feat: cleaner public api (#54)

Closes #53

### Summary of Changes

Define a small public interface consisting of
* `safeds_runner.file_mtime`,
* `safeds_runner.memoized_call`,
* `safeds_runner.save_placeholder`.

These are used by the code generator of the
[DSL](https://github.com/Safe-DS/DSL).

src/safeds_runner/__init__.py

@@ -1 +1,9 @@
 """A runner for the Python code generated from Safe-DS programs."""
+
+from .server._pipeline_manager import file_mtime, memoized_call, save_placeholder
+
+__all__ = [
+    "file_mtime",
+    "memoized_call",
+    "save_placeholder",
+]

src/safeds_runner/server/pipeline_manager.py → src/safeds_runner/server/_pipeline_manager.py

@@ -15,8 +15,8 @@
 
 import stack_data
 
-from safeds_runner.server.memoization_map import MemoizationMap
-from safeds_runner.server.messages import (
+from ._memoization_map import MemoizationMap
+from ._messages import (
     Message,
     MessageDataProgram,
     create_placeholder_description,
@@ -26,7 +26,7 @@
     message_type_runtime_error,
     message_type_runtime_progress,
 )
-from safeds_runner.server.module_manager import InMemoryFinder
+from ._module_manager import InMemoryFinder
 
 
 class PipelineManager:
@@ -288,7 +288,7 @@ def execute(self) -> None:
 current_pipeline: PipelineProcess | None = None
 
 
-def runner_save_placeholder(placeholder_name: str, value: Any) -> None:
+def save_placeholder(placeholder_name: str, value: Any) -> None:
     """
     Save a placeholder for the current running pipeline.
 
@@ -303,7 +303,7 @@ def runner_save_placeholder(placeholder_name: str, value: Any) -> None:
         current_pipeline.save_placeholder(placeholder_name, value)
 
 
-def runner_memoized_function_call(
+def memoized_call(
     function_name: str,
     function_callable: typing.Callable,
     parameters: list[Any],
@@ -336,7 +336,7 @@ def runner_memoized_function_call(
     return memoization_map.memoized_function_call(function_name, function_callable, parameters, hidden_parameters)
 
 
-def runner_filemtime(filename: str) -> int | None:
+def file_mtime(filename: str) -> int | None:
     """
     Get the last modification timestamp of the provided file.
 

src/safeds_runner/server/server.py → src/safeds_runner/server/_server.py

@@ -8,15 +8,17 @@
 import hypercorn.asyncio
 import quart.app
 
-from safeds_runner.server import messages
-from safeds_runner.server.json_encoder import SafeDsEncoder
-from safeds_runner.server.messages import (
+from ._json_encoder import SafeDsEncoder
+from ._messages import (
     Message,
     create_placeholder_value,
     message_type_placeholder_value,
+    message_types,
     parse_validate_message,
+    validate_placeholder_query_message_data,
+    validate_program_message_data,
 )
-from safeds_runner.server.pipeline_manager import PipelineManager
+from ._pipeline_manager import PipelineManager
 
 
 def create_flask_app() -> quart.app.Quart:
@@ -108,7 +110,7 @@ async def _ws_main_foreground(
                     pipeline_manager.shutdown()
                     sys.exit(0)
                 case "program":
-                    program_data, invalid_message = messages.validate_program_message_data(received_object.data)
+                    program_data, invalid_message = validate_program_message_data(received_object.data)
                     if program_data is None:
                         logging.error("Invalid message data specified in: %s (%s)", received_message, invalid_message)
                         await output_queue.put(None)
@@ -119,7 +121,7 @@ async def _ws_main_foreground(
                     pipeline_manager.execute_pipeline(program_data, received_object.id)
                 case "placeholder_query":
                     # For this query, a response can be directly sent to the requesting connection
-                    placeholder_query_data, invalid_message = messages.validate_placeholder_query_message_data(
+                    placeholder_query_data, invalid_message = validate_placeholder_query_message_data(
                         received_object.data,
                     )
                     if placeholder_query_data is None:
@@ -173,7 +175,7 @@ async def _ws_main_foreground(
                             ),
                         )
                 case _:
-                    if received_object.type not in messages.message_types:
+                    if received_object.type not in message_types:
                         logging.warning("Invalid message type: %s", received_object.type)
 
     @staticmethod

src/safeds_runner/server/main.py

@@ -2,7 +2,7 @@
 
 import logging
 
-from safeds_runner.server.server import SafeDsServer
+from ._server import SafeDsServer
 
 
 def start_server(port: int) -> None:

tests/safeds_runner/server/test_json_encoder.py

@@ -6,7 +6,7 @@
 import pytest
 from safeds.data.image.containers import Image
 from safeds.data.tabular.containers import Table
-from safeds_runner.server.json_encoder import SafeDsEncoder
+from safeds_runner.server._json_encoder import SafeDsEncoder
 
