Codegen more of our Python arrow serialization (#6154)

### What
This implements codegen of python arrow serialization in cases where we
can just delegate to our datatypes.

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using examples from latest `main` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/6154?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/6154?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG
* [x] If applicable, add a new check to the [release
checklist](https://github.com/rerun-io/rerun/blob/main/tests/python/release_checklist)!

- [PR Build Summary](https://build.rerun.io/pr/6154)
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

To run all checks from `main`, comment on the PR with `@rerun-bot
full-check`.

crates/re_types_builder/src/codegen/python/mod.rs

@@ -1841,7 +1841,7 @@ fn np_dtype_from_type(t: &Type) -> Option<&'static str> {
 /// Only implemented for some cases.
 fn quote_arrow_serialization(
  reporter: &Reporter,
- _objects: &Objects,
+ objects: &Objects,
  obj: &Object,
 ) -> Result<String, String> {
  let Object { name, .. } = obj;
@@ -1888,7 +1888,51 @@ fn quote_arrow_serialization(
  }
  }
 
- Err("We lack codegen for arrow-serialization of structs".to_owned())
+ let mut code = String::new();
+
+ for field in &obj.fields {
+ let Type::Object(field_fqname) = &field.typ else {
+ return Err(
+ "We lack codegen for arrow-serialization of general structs".to_owned()
+ );
+ };
+ if let Some(last_dot) = field_fqname.rfind('.') {
+ let mod_path = &field_fqname[..last_dot];
+ let field_type_name = &field_fqname[last_dot + 1..];
+ code.push_indented(
+ 0,
+ format!("from {mod_path} import {field_type_name}Batch"),
+ 2,
+ );
+ }
+ }
+
+ code.push_indented(0, &format!("if isinstance(data, {name}):"), 1);
+ code.push_indented(1, "data = [data]", 2);
+
+ code.push_indented(0, "return pa.StructArray.from_arrays(", 1);
+ code.push_indented(1, "[", 1);
+ for field in &obj.fields {
+ let Type::Object(field_fqname) = &field.typ else {
+ return Err(
+ "We lack codegen for arrow-serialization of general structs".to_owned()
+ );
+ };
+ let field_obj = &objects[field_fqname];
+ let field_type_name = &field_obj.name;
+ let field_name = &field.name;
+ let field_batch_type = format!("{field_type_name}Batch");
+ // let field_batch_type = format!("datatypes.{field_type_name}Batch");
+ let field_array = format!("[x.{field_name} for x in data]");
+ let field_fwd =
+ format!("{field_batch_type}({field_array}).as_arrow_array().storage,");
+ code.push_indented(2, &field_fwd, 1);
+ }
+ code.push_indented(1, "],", 1);
+ code.push_indented(1, "fields=list(data_type),", 1);
+ code.push_indented(0, ")", 1);
+
+ Ok(code)
  }
 
  ObjectClass::Enum => {

rerun_py/rerun_sdk/rerun/datatypes/rotation_axis_angle_ext.py

@@ -2,10 +2,8 @@
 
 from typing import TYPE_CHECKING, Any
 
-import pyarrow as pa
-
 if TYPE_CHECKING:
- from . import Angle, AngleLike, RotationAxisAngleArrayLike, Vec3DLike
+ from . import Angle, AngleLike, Vec3DLike
 
 
 class RotationAxisAngleExt:
@@ -58,21 +56,3 @@ def angle__field_converter_override(x: AngleLike) -> Angle:
  return x
  else:
  return Angle(rad=x)
-
- @staticmethod
- def native_to_pa_array_override(data: RotationAxisAngleArrayLike, data_type: pa.DataType) -> pa.Array:
- from . import AngleBatch, RotationAxisAngle, Vec3DBatch
-
- if isinstance(data, RotationAxisAngle):
- data = [data]
-
- axis_pa_array = Vec3DBatch._native_to_pa_array([rotation.axis for rotation in data], data_type["axis"].type)
- angle_pa_arr = AngleBatch._native_to_pa_array([rotation.angle for rotation in data], data_type["angle"].type)
-
- return pa.StructArray.from_arrays(
- [
- axis_pa_array,
- angle_pa_arr,
- ],
- fields=list(data_type),
- )