space_node.cc

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/* SPDX-FileCopyrightText: 2008 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#include "AS_asset_representation.hh"
 
#include "BLI_listbase.h"
#include "BLI_math_vector.h"
#include "BLI_stack.hh"
#include "BLI_string.h"
 
#include "DNA_ID.h"
#include "DNA_gpencil_legacy_types.h"
#include "DNA_material_types.h"
#include "DNA_modifier_types.h"
#include "DNA_node_types.h"
#include "DNA_object_types.h"
#include "DNA_screen_types.h"
#include "DNA_space_types.h"
#include "DNA_windowmanager_types.h"
 
#include "MEM_guardedalloc.h"
 
#include "BKE_asset.hh"
#include "BKE_compute_context_cache.hh"
#include "BKE_compute_contexts.hh"
#include "BKE_context.hh"
#include "BKE_gpencil_legacy.h"
#include "BKE_idprop.hh"
#include "BKE_lib_id.hh"
#include "BKE_lib_query.hh"
#include "BKE_lib_remap.hh"
#include "BKE_node_legacy_types.hh"
#include "BKE_node_runtime.hh"
#include "BKE_node_tree_zones.hh"
#include "BKE_screen.hh"
 
#include "BLT_translation.hh"
 
#include "ED_image.hh"
#include "ED_node.hh"
#include "ED_node_preview.hh"
#include "ED_screen.hh"
#include "ED_space_api.hh"
 
#include "UI_view2d.hh"
 
#include "DEG_depsgraph.hh"
#include "DEG_depsgraph_query.hh"
 
#include "BLO_read_write.hh"
 
#include "RNA_access.hh"
#include "RNA_define.hh"
#include "RNA_enum_types.hh"
#include "RNA_prototypes.hh"
 
#include "WM_api.hh"
#include "WM_types.hh"
 
#include "NOD_node_in_compute_context.hh"
#include "NOD_socket_interface_key.hh"
 
#include "io_utils.hh"
 
#include "node_intern.hh" /* own include */
 
using blender::float2;
 
/* ******************** tree path ********************* */
 
void ED_node_tree_start(ARegion *region, 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 = MEM_callocN<bNodeTreePath>("node tree path");
    path->nodetree = ntree;
    path->parent_key = blender::bke::NODE_INSTANCE_KEY_BASE;
 
    /* Set initial view center from node tree. */
    copy_v2_v2(path->view_center, ntree->view_center);
    if (region) {
      UI_view2d_center_set(&region->v2d, ntree->view_center[0], ntree->view_center[1]);
    }
 
    if (id) {
      STRNCPY(path->display_name, id->name + 2);
    }
 
    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 #36024. 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(ARegion *region, SpaceNode *snode, bNodeTree *ntree, bNode *gnode)
{
  bNodeTreePath *path = MEM_callocN<bNodeTreePath>("node tree path");
  bNodeTreePath *prev_path = (bNodeTreePath *)snode->treepath.last;
  path->nodetree = ntree;
  if (gnode) {
    if (prev_path) {
      path->parent_key = blender::bke::node_instance_key(
          prev_path->parent_key, prev_path->nodetree, gnode);
    }
    else {
      path->parent_key = blender::bke::NODE_INSTANCE_KEY_BASE;
    }
 
    STRNCPY(path->node_name, gnode->name);
    STRNCPY(path->display_name, gnode->name);
  }
  else {
    path->parent_key = blender::bke::NODE_INSTANCE_KEY_BASE;
  }
 
  /* Set initial view center from node tree. */
  copy_v2_v2(path->view_center, ntree->view_center);
  if (region) {
    UI_view2d_center_set(&region->v2d, ntree->view_center[0], ntree->view_center[1]);
  }
 
  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(ARegion *region, 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;
 
  /* Set view center from node tree path. */
  if (region) {
    UI_view2d_center_set(&region->v2d, path->view_center[0], path->view_center[1]);
  }
 
  ED_node_set_active_viewer_key(snode);
 
  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;
#ifndef NDEBUG
  const char *value_orig = value;
#endif
  /* Note that the caller ensures there is enough space available. */
  LISTBASE_FOREACH_INDEX (bNodeTreePath *, path, &snode->treepath, i) {
    const int len = strlen(path->display_name);
    if (i != 0) {
      *value++ = '/';
    }
    memcpy(value, path->display_name, len);
    value += len;
  }
  *value = '\0';
  BLI_assert(ptrdiff_t(ED_node_tree_path_length(snode)) == ptrdiff_t(value - value_orig));
}
 
void ED_node_set_active_viewer_key(SpaceNode *snode)
{
  bNodeTreePath *path = (bNodeTreePath *)snode->treepath.last;
  if (snode->nodetree && path) {
    /* A change in active viewer may result in the change of the output node used by the
     * compositor, so we need to get notified about such changes. */
    if (snode->nodetree->active_viewer_key.value != path->parent_key.value &&
        snode->nodetree->type == NTREE_COMPOSIT)
    {
      DEG_id_tag_update(&snode->nodetree->id, ID_RECALC_NTREE_OUTPUT);
      WM_main_add_notifier(NC_NODE, nullptr);
    }
 
    snode->nodetree->active_viewer_key = path->parent_key;
  }
}
 
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);
}
 
namespace blender::ed::space_node {
 
float2 space_node_group_offset(const SpaceNode &snode)
{
  const bNodeTreePath *path = (bNodeTreePath *)snode.treepath.last;
 
  if (path && path->prev) {
    return float2(path->view_center) - float2(path->prev->view_center);
  }
  return float2(0);
}
 
std::optional<nodes::FoundNestedNodeID> find_nested_node_id_in_root(const SpaceNode &snode,
                                                                    const bNode &query_node)
{
  BLI_assert(snode.edittree->runtime->nodes_by_id.contains(const_cast<bNode *>(&query_node)));
  bke::ComputeContextCache compute_context_cache;
  const ComputeContext *compute_context = compute_context_for_edittree_node(
      snode, compute_context_cache, query_node);
  if (!compute_context) {
    return {};
  }
  return find_nested_node_id_in_root(*snode.nodetree, compute_context, query_node.identifier);
}
 
