            IMAPStore istore, IMAPFolder ifolder, MimeMessage imessage,
+            boolean browsed, boolean download,
+            List<EntityRule> rules, State state, SyncStats stats) throws MessagingException, IOException {
         DB db = DB.getInstance(context);
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
         boolean download_headers = prefs.getBoolean("download_headers", false);

app/src/main/java/eu/faircode/email/MessageHelper.java

@@ -19,12 +19,15 @@ package eu.faircode.email;
     Copyright 2018-2021 by Marcel Bokhorst (M66B)
 */
 
+import static android.system.OsConstants.ENOSPC;
+
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.net.Uri;
 import android.system.ErrnoException;
 import android.text.TextUtils;
 
+import androidx.annotation.Nullable;
 import androidx.core.net.MailTo;
 import androidx.documentfile.provider.DocumentFile;
 import androidx.preference.PreferenceManager;
@@ -109,8 +112,6 @@ import javax.mail.internet.ParseException;
 import biweekly.Biweekly;
 import biweekly.ICalendar;
 
-import static android.system.OsConstants.ENOSPC;
-
 public class MessageHelper {
     private boolean ensuredEnvelope = false;
     private boolean ensuredHeaders = false;
@@ -2509,11 +2510,8 @@ public class MessageHelper {
                                 break;
                             }
                         }
-                    } else {
+                    } else
-                        String msg = "Multipart=" + (content == null ? null : content.getClass().getName());
+                        throw new MessagingStructureException(content);
-                        Log.e(msg);
-                        throw new MessagingException(msg);
-                    }
                 }
 
                 if (part.isMimeType("multipart/signed")) {
@@ -2557,11 +2555,8 @@ public class MessageHelper {
                                     sb.append(' ').append(i).append('=').append(multipart.getBodyPart(i).getContentType());
                                 Log.e(sb.toString());
                             }
-                        } else {
+                        } else
-                            String msg = "Multipart=" + (content == null ? null : content.getClass().getName());
+                            throw new MessagingStructureException(content);
-                            Log.e(msg);
-                            throw new MessagingException(msg);
-                        }
                     } else
                         Log.e(ct.toString());
                 } else if (part.isMimeType("multipart/encrypted")) {
@@ -2582,11 +2577,8 @@ public class MessageHelper {
                                     sb.append(' ').append(i).append('=').append(multipart.getBodyPart(i).getContentType());
                                 Log.e(sb.toString());
                             }
-                        } else {
+                        } else
-                            String msg = "Multipart=" + (content == null ? null : content.getClass().getName());
+                            throw new MessagingStructureException(content);
-                            Log.e(msg);
-                            throw new MessagingException(msg);
-                        }
                     } else
                         Log.e(ct.toString());
                 } else if (part.isMimeType("application/pkcs7-mime") ||
@@ -2661,11 +2653,8 @@ public class MessageHelper {
                 Object content = part.getContent(); // Should always be Multipart
                 if (content instanceof Multipart)
                     multipart = (Multipart) part.getContent();
-                else {
+                else
-                    String msg = "Multipart=" + (content == null ? null : content.getClass().getName());
+                    throw new MessagingStructureException(content);
-                    Log.e(msg);
-                    throw new MessagingException(msg);
-                }
 
                 boolean other = false;
                 List<Part> plain = new ArrayList<>();
@@ -3049,4 +3038,20 @@ public class MessageHelper {
 
         return values;
     }
+
+    static class MessagingStructureException extends MessagingException {
+        private String className;
+
+        MessagingStructureException(Object content) {
+            super();
+            if (content != null)
+                this.className = content.getClass().getName();
+        }
+
+        @Nullable
+        @Override
+        public String getMessage() {
+            return className;
+        }
+    }
 }