diff options
Diffstat (limited to 'io_blend_utils/bl_utils/pipe_non_blocking.py')
-rw-r--r-- | io_blend_utils/bl_utils/pipe_non_blocking.py | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/io_blend_utils/bl_utils/pipe_non_blocking.py b/io_blend_utils/bl_utils/pipe_non_blocking.py new file mode 100644 index 00000000..ead0a738 --- /dev/null +++ b/io_blend_utils/bl_utils/pipe_non_blocking.py @@ -0,0 +1,100 @@ +# ##### BEGIN GPL LICENSE BLOCK ##### +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License +# as published by the Free Software Foundation; either version 2 +# of the License, or (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write to the Free Software Foundation, +# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. +# +# ##### END GPL LICENSE BLOCK ##### + +# <pep8 compliant> + +""" +Example use: + + p = subprocess.Popen( + command, + stdout=subprocess.PIPE, + ) + + pipe_non_blocking_set(p.stdout.fileno()) + + try: + data = os.read(p.stdout.fileno(), 1) + except PortableBlockingIOError as ex: + if not pipe_non_blocking_is_error_blocking(ex): + raise ex +""" + + +__all__ = ( + "pipe_non_blocking_set", + "pipe_non_blocking_is_error_blocking", + "PortableBlockingIOError", + ) + +import os + + +if os.name == "nt": + # MS-Windows Version + def pipe_non_blocking_set(fd): + # Constant could define globally but avoid polluting the name-space + # thanks to: http://stackoverflow.com/questions/34504970 + import msvcrt + + from ctypes import windll, byref, wintypes, WinError, POINTER + from ctypes.wintypes import HANDLE, DWORD, BOOL + + LPDWORD = POINTER(DWORD) + + PIPE_NOWAIT = wintypes.DWORD(0x00000001) + + def pipe_no_wait(pipefd): + SetNamedPipeHandleState = windll.kernel32.SetNamedPipeHandleState + SetNamedPipeHandleState.argtypes = [HANDLE, LPDWORD, LPDWORD, LPDWORD] + SetNamedPipeHandleState.restype = BOOL + + h = msvcrt.get_osfhandle(pipefd) + + res = windll.kernel32.SetNamedPipeHandleState(h, byref(PIPE_NOWAIT), None, None) + if res == 0: + print(WinError()) + return False + return True + + return pipe_no_wait(fd) + + def pipe_non_blocking_is_error_blocking(ex): + if not isinstance(ex, PortableBlockingIOError): + return False + from ctypes import GetLastError + ERROR_NO_DATA = 232 + + return (GetLastError() == ERROR_NO_DATA) + + PortableBlockingIOError = OSError +else: + # Posix Version + def pipe_non_blocking_set(fd): + import fcntl + fl = fcntl.fcntl(fd, fcntl.F_GETFL) + fcntl.fcntl(fd, fcntl.F_SETFL, fl | os.O_NONBLOCK) + return True + + # only for compatibility with 'nt' version. + def pipe_non_blocking_is_error_blocking(ex): + if not isinstance(ex, PortableBlockingIOError): + return False + return True + + PortableBlockingIOError = BlockingIOError |