--- a/src/lib/istream-seekable.h	Mon May 25 21:53:13 2009 -0400
+++ b/src/lib/istream-seekable.h	Mon May 25 22:18:55 2009 -0400
@@ -4,10 +4,13 @@
 /* Create a seekable stream from given NULL-terminated list of input streams.
    Try to keep it in memory, but use a temporary file if it's too large.
 
-   temp_prefix is used as path and filename prefix for creating the file.
-   It will be appended by PID, timestamp and 128 bits of weak randomness. */
+   When max_buffer_size is reached, fd_callback is called. It should return
+   the fd and path of the created file. Typically the callback would also
+   unlink the file before returning. */
 struct istream *
 i_stream_create_seekable(struct istream *input[],
-			 size_t max_buffer_size, const char *temp_prefix);
+			 size_t max_buffer_size,
+			 int (*fd_callback)(const char **path_r, void *context),
+			 void *context);
 
 #endif