Do not need to specify whether an event source is EDGE or LEVEL triggered

npryce · npryce · commit 5a08f26691b2 · 2013-01-24T10:43:55.000Z
when adding it to the Selector.  The Selector looks for an attribute
__trigger__ on the event source.  If not found, assumes LEVEL.  Can be
overridden if required by explicitly setting the trigger when adding
the event source to the Selector.
diff --git a/examples/epoll-button-blink b/examples/epoll-button-blink
@@ -4,7 +4,7 @@ import sys
 import os
 from contextlib import closing
 from quick2wire.gpio import GPIOPin, Both, In, Out, exported
-from quick2wire.selector import Selector, INPUT, EDGE, Timer
+from quick2wire.selector import Selector, Timer
 
 blink_rate=2.0
 
@@ -13,8 +13,8 @@ with closing(Selector()) as selector, \
      exported(GPIOPin(0, direction=In, interrupt=Both)) as button_pin, \
      exported(GPIOPin(1, direction=Out)) as led_pin:
     
-    selector.add(button_pin, INPUT, trigger=EDGE)
-    selector.add(timer, INPUT)
+    selector.add(button_pin)
+    selector.add(timer)
     
     print("ready")
     
diff --git a/quick2wire/gpio.py b/quick2wire/gpio.py
@@ -6,6 +6,7 @@
 import subprocess
 from contextlib import contextmanager
 from quick2wire.board_revision import revision
+from quick2wire.selector import EDGE
 
 # Maps header pin numbers to SoC GPIO numbers
 # See http://elinux.org/RPi_Low-level_peripherals
@@ -94,6 +95,8 @@ class _IOPin(object):
     PullDown = "pulldown"
     PullUp = "pullup"
     
+    __trigger__ = EDGE
+    
     def __init__(self, user_pin_number, soc_pin_number, direction=None, interrupt=None, pull=None):
         """Creates a pin
         
diff --git a/quick2wire/selector.py b/quick2wire/selector.py
@@ -23,7 +23,6 @@ def __init__(self, size_hint=-1):
         """Initialises a Selector.
         
         Arguments:
-        
         size_hint -- A hint of the number of event sources that will
                      be added to the Selector, or -1 for the default.
                      Used to optimize internal data structures, it
@@ -39,11 +38,10 @@ def fileno(self):
         """Returns the Selector's file descriptor."""
         return self._epoll.fileno()
     
-    def add(self, source, eventmask=INPUT|ERROR, trigger=LEVEL, identifier=None):
+    def add(self, source, eventmask=INPUT|ERROR, trigger=None, identifier=None):
         """Adds an event source to the Selector.
         
         Arguments:
-        
         source     -- the event source to add.  Must provide a fileno() 
                       method that returns its file descriptor.
                       
@@ -66,6 +64,8 @@ def add(self, source, eventmask=INPUT|ERROR, trigger=LEVEL, identifier=None):
                       source itself.
         """
         fileno = source.fileno()
+        trigger = trigger if trigger is not None else getattr(source, "__trigger__", LEVEL)
+        
         self._sources[fileno] = identifier if identifier is not None else source
         self._epoll.register(fileno, eventmask|(select.EPOLLET*trigger))
     
@@ -94,7 +94,6 @@ def wait(self, timeout=-1):
         timeout, the `ready` property is `None`.
         
         Arguments: 
-        
         timeout -- maximum time to wait for an event. Specified in
                    seconds (can be less than one). Default is no
                    timeout: wait forever for an event.
