Mercurial > hg

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/fsmonitor/pywatchman/__init__.py	Wed Mar 02 16:25:12 2016 +0000
@@ -0,0 +1,779 @@
+# Copyright 2014-present Facebook, Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+#  * Redistributions of source code must retain the above copyright notice,
+#    this list of conditions and the following disclaimer.
+#
+#  * Redistributions in binary form must reproduce the above copyright notice,
+#    this list of conditions and the following disclaimer in the documentation
+#    and/or other materials provided with the distribution.
+#
+#  * Neither the name Facebook nor the names of its contributors may be used to
+#    endorse or promote products derived from this software without specific
+#    prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import os
+import errno
+import math
+import socket
+import subprocess
+import time
+
+# Sometimes it's really hard to get Python extensions to compile,
+# so fall back to a pure Python implementation.
+try:
+    import bser
+except ImportError:
+    import pybser as bser
+
+import capabilities
+
+if os.name == 'nt':
+    import ctypes
+    import ctypes.wintypes
+
+    wintypes = ctypes.wintypes
+    GENERIC_READ = 0x80000000
+    GENERIC_WRITE = 0x40000000
+    FILE_FLAG_OVERLAPPED = 0x40000000
+    OPEN_EXISTING = 3
+    INVALID_HANDLE_VALUE = -1
+    FORMAT_MESSAGE_FROM_SYSTEM = 0x00001000
+    FORMAT_MESSAGE_ALLOCATE_BUFFER = 0x00000100
+    FORMAT_MESSAGE_IGNORE_INSERTS = 0x00000200
+    WAIT_TIMEOUT = 0x00000102
+    WAIT_OBJECT_0 = 0x00000000
+    ERROR_IO_PENDING = 997
+
+    class OVERLAPPED(ctypes.Structure):
+        _fields_ = [
+            ("Internal", wintypes.ULONG), ("InternalHigh", wintypes.ULONG),
+            ("Offset", wintypes.DWORD), ("OffsetHigh", wintypes.DWORD),
+            ("hEvent", wintypes.HANDLE)
+        ]
+
+        def __init__(self):
+            self.Offset = 0
+            self.OffsetHigh = 0
+            self.hEvent = 0
+
+    LPDWORD = ctypes.POINTER(wintypes.DWORD)
+
+    CreateFile = ctypes.windll.kernel32.CreateFileA
+    CreateFile.argtypes = [wintypes.LPSTR, wintypes.DWORD, wintypes.DWORD,
+                           wintypes.LPVOID, wintypes.DWORD, wintypes.DWORD,
+                           wintypes.HANDLE]
+    CreateFile.restype = wintypes.HANDLE
+
+    CloseHandle = ctypes.windll.kernel32.CloseHandle
+    CloseHandle.argtypes = [wintypes.HANDLE]
+    CloseHandle.restype = wintypes.BOOL
+
+    ReadFile = ctypes.windll.kernel32.ReadFile
+    ReadFile.argtypes = [wintypes.HANDLE, wintypes.LPVOID, wintypes.DWORD,
+                         LPDWORD, ctypes.POINTER(OVERLAPPED)]
+    ReadFile.restype = wintypes.BOOL
+
+    WriteFile = ctypes.windll.kernel32.WriteFile
+    WriteFile.argtypes = [wintypes.HANDLE, wintypes.LPVOID, wintypes.DWORD,
+                          LPDWORD, ctypes.POINTER(OVERLAPPED)]
+    WriteFile.restype = wintypes.BOOL
+
+    GetLastError = ctypes.windll.kernel32.GetLastError
+    GetLastError.argtypes = []
+    GetLastError.restype = wintypes.DWORD
+
+    FormatMessage = ctypes.windll.kernel32.FormatMessageA
+    FormatMessage.argtypes = [wintypes.DWORD, wintypes.LPVOID, wintypes.DWORD,
+                              wintypes.DWORD, ctypes.POINTER(wintypes.LPSTR),
+                              wintypes.DWORD, wintypes.LPVOID]
+    FormatMessage.restype = wintypes.DWORD
+
+    LocalFree = ctypes.windll.kernel32.LocalFree
+
+    GetOverlappedResultEx = ctypes.windll.kernel32.GetOverlappedResultEx
+    GetOverlappedResultEx.argtypes = [wintypes.HANDLE,
+                                      ctypes.POINTER(OVERLAPPED), LPDWORD,
+                                      wintypes.DWORD, wintypes.BOOL]
+    GetOverlappedResultEx.restype = wintypes.BOOL
+
+    CancelIoEx = ctypes.windll.kernel32.CancelIoEx
+    CancelIoEx.argtypes = [wintypes.HANDLE, ctypes.POINTER(OVERLAPPED)]
+    CancelIoEx.restype = wintypes.BOOL
+
+# 2 bytes marker, 1 byte int size, 8 bytes int64 value
+sniff_len = 13
+
+# This is a helper for debugging the client.
+_debugging = False
+if _debugging:
+
+    def log(fmt, *args):
+        print('[%s] %s' %
+              (time.strftime("%a, %d %b %Y %H:%M:%S", time.gmtime()),
+               fmt % args[:]))
+else:
+
+    def log(fmt, *args):
+        pass
+
+
+class WatchmanError(Exception):
+    pass
+
+
+class SocketTimeout(WatchmanError):
+    """A specialized exception raised for socket timeouts during communication to/from watchman.
+       This makes it easier to implement non-blocking loops as callers can easily distinguish
+       between a routine timeout and an actual error condition.
+
+       Note that catching WatchmanError will also catch this as it is a super-class, so backwards
+       compatibility in exception handling is preserved.
+    """
+
+
+class CommandError(WatchmanError):
+    """error returned by watchman
+
+    self.msg is the message returned by watchman.
+    """
+
+    def __init__(self, msg, cmd=None):
+        self.msg = msg
+        self.cmd = cmd
+        super(CommandError, self).__init__('watchman command error: %s' % msg)
+
+    def setCommand(self, cmd):
+        self.cmd = cmd
+
+    def __str__(self):
+        if self.cmd:
+            return '%s, while executing %s' % (self.msg, self.cmd)
+        return self.msg
+
+
+class Transport(object):
+    """ communication transport to the watchman server """
+    buf = None
+
+    def close(self):
+        """ tear it down """
+        raise NotImplementedError()
+
+    def readBytes(self, size):
+        """ read size bytes """
+        raise NotImplementedError()
+
+    def write(self, buf):
+        """ write some data """
+        raise NotImplementedError()
+
+    def setTimeout(self, value):
+        pass
+
+    def readLine(self):
+        """ read a line
+        Maintains its own buffer, callers of the transport should not mix
+        calls to readBytes and readLine.
