gistfile1.py

def inlineCallbacks(f):
    from functools import wraps
    @wraps(f)
    def _(*args, **kwargs):
        gen = f(*args, **kwargs)
        stop_running = [False]
        def cancelled(df_):
            assert df_ is df
            stop_running[0] = True
            if currently_waiting_on:
                currently_waiting_on[0].cancel()
        df = defer.Deferred(cancelled)
        currently_waiting_on = []
        def it(cur):
            while True:
                try:
                    if isinstance(cur, failure.Failure):
                        res = cur.throwExceptionIntoGenerator(gen) # external code is run here
                    else:
                        res = gen.send(cur) # external code is run here
                    if stop_running[0]:
                        return
                except StopIteration:
                    df.callback(None)
                except defer._DefGen_Return as e:
                    # XXX should make sure direct child threw
                    df.callback(e.value)
                except:
                    df.errback()
                else:
                    if isinstance(res, defer.Deferred):
                        called, res2 = deferred_has_been_called(res)
                        if called:
                            cur = res2
                            continue
                        else:
                            currently_waiting_on[:] = [res]
                            def gotResult(res2):
                                assert currently_waiting_on[0] is res
                                currently_waiting_on[:] = []
                                if stop_running[0]:
                                    return
                                it(res2)
                            res.addBoth(gotResult) # external code is run between this and gotResult
                    else:
                        cur = res
                        continue
                break
        it(None)
        return df
    return _