std::optional<nodes::FoundNestedNodeID> find_nested_node_id_in_root(
    const bNodeTree &root_tree, const ComputeContext *compute_context, const int node_id)
{
  nodes::FoundNestedNodeID found;
  Vector<int> node_ids;
  for (const ComputeContext *context = compute_context; context != nullptr;
       context = context->parent())
  {
    if (const auto *node_context = dynamic_cast<const bke::GroupNodeComputeContext *>(context)) {
      node_ids.append(node_context->node_id());
    }
    else if (dynamic_cast<const bke::RepeatZoneComputeContext *>(context) != nullptr) {
      found.is_in_loop = true;
    }
    else if (dynamic_cast<const bke::SimulationZoneComputeContext *>(context) != nullptr) {
      found.is_in_simulation = true;
    }
    else if (dynamic_cast<const bke::ForeachGeometryElementZoneComputeContext *>(context) !=
             nullptr)
    {
      found.is_in_loop = true;
    }
    else if (dynamic_cast<const bke::EvaluateClosureComputeContext *>(context) != nullptr) {
      found.is_in_closure = true;
    }
  }
  std::reverse(node_ids.begin(), node_ids.end());
  node_ids.append(node_id);
  const bNestedNodeRef *nested_node_ref = root_tree.nested_node_ref_from_node_id_path(node_ids);
  if (nested_node_ref == nullptr) {
    return std::nullopt;
  }
  found.id = nested_node_ref->id;
  return found;
}
 
std::optional<ObjectAndModifier> get_modifier_for_node_editor(const SpaceNode &snode)
{
  if (snode.geometry_nodes_type != SNODE_GEOMETRY_MODIFIER) {
    return std::nullopt;
  }
  if (snode.id == nullptr) {
    return std::nullopt;
  }
  if (GS(snode.id->name) != ID_OB) {
    return std::nullopt;
  }
  const Object *object = reinterpret_cast<Object *>(snode.id);
  const NodesModifierData *used_modifier = nullptr;
  if (snode.flag & SNODE_PIN) {
    LISTBASE_FOREACH (const ModifierData *, md, &object->modifiers) {
      if (md->type == eModifierType_Nodes) {
        const NodesModifierData *nmd = reinterpret_cast<const NodesModifierData *>(md);
        /* Would be good to store the name of the pinned modifier in the node editor. */
        if (nmd->node_group == snode.nodetree) {
          used_modifier = nmd;
          break;
        }
      }
    }
  }
  else {
    LISTBASE_FOREACH (const ModifierData *, md, &object->modifiers) {
      if (md->type == eModifierType_Nodes) {
        const NodesModifierData *nmd = reinterpret_cast<const NodesModifierData *>(md);
        if (nmd->node_group == snode.nodetree) {
          if (md->flag & eModifierFlag_Active) {
            used_modifier = nmd;
            break;
          }
        }
      }
    }
  }
  if (used_modifier == nullptr) {
    return std::nullopt;
  }
  return ObjectAndModifier{object, used_modifier};
}
 
bool node_editor_is_for_geometry_nodes_modifier(const SpaceNode &snode,
                                                const Object &object,
                                                const NodesModifierData &nmd)
{
  const std::optional<ObjectAndModifier> object_and_modifier = get_modifier_for_node_editor(snode);
  if (!object_and_modifier) {
    return false;
  }
  const Object *object_orig = DEG_is_original(&object) ? &object : DEG_get_original(&object);
  if (object_and_modifier->object != object_orig) {
    return false;
  }
  return object_and_modifier->nmd->modifier.persistent_uid == nmd.modifier.persistent_uid;
}
 
const ComputeContext *compute_context_for_zone(const bke::bNodeTreeZone &zone,
                                               bke::ComputeContextCache &compute_context_cache,
                                               const ComputeContext *parent_compute_context)
{
  const bNode *output_node_ptr = zone.output_node();
  if (!output_node_ptr) {
    return nullptr;
  }
  const bNode &output_node = *output_node_ptr;
  switch (output_node.type_legacy) {
    case GEO_NODE_SIMULATION_OUTPUT: {
      return &compute_context_cache.for_simulation_zone(parent_compute_context, output_node);
    }
    case GEO_NODE_REPEAT_OUTPUT: {
      const auto &storage = *static_cast<const NodeGeometryRepeatOutput *>(output_node.storage);
      return &compute_context_cache.for_repeat_zone(
          parent_compute_context, output_node, storage.inspection_index);
    }
    case GEO_NODE_FOREACH_GEOMETRY_ELEMENT_OUTPUT: {
      const auto &storage = *static_cast<const NodeGeometryForeachGeometryElementOutput *>(
          output_node.storage);
      return &compute_context_cache.for_foreach_geometry_element_zone(
          parent_compute_context, output_node, storage.inspection_index);
    }
    case GEO_NODE_CLOSURE_OUTPUT: {
      nodes::ClosureSourceLocation source_location{};
      const bNodeTree &tree = output_node.owner_tree();
      source_location.tree = &tree;
      source_location.closure_output_node_id = output_node.identifier;
      source_location.compute_context_hash = parent_compute_context ?
                                                 parent_compute_context->hash() :
                                                 ComputeContextHash{};
      return compute_context_for_closure_evaluation(parent_compute_context,
                                                    output_node.output_socket(0),
                                                    compute_context_cache,
                                                    source_location);
    }
  }
  return nullptr;
}
 
static const ComputeContext *compute_context_for_zones(
    const Span<const bke::bNodeTreeZone *> zones,
    bke::ComputeContextCache &compute_context_cache,
    const ComputeContext *parent_compute_context)
{
  const ComputeContext *current = parent_compute_context;
  for (const bke::bNodeTreeZone *zone : zones) {
    current = compute_context_for_zone(*zone, compute_context_cache, current);
    if (!current) {
      return nullptr;
    }
  }
  return current;
}
 
static std::optional<const ComputeContext *> compute_context_for_tree_path(
    const SpaceNode &snode,
    bke::ComputeContextCache &compute_context_cache,
    const ComputeContext *parent_compute_context)
{
  const ComputeContext *current = parent_compute_context;
  Vector<const bNodeTreePath *> tree_path;
  LISTBASE_FOREACH (const bNodeTreePath *, item, &snode.treepath) {
    tree_path.append(item);
  }
  if (tree_path.is_empty()) {
    return current;
  }
 
  for (const int i : tree_path.index_range().drop_back(1)) {
    bNodeTree *tree = tree_path[i]->nodetree;
    const char *group_node_name = tree_path[i + 1]->node_name;
    const bNode *group_node = blender::bke::node_find_node_by_name(*tree, group_node_name);
    if (group_node == nullptr) {
      return std::nullopt;
    }
    const blender::bke::bNodeTreeZones *tree_zones = tree->zones();
    if (tree_zones == nullptr) {
      return std::nullopt;
    }
    const Vector<const blender::bke::bNodeTreeZone *> zone_stack =
        tree_zones->get_zones_to_enter_from_root(
            tree_zones->get_zone_by_node(group_node->identifier));
    current = compute_context_for_zones(zone_stack, compute_context_cache, current);
    if (!current) {
      return std::nullopt;
    }
    current = &compute_context_cache.for_group_node(current, group_node->identifier, tree);
  }
  return current;
}
 
