Added a thread lock to the TcpClient

This gives multi-threading safety without giving up on speed
(now there's no need for additional sleeps)

network/mtproto_sender.py

@@ -14,22 +14,27 @@ from tl.all_tlobjects import tlobjects
 
 class MtProtoSender:
     """MTProto Mobile Protocol sender (https://core.telegram.org/mtproto/description)"""
-    def __init__(self, transport, session):
+    def __init__(self, transport, session, check_updates_delay=0.1):
+        """If check_updates_delay is None, no updates will be checked.
+           Otherwise, specifies every how often updates should be checked"""
+
         self.transport = transport
         self.session = session
 
         self.need_confirmation = []  # Message IDs that need confirmation
         self.on_update_handlers = []
 
-        # Set up updates thread
-        self.updates_thread = Thread(target=self.updates_thread_method, name='Updates thread')
-        self.updates_thread_running = True
-        self.updates_thread_paused = True
+        # Set up updates thread, if the delay is not None
+        self.check_updates_delay = check_updates_delay
+        if check_updates_delay:
+            self.updates_thread = Thread(target=self.updates_thread_method, name='Updates thread')
+            self.updates_thread_running = True
+            self.updates_thread_paused = True
 
-        self.updates_thread.start()
+            self.updates_thread.start()
 
     def disconnect(self):
-        """Disconnects and **stops all the running threads**"""
+        """Disconnects and **stops all the running threads** if any"""
         self.updates_thread_running = False
         self.transport.cancel_receive()
         self.transport.close()

network/tcp_client.py

@@ -1,6 +1,7 @@
 # Python rough implementation of a C# TCP client
 import socket
 import time
+from threading import Lock
 
 from errors import ReadCancelledError
 from utils import BinaryWriter
@@ -10,8 +11,11 @@ class TcpClient:
     def __init__(self):
         self.connected = False
         self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+
+        # Support for multi-threading advantages and safety
         self.cancelled = False  # Has the read operation been cancelled?
         self.delay = 0.1  # Read delay when there was no data available
+        self.lock = Lock()
 
     def connect(self, ip, port):
         """Connects to the specified IP and port number"""
@@ -27,40 +31,46 @@ class TcpClient:
 
     def write(self, data):
         """Writes (sends) the specified bytes to the connected peer"""
-        self.socket.sendall(data)
+
+        # Ensure that only one thread can send data at once
+        with self.lock:
+            self.socket.sendall(data)
 
     def read(self, buffer_size):
         """Reads (receives) the specified bytes from the connected peer"""
-        self.cancelled = False  # Ensure it is not cancelled at first
 
-        with BinaryWriter() as writer:
-            while writer.written_count < buffer_size and not self.cancelled:
-                try:
-                    # When receiving from the socket, we may not receive all the data at once
-                    # This is why we need to keep checking to make sure that we receive it all
-                    left_count = buffer_size - writer.written_count
-                    partial = self.socket.recv(left_count)
-                    writer.write(partial)
+        # Ensure that only one thread can receive data at once
+        with self.lock:
+            # Ensure it is not cancelled at first, so we can enter the loop
+            self.cancelled = False
 
-                except BlockingIOError:
-                    # There was no data available for us to read. Sleep a bit
-                    time.sleep(self.delay)
+            with BinaryWriter() as writer:
+                while writer.written_count < buffer_size and not self.cancelled:
+                    try:
+                        # When receiving from the socket, we may not receive all the data at once
+                        # This is why we need to keep checking to make sure that we receive it all
+                        left_count = buffer_size - writer.written_count
+                        partial = self.socket.recv(left_count)
+                        writer.write(partial)
 
-            # If the operation was cancelled *but* data was read,
-            # this will result on data loss so raise an exception
-            # TODO this could be solved by using an internal FIFO buffer (first in, first out)
-            if self.cancelled:
-                if writer.written_count == 0:
-                    raise ReadCancelledError()
-                else:
-                    raise NotImplementedError('The read operation was cancelled when some data '
-                                              'was already read. This has not yet implemented '
-                                              'an internal buffer, so cannot continue.')
+                    except BlockingIOError:
+                        # There was no data available for us to read. Sleep a bit
+                        time.sleep(self.delay)
 
-            return writer.get_bytes()
+                # If the operation was cancelled *but* data was read,
+                # this will result on data loss so raise an exception
+                # TODO this could be solved by using an internal FIFO buffer (first in, first out)
+                if self.cancelled:
+                    if writer.written_count == 0:
+                        raise ReadCancelledError()
+                    else:
+                        raise NotImplementedError('The read operation was cancelled when some data '
+                                                  'was already read. This has not yet implemented '
+                                                  'an internal buffer, so cannot continue.')
+
+                # If everything went fine, return the read bytes
+                return writer.get_bytes()
 
     def cancel_read(self):
-        """Cancels the read operation if it was blocking and stops
-           the current thread until it's cancelled"""
+        """Cancels the read operation raising a ReadCancelledError"""
         self.cancelled = True
-        time.sleep(self.delay)

network/tcp_transport.py

@@ -60,8 +60,8 @@ class TcpTransport:
             self.tcp_client.close()
 
     def cancel_receive(self):
-        """Cancels (stops) trying to receive from the remote peer and
-           stops the current thread until it's cancelled"""
+        """Cancels (stops) trying to receive from the
+        remote peer and raises a ReadCancelledError"""
         self.tcp_client.cancel_read()
 
     def get_client_delay(self):