try to fix ui freeze when filtering huge files

logFileModel.py

@@ -1,5 +1,6 @@
 import math
 import threading
+import time
 from typing import List
 from line import Line
 import os
@@ -7,11 +8,11 @@ from settings import Settings
 
 
 class LogFileModel:
-    _lock = threading.RLock()
 
     def __init__(self, file:str, settings: Settings):
         self.settings = settings
         self._file = os.path.realpath(file)
+        self._lock = threading.RLock()
 
     def get_file(self):
         return self._file
@@ -36,11 +37,12 @@ class LogFileModel:
         #print("data(%s, %s, %s)" % (byte_offset, scroll_lines, lines))
         lines_before_offset: List[Line] = []
         lines_after_offset: List[Line] = []
-        result: List[Line] = []
         lines_to_find = lines  + abs(scroll_lines)
         lines_to_return = math.ceil(lines)
 
+        #start = time.time()
         with self._lock:
+            #print("data lock acquision %.4f" % (time.time() -start))
             # TODO handle lines longer than 4096 bytes
             # TODO abort file open after a few secons: https://docs.python.org/3/library/signal.html#example
             with open(self._file, 'rb') as f: