Split MjSpec out into header to allow use by other pybind modules.

This should enable other pybind modules to accept arguments of type MjSpec.

PiperOrigin-RevId: 745580987
Change-Id: I435a8d264149369e3fbee14c5d2c628ef74b2541

python/mujoco/specs_wrapper.h

@@ -0,0 +1,45 @@
+// Copyright 2024 DeepMind Technologies Limited
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "raw.h"
+#include <pybind11/cast.h>
+#include <pybind11/pybind11.h>
+#include <pybind11/pytypes.h>
+#include <pybind11/stl.h>
+
+namespace py = ::pybind11;
+
+namespace mujoco::python {
+
+struct MjSpec {
+  MjSpec();
+  MjSpec(raw::MjSpec* ptr, const py::dict& assets_ = {});
+
+  // copy constructor and assignment
+  MjSpec(const MjSpec& other);
+  MjSpec& operator=(const MjSpec& other);
+
+  // move constructor and move assignment
+  MjSpec(MjSpec&& other);
+  MjSpec& operator=(MjSpec&& other);
+  ~MjSpec();
+
+  raw::MjModel* Compile();
+
+  raw::MjSpec* ptr;
+  py::dict assets;
+  bool override_assets = true;
+  MjSpec* parent = nullptr;
+};
+}  // namespace mujoco::python