+        """
+        if self.buf is None:
+            self.buf = []
+
+        # Buffer may already have a line if we've received unilateral
+        # response(s) from the server
+        if len(self.buf) == 1 and "\n" in self.buf[0]:
+            (line, b) = self.buf[0].split("\n", 1)
+            self.buf = [b]
+            return line
+
+        while True:
+            b = self.readBytes(4096)
+            if "\n" in b:
+                result = ''.join(self.buf)
+                (line, b) = b.split("\n", 1)
+                self.buf = [b]
+                return result + line
+            self.buf.append(b)
+
+
+class Codec(object):
+    """ communication encoding for the watchman server """
+    transport = None
+
+    def __init__(self, transport):
+        self.transport = transport
+
+    def receive(self):
+        raise NotImplementedError()
+
+    def send(self, *args):
+        raise NotImplementedError()
+
+    def setTimeout(self, value):
+        self.transport.setTimeout(value)
+
+
+class UnixSocketTransport(Transport):
+    """ local unix domain socket transport """
+    sock = None
+
+    def __init__(self, sockpath, timeout):
+        self.sockpath = sockpath
+        self.timeout = timeout
+
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        try:
+            sock.settimeout(self.timeout)
+            sock.connect(self.sockpath)
+            self.sock = sock
+        except socket.error as e:
+            raise WatchmanError('unable to connect to %s: %s' %
+                                (self.sockpath, e))
+
+    def close(self):
+        self.sock.close()
+        self.sock = None
+
+    def setTimeout(self, value):
+        self.timeout = value
+        self.sock.settimeout(self.timeout)
+
+    def readBytes(self, size):
+        try:
+            buf = [self.sock.recv(size)]
+            if not buf[0]:
+                raise WatchmanError('empty watchman response')
+            return buf[0]
+        except socket.timeout:
+            raise SocketTimeout('timed out waiting for response')
+
+    def write(self, data):
+        try:
+            self.sock.sendall(data)
+        except socket.timeout:
+            raise SocketTimeout('timed out sending query command')
+
+
+class WindowsNamedPipeTransport(Transport):
+    """ connect to a named pipe """
+
+    def __init__(self, sockpath, timeout):
+        self.sockpath = sockpath
+        self.timeout = int(math.ceil(timeout * 1000))
+        self._iobuf = None
+
+        self.pipe = CreateFile(sockpath, GENERIC_READ | GENERIC_WRITE, 0, None,
+                               OPEN_EXISTING, FILE_FLAG_OVERLAPPED, None)
+
+        if self.pipe == INVALID_HANDLE_VALUE:
+            self.pipe = None
+            self._raise_win_err('failed to open pipe %s' % sockpath,
+                                GetLastError())
+
+    def _win32_strerror(self, err):
+        """ expand a win32 error code into a human readable message """
+
+        # FormatMessage will allocate memory and assign it here
+        buf = ctypes.c_char_p()
+        FormatMessage(
+            FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER
+            | FORMAT_MESSAGE_IGNORE_INSERTS, None, err, 0, buf, 0, None)
+        try:
+            return buf.value
+        finally:
+            LocalFree(buf)
+
+    def _raise_win_err(self, msg, err):
+        raise IOError('%s win32 error code: %d %s' %
+                      (msg, err, self._win32_strerror(err)))
+
+    def close(self):
+        if self.pipe:
+            CloseHandle(self.pipe)
+        self.pipe = None
+
+    def readBytes(self, size):
+        """ A read can block for an unbounded amount of time, even if the
+            kernel reports that the pipe handle is signalled, so we need to
+            always perform our reads asynchronously
+        """
+
+        # try to satisfy the read from any buffered data
+        if self._iobuf:
+            if size >= len(self._iobuf):
+                res = self._iobuf
+                self.buf = None
+                return res
+            res = self._iobuf[:size]
+            self._iobuf = self._iobuf[size:]
+            return res
+
+        # We need to initiate a read
+        buf = ctypes.create_string_buffer(size)
+        olap = OVERLAPPED()
+
+        log('made read buff of size %d', size)
+
+        # ReadFile docs warn against sending in the nread parameter for async
+        # operations, so we always collect it via GetOverlappedResultEx
+        immediate = ReadFile(self.pipe, buf, size, None, olap)
+
+        if not immediate:
+            err = GetLastError()
+            if err != ERROR_IO_PENDING:
+                self._raise_win_err('failed to read %d bytes' % size,
+                                    GetLastError())
+
+        nread = wintypes.DWORD()
+        if not GetOverlappedResultEx(self.pipe, olap, nread,
+                                     0 if immediate else self.timeout, True):
+            err = GetLastError()
+            CancelIoEx(self.pipe, olap)
+
+            if err == WAIT_TIMEOUT:
+                log('GetOverlappedResultEx timedout')
+                raise SocketTimeout('timed out after waiting %dms for read' %
+                                    self.timeout)
+
+            log('GetOverlappedResultEx reports error %d', err)
+            self._raise_win_err('error while waiting for read', err)
+
+        nread = nread.value
+        if nread == 0:
+            # Docs say that named pipes return 0 byte when the other end did
+            # a zero byte write.  Since we don't ever do that, the only
+            # other way this shows up is if the client has gotten in a weird
+            # state, so let's bail out
+            CancelIoEx(self.pipe, olap)
+            raise IOError('Async read yielded 0 bytes; unpossible!')
+
+        # Holds precisely the bytes that we read from the prior request
+        buf = buf[:nread]
+
+        returned_size = min(nread, size)
+        if returned_size == nread:
+            return buf
+
+        # keep any left-overs around for a later read to consume
+        self._iobuf = buf[returned_size:]
+        return buf[:returned_size]
+
+    def write(self, data):
+        olap = OVERLAPPED()
+        immediate = WriteFile(self.pipe, ctypes.c_char_p(data), len(data),
+                              None, olap)
+
+        if not immediate:
+            err = GetLastError()
+            if err != ERROR_IO_PENDING:
+                self._raise_win_err('failed to write %d bytes' % len(data),
+                                    GetLastError())
+
+        # Obtain results, waiting if needed
+        nwrote = wintypes.DWORD()
+        if GetOverlappedResultEx(self.pipe, olap, nwrote, 0 if immediate else
+                                 self.timeout, True):
+            return nwrote.value
+
+        err = GetLastError()
+
+        # It's potentially unsafe to allow the write to continue after
+        # we unwind, so let's make a best effort to avoid that happening
+        CancelIoEx(self.pipe, olap)
+
+        if err == WAIT_TIMEOUT:
+            raise SocketTimeout('timed out after waiting %dms for write' %
+                                self.timeout)
+        self._raise_win_err('error while waiting for write of %d bytes' %
+                            len(data), err)
+
+
+class CLIProcessTransport(Transport):
+    """ open a pipe to the cli to talk to the service
+    This intended to be used only in the test harness!
+
+    The CLI is an oddball because we only support JSON input
+    and cannot send multiple commands through the same instance,
+    so we spawn a new process for each command.
+
+    We disable server spawning for this implementation, again, because
+    it is intended to be used only in our test harness.  You really
+    should not need to use the CLI transport for anything real.
+
+    While the CLI can output in BSER, our Transport interface doesn't
+    support telling this instance that it should do so.  That effectively
+    limits this implementation to JSON input and output only at this time.
+
+    It is the responsibility of the caller to set the send and
+    receive codecs appropriately.
+    """
+    proc = None
+    closed = True
+
+    def __init__(self, sockpath, timeout):
+        self.sockpath = sockpath
+        self.timeout = timeout
+
+    def close(self):
+        if self.proc:
+            self.proc.kill()
+            self.proc = None
+
+    def _connect(self):
+        if self.proc:
+            return self.proc
+        args = [
+            'watchman',
+            '--sockname={}'.format(self.sockpath),
+            '--logfile=/BOGUS',
+            '--statefile=/BOGUS',
+            '--no-spawn',
+            '--no-local',
+            '--no-pretty',
+            '-j',
+        ]
+        self.proc = subprocess.Popen(args,
+                                     stdin=subprocess.PIPE,
+                                     stdout=subprocess.PIPE)
+        return self.proc
+
+    def readBytes(self, size):
+        self._connect()
+        res = self.proc.stdout.read(size)
+        if res == '':
+            raise WatchmanError('EOF on CLI process transport')
+        return res
+
+    def write(self, data):
+        if self.closed:
+            self.closed = False
+            self.proc = None
+        self._connect()
+        res = self.proc.stdin.write(data)
+        self.proc.stdin.close()
+        self.closed = True
+        return res
+
+
+class BserCodec(Codec):
+    """ use the BSER encoding.  This is the default, preferred codec """
+
+    def _loads(self, response):
+        return bser.loads(response)
+
+    def receive(self):
+        buf = [self.transport.readBytes(sniff_len)]
+        if not buf[0]:
+            raise WatchmanError('empty watchman response')
+
+        elen = bser.pdu_len(buf[0])
+
+        rlen = len(buf[0])
+        while elen > rlen:
+            buf.append(self.transport.readBytes(elen - rlen))
+            rlen += len(buf[-1])
+
+        response = ''.join(buf)
+        try:
+            res = self._loads(response)
+            return res
+        except ValueError as e:
+            raise WatchmanError('watchman response decode error: %s' % e)
+
+    def send(self, *args):
+        cmd = bser.dumps(*args)
+        self.transport.write(cmd)
+
+
+class ImmutableBserCodec(BserCodec):
+    """ use the BSER encoding, decoding values using the newer
+        immutable object support """
+
+    def _loads(self, response):
+        return bser.loads(response, False)
+
+
+class JsonCodec(Codec):
+    """ Use json codec.  This is here primarily for testing purposes """
+    json = None
+
+    def __init__(self, transport):
+        super(JsonCodec, self).__init__(transport)
+        # optional dep on json, only if JsonCodec is used
+        import json
+        self.json = json
+
+    def receive(self):
+        line = self.transport.readLine()
+        try:
+            return self.json.loads(line)
+        except Exception as e:
+            print(e, line)
+            raise
+
+    def send(self, *args):
+        cmd = self.json.dumps(*args)
+        self.transport.write(cmd + "\n")
+
+
+class client(object):
+    """ Handles the communication with the watchman service """
+    sockpath = None
+    transport = None
+    sendCodec = None
+    recvCodec = None
+    sendConn = None
+    recvConn = None
+    subs = {}  # Keyed by subscription name
+    sub_by_root = {}  # Keyed by root, then by subscription name
+    logs = []  # When log level is raised
+    unilateral = ['log', 'subscription']
+    tport = None
+    useImmutableBser = None
+
+    def __init__(self,
+                 sockpath=None,
+                 timeout=1.0,
+                 transport=None,
+                 sendEncoding=None,
+                 recvEncoding=None,
+                 useImmutableBser=False):
+        self.sockpath = sockpath
+        self.timeout = timeout
+        self.useImmutableBser = useImmutableBser
+
+        transport = transport or os.getenv('WATCHMAN_TRANSPORT') or 'local'
+        if transport == 'local' and os.name == 'nt':
+            self.transport = WindowsNamedPipeTransport
+        elif transport == 'local':
+            self.transport = UnixSocketTransport
+        elif transport == 'cli':
+            self.transport = CLIProcessTransport
+            if sendEncoding is None:
+                sendEncoding = 'json'
+            if recvEncoding is None:
+                recvEncoding = sendEncoding
+        else:
+            raise WatchmanError('invalid transport %s' % transport)
+
+        sendEncoding = sendEncoding or os.getenv('WATCHMAN_ENCODING') or 'bser'
+        recvEncoding = recvEncoding or os.getenv('WATCHMAN_ENCODING') or 'bser'
+
+        self.recvCodec = self._parseEncoding(recvEncoding)
+        self.sendCodec = self._parseEncoding(sendEncoding)
+
+    def _parseEncoding(self, enc):
+        if enc == 'bser':
+            if self.useImmutableBser:
+                return ImmutableBserCodec
+            return BserCodec
+        elif enc == 'json':
+            return JsonCodec
+        else:
+            raise WatchmanError('invalid encoding %s' % enc)
+
+    def _hasprop(self, result, name):
+        if self.useImmutableBser:
+            return hasattr(result, name)
+        return name in result
+
+    def _resolvesockname(self):
+        # if invoked via a trigger, watchman will set this env var; we
+        # should use it unless explicitly set otherwise
+        path = os.getenv('WATCHMAN_SOCK')
+        if path:
+            return path
+
+        cmd = ['watchman', '--output-encoding=bser', 'get-sockname']
+        try:
+            p = subprocess.Popen(cmd,
+                                 stdout=subprocess.PIPE,
+                                 stderr=subprocess.PIPE,
+                                 close_fds=os.name != 'nt')
+        except OSError as e:
+            raise WatchmanError('"watchman" executable not in PATH (%s)', e)
+
+        stdout, stderr = p.communicate()
+        exitcode = p.poll()
+
+        if exitcode:
+            raise WatchmanError("watchman exited with code %d" % exitcode)
+
+        result = bser.loads(stdout)
+        if 'error' in result:
+            raise WatchmanError('get-sockname error: %s' % result['error'])
+
+        return result['sockname']
+
+    def _connect(self):
+        """ establish transport connection """
+
+        if self.recvConn:
+            return
+
+        if self.sockpath is None:
+            self.sockpath = self._resolvesockname()
+
+        self.tport = self.transport(self.sockpath, self.timeout)
+        self.sendConn = self.sendCodec(self.tport)
+        self.recvConn = self.recvCodec(self.tport)
+
+    def __del__(self):
+        self.close()
+
+    def close(self):
+        if self.tport:
+            self.tport.close()
+            self.tport = None
+            self.recvConn = None
+            self.sendConn = None
+
+    def receive(self):
+        """ receive the next PDU from the watchman service
+
+        If the client has activated subscriptions or logs then
+        this PDU may be a unilateral PDU sent by the service to
+        inform the client of a log event or subscription change.
+
+        It may also simply be the response portion of a request
+        initiated by query.
+
+        There are clients in production that subscribe and call
+        this in a loop to retrieve all subscription responses,
+        so care should be taken when making changes here.
+        """
+
+        self._connect()
+        result = self.recvConn.receive()
+        if self._hasprop(result, 'error'):
+            raise CommandError(result['error'])
+
+        if self._hasprop(result, 'log'):
+            self.logs.append(result['log'])
+
+        if self._hasprop(result, 'subscription'):
+            sub = result['subscription']
+            if not (sub in self.subs):
+                self.subs[sub] = []
+            self.subs[sub].append(result)
+
+            # also accumulate in {root,sub} keyed store
+            root = os.path.normcase(result['root'])
+            if not root in self.sub_by_root:
+                self.sub_by_root[root] = {}
+            if not sub in self.sub_by_root[root]:
+                self.sub_by_root[root][sub] = []
+            self.sub_by_root[root][sub].append(result)
+
+        return result
+
+    def isUnilateralResponse(self, res):
+        for k in self.unilateral:
+            if k in res:
+                return True
+        return False
+
+    def getLog(self, remove=True):
+        """ Retrieve buffered log data
+
+        If remove is true the data will be removed from the buffer.
+        Otherwise it will be left in the buffer
+        """
+        res = self.logs
+        if remove:
+            self.logs = []
+        return res
+
+    def getSubscription(self, name, remove=True, root=None):
+        """ Retrieve the data associated with a named subscription
+
+        If remove is True (the default), the subscription data is removed
+        from the buffer.  Otherwise the data is returned but left in
+        the buffer.
+
+        Returns None if there is no data associated with `name`
+
+        If root is not None, then only return the subscription
+        data that matches both root and name.  When used in this way,
+        remove processing impacts both the unscoped and scoped stores
+        for the subscription data.
+        """
+
+        if root is not None:
+            if not root in self.sub_by_root:
+                return None
+            if not name in self.sub_by_root[root]:
+                return None
+            sub = self.sub_by_root[root][name]
+            if remove:
+                del self.sub_by_root[root][name]
+                # don't let this grow unbounded
+                if name in self.subs:
+                    del self.subs[name]
+            return sub
+
+        if not (name in self.subs):
+            return None
+        sub = self.subs[name]
+        if remove:
+            del self.subs[name]
+        return sub
+
+    def query(self, *args):
+        """ Send a query to the watchman service and return the response
+
+        This call will block until the response is returned.
+        If any unilateral responses are sent by the service in between
+        the request-response they will be buffered up in the client object
+        and NOT returned via this method.
+        """
+
+        log('calling client.query')
+        self._connect()
+        try:
+            self.sendConn.send(args)
+
+            res = self.receive()
+            while self.isUnilateralResponse(res):
+                res = self.receive()
+
+            return res
+        except CommandError as ex:
+            ex.setCommand(args)
+            raise ex
+
+    def capabilityCheck(self, optional=None, required=None):
+        """ Perform a server capability check """
+        res = self.query('version', {
+            'optional': optional or [],
+            'required': required or []
+        })
+
+        if not self._hasprop(res, 'capabilities'):
+            # Server doesn't support capabilities, so we need to
+            # synthesize the results based on the version
+            capabilities.synthesize(res, optional)
+            if 'error' in res:
+                raise CommandError(res['error'])
+
+        return res
+
+    def setTimeout(self, value):
+        self.recvConn.setTimeout(value)
+        self.sendConn.setTimeout(value)
+
+# no-check-code -- this is a 3rd party library
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/fsmonitor/pywatchman/bser.c	Wed Mar 02 16:25:12 2016 +0000
@@ -0,0 +1,950 @@
+/*
+Copyright (c) 2013-2015, Facebook, Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+ * Neither the name Facebook nor the names of its contributors may be used to
+   endorse or promote products derived from this software without specific
+   prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <Python.h>
+#ifdef _MSC_VER
+#define inline __inline
+#include <stdint.h>
+#endif
+
+/* Return the smallest size int that can store the value */
+#define INT_SIZE(x) (((x) == ((int8_t)x))  ? 1 :    \
+                     ((x) == ((int16_t)x)) ? 2 :    \
+                     ((x) == ((int32_t)x)) ? 4 : 8)
+
+#define BSER_ARRAY     0x00
+#define BSER_OBJECT    0x01
+#define BSER_STRING    0x02
+#define BSER_INT8      0x03
+#define BSER_INT16     0x04
+#define BSER_INT32     0x05
+#define BSER_INT64     0x06
+#define BSER_REAL      0x07
+#define BSER_TRUE      0x08
+#define BSER_FALSE     0x09
+#define BSER_NULL      0x0a
+#define BSER_TEMPLATE  0x0b
+#define BSER_SKIP      0x0c
+
+// An immutable object representation of BSER_OBJECT.
