annotate setup.py @ 30760:753b9d43ca81

internals: document compression negotiation

As part of adding zstd support to all of the things, we'll need
to teach the wire protocol to support non-zlib compression formats.

This commit documents how we'll implement that.

To understand how we arrived at this proposal, let's look at how
things are done today.

The wire protocol today doesn't have a unified format. Instead,
there is a limited facility for differentiating replies as successful
or not. And, each command essentially defines its own response format.

A significant deficiency in the current protocol is the lack of
payload framing over the SSH transport. In the HTTP transport,
chunked transfer is used and the end of an HTTP response body (and
the end of a Mercurial command response) can be identified by a 0
length chunk. This is how HTTP chunked transfer works. But in the
SSH transport, there is no such framing, at least for certain
responses (notably the response to "getbundle" requests). Clients
can't simply read until end of stream because the socket is
persistent and reused for multiple requests. Clients need to know
when they've encountered the end of a request but there is nothing
simple for them to key off of to detect this. So what happens is
the client must decode the payload (as opposed to being dumb and
forwarding frames/packets). This means the payload itself needs
to support identifying end of stream. In some cases (bundle2), it
also means the payload can encode "error" or "interrupt" events
telling the client to e.g. abort processing. The lack of framing
on the SSH transport and the transfer of its responsibilities to
e.g. bundle2 is a massive layering violation and a wart on the
protocol architecture. It needs to be fixed someday by inventing a
proper framing protocol.

So about compression.

The client transport abstractions have a "_callcompressable()"
API. This API is called to invoke a remote command that will
send a compressible response. The response is essentially a
"streaming" response (no framing data at the Mercurial layer)
that is fed into a decompressor.

On the HTTP transport, the decompressor is zlib and only zlib.
There is currently no mechanism for the client to specify an
alternate compression format. And, clients don't advertise what
compression formats they support or ask the server to send a
specific compression format. Instead, it is assumed that non-error
responses to "compressible" commands are zlib compressed.

On the SSH transport, there is no compression at the Mercurial
protocol layer. Instead, compression must be handled by SSH
itself (e.g. `ssh -C`) or within the payload data (e.g. bundle
compression).

For the HTTP transport, adding new compression formats is pretty
straightforward. Once you know what decompressor to use, you can
stream data into the decompressor until you reach a 0 size HTTP
chunk, at which point you are at end of stream.

So our wire protocol changes for the HTTP transport are pretty
straightforward: the client and server advertise what compression
formats they support and an appropriate compression format is
chosen. We introduce a new HTTP media type to hold compressed
payloads. The header of the payload defines the compression format
being used. Whoever is on the receiving end can sniff the first few
bytes route to an appropriate decompressor.

Support for multiple compression formats is advertised on both
server and client. The server advertises a "compression" capability
saying which compression formats it supports and in what order they
are preferred. Clients advertise their support for multiple
compression formats and media types via the introduced "X-HgProto"
request header.

Strictly speaking, servers don't need to advertise which compression
formats they support. But doing so allows clients to fail fast if
they don't support any of the formats the server does. This is useful
in situations like sending bundles, where the client may have to
perform expensive computation before sending data to the server.

Rather than simply advertise a list of supported compression formats,
we introduce an additional "httpmediatype" server capability
advertising which media types the server supports. This means servers
are explicit about what formats they exchange. IMO, this is superior
to inferring support from other capabilities (like "compression").

By advertising compression support on each request in the "X-HgProto"
header and media type and direction at the server level, we are able
to gradually transition existing commands/responses to the new media
type and possibly compression. Contrast with the old world, where we
only supported a single media type and the use of compression was
built-in to the semantics of the command on both client and server.
In the new world, if "application/mercurial-0.2" is supported,
compression is supported. It's that simple.

