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