[[nodiscard]] const ComputeContext *compute_context_for_closure_evaluation(
    const ComputeContext *closure_socket_context,
    const bNodeSocket &closure_socket,
    bke::ComputeContextCache &compute_context_cache,
    const std::optional<nodes::ClosureSourceLocation> &source_location)
{
  using BundlePath = Vector<nodes::SocketInterfaceKey, 0>;
 
  struct SocketToCheck {
    nodes::SocketInContext socket;
    BundlePath bundle_path;
  };
 
  Stack<SocketToCheck> sockets_to_check;
  Set<nodes::SocketInContext> added_sockets;
 
  auto add_if_new = [&](const nodes::SocketInContext &socket, BundlePath bundle_path) {
    if (added_sockets.add(socket)) {
      sockets_to_check.push({socket, std::move(bundle_path)});
    }
  };
 
  const nodes::SocketInContext start_socket{closure_socket_context, &closure_socket};
  add_if_new(start_socket, {});
 
  while (!sockets_to_check.is_empty()) {
    const SocketToCheck socket_to_check = sockets_to_check.pop();
    const nodes::SocketInContext socket = socket_to_check.socket;
    const BundlePath &bundle_path = socket_to_check.bundle_path;
    const nodes::NodeInContext &node = socket.owner_node();
    if (socket->is_input()) {
      if (node->is_muted()) {
        for (const bNodeLink &link : node->internal_links()) {
          if (link.fromsock == socket.socket) {
            add_if_new({socket.context, link.tosock}, bundle_path);
          }
        }
        continue;
      }
      if (node->is_type("GeometryNodeEvaluateClosure")) {
        return &compute_context_cache.for_evaluate_closure(
            socket.context, node->identifier, &node->owner_tree(), source_location);
      }
      if (node->is_group()) {
        if (const bNodeTree *group = reinterpret_cast<const bNodeTree *>(node->id)) {
          group->ensure_topology_cache();
          const ComputeContext &group_compute_context = compute_context_cache.for_group_node(
              socket.context, node->identifier, &node->owner_tree());
          for (const bNode *input_node : group->group_input_nodes()) {
            const bNodeSocket &group_input_socket = input_node->output_socket(socket->index());
            if (group_input_socket.is_directly_linked()) {
              add_if_new({&group_compute_context, &group_input_socket}, bundle_path);
            }
          }
        }
        continue;
      }
      if (node->is_group_output()) {
        if (const auto *group_context = dynamic_cast<const bke::GroupNodeComputeContext *>(
                socket.context))
        {
          const bNodeTree *caller_group = group_context->tree();
          const bNode *caller_group_node = group_context->node();
          if (caller_group && caller_group_node) {
            caller_group->ensure_topology_cache();
            const bNodeSocket &output_socket = caller_group_node->output_socket(socket->index());
            add_if_new({group_context->parent(), &output_socket}, bundle_path);
          }
        }
        continue;
      }
      if (node->is_type("GeometryNodeCombineBundle")) {
        const auto &storage = *static_cast<const NodeGeometryCombineBundle *>(node->storage);
        BundlePath new_bundle_path = bundle_path;
        new_bundle_path.append(nodes::SocketInterfaceKey{storage.items[socket->index()].name});
        add_if_new(node.output_socket(0), std::move(new_bundle_path));
        continue;
      }
      if (node->is_type("GeometryNodeSeparateBundle")) {
        if (bundle_path.is_empty()) {
          continue;
        }
        const nodes::SocketInterfaceKey &last_key = bundle_path.last();
        const auto &storage = *static_cast<const NodeGeometrySeparateBundle *>(node->storage);
        for (const int output_i : IndexRange(storage.items_num)) {
          const nodes::SocketInterfaceKey key{storage.items[output_i].name};
          if (last_key.matches(key)) {
            add_if_new(node.output_socket(output_i), bundle_path.as_span().drop_back(1));
          }
        }
        continue;
      }
    }
    else {
      const bke::bNodeTreeZones *zones = node->owner_tree().zones();
      if (!zones) {
        continue;
      }
      const bke::bNodeTreeZone *from_zone = zones->get_zone_by_socket(*socket.socket);
      for (const bNodeLink *link : socket->directly_linked_links()) {
        if (!link->is_used()) {
          continue;
        }
        bNodeSocket *to_socket = link->tosock;
        const bke::bNodeTreeZone *to_zone = zones->get_zone_by_socket(*to_socket);
        if (!zones->link_between_zones_is_allowed(from_zone, to_zone)) {
          continue;
        }
        const Vector<const bke::bNodeTreeZone *> zones_to_enter = zones->get_zones_to_enter(
            from_zone, to_zone);
        const ComputeContext *compute_context = compute_context_for_zones(
            zones_to_enter, compute_context_cache, socket.context);
        if (!compute_context) {
          continue;
        }
        add_if_new({compute_context, to_socket}, bundle_path);
      }
    }
  }
  return nullptr;
}
 
static const ComputeContext *get_node_editor_root_compute_context(
    const SpaceNode &snode, bke::ComputeContextCache &compute_context_cache)
{
  switch (SpaceNodeGeometryNodesType(snode.geometry_nodes_type)) {
    case SNODE_GEOMETRY_MODIFIER: {
      std::optional<ed::space_node::ObjectAndModifier> object_and_modifier =
          ed::space_node::get_modifier_for_node_editor(snode);
      if (!object_and_modifier) {
        return nullptr;
      }
      return &compute_context_cache.for_modifier(nullptr, *object_and_modifier->nmd);
    }
    case SNODE_GEOMETRY_TOOL: {
      return &compute_context_cache.for_operator(nullptr);
    }
  }
  return nullptr;
}
 
