From bf234445af1ddcfbed03efc54e320949777ffd69 Mon Sep 17 00:00:00 2001
From: Sergey Krashevich <svk@svk.su>
Date: Thu, 6 Jul 2023 17:09:56 +0300
Subject: [PATCH] Add thread-safety to LimitedQueue by implementing a lock for
 put and get methods

---
 frigate/util.py | 36 ++++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/frigate/util.py b/frigate/util.py
index cc9bb03c9..3a8746100 100755
--- a/frigate/util.py
+++ b/frigate/util.py
@@ -1239,29 +1239,33 @@ class LimitedQueue(FFQueue):
         self.size = multiprocessing.RawValue(
             ctypes.c_int, 0
         )  # Add a counter for the number of items in the queue
+        self.lock = multiprocessing.Lock()  # Add a lock for thread-safety
 
     def put(self, x, block=True, timeout=DEFAULT_TIMEOUT):
-        if self.maxsize > 0 and self.size.value >= self.maxsize:
-            if block:
-                start_time = time.time()
-                while self.size.value >= self.maxsize:
-                    remaining = timeout - (time.time() - start_time)
-                    if remaining <= 0.0:
-                        raise Full
-                    time.sleep(min(remaining, 0.1))
-            else:
-                raise Full
-        self.size.value += 1
+        with self.lock:  # Ensure thread-safety
+            if self.maxsize > 0 and self.size.value >= self.maxsize:
+                if block:
+                    start_time = time.time()
+                    while self.size.value >= self.maxsize:
+                        remaining = timeout - (time.time() - start_time)
+                        if remaining <= 0.0:
+                            raise Full
+                        time.sleep(min(remaining, 0.1))
+                else:
+                    raise Full
+            self.size.value += 1
         return super().put(x, block=block, timeout=timeout)
 
     def get(self, block=True, timeout=DEFAULT_TIMEOUT):
-        if self.size.value <= 0 and not block:
-            raise Empty
-        self.size.value -= 1
-        return super().get(block=block, timeout=timeout)
+        item = super().get(block=block, timeout=timeout)
+        with self.lock:  # Ensure thread-safety
+            if self.size.value <= 0 and not block:
+                raise Empty
+            self.size.value -= 1
+        return item
 
     def qsize(self):
-        return self.size
+        return self.size.value  # Return the value, not the RawValue object
 
     def empty(self):
         return self.qsize() == 0