+// Rather than build a hash table, key -> value are obtained
+// by walking the list of keys to determine the offset into
+// the values array.  The assumption is that the number of
+// array elements will be typically small (~6 for the top
+// level query result and typically 3-5 for the file entries)
+// so that the time overhead for this is small compared to
+// using a proper hash table.  Even with this simplistic
+// approach, this is still faster for the mercurial use case
+// as it helps to eliminate creating N other objects to
+// represent the stat information in the hgwatchman extension
+typedef struct {
+  PyObject_HEAD
+  PyObject *keys;   // tuple of field names
+  PyObject *values; // tuple of values
+} bserObject;
+
+static Py_ssize_t bserobj_tuple_length(PyObject *o) {
+  bserObject *obj = (bserObject*)o;
+
+  return PySequence_Length(obj->keys);
+}
+
+static PyObject *bserobj_tuple_item(PyObject *o, Py_ssize_t i) {
+  bserObject *obj = (bserObject*)o;
+
+  return PySequence_GetItem(obj->values, i);
+}
+
+static PySequenceMethods bserobj_sq = {
+  bserobj_tuple_length,      /* sq_length */
+  0,                         /* sq_concat */
+  0,                         /* sq_repeat */
+  bserobj_tuple_item,        /* sq_item */
+  0,                         /* sq_ass_item */
+  0,                         /* sq_contains */
+  0,                         /* sq_inplace_concat */
+  0                          /* sq_inplace_repeat */
+};
+
+static void bserobj_dealloc(PyObject *o) {
+  bserObject *obj = (bserObject*)o;
+
+  Py_CLEAR(obj->keys);
+  Py_CLEAR(obj->values);
+  PyObject_Del(o);
+}
+
+static PyObject *bserobj_getattrro(PyObject *o, PyObject *name) {
+  bserObject *obj = (bserObject*)o;
+  Py_ssize_t i, n;
+  const char *namestr;
+
+  if (PyIndex_Check(name)) {
+    i = PyNumber_AsSsize_t(name, PyExc_IndexError);
+    if (i == -1 && PyErr_Occurred()) {
+      return NULL;
+    }
+    return PySequence_GetItem(obj->values, i);
+  }
+
+  // hack^Wfeature to allow mercurial to use "st_size" to reference "size"
+  namestr = PyString_AsString(name);
+  if (!strncmp(namestr, "st_", 3)) {
+    namestr += 3;
+  }
+
+  n = PyTuple_GET_SIZE(obj->keys);
+  for (i = 0; i < n; i++) {
+    const char *item_name = NULL;
+    PyObject *key = PyTuple_GET_ITEM(obj->keys, i);
+
+    item_name = PyString_AsString(key);
+    if (!strcmp(item_name, namestr)) {
+      return PySequence_GetItem(obj->values, i);
+    }
+  }
+  PyErr_Format(PyExc_AttributeError,
+              "bserobject has no attribute '%.400s'", namestr);
+  return NULL;
+}
+
+static PyMappingMethods bserobj_map = {
+  bserobj_tuple_length,     /* mp_length */
+  bserobj_getattrro,        /* mp_subscript */
+  0                         /* mp_ass_subscript */
+};
+
+PyTypeObject bserObjectType = {
+  PyVarObject_HEAD_INIT(NULL, 0)
+  "bserobj_tuple",           /* tp_name */
+  sizeof(bserObject),        /* tp_basicsize */
+  0,                         /* tp_itemsize */
+  bserobj_dealloc,           /* tp_dealloc */
+  0,                         /* tp_print */
+  0,                         /* tp_getattr */
+  0,                         /* tp_setattr */
+  0,                         /* tp_compare */
+  0,                         /* tp_repr */
+  0,                         /* tp_as_number */
+  &bserobj_sq,               /* tp_as_sequence */
+  &bserobj_map,              /* tp_as_mapping */
+  0,                         /* tp_hash  */
+  0,                         /* tp_call */
+  0,                         /* tp_str */
+  bserobj_getattrro,         /* tp_getattro */
+  0,                         /* tp_setattro */
+  0,                         /* tp_as_buffer */
+  Py_TPFLAGS_DEFAULT,        /* tp_flags */
+  "bserobj tuple",           /* tp_doc */
+  0,                         /* tp_traverse */
+  0,                         /* tp_clear */
+  0,                         /* tp_richcompare */
+  0,                         /* tp_weaklistoffset */
+  0,                         /* tp_iter */
+  0,                         /* tp_iternext */
+  0,                         /* tp_methods */
+  0,                         /* tp_members */
+  0,                         /* tp_getset */
+  0,                         /* tp_base */
+  0,                         /* tp_dict */
+  0,                         /* tp_descr_get */
+  0,                         /* tp_descr_set */
+  0,                         /* tp_dictoffset */
+  0,                         /* tp_init */
+  0,                         /* tp_alloc */
+  0,                         /* tp_new */
+};
+
+
+static PyObject *bser_loads_recursive(const char **ptr, const char *end,
+    int mutable);
+
+static const char bser_true = BSER_TRUE;
+static const char bser_false = BSER_FALSE;
+static const char bser_null = BSER_NULL;
+static const char bser_string_hdr = BSER_STRING;
+static const char bser_array_hdr = BSER_ARRAY;
+static const char bser_object_hdr = BSER_OBJECT;
+
+static inline uint32_t next_power_2(uint32_t n)
+{
+  n |= (n >> 16);
+  n |= (n >> 8);
+  n |= (n >> 4);
+  n |= (n >> 2);
+  n |= (n >> 1);
+  return n + 1;
+}
+
+// A buffer we use for building up the serialized result
+struct bser_buffer {
+  char *buf;
+  int wpos, allocd;
+};
+typedef struct bser_buffer bser_t;
+
+static int bser_append(bser_t *bser, const char *data, uint32_t len)
+{
+  int newlen = next_power_2(bser->wpos + len);
+  if (newlen > bser->allocd) {
+    char *nbuf = realloc(bser->buf, newlen);
+    if (!nbuf) {
+      return 0;
+    }
+
+    bser->buf = nbuf;
+    bser->allocd = newlen;
+  }
+
+  memcpy(bser->buf + bser->wpos, data, len);
+  bser->wpos += len;
+  return 1;
+}
+
+static int bser_init(bser_t *bser)
+{
+  bser->allocd = 8192;
+  bser->wpos = 0;
+  bser->buf = malloc(bser->allocd);
+
+  if (!bser->buf) {
+    return 0;
+  }
+
+  // Leave room for the serialization header, which includes
+  // our overall length.  To make things simpler, we'll use an
+  // int32 for the header
+#define EMPTY_HEADER "\x00\x01\x05\x00\x00\x00\x00"
+  bser_append(bser, EMPTY_HEADER, sizeof(EMPTY_HEADER)-1);
+
+  return 1;
+}
+
+static void bser_dtor(bser_t *bser)
+{
+  free(bser->buf);
+  bser->buf = NULL;
+}
+
+static int bser_long(bser_t *bser, int64_t val)
+{
+  int8_t i8;
+  int16_t i16;
+  int32_t i32;
+  int64_t i64;
+  char sz;
+  int size = INT_SIZE(val);
+  char *iptr;
+
+  switch (size) {
+    case 1:
+      sz = BSER_INT8;
+      i8 = (int8_t)val;
+      iptr = (char*)&i8;
+      break;
+    case 2:
+      sz = BSER_INT16;
+      i16 = (int16_t)val;
+      iptr = (char*)&i16;
+      break;
+    case 4:
+      sz = BSER_INT32;
+      i32 = (int32_t)val;
+      iptr = (char*)&i32;
+      break;
+    case 8:
+      sz = BSER_INT64;
+      i64 = (int64_t)val;
+      iptr = (char*)&i64;
+      break;
+    default:
+      PyErr_SetString(PyExc_RuntimeError,
+          "Cannot represent this long value!?");
+      return 0;
+  }
+
+  if (!bser_append(bser, &sz, sizeof(sz))) {
+    return 0;
+  }
+
+  return bser_append(bser, iptr, size);
+}
+
+static int bser_string(bser_t *bser, PyObject *sval)
+{
+  char *buf = NULL;
+  Py_ssize_t len;
+  int res;
+  PyObject *utf = NULL;
+
+  if (PyUnicode_Check(sval)) {
