Lookup by hash (experimental)

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

@@ -2068,6 +2068,17 @@ class Core {
         // Find message by uid (fast, no headers required)
         EntityMessage message = db.message().getMessageByUid(folder.id, uid);
 
+        // Find message by internal hash (slow, headers required)
+        // - pre moved messages
+        if (message == null) {
+            String hash = helper.getHash();
+            List<EntityMessage> existing = db.message().getMessagesByHash(folder.id, hash);
+            if (existing != null && existing.size() == 1) {
+                Log.i(folder.name + " found by hash=" + hash);
+                message = existing.get(0);
+            }
+        }
+
         // Find message by Message-ID (slow, headers required)
         // - messages in inbox have same id as message sent to self
         // - messages in archive have same id as original

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

@@ -60,7 +60,7 @@ import io.requery.android.database.sqlite.SQLiteDatabase;
 // https://developer.android.com/topic/libraries/architecture/room.html
 
 @Database(
-        version = 152,
+        version = 153,
         entities = {
                 EntityIdentity.class,
                 EntityAccount.class,
@@ -1444,6 +1444,13 @@ public abstract class DB extends RoomDatabase {
                         Log.i("DB migration from version " + startVersion + " to " + endVersion);
                         db.execSQL("ALTER TABLE `message` ADD COLUMN `hash` TEXT");
                     }
+                })
+                .addMigrations(new Migration(152, 153) {
+                    @Override
+                    public void migrate(@NonNull SupportSQLiteDatabase db) {
+                        Log.i("DB migration from version " + startVersion + " to " + endVersion);
+                        db.execSQL("CREATE INDEX IF NOT EXISTS `index_message_folder_hash` ON `message` (`folder`, `hash`)");
+                    }
                 });
     }
 

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

@@ -324,6 +324,11 @@ public interface DaoMessage {
             " AND msgid = :msgid")
     List<EntityMessage> getMessagesByMsgId(long account, String msgid);
 
+    @Query("SELECT * FROM message" +
+            " WHERE folder = :folder" +
+            " AND hash = :hash")
+    List<EntityMessage> getMessagesByHash(long folder, String hash);
+
     @Query("SELECT * FROM message" +
             " WHERE account = :account" +
             " AND (id = :id OR msgid = :msgid)")

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

@@ -63,6 +63,7 @@ import static androidx.room.ForeignKey.SET_NULL;
                 @Index(value = {"folder"}),
                 @Index(value = {"identity"}),
                 @Index(value = {"folder", "uid"}, unique = true),
+                @Index(value = {"folder", "hash"}),
                 @Index(value = {"msgid"}),
                 @Index(value = {"thread"}),
                 @Index(value = {"sender"}),