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#!/usr/bin/env python
#
# A port of the semaphore example from Qt.
import sys
# Check if thread support was enabled.
try:
from qt import QThread
except:
print "Thread support not enabled"
sys.exit(1)
from qt import *
# The semaphore instances.
yellowSem = None
greenSem = None
class YellowThread(QThread):
def __init__(self,o):
QThread.__init__(self)
self.receiver = o
self.stopped = 0
self.mutex = QMutex()
def run(self):
global yellowSem, greenSem
for i in range(20):
yellowSem += 1
event = QCustomEvent(12345)
event.setData(QString("Yellow!"))
QThread.postEvent(self.receiver,event)
self.msleep(200);
greenSem -= 1
self.mutex.lock()
if self.stopped:
self.stopped = 0
self.mutex.unlock()
break
self.mutex.unlock()
yellowSem += 1
event = QCustomEvent(12346)
event.setData(QString("Yellow!"))
QThread.postEvent(self.receiver,event)
greenSem -= 1
def stop(self):
self.mutex.lock()
self.stopped = 1
self.mutex.unlock()
class GreenThread(QThread):
def __init__(self,o):
QThread.__init__(self)
self.receiver = o
self.stopped = 0
self.mutex = QMutex()
def run(self):
global yellowSem, greenSem
for i in range(20):
greenSem += 1
event = QCustomEvent(12345)
event.setData(QString("Green!"))
QThread.postEvent(self.receiver,event)
self.msleep(200)
yellowSem -= 1
self.mutex.lock()
if self.stopped:
self.stopped = 0
self.mutex.unlock()
break
self.mutex.unlock()
greenSem += 1
event = QCustomEvent(12346)
event.setData(QString("Green!"))
QThread.postEvent(self.receiver,event)
self.msleep(10)
yellowSem -= 1
def stop(self):
self.mutex.lock()
self.stopped = 1
self.mutex.unlock()
class SemaphoreExample(QWidget):
def __init__(self):
QWidget.__init__(self)
self.yellowThread = YellowThread(self)
self.greenThread = GreenThread(self)
global yellowSem, greenSem
yellowSem = QSemaphore(1)
greenSem = QSemaphore(1)
self.button = QPushButton("&Ignition!",self)
self.connect(self.button,SIGNAL("clicked()"),self.startExample)
self.mlineedit = QMultiLineEdit(self)
self.label = QLabel(self)
vbox = QVBoxLayout(self,5)
vbox.addWidget(self.button)
vbox.addWidget(self.mlineedit)
vbox.addWidget(self.label)
def __del__(self):
stopYellow = self.yellowThread.running()
stopGreen = self.greenThread.running()
if stopYellow:
self.yellowThread.stop()
if self.greenThread.running():
self.greenThread.stop()
if stopYellow:
self.yellowThread.wait()
if stopGreen:
self.greenThread.wait()
global yellowSem, greenSem
yellowSem = None
greenSem = None
def startExample(self):
if self.yellowThread.running() or self.greenThread.running():
QMessageBox.information(self,"Sorry",
"The threads have not completed yet, and must finish before "
"they can be started again.")
return
self.mlineedit.clear()
global yellowSem
while yellowSem.available() < yellowSem.total():
yellowSem -= 1
yellowSem += 1
self.yellowThread.start()
self.greenThread.start()
def customEvent(self,event):
if event.type() == 12345:
s = event.data()
self.mlineedit.append(s)
if s.latin1() == "Green!":
self.label.setBackgroundColor(Qt.green)
else:
self.label.setBackgroundColor(Qt.yellow)
self.label.setText(s)
del s
elif event.type() == 12346:
s = event.data()
QMessageBox.information(self,s.latin1() + " - Finished",
"The thread creating the \"" + s.latin1() +
"\" events has finished.")
del s
else:
print "Unknown custom event type:", event.type()
app = QApplication(sys.argv)
se = SemaphoreExample()
app.setMainWidget(se)
se.show()
sys.exit(app.exec_loop())
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