It's worth noting that we explicitly don't use "Accept,"
"Accept-Encoding," "Content-Encoding," or "Transfer-Encoding" for
content negotiation and compression. People knowledgeable of the HTTP
specifications will say that we should use these because that's
what they are designed to be used for. They have a point and I
sympathize with the argument. Earlier versions of this commit even
defined supported media types in the "Accept" header. However, my
years of experience rolling out services leveraging HTTP has taught
me to not trust the HTTP layer, especially if you are going outside
the normal spec (such as using a custom "Content-Encoding" value to
represent zstd streams). I've seen load balancers, proxies, and other
network devices do very bad and unexpected things to HTTP messages
(like insisting zlib compressed content is decoded and then re-encoded
at a different compression level or even stripping compression
completely). I've found that the best way to avoid surprises when
writing protocols on top of HTTP is to use HTTP as a dumb transport as
much as possible to minimize the chances that an "intelligent" agent
between endpoints will muck with your data. While the widespread use of
TLS is mitigating many intermediate network agents interfering with
HTTP, there are still problems at the edges, with e.g. the origin HTTP
server needing to convert HTTP to and from WSGI and buggy or
feature-lacking HTTP client implementations. I've found the best way to
avoid these problems is to avoid using headers like "Content-Encoding"
and to bake as much logic as possible into media types and HTTP message
bodies. The protocol changes in this commit do rely on a custom HTTP
request header and the "Content-Type" headers. But we used them before,
so we shouldn't be increasing our exposure to "bad" HTTP agents.

For the SSH transport, we can't easily implement content negotiation
to determine compression formats because the SSH transport has no
content negotiation capabilities today. And without a framing protocol,
we don't know how much data to feed into a decompressor. So in order
to implement compression support on the SSH transport, we'd need to
invent a mechanism to represent content types and an outer framing
protocol to stream data robustly. While I'm fully capable of doing
that, it is a lot of work and not something that should be undertaken
lightly. My opinion is that if we're going to change the SSH transport
protocol, we should take a long hard look at implementing a grand
unified protocol that attempts to address all the deficiencies with
the existing protocol. While I want this to happen, that would be
massive scope bloat standing in the way of zstd support. So, I've
decided to take the easy solution: the SSH transport will not gain
support for multiple compression formats. Keep in mind it doesn't
support *any* compression today. So essentially nothing is changing
on the SSH front.

#
# This is the mercurial setup script.
#
# 'python setup.py install', or
# 'python setup.py --help' for more options

import sys, platform
if getattr(sys, 'version_info', (0, 0, 0)) < (2, 6, 0, 'final'):
    raise SystemExit("Mercurial requires Python 2.6 or later.")

if sys.version_info[0] >= 3:
    printf = eval('print')
    libdir_escape = 'unicode_escape'
else:
    libdir_escape = 'string_escape'
    def printf(*args, **kwargs):
        f = kwargs.get('file', sys.stdout)
        end = kwargs.get('end', '\n')
        f.write(b' '.join(args) + end)

# Solaris Python packaging brain damage
try:
    import hashlib
    sha = hashlib.sha1()
except ImportError:
    try:
        import sha
        sha.sha # silence unused import warning
    except ImportError:
        raise SystemExit(
            "Couldn't import standard hashlib (incomplete Python install).")

try:
    import zlib
    zlib.compressobj # silence unused import warning
except ImportError:
    raise SystemExit(
        "Couldn't import standard zlib (incomplete Python install).")

# The base IronPython distribution (as of 2.7.1) doesn't support bz2
isironpython = False
try:
    isironpython = (platform.python_implementation()
                    .lower().find("ironpython") != -1)
except AttributeError:
    pass

if isironpython:
    sys.stderr.write("warning: IronPython detected (no bz2 support)\n")
else:
    try:
        import bz2
        bz2.BZ2Compressor # silence unused import warning
    except ImportError:
        raise SystemExit(
            "Couldn't import standard bz2 (incomplete Python install).")

ispypy = "PyPy" in sys.version

import ctypes
import os, stat, subprocess, time
import re
import shutil
import tempfile
from distutils import log
if 'FORCE_SETUPTOOLS' in os.environ:
    from setuptools import setup
else:
    from distutils.core import setup
from distutils.ccompiler import new_compiler
from distutils.core import Command, Extension
from distutils.dist import Distribution
from distutils.command.build import build
from distutils.command.build_ext import build_ext
from distutils.command.build_py import build_py
from distutils.command.build_scripts import build_scripts
from distutils.command.install_lib import install_lib
from distutils.command.install_scripts import install_scripts
from distutils.spawn import spawn, find_executable
from distutils import file_util
from distutils.errors import (
    CCompilerError,
    DistutilsError,
    DistutilsExecError,
)
from distutils.sysconfig import get_python_inc, get_config_var
from distutils.version import StrictVersion

scripts = ['hg']
if os.name == 'nt':
    # We remove hg.bat if we are able to build hg.exe.
    scripts.append('contrib/win32/hg.bat')

