[evolution] Fix a runtime warning for zero-length attachments.

[Matthew Barnes <mbarnes src gnome org>]

commit 209168921d0e6cbc38c6856e45af7085696b961e
Author: Matthew Barnes <mbarnes redhat com>
Date:   Wed Jun 3 15:02:14 2009 -0400

    Fix a runtime warning for zero-length attachments.
---
 widgets/misc/e-attachment.c |   12 ++++++++----
 1 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/widgets/misc/e-attachment.c b/widgets/misc/e-attachment.c
index 35c377a..ba2811d 100644
--- a/widgets/misc/e-attachment.c
+++ b/widgets/misc/e-attachment.c
@@ -2430,10 +2430,14 @@ attachment_save_got_output_stream (SaveContext *save_context)
 	camel_data_wrapper_decode_to_stream (wrapper, stream);
 	camel_object_unref (stream);
 
-	/* Load the buffer into a GMemoryInputStream. */
-	input_stream = g_memory_input_stream_new_from_data (
-		buffer->data, (gssize) buffer->len,
-		(GDestroyNotify) g_free);
+	/* Load the buffer into a GMemoryInputStream.
+	 * But watch out for zero length MIME parts. */
+	input_stream = g_memory_input_stream_new ();
+	if (buffer->len > 0)
+		g_memory_input_stream_add_data (
+			G_MEMORY_INPUT_STREAM (input_stream),
+			buffer->data, (gssize) buffer->len,
+			(GDestroyNotify) g_free);
 	save_context->input_stream = input_stream;
 	save_context->total_num_bytes = (goffset) buffer->len;
 	g_byte_array_free (buffer, FALSE);