process.py

wxPython的基本示例程序

        try:
            self._hProcess, self._hThread, self._processId, self._threadId\
                = _SaferCreateProcess(
                    None,           # app name
                    cmd,            # command line 
                    None,           # process security attributes 
                    None,           # primary thread security attributes 
                    0,              # handles are inherited 
                    self._flags,    # creation flags 
                    self._env,      # environment
                    self._cwd,      # current working directory
                    si)             # STARTUPINFO pointer 
            win32api.CloseHandle(self._hThread)
        except win32api.error, ex:
            raise ProcessError(msg="Error creating process for '%s': %s"\
                                   % (cmd, ex.args[2]),
                               errno=ex.args[0])

    def wait(self, timeout=None): 
        """Wait for the started process to complete.
        
        "timeout" (on Windows) is a floating point number of seconds after
            which to timeout.  Default is win32event.INFINITE.
        "timeout" (on Unix) is akin to the os.waitpid() "options" argument
            (os.WNOHANG may be used to return immediately if the process has
            not exited). Default is 0, i.e. wait forever.

        If the wait time's out it will raise a ProcessError. Otherwise it
        will return the child's exit value (on Windows) or the child's exit
        status excoded as per os.waitpid() (on Linux):
            "a 16-bit number, whose low byte is the signal number that killed
            the process, and whose high byte is the exit status (if the
            signal number is zero); the high bit of the low byte is set if a
            core file was produced."
        In the latter case, use the os.W*() methods to interpret the return
        value.
        """
        # XXX Or should returning the exit value be move out to another
        #     function as on Win32 process control? If so, then should
        #     perhaps not make WaitForSingleObject semantic transformation.
        if sys.platform.startswith("win"):
            if timeout is None:
                timeout = win32event.INFINITE
            else:
                timeout = timeout * 1000.0 # Win32 API's timeout is in millisecs

            rc = win32event.WaitForSingleObject(self._hProcess, timeout)
            if rc == win32event.WAIT_FAILED:
                raise ProcessError("'WAIT_FAILED' when waiting for process to "\
                                   "terminate: %r" % self._cmd, rc)
            elif rc == win32event.WAIT_TIMEOUT:
                raise ProcessError("'WAIT_TIMEOUT' when waiting for process to "\
                                   "terminate: %r" % self._cmd, rc)

            retval = win32process.GetExitCodeProcess(self._hProcess)
        else:
            # os.waitpid() will raise:
            #       OSError: [Errno 10] No child processes
            # on subsequent .wait() calls. Change these semantics to have
            # subsequent .wait() calls return the exit status and return
            # immediately without raising an exception.
            # (XXX It would require synchronization code to handle the case
            # of multiple simultaneous .wait() requests, however we can punt
            # on that because it is moot while Linux still has the problem
            # for which _ThreadFixer() exists.)
            if self.__retvalCache is not None:
                retval = self.__retvalCache
            else:
                if timeout is None:
                    timeout = 0
                pid, sts = os.waitpid(self._pid, timeout)
                if pid == self._pid:
                    self.__retvalCache = retval = sts
                else:
                    raise ProcessError("Wait for process timed out.",
                                       self.WAIT_TIMEOUT)
        return retval

    def kill(self, exitCode=0, gracePeriod=1.0, sig=None):
        """Kill process.
        
        "exitCode" [deprecated, not supported] (Windows only) is the
            code the terminated process should exit with.
        "gracePeriod" (Windows only) is a number of seconds the process is
            allowed to shutdown with a WM_CLOSE signal before a hard
            terminate is called.
        "sig" (Unix only) is the signal to use to kill the process. Defaults
            to signal.SIGKILL. See os.kill() for more information.