+    utf = PyUnicode_AsEncodedString(sval, "utf-8", "ignore");
+    sval = utf;
+  }
+
+  res = PyString_AsStringAndSize(sval, &buf, &len);
+  if (res == -1) {
+    res = 0;
+    goto out;
+  }
+
+  if (!bser_append(bser, &bser_string_hdr, sizeof(bser_string_hdr))) {
+    res = 0;
+    goto out;
+  }
+
+  if (!bser_long(bser, len)) {
+    res = 0;
+    goto out;
+  }
+
+  if (len > UINT32_MAX) {
+    PyErr_Format(PyExc_ValueError, "string too big");
+    res = 0;
+    goto out;
+  }
+
+  res = bser_append(bser, buf, (uint32_t)len);
+
+out:
+  if (utf) {
+    Py_DECREF(utf);
+  }
+
+  return res;
+}
+
+static int bser_recursive(bser_t *bser, PyObject *val)
+{
+  if (PyBool_Check(val)) {
+    if (val == Py_True) {
+      return bser_append(bser, &bser_true, sizeof(bser_true));
+    }
+    return bser_append(bser, &bser_false, sizeof(bser_false));
+  }
+
+  if (val == Py_None) {
+    return bser_append(bser, &bser_null, sizeof(bser_null));
+  }
+
+  if (PyInt_Check(val)) {
+    return bser_long(bser, PyInt_AS_LONG(val));
+  }
+
+  if (PyLong_Check(val)) {
+    return bser_long(bser, PyLong_AsLongLong(val));
+  }
+
+  if (PyString_Check(val) || PyUnicode_Check(val)) {
+    return bser_string(bser, val);
+  }
+
+
+  if (PyFloat_Check(val)) {
+    double dval = PyFloat_AS_DOUBLE(val);
+    char sz = BSER_REAL;
+
+    if (!bser_append(bser, &sz, sizeof(sz))) {
+      return 0;
+    }
+
+    return bser_append(bser, (char*)&dval, sizeof(dval));
+  }
+
+  if (PyList_Check(val)) {
+    Py_ssize_t i, len = PyList_GET_SIZE(val);
+
+    if (!bser_append(bser, &bser_array_hdr, sizeof(bser_array_hdr))) {
+      return 0;
+    }
+
+    if (!bser_long(bser, len)) {
+      return 0;
+    }
+
+    for (i = 0; i < len; i++) {
+      PyObject *ele = PyList_GET_ITEM(val, i);
+
+      if (!bser_recursive(bser, ele)) {
+        return 0;
+      }
+    }
+
+    return 1;
+  }
+
+  if (PyTuple_Check(val)) {
+    Py_ssize_t i, len = PyTuple_GET_SIZE(val);
+
+    if (!bser_append(bser, &bser_array_hdr, sizeof(bser_array_hdr))) {
+      return 0;
+    }
+
+    if (!bser_long(bser, len)) {
+      return 0;
+    }
+
+    for (i = 0; i < len; i++) {
+      PyObject *ele = PyTuple_GET_ITEM(val, i);
+
+      if (!bser_recursive(bser, ele)) {
+        return 0;
+      }
+    }
+
+    return 1;
+  }
+
+  if (PyMapping_Check(val)) {
+    Py_ssize_t len = PyMapping_Length(val);
+    Py_ssize_t pos = 0;
+    PyObject *key, *ele;
+
+    if (!bser_append(bser, &bser_object_hdr, sizeof(bser_object_hdr))) {
+      return 0;
+    }
+
+    if (!bser_long(bser, len)) {
+      return 0;
+    }
+
+    while (PyDict_Next(val, &pos, &key, &ele)) {
+      if (!bser_string(bser, key)) {
+        return 0;
+      }
+      if (!bser_recursive(bser, ele)) {
+        return 0;
+      }
+    }
+
+    return 1;
+  }
+
+  PyErr_SetString(PyExc_ValueError, "Unsupported value type");
+  return 0;
+}
+
+static PyObject *bser_dumps(PyObject *self, PyObject *args)
+{
+  PyObject *val = NULL, *res;
+  bser_t bser;
+  uint32_t len;
+
+  if (!PyArg_ParseTuple(args, "O", &val)) {
+    return NULL;
+  }
+
+  if (!bser_init(&bser)) {
+    return PyErr_NoMemory();
+  }
+
+  if (!bser_recursive(&bser, val)) {
+    bser_dtor(&bser);
+    if (errno == ENOMEM) {
+      return PyErr_NoMemory();
+    }
+    // otherwise, we've already set the error to something reasonable
+    return NULL;
+  }
+
+  // Now fill in the overall length
+  len = bser.wpos - (sizeof(EMPTY_HEADER) - 1);
+  memcpy(bser.buf + 3, &len, sizeof(len));
+
+  res = PyString_FromStringAndSize(bser.buf, bser.wpos);
+  bser_dtor(&bser);
+
+  return res;
+}
+
+int bunser_int(const char **ptr, const char *end, int64_t *val)
+{
+  int needed;
+  const char *buf = *ptr;
+  int8_t i8;
+  int16_t i16;
+  int32_t i32;
+  int64_t i64;
+
+  switch (buf[0]) {
+    case BSER_INT8:
+      needed = 2;
+      break;
+    case BSER_INT16:
+      needed = 3;
+      break;
+    case BSER_INT32:
+      needed = 5;
+      break;
+    case BSER_INT64:
+      needed = 9;
+      break;
+    default:
+      PyErr_Format(PyExc_ValueError,
+          "invalid bser int encoding 0x%02x", buf[0]);
+      return 0;
+  }
+  if (end - buf < needed) {
+    PyErr_SetString(PyExc_ValueError, "input buffer to small for int encoding");
+    return 0;
+  }
+  *ptr = buf + needed;
+  switch (buf[0]) {
+    case BSER_INT8:
+      memcpy(&i8, buf + 1, sizeof(i8));
+      *val = i8;
+      return 1;
+    case BSER_INT16:
+      memcpy(&i16, buf + 1, sizeof(i16));
+      *val = i16;
+      return 1;
+    case BSER_INT32:
+      memcpy(&i32, buf + 1, sizeof(i32));
+      *val = i32;
+      return 1;
+    case BSER_INT64:
+      memcpy(&i64, buf + 1, sizeof(i64));
+      *val = i64;
+      return 1;
+    default:
+      return 0;
+  }
+}
+
+static int bunser_string(const char **ptr, const char *end,
+    const char **start, int64_t *len)
+{
+  const char *buf = *ptr;
+
+  // skip string marker
+  buf++;
+  if (!bunser_int(&buf, end, len)) {
+    return 0;
+  }
+
+  if (buf + *len > end) {
+    PyErr_Format(PyExc_ValueError, "invalid string length in bser data");
+    return 0;
+  }
+
+  *ptr = buf + *len;
+  *start = buf;
+  return 1;
+}
+
+static PyObject *bunser_array(const char **ptr, const char *end, int mutable)
+{
+  const char *buf = *ptr;
+  int64_t nitems, i;
+  PyObject *res;
+
+  // skip array header
+  buf++;
+  if (!bunser_int(&buf, end, &nitems)) {
+    return 0;
+  }
+  *ptr = buf;
+
+  if (nitems > LONG_MAX) {
+    PyErr_Format(PyExc_ValueError, "too many items for python array");
+    return NULL;
+  }
+
+  if (mutable) {
+    res = PyList_New((Py_ssize_t)nitems);
+  } else {
+    res = PyTuple_New((Py_ssize_t)nitems);
+  }
+
+  for (i = 0; i < nitems; i++) {
+    PyObject *ele = bser_loads_recursive(ptr, end, mutable);
+
+    if (!ele) {
+      Py_DECREF(res);
+      return NULL;
+    }
+
+    if (mutable) {
+      PyList_SET_ITEM(res, i, ele);
+    } else {
+      PyTuple_SET_ITEM(res, i, ele);
+    }
+    // DECREF(ele) not required as SET_ITEM steals the ref
+  }
+
+  return res;
+}
+
+static PyObject *bunser_object(const char **ptr, const char *end,
+    int mutable)
+{
+  const char *buf = *ptr;
+  int64_t nitems, i;
+  PyObject *res;
+  bserObject *obj;
+
+  // skip array header
+  buf++;
+  if (!bunser_int(&buf, end, &nitems)) {
+    return 0;
+  }
+  *ptr = buf;
+
+  if (mutable) {
+    res = PyDict_New();
+  } else {
+    obj = PyObject_New(bserObject, &bserObjectType);
+    obj->keys = PyTuple_New((Py_ssize_t)nitems);
+    obj->values = PyTuple_New((Py_ssize_t)nitems);
+    res = (PyObject*)obj;
+  }
+
+  for (i = 0; i < nitems; i++) {
+    const char *keystr;
+    int64_t keylen;
+    PyObject *key;
+    PyObject *ele;
+
+    if (!bunser_string(ptr, end, &keystr, &keylen)) {
+      Py_DECREF(res);
+      return NULL;
+    }
+
+    if (keylen > LONG_MAX) {
+      PyErr_Format(PyExc_ValueError, "string too big for python");
+      Py_DECREF(res);
+      return NULL;
+    }
+
+    key = PyString_FromStringAndSize(keystr, (Py_ssize_t)keylen);
+    if (!key) {
+      Py_DECREF(res);
+      return NULL;
+    }
+
+    ele = bser_loads_recursive(ptr, end, mutable);
+
+    if (!ele) {
+      Py_DECREF(key);
