Cleanup: Move remaning node editor files to C++

Differential Revision: https://developer.blender.org/D13200

1 files changed, 1081 insertions, 0 deletions

diff --git a/source/blender/editors/space_node/space_node.cc b/source/blender/editors/space_node/space_node.cc
new file mode 100644
index 00000000000..53592aef98b
--- /dev/null
+++ b/source/blender/editors/space_node/space_node.cc
@@ -0,0 +1,1081 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2008 Blender Foundation.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup spnode
+ */
+
+#include "DNA_gpencil_types.h"
+#include "DNA_light_types.h"
+#include "DNA_material_types.h"
+#include "DNA_node_types.h"
+#include "DNA_world_types.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_math.h"
+
+#include "BKE_context.h"
+#include "BKE_lib_id.h"
+#include "BKE_node.h"
+#include "BKE_screen.h"
+
+#include "ED_node.h"
+#include "ED_render.h"
+#include "ED_screen.h"
+#include "ED_space_api.h"
+
+#include "UI_resources.h"
+#include "UI_view2d.h"
+
+#include "RNA_access.h"
+#include "RNA_define.h"
+#include "RNA_enum_types.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+#include "node_intern.hh" /* own include */
+
+/* ******************** tree path ********************* */
+
+void ED_node_tree_start(SpaceNode *snode, bNodeTree *ntree, ID *id, ID *from)
+{
+  LISTBASE_FOREACH_MUTABLE (bNodeTreePath *, path, &snode->treepath) {
+    MEM_freeN(path);
+  }
+  BLI_listbase_clear(&snode->treepath);
+
+  if (ntree) {
+    bNodeTreePath *path = (bNodeTreePath *)MEM_callocN(sizeof(bNodeTreePath), "node tree path");
+    path->nodetree = ntree;
+    path->parent_key = NODE_INSTANCE_KEY_BASE;
+
+    /* copy initial offset from bNodeTree */
+    copy_v2_v2(path->view_center, ntree->view_center);
+
+    if (id) {
+      BLI_strncpy(path->display_name, id->name + 2, sizeof(path->display_name));
+    }
+
+    BLI_addtail(&snode->treepath, path);
+
+    if (ntree->type != NTREE_GEOMETRY) {
+      /* This can probably be removed for all node tree types. It mainly exists because it was not
+       * possible to store id references in custom properties. Also see T36024. I don't want to
+       * remove it for all tree types in bcon3 though. */
+      id_us_ensure_real(&ntree->id);
+    }
+  }
+
+  /* update current tree */
+  snode->nodetree = snode->edittree = ntree;
+  snode->id = id;
+  snode->from = from;
+
+  ED_node_set_active_viewer_key(snode);
+
+  WM_main_add_notifier(NC_SCENE | ND_NODES, nullptr);
+}
+
+void ED_node_tree_push(SpaceNode *snode, bNodeTree *ntree, bNode *gnode)
+{
+  bNodeTreePath *path = (bNodeTreePath *)MEM_callocN(sizeof(bNodeTreePath), "node tree path");
+  bNodeTreePath *prev_path = (bNodeTreePath *)snode->treepath.last;
+  path->nodetree = ntree;
+  if (gnode) {
+    if (prev_path) {
+      path->parent_key = BKE_node_instance_key(prev_path->parent_key, prev_path->nodetree, gnode);
+    }
+    else {
+      path->parent_key = NODE_INSTANCE_KEY_BASE;
+    }
+
+    BLI_strncpy(path->node_name, gnode->name, sizeof(path->node_name));
+    BLI_strncpy(path->display_name, gnode->name, sizeof(path->display_name));
+  }
+  else {
+    path->parent_key = NODE_INSTANCE_KEY_BASE;
+  }
+
+  /* copy initial offset from bNodeTree */
+  copy_v2_v2(path->view_center, ntree->view_center);
+
+  BLI_addtail(&snode->treepath, path);
+
+  id_us_ensure_real(&ntree->id);
+
+  /* update current tree */
+  snode->edittree = ntree;
+
+  ED_node_set_active_viewer_key(snode);
+
+  WM_main_add_notifier(NC_SCENE | ND_NODES, nullptr);
+}
+
+void ED_node_tree_pop(SpaceNode *snode)
+{
+  bNodeTreePath *path = (bNodeTreePath *)snode->treepath.last;
+
+  /* don't remove root */
+  if (path == snode->treepath.first) {
+    return;
+  }
+
+  BLI_remlink(&snode->treepath, path);
+  MEM_freeN(path);
+
+  /* update current tree */
+  path = (bNodeTreePath *)snode->treepath.last;
+  snode->edittree = path->nodetree;
