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Diffstat (limited to 'powerline/lib/inotify.py')
| -rw-r--r-- | powerline/lib/inotify.py | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/powerline/lib/inotify.py b/powerline/lib/inotify.py new file mode 100644 index 0000000..8b74a7f --- /dev/null +++ b/powerline/lib/inotify.py @@ -0,0 +1,184 @@ +# vim:fileencoding=utf-8:noet +from __future__ import (unicode_literals, division, absolute_import, print_function) + +import sys +import os +import errno +import ctypes +import struct + +from ctypes.util import find_library + +from powerline.lib.encoding import get_preferred_file_name_encoding + + +__copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>' +__docformat__ = 'restructuredtext en' + + +class INotifyError(Exception): + pass + + +_inotify = None + + +def load_inotify(): + ''' Initialize the inotify library ''' + global _inotify + if _inotify is None: + if hasattr(sys, 'getwindowsversion'): + # On windows abort before loading the C library. Windows has + # multiple, incompatible C runtimes, and we have no way of knowing + # if the one chosen by ctypes is compatible with the currently + # loaded one. + raise INotifyError('INotify not available on windows') + if sys.platform == 'darwin': + raise INotifyError('INotify not available on OS X') + if not hasattr(ctypes, 'c_ssize_t'): + raise INotifyError('You need python >= 2.7 to use inotify') + name = find_library('c') + if not name: + raise INotifyError('Cannot find C library') + libc = ctypes.CDLL(name, use_errno=True) + for function in ('inotify_add_watch', 'inotify_init1', 'inotify_rm_watch'): + if not hasattr(libc, function): + raise INotifyError('libc is too old') + # inotify_init1() + prototype = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int, use_errno=True) + init1 = prototype(('inotify_init1', libc), ((1, 'flags', 0),)) + + # inotify_add_watch() + prototype = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int, ctypes.c_char_p, ctypes.c_uint32, use_errno=True) + add_watch = prototype(('inotify_add_watch', libc), ( + (1, 'fd'), (1, 'pathname'), (1, 'mask'))) + + # inotify_rm_watch() + prototype = ctypes.CFUNCTYPE(ctypes.c_int, ctypes.c_int, ctypes.c_int, use_errno=True) + rm_watch = prototype(('inotify_rm_watch', libc), ( + (1, 'fd'), (1, 'wd'))) + + # read() + prototype = ctypes.CFUNCTYPE(ctypes.c_ssize_t, ctypes.c_int, ctypes.c_void_p, ctypes.c_size_t, use_errno=True) + read = prototype(('read', libc), ( + (1, 'fd'), (1, 'buf'), (1, 'count'))) + _inotify = (init1, add_watch, rm_watch, read) + return _inotify + + +class INotify(object): + + # See <sys/inotify.h> for the flags defined below + + # Supported events suitable for MASK parameter of INOTIFY_ADD_WATCH. + ACCESS = 0x00000001 # File was accessed. + MODIFY = 0x00000002 # File was modified. + ATTRIB = 0x00000004 # Metadata changed. + CLOSE_WRITE = 0x00000008 # Writtable file was closed. + CLOSE_NOWRITE = 0x00000010 # Unwrittable file closed. + OPEN = 0x00000020 # File was opened. + MOVED_FROM = 0x00000040 # File was moved from X. + MOVED_TO = 0x00000080 # File was moved to Y. + CREATE = 0x00000100 # Subfile was created. + DELETE = 0x00000200 # Subfile was deleted. + DELETE_SELF = 0x00000400 # Self was deleted. + MOVE_SELF = 0x00000800 # Self was moved. + + # Events sent by the kernel. + UNMOUNT = 0x00002000 # Backing fs was unmounted. + Q_OVERFLOW = 0x00004000 # Event queued overflowed. + IGNORED = 0x00008000 # File was ignored. + + # Helper events. + CLOSE = (CLOSE_WRITE | CLOSE_NOWRITE) # Close. + MOVE = (MOVED_FROM | MOVED_TO) # Moves. + + # Special flags. + ONLYDIR = 0x01000000 # Only watch the path if it is a directory. + DONT_FOLLOW = 0x02000000 # Do not follow a sym link. + EXCL_UNLINK = 0x04000000 # Exclude events on unlinked objects. + MASK_ADD = 0x20000000 # Add to the mask of an already existing watch. + ISDIR = 0x40000000 # Event occurred against dir. + ONESHOT = 0x80000000 # Only send event once. + + # All events which a program can wait on. + ALL_EVENTS = ( + ACCESS | MODIFY | ATTRIB | CLOSE_WRITE | CLOSE_NOWRITE | OPEN | + MOVED_FROM | MOVED_TO | CREATE | DELETE | DELETE_SELF | MOVE_SELF + ) + + # See <bits/inotify.h> + CLOEXEC = 0x80000 + NONBLOCK = 0x800 + + def __init__(self, cloexec=True, nonblock=True): + self._init1, self._add_watch, self._rm_watch, self._read = load_inotify() + flags = 0 + if cloexec: + flags |= self.CLOEXEC + if nonblock: + flags |= self.NONBLOCK + self._inotify_fd = self._init1(flags) + if self._inotify_fd == -1: + raise INotifyError(os.strerror(ctypes.get_errno())) + + self._buf = ctypes.create_string_buffer(5000) + self.fenc = get_preferred_file_name_encoding() + self.hdr = struct.Struct(b'iIII') + # We keep a reference to os to prevent it from being deleted + # during interpreter shutdown, which would lead to errors in the + # __del__ method + self.os = os + + def handle_error(self): + eno = ctypes.get_errno() + extra = '' + if eno == errno.ENOSPC: + extra = 'You may need to increase the inotify limits on your system, via /proc/sys/fs/inotify/max_user_*' + raise OSError(eno, self.os.strerror(eno) + str(extra)) + + def __del__(self): + # This method can be called during interpreter shutdown, which means we + # must do the absolute minimum here. Note that there could be running + # daemon threads that are trying to call other methods on this object. + try: + self.os.close(self._inotify_fd) + except (AttributeError, TypeError): + pass + + def close(self): + if hasattr(self, '_inotify_fd'): + self.os.close(self._inotify_fd) + del self.os + del self._add_watch + del self._rm_watch + del self._inotify_fd + + def read(self, get_name=True): + buf = [] + while True: + num = self._read(self._inotify_fd, self._buf, len(self._buf)) + if num == 0: + break + if num < 0: + en = ctypes.get_errno() + if en == errno.EAGAIN: + break # No more data + if en == errno.EINTR: + continue # Interrupted, try again + raise OSError(en, self.os.strerror(en)) + buf.append(self._buf.raw[:num]) + raw = b''.join(buf) + pos = 0 + lraw = len(raw) + while lraw - pos >= self.hdr.size: + wd, mask, cookie, name_len = self.hdr.unpack_from(raw, pos) + pos += self.hdr.size + name = None + if get_name: + name = raw[pos:pos + name_len].rstrip(b'\0') + pos += name_len + self.process_event(wd, mask, cookie, name) + + def process_event(self, *args): + raise NotImplementedError() |