lib: Added i_stream_get_disconnect_reason()

src/lib/istream.c

@@ -97,6 +97,11 @@ const char *i_stream_get_error(struct istream *stream)
 	return strerror(stream->stream_errno);
 }
 
+const char *i_stream_get_disconnect_reason(struct istream *stream)
+{
+	return io_stream_get_disconnect_reason(stream, NULL);
+}
+
 void i_stream_close(struct istream *stream)
 {
 	i_stream_close_full(stream, TRUE);

src/lib/istream.h

@@ -77,6 +77,10 @@ int i_stream_get_fd(struct istream *stream);
 /* Returns error string for the last error. It also returns "EOF" in case there
    is no error, but eof is set. Otherwise it returns "<no error>". */
 const char *i_stream_get_error(struct istream *stream);
+/* Returns human-readable reason for why istream was disconnected. This can be
+   called to log the error when i_stream_read() returns -1. If there's an error
+   the output is identical to i_stream_get_error(). */
+const char *i_stream_get_disconnect_reason(struct istream *stream);
 
 /* Mark the stream and all of its parent streams closed. Any reads after this
    will return -1. The data already read can still be used. */