fix ffmpeg

xlib/io/IOThreadLinesReader.py

@@ -0,0 +1,56 @@
+import threading
+import time
+from io import IOBase
+from typing import List
+from collections import deque
+
+class IOThreadLinesReader:
+    """
+    continuously reads lines from IO in background thread.
+    """
+
+    def __init__(self, io : IOBase, max_lines=None):
+        self._io = io
+        self._lock = threading.Lock()
+        self._lines = deque(maxlen=max_lines)
+
+        threading.Thread(target=self._proc, daemon=True).start()
+
+    def _proc(self):
+        io = self._io
+        lock = self._lock
+        lines = self._lines
+
+        while not io.closed and io.readable():
+            line = io.readline()
+            lock.acquire()
+            lines.append(line.decode('utf-8').rstrip())
+            lock.release()
+            if len(line) == 0:
+                break
+            time.sleep(0.01)
+
+    def get_lines(self, wait_new=True, till_eof=False) -> List[str]:
+        """
+        """
+        lock = self._lock
+        lines = self._lines
+
+        result = []
+        while True:
+
+            if len(lines) != 0:
+                lock.acquire()
+                result += lines
+                lines.clear()
+                lock.release()
+
+                if till_eof and len(result[-1]) != 0:
+                    continue
+
+                return result
+
+            if not till_eof and not wait_new:
+                return None
+            time.sleep(0.001)
+