Add-on: much faster processing of BAT progress messages

BAT-packing is a multi-threaded operation, so messages about its progress
are queued up in a thread-safe manner. The modal operator was only handling
4 messages per second, causing major slowdowns when there are lots of
small files to be processed. This is now done much faster, and thus the
UI shouldn't lag behind of the actual submissions progress.

CHANGELOG.md

@@ -4,6 +4,11 @@ This file contains the history of changes to Flamenco. Only changes that might
 be interesting for users are listed here, such as new features and fixes for
 bugs in actually-released versions.
 
+## 3.0 - in development
+
+- Faster & more accurate progress reporting of file submission.
+
+
 ## 3.0-beta3 - released 2022-08-31
 
 - Clean up how version numbers are reported, so that there are no repeats of the

addon/flamenco/operators.py

@@ -3,6 +3,7 @@
 
 import datetime
 import logging
+import time
 from pathlib import Path, PurePosixPath
 from typing import Optional, TYPE_CHECKING
 from urllib3.exceptions import HTTPError, MaxRetryError
@@ -137,6 +138,7 @@ class FLAMENCO_OT_submit_job(FlamencoOpMixin, bpy.types.Operator):
         default=False,
     )
 
+    TIMER_PERIOD = 0.25  # seconds
     timer: Optional[bpy.types.Timer] = None
     packthread: Optional[_PackThread] = None
 
@@ -178,11 +180,22 @@ class FLAMENCO_OT_submit_job(FlamencoOpMixin, bpy.types.Operator):
             # If there is no pack thread running, there isn't much we can do.
             return self._quit(context)
 
-        msg = self.packthread.poll()
-        if not msg:
-            return {"RUNNING_MODAL"}
+        # Limit the time for which messages are processed. If there are no
+        # queued messages, this code stops immediately, but otherwise it will
+        # continue to process until the deadline.
+        deadline = time.monotonic() + 0.9 * self.TIMER_PERIOD
+        num_messages = 0
+        msg = None
+        while time.monotonic() < deadline:
+            msg = self.packthread.poll()
+            if not msg:
+                break
+            num_messages += 1
+            result = self._on_bat_pack_msg(context, msg)
+            if "RUNNING_MODAL" not in result:
+                return result
 
-        return self._on_bat_pack_msg(context, msg)
+        return {"RUNNING_MODAL"}
 
     def _check_manager(self, context: bpy.types.Context) -> str:
         """Check the Manager version & fetch the job storage directory.
@@ -296,7 +309,7 @@ class FLAMENCO_OT_submit_job(FlamencoOpMixin, bpy.types.Operator):
 
         context.window_manager.modal_handler_add(self)
         wm = context.window_manager
-        self.timer = wm.event_timer_add(0.25, window=context.window)
+        self.timer = wm.event_timer_add(self.TIMER_PERIOD, window=context.window)
 
         return {"RUNNING_MODAL"}