Spreadsheet: persistent column storage and data source

A `DataSource` provides columns for the spreadsheet to display.
Every column has a SpreadsheetColumnID as identifier. Columns
are not generated eagerly anymore, instead the main spreadsheet
code can request a column from a data source with an column
identifier. The column identifiers can be stored in DNA and allow us
to store persistent data per column.

On the user level the only thing that changes is that columns are
not shown in alphabetical order anymore. Instead, new columns
are always added on the left. The behavior can be changed,
however I'd prefer not to automate this too much currently. I think
we should just add operators to hide/reorder/resize columns soonish.

Differential Revision: https://developer.blender.org/D10901

1 files changed, 94 insertions, 0 deletions

diff --git a/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.hh b/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.hh
new file mode 100644
index 00000000000..273d39f27bf
--- /dev/null
+++ b/source/blender/editors/space_spreadsheet/spreadsheet_data_source_geometry.hh
@@ -0,0 +1,94 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <mutex>
+
+#include "BLI_resource_scope.hh"
+
+#include "BKE_geometry_set.hh"
+
+#include "spreadsheet_data_source.hh"
+
+struct bContext;
+
+namespace blender::ed::spreadsheet {
+
+class GeometryDataSource : public DataSource {
+ private:
+  Object *object_eval_;
+  const GeometrySet geometry_set_;
+  const GeometryComponent *component_;
+  AttributeDomain domain_;
+
+  /* Some data is computed on the fly only when it is requested. Computing it does not change the
+   * logical state of this data source. Therefore, the corresponding methods are const and need to
+   * be protected with a mutex. */
+  mutable std::mutex mutex_;
+  mutable ResourceScope scope_;
+
+ public:
+  GeometryDataSource(Object *object_eval,
+                     GeometrySet geometry_set,
+                     const GeometryComponentType component_type,
+                     const AttributeDomain domain)
+      : object_eval_(object_eval),
+        geometry_set_(std::move(geometry_set)),
+        component_(geometry_set_.get_component_for_read(component_type)),
+        domain_(domain)
+  {
+  }
+
+  Object *object_eval() const
+  {
+    return object_eval_;
+  }
+
+  Span<int64_t> get_selected_element_indices() const;
+
+  void foreach_default_column_ids(
+      FunctionRef<void(const SpreadsheetColumnID &)> fn) const override;
+
+  std::unique_ptr<ColumnValues> get_column_values(
+      const SpreadsheetColumnID &column_id) const override;
+
+  int tot_rows() const override;
+};
+
+class InstancesDataSource : public DataSource {
+  const GeometrySet geometry_set_;
+  const InstancesComponent *component_;
+
+ public:
+  InstancesDataSource(GeometrySet geometry_set)
+      : geometry_set_(std::move(geometry_set)),
+        component_(geometry_set_.get_component_for_read<InstancesComponent>())
+  {
+  }
+
+  void foreach_default_column_ids(
+      FunctionRef<void(const SpreadsheetColumnID &)> fn) const override;
+
+  std::unique_ptr<ColumnValues> get_column_values(
+      const SpreadsheetColumnID &column_id) const override;
+
+  int tot_rows() const override;
+};
+
+std::unique_ptr<DataSource> data_source_from_geometry(const bContext *C, Object *object_eval);
+
+}  // namespace blender::ed::spreadsheet