def makeTSServerObjects(tsServer, wallClock, timelineSelector, tickRate,
startTickValue):
"""\
create a clock with tick rate, and correlated with wall clock to be paused at the intended start value.
create a time line source, that uses the wall clock and timeline clock for creating time stamps to
be sent by the TS server on demand of the harness (by calling sendTSMessage).
attach that time line to the TS server. No messages are sent over TS protocol until
client(s) are connected, and only then when sendTSMessage() is called by the harness
"""
syncClock = CorrelatedClock(parentClock=wallClock, tickRate=tickRate)
syncClock.speed = 0
syncClock.correlation = (wallClock.ticks, startTickValue)
pauseSyncTimelineClock(syncClock)
# Once added to the TS server, the timeline is available for clients to request via the server
# for TS messages from this type of timeline, if it exists for the CI stem sent by the TS client.
# normally this CI stem matches a substring of the CII-delivered contentId.
syncTimelineSrc = SimpleClockTimelineSource(
timelineSelector=timelineSelector,
wallClock=wallClock,
clock=syncClock)
tsServer.attachTimelineSource(syncTimelineSrc)
return syncClock
def algorithm(self):
candidateClock = CorrelatedClock(self.clock.getParent(),
tickRate=self.clock.tickRate,
correlation=self.clock.correlation)
while True:
update = False
cumulativeOffset = None
candidate = (yield self.timeoutSecs)
t = self.clock.ticks
currentDispersion = self.clock.dispersionAtTime(t)
if candidate is not None:
candidateClock.correlation = candidate.calcCorrelationFor(
self.clock, self.localMaxFreqErrorPpm)
candidateDispersion = candidateClock.dispersionAtTime(t)
update = candidateDispersion < currentDispersion
if update:
pt = self.clock.toParentTicks(t)
adjustment = candidateClock.fromParentTicks(pt) - t
if cumulativeOffset is None:
cumulativeOffset = 0
else:
cumulativeOffset += adjustment
self.clock.correlation = candidateClock.correlation
self.onClockAdjusted(
self.clock.ticks, adjustment,
1000000000 * currentDispersion,
1000000000 * candidateDispersion,
self.clock.correlation.errorGrowthRate)
else:
pass
# update worst dispersion seen so far
self.worstDispersion = max(self.worstDispersion,
currentDispersion,
candidateDispersion)
co = cumulativeOffset or 0 # convert None to 0
self.log.info(
"Old / New dispersion (millis) is %.5f / %.5f ... offset=%20d new best candidate? %s\n"
% (1000 * currentDispersion, 1000 * candidateDispersion,
co, str(update)))
else:
self.log.info("Timeout. Dispersion (millis) is %.5f\n" %
(1000 * currentDispersion, ))
# retry more quickly if we didn't get an improved candidate
if update:
time.sleep(self.repeatSecs)
else:
time.sleep(self.timeoutSecs)
def test_changeCorrelation(self):
mockTime = self.mockTime
mockTime.timeNow = 5020.8
b = SysClock()
c = CorrelatedClock(b, 1000, correlation=(0,300))
self.assertAlmostEqual(c.ticks, 5020.8*1000 + 300, places=5)
c.correlation = (50000,320)
self.assertEqual(c.correlation, (50000,320))
self.assertAlmostEqual(c.ticks, (int(5020.8*1000000) - 50000) / 1000 + 320, places=5)
def test_changeCorrelation(self):
mockTime = self.mockTime
b = self.newSysClock()
mockTime.timeNow = 5020.8
c = CorrelatedClock(b, 1000, correlation=Correlation(0, 300))
self.assertAlmostEqual(c.ticks, 5020.8 * 1000 + 300, places=5)
c.correlation = Correlation(50000, 320)
self.assertEqual(c.correlation, Correlation(50000, 320))
self.assertAlmostEqual(c.ticks,
(int(5020.8 * 1000000) - 50000) / 1000 + 320,
places=5)
def test_changeCorrelationNotifies(self):
"""Check a change to the correlation propagates notifications to dependents of this clock"""
b = self.newSysClock()
c = CorrelatedClock(b, 1000, correlation=Correlation(0, 300))
cc = CorrelatedClock(c, 50)
d1 = MockDependent()
d2 = MockDependent()
d3 = MockDependent()
b.bind(d1)
c.bind(d2)
cc.bind(d3)
c.correlation = Correlation(50, 20)
d1.assertNotNotified()
d2.assertNotificationsEqual([c])
d3.assertNotificationsEqual([cc])
def test_changeCorrelationNotifies(self):
"""Check a change to the correlation propagates notifications to dependents of this clock"""
b = SysClock()
c = CorrelatedClock(b, 1000, correlation=(0,300))
cc = CorrelatedClock(c, 50)
d1 = MockDependent()
d2 = MockDependent()
d3 = MockDependent()
b.bind(d1)
c.bind(d2)
cc.bind(d3)
c.correlation = (50,20)
d1.assertNotNotified()
d2.assertNotificationsEqual([c])
d3.assertNotificationsEqual([cc])
