add a threading event for pausing the state machine

Author: Nejc Stebe

module_renderer.py

@@ -30,6 +30,7 @@ def __init__(
         run_state: RunState,
         event_bus: EventBus,
         stop_event: threading.Event | None = None,
+        pause_event: threading.Event | None = None,
     ):
         self.codeplainAPI = codeplainAPI
         self.filename = filename
@@ -39,6 +40,7 @@ def __init__(
         self.run_state = run_state
         self.event_bus = event_bus
         self.stop_event = stop_event
+        self.pause_event = pause_event
 
     def _ensure_module_folders_exist(self, module_name: str, first_render_frid: str) -> tuple[str, str]:
         """
@@ -181,6 +183,7 @@ def _build_render_context_for_module(
             event_bus=self.event_bus,
             test_script_timeout=self.args.test_script_timeout,
             stop_event=self.stop_event,
+            pause_event=self.pause_event,
         )
 
     def _render_module(

plain2code.py

@@ -203,6 +203,7 @@ def render(args, run_state: RunState, event_bus: EventBus):  # noqa: C901
     _check_connection(codeplainAPI)
 
     stop_event = threading.Event()
+    pause_event = threading.Event()
     signal.signal(signal.SIGTERM, lambda _signum, _frame: stop_event.set())
 
     module_renderer = ModuleRenderer(
@@ -214,6 +215,7 @@ def render(args, run_state: RunState, event_bus: EventBus):  # noqa: C901
         run_state,
         event_bus,
         stop_event=stop_event,
+        pause_event=pause_event,
     )
 
     render_error: list[Exception] = []
@@ -245,6 +247,7 @@ def run_render():
             conformance_tests_script=args.conformance_tests_script,
             prepare_environment_script=args.prepare_environment_script,
             state_machine_version=system_config.client_version,
+            pause_event=pause_event,
             css_path="styles.css",
         )
         app.run()

plain2code_events.py

@@ -63,8 +63,3 @@ class RenderModuleStarted(BaseEvent):
     module_name: str
 
 
-@dataclass
-class PauseRequested(BaseEvent):
-    """Event emitted when the user requests to pause rendering."""
-
-    pass

render_machine/code_renderer.py

@@ -1,3 +1,4 @@
+import time
 from copy import deepcopy
 
 from transitions.extensions.diagrams import HierarchicalGraphMachine
@@ -6,6 +7,8 @@
 from render_machine.render_context import RenderContext
 from render_machine.state_machine_config import StateMachineConfig, States
 
+PAUSE_POLL_INTERVAL_SECONDS = 1
+
 
 class CodeRenderer:
     """Main code renderer class that orchestrates the code generation workflow using a hierarchical state machine."""
@@ -35,7 +38,12 @@ def run(self):
         self.render_context.event_bus.publish(RenderModuleStarted(module_name=self.render_context.module_name))
         previous_action_payload = None
         previous_state = None
+
         while True:
+            if self.render_context.pause_event and self.render_context.pause_event.is_set():
+                while self.render_context.pause_event.is_set():
+                    time.sleep(PAUSE_POLL_INTERVAL_SECONDS)
+
             self.render_context.event_bus.publish(
                 RenderStateUpdated(
                     state=self.render_context.state,

render_machine/render_context.py

@@ -54,6 +54,7 @@ def __init__(
         event_bus: EventBus,
         test_script_timeout: Optional[int] = None,
         stop_event: Optional[threading.Event] = None,
+        pause_event: Optional[threading.Event] = None,
     ):
         self.codeplain_api: CodeplainAPI = codeplain_api
         self.memory_manager = memory_manager
@@ -77,6 +78,7 @@ def __init__(
         self.run_state = run_state
         self.event_bus = event_bus
         self.stop_event = stop_event
+        self.pause_event = pause_event
         self.script_execution_history = ScriptExecutionHistory()
         self.starting_frid = None
         self.test_script_timeout = test_script_timeout

tui/plain2code_tui.py

@@ -10,7 +10,6 @@
 from event_bus import EventBus
 from plain2code_events import (
     LogMessageEmitted,
-    PauseRequested,
     RenderCompleted,
     RenderContextSnapshot,
     RenderFailed,
@@ -66,6 +65,7 @@ def __init__(
         conformance_tests_script: str,
         prepare_environment_script: str,
         state_machine_version: str,
+        pause_event: threading.Event | None = None,
         **kwargs,
     ):
         super().__init__(**kwargs)
@@ -77,6 +77,7 @@ def __init__(
         self.conformance_tests_script: Optional[str] = conformance_tests_script
         self.prepare_environment_script: Optional[str] = prepare_environment_script
         self.state_machine_version = state_machine_version
+        self.pause_event = pause_event
         self._render_finished = False
 
         # Initialize state handlers
@@ -283,9 +284,13 @@ async def action_copy_selection(self) -> None:
 
     def action_pause(self) -> None:
         """Handle ctrl+shift+p: request the render machine to pause."""
-        if not self._render_finished:
+        if not self._render_finished and self.pause_event is not None:
             set_frid_progress_to_paused(self)
-            self.event_bus.publish(PauseRequested())
+
+            if self.pause_event.is_set():
+                self.pause_event.clear()
+            else:
+                self.pause_event.set()
 
     def action_enter_exit(self) -> None:
         """Handle enter: exit the TUI only after rendering has finished."""