[gegl] When doing in-place processing use it only once in the iterator

[Øyvind Kolås <ok src gnome org>]

commit 7a7eaad2356a9bc23ec0e03f91a74129f9b477e5
Author: �yvind Kolås <pippin gimp org>
Date:   Thu Nov 19 17:26:16 2009 +0000

    When doing in-place processing use it only once in the iterator

 gegl/operation/gegl-operation-filter.c         |    1 +
 gegl/operation/gegl-operation-point-composer.c |    6 +++++-
 gegl/operation/gegl-operation-point-filter.c   |    6 +++++-
 3 files changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/gegl/operation/gegl-operation-filter.c b/gegl/operation/gegl-operation-filter.c
index 8c85024..cf24d50 100644
--- a/gegl/operation/gegl-operation-filter.c
+++ b/gegl/operation/gegl-operation-filter.c
@@ -187,6 +187,7 @@ gboolean gegl_can_passthrough (GeglOperation       *operation,
                                GeglBuffer          *input,
                                const GeglRectangle *result)
 {
+  return FALSE;
   if (!input || 
       GEGL_IS_CACHE (input))
     return FALSE;
diff --git a/gegl/operation/gegl-operation-point-composer.c b/gegl/operation/gegl-operation-point-composer.c
index 0590cd3..3a973c9 100644
--- a/gegl/operation/gegl-operation-point-composer.c
+++ b/gegl/operation/gegl-operation-point-composer.c
@@ -146,7 +146,11 @@ gegl_operation_point_composer_process (GeglOperation       *operation,
   if ((result->width > 0) && (result->height > 0))
     {
       GeglBufferIterator *i = gegl_buffer_iterator_new (output, result, out_format, GEGL_BUFFER_WRITE);
-      gint read  = gegl_buffer_iterator_add (i, input,  result, in_format, GEGL_BUFFER_READ);
+      gint read;
+      if (input != output)
+        read  = gegl_buffer_iterator_add (i, input,  result, in_format, GEGL_BUFFER_READ);
+      else
+        read = 0;
 
       if (aux)
         {
diff --git a/gegl/operation/gegl-operation-point-filter.c b/gegl/operation/gegl-operation-point-filter.c
index 7d8c336..ba2b760 100644
--- a/gegl/operation/gegl-operation-point-filter.c
+++ b/gegl/operation/gegl-operation-point-filter.c
@@ -78,7 +78,11 @@ gegl_operation_point_filter_process (GeglOperation       *operation,
   if ((result->width > 0) && (result->height > 0))
     {
       GeglBufferIterator *i = gegl_buffer_iterator_new (output, result, out_format, GEGL_BUFFER_WRITE);
-      gint read  = gegl_buffer_iterator_add (i, input,  result, in_format, GEGL_BUFFER_READ);
+      gint read;
+      if (input != output)
+        read  = gegl_buffer_iterator_add (i, input,  result, in_format, GEGL_BUFFER_READ);
+      else
+        read = 0;
       while (gegl_buffer_iterator_next (i))
            point_filter_class->process (operation, i->data[read], i->data[0], i->length, &i->roi[0]);