+
+  ED_node_set_active_viewer_key(snode);
+
+  /* listener updates the View2D center from edittree */
+  WM_main_add_notifier(NC_SCENE | ND_NODES, nullptr);
+}
+
+int ED_node_tree_depth(SpaceNode *snode)
+{
+  return BLI_listbase_count(&snode->treepath);
+}
+
+bNodeTree *ED_node_tree_get(SpaceNode *snode, int level)
+{
+  bNodeTreePath *path;
+  int i;
+  for (path = (bNodeTreePath *)snode->treepath.last, i = 0; path; path = path->prev, i++) {
+    if (i == level) {
+      return path->nodetree;
+    }
+  }
+  return nullptr;
+}
+
+int ED_node_tree_path_length(SpaceNode *snode)
+{
+  int length = 0;
+  int i = 0;
+  LISTBASE_FOREACH_INDEX (bNodeTreePath *, path, &snode->treepath, i) {
+    length += strlen(path->display_name);
+    if (i > 0) {
+      length += 1; /* for separator char */
+    }
+  }
+  return length;
+}
+
+void ED_node_tree_path_get(SpaceNode *snode, char *value)
+{
+  int i = 0;
+
+  value[0] = '\0';
+  LISTBASE_FOREACH_INDEX (bNodeTreePath *, path, &snode->treepath, i) {
+    if (i == 0) {
+      strcpy(value, path->display_name);
+      value += strlen(path->display_name);
+    }
+    else {
+      sprintf(value, "/%s", path->display_name);
+      value += strlen(path->display_name) + 1;
+    }
+  }
+}
+
+void ED_node_set_active_viewer_key(SpaceNode *snode)
+{
+  bNodeTreePath *path = (bNodeTreePath *)snode->treepath.last;
+  if (snode->nodetree && path) {
+    snode->nodetree->active_viewer_key = path->parent_key;
+  }
+}
+
+void space_node_group_offset(SpaceNode *snode, float *x, float *y)
+{
+  bNodeTreePath *path = (bNodeTreePath *)snode->treepath.last;
+
+  if (path && path->prev) {
+    float dcenter[2];
+    sub_v2_v2v2(dcenter, path->view_center, path->prev->view_center);
+    *x = dcenter[0];
+    *y = dcenter[1];
+  }
+  else {
+    *x = *y = 0.0f;
+  }
+}
+
+/* ******************** default callbacks for node space ***************** */
+
+static SpaceLink *node_create(const ScrArea *UNUSED(area), const Scene *UNUSED(scene))
+{
+  SpaceNode *snode = (SpaceNode *)MEM_callocN(sizeof(SpaceNode), "initnode");
+  snode->spacetype = SPACE_NODE;
+
+  snode->flag = SNODE_SHOW_GPENCIL | SNODE_USE_ALPHA;
+  snode->overlay.flag |= SN_OVERLAY_SHOW_OVERLAYS;
+  snode->overlay.flag |= SN_OVERLAY_SHOW_WIRE_COLORS;
+
+  /* backdrop */
+  snode->zoom = 1.0f;
+
+  /* select the first tree type for valid type */
+  NODE_TREE_TYPES_BEGIN (treetype) {
+    strcpy(snode->tree_idname, treetype->idname);
+    break;
+  }
+  NODE_TREE_TYPES_END;
+
+  /* header */
+  ARegion *region = (ARegion *)MEM_callocN(sizeof(ARegion), "header for node");
+
+  BLI_addtail(&snode->regionbase, region);
+  region->regiontype = RGN_TYPE_HEADER;
+  region->alignment = (U.uiflag & USER_HEADER_BOTTOM) ? RGN_ALIGN_BOTTOM : RGN_ALIGN_TOP;
+
+  /* buttons/list view */
+  region = (ARegion *)MEM_callocN(sizeof(ARegion), "buttons for node");
+
+  BLI_addtail(&snode->regionbase, region);
+  region->regiontype = RGN_TYPE_UI;
+  region->alignment = RGN_ALIGN_RIGHT;
+
+  /* toolbar */
+  region = (ARegion *)MEM_callocN(sizeof(ARegion), "node tools");
+
+  BLI_addtail(&snode->regionbase, region);
+  region->regiontype = RGN_TYPE_TOOLS;
+  region->alignment = RGN_ALIGN_LEFT;
+
+  region->flag = RGN_FLAG_HIDDEN;
+
+  /* main region */
+  region = (ARegion *)MEM_callocN(sizeof(ARegion), "main region for node");
+
+  BLI_addtail(&snode->regionbase, region);
+  region->regiontype = RGN_TYPE_WINDOW;
+
+  region->v2d.tot.xmin = -12.8f * U.widget_unit;
+  region->v2d.tot.ymin = -12.8f * U.widget_unit;
+  region->v2d.tot.xmax = 38.4f * U.widget_unit;
+  region->v2d.tot.ymax = 38.4f * U.widget_unit;
+
+  region->v2d.cur = region->v2d.tot;
+
+  region->v2d.min[0] = 1.0f;
+  region->v2d.min[1] = 1.0f;
+
+  region->v2d.max[0] = 32000.0f;
+  region->v2d.max[1] = 32000.0f;
+
+  region->v2d.minzoom = 0.09f;
+  region->v2d.maxzoom = 2.31f;
+
+  region->v2d.scroll = (V2D_SCROLL_RIGHT | V2D_SCROLL_BOTTOM);
