[401] | 1 |
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| 2 | from util import utf2unicode
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[182] | 3 |
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| 4 | import os
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| 5 | import time
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| 6 |
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| 7 | #----------------------------------------------------------------------------
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| 8 |
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[298] | 9 | ## @package mlx.singleton
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| 10 | #
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| 11 | # Allow a single instance of an application to run.
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| 12 | #
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| 13 | # This module implements the logic needed to detect that an instance of the
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| 14 | # application is already running, and if so, notifying that instance.
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| 15 | #
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| 16 | # On Windows, a mutex is used to ensure that only a single instance is running,
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| 17 | # since a mutex with a certain name can be created by one process only. If the
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| 18 | # current process is the only instance, a named pipe is created and a thread is
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| 19 | # started to listen for messages. Otherwise a message is sent to that pipe,
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| 20 | # which results in calling a callback function.
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| 21 | #
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| 22 | # On Linux a Unix socket is created protected by a lock file, and the messages
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| 23 | # from other instances are received via this socket.
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| 24 | #
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| 25 | # The main window is raised if another instance is started.
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| 26 |
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| 27 | #----------------------------------------------------------------------------
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| 28 |
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[182] | 29 | if os.name=="nt":
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| 30 | import win32event
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| 31 | import win32file
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| 32 | import win32pipe
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| 33 | import win32api
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| 34 | import winerror
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| 35 |
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| 36 | import threading
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| 37 |
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| 38 | class _PipeServer(threading.Thread):
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| 39 | """A server that creates a named pipe, and waits for messages on
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| 40 | that."""
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| 41 |
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| 42 | BUFFER_SIZE = 4096
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| 43 |
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| 44 | def __init__(self, pipeName, raiseCallback):
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| 45 | """Construct the server thread."""
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| 46 | super(_PipeServer, self).__init__()
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| 47 |
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| 48 | self._pipeName = pipeName
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| 49 | self._raiseCallback = raiseCallback
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| 50 | self.daemon = True
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| 51 |
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| 52 | def run(self):
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| 53 | """Perform the operation of the thread."""
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| 54 | try:
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| 55 | while True:
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| 56 | handle = self._createPipe()
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| 57 |
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| 58 | if handle is None:
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| 59 | break
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| 60 |
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| 61 | print "singleton._PipeServer.run: created the pipe"
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| 62 | try:
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| 63 | if win32pipe.ConnectNamedPipe(handle)==0:
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| 64 | print "singleton._PipeServer.run: client connection received"
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| 65 | (code, message) = \
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| 66 | win32file.ReadFile(handle,
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| 67 | _PipeServer.BUFFER_SIZE,
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| 68 | None)
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| 69 |
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| 70 | if code==0:
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| 71 | print "singleton._PipeServer.run: message received from client"
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| 72 | self._raiseCallback()
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| 73 | else:
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| 74 | print "singleton._PipeServer.run: failed to read from the pipe"
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| 75 | except Exception, e:
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[401] | 76 | print "singleton._PipeServer.run: exception:",
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| 77 | print utf2unicode(str(e))
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[182] | 78 | finally:
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| 79 | win32pipe.DisconnectNamedPipe(handle)
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| 80 | win32file.CloseHandle(handle)
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| 81 | except Exception, e:
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[401] | 82 | print "singleton._PipeServer.run: fatal exception:",
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| 83 | print utf2unicode(str(e))
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[182] | 84 |
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| 85 | def _createPipe(self):
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| 86 | """Create the pipe."""
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| 87 | handle = win32pipe.CreateNamedPipe(self._pipeName,
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| 88 | win32pipe.PIPE_ACCESS_INBOUND,
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| 89 | win32pipe.PIPE_TYPE_BYTE |
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| 90 | win32pipe.PIPE_READMODE_BYTE |
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| 91 | win32pipe.PIPE_WAIT,
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| 92 | win32pipe.PIPE_UNLIMITED_INSTANCES,
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| 93 | _PipeServer.BUFFER_SIZE,
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| 94 | _PipeServer.BUFFER_SIZE,
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| 95 | 1000,
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| 96 | None)
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| 97 | if handle==win32file.INVALID_HANDLE_VALUE:
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| 98 | print "singleton._PipeServer.run: could not create the handle"
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| 99 | return None
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| 100 | else:
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| 101 | return handle
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| 102 |
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| 103 | class SingleInstance(object):
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| 104 | """Creating an instance of this object checks if only one instance of
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| 105 | the process runs."""
