istream-hash: Allow seeking, but only after reading the hash.

diff --git a/src/lib/istream-hash.c b/src/lib/istream-hash.c
index 855e30b49c9c30d7f04068850fa76b6c4590131a..b54c66bc0ee2577f46cdd61c4175f7f9e6167e2a 100644 (file)
--- a/src/lib/istream-hash.c
+++ b/src/lib/istream-hash.c
@@ -38,6 +38,20 @@ i_stream_hash_read(struct istream_private *stream)
        return ret;
 }
 
+static void
+i_stream_hash_seek(struct istream_private *stream,
+                  uoff_t v_offset, bool mark ATTR_UNUSED)
+{
+       struct hash_istream *hstream = (struct hash_istream *)stream;
+
+       if (hstream->hash_context != NULL) {
+               /* we support seeking only after the hash is finished */
+               stream->istream.stream_errno = ESPIPE;
+       }
+       stream->istream.v_offset = v_offset;
+       stream->skip = stream->pos = 0;
+}
+
 struct istream *
 i_stream_create_hash(struct istream *input, const struct hash_method *method,
                     void *hash_context)
@@ -49,9 +63,10 @@ i_stream_create_hash(struct istream *input, const struct hash_method *method,
        hstream->istream.stream_size_passthrough = TRUE;
 
        hstream->istream.read = i_stream_hash_read;
+       hstream->istream.seek = i_stream_hash_seek;
 
        hstream->istream.istream.blocking = input->blocking;
-       hstream->istream.istream.seekable = FALSE;
+       hstream->istream.istream.seekable = input->seekable;
 
        hstream->method = method;
        hstream->hash_context = hash_context;