Py-Driver: add 'self' option

Drivers can use this to refer to the data which the driver is applied to,
useful for objects, bones, to avoid having to create a variable pointing to its self.

source/blender/python/BPY_extern.h

@@ -32,6 +32,7 @@
 #ifndef __BPY_EXTERN_H__
 #define __BPY_EXTERN_H__
 
+struct PathResolvedRNA;
 struct Text; /* defined in DNA_text_types.h */
 struct ID; /* DNA_ID.h */
 struct Object; /* DNA_object_types.h */
@@ -85,7 +86,7 @@ void	BPY_modules_load_user(struct bContext *C);
 void	BPY_app_handlers_reset(const short do_all);
 
 void	BPY_driver_reset(void);
-float	BPY_driver_exec(struct ChannelDriver *driver, const float evaltime);
+float	BPY_driver_exec(struct PathResolvedRNA *anim_rna, struct ChannelDriver *driver, const float evaltime);
 
 void	BPY_DECREF(void *pyob_ptr);	/* Py_DECREF() */
 void	BPY_DECREF_RNA_INVALIDATE(void *pyob_ptr);

source/blender/python/intern/bpy_driver.c

@@ -120,6 +120,22 @@ static void bpy_pydriver_update_dict(const float evaltime)
 	}
 }
 
+static PyObject *bpy_pydriver_InternStr__self = NULL;
+
+static void bpy_pydriver_update_dict_self(struct PathResolvedRNA *anim_rna)
+{
+	if (bpy_pydriver_InternStr__self == NULL) {
+		bpy_pydriver_InternStr__self = PyUnicode_FromString("self");
+	}
+
+	PyObject *item = pyrna_driver_self_from_anim_rna(anim_rna);
+	PyDict_SetItem(bpy_pydriver_Dict,
+	               bpy_pydriver_InternStr__self,
+	               item);
+	Py_DECREF(item);
+
+}
+
 /* Update function, it gets rid of pydrivers global dictionary, forcing
  * BPY_driver_exec to recreate it. This function is used to force
  * reloading the Blender text module "pydrivers.py", if available, so
@@ -174,7 +190,7 @@ static void pydriver_error(ChannelDriver *driver)
  * now release the GIL on python operator execution instead, using
  * PyEval_SaveThread() / PyEval_RestoreThread() so we don't lock up blender.
  */
-float BPY_driver_exec(ChannelDriver *driver, const float evaltime)
+float BPY_driver_exec(struct PathResolvedRNA *anim_rna, ChannelDriver *driver, const float evaltime)
 {
 	PyObject *driver_vars = NULL;
 	PyObject *retval = NULL;
@@ -226,6 +242,9 @@ float BPY_driver_exec(ChannelDriver *driver, const float evaltime)
 	/* update global namespace */
 	bpy_pydriver_update_dict(evaltime);
 
+	if (driver->flag & DRIVER_FLAG_USE_SELF) {
+		bpy_pydriver_update_dict_self(anim_rna);
+	}
 
 	if (driver->expr_comp == NULL)
 		driver->flag |= DRIVER_FLAG_RECOMPILE;

source/blender/python/intern/bpy_driver.h

@@ -28,12 +28,13 @@
 #define __BPY_DRIVER_H__
 
 struct ChannelDriver;
+struct PathResolvedRNA;
 
 int bpy_pydriver_create_dict(void);
 extern PyObject *bpy_pydriver_Dict;
 
 /* externals */
-float BPY_driver_exec(struct ChannelDriver *driver, const float evaltime);
+float BPY_driver_exec(struct PathResolvedRNA *anim_rna, struct ChannelDriver *driver, const float evaltime);
 void BPY_driver_reset(void);
 
 #endif  /* __BPY_DRIVER_H__ */

source/blender/python/intern/bpy_rna_driver.c

@@ -77,3 +77,8 @@ PyObject *pyrna_driver_get_variable_value(
 
 	return driver_arg;
 }
+
+PyObject *pyrna_driver_self_from_anim_rna(struct PathResolvedRNA *anim_rna)
+{
+	return pyrna_struct_CreatePyObject(&anim_rna->ptr);
+}

source/blender/python/intern/bpy_rna_driver.h

@@ -27,7 +27,9 @@
 
 struct ChannelDriver;
 struct DriverTarget;
+struct PathResolvedRNA;
 
 PyObject *pyrna_driver_get_variable_value(struct ChannelDriver *driver, struct DriverTarget *dtar);
+PyObject *pyrna_driver_self_from_anim_rna(struct PathResolvedRNA *anim_rna);
 
 #endif  /* __BPY_RNA_DRIVER_H__ */