        Windows:
            Try for an orderly shutdown via WM_CLOSE.  If still running
            after gracePeriod (1 sec. default), terminate.
        """
        if sys.platform.startswith("win"):
            import win32gui
            # Send WM_CLOSE to windows in this process group.
            win32gui.EnumWindows(self._close_, 0)

            # Send Ctrl-Break signal to all processes attached to this
            # console. This is supposed to trigger shutdown handlers in
            # each of the processes.
            try:
                win32api.GenerateConsoleCtrlEvent(CTRL_BREAK_EVENT,
                                                  self._processId)
            except AttributeError:
                log.warn("The win32api module does not have "\
                         "GenerateConsoleCtrlEvent(). This may mean that "\
                         "parts of this process group have NOT been killed.")
            except win32api.error, ex:
                if ex.args[0] not in (6, 87):
                    # Ignore the following:
                    #   api_error: (87, 'GenerateConsoleCtrlEvent', 'The parameter is incorrect.')
                    #   api_error: (6, 'GenerateConsoleCtrlEvent', 'The handle is invalid.')
                    # Get error 6 if there is no console.
                    raise
            
            # Last resort: call TerminateProcess if it has not yet.
            retval = 0
            try:
                self.wait(gracePeriod)
            except ProcessError, ex:
                log.info("[%s] Process.kill: calling TerminateProcess", id(self))
                win32process.TerminateProcess(self._hProcess, -1)
                win32api.Sleep(100) # wait for resources to be released

        else:
            if sig is None:
                sig = signal.SIGKILL
            try:
                os.kill(self._pid, sig)
            except OSError, ex:
                if ex.errno != 3:
                    # Ignore:   OSError: [Errno 3] No such process
                    raise

    def _close_(self, hwnd, dummy):
        """Callback used by .kill() on Windows.

        EnumWindows callback - sends WM_CLOSE to any window owned by this
        process.
        """
        threadId, processId = win32process.GetWindowThreadProcessId(hwnd)
        if processId == self._processId:
            import win32gui
            win32gui.PostMessage(hwnd, WM_CLOSE, 0, 0)


class ProcessOpen(Process):
    """Create a process and setup pipes to it standard handles.

    This is a super popen3.
    """
    # TODO:
    #   - Share some implementation with Process and ProcessProxy.
    #

    def __init__(self, cmd, mode='t', cwd=None, env=None):
        """Create a Process with proxy threads for each std handle.

        "cmd" is the command string or argument vector to run.
        "mode" (Windows only) specifies whether the pipes used to communicate
            with the child are openned in text, 't', or binary, 'b', mode.
            This is ignored on platforms other than Windows. Default is 't'.
        "cwd" optionally specifies the directory in which the child process
            should be started. Default is None, a.k.a. inherits the cwd from
            the parent.
        "env" is optionally a mapping specifying the environment in which to
            start the child. Default is None, a.k.a. inherits the environment
            of the parent.
        """
        # Keep a reference to ensure it is around for this object's destruction.
        self.__log = log
        log.info("ProcessOpen.__init__(cmd=%r, mode=%r, cwd=%r, env=%r)",
                 cmd, mode, cwd, env)
        self._cmd = cmd
        if not self._cmd:
            raise ProcessError("You must specify a command.")
        self._cwd = cwd
        self._env = env
        self._mode = mode
        if self._mode not in ('t', 'b'):
            raise ProcessError("'mode' must be 't' or 'b'.")
        self._closed = 0

        if sys.platform.startswith("win"):
            self._startOnWindows()
        else:
            self.__retvalCache = None
            self._startOnUnix()

        _registerProcess(self)

    def __del__(self):
        #XXX Should probably not rely upon this.
        logres.info("[%s] ProcessOpen.__del__()", id(self))
        self.close()
        del self.__log # drop reference

    def close(self):
        if not self._closed:
            self.__log.info("[%s] ProcessOpen.close()" % id(self))

            # Ensure that all IOBuffer's are closed. If they are not, these
            # can cause hangs. 
            try:
                self.__log.info("[%s] ProcessOpen: closing stdin (%r)."\
                                % (id(self), self.stdin))
                self.stdin.close()
            except AttributeError:
                # May not have gotten far enough in the __init__ to set
                # self.stdin, etc.
                pass
            try:
                self.__log.info("[%s] ProcessOpen: closing stdout (%r)."\
                                % (id(self), self.stdout))
                self.stdout.close()
            except AttributeError:
                # May not have gotten far enough in the __init__ to set
                # self.stdout, etc.
                pass
            try:
                self.__log.info("[%s] ProcessOpen: closing stderr (%r)."\
                                % (id(self), self.stderr))
                self.stderr.close()
            except AttributeError:
                # May not have gotten far enough in the __init__ to set
                # self.stderr, etc.
                pass

            self._closed = 1

    def _forkAndExecChildOnUnix(self, fdChildStdinRd, fdChildStdoutWr,
                                fdChildStderrWr):
        """Fork and start the child process.

