Merge branch '8.5'

ChangeLog

@@ -14,6 +14,7 @@
 - raise b64 limit to allow for huge profiles (thanks jaume)
 - fix error return in blob save (thanks jaume)
 - tag vipsprofile as py2 (thanks ioquatix)
+- don't cache thumbnail (thanks tomasc)
 
 23/4/17 started 8.5.5
 - doc polishing

libvips/resample/thumbnail.c

@@ -7,6 +7,8 @@
  * 	- add @size parameter
  * 4/5/17
  * 	- add FORCE
+ * 29/5/17
+ * 	- don't cache (thanks tomasc)
  */
 
 /*
@@ -548,6 +550,7 @@ vips_thumbnail_class_init( VipsThumbnailClass *class )
 {
 	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
 	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
 
 	gobject_class->dispose = vips_thumbnail_dispose;
 	gobject_class->finalize = vips_thumbnail_finalize;
@@ -558,6 +561,11 @@ vips_thumbnail_class_init( VipsThumbnailClass *class )
 	vobject_class->description = _( "thumbnail generation" );
 	vobject_class->build = vips_thumbnail_build;
 
+	/* We mustn't cache these calls, since we open the file or buffer in 
+	 * sequential mode.
+	 */
+	operation_class->flags = VIPS_OPERATION_NOCACHE;
+
 	VIPS_ARG_IMAGE( class, "out", 2, 
 		_( "Output" ), 
 		_( "Output image" ),