+  region->v2d.keepzoom = V2D_LIMITZOOM | V2D_KEEPASPECT;
+  region->v2d.keeptot = 0;
+
+  return (SpaceLink *)snode;
+}
+
+static void node_free(SpaceLink *sl)
+{
+  SpaceNode *snode = (SpaceNode *)sl;
+
+  LISTBASE_FOREACH_MUTABLE (bNodeTreePath *, path, &snode->treepath) {
+    MEM_freeN(path);
+  }
+
+  MEM_SAFE_FREE(snode->runtime);
+}
+
+/* spacetype; init callback */
+static void node_init(struct wmWindowManager *UNUSED(wm), ScrArea *area)
+{
+  SpaceNode *snode = (SpaceNode *)area->spacedata.first;
+
+  if (snode->runtime == nullptr) {
+    snode->runtime = (SpaceNode_Runtime *)MEM_callocN(sizeof(SpaceNode_Runtime), __func__);
+  }
+}
+
+static void node_area_listener(const wmSpaceTypeListenerParams *params)
+{
+  ScrArea *area = params->area;
+  wmNotifier *wmn = params->notifier;
+
+  /* NOTE: #ED_area_tag_refresh will re-execute compositor. */
+  SpaceNode *snode = (SpaceNode *)area->spacedata.first;
+  /* shaderfrom is only used for new shading nodes, otherwise all shaders are from objects */
+  short shader_type = snode->shaderfrom;
+
+  /* preview renders */
+  switch (wmn->category) {
+    case NC_SCENE:
+      switch (wmn->data) {
+        case ND_NODES: {
+          ARegion *region = BKE_area_find_region_type(area, RGN_TYPE_WINDOW);
+          bNodeTreePath *path = (bNodeTreePath *)snode->treepath.last;
+          /* shift view to node tree center */
+          if (region && path) {
+            UI_view2d_center_set(&region->v2d, path->view_center[0], path->view_center[1]);
+          }
+
+          ED_area_tag_refresh(area);
+          break;
+        }
+        case ND_FRAME:
+          ED_area_tag_refresh(area);
+          break;
+        case ND_COMPO_RESULT:
+          ED_area_tag_redraw(area);
+          break;
+        case ND_TRANSFORM_DONE:
+          if (ED_node_is_compositor(snode)) {
+            if (snode->flag & SNODE_AUTO_RENDER) {
+              snode->runtime->recalc = true;
+              ED_area_tag_refresh(area);
+            }
+          }
+          break;
+        case ND_LAYER_CONTENT:
+          ED_area_tag_refresh(area);
+          break;
+      }
+      break;
+
+    /* future: add ID checks? */
+    case NC_MATERIAL:
+      if (ED_node_is_shader(snode)) {
+        if (wmn->data == ND_SHADING) {
+          ED_area_tag_refresh(area);
+        }
+        else if (wmn->data == ND_SHADING_DRAW) {
+          ED_area_tag_refresh(area);
+        }
+        else if (wmn->data == ND_SHADING_LINKS) {
+          ED_area_tag_refresh(area);
+        }
+        else if (wmn->action == NA_ADDED && snode->edittree) {
+          nodeSetActiveID(snode->edittree, ID_MA, (ID *)wmn->reference);
+        }
+      }
+      break;
+    case NC_TEXTURE:
+      if (ED_node_is_shader(snode) || ED_node_is_texture(snode)) {
+        if (wmn->data == ND_NODES) {
+          ED_area_tag_refresh(area);
+        }
+      }
+      break;
+    case NC_WORLD:
+      if (ED_node_is_shader(snode) && shader_type == SNODE_SHADER_WORLD) {
+        ED_area_tag_refresh(area);
+      }
+      break;
+    case NC_OBJECT:
+      if (ED_node_is_shader(snode)) {
+        if (wmn->data == ND_OB_SHADING) {
+          ED_area_tag_refresh(area);
+        }
+      }
+      else if (ED_node_is_geometry(snode)) {
+        /* Rather strict check: only redraw when the reference matches the current editor's ID. */
+        if (wmn->data == ND_MODIFIER) {
+          if (wmn->reference == snode->id || snode->id == nullptr) {
+            ED_area_tag_refresh(area);
+          }
+        }
+      }
+      break;
+    case NC_SPACE:
+      if (wmn->data == ND_SPACE_NODE) {
+        ED_area_tag_refresh(area);
+      }
+      else if (wmn->data == ND_SPACE_NODE_VIEW) {
+        ED_area_tag_redraw(area);
+      }
+      break;
+    case NC_NODE:
+      if (wmn->action == NA_EDITED) {
+        ED_area_tag_refresh(area);
+      }
