Python os.confstr方法代码示例

# 需要导入模块: import os [as 别名]
# 或者: from os import confstr [as 别名]
def _glibc_version_string_confstr():
    # type: () -> Optional[str]
    """
    Primary implementation of glibc_version_string using os.confstr.
    """
    # os.confstr is quite a bit faster than ctypes.DLL. It's also less likely
    # to be broken or missing. This strategy is used in the standard library
    # platform module.
    # https://github.com/python/cpython/blob/fcf1d003bf4f0100c9d0921ff3d70e1127ca1b71/Lib/platform.py#L175-L183
    try:
        # os.confstr("CS_GNU_LIBC_VERSION") returns a string like "glibc 2.17".
        version_string = os.confstr(  # type: ignore[attr-defined] # noqa: F821
            "CS_GNU_LIBC_VERSION"
        )
        assert version_string is not None
        _, version = version_string.split()  # type: Tuple[str, str]
    except (AssertionError, AttributeError, OSError, ValueError):
        # os.confstr() or CS_GNU_LIBC_VERSION not available (or a bad value)...
        return None
    return version 

# 需要导入模块: import os [as 别名]
# 或者: from os import confstr [as 别名]
def glibc_version_string_confstr():
    # type: () -> Optional[str]
    "Primary implementation of glibc_version_string using os.confstr."
    # os.confstr is quite a bit faster than ctypes.DLL. It's also less likely
    # to be broken or missing. This strategy is used in the standard library
    # platform module:
    # https://github.com/python/cpython/blob/fcf1d003bf4f0100c9d0921ff3d70e1127ca1b71/Lib/platform.py#L175-L183
    if sys.platform == "win32":
        return None
    try:
        # os.confstr("CS_GNU_LIBC_VERSION") returns a string like "glibc 2.17":
        _, version = os.confstr("CS_GNU_LIBC_VERSION").split()
    except (AttributeError, OSError, ValueError):
        # os.confstr() or CS_GNU_LIBC_VERSION not available (or a bad value)...
        return None
    return version 

# 需要导入模块: import os [as 别名]
# 或者: from os import confstr [as 别名]
def glibc_version_string_confstr():
    # type: () -> Optional[str]
    "Primary implementation of glibc_version_string using os.confstr."
    # os.confstr is quite a bit faster than ctypes.DLL. It's also less likely
    # to be broken or missing. This strategy is used in the standard library
    # platform module:
    # https://github.com/python/cpython/blob/fcf1d003bf4f0100c9d0921ff3d70e1127ca1b71/Lib/platform.py#L175-L183
    try:
        # os.confstr("CS_GNU_LIBC_VERSION") returns a string like "glibc 2.17":
        _, version = os.confstr("CS_GNU_LIBC_VERSION").split()
    except (AttributeError, OSError, ValueError):
        # os.confstr() or CS_GNU_LIBC_VERSION not available (or a bad value)...
        return None
    return version 

# 需要导入模块: import os [as 别名]
# 或者: from os import confstr [as 别名]
def find_executable(executable, path=None):
    """Tries to find 'executable' in the directories listed in 'path'.

    A string listing directories separated by 'os.pathsep'; defaults to
    os.environ['PATH'].  Returns the complete filename or None if not found.
    """
    _, ext = os.path.splitext(executable)
    if (sys.platform == 'win32') and (ext != '.exe'):
        executable = executable + '.exe'

    if os.path.isfile(executable):
        return executable

    if path is None:
        path = os.environ.get('PATH', None)
        if path is None:
            try:
                path = os.confstr("CS_PATH")
            except (AttributeError, ValueError):
                # os.confstr() or CS_PATH is not available
                path = os.defpath
        # bpo-35755: Don't use os.defpath if the PATH environment variable is
        # set to an empty string

    # PATH='' doesn't match, whereas PATH=':' looks in the current directory
    if not path:
        return None

    paths = path.split(os.pathsep)
    for p in paths:
        f = os.path.join(p, executable)
        if os.path.isfile(f):
            # the file exists, we have a shot at spawn working
            return f
    return None 

# 需要导入模块: import os [as 别名]
# 或者: from os import confstr [as 别名]
def which(cmd, mode=os.F_OK | os.X_OK, path=None):
        """Given a command, mode, and a PATH string, return the path which
        conforms to the given mode on the PATH, or None if there is no such
        file.
        `mode` defaults to os.F_OK | os.X_OK. `path` defaults to the result
        of os.environ.get("PATH"), or can be overridden with a custom search
        path.
        """
        def _access_check(fn, mode):
            return (os.path.exists(fn) and os.access(fn, mode)
                    and not os.path.isdir(fn))
        if os.path.dirname(cmd):
            if _access_check(cmd, mode):
                return cmd
            return None

        if path is None:
            path = os.environ.get("PATH", None)
            if path is None:
                try:
                    path = os.confstr("CS_PATH")
                except (AttributeError, ValueError):
                    # os.confstr() or CS_PATH is not available
                    path = os.defpath
        # PATH='' doesn't match, whereas PATH=':' looks in the current directory
        if not path:
            return None
        path = path.split(os.pathsep)

        if sys.platform == "win32":
            # The current directory takes precedence on Windows.
            if not os.curdir in path:
                path.insert(0, os.curdir)

            # PATHEXT is necessary to check on Windows.
            pathext = os.environ.get("PATHEXT", "").split(os.pathsep)
            if any(cmd.lower().endswith(ext.lower()) for ext in pathext):
                files = [cmd]
            else:
                files = [cmd + ext for ext in pathext]
        else:
            files = [cmd]

        seen = set()
        for dir in path:
            normdir = os.path.normcase(dir)
            if not normdir in seen:
                seen.add(normdir)
                for thefile in files:
                    name = os.path.join(dir, thefile)
                    if _access_check(name, mode):
                        return name
        return None