+      Py_DECREF(res);
+      return NULL;
+    }
+
+    if (mutable) {
+      PyDict_SetItem(res, key, ele);
+      Py_DECREF(key);
+      Py_DECREF(ele);
+    } else {
+      /* PyTuple_SET_ITEM steals ele, key */
+      PyTuple_SET_ITEM(obj->values, i, ele);
+      PyTuple_SET_ITEM(obj->keys, i, key);
+    }
+  }
+
+  return res;
+}
+
+static PyObject *bunser_template(const char **ptr, const char *end,
+    int mutable)
+{
+  const char *buf = *ptr;
+  int64_t nitems, i;
+  PyObject *arrval;
+  PyObject *keys;
+  Py_ssize_t numkeys, keyidx;
+
+  if (buf[1] != BSER_ARRAY) {
+    PyErr_Format(PyExc_ValueError, "Expect ARRAY to follow TEMPLATE");
+    return NULL;
+  }
+
+  // skip header
+  buf++;
+  *ptr = buf;
+
+  // Load template keys
+  keys = bunser_array(ptr, end, mutable);
+  if (!keys) {
+    return NULL;
+  }
+
+  numkeys = PySequence_Length(keys);
+
+  // Load number of array elements
+  if (!bunser_int(ptr, end, &nitems)) {
+    Py_DECREF(keys);
+    return 0;
+  }
+
+  if (nitems > LONG_MAX) {
+    PyErr_Format(PyExc_ValueError, "Too many items for python");
+    Py_DECREF(keys);
+    return NULL;
+  }
+
+  arrval = PyList_New((Py_ssize_t)nitems);
+  if (!arrval) {
+    Py_DECREF(keys);
+    return NULL;
+  }
+
+  for (i = 0; i < nitems; i++) {
+    PyObject *dict = NULL;
+    bserObject *obj = NULL;
+
+    if (mutable) {
+      dict = PyDict_New();
+    } else {
+      obj = PyObject_New(bserObject, &bserObjectType);
+      if (obj) {
+        obj->keys = keys;
+        Py_INCREF(obj->keys);
+        obj->values = PyTuple_New(numkeys);
+      }
+      dict = (PyObject*)obj;
+    }
+    if (!dict) {
+fail:
+      Py_DECREF(keys);
+      Py_DECREF(arrval);
+      return NULL;
+    }
+
+    for (keyidx = 0; keyidx < numkeys; keyidx++) {
+      PyObject *key;
+      PyObject *ele;
+
+      if (**ptr == BSER_SKIP) {
+        *ptr = *ptr + 1;
+        ele = Py_None;
+        Py_INCREF(ele);
+      } else {
+        ele = bser_loads_recursive(ptr, end, mutable);
+      }
+
+      if (!ele) {
+        goto fail;
+      }
+
+      if (mutable) {
+        key = PyList_GET_ITEM(keys, keyidx);
+        PyDict_SetItem(dict, key, ele);
+        Py_DECREF(ele);
+      } else {
+        PyTuple_SET_ITEM(obj->values, keyidx, ele);
+        // DECREF(ele) not required as SET_ITEM steals the ref
+      }
+    }
+
+    PyList_SET_ITEM(arrval, i, dict);
+    // DECREF(obj) not required as SET_ITEM steals the ref
+  }
+
+  Py_DECREF(keys);
+
+  return arrval;
+}
+
+static PyObject *bser_loads_recursive(const char **ptr, const char *end,
+    int mutable)
+{
+  const char *buf = *ptr;
+
+  switch (buf[0]) {
+    case BSER_INT8:
+    case BSER_INT16:
+    case BSER_INT32:
+    case BSER_INT64:
+      {
+        int64_t ival;
+        if (!bunser_int(ptr, end, &ival)) {
+          return NULL;
+        }
+        if (ival < LONG_MIN || ival > LONG_MAX) {
+          return PyLong_FromLongLong(ival);
+        }
+        return PyInt_FromSsize_t(Py_SAFE_DOWNCAST(ival, int64_t, Py_ssize_t));
+      }
+
+    case BSER_REAL:
+      {
+        double dval;
+        memcpy(&dval, buf + 1, sizeof(dval));
+        *ptr = buf + 1 + sizeof(double);
+        return PyFloat_FromDouble(dval);
+      }
+
+    case BSER_TRUE:
+      *ptr = buf + 1;
+      Py_INCREF(Py_True);
+      return Py_True;
+
+    case BSER_FALSE:
+      *ptr = buf + 1;
+      Py_INCREF(Py_False);
+      return Py_False;
+
+    case BSER_NULL:
+      *ptr = buf + 1;
+      Py_INCREF(Py_None);
+      return Py_None;
+
+    case BSER_STRING:
+      {
+        const char *start;
+        int64_t len;
+
+        if (!bunser_string(ptr, end, &start, &len)) {
+          return NULL;
+        }
+
+        if (len > LONG_MAX) {
+          PyErr_Format(PyExc_ValueError, "string too long for python");
+          return NULL;
+        }
+
+        return PyString_FromStringAndSize(start, (long)len);
+      }
+
+    case BSER_ARRAY:
+      return bunser_array(ptr, end, mutable);
+
+    case BSER_OBJECT:
+      return bunser_object(ptr, end, mutable);
+
+    case BSER_TEMPLATE:
+      return bunser_template(ptr, end, mutable);
+
+    default:
+      PyErr_Format(PyExc_ValueError, "unhandled bser opcode 0x%02x", buf[0]);
+  }
+
+  return NULL;
+}
+
+// Expected use case is to read a packet from the socket and
+// then call bser.pdu_len on the packet.  It returns the total
+// length of the entire response that the peer is sending,
+// including the bytes already received.  This allows the client
+// to compute the data size it needs to read before it can
+// decode the data
+static PyObject *bser_pdu_len(PyObject *self, PyObject *args)
+{
+  const char *start = NULL;
+  const char *data = NULL;
+  int datalen = 0;
+  const char *end;
+  int64_t expected_len, total_len;
+
+  if (!PyArg_ParseTuple(args, "s#", &start, &datalen)) {
+    return NULL;
+  }
+  data = start;
+  end = data + datalen;
+
+  // Validate the header and length
+  if (memcmp(data, EMPTY_HEADER, 2) != 0) {
+    PyErr_SetString(PyExc_ValueError, "invalid bser header");
+    return NULL;
+  }
+
+  data += 2;
+
+  // Expect an integer telling us how big the rest of the data
+  // should be
+  if (!bunser_int(&data, end, &expected_len)) {
+    return NULL;
+  }
+
+  total_len = expected_len + (data - start);
+  if (total_len > LONG_MAX) {
+    return PyLong_FromLongLong(total_len);
+  }
+  return PyInt_FromLong((long)total_len);
+}
+
+static PyObject *bser_loads(PyObject *self, PyObject *args)
+{
+  const char *data = NULL;
+  int datalen = 0;
+  const char *end;
+  int64_t expected_len;
+  int mutable = 1;
+  PyObject *mutable_obj = NULL;
+
+  if (!PyArg_ParseTuple(args, "s#|O:loads", &data, &datalen, &mutable_obj)) {
+    return NULL;
+  }
+  if (mutable_obj) {
+    mutable = PyObject_IsTrue(mutable_obj) > 0 ? 1 : 0;
+  }
+
+  end = data + datalen;
+
+  // Validate the header and length
+  if (memcmp(data, EMPTY_HEADER, 2) != 0) {
+    PyErr_SetString(PyExc_ValueError, "invalid bser header");
+    return NULL;
+  }
+
+  data += 2;
+
+  // Expect an integer telling us how big the rest of the data
+  // should be
+  if (!bunser_int(&data, end, &expected_len)) {
+    return NULL;
+  }
+
+  // Verify
+  if (expected_len + data != end) {
+    PyErr_SetString(PyExc_ValueError, "bser data len != header len");
+    return NULL;
+  }
+
+  return bser_loads_recursive(&data, end, mutable);
+}
+
+static PyMethodDef bser_methods[] = {
+  {"loads",  bser_loads, METH_VARARGS, "Deserialize string."},
+  {"pdu_len", bser_pdu_len, METH_VARARGS, "Extract PDU length."},
+  {"dumps",  bser_dumps, METH_VARARGS, "Serialize string."},
+  {NULL, NULL, 0, NULL}
+};
+
+PyMODINIT_FUNC initbser(void)
+{
+  (void)Py_InitModule("bser", bser_methods);
+  PyType_Ready(&bserObjectType);
+}
+
+/* vim:ts=2:sw=2:et:
+ */
+
+// no-check-code -- this is a 3rd party library
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/fsmonitor/pywatchman/capabilities.py	Wed Mar 02 16:25:12 2016 +0000
@@ -0,0 +1,69 @@
+# Copyright 2015 Facebook, Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+#  * Redistributions of source code must retain the above copyright notice,
+#    this list of conditions and the following disclaimer.