+      else if (wmn->action == NA_SELECTED) {
+        ED_area_tag_redraw(area);
+      }
+      break;
+    case NC_SCREEN:
+      switch (wmn->data) {
+        case ND_ANIMPLAY:
+          ED_area_tag_refresh(area);
+          break;
+      }
+      break;
+    case NC_MASK:
+      if (wmn->action == NA_EDITED) {
+        if (snode->nodetree && snode->nodetree->type == NTREE_COMPOSIT) {
+          ED_area_tag_refresh(area);
+        }
+      }
+      break;
+
+    case NC_IMAGE:
+      if (wmn->action == NA_EDITED) {
+        if (ED_node_is_compositor(snode)) {
+          /* note that nodeUpdateID is already called by BKE_image_signal() on all
+           * scenes so really this is just to know if the images is used in the compo else
+           * painting on images could become very slow when the compositor is open. */
+          if (nodeUpdateID(snode->nodetree, (ID *)wmn->reference)) {
+            ED_area_tag_refresh(area);
+          }
+        }
+      }
+      break;
+
+    case NC_MOVIECLIP:
+      if (wmn->action == NA_EDITED) {
+        if (ED_node_is_compositor(snode)) {
+          if (nodeUpdateID(snode->nodetree, (ID *)wmn->reference)) {
+            ED_area_tag_refresh(area);
+          }
+        }
+      }
+      break;
+
+    case NC_LINESTYLE:
+      if (ED_node_is_shader(snode) && shader_type == SNODE_SHADER_LINESTYLE) {
+        ED_area_tag_refresh(area);
+      }
+      break;
+    case NC_WM:
+      if (wmn->data == ND_UNDO) {
+        ED_area_tag_refresh(area);
+      }
+      break;
+    case NC_GPENCIL:
+      if (ELEM(wmn->action, NA_EDITED, NA_SELECTED)) {
+        ED_area_tag_redraw(area);
+      }
+      break;
+  }
+}
+
+static void node_area_refresh(const struct bContext *C, ScrArea *area)
+{
+  /* default now: refresh node is starting preview */
+  SpaceNode *snode = (SpaceNode *)area->spacedata.first;
+
+  snode_set_context(C);
+
+  if (snode->nodetree) {
+    if (snode->nodetree->type == NTREE_SHADER) {
+      if (GS(snode->id->name) == ID_MA) {
+        Material *ma = (Material *)snode->id;
+        if (ma->use_nodes) {
+          ED_preview_shader_job(C, area, snode->id, nullptr, nullptr, 100, 100, PR_NODE_RENDER);
+        }
+      }
+      else if (GS(snode->id->name) == ID_LA) {
+        Light *la = (Light *)snode->id;
+        if (la->use_nodes) {
+          ED_preview_shader_job(C, area, snode->id, nullptr, nullptr, 100, 100, PR_NODE_RENDER);
+        }
+      }
+      else if (GS(snode->id->name) == ID_WO) {
+        World *wo = (World *)snode->id;
+        if (wo->use_nodes) {
+          ED_preview_shader_job(C, area, snode->id, nullptr, nullptr, 100, 100, PR_NODE_RENDER);
+        }
+      }
+    }
+    else if (snode->nodetree->type == NTREE_COMPOSIT) {
+      Scene *scene = (Scene *)snode->id;
+      if (scene->use_nodes) {
+        /* recalc is set on 3d view changes for auto compo */
+        if (snode->runtime->recalc) {
+          snode->runtime->recalc = false;
+          node_render_changed_exec((struct bContext *)C, nullptr);
+        }
+        else {
+          ED_node_composite_job(C, snode->nodetree, scene);
+        }
+      }
+    }
+    else if (snode->nodetree->type == NTREE_TEXTURE) {
+      Tex *tex = (Tex *)snode->id;
+      if (tex->use_nodes) {
+        ED_preview_shader_job(C, area, snode->id, nullptr, nullptr, 100, 100, PR_NODE_RENDER);
+      }
+    }
+  }
+}
+
+static SpaceLink *node_duplicate(SpaceLink *sl)
+{
+  SpaceNode *snode = (SpaceNode *)sl;
+  SpaceNode *snoden = (SpaceNode *)MEM_dupallocN(snode);
+
+  BLI_duplicatelist(&snoden->treepath, &snode->treepath);
+
+  if (snode->runtime != nullptr) {
+    snoden->runtime = (SpaceNode_Runtime *)MEM_dupallocN(snode->runtime);
+    BLI_listbase_clear(&snoden->runtime->linkdrag);
+  }
+
+  /* NOTE: no need to set node tree user counts,
+   * the editor only keeps at least 1 (id_us_ensure_real),
+   * which is already done by the original SpaceNode.
