From 1efc94bb2f7b0321935ce6564b23d5d92ee41594 Mon Sep 17 00:00:00 2001
From: Julian Eisel <julian@blender.org>
Date: Wed, 9 Nov 2022 18:34:31 +0100
Subject: Asset System: New core type to represent assets
 (`AssetRepresenation`)

Introduces a new `AssetRepresentation` type, as a runtime only container
to hold asset information. It is supposed to become _the_ main way to
represent and refer to assets in the asset system, see T87235. It can
store things like the asset name, asset traits, preview and other asset
metadata.

Technical documentation:
https://wiki.blender.org/wiki/Source/Architecture/Asset_System/Back_End#Asset_Representation.

By introducing a proper asset representation type, we do an important
step away from the previous, non-optimal representation of assets as
files in the file browser backend, and towards the asset system as
backend. It should replace the temporary & hacky `AssetHandle` design in
the near future. Note that the loading of asset data still happens
through the file browser backend, check the linked to Wiki page for more
information on that.

As a side-effect, asset metadata isn't stored in file browser file
entries when browsing with link/append anymore. Don't think this was
ever used, but scripts may have accessed this. Can be brought back if
there's a need for it.
---
 .../blenkernel/intern/asset_representation.cc      | 98 ++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 source/blender/blenkernel/intern/asset_representation.cc

(limited to 'source/blender/blenkernel/intern/asset_representation.cc')

diff --git a/source/blender/blenkernel/intern/asset_representation.cc b/source/blender/blenkernel/intern/asset_representation.cc
new file mode 100644
index 00000000000..bbaa634d5ad
--- /dev/null
+++ b/source/blender/blenkernel/intern/asset_representation.cc
@@ -0,0 +1,98 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/** \file
+ * \ingroup bke
+ */
+
+#include <stdexcept>
+
+#include "DNA_ID.h"
+#include "DNA_asset_types.h"
+
+#include "BKE_asset.h"
+#include "BKE_asset_representation.hh"
+
+namespace blender::bke {
+
+AssetRepresentation::AssetRepresentation(StringRef name, std::unique_ptr<AssetMetaData> metadata)
+    : is_local_id_(false), external_asset_()
+{
+  external_asset_.name = name;
+  external_asset_.metadata_ = std::move(metadata);
+}
+
+AssetRepresentation::AssetRepresentation(ID &id) : is_local_id_(true), local_asset_id_(&id)
+{
+  if (!id.asset_data) {
+    throw std::invalid_argument("Passed ID is not an asset");
+  }
+}
+
+AssetRepresentation::AssetRepresentation(AssetRepresentation &&other)
+    : is_local_id_(other.is_local_id_)
+{
+  if (is_local_id_) {
+    local_asset_id_ = other.local_asset_id_;
+    other.local_asset_id_ = nullptr;
+  }
+  else {
+    external_asset_ = std::move(other.external_asset_);
+  }
+}
+
+AssetRepresentation::~AssetRepresentation()
+{
+  if (!is_local_id_) {
+    external_asset_.~ExternalAsset();
+  }
+}
+
+StringRefNull AssetRepresentation::get_name() const
+{
+  if (is_local_id_) {
+    return local_asset_id_->name + 2;
+  }
+
+  return external_asset_.name;
+}
+
+AssetMetaData &AssetRepresentation::get_metadata() const
+{
+  return is_local_id_ ? *local_asset_id_->asset_data : *external_asset_.metadata_;
+}
+
+bool AssetRepresentation::is_local_id() const
+{
+  return is_local_id_;
+}
+
+}  // namespace blender::bke
+
+/* ---------------------------------------------------------------------- */
+/** \name C-API
+ * \{ */
+
+using namespace blender;
+
+const char *BKE_asset_representation_name_get(const AssetRepresentation *asset_handle)
+{
+  const bke::AssetRepresentation *asset = reinterpret_cast<const bke::AssetRepresentation *>(
+      asset_handle);
+  return asset->get_name().c_str();
+}
+
+AssetMetaData *BKE_asset_representation_metadata_get(const AssetRepresentation *asset_handle)
+{
+  const bke::AssetRepresentation *asset = reinterpret_cast<const bke::AssetRepresentation *>(
+      asset_handle);
+  return &asset->get_metadata();
+}
+
+bool BKE_asset_representation_is_local_id(const AssetRepresentation *asset_handle)
+{
+  const bke::AssetRepresentation *asset = reinterpret_cast<const bke::AssetRepresentation *>(
+      asset_handle);
+  return asset->is_local_id();
+}
+
+/** \} */
-- 
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