+#
+#  * Redistributions in binary form must reproduce the above copyright notice,
+#    this list of conditions and the following disclaimer in the documentation
+#    and/or other materials provided with the distribution.
+#
+#  * Neither the name Facebook nor the names of its contributors may be used to
+#    endorse or promote products derived from this software without specific
+#    prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import re
+
+def parse_version(vstr):
+    res = 0
+    for n in vstr.split('.'):
+        res = res * 1000
+        res = res + int(n)
+    return res
+
+cap_versions = {
+    "cmd-watch-del-all": "3.1.1",
+    "cmd-watch-project": "3.1",
+    "relative_root": "3.3",
+    "term-dirname": "3.1",
+    "term-idirname": "3.1",
+    "wildmatch": "3.7",
+}
+
+def check(version, name):
+    if name in cap_versions:
+        return version >= parse_version(cap_versions[name])
+    return False
+
+def synthesize(vers, opts):
+    """ Synthesize a capability enabled version response
+        This is a very limited emulation for relatively recent feature sets
+    """
+    parsed_version = parse_version(vers['version'])
+    vers['capabilities'] = {}
+    for name in opts['optional']:
+        vers['capabilities'][name] = check(parsed_version, name)
+    failed = False
+    for name in opts['required']:
+        have = check(parsed_version, name)
+        vers['capabilities'][name] = have
+        if not have:
+            vers['error'] = 'client required capability `' + name + \
+                            '` is not supported by this server'
+    return vers
+
+# no-check-code -- this is a 3rd party library
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hgext/fsmonitor/pywatchman/pybser.py	Wed Mar 02 16:25:12 2016 +0000
@@ -0,0 +1,359 @@
+# Copyright 2015 Facebook, Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+#  * Redistributions of source code must retain the above copyright notice,
+#    this list of conditions and the following disclaimer.
+#
+#  * Redistributions in binary form must reproduce the above copyright notice,
+#    this list of conditions and the following disclaimer in the documentation
+#    and/or other materials provided with the distribution.
+#
+#  * Neither the name Facebook nor the names of its contributors may be used to
+#    endorse or promote products derived from this software without specific
+#    prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import collections
+import ctypes
+import struct
+import sys
+
+BSER_ARRAY = '\x00'
+BSER_OBJECT = '\x01'
+BSER_STRING = '\x02'
+BSER_INT8 = '\x03'
+BSER_INT16 = '\x04'
+BSER_INT32 = '\x05'
+BSER_INT64 = '\x06'
+BSER_REAL = '\x07'
+BSER_TRUE = '\x08'
+BSER_FALSE = '\x09'
+BSER_NULL = '\x0a'
+BSER_TEMPLATE = '\x0b'
+BSER_SKIP = '\x0c'
+
+# Leave room for the serialization header, which includes
+# our overall length.  To make things simpler, we'll use an
+# int32 for the header
+EMPTY_HEADER = "\x00\x01\x05\x00\x00\x00\x00"
+
+# Python 3 conditional for supporting Python 2's int/long types
+if sys.version_info > (3,):
+    long = int
+
+def _int_size(x):
+    """Return the smallest size int that can store the value"""
+    if -0x80 <= x <= 0x7F:
+        return 1
+    elif -0x8000 <= x <= 0x7FFF:
+        return 2
+    elif -0x80000000 <= x <= 0x7FFFFFFF:
+        return 4
+    elif long(-0x8000000000000000) <= x <= long(0x7FFFFFFFFFFFFFFF):
+        return 8
+    else:
+        raise RuntimeError('Cannot represent value: ' + str(x))
+
+
+class _bser_buffer(object):
+
+    def __init__(self):
+        self.buf = ctypes.create_string_buffer(8192)
+        struct.pack_into(str(len(EMPTY_HEADER)) + 's', self.buf, 0, EMPTY_HEADER)
+        self.wpos = len(EMPTY_HEADER)
+
+    def ensure_size(self, size):
+        while ctypes.sizeof(self.buf) - self.wpos < size:
+            ctypes.resize(self.buf, ctypes.sizeof(self.buf) * 2)
+
+    def append_long(self, val):
+        size = _int_size(val)
+        to_write = size + 1
+        self.ensure_size(to_write)
+        if size == 1:
+            struct.pack_into('=cb', self.buf, self.wpos, BSER_INT8, val)
+        elif size == 2:
+            struct.pack_into('=ch', self.buf, self.wpos, BSER_INT16, val)
+        elif size == 4:
+            struct.pack_into('=ci', self.buf, self.wpos, BSER_INT32, val)
+        elif size == 8:
+            struct.pack_into('=cq', self.buf, self.wpos, BSER_INT64, val)
+        else:
+            raise RuntimeError('Cannot represent this long value')
+        self.wpos += to_write
+
+
+    def append_string(self, s):
+        if isinstance(s, unicode):
+            s = s.encode('utf-8')
+        s_len = len(s)
+        size = _int_size(s_len)
+        to_write = 2 + size + s_len
+        self.ensure_size(to_write)
+        if size == 1:
+            struct.pack_into('=ccb' + str(s_len) + 's', self.buf, self.wpos, BSER_STRING, BSER_INT8, s_len, s)
+        elif size == 2:
+            struct.pack_into('=cch' + str(s_len) + 's', self.buf, self.wpos, BSER_STRING, BSER_INT16, s_len, s)
+        elif size == 4:
+            struct.pack_into('=cci' + str(s_len) + 's', self.buf, self.wpos, BSER_STRING, BSER_INT32, s_len, s)
+        elif size == 8:
+            struct.pack_into('=ccq' + str(s_len) + 's', self.buf, self.wpos, BSER_STRING, BSER_INT64, s_len, s)
+        else:
+            raise RuntimeError('Cannot represent this string value')
+        self.wpos += to_write
+
+
+    def append_recursive(self, val):
+        if isinstance(val, bool):
+            needed = 1
+            self.ensure_size(needed)
+            if val:
+                to_encode = BSER_TRUE
+            else:
+                to_encode = BSER_FALSE
+            struct.pack_into('=c', self.buf, self.wpos, to_encode)
+            self.wpos += needed
+        elif val is None:
+            needed = 1
+            self.ensure_size(needed)
+            struct.pack_into('=c', self.buf, self.wpos, BSER_NULL)
+            self.wpos += needed
+        elif isinstance(val, (int, long)):
+            self.append_long(val)
+        elif isinstance(val, (str, unicode)):
+            self.append_string(val)
+        elif isinstance(val, float):
+            needed = 9
+            self.ensure_size(needed)
+            struct.pack_into('=cd', self.buf, self.wpos, BSER_REAL, val)
+            self.wpos += needed
+        elif isinstance(val, collections.Mapping) and isinstance(val, collections.Sized):
+            val_len = len(val)
+            size = _int_size(val_len)
+            needed = 2 + size
+            self.ensure_size(needed)
+            if size == 1:
+                struct.pack_into('=ccb', self.buf, self.wpos, BSER_OBJECT, BSER_INT8, val_len)
+            elif size == 2:
+                struct.pack_into('=cch', self.buf, self.wpos, BSER_OBJECT, BSER_INT16, val_len)
+            elif size == 4:
+                struct.pack_into('=cci', self.buf, self.wpos, BSER_OBJECT, BSER_INT32, val_len)
+            elif size == 8:
+                struct.pack_into('=ccq', self.buf, self.wpos, BSER_OBJECT, BSER_INT64, val_len)
+            else:
+                raise RuntimeError('Cannot represent this mapping value')
+            self.wpos += needed
+            for k, v in val.iteritems():
+                self.append_string(k)
+                self.append_recursive(v)
+        elif isinstance(val, collections.Iterable) and isinstance(val, collections.Sized):
+            val_len = len(val)
+            size = _int_size(val_len)
+            needed = 2 + size
+            self.ensure_size(needed)
+            if size == 1:
+                struct.pack_into('=ccb', self.buf, self.wpos, BSER_ARRAY, BSER_INT8, val_len)
+            elif size == 2:
+                struct.pack_into('=cch', self.buf, self.wpos, BSER_ARRAY, BSER_INT16, val_len)
+            elif size == 4:
+                struct.pack_into('=cci', self.buf, self.wpos, BSER_ARRAY, BSER_INT32, val_len)
+            elif size == 8:
+                struct.pack_into('=ccq', self.buf, self.wpos, BSER_ARRAY, BSER_INT64, val_len)
+            else:
+                raise RuntimeError('Cannot represent this sequence value')
+            self.wpos += needed
+            for v in val:
+                self.append_recursive(v)
+        else:
+            raise RuntimeError('Cannot represent unknown value type')
+
+
+def dumps(obj):
+    bser_buf = _bser_buffer()
+    bser_buf.append_recursive(obj)
+    # Now fill in the overall length
+    obj_len = bser_buf.wpos - len(EMPTY_HEADER)
+    struct.pack_into('=i', bser_buf.buf, 3, obj_len)
+    return bser_buf.buf.raw[:bser_buf.wpos]
+
+
+def _bunser_int(buf, pos):
+    try:
+        int_type = buf[pos]
+    except IndexError:
+        raise ValueError('Invalid bser int encoding, pos out of range')
+    if int_type == BSER_INT8:
+        needed = 2
+        fmt = '=b'
+    elif int_type == BSER_INT16:
+        needed = 3
+        fmt = '=h'
+    elif int_type == BSER_INT32:
+        needed = 5
+        fmt = '=i'
+    elif int_type == BSER_INT64:
+        needed = 9
+        fmt = '=q'
+    else:
+        raise ValueError('Invalid bser int encoding 0x%02x' % int(int_type))
+    int_val = struct.unpack_from(fmt, buf, pos + 1)[0]
+    return (int_val, pos + needed)
+
+
+def _bunser_string(buf, pos):
+    str_len, pos = _bunser_int(buf, pos + 1)
+    str_val = struct.unpack_from(str(str_len) + 's', buf, pos)[0]
+    return (str_val, pos + str_len)
+
+
+def _bunser_array(buf, pos, mutable=True):
+    arr_len, pos = _bunser_int(buf, pos + 1)
+    arr = []
+    for i in range(arr_len):
+        arr_item, pos = _bser_loads_recursive(buf, pos, mutable)
+        arr.append(arr_item)
+
+    if not mutable:
+      arr = tuple(arr)
+
+    return arr, pos
+
+
+# This is a quack-alike with the bserObjectType in bser.c
+# It provides by getattr accessors and getitem for both index
+# and name.