+   */
+
+  return (SpaceLink *)snoden;
+}
+
+/* add handlers, stuff you only do once or on area/region changes */
+static void node_buttons_region_init(wmWindowManager *wm, ARegion *region)
+{
+  wmKeyMap *keymap;
+
+  ED_region_panels_init(wm, region);
+
+  keymap = WM_keymap_ensure(wm->defaultconf, "Node Generic", SPACE_NODE, 0);
+  WM_event_add_keymap_handler(&region->handlers, keymap);
+}
+
+static void node_buttons_region_draw(const bContext *C, ARegion *region)
+{
+  ED_region_panels(C, region);
+}
+
+/* add handlers, stuff you only do once or on area/region changes */
+static void node_toolbar_region_init(wmWindowManager *wm, ARegion *region)
+{
+  wmKeyMap *keymap;
+
+  ED_region_panels_init(wm, region);
+
+  keymap = WM_keymap_ensure(wm->defaultconf, "Node Generic", SPACE_NODE, 0);
+  WM_event_add_keymap_handler(&region->handlers, keymap);
+}
+
+static void node_toolbar_region_draw(const bContext *C, ARegion *region)
+{
+  ED_region_panels(C, region);
+}
+
+void ED_node_cursor_location_get(const SpaceNode *snode, float value[2])
+{
+  copy_v2_v2(value, snode->runtime->cursor);
+}
+
+void ED_node_cursor_location_set(SpaceNode *snode, const float value[2])
+{
+  copy_v2_v2(snode->runtime->cursor, value);
+}
+
+static void node_cursor(wmWindow *win, ScrArea *area, ARegion *region)
+{
+  SpaceNode *snode = (SpaceNode *)area->spacedata.first;
+
+  /* convert mouse coordinates to v2d space */
+  UI_view2d_region_to_view(&region->v2d,
+                           win->eventstate->xy[0] - region->winrct.xmin,
+                           win->eventstate->xy[1] - region->winrct.ymin,
+                           &snode->runtime->cursor[0],
+                           &snode->runtime->cursor[1]);
+
+  /* here snode->runtime->cursor is used to detect the node edge for sizing */
+  node_set_cursor(win, snode, snode->runtime->cursor);
+
+  /* XXX snode->runtime->cursor is in placing new nodes space */
+  snode->runtime->cursor[0] /= UI_DPI_FAC;
+  snode->runtime->cursor[1] /= UI_DPI_FAC;
+}
+
+/* Initialize main region, setting handlers. */
+static void node_main_region_init(wmWindowManager *wm, ARegion *region)
+{
+  wmKeyMap *keymap;
+  ListBase *lb;
+
+  UI_view2d_region_reinit(&region->v2d, V2D_COMMONVIEW_CUSTOM, region->winx, region->winy);
+
+  /* own keymaps */
+  keymap = WM_keymap_ensure(wm->defaultconf, "Node Generic", SPACE_NODE, 0);
+  WM_event_add_keymap_handler(&region->handlers, keymap);
+
+  keymap = WM_keymap_ensure(wm->defaultconf, "Node Editor", SPACE_NODE, 0);
+  WM_event_add_keymap_handler_v2d_mask(&region->handlers, keymap);
+
+  /* add drop boxes */
+  lb = WM_dropboxmap_find("Node Editor", SPACE_NODE, RGN_TYPE_WINDOW);
+
+  WM_event_add_dropbox_handler(&region->handlers, lb);
+
+  /* The backdrop image gizmo needs to change together with the view. So always refresh gizmos on
+   * region size changes. */
+  WM_gizmomap_tag_refresh(region->gizmo_map);
+}
+
+static void node_main_region_draw(const bContext *C, ARegion *region)
+{
+  node_draw_space(C, region);
+}
+
+/* ************* dropboxes ************* */
+
+static bool node_group_drop_poll(bContext *UNUSED(C), wmDrag *drag, const wmEvent *UNUSED(event))
+{
+  return WM_drag_is_ID_type(drag, ID_NT);
+}
+
+static bool node_object_drop_poll(bContext *UNUSED(C), wmDrag *drag, const wmEvent *UNUSED(event))
+{
+  return WM_drag_is_ID_type(drag, ID_OB);
+}
+
+static bool node_collection_drop_poll(bContext *UNUSED(C),
+                                      wmDrag *drag,
+                                      const wmEvent *UNUSED(event))
+{
+  return WM_drag_is_ID_type(drag, ID_GR);
+}
+
+static bool node_texture_drop_poll(bContext *UNUSED(C), wmDrag *drag, const wmEvent *UNUSED(event))
+{
+  return WM_drag_is_ID_type(drag, ID_TE);
+}
+
+static bool node_ima_drop_poll(bContext *UNUSED(C), wmDrag *drag, const wmEvent *UNUSED(event))
+{
+  if (drag->type == WM_DRAG_PATH) {
+    /* rule might not work? */
+    return (ELEM(drag->icon, 0, ICON_FILE_IMAGE, ICON_FILE_MOVIE));
+  }
+  return WM_drag_is_ID_type(drag, ID_IM);
+}
+
+static bool node_mask_drop_poll(bContext *UNUSED(C), wmDrag *drag, const wmEvent *UNUSED(event))
+{
+  return WM_drag_is_ID_type(drag, ID_MSK);
+}
+
+static void node_group_drop_copy(wmDrag *drag, wmDropBox *drop)
