hgext/inotify/server.py

building: build inotify for sys.platform='linux*'

If Python interpreter was built under Linux 3.x kernel, it reports
sys.platform to be 'linux3' (it is fixed for Python 3, but not for 2.x).
This cancels building inotify extension, which was built only for 'linux2'
platform. Improved test checks if sys.platform begins with 'linux', and together
with test for kernel version to be greater than 2.6 it seems to cover all known
cases.

# server.py - common entry point for inotify status server
#
# Copyright 2009 Nicolas Dumazet <[e-mail]>
#
# 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 cmdutil, osutil, util
import common

import errno
import os
import socket
import stat
import struct
import sys
import tempfile

class AlreadyStartedException(Exception):
    pass
class TimeoutException(Exception):
    pass

def join(a, b):
    if a:
        if a[-1] == '/':
            return a + b
        return a + '/' + b
    return b

def split(path):
    c = path.rfind('/')
    if c == -1:
        return '', path
    return path[:c], path[c + 1:]

walk_ignored_errors = (errno.ENOENT, errno.ENAMETOOLONG)

def walk(dirstate, absroot, root):
    '''Like os.walk, but only yields regular files.'''

    # This function is critical to performance during startup.

    def walkit(root, reporoot):
        files, dirs = [], []

        try:
            fullpath = join(absroot, root)
            for name, kind in osutil.listdir(fullpath):
                if kind == stat.S_IFDIR:
                    if name == '.hg':
                        if not reporoot:
                            return
                    else:
                        dirs.append(name)
                        path = join(root, name)
                        if dirstate._ignore(path):
                            continue
                        for result in walkit(path, False):
                            yield result
                elif kind in (stat.S_IFREG, stat.S_IFLNK):
                    files.append(name)
            yield fullpath, dirs, files

        except OSError, err:
            if err.errno == errno.ENOTDIR:
                # fullpath was a directory, but has since been replaced
                # by a file.
                yield fullpath, dirs, files
            elif err.errno not in walk_ignored_errors:
                raise

    return walkit(root, root == '')

class directory(object):
    """
    Representing a directory

    * path is the relative path from repo root to this directory
    * files is a dict listing the files in this directory
        - keys are file names
        - values are file status
    * dirs is a dict listing the subdirectories
        - key are subdirectories names
        - values are directory objects
    """
    def __init__(self, relpath=''):
        self.path = relpath
        self.files = {}
        self.dirs = {}

    def dir(self, relpath):
        """
        Returns the directory contained at the relative path relpath.
        Creates the intermediate directories if necessary.
        """
        if not relpath:
            return self
        l = relpath.split('/')
        ret = self
        while l:
            next = l.pop(0)
            try:
                ret = ret.dirs[next]
            except KeyError:
                d = directory(join(ret.path, next))
                ret.dirs[next] = d
                ret = d
        return ret

    def walk(self, states, visited=None):
        """
        yield (filename, status) pairs for items in the trees
        that have status in states.
        filenames are relative to the repo root
        """
        for file, st in self.files.iteritems():
            if st in states:
                yield join(self.path, file), st
        for dir in self.dirs.itervalues():
            if visited is not None:
                visited.add(dir.path)
            for e in dir.walk(states):
                yield e

    def lookup(self, states, path, visited):
        """
        yield root-relative filenames that match path, and whose
        status are in states:
        * if path is a file, yield path
        * if path is a directory, yield directory files
        * if path is not tracked, yield nothing
        """
        if path[-1] == '/':
            path = path[:-1]

        paths = path.split('/')

        # we need to check separately for last node
        last = paths.pop()

        tree = self
        try:
            for dir in paths:
                tree = tree.dirs[dir]
        except KeyError:
            # path is not tracked
            visited.add(tree.path)
            return

        try:
            # if path is a directory, walk it
            target = tree.dirs[last]
            visited.add(target.path)
            for file, st in target.walk(states, visited):
                yield file
        except KeyError:
            try:
                if tree.files[last] in states:
                    # path is a file
                    visited.add(tree.path)
                    yield path
            except KeyError:
                # path is not tracked
                pass

class repowatcher(object):
    """
    Watches inotify events
    """
    statuskeys = 'almr!?'