+class _BunserDict(object):
+    __slots__ = ('_keys', '_values')
+
+    def __init__(self, keys, values):
+        self._keys = keys
+        self._values = values
+
+    def __getattr__(self, name):
+        return self.__getitem__(name)
+
+    def __getitem__(self, key):
+        if isinstance(key, (int, long)):
+            return self._values[key]
+        elif key.startswith('st_'):
+            # hack^Wfeature to allow mercurial to use "st_size" to
+            # reference "size"
+            key = key[3:]
+        try:
+            return self._values[self._keys.index(key)]
+        except ValueError as ex:
+            raise KeyError('_BunserDict has no key %s' % key)
+
+    def __len__(self):
+        return len(self._keys)
+
+def _bunser_object(buf, pos, mutable=True):
+    obj_len, pos = _bunser_int(buf, pos + 1)
+    if mutable:
+        obj = {}
+    else:
+        keys = []
+        vals = []
+
+    for i in range(obj_len):
+        key, pos = _bunser_string(buf, pos)
+        val, pos = _bser_loads_recursive(buf, pos, mutable)
+        if mutable:
+            obj[key] = val
+        else:
+            keys.append(key)
+            vals.append(val)
+
+    if not mutable:
+        obj = _BunserDict(keys, vals)
+
+    return obj, pos
+
+
+def _bunser_template(buf, pos, mutable=True):
+    if buf[pos + 1] != BSER_ARRAY:
+        raise RuntimeError('Expect ARRAY to follow TEMPLATE')
+    keys, pos = _bunser_array(buf, pos + 1)
+    nitems, pos = _bunser_int(buf, pos)
+    arr = []
+    for i in range(nitems):
+        if mutable:
+            obj = {}
+        else:
+            vals = []
+
+        for keyidx in range(len(keys)):
+            if buf[pos] == BSER_SKIP:
+                pos += 1
+                ele = None
+            else:
+                ele, pos = _bser_loads_recursive(buf, pos, mutable)
+
+            if mutable:
+                key = keys[keyidx]
+                obj[key] = ele
+            else:
+                vals.append(ele)
+
+        if not mutable:
+            obj = _BunserDict(keys, vals)
+
+        arr.append(obj)
+    return arr, pos
+
+
+def _bser_loads_recursive(buf, pos, mutable=True):
+    val_type = buf[pos]
+    if (val_type == BSER_INT8 or val_type == BSER_INT16 or
+        val_type == BSER_INT32 or val_type == BSER_INT64):
+        return _bunser_int(buf, pos)
+    elif val_type == BSER_REAL:
+        val = struct.unpack_from('=d', buf, pos + 1)[0]
+        return (val, pos + 9)
+    elif val_type == BSER_TRUE:
+        return (True, pos + 1)
+    elif val_type == BSER_FALSE:
+        return (False, pos + 1)
+    elif val_type == BSER_NULL:
+        return (None, pos + 1)
+    elif val_type == BSER_STRING:
+        return _bunser_string(buf, pos)
+    elif val_type == BSER_ARRAY:
+        return _bunser_array(buf, pos, mutable)
+    elif val_type == BSER_OBJECT:
+        return _bunser_object(buf, pos, mutable)
+    elif val_type == BSER_TEMPLATE:
+        return _bunser_template(buf, pos, mutable)
+    else:
+        raise RuntimeError('unhandled bser opcode 0x%02x' % (val_type,))
+
+
+def pdu_len(buf):
+    if buf[0:2] != EMPTY_HEADER[0:2]:
+        raise RuntimeError('Invalid BSER header')
+    expected_len, pos = _bunser_int(buf, 2)
+    return expected_len + pos
+
+
+def loads(buf, mutable=True):
+    if buf[0:2] != EMPTY_HEADER[0:2]:
+        raise RuntimeError('Invalid BSER header')
+    expected_len, pos = _bunser_int(buf, 2)
+    if len(buf) != expected_len + pos:
+        raise RuntimeError('bser data len != header len')
+    return _bser_loads_recursive(buf, pos, mutable)[0]
+
+# no-check-code -- this is a 3rd party library
--- a/setup.py	Tue Jan 12 04:45:29 2016 +0000
+++ b/setup.py	Wed Mar 02 16:25:12 2016 +0000
@@ -532,6 +532,8 @@
     Extension('mercurial.osutil', ['mercurial/osutil.c'],
               extra_link_args=osutil_ldflags,
               depends=common_depends),
+    Extension('hgext.fsmonitor.pywatchman.bser',
+              ['hgext/fsmonitor/pywatchman/bser.c']),
     ]

 try:
--- a/tests/test-check-code.t	Tue Jan 12 04:45:29 2016 +0000
+++ b/tests/test-check-code.t	Wed Mar 02 16:25:12 2016 +0000
@@ -8,6 +8,10 @@

   $ hg locate | sed 's-\\-/-g' |
   >   xargs "$check_code" --warnings --per-file=0 || false
+  Skipping hgext/fsmonitor/pywatchman/__init__.py it has no-che?k-code (glob)
+  Skipping hgext/fsmonitor/pywatchman/bser.c it has no-che?k-code (glob)
+  Skipping hgext/fsmonitor/pywatchman/capabilities.py it has no-che?k-code (glob)
+  Skipping hgext/fsmonitor/pywatchman/pybser.py it has no-che?k-code (glob)
   Skipping i18n/polib.py it has no-che?k-code (glob)
   Skipping mercurial/httpclient/__init__.py it has no-che?k-code (glob)
   Skipping mercurial/httpclient/_readers.py it has no-che?k-code (glob)
--- a/tests/test-check-py3-compat.t	Tue Jan 12 04:45:29 2016 +0000
+++ b/tests/test-check-py3-compat.t	Wed Mar 02 16:25:12 2016 +0000
@@ -25,6 +25,10 @@
   hgext/extdiff.py not using absolute_import
   hgext/factotum.py not using absolute_import
   hgext/fetch.py not using absolute_import
+  hgext/fsmonitor/pywatchman/__init__.py not using absolute_import
+  hgext/fsmonitor/pywatchman/__init__.py requires print_function
+  hgext/fsmonitor/pywatchman/capabilities.py not using absolute_import
+  hgext/fsmonitor/pywatchman/pybser.py not using absolute_import
   hgext/gpg.py not using absolute_import
   hgext/graphlog.py not using absolute_import
   hgext/hgcia.py not using absolute_import