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| 106 | def __init__(self, baseName, raiseCallback):
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| 107 | """Construct the single instance object.
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| 108 |
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| 109 | raiseCallback is a function that will be called, if another
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| 110 | instance of the program is started."""
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| 111 | self._name = baseName + "_" + win32api.GetUserName()
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| 112 | self._mutex = win32event.CreateMutex(None, False, self._name)
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| 113 | self._isSingle = win32api.GetLastError() != \
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| 114 | winerror.ERROR_ALREADY_EXISTS
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| 115 | if self._isSingle:
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| 116 | self._startPipeServer(raiseCallback)
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| 117 | else:
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| 118 | self._notifySingleton()
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| 119 |
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[247] | 120 | def close(self):
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| 121 | """Close the instance by closing the mutex."""
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| 122 | if self._mutex:
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| 123 | win32api.CloseHandle(self._mutex)
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| 124 | self._mutex = None
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| 125 |
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[182] | 126 | def _getPipeName(self):
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| 127 | """Get the name of the pipe to be used for communication."""
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| 128 | return r'\\.\pipe\\' + self._name
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| 129 |
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| 130 | def _startPipeServer(self, raiseCallback):
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| 131 | """Start the pipe server"""
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| 132 | pipeServer = _PipeServer(self._getPipeName(),
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| 133 | raiseCallback)
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| 134 | pipeServer.start()
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| 135 |
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| 136 | def _notifySingleton(self):
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| 137 | """Notify the already running instance of the program of our
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| 138 | presence."""
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| 139 | pipeName = self._getPipeName()
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| 140 | for i in range(0, 3):
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| 141 | try:
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| 142 | f = open(pipeName, "wb")
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| 143 | f.write("hello")
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| 144 | f.close()
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| 145 | return
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| 146 | except Exception, e:
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[401] | 147 | print "SingleInstance._notifySingleton: failed:",
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| 148 | print utf2unicode(str(e))
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[182] | 149 | time.sleep(0.5)
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| 150 |
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| 151 | def __nonzero__(self):
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| 152 | """Return a boolean representation of the object.
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| 153 |
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| 154 | It is True, if this is the single instance of the program."""
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| 155 | return self._isSingle
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| 156 |
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| 157 | def __del__(self):
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| 158 | """Destroy the object."""
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[247] | 159 | self.close()
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| 160 |
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[182] | 161 | #----------------------------------------------------------------------------
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| 162 |
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| 163 | else: # os.name=="nt"
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| 164 | import fcntl
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| 165 | import socket
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| 166 | import tempfile
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| 167 | import threading
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| 168 |
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| 169 | class _SocketServer(threading.Thread):
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| 170 | """Server thread to handle the Unix socket through which we are
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| 171 | notified of other instances starting."""
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| 172 | def __init__(self, socketName, raiseCallback):
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| 173 | """Construct the server."""
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| 174 | super(_SocketServer, self).__init__()
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| 175 |
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| 176 | self._socketName = socketName
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| 177 | self._raiseCallback = raiseCallback
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| 178 |
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| 179 | self.daemon = True
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| 180 |
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| 181 |
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| 182 | def run(self):
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| 183 | """Perform the thread's operation."""
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| 184 | try:
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| 185 | try:
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| 186 | os.remove(self._socketName)
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| 187 | except:
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| 188 | pass
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| 189 |
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| 190 | s = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
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| 191 | s.bind(self._socketName)
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| 192 |
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| 193 | while True:
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| 194 | s.recv(64)
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| 195 | self._raiseCallback()
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| 196 | except Exception, e:
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[401] | 197 | print "singleton._SocketServer.run: fatal exception:",
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| 198 | print utf2unicode(str(e))
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[182] | 199 |
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| 200 | class SingleInstance(object):
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| 201 | """Creating an instance of this object checks if only one instance of
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| 202 | the process runs."""
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| 203 | def __init__(self, baseName, raiseCallback):
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| 204 | """Construct the single instance object.
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| 205 |
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| 206 | raiseCallback is a function that will be called, if another
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| 207 | instance of the program is started."""
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| 208 | baseName = baseName + "_" + os.environ["LOGNAME"]
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| 209 |
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| 210 | tempDir = tempfile.gettempdir()
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| 211 | self._lockName = os.path.join(tempDir, baseName + ".lock")
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| 212 | self._socketName = os.path.join(tempDir, baseName + ".sock")
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| 213 |
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| 214 | self._lockFile = open(self._lockName, "w")
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| 215 |
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| 216 | self._isSingle = False
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| 217 | try:
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| 218 | fcntl.lockf(self._lockFile, fcntl.LOCK_EX | fcntl.LOCK_NB)
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| 219 | self._isSingle = True
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| 220 | except Exception, e:
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| 221 | self._lockFile.close()
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| 222 | self._lockFile = None
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| 223 | pass
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| 224 |
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| 225 | if self._isSingle:
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| 226 | self._startSocketServer(raiseCallback)
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| 227 | else:
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| 228 | self._notifySingleton()
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| 229 |
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[247] | 230 | def close(self):
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| 231 | """Close the instance by closing the mutex."""
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| 232 | if self._isSingle:
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| 233 | if self._lockFile:
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| 234 | self._lockFile.close()
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| 235 | self._lockFile = None
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| 236 | try:
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| 237 | os.remove(self._lockName)
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| 238 | except:
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| 239 | pass
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| 240 | try:
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| 241 | os.remove(self._socketName)
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| 242 | except:
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| 243 | pass
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| 244 |
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| 245 |
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[182] | 246 | def _startSocketServer(self, raiseCallback):
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| 247 | """Start the pipe server"""
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| 248 | pipeServer = _SocketServer(self._socketName, raiseCallback)
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| 249 | pipeServer.start()
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| 250 |
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| 251 | def _notifySingleton(self):
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| 252 | """Notify the already running instance of the program of our
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| 253 | presence."""
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| 254 | s = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
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| 255 | for i in range(0, 3):
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| 256 | try:
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| 257 | s.connect(self._socketName)
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| 258 | s.send("hello")
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| 259 | s.close()
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| 260 | return
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| 261 | except Exception, e:
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[401] | 262 | print "singleton.SingleInstance._notifySingleton: failed:",
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| 263 | print utf2unicode(str(e))
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[182] | 264 | time.sleep(0.5)
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| 265 |
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| 266 | def __nonzero__(self):
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| 267 | """Return a boolean representation of the object.
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| 268 |
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| 269 | It is True, if this is the single instance of the program."""
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| 270 | return self._isSingle
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| 271 |
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| 272 | def __del__(self):
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| 273 | """Destroy the object."""
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[247] | 274 | self.close()
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[182] | 275 |
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| 276 | #----------------------------------------------------------------------------
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| 277 | #----------------------------------------------------------------------------
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| 278 |
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| 279 | # MAVA Logger X-specific stuff
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| 280 |
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| 281 | #----------------------------------------------------------------------------
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| 282 |
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| 283 | # The callback to use
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| 284 | raiseCallback = None
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| 285 |
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| 286 | #----------------------------------------------------------------------------
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| 287 |
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| 288 | def raiseCallbackWrapper():
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| 289 | """The actual function to be used as the callback.
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| 290 |
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| 291 | It checks if raiseCallback is None, and if not, it calls that."""
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| 292 | callback = raiseCallback
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| 293 | if callback is not None:
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| 294 | callback()
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| 295 |
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| 296 | #----------------------------------------------------------------------------
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| 297 | #----------------------------------------------------------------------------
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| 298 |
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| 299 | if __name__=="__main__":
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| 300 | def raiseCallback():
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| 301 | print "Raise the window!"
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| 302 |
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| 303 | instance = SingleInstance("mlx", raiseCallback)
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| 304 | if instance:
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| 305 | print "The first instance"
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| 306 | time.sleep(10)
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| 307 | else:
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| 308 | print "The program is already running."
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| 309 |
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