Refactor: arrange transform convert functions in 'TransConvertTypeInfo'

Simplify the transform code by bundling the TransData creation, Data
recalculation, and special updates into a single struct.

So similar functions and parameters can be accessed without special
type checks.

Differential Revision: https://developer.blender.org/D15494

source/blender/editors/transform/transform.h

@@ -38,6 +38,7 @@ struct ReportList;
 struct Scene;
 struct ScrArea;
 struct SnapObjectContext;
+struct TransConvertTypeInfo;
 struct TransDataContainer;
 struct TransInfo;
 struct TransSnap;
@@ -204,37 +205,6 @@ typedef enum {
   HLP_TRACKBALL = 6,
 } eTHelpline;
 
-typedef enum {
-  TC_NONE = 0,
-  TC_ACTION_DATA,
-  TC_POSE,
-  TC_ARMATURE_VERTS,
-  TC_CURSOR_IMAGE,
-  TC_CURSOR_SEQUENCER,
-  TC_CURSOR_VIEW3D,
-  TC_CURVE_VERTS,
-  TC_GRAPH_EDIT_DATA,
-  TC_GPENCIL,
-  TC_LATTICE_VERTS,
-  TC_MASKING_DATA,
-  TC_MBALL_VERTS,
-  TC_MESH_VERTS,
-  TC_MESH_EDGES,
-  TC_MESH_SKIN,
-  TC_MESH_UV,
-  TC_MESH_VERT_CDATA,
-  TC_NLA_DATA,
-  TC_NODE_DATA,
-  TC_OBJECT,
-  TC_OBJECT_TEXSPACE,
-  TC_PAINT_CURVE_VERTS,
-  TC_PARTICLE_VERTS,
-  TC_SCULPT,
-  TC_SEQ_DATA,
-  TC_SEQ_IMAGE_DATA,
-  TC_TRACKING_DATA,
-} eTConvertType;
-
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -519,7 +489,7 @@ typedef struct TransInfo {
   int data_len_all;
 
   /** TODO: It should be a member of #TransDataContainer. */
-  eTConvertType data_type;
+  struct TransConvertTypeInfo *data_type;
 
   /** Current context/options for transform. */
   eTContext options;