Added method for deleting metadata.

briar-core/src/org/briarproject/db/Database.java

@@ -225,6 +225,13 @@ interface Database<T> {
 	 */
 	void deleteMessage(T txn, MessageId m) throws DbException;
 
+	/**
+	 * Deletes any metadata associated with the given message.
+	 * <p>
+	 * Locking: write.
+	 */
+	void deleteMessageMetadata(T txn, MessageId m) throws DbException;
+
 	/**
 	 * Returns the contact with the given ID.
 	 * <p>

briar-core/src/org/briarproject/db/DatabaseComponentImpl.java

@@ -310,6 +310,23 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		}
 	}
 
+	public void deleteMessageMetadata(MessageId m) throws DbException {
+		lock.writeLock().lock();
+		try {
+			T txn = db.startTransaction();
+			try {
+				if (!db.containsMessage(txn, m))
+					throw new NoSuchMessageException();
+				db.deleteMessageMetadata(txn, m);
+			} catch (DbException e) {
+				db.abortTransaction(txn);
+				throw e;
+			}
+		} finally {
+			lock.writeLock().unlock();
+		}
+	}
+
 	public Ack generateAck(ContactId c, int maxMessages) throws DbException {
 		Collection<MessageId> ids;
 		lock.writeLock().lock();

briar-core/src/org/briarproject/db/JdbcDatabase.java

@@ -949,6 +949,22 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	public void deleteMessageMetadata(Connection txn, MessageId m)
+			throws DbException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "DELETE FROM messageMetadata WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			int affected = ps.executeUpdate();
+			if (affected < 0) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	public Contact getContact(Connection txn, ContactId c) throws DbException {
 		PreparedStatement ps = null;
 		ResultSet rs = null;