class ProcessHandler(QObject):
commandReceived = pyqtSignal(str)
commandSent = pyqtSignal(str)
processFinished = pyqtSignal()
processError = pyqtSignal(str)
def __init__(self, executable, parent=None):
QObject.__init__(self, parent)
self.executable = executable
def run(self):
self.process = QProcess()
self.process.readyReadStandardOutput.connect(self.handleInput)
self.process.setReadChannel(QProcess.StandardOutput)
self.process.closeReadChannel(QProcess.StandardError)
self.process.finished.connect(self.processFinished)
self.pendingInput = QByteArray()
self.in_message = False
self.inputExpected = 0
self.pendingOutput = QByteArray()
self.process.start(self.executable)
# On Qt 5.6 and later, we can use the errorOccurred signal instead.
if not self.process.waitForStarted(-1):
self.processError.emit("The application quit unexpectedly.")
def quit(self):
print("Terminating %i" % self.process.processId())
self.process.closeReadChannel(QProcess.StandardOutput)
self.process.closeReadChannel(QProcess.StandardError)
self.process.closeWriteChannel()
self.process.terminate()
self.process.waitForFinished()
self.thread().quit()
def handleInput(self):
self.pendingInput += self.process.readAllStandardOutput()
try:
while self.pendingInput.size() > 0:
if not self.in_message:
space = self.pendingInput.indexOf(b" ")
if space == -1:
return
# Specify UTF-8 instead of falling back on something implicit.
self.inputExpected = int(
str(self.pendingInput.left(space), "utf8"))
# Examine the rest of the input.
self.pendingInput = self.pendingInput.mid(space + 1)
self.in_message = True
# Try to read the rest of the message.
if len(self.pendingInput) >= self.inputExpected:
command = self.pendingInput.left(self.inputExpected)
self.pendingInput = self.pendingInput.mid(
self.inputExpected)
self.in_message = False
self.inputExpected = 0
self.commandReceived.emit(str(command, "utf8"))
elif self.process.bytesAvailable() > 0:
self.pendingInput += self.process.readAllStandardOutput()
else:
return
except ValueError:
self.processError.emit(str(self.pendingInput, "utf8"))
def handleOutput(self, message):
# Write the length of the message and the message itself.
message = "%i %s" % (len(message), message)
self.pendingOutput += QByteArray(bytes(message, "utf8"))
while self.pendingOutput.size() > 0:
written = self.process.write(self.pendingOutput)
if written == -1:
self.processError.emit("Failed to write to application.")
return
# Handle the rest of the output.
self.pendingOutput = self.pendingOutput.mid(written)
self.commandSent.emit(message)