[[nodiscard]] const ComputeContext *compute_context_for_edittree(
    const SpaceNode &snode, bke::ComputeContextCache &compute_context_cache)
{
  if (!snode.edittree) {
    return nullptr;
  }
  if (snode.edittree->type != NTREE_GEOMETRY) {
    return nullptr;
  }
  const ComputeContext *root_context = get_node_editor_root_compute_context(snode,
                                                                            compute_context_cache);
  if (!root_context) {
    return nullptr;
  }
  const ComputeContext *edittree_context =
      compute_context_for_tree_path(snode, compute_context_cache, root_context).value_or(nullptr);
  return edittree_context;
}
 
const ComputeContext *compute_context_for_edittree_socket(
    const SpaceNode &snode,
    bke::ComputeContextCache &compute_context_cache,
    const bNodeSocket &socket)
{
  const ComputeContext *context = compute_context_for_edittree(snode, compute_context_cache);
  if (!context) {
    return nullptr;
  }
  const bke::bNodeTreeZones *zones = snode.edittree->zones();
  if (!zones) {
    return nullptr;
  }
  const bke::bNodeTreeZone *zone = zones->get_zone_by_socket(socket);
  const Vector<const bke::bNodeTreeZone *> zone_stack = zones->get_zones_to_enter_from_root(zone);
  return compute_context_for_zones(zone_stack, compute_context_cache, context);
}
 
const ComputeContext *compute_context_for_edittree_node(
    const SpaceNode &snode, bke::ComputeContextCache &compute_context_cache, const bNode &node)
{
  const ComputeContext *context = compute_context_for_edittree(snode, compute_context_cache);
  if (!context) {
    return nullptr;
  }
  const bke::bNodeTreeZones *zones = snode.edittree->zones();
  if (!zones) {
    return nullptr;
  }
  const bke::bNodeTreeZone *zone = zones->get_zone_by_node(node.identifier);
  const Vector<const bke::bNodeTreeZone *> zone_stack = zones->get_zones_to_enter_from_root(zone);
  return compute_context_for_zones(zone_stack, compute_context_cache, context);
}
 
/* ******************** default callbacks for node space ***************** */
 
static SpaceLink *node_create(const ScrArea * /*area*/, const Scene * /*scene*/)
{
  SpaceNode *snode = MEM_callocN<SpaceNode>(__func__);
  snode->spacetype = SPACE_NODE;
 
  snode->flag = SNODE_SHOW_GPENCIL | SNODE_USE_ALPHA;
  snode->overlay.flag = (SN_OVERLAY_SHOW_OVERLAYS | SN_OVERLAY_SHOW_WIRE_COLORS |
                         SN_OVERLAY_SHOW_PATH | SN_OVERLAY_SHOW_PREVIEWS);
 
  /* backdrop */
  snode->zoom = 1.0f;
 
  /* select the first tree type for valid type */
  for (const bke::bNodeTreeType *treetype : bke::node_tree_types_get()) {
    STRNCPY(snode->tree_idname, treetype->idname.c_str());
    break;
  }
 
  /* header */
  ARegion *region = BKE_area_region_new();
 
  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 = BKE_area_region_new();
 
  BLI_addtail(&snode->regionbase, region);
  region->regiontype = RGN_TYPE_UI;
  region->alignment = RGN_ALIGN_RIGHT;
 
  /* toolbar */
  region = BKE_area_region_new();
 
  BLI_addtail(&snode->regionbase, region);
  region->regiontype = RGN_TYPE_TOOLS;
  region->alignment = RGN_ALIGN_LEFT;
 
  region->flag = RGN_FLAG_HIDDEN;
 
  /* main region */
  region = BKE_area_region_new();
 
  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 = 0.05f;
  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;
  BLI_freelistN(&snode->treepath);
  MEM_delete(snode->runtime);
}
 
/* spacetype; init callback */
static void node_init(wmWindowManager * /*wm*/, ScrArea *area)
{
  SpaceNode *snode = static_cast<SpaceNode *>(area->spacedata.first);
 
  if (snode->runtime == nullptr) {
    snode->runtime = MEM_new<SpaceNode_Runtime>(__func__);
  }
}
 
static void node_exit(wmWindowManager *wm, ScrArea *area)
{
  SpaceNode *snode = static_cast<SpaceNode *>(area->spacedata.first);
 
  if (snode->runtime) {
    free_previews(*wm, *snode);
  }
}
 
static bool any_node_uses_id(const bNodeTree *ntree, const ID *id)
{
  if (ELEM(nullptr, ntree, id)) {
    return false;
  }
  for (const bNode *node : ntree->all_nodes()) {
    if (node->id == id) {
      return true;
    }
  }
  return false;
}

static void node_area_tag_tree_recalc(SpaceNode *snode, ScrArea *area)
{
  if (ED_node_is_compositor(snode)) {
    snode->runtime->recalc_regular_compositing = true;
  }
 
  ED_area_tag_refresh(area);
}
 
static void node_area_listener(const wmSpaceTypeListenerParams *params)
{
  ScrArea *area = params->area;
  const wmNotifier *wmn = params->notifier;
 
  /* NOTE: #ED_area_tag_refresh will re-execute compositor. */
  SpaceNode *snode = static_cast<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: {
          node_area_tag_tree_recalc(snode, area);
          break;
        }
        case ND_FRAME:
          node_area_tag_tree_recalc(snode, area);
          break;
        case ND_COMPO_RESULT: {
          ED_area_tag_redraw(area);
          /* Backdrop image offset is calculated during compositing so gizmos need to be updated
           * afterwards. */
          const ARegion *region = BKE_area_find_region_type(area, RGN_TYPE_WINDOW);
          WM_gizmomap_tag_refresh(region->runtime->gizmo_map);
          break;
        }
      }
      break;
 
    /* future: add ID checks? */
    case NC_MATERIAL:
      if (ED_node_is_shader(snode)) {
        if (wmn->data == ND_SHADING) {
          node_area_tag_tree_recalc(snode, area);
        }
        else if (wmn->data == ND_SHADING_DRAW) {
          node_area_tag_tree_recalc(snode, area);
        }
        else if (wmn->data == ND_SHADING_LINKS) {
          node_area_tag_tree_recalc(snode, area);
        }
      }
      break;
    case NC_TEXTURE:
      if (ED_node_is_shader(snode) || ED_node_is_texture(snode)) {
        if (wmn->data == ND_NODES) {
          node_area_tag_tree_recalc(snode, area);
        }
      }
      break;
    case NC_WORLD:
      if (ED_node_is_shader(snode) && shader_type == SNODE_SHADER_WORLD) {
        node_area_tag_tree_recalc(snode, area);
      }
      break;
    case NC_OBJECT:
      if (ED_node_is_shader(snode)) {
        if (wmn->data == ND_OB_SHADING) {
          node_area_tag_tree_recalc(snode, 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) {
            node_area_tag_tree_recalc(snode, area);
          }
        }
      }
      break;
    case NC_SPACE:
      if (wmn->data == ND_SPACE_NODE) {
        node_area_tag_tree_recalc(snode, area);
      }
      else if (wmn->data == ND_SPACE_NODE_VIEW) {
        ED_area_tag_redraw(area);
      }
      break;
    case NC_NODE:
      if (wmn->action == NA_EDITED) {
        if (ELEM(wmn->reference, snode->nodetree, snode->id, nullptr) || snode->id == nullptr) {
          node_area_tag_tree_recalc(snode, area);
        }
      }
      else if (wmn->action == NA_SELECTED) {
        ED_area_tag_redraw(area);
      }
      break;
    case NC_SCREEN:
      switch (wmn->data) {
        case ND_ANIMPLAY:
          node_area_tag_tree_recalc(snode, area);
          break;
      }
      break;
    case NC_MASK:
      if (wmn->action == NA_EDITED) {
        if (snode->nodetree && snode->nodetree->type == NTREE_COMPOSIT) {
          node_area_tag_tree_recalc(snode, area);
        }
      }
      break;
 