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

        self.wprefix = join(root, '')
        self.prefixlen = len(self.wprefix)

        self.tree = directory()
        self.statcache = {}
        self.statustrees = dict([(s, directory()) for s in self.statuskeys])

        self.ds_info = self.dirstate_info()

        self.last_event = None


    def handle_timeout(self):
        pass

    def dirstate_info(self):
        try:
            st = os.lstat(self.wprefix + '.hg/dirstate')
            return st.st_mtime, st.st_ino
        except OSError, err:
            if err.errno != errno.ENOENT:
                raise
            return 0, 0

    def filestatus(self, fn, st):
        try:
            type_, mode, size, time = self.dirstate._map[fn][:4]
        except KeyError:
            type_ = '?'
        if type_ == 'n':
            st_mode, st_size, st_mtime = st
            if size == -1:
                return 'l'
            if size and (size != st_size or (mode ^ st_mode) & 0100):
                return 'm'
            if time != int(st_mtime):
                return 'l'
            return 'n'
        if type_ == '?' and self.dirstate._dirignore(fn):
            # we must check not only if the file is ignored, but if any part
            # of its path match an ignore pattern
            return 'i'
        return type_

    def updatefile(self, wfn, osstat):
        '''
        update the file entry of an existing file.

        osstat: (mode, size, time) tuple, as returned by os.lstat(wfn)
        '''

        self._updatestatus(wfn, self.filestatus(wfn, osstat))

    def deletefile(self, wfn, oldstatus):
        '''
        update the entry of a file which has been deleted.

        oldstatus: char in statuskeys, status of the file before deletion
        '''
        if oldstatus == 'r':
            newstatus = 'r'
        elif oldstatus in 'almn':
            newstatus = '!'
        else:
            newstatus = None

        self.statcache.pop(wfn, None)
        self._updatestatus(wfn, newstatus)

    def _updatestatus(self, wfn, newstatus):
        '''
        Update the stored status of a file.

        newstatus: - char in (statuskeys + 'ni'), new status to apply.
                   - or None, to stop tracking wfn
        '''
        root, fn = split(wfn)
        d = self.tree.dir(root)

        oldstatus = d.files.get(fn)
        # oldstatus can be either:
        # - None : fn is new
        # - a char in statuskeys: fn is a (tracked) file

        if self.ui.debugflag and oldstatus != newstatus:
            self.ui.note(_('status: %r %s -> %s\n') %
                             (wfn, oldstatus, newstatus))

        if oldstatus and oldstatus in self.statuskeys \
            and oldstatus != newstatus:
            del self.statustrees[oldstatus].dir(root).files[fn]

        if newstatus in (None, 'i'):
            d.files.pop(fn, None)
        elif oldstatus != newstatus:
            d.files[fn] = newstatus
            if newstatus != 'n':
                self.statustrees[newstatus].dir(root).files[fn] = newstatus

    def check_deleted(self, key):
        # Files that had been deleted but were present in the dirstate
        # may have vanished from the dirstate; we must clean them up.
        nuke = []
        for wfn, ignore in self.statustrees[key].walk(key):
            if wfn not in self.dirstate:
                nuke.append(wfn)
        for wfn in nuke:
            root, fn = split(wfn)
            del self.statustrees[key].dir(root).files[fn]
            del self.tree.dir(root).files[fn]

    def update_hgignore(self):
        # An update of the ignore file can potentially change the
        # states of all unknown and ignored files.

        # XXX If the user has other ignore files outside the repo, or
        # changes their list of ignore files at run time, we'll
        # potentially never see changes to them.  We could get the
        # client to report to us what ignore data they're using.
        # But it's easier to do nothing than to open that can of
        # worms.

        if '_ignore' in self.dirstate.__dict__:
            delattr(self.dirstate, '_ignore')
            self.ui.note(_('rescanning due to .hgignore change\n'))
            self.handle_timeout()
            self.scan()

    def getstat(self, wpath):
        try:
            return self.statcache[wpath]
        except KeyError:
            try:
                return self.stat(wpath)
            except OSError, err:
                if err.errno != errno.ENOENT:
                    raise

    def stat(self, wpath):
        try:
            st = os.lstat(join(self.wprefix, wpath))
            ret = st.st_mode, st.st_size, st.st_mtime
            self.statcache[wpath] = ret
            return ret
        except OSError:
            self.statcache.pop(wpath, None)
            raise

class socketlistener(object):
    """
    Listens for client queries on unix socket inotify.sock
    """
    def __init__(self, ui, root, repowatcher, timeout):
        self.ui = ui
        self.repowatcher = repowatcher
        self.sock = socket.socket(socket.AF_UNIX)
        self.sockpath = join(root, '.hg/inotify.sock')

        self.realsockpath = self.sockpath
        if os.path.islink(self.sockpath):
            if os.path.exists(self.sockpath):
                self.realsockpath = os.readlink(self.sockpath)
            else:
                raise util.Abort('inotify-server: cannot start: '
                                '.hg/inotify.sock is a broken symlink')
        try:
            self.sock.bind(self.realsockpath)
        except socket.error, err:
            if err.args[0] == errno.EADDRINUSE:
                raise AlreadyStartedException(_('cannot start: socket is '
                                                'already bound'))
            if err.args[0] == "AF_UNIX path too long":
                tempdir = tempfile.mkdtemp(prefix="hg-inotify-")
                self.realsockpath = os.path.join(tempdir, "inotify.sock")
                try:
                    self.sock.bind(self.realsockpath)
                    os.symlink(self.realsockpath, self.sockpath)
                except (OSError, socket.error), inst:
                    try:
                        os.unlink(self.realsockpath)
                    except:
                        pass
                    os.rmdir(tempdir)
                    if inst.errno == errno.EEXIST:
                        raise AlreadyStartedException(_('cannot start: tried '
                            'linking .hg/inotify.sock to a temporary socket but'
                            ' .hg/inotify.sock already exists'))
                    raise
            else:
                raise
        self.sock.listen(5)
        self.fileno = self.sock.fileno

    def answer_stat_query(self, cs):
        names = cs.read().split('\0')

        states = names.pop()

        self.ui.note(_('answering query for %r\n') % states)

        visited = set()
        if not names:
            def genresult(states, tree):
                for fn, state in tree.walk(states):
                    yield fn
        else:
            def genresult(states, tree):
                for fn in names:
                    for f in tree.lookup(states, fn, visited):
                        yield f

        return ['\0'.join(r) for r in [
            genresult('l', self.repowatcher.statustrees['l']),
            genresult('m', self.repowatcher.statustrees['m']),
            genresult('a', self.repowatcher.statustrees['a']),
            genresult('r', self.repowatcher.statustrees['r']),
            genresult('!', self.repowatcher.statustrees['!']),
            '?' in states
                and genresult('?', self.repowatcher.statustrees['?'])
                or [],
            [],
            'c' in states and genresult('n', self.repowatcher.tree) or [],
            visited
            ]]

    def answer_dbug_query(self):
        return ['\0'.join(self.repowatcher.debug())]

    def accept_connection(self):
        sock, addr = self.sock.accept()

        cs = common.recvcs(sock)
        version = ord(cs.read(1))

        if version != common.version:
            self.ui.warn(_('received query from incompatible client '
                           'version %d\n') % version)
            try:
                # try to send back our version to the client
                # this way, the client too is informed of the mismatch
                sock.sendall(chr(common.version))
            except:
                pass
            return

        type = cs.read(4)

        if type == 'STAT':
            results = self.answer_stat_query(cs)
        elif type == 'DBUG':
            results = self.answer_dbug_query()
        else:
            self.ui.warn(_('unrecognized query type: %s\n') % type)
            return

        try:
            try:
                v = chr(common.version)

                sock.sendall(v + type + struct.pack(common.resphdrfmts[type],
                                            *map(len, results)))
                sock.sendall(''.join(results))
            finally:
                sock.shutdown(socket.SHUT_WR)
        except socket.error, err:
            if err.args[0] != errno.EPIPE:
                raise

if sys.platform.startswith('linux'):
    import linuxserver as _server
else:
    raise ImportError

master = _server.master

def start(ui, dirstate, root, opts):
    timeout = opts.get('idle_timeout')
    if timeout:
        timeout = float(timeout) * 60000
    else:
        timeout = None

    class service(object):
        def init(self):
            try:
                self.master = master(ui, dirstate, root, timeout)
            except AlreadyStartedException, inst:
                raise util.Abort("inotify-server: %s" % inst)

        def run(self):
            try:
                try:
                    self.master.run()
                except TimeoutException:
                    pass
            finally:
                self.master.shutdown()

    if 'inserve' not in sys.argv:
        runargs = util.hgcmd() + ['inserve', '-R', root]
    else:
        runargs = util.hgcmd() + sys.argv[1:]

    pidfile = ui.config('inotify', 'pidfile')
    if opts['daemon'] and pidfile is not None and 'pid-file' not in runargs:
        runargs.append("--pid-file=%s" % pidfile)

    service = service()
    logfile = ui.config('inotify', 'log')

    appendpid = ui.configbool('inotify', 'appendpid', False)

    ui.debug('starting inotify server: %s\n' % ' '.join(runargs))
    cmdutil.service(opts, initfn=service.init, runfn=service.run,
                    logfile=logfile, runargs=runargs, appendpid=appendpid)