From d1921b4f2b6bc75e988e3bb81094de1d68995790 Mon Sep 17 00:00:00 2001
From: Greg Zaal <gregzzmail@gmail.com>
Date: Fri, 13 Oct 2023 11:51:58 +0200
Subject: [PATCH] Asset Browser: Add pre+post handlers to asset drag & drop

---
 source/blender/blenkernel/BKE_callbacks.h     |  2 ++
 .../blender/python/intern/bpy_app_handlers.cc |  3 ++
 .../windowmanager/intern/wm_dragdrop.cc       | 34 +++++++++++--------
 3 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/source/blender/blenkernel/BKE_callbacks.h b/source/blender/blenkernel/BKE_callbacks.h
index 4f52640d3d5..69e30ddf8d0 100644
--- a/source/blender/blenkernel/BKE_callbacks.h
+++ b/source/blender/blenkernel/BKE_callbacks.h
@@ -89,6 +89,8 @@ typedef enum {
   BKE_CB_EVT_SAVE_PRE,
   BKE_CB_EVT_SAVE_POST,
   BKE_CB_EVT_SAVE_POST_FAIL,
+  BKE_CB_EVT_ASSET_DROP_PRE,
+  BKE_CB_EVT_ASSET_DROP_POST,
   BKE_CB_EVT_UNDO_PRE,
   BKE_CB_EVT_UNDO_POST,
   BKE_CB_EVT_REDO_PRE,
diff --git a/source/blender/python/intern/bpy_app_handlers.cc b/source/blender/python/intern/bpy_app_handlers.cc
index c9a8dff2f17..ca6f19ec8ea 100644
--- a/source/blender/python/intern/bpy_app_handlers.cc
+++ b/source/blender/python/intern/bpy_app_handlers.cc
@@ -70,6 +70,9 @@ static PyStructSequence_Field app_cb_info_fields[] = {
     {"save_post", "on saving a blend file (after). " FILEPATH_SAVE_ARG},
     {"save_post_fail", "on failure to save a blend file (after). " FILEPATH_SAVE_ARG},
 
+    {"asset_drop_pre", "on dropping an asset from the asset browser (before). " FILEPATH_LOAD_ARG},
+    {"asset_drop_post", "on dropping an asset from the asset browser (after). "},
+
     {"undo_pre", "on loading an undo step (before)"},
     {"undo_post", "on loading an undo step (after)"},
     {"redo_pre", "on loading a redo step (before)"},
diff --git a/source/blender/windowmanager/intern/wm_dragdrop.cc b/source/blender/windowmanager/intern/wm_dragdrop.cc
index 3074ad9612b..3ce1ddd3d22 100644
--- a/source/blender/windowmanager/intern/wm_dragdrop.cc
+++ b/source/blender/windowmanager/intern/wm_dragdrop.cc
@@ -27,6 +27,7 @@
 
 #include "BIF_glutil.hh"
 
+#include "BKE_callbacks.h"
 #include "BKE_context.h"
 #include "BKE_global.h"
 #include "BKE_idprop.h"
@@ -629,28 +630,31 @@ ID *WM_drag_asset_id_import(const bContext *C, wmDragAsset *asset_drag, const in
   ViewLayer *view_layer = CTX_data_view_layer(C);
   View3D *view3d = CTX_wm_view3d(C);
 
+  BKE_callback_exec_string(bmain, BKE_CB_EVT_ASSET_DROP_PRE, blend_path.c_str());
+
+  ID *id = nullptr;
   switch (eAssetImportMethod(asset_drag->import_method)) {
     case ASSET_IMPORT_LINK:
-      return WM_file_link_datablock(bmain,
+      id = WM_file_link_datablock(bmain,
+                                  scene,
+                                  view_layer,
+                                  view3d,
+                                  blend_path.c_str(),
+                                  idtype,
+                                  name,
+                                  flag | (use_relative_path ? FILE_RELPATH : 0));
+    case ASSET_IMPORT_APPEND:
+      id = WM_file_append_datablock(bmain,
                                     scene,
                                     view_layer,
                                     view3d,
                                     blend_path.c_str(),
                                     idtype,
                                     name,
-                                    flag | (use_relative_path ? FILE_RELPATH : 0));
-    case ASSET_IMPORT_APPEND:
-      return WM_file_append_datablock(bmain,
-                                      scene,
-                                      view_layer,
-                                      view3d,
-                                      blend_path.c_str(),
-                                      idtype,
-                                      name,
-                                      flag | BLO_LIBLINK_APPEND_RECURSIVE |
-                                          BLO_LIBLINK_APPEND_ASSET_DATA_CLEAR);
+                                    flag | BLO_LIBLINK_APPEND_RECURSIVE |
+                                        BLO_LIBLINK_APPEND_ASSET_DATA_CLEAR);
     case ASSET_IMPORT_APPEND_REUSE:
-      return WM_file_append_datablock(
+      id = WM_file_append_datablock(
           G_MAIN,
           scene,
           view_layer,
@@ -662,8 +666,8 @@ ID *WM_drag_asset_id_import(const bContext *C, wmDragAsset *asset_drag, const in
               BLO_LIBLINK_APPEND_LOCAL_ID_REUSE | (use_relative_path ? FILE_RELPATH : 0));
   }
 
-  BLI_assert_unreachable();
-  return nullptr;
+  BKE_callback_exec_id(bmain, id, BKE_CB_EVT_ASSET_DROP_POST);
+  return id;
 }
 
 bool WM_drag_asset_will_import_linked(const wmDrag *drag)
-- 
2.30.2