    case NC_IMAGE:
      if (wmn->action == NA_EDITED) {
        if (ED_node_is_compositor(snode)) {
          /* Without this check drawing on an image could become very slow when the compositor is
           * open. */
          if (any_node_uses_id(snode->nodetree, (ID *)wmn->reference)) {
            node_area_tag_tree_recalc(snode, area);
          }
        }
      }
      break;
 
    case NC_MOVIECLIP:
      if (wmn->action == NA_EDITED) {
        if (ED_node_is_compositor(snode)) {
          if (any_node_uses_id(snode->nodetree, (ID *)wmn->reference)) {
            node_area_tag_tree_recalc(snode, area);
          }
        }
      }
      break;
 
    case NC_LINESTYLE:
      if (ED_node_is_shader(snode) && shader_type == SNODE_SHADER_LINESTYLE) {
        node_area_tag_tree_recalc(snode, area);
      }
      break;
    case NC_WM:
      if (wmn->data == ND_UNDO) {
        node_area_tag_tree_recalc(snode, 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 bContext *C, ScrArea *area)
{
  /* default now: refresh node is starting preview */
  SpaceNode *snode = static_cast<SpaceNode *>(area->spacedata.first);
 
  snode_set_context(*C);
 
  if (snode->nodetree) {
    if (snode->nodetree->type == NTREE_COMPOSIT) {
      Scene *scene = (Scene *)snode->id;
      if (scene->use_nodes) {
        if (snode->runtime->recalc_regular_compositing) {
          snode->runtime->recalc_regular_compositing = false;
          ED_node_composite_job(C, snode->nodetree, scene);
        }
      }
    }
  }
}
 
static SpaceLink *node_duplicate(SpaceLink *sl)
{
  SpaceNode *snode = (SpaceNode *)sl;
  SpaceNode *snoden = (SpaceNode *)MEM_dupallocN(snode);
 
  BLI_duplicatelist(&snoden->treepath, &snode->treepath);
 
  snoden->runtime = MEM_new<SpaceNode_Runtime>(__func__);
 
  /* 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, RGN_TYPE_WINDOW);
  WM_event_add_keymap_handler(&region->runtime->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, RGN_TYPE_WINDOW);
  WM_event_add_keymap_handler(&region->runtime->handlers, keymap);
}
 
static void node_toolbar_region_draw(const bContext *C, ARegion *region)
{
  ED_region_panels(C, region);
}
 
static void node_cursor(wmWindow *win, ScrArea *area, ARegion *region)
{
  SpaceNode *snode = static_cast<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, *region, *snode, snode->runtime->cursor);
 
  /* XXX snode->runtime->cursor is in placing new nodes space */
  snode->runtime->cursor[0] /= UI_SCALE_FAC;
  snode->runtime->cursor[1] /= UI_SCALE_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, RGN_TYPE_WINDOW);
  WM_event_add_keymap_handler(&region->runtime->handlers, keymap);
 
  keymap = WM_keymap_ensure(wm->defaultconf, "Node Editor", SPACE_NODE, RGN_TYPE_WINDOW);
  WM_event_add_keymap_handler_v2d_mask(&region->runtime->handlers, keymap);
 
  /* add drop boxes */
  lb = WM_dropboxmap_find("Node Editor", SPACE_NODE, RGN_TYPE_WINDOW);
 
  WM_event_add_dropbox_handler(&region->runtime->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->runtime->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 *C, wmDrag *drag, const wmEvent * /*event*/)
{
  SpaceNode *snode = CTX_wm_space_node(C);
 
  if (snode == nullptr) {
    return false;
  }
 
  if (snode->edittree == nullptr) {
    return false;
  }
 
  if (!WM_drag_is_ID_type(drag, ID_NT)) {
    return false;
  }
 
  if (drag->type == WM_DRAG_ID) {
    const bNodeTree *node_tree = reinterpret_cast<const bNodeTree *>(
        WM_drag_get_local_ID(drag, ID_NT));
    if (!node_tree) {
      return false;
    }
    return node_tree->type == snode->edittree->type;
  }
 
  if (drag->type == WM_DRAG_ASSET) {
    const wmDragAsset *asset_data = WM_drag_get_asset_data(drag, ID_NT);
    if (!asset_data) {
      return false;
    }
    const AssetMetaData *metadata = &asset_data->asset->get_metadata();
    const IDProperty *tree_type = BKE_asset_metadata_idprop_find(metadata, "type");
    if (!tree_type || IDP_Int(tree_type) != snode->edittree->type) {
      return false;
    }
  }
 
  return true;
}
 
static bool node_object_drop_poll(bContext *C, wmDrag *drag, const wmEvent * /*event*/)
{
  return WM_drag_is_ID_type(drag, ID_OB) && !UI_but_active_drop_name(C);
}
 
static bool node_collection_drop_poll(bContext *C, wmDrag *drag, const wmEvent * /*event*/)
{
  return WM_drag_is_ID_type(drag, ID_GR) && !UI_but_active_drop_name(C);
}
 
static bool node_id_im_drop_poll(bContext * /*C*/, wmDrag *drag, const wmEvent * /*event*/)
{
  return WM_drag_is_ID_type(drag, ID_IM);
}
 
static bool node_mask_drop_poll(bContext * /*C*/, wmDrag *drag, const wmEvent * /*event*/)
{
  return WM_drag_is_ID_type(drag, ID_MSK);
}
 
static bool node_material_drop_poll(bContext *C, wmDrag *drag, const wmEvent * /*event*/)
{
  return WM_drag_is_ID_type(drag, ID_MA) && !UI_but_active_drop_name(C);
}
 
static bool node_color_drop_poll(bContext *C, wmDrag *drag, const wmEvent * /*event*/)
{
  return (drag->type == WM_DRAG_COLOR) && !UI_but_active_drop_color(C);
}
 
static bool node_import_file_drop_poll(bContext *C, wmDrag *drag, const wmEvent * /*event*/)
{
  SpaceNode *snode = CTX_wm_space_node(C);
  if (!snode) {
    return false;
  }
  if (!snode->edittree) {
    return false;
  }
  if (snode->edittree->type != NTREE_GEOMETRY) {
    return false;
  }
  if (drag->type != WM_DRAG_PATH) {
    return false;
  }
  const blender::Span<std::string> paths = WM_drag_get_paths(drag);
  for (const StringRef path : paths) {
    if (path.endswith(".csv") || path.endswith(".obj") || path.endswith(".ply") ||
        path.endswith(".stl") || path.endswith(".txt") || path.endswith(".vdb"))
    {
      return true;
    }
  }
  return false;
}
 
static bool node_socket_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
{
  if (drag->type != WM_DRAG_NODE_TREE_INTERFACE) {
    return false;
  }
  SpaceNode *snode = CTX_wm_space_node(C);
  if (!snode || !snode->edittree) {
    return false;
  }
  const bNodeTree *target_ntree = snode->edittree;
 
  auto *drag_data = static_cast<bke::node_interface::bNodeTreeInterfaceItemReference *>(
      drag->poin);
 
