# linuxserver.py - inotify status server for linux

#

# Copyright 2006, 2007, 2008 Bryan O'Sullivan <bos@serpentine.com>

# Copyright 2007, 2008 Brendan Cully <brendan@kublai.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

from mercurial.i18n import _

from mercurial import osutil, util, error

import server

import errno, os, select, stat, sys, time

try:

    import linux as inotify

    from linux import watcher

except ImportError:

    raise

def walkrepodirs(dirstate, absroot):

    '''Iterate over all subdirectories of this repo.

    Exclude the .hg directory, any nested repos, and ignored dirs.'''

    def walkit(dirname, top):

        fullpath = server.join(absroot, dirname)

        try:

            for name, kind in osutil.listdir(fullpath):

                if kind == stat.S_IFDIR:

                    if name == '.hg':

                        if not top:

                            return

                    else:

                        d = server.join(dirname, name)

                        if dirstate._ignore(d):

                            continue

                        for subdir in walkit(d, False):

                            yield subdir

        except OSError, err:

            if err.errno not in server.walk_ignored_errors:

                raise

        yield fullpath

    return walkit('', True)

def _explain_watch_limit(ui, dirstate, rootabs):

    path = '/proc/sys/fs/inotify/max_user_watches'

    try:

        limit = int(util.readfile(path))

    except IOError, err:

        if err.errno != errno.ENOENT:

            raise

        raise util.Abort(_('this system does not seem to '

                           'support inotify'))

    ui.warn(_('*** the current per-user limit on the number '

              'of inotify watches is %s\n') % limit)

    ui.warn(_('*** this limit is too low to watch every '

              'directory in this repository\n'))

    ui.warn(_('*** counting directories: '))

    ndirs = len(list(walkrepodirs(dirstate, rootabs)))

    ui.warn(_('found %d\n') % ndirs)

    newlimit = min(limit, 1024)

    while newlimit < ((limit + ndirs) * 1.1):

        newlimit *= 2

    ui.warn(_('*** to raise the limit from %d to %d (run as root):\n') %

            (limit, newlimit))

    ui.warn(_('***  echo %d > %s\n') % (newlimit, path))

    raise util.Abort(_('cannot watch %s until inotify watch limit is raised')

                     % rootabs)

class pollable(object):

    """

    Interface to support polling.

    The file descriptor returned by fileno() is registered to a polling

    object.

    Usage:

        Every tick, check if an event has happened since the last tick:

        * If yes, call handle_events

        * If no, call handle_timeout

    """

    poll_events = select.POLLIN

    instances = {}

    poll = select.poll()

    def fileno(self):

        raise NotImplementedError

    def handle_events(self, events):

        raise NotImplementedError

    def handle_timeout(self):

        raise NotImplementedError

    def shutdown(self):

        raise NotImplementedError

    def register(self, timeout):

        fd = self.fileno()

        pollable.poll.register(fd, pollable.poll_events)

        pollable.instances[fd] = self

        self.registered = True

        self.timeout = timeout

    def unregister(self):

        pollable.poll.unregister(self)

        self.registered = False

    @classmethod

    def run(cls):

        while True:

            timeout = None

            timeobj = None

            for obj in cls.instances.itervalues():

                if obj.timeout is not None and (timeout is None

                                                or obj.timeout < timeout):

                    timeout, timeobj = obj.timeout, obj

            try:

                events = cls.poll.poll(timeout)

            except select.error, err:

                if err.args[0] == errno.EINTR:

                    continue

                raise

            if events:

                by_fd = {}

                for fd, event in events:

                    by_fd.setdefault(fd, []).append(event)

                for fd, events in by_fd.iteritems():

                    cls.instances[fd].handle_pollevents(events)

            elif timeobj:

                timeobj.handle_timeout()

def eventaction(code):

    """

    Decorator to help handle events in repowatcher

    """

    def decorator(f):

        def wrapper(self, wpath):

            if code == 'm' and wpath in self.lastevent and \

                self.lastevent[wpath] in 'cm':

                return

            self.lastevent[wpath] = code

            self.timeout = 250

            f(self, wpath)

        wrapper.func_name = f.func_name

        return wrapper

    return decorator

class repowatcher(server.repowatcher, pollable):

    """

    Watches inotify events

    """

    mask = (

        inotify.IN_ATTRIB |

        inotify.IN_CREATE |

        inotify.IN_DELETE |

        inotify.IN_DELETE_SELF |

        inotify.IN_MODIFY |

        inotify.IN_MOVED_FROM |

        inotify.IN_MOVED_TO |

        inotify.IN_MOVE_SELF |

        inotify.IN_ONLYDIR |

        inotify.IN_UNMOUNT |

        0)

    def __init__(self, ui, dirstate, root):

        server.repowatcher.__init__(self, ui, dirstate, root)

        self.lastevent = {}

        self.dirty = False

        try:

            self.watcher = watcher.watcher()

        except OSError, err:

            raise util.Abort(_('inotify service not available: %s') %

                             err.strerror)

        self.threshold = watcher.threshold(self.watcher)

        self.fileno = self.watcher.fileno

        self.register(timeout=None)

        self.handle_timeout()

        self.scan()

    def event_time(self):

        last = self.last_event

        now = time.time()

        self.last_event = now

        if last is None:

            return 'start'

        delta = now - last

        if delta < 5:

            return '+%.3f' % delta

        if delta < 50:

            return '+%.2f' % delta

        return '+%.1f' % delta

    def add_watch(self, path, mask):

        if not path:

            return

        if self.watcher.path(path) is None:

            if self.ui.debugflag:

