[gegl] buffer: fix single-pixel gegl_buffer_get()

[N/A <ell src gnome org>]

commit 9102b31f5152d18861f1a4feacb45a4b94163cda
Author: Ell <ell_se yahoo com>
Date:   Thu Mar 15 05:10:02 2018 -0400

    buffer: fix single-pixel gegl_buffer_get()
    
    In _gegl_buffer_get_unlocked(), move the assignment of the buffer's
    format to the 'format' parameter, in case it's NULL, to the
    beginning of the function.  In particular, move it before the call
    to gegl_buffer_get_pixel(), which can segfault if called with a
    NULL format.

 gegl/buffer/gegl-buffer-access.c |   16 ++++++----------
 1 files changed, 6 insertions(+), 10 deletions(-)
---
diff --git a/gegl/buffer/gegl-buffer-access.c b/gegl/buffer/gegl-buffer-access.c
index 52fc23c..bb2d0eb 100644
--- a/gegl/buffer/gegl-buffer-access.c
+++ b/gegl/buffer/gegl-buffer-access.c
@@ -150,7 +150,7 @@ gegl_buffer_get_pixel (GeglBuffer     *buffer,
         gint px_size = babl_format_get_bytes_per_pixel (buffer->soft_format);
         guchar    *tp = gegl_tile_get_data (tile) + (offsety * tile_width + offsetx) * px_size;
 
-       if (format && format != buffer->soft_format)
+       if (format != buffer->soft_format)
           {
             babl_process (babl_fish (buffer->soft_format, format), tp, buf, 1);
           }
@@ -1995,12 +1995,16 @@ _gegl_buffer_get_unlocked (GeglBuffer          *buffer,
 {
   GeglAbyssPolicy repeat_mode = flags & 0x7; /* mask off interpolation from repeat mode part of flags */
 
+  g_return_if_fail (scale > 0.0f);
+
+  if (format == NULL)
+    format = buffer->soft_format;
+
   if (gegl_cl_is_accelerated ())
     {
       gegl_buffer_cl_cache_flush (buffer, rect);
     }
 
-
   if (scale == 1.0 &&
       rect &&
       rect->width == 1)
@@ -2012,9 +2016,6 @@ _gegl_buffer_get_unlocked (GeglBuffer          *buffer,
       }
     else
       {
-        if (format == NULL)
-          format = buffer->soft_format;
-
         if (buffer->soft_format == format ||
             rowstride != babl_format_get_bytes_per_pixel (format))
         {
@@ -2036,11 +2037,6 @@ _gegl_buffer_get_unlocked (GeglBuffer          *buffer,
     return;
   }
 
-  g_return_if_fail (scale > 0.0f);
-
-  if (format == NULL)
-    format = buffer->soft_format;
-
   if (!rect && GEGL_FLOAT_EQUAL (scale, 1.0))
     {
       gegl_buffer_iterate_read_dispatch (buffer, &buffer->extent, dest_buf,