 
 @pytest.mark.parametrize(

tests/safeds_runner/server/test_memoization.py

@@ -7,15 +7,15 @@
 from typing import Any
 
 import pytest
-from safeds_runner.server import pipeline_manager
-from safeds_runner.server.memoization_map import (
+from safeds_runner.server import _pipeline_manager
+from safeds_runner.server._memoization_map import (
     MemoizationMap,
     MemoizationStats,
     _convert_list_to_tuple,
     _get_size_of_value,
 )
-from safeds_runner.server.messages import MessageDataProgram, ProgramMainInformation
-from safeds_runner.server.pipeline_manager import PipelineProcess, runner_filemtime, runner_memoized_function_call
+from safeds_runner.server._messages import MessageDataProgram, ProgramMainInformation
+from safeds_runner.server._pipeline_manager import PipelineProcess, file_mtime, memoized_call
 
 
 @pytest.mark.parametrize(
@@ -32,25 +32,25 @@ def test_memoization_already_present_values(
     hidden_params: list,
     expected_result: Any,
 ) -> None:
-    pipeline_manager.current_pipeline = PipelineProcess(
+    _pipeline_manager.current_pipeline = PipelineProcess(
         MessageDataProgram({}, ProgramMainInformation("", "", "")),
         "",
         Queue(),
         {},
         MemoizationMap({}, {}),
     )
-    pipeline_manager.current_pipeline.get_memoization_map()._map_values[(
+    _pipeline_manager.current_pipeline.get_memoization_map()._map_values[(
         function_name,
         _convert_list_to_tuple(params),
         _convert_list_to_tuple(hidden_params),
     )] = expected_result
-    pipeline_manager.current_pipeline.get_memoization_map()._map_stats[function_name] = MemoizationStats(
+    _pipeline_manager.current_pipeline.get_memoization_map()._map_stats[function_name] = MemoizationStats(
         [time.perf_counter_ns()],
         [],
         [],
         [sys.getsizeof(expected_result)],
     )
-    result = pipeline_manager.runner_memoized_function_call(function_name, lambda *_: None, params, hidden_params)
+    result = _pipeline_manager.memoized_call(function_name, lambda *_: None, params, hidden_params)
     assert result == expected_result
 
 
@@ -69,30 +69,30 @@ def test_memoization_not_present_values(
     hidden_params: list,
     expected_result: Any,
 ) -> None:
-    pipeline_manager.current_pipeline = PipelineProcess(
+    _pipeline_manager.current_pipeline = PipelineProcess(
         MessageDataProgram({}, ProgramMainInformation("", "", "")),
         "",
         Queue(),
         {},
         MemoizationMap({}, {}),
     )
     # Save value in map
-    result = runner_memoized_function_call(function_name, function, params, hidden_params)
+    result = memoized_call(function_name, function, params, hidden_params)
     assert result == expected_result
     # Test if value is actually saved by calling another function that does not return the expected result
-    result2 = runner_memoized_function_call(function_name, lambda *_: None, params, hidden_params)
+    result2 = memoized_call(function_name, lambda *_: None, params, hidden_params)
     assert result2 == expected_result
 
 
 def test_file_mtime_exists() -> None:
     with tempfile.NamedTemporaryFile() as file:
-        file_mtime = runner_filemtime(file.name)
-        assert file_mtime is not None
+        mtime = file_mtime(file.name)
+        assert mtime is not None
 
 
 def test_file_mtime_not_exists() -> None:
-    file_mtime = runner_filemtime(f"file_not_exists.{datetime.now(tz=UTC).timestamp()}")
-    assert file_mtime is None
+    mtime = file_mtime(f"file_not_exists.{datetime.now(tz=UTC).timestamp()}")
+    assert mtime is None
 
 
 @pytest.mark.parametrize(

tests/safeds_runner/server/test_pipeline_manager_type_conversion.py

@@ -1,7 +1,7 @@
 from typing import Any
 
 import pytest
-from safeds_runner.server.pipeline_manager import _get_placeholder_type
+from safeds_runner.server._pipeline_manager import _get_placeholder_type
 
 
 @pytest.mark.parametrize(

tests/safeds_runner/server/test_websocket_mock.py

@@ -12,8 +12,8 @@
 import simple_websocket
 from quart.testing.connections import WebsocketDisconnectError
 from safeds.data.tabular.containers import Table
-from safeds_runner.server.json_encoder import SafeDsEncoder
-from safeds_runner.server.messages import (
+from safeds_runner.server._json_encoder import SafeDsEncoder
+from safeds_runner.server._messages import (
     Message,
     MessageQueryInformation,
     QueryWindow,
@@ -28,7 +28,7 @@
     validate_placeholder_query_message_data,
     validate_program_message_data,
 )
-from safeds_runner.server.server import SafeDsServer
+from safeds_runner.server._server import SafeDsServer
 
 
 @pytest.mark.parametrize(
@@ -369,9 +369,9 @@ async def test_should_execute_pipeline_return_exception(
                         "code": {
                             "": {
                                 "gen_test_a": (
-                                    "import safeds_runner.server.pipeline_manager\n\ndef pipe():\n\tvalue1 ="
-                                    " 1\n\tsafeds_runner.server.pipeline_manager.runner_save_placeholder('value1',"
-                                    " value1)\n\tsafeds_runner.server.pipeline_manager.runner_save_placeholder('obj',"
+                                    "import safeds_runner\n\ndef pipe():\n\tvalue1 ="
+                                    " 1\n\tsafeds_runner.save_placeholder('value1',"
+                                    " value1)\n\tsafeds_runner.save_placeholder('obj',"
                                     " object())\n"
                                 ),
                                 "gen_test_a_pipe": (