+{
+  ID *id = WM_drag_get_local_ID_or_import_from_asset(drag, 0);
+
+  RNA_string_set(drop->ptr, "name", id->name + 2);
+}
+
+static void node_id_drop_copy(wmDrag *drag, wmDropBox *drop)
+{
+  ID *id = WM_drag_get_local_ID_or_import_from_asset(drag, 0);
+
+  RNA_string_set(drop->ptr, "name", id->name + 2);
+}
+
+static void node_id_path_drop_copy(wmDrag *drag, wmDropBox *drop)
+{
+  ID *id = WM_drag_get_local_ID_or_import_from_asset(drag, 0);
+
+  if (id) {
+    RNA_string_set(drop->ptr, "name", id->name + 2);
+    RNA_struct_property_unset(drop->ptr, "filepath");
+  }
+  else if (drag->path[0]) {
+    RNA_string_set(drop->ptr, "filepath", drag->path);
+    RNA_struct_property_unset(drop->ptr, "name");
+  }
+}
+
+/* this region dropbox definition */
+static void node_dropboxes()
+{
+  ListBase *lb = WM_dropboxmap_find("Node Editor", SPACE_NODE, RGN_TYPE_WINDOW);
+
+  WM_dropbox_add(lb,
+                 "NODE_OT_add_object",
+                 node_object_drop_poll,
+                 node_id_drop_copy,
+                 WM_drag_free_imported_drag_ID,
+                 nullptr);
+  WM_dropbox_add(lb,
+                 "NODE_OT_add_collection",
+                 node_collection_drop_poll,
+                 node_id_drop_copy,
+                 WM_drag_free_imported_drag_ID,
+                 nullptr);
+  WM_dropbox_add(lb,
+                 "NODE_OT_add_texture",
+                 node_texture_drop_poll,
+                 node_id_drop_copy,
+                 WM_drag_free_imported_drag_ID,
+                 nullptr);
+  WM_dropbox_add(lb,
+                 "NODE_OT_add_group",
+                 node_group_drop_poll,
+                 node_group_drop_copy,
+                 WM_drag_free_imported_drag_ID,
+                 nullptr);
+  WM_dropbox_add(lb,
+                 "NODE_OT_add_file",
+                 node_ima_drop_poll,
+                 node_id_path_drop_copy,
+                 WM_drag_free_imported_drag_ID,
+                 nullptr);
+  WM_dropbox_add(lb,
+                 "NODE_OT_add_mask",
+                 node_mask_drop_poll,
+                 node_id_drop_copy,
+                 WM_drag_free_imported_drag_ID,
+                 nullptr);
+}
+
+/* ************* end drop *********** */
+
+/* add handlers, stuff you only do once or on area/region changes */
+static void node_header_region_init(wmWindowManager *UNUSED(wm), ARegion *region)
+{
+  ED_region_header_init(region);
+}
+
+static void node_header_region_draw(const bContext *C, ARegion *region)
+{
+  /* find and set the context */
+  snode_set_context(C);
+
+  ED_region_header(C, region);
+}
+
+/* used for header + main region */
+static void node_region_listener(const wmRegionListenerParams *params)
+{
+  ARegion *region = params->region;
+  wmNotifier *wmn = params->notifier;
+  wmGizmoMap *gzmap = region->gizmo_map;
+
+  /* context changes */
+  switch (wmn->category) {
+    case NC_SPACE:
+      switch (wmn->data) {
+        case ND_SPACE_NODE:
+          ED_region_tag_redraw(region);
+          break;
+        case ND_SPACE_NODE_VIEW:
+          WM_gizmomap_tag_refresh(gzmap);
+          break;
+      }
+      break;
+    case NC_SCREEN:
+      if (wmn->data == ND_LAYOUTSET || wmn->action == NA_EDITED) {
+        WM_gizmomap_tag_refresh(gzmap);
+      }
+      switch (wmn->data) {
+        case ND_ANIMPLAY:
+        case ND_LAYER:
+          ED_region_tag_redraw(region);
+          break;
+      }
+      break;
+    case NC_WM:
+      if (wmn->data == ND_JOB) {
+        ED_region_tag_redraw(region);
+      }
+      break;
+    case NC_SCENE:
+      ED_region_tag_redraw(region);
+      if (wmn->data == ND_RENDER_RESULT) {
+        WM_gizmomap_tag_refresh(gzmap);
+      }
+      break;
+    case NC_NODE:
+      ED_region_tag_redraw(region);
+      if (ELEM(wmn->action, NA_EDITED, NA_SELECTED)) {
+        WM_gizmomap_tag_refresh(gzmap);
+      }
+      break;
+    case NC_MATERIAL:
+    case NC_TEXTURE:
+    case NC_WORLD:
+    case NC_LINESTYLE:
+      ED_region_tag_redraw(region);
+      break;
+    case NC_OBJECT:
+      if (wmn->data == ND_OB_SHADING) {
+        ED_region_tag_redraw(region);
+      }
+      break;
+    case NC_ID:
+      if (wmn->action == NA_RENAME) {
+        ED_region_tag_redraw(region);
+      }
+      break;
+    case NC_GPENCIL:
+      if (wmn->action == NA_EDITED) {
+        ED_region_tag_redraw(region);
+      }
+      else if (wmn->data & ND_GPENCIL_EDITMODE) {
+        ED_region_tag_redraw(region);
+      }
+      break;
+  }
+}
+
+const char *node_context_dir[] = {
+    "selected_nodes", "active_node", "light", "material", "world", nullptr};
+static int /*eContextResult*/ node_context(const bContext *C,
+                                           const char *member,
+                                           bContextDataResult *result)
+{
+  SpaceNode *snode = CTX_wm_space_node(C);
+
+  if (CTX_data_dir(member)) {
+    CTX_data_dir_set(result, node_context_dir);
+    return CTX_RESULT_OK;
+  }
+  if (CTX_data_equals(member, "selected_nodes")) {
+    if (snode->edittree) {
+      LISTBASE_FOREACH_BACKWARD (bNode *, node, &snode->edittree->nodes) {
+        if (node->flag & NODE_SELECT) {
+          CTX_data_list_add(result, &snode->edittree->id, &RNA_Node, node);
+        }
+      }
+    }
+    CTX_data_type_set(result, CTX_DATA_TYPE_COLLECTION);
+    return CTX_RESULT_OK;
+  }
+  if (CTX_data_equals(member, "active_node")) {
+    if (snode->edittree) {
+      bNode *node = nodeGetActive(snode->edittree);
+      CTX_data_pointer_set(result, &snode->edittree->id, &RNA_Node, node);
+    }
+
+    CTX_data_type_set(result, CTX_DATA_TYPE_POINTER);
+    return CTX_RESULT_OK;
+  }
+  if (CTX_data_equals(member, "node_previews")) {
+    if (snode->nodetree) {
+      CTX_data_pointer_set(
+          result, &snode->nodetree->id, &RNA_NodeInstanceHash, snode->nodetree->previews);
+    }
+
+    CTX_data_type_set(result, CTX_DATA_TYPE_POINTER);
+    return CTX_RESULT_OK;
+  }
+  if (CTX_data_equals(member, "material")) {
+    if (snode->id && GS(snode->id->name) == ID_MA) {
+      CTX_data_id_pointer_set(result, snode->id);
+    }
+    return CTX_RESULT_OK;
+  }
+  if (CTX_data_equals(member, "light")) {
+    if (snode->id && GS(snode->id->name) == ID_LA) {
+      CTX_data_id_pointer_set(result, snode->id);
+    }
+    return CTX_RESULT_OK;
+  }
+  if (CTX_data_equals(member, "world")) {
+    if (snode->id && GS(snode->id->name) == ID_WO) {
+      CTX_data_id_pointer_set(result, snode->id);
+    }
+    return CTX_RESULT_OK;
+  }
+
+  return CTX_RESULT_MEMBER_NOT_FOUND;
+}
+
+static void node_widgets()
+{
+  /* create the widgetmap for the area here */
+  wmGizmoMapType_Params params{SPACE_NODE, RGN_TYPE_WINDOW};
+  wmGizmoMapType *gzmap_type = WM_gizmomaptype_ensure(&params);
+  WM_gizmogrouptype_append_and_link(gzmap_type, NODE_GGT_backdrop_transform);
+  WM_gizmogrouptype_append_and_link(gzmap_type, NODE_GGT_backdrop_crop);
+  WM_gizmogrouptype_append_and_link(gzmap_type, NODE_GGT_backdrop_sun_beams);
+  WM_gizmogrouptype_append_and_link(gzmap_type, NODE_GGT_backdrop_corner_pin);
+}
+
+static void node_id_remap(ScrArea *UNUSED(area), SpaceLink *slink, ID *old_id, ID *new_id)
+{
+  SpaceNode *snode = (SpaceNode *)slink;
+
+  if (snode->id == old_id) {
+    /* nasty DNA logic for SpaceNode:
+     * ideally should be handled by editor code, but would be bad level call
+     */
+    BLI_freelistN(&snode->treepath);
+
+    /* XXX Untested in case new_id != nullptr... */
+    snode->id = new_id;
+    snode->from = nullptr;
+    snode->nodetree = nullptr;
+    snode->edittree = nullptr;
+  }
+  else if (GS(old_id->name) == ID_OB) {
+    if (snode->from == old_id) {
+      if (new_id == nullptr) {
+        snode->flag &= ~SNODE_PIN;
+      }
+      snode->from = new_id;
+    }
+  }
+  else if (GS(old_id->name) == ID_GD) {
+    if ((ID *)snode->gpd == old_id) {
+      snode->gpd = (bGPdata *)new_id;
+      id_us_min(old_id);
+      id_us_plus(new_id);
+    }
+  }
+  else if (GS(old_id->name) == ID_NT) {
+    bNodeTreePath *path, *path_next;
+
+    for (path = (bNodeTreePath *)snode->treepath.first; path; path = path->next) {
+      if ((ID *)path->nodetree == old_id) {
+        path->nodetree = (bNodeTree *)new_id;
+        id_us_ensure_real(new_id);
+      }
+      if (path == snode->treepath.first) {
+        /* first nodetree in path is same as snode->nodetree */
+        snode->nodetree = path->nodetree;
+      }
+      if (path->nodetree == nullptr) {
+        break;
+      }
+    }
+
+    /* remaining path entries are invalid, remove */
+    for (; path; path = path_next) {
+      path_next = path->next;
+
+      BLI_remlink(&snode->treepath, path);
+      MEM_freeN(path);
+    }
+
+    /* edittree is just the last in the path,
+     * set this directly since the path may have been shortened above */
+    if (snode->treepath.last) {
+      path = (bNodeTreePath *)snode->treepath.last;
+      snode->edittree = path->nodetree;
+    }
+    else {
+      snode->edittree = nullptr;
+    }
+  }
+}
+
+static int node_space_subtype_get(ScrArea *area)
+{
+  SpaceNode *snode = (SpaceNode *)area->spacedata.first;
+  return rna_node_tree_idname_to_enum(snode->tree_idname);
+}
+
+static void node_space_subtype_set(ScrArea *area, int value)
+{
+  SpaceNode *snode = (SpaceNode *)area->spacedata.first;
+  ED_node_set_tree_type(snode, rna_node_tree_type_from_enum(value));
+}
+
+static void node_space_subtype_item_extend(bContext *C, EnumPropertyItem **item, int *totitem)
+{
+  bool free;
+  const EnumPropertyItem *item_src = RNA_enum_node_tree_types_itemf_impl(C, &free);
+  RNA_enum_items_add(item, totitem, item_src);
+  if (free) {
+    MEM_freeN((void *)item_src);
+  }
+}
+
+/* only called once, from space/spacetypes.c */
+void ED_spacetype_node(void)
+{
+  SpaceType *st = (SpaceType *)MEM_callocN(sizeof(SpaceType), "spacetype node");
+  ARegionType *art;
+
+  st->spaceid = SPACE_NODE;
+  strncpy(st->name, "Node", BKE_ST_MAXNAME);
+
+  st->create = node_create;
+  st->free = node_free;
+  st->init = node_init;
+  st->duplicate = node_duplicate;
+  st->operatortypes = node_operatortypes;
+  st->keymap = node_keymap;
+  st->listener = node_area_listener;
+  st->refresh = node_area_refresh;
+  st->context = node_context;
+  st->dropboxes = node_dropboxes;
+  st->gizmos = node_widgets;
+  st->id_remap = node_id_remap;
+  st->space_subtype_item_extend = node_space_subtype_item_extend;
+  st->space_subtype_get = node_space_subtype_get;
+  st->space_subtype_set = node_space_subtype_set;
+
+  /* regions: main window */
+  art = (ARegionType *)MEM_callocN(sizeof(ARegionType), "spacetype node region");
+  art->regionid = RGN_TYPE_WINDOW;
+  art->init = node_main_region_init;
+  art->draw = node_main_region_draw;
+  art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_GIZMO | ED_KEYMAP_TOOL | ED_KEYMAP_VIEW2D |
+                    ED_KEYMAP_FRAMES | ED_KEYMAP_GPENCIL;
+  art->listener = node_region_listener;
+  art->cursor = node_cursor;
+  art->event_cursor = true;
+  art->clip_gizmo_events_by_ui = true;
+
+  BLI_addhead(&st->regiontypes, art);
+
+  /* regions: header */
+  art = (ARegionType *)MEM_callocN(sizeof(ARegionType), "spacetype node region");
+  art->regionid = RGN_TYPE_HEADER;
+  art->prefsizey = HEADERY;
+  art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_VIEW2D | ED_KEYMAP_FRAMES | ED_KEYMAP_HEADER;
+  art->listener = node_region_listener;
+  art->init = node_header_region_init;
+  art->draw = node_header_region_draw;
+
+  BLI_addhead(&st->regiontypes, art);
+
+  /* regions: listview/buttons */
+  art = (ARegionType *)MEM_callocN(sizeof(ARegionType), "spacetype node region");
+  art->regionid = RGN_TYPE_UI;
+  art->prefsizex = UI_SIDEBAR_PANEL_WIDTH;
+  art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_FRAMES;
+  art->listener = node_region_listener;
+  art->message_subscribe = ED_area_do_mgs_subscribe_for_tool_ui;
+  art->init = node_buttons_region_init;
+  art->draw = node_buttons_region_draw;
+  BLI_addhead(&st->regiontypes, art);
+
+  /* regions: toolbar */
+  art = (ARegionType *)MEM_callocN(sizeof(ARegionType), "spacetype view3d tools region");
+  art->regionid = RGN_TYPE_TOOLS;
+  art->prefsizex = 58; /* XXX */
+  art->prefsizey = 50; /* XXX */
+  art->keymapflag = ED_KEYMAP_UI | ED_KEYMAP_FRAMES;
+  art->listener = node_region_listener;
+  art->message_subscribe = ED_region_generic_tools_region_message_subscribe;
+  art->snap_size = ED_region_generic_tools_region_snap_size;
+  art->init = node_toolbar_region_init;
+  art->draw = node_toolbar_region_draw;
+  BLI_addhead(&st->regiontypes, art);
+
+  node_toolbar_register(art);
+
+  BKE_spacetype_register(st);
+}