Created attachment 263775 [details] [review]
gio: Update GMemoryOutputStream length after truncate

For GMemoryOutputStream, update valid_len when truncating so that
g_memory_output_stream_get_data_size () returns the correct result.

Review of attachment 263775 [details] [review]:

::: gio/tests/memory-output-stream.c
@@ +55,3 @@
+  g_seekable_truncate (G_SEEKABLE (mo), 8192, NULL, &error);
+  g_assert_cmpint (g_memory_output_stream_get_data_size (G_MEMORY_OUTPUT_STREAM (mo)), ==, 8192);
+

Do we guarantee that the extra data reads as zeros ? If yes, would be good to test that too.

See bug 684842 about recent activity here.

Particularly, be careful about the fixed-sized case.  It looks like array_resize() will error out in that case anyway, so I think this is probably fine.

As for reading extra zero bytes in the non-fixed-sized case, I think that would indeed be consistent with the view of a seekable non-fixed-size output stream behaving similarly to a file.  Probably worth putting under a test.

Attachment 263775 [details] pushed as 3b9ad6e - gio: Update GMemoryOutputStream length after truncate