Fix infinite while loops with a thread is alive check

CHANGELOG.rst

@@ -7,6 +7,11 @@ Changelog
 .. This document is user facing. Please word the changes in such a way
 .. that users understand how the changes affect the new version.
 
+version 0.5.1-dev
+-----------------
++ Threaded reading and writing do no longer block exiting when an exception
+  occurs in the main thread.
+
 version 0.5.0
 -----------------
 + Wheels are now build for MacOS arm64 architectures.

src/zlib_ng/gzip_ng_threaded.py

@@ -101,6 +101,7 @@ def __init__(self, filename, queue_size=2, block_size=1024 * 1024):
         self.worker = threading.Thread(target=self._decompress)
         self._closed = False
         self.running = True
+        self._calling_thread = threading.current_thread()
         self.worker.start()
 
     def _check_closed(self, msg=None):
@@ -110,15 +111,15 @@ def _check_closed(self, msg=None):
     def _decompress(self):
         block_size = self.block_size
         block_queue = self.queue
-        while self.running:
+        while self.running and self._calling_thread.is_alive():
             try:
                 data = self.fileobj.read(block_size)
             except Exception as e:
                 self.exception = e
                 return
             if not data:
                 return
-            while self.running:
+            while self.running and self._calling_thread.is_alive():
                 try:
                     block_queue.put(data, timeout=0.05)
                     break
@@ -215,6 +216,7 @@ def __init__(self,
         if "b" not in mode:
             mode += "b"
         self.lock = threading.Lock()
+        self._calling_thread = threading.current_thread()
         self.exception: Optional[Exception] = None
         self.level = level
         self.previous_block = b""
@@ -349,7 +351,7 @@ def _compress(self, index: int):
         in_queue = self.input_queues[index]
         out_queue = self.output_queues[index]
         compressor: zlib_ng._ParallelCompress = self.compressors[index]
-        while True:
+        while self._calling_thread.is_alive():
             try:
                 data, zdict = in_queue.get(timeout=0.05)
             except queue.Empty:
@@ -372,7 +374,7 @@ def _write(self):
         fp = self.raw
         total_crc = 0
         size = 0
-        while True:
+        while self._calling_thread.is_alive():
             out_index = index % self.threads
             output_queue = output_queues[out_index]
             try:
@@ -397,7 +399,7 @@ def _compress_and_write(self):
         size = 0
         in_queue = self.input_queues[0]
         compressor = self.compressors[0]
-        while True:
+        while self._calling_thread.is_alive():
             try:
                 data, zdict = in_queue.get(timeout=0.05)
             except queue.Empty: