Lock during refresh in order to manage concurrency, fixes #5

squinnondation/hazel.py

@@ -4,7 +4,7 @@ from datetime import datetime
 from random import randint
 from typing import Any, Tuple
 from ipaddress import IPv6Address
-from threading import Thread
+from threading import Thread, RLock
 import curses
 import re
 import socket
@@ -55,6 +55,9 @@ class Squirrel(Hazelnut):
         self.input_index = 0
         self.last_line = -1
 
+        # Lock the refresh function in order to avoid concurrent refresh
+        self.refresh_lock = RLock()
+
         self.history = []
         self.received_messages = dict()
         self.history_pad = curses.newpad(curses.LINES - 2, curses.COLS)
@@ -371,6 +374,8 @@ class Squirrel(Hazelnut):
         """
         Rewrite the history of the messages.
         """
+        self.refresh_lock.acquire()
+
         y, x = self.squinnondation.screen.getmaxyx()
         if curses.is_term_resized(curses.LINES, curses.COLS):
             curses.resizeterm(y, x)
@@ -398,10 +403,14 @@ class Squirrel(Hazelnut):
             y_offset += true_width // (curses.COLS - 1)
         self.history_pad.refresh(0, 0, 0, 0, curses.LINES - 2, curses.COLS)
 
+        self.refresh_lock.release()
+
     def refresh_input(self) -> None:
         """
         Redraw input line. Must not be called while the message is not sent.
         """
+        self.refresh_lock.acquire()
+
         self.input_pad.erase()
         color_id = sum(ord(c) for c in self.nickname) % 6 + 1
         self.input_pad.addstr(0, 0, "<")
@@ -416,6 +425,8 @@ class Squirrel(Hazelnut):
             self.input_pad.addstr(0, self.input_pad.getmaxyx()[1] - 3, "😀")
         self.input_pad.refresh(0, 0, curses.LINES - 1, 0, curses.LINES - 1, curses.COLS - 1)
 
+        self.refresh_lock.release()
+
     def refresh_emoji_pad(self) -> None:
         """
         Display the emoji pad if necessary.
@@ -425,6 +436,8 @@ class Squirrel(Hazelnut):
 
         from emoji import unicode_codes
 
+        self.refresh_lock.acquire()
+
         self.emoji_pad.erase()
 
         if self.emoji_panel_page > 0:
@@ -455,6 +468,8 @@ class Squirrel(Hazelnut):
             self.emoji_pad.refresh(0, 0, curses.LINES - height - 2, curses.COLS - width - 2,
                                    curses.LINES - 2, curses.COLS - 2)
 
+        self.refresh_lock.release()
+
 
 class Worm(Thread):
     """