  /* Drag only onto node editors of the same node tree. */
  const bNodeTree *source_ntree = drag_data->tree;
  if (target_ntree != source_ntree) {
    return false;
  }
 
  /* Accept only socket items. */
  const bNodeTreeInterfaceSocket *socket =
      bke::node_interface::get_item_as<bNodeTreeInterfaceSocket>(drag_data->item);
  if (socket) {
    /* The check to avoid dragging output sockets is deferred to the
     * operator's poll in order to display a hint tooltip. */
    return true;
  }
 
  /* Unless Ctrl is held, prefer dragging the toggle socket alone from a panel with toggle. */
  if (!(event->modifier & KM_CTRL)) {
    const bNodeTreeInterfacePanel *panel =
        bke::node_interface::get_item_as<bNodeTreeInterfacePanel>(drag_data->item);
    if (panel && panel->header_toggle_socket()) {
      return true;
    }
  }
  return false;
}
 
static bool node_panel_drop_poll(bContext *C, wmDrag *drag, const wmEvent *event)
{
  if (drag->type != WM_DRAG_NODE_TREE_INTERFACE) {
    return false;
  }
  SpaceNode *snode = CTX_wm_space_node(C);
  if (!snode || !snode->edittree) {
    return false;
  }
  const bNodeTree *target_ntree = snode->edittree;
 
  auto *drag_data = static_cast<bke::node_interface::bNodeTreeInterfaceItemReference *>(
      drag->poin);
 
  /* Drag only onto node editors of the same node. */
  const bNodeTree *source_ntree = drag_data->tree;
  if (target_ntree != source_ntree) {
    return false;
  }
 
  /* Accept only panel items. */
  const bNodeTreeInterfacePanel *panel = bke::node_interface::get_item_as<bNodeTreeInterfacePanel>(
      drag_data->item);
  if (panel) {
    /* Unless Ctrl is held, prefer dragging only the toggle socket of a panel with toggle. */
    if (!(event->modifier & KM_CTRL)) {
      if (panel->header_toggle_socket()) {
        return false;
      }
    }
 
    /* The check for whether the panel contains at least one input socket is
     * deferred to the operator's poll in order to display a hint tooltip. */
    return true;
  }
  return false;
}
 
static void node_group_drop_copy(bContext *C, wmDrag *drag, wmDropBox *drop)
{
  ID *id = WM_drag_get_local_ID_or_import_from_asset(C, drag, 0);
 
  RNA_int_set(drop->ptr, "session_uid", int(id->session_uid));
 
  RNA_boolean_set(drop->ptr, "show_datablock_in_node", (drag->type != WM_DRAG_ASSET));
}
 
static void node_id_drop_copy(bContext *C, wmDrag *drag, wmDropBox *drop)
{
  ID *id = WM_drag_get_local_ID_or_import_from_asset(C, drag, 0);
 
  RNA_int_set(drop->ptr, "session_uid", int(id->session_uid));
}
 
static void node_id_im_drop_copy(bContext *C, wmDrag *drag, wmDropBox *drop)
{
  ID *id = WM_drag_get_local_ID_or_import_from_asset(C, drag, 0);
  if (id) {
    RNA_int_set(drop->ptr, "session_uid", int(id->session_uid));
    RNA_struct_property_unset(drop->ptr, "filepath");
    return;
  }
}
 
static void node_import_file_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
{
  io::paths_to_operator_properties(drop->ptr, WM_drag_get_paths(drag));
}
 
static void node_socket_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
{
  if (drag->type != WM_DRAG_NODE_TREE_INTERFACE) {
    return;
  }
 
  auto *drag_data = static_cast<bke::node_interface::bNodeTreeInterfaceItemReference *>(
      drag->poin);
  const bNodeTreeInterfaceSocket *socket =
      bke::node_interface::get_item_as<bNodeTreeInterfaceSocket>(drag_data->item);
  if (!socket) {
    const bNodeTreeInterfacePanel *panel =
        bke::node_interface::get_item_as<bNodeTreeInterfacePanel>(drag_data->item);
    socket = panel->header_toggle_socket();
  }
 
  BLI_assert(socket);
  PropertyRNA *prop = RNA_struct_find_property(drop->ptr, "panel_identifier");
  RNA_property_unset(drop->ptr, prop);
  RNA_string_set(drop->ptr, "socket_identifier", socket->identifier);
}
 
static void node_panel_drop_copy(bContext * /*C*/, wmDrag *drag, wmDropBox *drop)
{
  if (drag->type != WM_DRAG_NODE_TREE_INTERFACE) {
    return;
  }
 
  auto *drag_data = static_cast<bke::node_interface::bNodeTreeInterfaceItemReference *>(
      drag->poin);
  const bNodeTreeInterfacePanel *panel = bke::node_interface::get_item_as<bNodeTreeInterfacePanel>(
      drag_data->item);
 
  BLI_assert(panel);
  PropertyRNA *prop = RNA_struct_find_property(drop->ptr, "socket_identifier");
  RNA_property_unset(drop->ptr, prop);
  RNA_int_set(drop->ptr, "panel_identifier", panel->identifier);
}
 
static std::string node_socket_drop_tooltip(bContext * /*C*/,
                                            wmDrag *drag,
                                            const int /*xy*/[2],
                                            wmDropBox * /*drop*/)
{
  auto *drag_data = static_cast<bke::node_interface::bNodeTreeInterfaceItemReference *>(
      drag->poin);
  const bNodeTreeInterfaceSocket *socket =
      bke::node_interface::get_item_as<bNodeTreeInterfaceSocket>(drag_data->item);
 
  if (socket) {
    return BLI_sprintfN(TIP_("Add \"%s\" Input"), socket->name);
  }
  else {
    const bNodeTreeInterfacePanel *panel =
        bke::node_interface::get_item_as<bNodeTreeInterfacePanel>(drag_data->item);
    socket = panel->header_toggle_socket();
 
    /* Dragging a panel with toggle defaults to dragging the toggle socket.
     * Display a hint with the modifier required to drag the panel. */
    if (socket) {
      return BLI_sprintfN(TIP_("Add \"%s\" Input (Ctrl to add panel)"), socket->name);
    }
  }
  BLI_assert_unreachable();
  return "Error: Unsupported socket.";
}
 
static std::string node_panel_drop_tooltip(bContext * /*C*/,
                                           wmDrag *drag,
                                           const int /*xy*/[2],
                                           wmDropBox * /*drop*/)
{
  auto *drag_data = static_cast<bke::node_interface::bNodeTreeInterfaceItemReference *>(
      drag->poin);
  const bNodeTreeInterfacePanel *panel = bke::node_interface::get_item_as<bNodeTreeInterfacePanel>(
      drag_data->item);
  BLI_assert(panel);
  return BLI_sprintfN(TIP_("Add \"%s\" Panel"), panel->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_group",
                 node_group_drop_poll,
                 node_group_drop_copy,
                 WM_drag_free_imported_drag_ID,
                 nullptr);
  WM_dropbox_add(lb,
                 "NODE_OT_add_image",
                 node_id_im_drop_poll,
                 node_id_im_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);
  WM_dropbox_add(lb,
                 "NODE_OT_add_material",
                 node_material_drop_poll,
                 node_id_drop_copy,
                 WM_drag_free_imported_drag_ID,
                 nullptr);
  WM_dropbox_add(
      lb, "NODE_OT_add_color", node_color_drop_poll, UI_drop_color_copy, nullptr, nullptr);
  WM_dropbox_add(lb,
                 "NODE_OT_add_import_node",
                 node_import_file_drop_poll,
                 node_import_file_drop_copy,
                 nullptr,
                 nullptr);
  WM_dropbox_add(lb,
                 "NODE_OT_add_group_input_node",
                 node_socket_drop_poll,
                 node_socket_drop_copy,
                 nullptr,
                 node_socket_drop_tooltip);
  WM_dropbox_add(lb,
                 "NODE_OT_add_group_input_node",
                 node_panel_drop_poll,
                 node_panel_drop_copy,
                 nullptr,
                 node_panel_drop_tooltip);
}
 
/* ************* end drop *********** */
 
/* add handlers, stuff you only do once or on area/region changes */
static void node_header_region_init(wmWindowManager * /*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;
  const wmNotifier *wmn = params->notifier;
  wmGizmoMap *gzmap = region->runtime->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_ANIMATION:
      if (wmn->data == ND_NLA_ACTCHANGE) {
        ED_region_tag_redraw(region);
      }
      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 (ELEM(wmn->action, NA_RENAME, NA_EDITED)) {
        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;
    case NC_VIEWER_PATH:
      ED_region_tag_redraw(region);
      break;
  }
}
 
}  // namespace blender::ed::space_node
 
/* Outside of blender namespace to avoid Python documentation build error with `ctypes`. */
extern "C" {
const char *node_context_dir[] = {
    "selected_nodes", "active_node", "light", "material", "world", nullptr};
};
 
namespace blender::ed::space_node {
 
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) {
      for (bNode *node : snode->edittree->all_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 = bke::node_get_active(*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->runtime->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 widget-map 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);
  WM_gizmogrouptype_append_and_link(gzmap_type, NODE_GGT_backdrop_box_mask);
  WM_gizmogrouptype_append_and_link(gzmap_type, NODE_GGT_backdrop_ellipse_mask);
  WM_gizmogrouptype_append_and_link(gzmap_type, NODE_GGT_backdrop_split);
}
 
static void node_id_remap(ID *old_id, ID *new_id, SpaceNode *snode)
{
  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_LEGACY) {
    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) {
 
    if (snode->geometry_nodes_tool_tree) {
      if (&snode->geometry_nodes_tool_tree->id == old_id) {
        snode->geometry_nodes_tool_tree = reinterpret_cast<bNodeTree *>(new_id);
      }
    }
 
    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;
      ED_node_set_active_viewer_key(snode);
    }
    else {
      snode->edittree = nullptr;
    }
  }
}
 
static void node_id_remap(ScrArea * /*area*/,
                          SpaceLink *slink,
                          const blender::bke::id::IDRemapper &mappings)
{
  /* Although we should be able to perform all the mappings in a single go this lead to issues when
   * running the python test cases. Somehow the nodetree/edittree weren't updated to the new
   * pointers that generated a SEGFAULT.
   *
   * To move forward we should perhaps remove snode->edittree and snode->nodetree as they are just
   * copies of pointers. All usages should be calling a function that will receive the appropriate
   * instance.
   *
   * We could also move a remap address at a time to use the IDRemapper as that should get closer
   * to cleaner code. See {D13615} for more information about this topic.
   */
  mappings.iter([&](ID *old_id, ID *new_id) {
    node_id_remap(old_id, new_id, reinterpret_cast<SpaceNode *>(slink));
  });
}
 
static void node_foreach_id(SpaceLink *space_link, LibraryForeachIDData *data)
{
  SpaceNode *snode = reinterpret_cast<SpaceNode *>(space_link);
  const int data_flags = BKE_lib_query_foreachid_process_flags_get(data);
  const bool is_readonly = (data_flags & IDWALK_READONLY) != 0;
  const bool allow_pointer_access = (data_flags & IDWALK_NO_ORIG_POINTERS_ACCESS) == 0;
  bool is_embedded_nodetree = snode->id != nullptr && allow_pointer_access &&
                              bke::node_tree_from_id(snode->id) == snode->nodetree;
 
  BKE_LIB_FOREACHID_PROCESS_ID(data, snode->id, IDWALK_CB_DIRECT_WEAK_LINK);
  BKE_LIB_FOREACHID_PROCESS_ID(data, snode->from, IDWALK_CB_DIRECT_WEAK_LINK);
 
  bNodeTreePath *path = static_cast<bNodeTreePath *>(snode->treepath.first);
  BLI_assert(path == nullptr || path->nodetree == snode->nodetree);
 
  if (is_embedded_nodetree) {
    BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, snode->nodetree, IDWALK_CB_EMBEDDED_NOT_OWNING);
    if (path != nullptr) {
      BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, path->nodetree, IDWALK_CB_EMBEDDED_NOT_OWNING);
    }
 