                self.ui.note(_('watching %r\n') % path[self.prefixlen:])

            try:

                self.watcher.add(path, mask)

            except OSError, err:

                if err.errno in (errno.ENOENT, errno.ENOTDIR):

                    return

                if err.errno != errno.ENOSPC:

                    raise

                _explain_watch_limit(self.ui, self.dirstate, self.wprefix)

    def setup(self):

        self.ui.note(_('watching directories under %r\n') % self.wprefix)

        self.add_watch(self.wprefix + '.hg', inotify.IN_DELETE)

    def scan(self, topdir=''):

        ds = self.dirstate._map.copy()

        self.add_watch(server.join(self.wprefix, topdir), self.mask)

        for root, dirs, files in server.walk(self.dirstate, self.wprefix,

                                             topdir):

            for d in dirs:

                self.add_watch(server.join(root, d), self.mask)

            wroot = root[self.prefixlen:]

            for fn in files:

                wfn = server.join(wroot, fn)

                self.updatefile(wfn, self.getstat(wfn))

                ds.pop(wfn, None)

        wtopdir = topdir

        if wtopdir and wtopdir[-1] != '/':

            wtopdir += '/'

        for wfn, state in ds.iteritems():

            if not wfn.startswith(wtopdir):

                continue

            try:

                st = self.stat(wfn)

            except OSError:

                status = state[0]

                self.deletefile(wfn, status)

            else:

                self.updatefile(wfn, st)

        self.check_deleted('!')

        self.check_deleted('r')

    @eventaction('c')

    def created(self, wpath):

        if wpath == '.hgignore':

            self.update_hgignore()

        try:

            st = self.stat(wpath)

            if stat.S_ISREG(st[0]) or stat.S_ISLNK(st[0]):

                self.updatefile(wpath, st)

        except OSError:

            pass

    @eventaction('m')

    def modified(self, wpath):

        if wpath == '.hgignore':

            self.update_hgignore()

        try:

            st = self.stat(wpath)

            if stat.S_ISREG(st[0]):

                if self.dirstate[wpath] in 'lmn':

                    self.updatefile(wpath, st)

        except OSError:

            pass

    @eventaction('d')

    def deleted(self, wpath):

        if wpath == '.hgignore':

            self.update_hgignore()

        elif wpath.startswith('.hg/'):

            return

        self.deletefile(wpath, self.dirstate[wpath])

    def process_create(self, wpath, evt):

        if self.ui.debugflag:

            self.ui.note(_('%s event: created %s\n') %

                         (self.event_time(), wpath))

        if evt.mask & inotify.IN_ISDIR:

            self.scan(wpath)

        else:

            self.created(wpath)

    def process_delete(self, wpath, evt):

        if self.ui.debugflag:

            self.ui.note(_('%s event: deleted %s\n') %

                         (self.event_time(), wpath))

        if evt.mask & inotify.IN_ISDIR:

            tree = self.tree.dir(wpath)

            todelete = [wfn for wfn, ignore in tree.walk('?')]

            for fn in todelete:

                self.deletefile(fn, '?')

            self.scan(wpath)

        else:

            self.deleted(wpath)

    def process_modify(self, wpath, evt):

        if self.ui.debugflag:

            self.ui.note(_('%s event: modified %s\n') %

                         (self.event_time(), wpath))

        if not (evt.mask & inotify.IN_ISDIR):

            self.modified(wpath)

    def process_unmount(self, evt):

        self.ui.warn(_('filesystem containing %s was unmounted\n') %

                     evt.fullpath)

        sys.exit(0)

    def handle_pollevents(self, events):

        if self.ui.debugflag:

            self.ui.note(_('%s readable: %d bytes\n') %

                         (self.event_time(), self.threshold.readable()))

        if not self.threshold():

            if self.registered:

                if self.ui.debugflag:

                    self.ui.note(_('%s below threshold - unhooking\n') %

                                 (self.event_time()))

                self.unregister()

                self.timeout = 250

        else:

            self.read_events()

    def read_events(self, bufsize=None):

        events = self.watcher.read(bufsize)

        if self.ui.debugflag:

            self.ui.note(_('%s reading %d events\n') %

                         (self.event_time(), len(events)))

        for evt in events:

            if evt.fullpath == self.wprefix[:-1]:

                # events on the root of the repository

                # itself, e.g. permission changes or repository move

                continue

            assert evt.fullpath.startswith(self.wprefix)

            wpath = evt.fullpath[self.prefixlen:]

            # paths have been normalized, wpath never ends with a '/'

            if wpath.startswith('.hg/') and evt.mask & inotify.IN_ISDIR:

                # ignore subdirectories of .hg/ (merge, patches...)

                continue

            if wpath == ".hg/wlock":

                if evt.mask & inotify.IN_DELETE:

                    self.dirstate.invalidate()

                    self.dirty = False

                    self.scan()

                elif evt.mask & inotify.IN_CREATE:

                    self.dirty = True

            else:

                if self.dirty:

                    continue

                if evt.mask & inotify.IN_UNMOUNT:

                    self.process_unmount(wpath, evt)

                elif evt.mask & (inotify.IN_MODIFY | inotify.IN_ATTRIB):

                    self.process_modify(wpath, evt)

                elif evt.mask & (inotify.IN_DELETE | inotify.IN_DELETE_SELF |

                                 inotify.IN_MOVED_FROM):

                    self.process_delete(wpath, evt)

                elif evt.mask & (inotify.IN_CREATE | inotify.IN_MOVED_TO):

                    self.process_create(wpath, evt)

        self.lastevent.clear()

    def handle_timeout(self):

        if not self.registered: