inotify: server: new data structure to keep track of changes.

== Rationale for the new structure ==

Current structure was a dictionary tree. One directory was tracked
as a dictionary:
 - keys: file/subdir name
 - values:
    - for a file, the status (a/r/m/...)
    - for a subdir, the directory representing the subdir

It allowed efficient lookups, no matter of the type of the terminal leaf:
    for part in path.split('/'): tree = tree[part]

However, there is no way to represent a directory and a file with the same name
because keys are conflicting in the dictionary. Concrete example:

Initial state:

root dir
 |- foo (file)
 |- bar (file)

# data state is: {'foo': 'n', 'bar': 'n'}

Remove foo:

root dir
 |- bar (file)

# Data becomes {'foo': 'r'} until next commit.

Add foo, as a directory, and foo/barbar file:

root dir
 |- bar (file)
 |-> foo (dir)
  |- barbar (file)

# New state should be represented as:
  {'foo': {'barbar': 'a'}, 'bar': 'n'}
  however, the key "foo" is already used and represents the old file.

The dirstate:
 D foo
 A foo/barbar
cannot be represented, hence the need for a new structure.

== The new structure ==

'directory' class. Represents one directory level.
* Notable attributes:
  Two dictionaries:
   - 'files' Maps filename -> status for the current dir.
   - 'dirs' Maps subdir's name -> directory object representing the subdir
* methods
  - walk(), formerly server.walk
  - lookup(), old server.lookup
  - dir(), old server.dir

This new class allows embedding all the tree walks/lookups in its own class,
instead of having everything mixed together in server.

Incidently, since files and directories are not stored in the same
dictionaries, we are solving the previous key conflict problem.

The small drawback is that lookup operation is a bit more complex:
for a path a/b/c/d/e we have to check twice the leaf, if e is a directory or a
file.

hgext/inotify/server.py

@@ -1,822 +1,869 b''
 # server.py - inotify status server
 #
 # Copyright 2006, 2007, 2008 Bryan O'Sullivan <[e-mail]>
 # Copyright 2007, 2008 Brendan Cully <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2, incorporated herein by reference.
 
 from mercurial.i18n import _
 from mercurial import osutil, util
 import common
 import errno, os, select, socket, stat, struct, sys, tempfile, time
 
 try:
     import linux as inotify
     from linux import watcher
 except ImportError:
     raise
 
 class AlreadyStartedException(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 walkrepodirs(repo):
     '''Iterate over all subdirectories of this repo.
     Exclude the .hg directory, any nested repos, and ignored dirs.'''
     rootslash = repo.root + os.sep
 
     def walkit(dirname, top):
         fullpath = rootslash + dirname
         try:
             for name, kind in osutil.listdir(fullpath):
                 if kind == stat.S_IFDIR:
                     if name == '.hg':
                         if not top:
                             return
                     else:
                         d = join(dirname, name)
                         if repo.dirstate._ignore(d):
                             continue
                         for subdir in walkit(d, False):
                             yield subdir
         except OSError, err:
             if err.errno not in walk_ignored_errors:
                 raise
         yield fullpath
 
     return walkit('', True)
 
 def walk(repo, root):
     '''Like os.walk, but only yields regular files.'''
 
     # This function is critical to performance during startup.
 
     rootslash = repo.root + os.sep
 
     def walkit(root, reporoot):
         files, dirs = [], []
 
         try:
             fullpath = rootslash + 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 repo.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 not in walk_ignored_errors:
                 raise
 
     return walkit(root, root == '')
 
 def _explain_watch_limit(ui, repo):
     path = '/proc/sys/fs/inotify/max_user_watches'
     try:
         limit = int(file(path).read())
     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(repo)))
     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')
                      % repo.root)
 
 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[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 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):
+        """
+        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():
+            for e in dir.walk(states):
+                yield e
+
+    def lookup(self, states, path):
+        """
+        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
+            return
+
+        try:
+            # if path is a directory, walk it
+            for file, st in tree.dirs[last].walk(states):
+                yield file
+        except KeyError:
+            try:
+                if tree.files[last] in states:
+                    # path is a file
+                    yield path
+            except KeyError:
+                # path is not tracked
+                pass
+
 class repowatcher(pollable):
     """
     Watches inotify events
     """
     statuskeys = 'almr!?'
     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, repo):
         self.ui = ui
         self.repo = repo
         self.wprefix = self.repo.wjoin('')
         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.tree = {}
+        self.tree = directory()
         self.statcache = {}
-        self.statustrees = dict([(s, {}) for s in self.statuskeys])
+        self.statustrees = dict([(s, directory()) for s in self.statuskeys])
 
         self.last_event = None
 
         self.lastevent = {}
 
         self.register(timeout=None)
 
         self.ds_info = self.dirstate_info()
         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 dirstate_info(self):
         try:
             st = os.lstat(self.repo.join('dirstate'))
             return st.st_mtime, st.st_ino
         except OSError, err:
             if err.errno != errno.ENOENT:
                 raise
             return 0, 0
 
     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[len(self.wprefix):])
             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.repo)
 
     def setup(self):
         self.ui.note(_('watching directories under %r\n') % self.repo.root)
         self.add_watch(self.repo.path, inotify.IN_DELETE)
         self.check_dirstate()
 
-    def dir(self, tree, path):
-        if path:
-            for name in path.split('/'):
-                tree = tree.setdefault(name, {})
-        return tree
-
-    def lookup(self, path, tree):
-        if path:
-            try:
-                for name in path.split('/'):
-                    tree = tree[name]
-            except KeyError:
-                return 'x'
-            except TypeError:
-                return 'd'
-        return tree
-
     def filestatus(self, fn, st):
         try:
             type_, mode, size, time = self.repo.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.repo.dirstate._ignore(fn):
             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 or directory.
+        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.dir(self.tree, root)
+        d = self.tree.dir(root)
 
-        oldstatus = d.get(fn)
+        oldstatus = d.files.get(fn)
         # oldstatus can be either:
         # - None : fn is new
         # - a char in statuskeys: fn is a (tracked) file
-        # - a dict: fn is a directory
-        isdir = isinstance(oldstatus, dict)
 
         if self.ui.debugflag and oldstatus != newstatus:
-            if isdir:
-                self.ui.note(_('status: %r dir(%d) -> %s\n') %
-                             (wfn, len(oldstatus), newstatus))
-            else:
-                self.ui.note(_('status: %r %s -> %s\n') %
+            self.ui.note(_('status: %r %s -> %s\n') %
                              (wfn, oldstatus, newstatus))
-        if not isdir:
-            if oldstatus and oldstatus in self.statuskeys \
-                and oldstatus != newstatus:
-                del self.dir(self.statustrees[oldstatus], root)[fn]
-            if newstatus and newstatus != 'i':
-                d[fn] = newstatus
-                if newstatus in self.statuskeys:
-                    dd = self.dir(self.statustrees[newstatus], root)
-                    if oldstatus != newstatus or fn not in dd:
-                        dd[fn] = newstatus
-            else:
-                d.pop(fn, None)
+
+        if oldstatus and oldstatus in self.statuskeys \
+            and oldstatus != newstatus:
+            del self.statustrees[oldstatus].dir(root).files[fn]
+        if newstatus and newstatus != 'i':
+            d.files[fn] = newstatus
+            if newstatus in self.statuskeys:
+                dd = self.statustrees[newstatus].dir(root)
+                if oldstatus != newstatus or fn not in dd.files:
+                    dd.files[fn] = newstatus
+        else:
+            d.files.pop(fn, None)
 
 
     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.walk(key, self.statustrees[key]):
+        for wfn, ignore in self.statustrees[key].walk(key):
             if wfn not in self.repo.dirstate:
                 nuke.append(wfn)
         for wfn in nuke:
             root, fn = split(wfn)
-            del self.dir(self.statustrees[key], root)[fn]
-            del self.dir(self.tree, root)[fn]
+            del self.statustrees[key].dir(root).files[fn]
+            del self.tree.dir(root).files[fn]
 
     def scan(self, topdir=''):
         ds = self.repo.dirstate._map.copy()
         self.add_watch(join(self.repo.root, topdir), self.mask)
         for root, dirs, files in walk(self.repo, topdir):
             for d in dirs:
                 self.add_watch(join(root, d), self.mask)
             wroot = root[len(self.wprefix):]
             for fn in files:
                 wfn = 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')
 
     def check_dirstate(self):
         ds_info = self.dirstate_info()
         if ds_info == self.ds_info:
             return
         self.ds_info = ds_info
         if not self.ui.debugflag:
             self.last_event = None
         self.ui.note(_('%s dirstate reload\n') % self.event_time())
         self.repo.dirstate.invalidate()
         self.handle_timeout()
         self.scan()
         self.ui.note(_('%s end dirstate reload\n') % self.event_time())
 
-    def walk(self, states, tree, prefix=''):
-        # This is the "inner loop" when talking to the client.
-
-        for name, val in tree.iteritems():
-            path = join(prefix, name)
-            try:
-                if val in states:
-                    yield path, val
-            except TypeError:
-                for p in self.walk(states, val, path):
-                    yield p
-
     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.repo.dirstate.__dict__:
             delattr(self.repo.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
 
     @eventaction('c')
     def created(self, wpath):
         if wpath == '.hgignore':
             self.update_hgignore()
         try:
             st = self.stat(wpath)
             if stat.S_ISREG(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.repo.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/'):
             if wpath == '.hg/wlock':
                 self.check_dirstate()
             return
 
         self.deletefile(wpath, self.repo.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.dir(self.tree, wpath).copy()
-            for wfn, ignore in self.walk('?', tree):
-                self.deletefile(join(wpath, wfn), '?')
+            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:
             assert evt.fullpath.startswith(self.wprefix)
             wpath = evt.fullpath[len(self.wprefix):]
 
             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:
             if self.ui.debugflag:
                 self.ui.note(_('%s hooking back up with %d bytes readable\n') %
                              (self.event_time(), self.threshold.readable()))
             self.read_events(0)
             self.register(timeout=None)
 
         self.timeout = None
 
     def shutdown(self):
         self.watcher.close()
 
     def debug(self):
         """
         Returns a sorted list of relatives paths currently watched,
         for debugging purposes.
         """
         return sorted(tuple[0][len(self.wprefix):] for tuple in self.watcher)
 
 class server(pollable):
     """
     Listens for client queries on unix socket inotify.sock
     """
     def __init__(self, ui, repo, repowatcher, timeout):
         self.ui = ui
         self.repo = repo
         self.repowatcher = repowatcher
         self.sock = socket.socket(socket.AF_UNIX)
         self.sockpath = self.repo.join('inotify.sock')
         self.realsockpath = None
         try:
             self.sock.bind(self.sockpath)
         except socket.error, err:
             if err[0] == errno.EADDRINUSE:
                 raise AlreadyStartedException(_('could not start server: %s')
                                               % err[1])
             if err[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(_('could not start server: %s')
                                                       % inst.strerror)
                     raise
             else:
                 raise
         self.sock.listen(5)
         self.fileno = self.sock.fileno
         self.register(timeout=timeout)
 
     def handle_timeout(self):
         pass
 
     def answer_stat_query(self, cs):
         names = cs.read().split('\0')
 
         states = names.pop()
 
         self.ui.note(_('answering query for %r\n') % states)
 
         if self.repowatcher.timeout:
             # We got a query while a rescan is pending.  Make sure we
             # rescan before responding, or we could give back a wrong
             # answer.
             self.repowatcher.handle_timeout()
 
         if not names:
             def genresult(states, tree):
-                for fn, state in self.repowatcher.walk(states, tree):
+                for fn, state in tree.walk(states):
                     yield fn
         else:
             def genresult(states, tree):
                 for fn in names:
-                    l = self.repowatcher.lookup(fn, tree)
-                    try:
-                        if l in states:
-                            yield fn
-                    except TypeError:
-                        for f, s in self.repowatcher.walk(states, l, fn):
-                            yield f
+                    for f in tree.lookup(states, fn):
+                        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 [],
             ]]
 
     def answer_dbug_query(self):
         return ['\0'.join(self.repowatcher.debug())]
 
     def handle_pollevents(self, events):
         for e in events:
             self.handle_pollevent()
 
     def handle_pollevent(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[0] != errno.EPIPE:
                 raise
 
     def shutdown(self):
         self.sock.close()
         try:
             os.unlink(self.sockpath)
             if self.realsockpath:
                 os.unlink(self.realsockpath)
                 os.rmdir(os.path.dirname(self.realsockpath))
         except OSError, err:
             if err.errno != errno.ENOENT:
                 raise
 
 class master(object):
     def __init__(self, ui, repo, timeout=None):
         self.ui = ui
         self.repo = repo
         self.repowatcher = repowatcher(ui, repo)
         self.server = server(ui, repo, self.repowatcher, timeout)
 
     def shutdown(self):
         for obj in pollable.instances.itervalues():
             obj.shutdown()
 
     def run(self):
         self.repowatcher.setup()
         self.ui.note(_('finished setup\n'))
         if os.getenv('TIME_STARTUP'):
             sys.exit(0)
         pollable.run()
 
 def start(ui, repo):
     def closefds(ignore):
         # (from python bug #1177468)
         # close all inherited file descriptors
         # Python 2.4.1 and later use /dev/urandom to seed the random module's RNG
         # a file descriptor is kept internally as os._urandomfd (created on demand
         # the first time os.urandom() is called), and should not be closed
         try:
             os.urandom(4)
             urandom_fd = getattr(os, '_urandomfd', None)
         except AttributeError:
             urandom_fd = None
         ignore.append(urandom_fd)
         for fd in range(3, 256):
             if fd in ignore:
                 continue
             try:
                 os.close(fd)
             except OSError:
                 pass
 
     m = master(ui, repo)
     sys.stdout.flush()
     sys.stderr.flush()
 
     pid = os.fork()
     if pid:
         return pid
 
     closefds(pollable.instances.keys())
     os.setsid()
 
     fd = os.open('/dev/null', os.O_RDONLY)
     os.dup2(fd, 0)
     if fd > 0:
         os.close(fd)
 
     fd = os.open(ui.config('inotify', 'log', '/dev/null'),
                  os.O_RDWR | os.O_CREAT | os.O_TRUNC)
     os.dup2(fd, 1)
     os.dup2(fd, 2)
     if fd > 2:
         os.close(fd)
 
     try:
         m.run()
     finally:
         m.shutdown()
         os._exit(0)