    /* Embedded ID pointers are not remapped (besides exceptions), ensure it still matches
     * actual data. Note that `snode->id` was already processed (and therefore potentially
     * remapped) above. */
    if (!is_readonly) {
      snode->nodetree = (snode->id == nullptr) ? nullptr : bke::node_tree_from_id(snode->id);
      if (path != nullptr) {
        path->nodetree = snode->nodetree;
      }
    }
  }
  else {
    BKE_LIB_FOREACHID_PROCESS_IDSUPER(
        data, snode->nodetree, IDWALK_CB_USER_ONE | IDWALK_CB_DIRECT_WEAK_LINK);
    if (path != nullptr) {
      BKE_LIB_FOREACHID_PROCESS_IDSUPER(
          data, path->nodetree, IDWALK_CB_USER_ONE | IDWALK_CB_DIRECT_WEAK_LINK);
    }
  }
 
  BKE_LIB_FOREACHID_PROCESS_IDSUPER(
      data, snode->geometry_nodes_tool_tree, IDWALK_CB_USER_ONE | IDWALK_CB_DIRECT_WEAK_LINK);
 
  /* Both `snode->id` and `snode->nodetree` have been remapped now, so their data can be
   * accessed. */
  BLI_assert(snode->id == nullptr || snode->nodetree == nullptr ||
             (snode->nodetree->id.flag & ID_FLAG_EMBEDDED_DATA) == 0 ||
             snode->nodetree == bke::node_tree_from_id(snode->id));
 
  /* This is mainly here for readfile case ('lib_link' process), as in such case there is no access
   * to original data allowed, so no way to know whether the SpaceNode nodetree pointer is an
   * embedded one or not. */
  if (!is_readonly && snode->id && !snode->nodetree) {
    is_embedded_nodetree = true;
    snode->nodetree = bke::node_tree_from_id(snode->id);
    if (path != nullptr) {
      path->nodetree = snode->nodetree;
    }
  }
 
  if (path != nullptr) {
    for (path = path->next; path != nullptr; path = path->next) {
      BLI_assert(path->nodetree != nullptr);
      if (allow_pointer_access) {
        BLI_assert((path->nodetree->id.flag & ID_FLAG_EMBEDDED_DATA) == 0);
      }
 
      BKE_LIB_FOREACHID_PROCESS_IDSUPER(
          data, path->nodetree, IDWALK_CB_USER_ONE | IDWALK_CB_DIRECT_WEAK_LINK);
 
      if (path->nodetree == nullptr) {
        BLI_assert(!is_readonly);
        /* Remaining path entries are invalid, remove them. */
        for (bNodeTreePath *path_next; path; path = path_next) {
          path_next = path->next;
          BLI_remlink(&snode->treepath, path);
          MEM_freeN(path);
        }
        break;
      }
    }
  }
  BLI_assert(path == nullptr);
 
  if (!is_readonly) {
    /* `edittree` is just the last in the path, set this directly since the path may have
     * been shortened above. */
    if (snode->treepath.last != nullptr) {
      path = static_cast<bNodeTreePath *>(snode->treepath.last);
      snode->edittree = path->nodetree;
    }
    else {
      snode->edittree = nullptr;
    }
  }
  else {
    /* Only process this pointer in readonly case, otherwise could lead to a bad
     * double-remapping e.g. */
    if (is_embedded_nodetree && snode->edittree == snode->nodetree) {
      BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, snode->edittree, IDWALK_CB_EMBEDDED_NOT_OWNING);
    }
    else {
      BKE_LIB_FOREACHID_PROCESS_IDSUPER(data, snode->edittree, IDWALK_CB_DIRECT_WEAK_LINK);
    }
  }
}
 
static int node_space_subtype_get(ScrArea *area)
{
  SpaceNode *snode = static_cast<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 = static_cast<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(item_src);
  }
}
 
static blender::StringRefNull node_space_name_get(const ScrArea *area)
{
  SpaceNode *snode = static_cast<SpaceNode *>(area->spacedata.first);
  bke::bNodeTreeType *tree_type = bke::node_tree_type_find(snode->tree_idname);
  if (tree_type == nullptr) {
    return IFACE_("Node Editor");
  }
  return tree_type->ui_name;
}
 
static int node_space_icon_get(const ScrArea *area)
{
  SpaceNode *snode = static_cast<SpaceNode *>(area->spacedata.first);
  bke::bNodeTreeType *tree_type = bke::node_tree_type_find(snode->tree_idname);
  if (tree_type == nullptr) {
    return ICON_NODETREE;
  }
  return tree_type->ui_icon;
}
 
static void node_space_blend_read_data(BlendDataReader *reader, SpaceLink *sl)
{
  SpaceNode *snode = (SpaceNode *)sl;
 
  if (snode->gpd) {
    BLO_read_struct(reader, bGPdata, &snode->gpd);
    BKE_gpencil_blend_read_data(reader, snode->gpd);
  }
 
  BLO_read_struct_list(reader, bNodeTreePath, &snode->treepath);
  snode->edittree = nullptr;
  snode->runtime = nullptr;
}
 
static void node_space_blend_write(BlendWriter *writer, SpaceLink *sl)
{
  SpaceNode *snode = (SpaceNode *)sl;
  BLO_write_struct(writer, SpaceNode, snode);
 
  LISTBASE_FOREACH (bNodeTreePath *, path, &snode->treepath) {
    BLO_write_struct(writer, bNodeTreePath, path);
  }
}
 
}  // namespace blender::ed::space_node
 
void ED_spacetype_node()
{
  using namespace blender::ed::space_node;
 
  std::unique_ptr<SpaceType> st = std::make_unique<SpaceType>();
  ARegionType *art;
 
  st->spaceid = SPACE_NODE;
  STRNCPY(st->name, "Node");
 
  st->create = node_create;
  st->free = node_free;
  st->init = node_init;
  st->exit = node_exit;
  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->foreach_id = node_foreach_id;
  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;
  st->space_name_get = node_space_name_get;
  st->space_icon_get = node_space_icon_get;
  st->blend_read_data = node_space_blend_read_data;
  st->blend_read_after_liblink = nullptr;
  st->blend_write = node_space_blend_write;
 
  /* regions: main window */
  art = MEM_callocN<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;
  art->lock = REGION_DRAW_LOCK_ALL;
 
  BLI_addhead(&st->regiontypes, art);
 
  /* regions: header */
  art = MEM_callocN<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: list-view/buttons */
  art = MEM_callocN<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 = MEM_callocN<ARegionType>("spacetype view3d tools region");
  art->regionid = RGN_TYPE_TOOLS;
  art->prefsizex = int(UI_TOOLBAR_WIDTH);
  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);
 
  WM_menutype_add(MEM_dupallocN<MenuType>(__func__, add_catalog_assets_menu_type()));
  WM_menutype_add(MEM_dupallocN<MenuType>(__func__, add_unassigned_assets_menu_type()));
  WM_menutype_add(MEM_dupallocN<MenuType>(__func__, add_root_catalogs_menu_type()));
 
  BKE_spacetype_register(std::move(st));
}