Added the protocol specification.

[software/pymin.git] / pymin / eventloop.py

diff --git a/pymin/eventloop.py b/pymin/eventloop.py
index 06922a72fe9290bcfb5133700e49ae6187d0dc3c..86b89324eae7cfeff644cf1623d02e827185325a 100644 (file)
--- a/pymin/eventloop.py
+++ b/pymin/eventloop.py
@@ -7,6 +7,8 @@ Please see EventLoop class documentation for more info.
 """
 
 import select
 """
 
 import select

+import errno
+import signal

 from select import POLLIN, POLLPRI, POLLERR
 
 __ALL__ = ('EventLoop', 'LoopInterruptedError')
 from select import POLLIN, POLLPRI, POLLERR
 
 __ALL__ = ('EventLoop', 'LoopInterruptedError')


@@ -35,8 +37,16 @@ class LoopInterruptedError(RuntimeError):
         r"str(obj) -> String representation."
         return 'Loop interrupted: %s' % self.select_error
 
         r"str(obj) -> String representation."
         return 'Loop interrupted: %s' % self.select_error
 

+# Flag to know if a timer was expired
+timeout = False
+
+# Alarm Signal handler
+def alarm_handler(signum, stack_frame):
+    global timeout
+    timeout = True
+

 class EventLoop:
 class EventLoop:

-    r"""EventLoop(file[, handler]) -> EventLoop instance
+    r"""EventLoop(file[, timer[, handler[, timer_handler]]]) -> EventLoop.

 
     This class implements a simple event loop based on select module.
     It "listens" to activity a single 'file' object (a file, a pipe,
 
     This class implements a simple event loop based on select module.
     It "listens" to activity a single 'file' object (a file, a pipe,


@@ -44,9 +54,12 @@ class EventLoop:
     function (or the handle() method if you prefer subclassing) every
     time the file is ready for reading (or has an error).
 
     function (or the handle() method if you prefer subclassing) every
     time the file is ready for reading (or has an error).
 

+    If a 'timer' is supplied, then the timer_handler() function object
+    (or the handle_timer() method) is called every 'timer' seconds.
+

     This is a really simple example of usage using a hanlder callable:
 
     This is a really simple example of usage using a hanlder callable:
 

-    >>> import os 
+    >>> import os

     >>> def handle(event_loop):
             data = os.read(event_loop.fileno, 100)
             os.write(1, 'Received message: %r\n' % data)
     >>> def handle(event_loop):
             data = os.read(event_loop.fileno, 100)
             os.write(1, 'Received message: %r\n' % data)


@@ -66,14 +79,16 @@ class EventLoop:
     >>>             self.stop()
     >>>         else:
     >>>             os.write(1, 'Received message: %r\n' % data)
     >>>             self.stop()
     >>>         else:
     >>>             os.write(1, 'Received message: %r\n' % data)

-    >>> p = Test(0)
+    >>>     def handle_timer(self):
+    >>>         print time.strftime('%c')
+    >>> p = Test(0, timer=5)

     >>> p.loop()
 
     This example loops until the user enters a single "q", when stop()
     is called and the event loop is exited.
     """
 
     >>> p.loop()
 
     This example loops until the user enters a single "q", when stop()
     is called and the event loop is exited.
     """
 

-    def __init__(self, file, handler=None):
+    def __init__(self, file, handler=None, timer=None, timer_handler=None):

         r"""Initialize the EventLoop object.
 
         See EventLoop class documentation for more info.
         r"""Initialize the EventLoop object.
 
         See EventLoop class documentation for more info.


@@ -81,7 +96,9 @@ class EventLoop:
         self.poll = select.poll()
         self._stop = False
         self.__register(file)
         self.poll = select.poll()
         self._stop = False
         self.__register(file)

+        self.timer = timer

         self.handler = handler
         self.handler = handler

+        self.timer_handler = timer_handler

 
     def __register(self, file):
         r"__register(file) -> None :: Register a new file for polling."
 
     def __register(self, file):
         r"__register(file) -> None :: Register a new file for polling."


@@ -125,26 +142,45 @@ class EventLoop:
         Wait for events and handle then when they arrive. If once is True,
         then only 1 event is processed and then this method returns.
         """
         Wait for events and handle then when they arrive. If once is True,
         then only 1 event is processed and then this method returns.
         """

+        # Flag modified by the signal handler
+        global timeout
+        # If we use a timer, we set up the signal
+        if self.timer is not None:
+            signal.signal(signal.SIGALRM, alarm_handler)
+            self.handle_timer()
+            signal.alarm(self.timer)

         while True:
             try:
                 res = self.poll.poll()
             except select.error, e:
         while True:
             try:
                 res = self.poll.poll()
             except select.error, e:

-                raise LoopInterruptedError(e)
-            if self.handler is not None:
-                self.handler(self)
+                # The error is not an interrupt caused by the alarm, then raise
+                if e.args[0] != errno.EINTR or not timeout:
+                    raise LoopInterruptedError(e)
+            # There was a timeout, so execute the timer handler
+            if timeout:
+                timeout = False
+                self.handle_timer()
+                signal.alarm(self.timer)
+            # Not a timeout, execute the regular handler

             else:
                 self.handle()
             else:
                 self.handle()

+            # Look if we have to stop

             if self._stop or once:
                 self._stop = False
                 break
 
     def handle(self):
         r"handle() -> None :: Abstract method to be overriden to handle events."
             if self._stop or once:
                 self._stop = False
                 break
 
     def handle(self):
         r"handle() -> None :: Abstract method to be overriden to handle events."

-        raise NotImplementedError
+        self.handler(self)
+
+    def handle_timer(self):
+        r"handle() -> None :: Abstract method to be overriden to handle events."
+        self.timer_handler(self)

 
 if __name__ == '__main__':
 
     import os
 
 if __name__ == '__main__':
 
     import os

+    import time

 
     def handle(event_loop):
         data = os.read(event_loop.fileno, 100)
 
     def handle(event_loop):
         data = os.read(event_loop.fileno, 100)


@@ -163,8 +199,10 @@ if __name__ == '__main__':
                 self.stop()
             else:
                 os.write(1, 'Received message: %r\n' % data)
                 self.stop()
             else:
                 os.write(1, 'Received message: %r\n' % data)

+        def handle_timer(self):
+            print time.strftime('%c')

 
 

-    p = Test(0)
+    p = Test(0, timer=5)

 
     os.write(1, 'Say a lot of things, then press write just "q" to stop: ')
     p.loop()
 
     os.write(1, 'Say a lot of things, then press write just "q" to stop: ')
     p.loop()