From 0c8b6a80a0c484c87e6f17fce36d1629b0889221 Mon Sep 17 00:00:00 2001
From: David Manthey <david.manthey@kitware.com>
Date: Thu, 2 Feb 2023 08:50:48 -0500
Subject: [PATCH] Fix an issue with the multi source last open cache.

---
 CHANGELOG.md                                  |  2 +-
 .../large_image_source_multi/__init__.py      | 23 +++++++++++--------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 472b9d68f..536854944 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,7 @@
 - ICC color profile support ([#1037](../../pull/1037), [#1043](../../pull/1043))
 
 ### Improvements
-- Speed up generating tiles for some multi source files ([#1035](../../pull/1035))
+- Speed up generating tiles for some multi source files ([#1035](../../pull/1035), [#1047](../../pull/1047))
 - Render item lists faster ([#1036](../../pull/1036))
 - Reduce bioformats source memory usage ([#1038](../../pull/1038))
 - Better pick the largest image from bioformats ([#1039](../../pull/1039), [#1040](../../pull/1040))
diff --git a/sources/multi/large_image_source_multi/__init__.py b/sources/multi/large_image_source_multi/__init__.py
index 1c9eef3a2..7e385faa3 100644
--- a/sources/multi/large_image_source_multi/__init__.py
+++ b/sources/multi/large_image_source_multi/__init__.py
@@ -5,6 +5,7 @@
 import math
 import os
 import re
+import threading
 import warnings
 from pathlib import Path
 
@@ -388,6 +389,7 @@ def __init__(self, path, **kwargs):
         super().__init__(path, **kwargs)
 
         self._largeImagePath = self._getLargeImagePath()
+        self._lastOpenSourceLock = threading.RLock()
         if not os.path.isfile(self._largeImagePath):
             try:
                 possibleYaml = self._largeImagePath.split('multi://', 1)[-1]
@@ -804,10 +806,11 @@ def _openSource(self, source, params=None):
         :param params: a dictionary of parameters to pass to the open call.
         :returns: a tile source.
         """
-        if (hasattr(self, '_lastOpenSource') and
-                self._lastOpenSource['source'] == source and
-                self._lastOpenSource['params'] == params):
-            return self._lastOpenSource['ts']
+        with self._lastOpenSourceLock:
+            if (hasattr(self, '_lastOpenSource') and
+                    self._lastOpenSource['source'] == source and
+                    self._lastOpenSource['params'] == params):
+                return self._lastOpenSource['ts']
         if not len(large_image.tilesource.AvailableTileSources):
             large_image.tilesource.loadTileSources()
         if ('sourceName' not in source or
@@ -815,14 +818,16 @@ def _openSource(self, source, params=None):
             openFunc = large_image.open
         else:
             openFunc = large_image.tilesource.AvailableTileSources[source['sourceName']]
-        self._lastOpenSource = {
-            'source': source,
-            'params': params,
-        }
+        origParams = params
         if params is None:
             params = source.get('params', {})
         ts = openFunc(source['path'], **params)
-        self._lastOpenSource['ts'] = ts
+        with self._lastOpenSourceLock:
+            self._lastOpenSource = {
+                'source': source,
+                'params': origParams,
+                'ts': ts
+            }
         return ts
 
     def getAssociatedImage(self, imageKey, *args, **kwargs):