Reworked read_line timeouts to be a bit more efficient.

pyad2usb/devices.py

@@ -205,12 +205,21 @@ class USBDevice(Device):
         """
         Reads a line from the device.
         """
-        start_time = time.time()
+        def timeout_event():
+            timeout_event.reading = False
+
+        timeout_event.reading = True
+
         got_line = False
         ret = None
 
+        timer = None
+        if timeout > 0:
+            timer = threading.Timer(timeout, timeout_event)
+            timer.start()
+
         try:
-            while self._running:
+            while timeout_event.reading:
                 buf = self._device.read_data(1)
 
                 if buf != '':
@@ -228,10 +237,7 @@ class USBDevice(Device):
                         else:
                             self._buffer = self._buffer[:-1]
 
-                if timeout > 0 and time.time() - start_time > timeout:
-                    raise util.TimeoutError('Timeout while waiting for line terminator.')
-
-                time.sleep(0.1)
+                time.sleep(0.001)
 
         except (usb.core.USBError, FtdiError), err:
             raise util.CommError('Error reading from AD2USB device: {0}'.format(str(err)))
@@ -242,6 +248,9 @@ class USBDevice(Device):
 
                 self.on_read(ret)
 
+        if timer:
+            timer.cancel()
+
         return ret
 
 
@@ -380,12 +389,22 @@ class SerialDevice(Device):
         """
         Reads a line from the device.
         """
-        start_time = time.time()
+
+        def timeout_event():
+            timeout_event.reading = False
+
+        timeout_event.reading = True
+
         got_line = False
         ret = None
 
+        timer = None
+        if timeout > 0:
+            timer = threading.Timer(timeout, timeout_event)
+            timer.start()
+
         try:
-            while self._running:
+            while timeout_event.reading:
                 buf = self._device.read(1)
 
                 if buf != '' and buf != "\xff":     # AD2SERIAL specifically apparently sends down \xFF on boot.
@@ -403,8 +422,7 @@ class SerialDevice(Device):
                         else:
                             self._buffer = self._buffer[:-1]
 
-                if timeout > 0 and time.time() - start_time > timeout:
-                    raise util.TimeoutError('Timeout while waiting for line terminator.')
+                time.sleep(0.001)
 
         except (OSError, serial.SerialException), err:
             raise util.CommError('Error reading from AD2SERIAL device: {0}'.format(str(err)))
@@ -415,6 +433,9 @@ class SerialDevice(Device):
 
                 self.on_read(ret)
 
+        if timer:
+            timer.cancel()
+
         return ret
 
 class SocketDevice(Device):
@@ -527,12 +548,21 @@ class SocketDevice(Device):
         """
         Reads a line from the device.
         """
-        start_time = time.time()
+        def timeout_event():
+            timeout_event.reading = False
+
+        timeout_event.reading = True
+
         got_line = False
         ret = None
 
+        timer = None
+        if timeout > 0:
+            timer = threading.Timer(timeout, timeout_event)
+            timer.start()
+
         try:
-            while self._running:
+            while timeout_event.reading:
                 buf = self._device.recv(1)
 
                 if buf != '':
@@ -550,8 +580,7 @@ class SocketDevice(Device):
                         else:
                             self._buffer = self._buffer[:-1]
 
-                if timeout > 0 and time.time() - start_time > timeout:
-                    raise util.TimeoutError('Timeout while waiting for line terminator.')
+                time.sleep(0.001)
 
         except socket.error, err:
             raise util.CommError('Error reading from Socket device: {0}'.format(str(err)))
@@ -562,4 +591,7 @@ class SocketDevice(Device):
 
                 self.on_read(ret)
 
+        if timer:
+            timer.cancel()
+
         return ret

test.py

@@ -222,18 +222,28 @@ def test_socket():
     a2u.close()
 
 def test_no_read_thread():
-    a2u = pyad2usb.ad2usb.Overseer.create()
+    #a2u = pyad2usb.ad2usb.Overseer.create()
 
-    a2u.on_open += handle_open
-    a2u.on_close += handle_close
-    a2u.on_read += handle_read
-    a2u.on_write += handle_write
 
-    a2u.open(no_reader_thread=True)
+    #a2u.on_open += handle_open
+    #a2u.on_close += handle_close
+    #a2u.on_read += handle_read
+    #a2u.on_write += handle_write
 
-    print 'alive?', a2u._device._read_thread.is_alive()
+    #a2u.open(no_reader_thread=True)
 
-    a2u.close()
+    dev = pyad2usb.ad2usb.devices.SerialDevice(interface='/dev/ttyUSB0')
+    dev.open(no_reader_thread=True)
+
+    #print 'alive?', a2u._device._read_thread.is_alive()
+    while 1:
+        line = dev.read_line(timeout=5)
+        print line
+        line = dev.read_line(timeout=5)
+        print line
+        #time.sleep(0.1)
+
+    dev.close()
 
 def test_serial_grep():
     re =  pyad2usb.devices.SerialDevice.find_all(pattern='VID:PID=9710:7840')
@@ -283,10 +293,10 @@ try:
     #test_socket()
     #upload_socket()
 
-    #test_no_read_thread()
+    test_no_read_thread()
     #test_serial_grep()
 
-    test_double_panel_write()
+    #test_double_panel_write()
 
 except Exception, err:
     traceback.print_exc(err)