        Sets self._pid as a side effect.
        """
        pid = os.fork()
        if pid == 0: # child
            os.dup2(fdChildStdinRd, 0)
            os.dup2(fdChildStdoutWr, 1)
            os.dup2(fdChildStderrWr, 2)
            self._runChildOnUnix()
        # parent
        self._pid = pid

    def _startOnUnix(self):
        # Create pipes for std handles.
        fdChildStdinRd, fdChildStdinWr = os.pipe()
        fdChildStdoutRd, fdChildStdoutWr = os.pipe()
        fdChildStderrRd, fdChildStderrWr = os.pipe()

        if self._cwd:
            oldDir = os.getcwd()
            try:
                os.chdir(self._cwd)
            except OSError, ex:
                raise ProcessError(msg=str(ex), errno=ex.errno)
        self._forkAndExecChildOnUnix(fdChildStdinRd, fdChildStdoutWr,
                                     fdChildStderrWr)
        if self._cwd:
            os.chdir(oldDir)

        os.close(fdChildStdinRd)
        os.close(fdChildStdoutWr)
        os.close(fdChildStderrWr)

        self.stdin = _FileWrapper(descriptor=fdChildStdinWr)
        logres.info("[%s] ProcessOpen._start(): create child stdin: %r",
                    id(self), self.stdin)
        self.stdout = _FileWrapper(descriptor=fdChildStdoutRd)
        logres.info("[%s] ProcessOpen._start(): create child stdout: %r",
                    id(self), self.stdout)
        self.stderr = _FileWrapper(descriptor=fdChildStderrRd)
        logres.info("[%s] ProcessOpen._start(): create child stderr: %r",
                    id(self), self.stderr)

    def _startOnWindows(self):
        if type(self._cmd) in (types.ListType, types.TupleType):
            # An arg vector was passed in.
            cmd = _joinArgv(self._cmd)
        else:
            cmd = self._cmd

        # Create pipes for std handles.
        # (Set the bInheritHandle flag so pipe handles are inherited.)
        saAttr = pywintypes.SECURITY_ATTRIBUTES()
        saAttr.bInheritHandle = 1
        #XXX Should maybe try with os.pipe. Dunno what that does for
        #    inheritability though.
        hChildStdinRd, hChildStdinWr = win32pipe.CreatePipe(saAttr, 0) 
        hChildStdoutRd, hChildStdoutWr = win32pipe.CreatePipe(saAttr, 0) 
        hChildStderrRd, hChildStderrWr = win32pipe.CreatePipe(saAttr, 0) 

        try:
            # Duplicate the parent ends of the pipes so they are not
            # inherited. 
            hChildStdinWrDup = win32api.DuplicateHandle(
                win32api.GetCurrentProcess(),
                hChildStdinWr,
                win32api.GetCurrentProcess(),
                0,
                0, # not inherited
                DUPLICATE_SAME_ACCESS)
            win32api.CloseHandle(hChildStdinWr)
            self._hChildStdinWr = hChildStdinWrDup
            hChildStdoutRdDup = win32api.DuplicateHandle(
                win32api.GetCurrentProcess(),
                hChildStdoutRd,
                win32api.GetCurrentProcess(),
                0,
                0, # not inherited
                DUPLICATE_SAME_ACCESS)
            win32api.CloseHandle(hChildStdoutRd)
            self._hChildStdoutRd = hChildStdoutRdDup
            hChildStderrRdDup = win32api.DuplicateHandle(