On Thu, Aug 26, 2010 at 11:47 AM, Sergey Magafurov <smagafu...@naumen.ru> wrote:
> How to rewrite this regular function with Deferred-style?
> Conditions:
> 1. 'cache.open' and 'item.read' become deffered
> 2. 'item.obsolete()' and 'renew(data)' are not deferred
I would probably write it something like this:
def getCachedResult(cache, key):
def _gotResult(item):
try:
if item.obsolete():
return None
d = item.read()
d.addCallback(lambda data: renew(data))
except:
item.release()
raise
d.addBoth(lambda ign: item.release())
return d
def _ebNotFound(f):
f.trap(NotFound)
return None
return cache.open(key).addCallbacks(_gotResult, _ebNotFound)
Note: code is untested
--
mithrandi, i Ainil en-Balandor, a faer Ambar
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