Add generic converter adapter hooks

Co-authored-by: Codex <codex@openai.com>

generic_converter/adapter.py

@@ -1,6 +1,7 @@
 from abc import ABC, abstractmethod
 from collections.abc import Iterable, Sequence
 from pathlib import Path
+from typing import Any
 
 from .utils import ConversionTask, FeatureSpec
 
@@ -26,7 +27,36 @@ class BaseAdapter(ABC):
         """Build conversion tasks from dataset-specific inputs."""
 
     @abstractmethod
-    def load_subset(
-        self, task: ConversionTask
-    ) -> Iterable[Sequence[dict]]:
+    def load_subset(self, task: ConversionTask) -> Iterable[Any]:
         """Yield LeRobot episodes for one raw input path."""
+
+    def create_dataset(self, task: ConversionTask):
+        """Create the temporary LeRobot dataset for one conversion task."""
+        from lerobot.datasets import LeRobotDataset
+
+        return LeRobotDataset.create(
+            repo_id=task.local_repo_id,
+            root=task.output_path,
+            fps=self.fps,
+            robot_type=self.robot_type,
+            features=self.features,
+        )
+
+    def save_episode(
+        self,
+        dataset: Any,
+        episode_data: Sequence[dict],
+        task: ConversionTask,
+    ) -> bool:
+        """Save one episode to the temporary dataset.
+
+        Adapters can override this when a dataset needs extra per-episode
+        arguments or a non-standard writer.
+        """
+        for frame in episode_data:
+            dataset.add_frame(frame)
+        dataset.save_episode()
+        return True
+
+    def get_episode_length(self, episode_data: Any) -> int:
+        return len(episode_data)