patch [#25490] Fix for [#22096] Blender tries to open non-blend file

from Alexander Kuznetsov (alexk) with edits.

From the report:
Blender assumed that all files are .blend as retval = 0;

Now retval is initialized as file cannot be open (-1) for gzopen fail and directory case
retval = -2; is defined for not supported formats
This must be assigned before #ifdef WITH_PYTHON because this part can be missing
Finally retval = 0; if it is a .blend file

---
also made other edits.

- exotic.c's blend header checking was sloppy, didn't check data was actually read, only checked first 4 bytes and had a check for "blend.gz" extension which is unnecessary.
- use defines to help readability for BKE_read_exotic & BKE_read_file return values.
- no need to check for a NULL pointer before calling BKE_reportf(). (will just print to the console)
- print better reports when the file fails to load.

1 files changed, 7 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_exotic.h b/source/blender/blenkernel/BKE_exotic.h
index 553e62ba578..ad59cd9c0a8 100644
--- a/source/blender/blenkernel/BKE_exotic.h
+++ b/source/blender/blenkernel/BKE_exotic.h
@@ -42,6 +42,13 @@ struct Scene;
  */
 int BKE_read_exotic(struct Scene *scene, const char *name);
 
+/* return codes */
+#define BKE_READ_EXOTIC_FAIL_PATH		-3 /* file format is not supported */
+#define BKE_READ_EXOTIC_FAIL_FORMAT		-2 /* file format is not supported */
+#define BKE_READ_EXOTIC_FAIL_OPEN		-1 /* Can't open the file */
+#define BKE_READ_EXOTIC_OK_BLEND		 0 /* .blend file */
+#define BKE_READ_EXOTIC_OK_OTHER		 1 /* other supported formats */
+
 void write_dxf(struct Scene *scene, char *str);
 void write_stl(struct Scene *scene, char *str);