# simplified version of distutils.ccompiler.CCompiler.has_function
# that actually removes its temporary files.
def hasfunction(cc, funcname):
    tmpdir = tempfile.mkdtemp(prefix='hg-install-')
    devnull = oldstderr = None
    try:
        fname = os.path.join(tmpdir, 'funcname.c')
        f = open(fname, 'w')
        f.write('int main(void) {\n')
        f.write('    %s();\n' % funcname)
        f.write('}\n')
        f.close()
        # Redirect stderr to /dev/null to hide any error messages
        # from the compiler.
        # This will have to be changed if we ever have to check
        # for a function on Windows.
        devnull = open('/dev/null', 'w')
        oldstderr = os.dup(sys.stderr.fileno())
        os.dup2(devnull.fileno(), sys.stderr.fileno())
        objects = cc.compile([fname], output_dir=tmpdir)
        cc.link_executable(objects, os.path.join(tmpdir, "a.out"))
        return True
    except Exception:
        return False
    finally:
        if oldstderr is not None:
            os.dup2(oldstderr, sys.stderr.fileno())
        if devnull is not None:
            devnull.close()
        shutil.rmtree(tmpdir)

# py2exe needs to be installed to work
try:
    import py2exe
    py2exe.Distribution # silence unused import warning
    py2exeloaded = True
    # import py2exe's patched Distribution class
    from distutils.core import Distribution
except ImportError:
    py2exeloaded = False

def runcmd(cmd, env):
    if (sys.platform == 'plan9'
       and (sys.version_info[0] == 2 and sys.version_info[1] < 7)):
        # subprocess kludge to work around issues in half-baked Python
        # ports, notably bichued/python:
        _, out, err = os.popen3(cmd)
        return str(out), str(err)
    else:
        p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                             stderr=subprocess.PIPE, env=env)
        out, err = p.communicate()
        return out, err

def runhg(cmd, env):
    out, err = runcmd(cmd, env)
    # If root is executing setup.py, but the repository is owned by
    # another user (as in "sudo python setup.py install") we will get
    # trust warnings since the .hg/hgrc file is untrusted. That is
    # fine, we don't want to load it anyway.  Python may warn about
    # a missing __init__.py in mercurial/locale, we also ignore that.
    err = [e for e in err.splitlines()
           if not e.startswith(b'not trusting file') \
              and not e.startswith(b'warning: Not importing') \
              and not e.startswith(b'obsolete feature not enabled')]
    if err:
        printf("stderr from '%s':" % (' '.join(cmd)), file=sys.stderr)
        printf(b'\n'.join([b'  ' + e for e in err]), file=sys.stderr)
        return ''
    return out

version = ''

# Execute hg out of this directory with a custom environment which takes care
# to not use any hgrc files and do no localization.
env = {'HGMODULEPOLICY': 'py',
       'HGRCPATH': '',
       'LANGUAGE': 'C',
       'PATH': ''} # make pypi modules that use os.environ['PATH'] happy
if 'LD_LIBRARY_PATH' in os.environ:
    env['LD_LIBRARY_PATH'] = os.environ['LD_LIBRARY_PATH']
if 'SystemRoot' in os.environ:
    # Copy SystemRoot into the custom environment for Python 2.6
    # under Windows. Otherwise, the subprocess will fail with
    # error 0xc0150004. See: http://bugs.python.org/issue3440
    env['SystemRoot'] = os.environ['SystemRoot']

if os.path.isdir('.hg'):
    cmd = [sys.executable, 'hg', 'log', '-r', '.', '--template', '{tags}\n']
    numerictags = [t for t in runhg(cmd, env).split() if t[0].isdigit()]
    hgid = runhg([sys.executable, 'hg', 'id', '-i'], env).strip()
    if numerictags: # tag(s) found
        version = numerictags[-1]
        if hgid.endswith('+'): # propagate the dirty status to the tag
            version += '+'
    else: # no tag found
        ltagcmd = [sys.executable, 'hg', 'parents', '--template',
                   '{latesttag}']
        ltag = runhg(ltagcmd, env)
        changessincecmd = [sys.executable, 'hg', 'log', '-T', 'x\n', '-r',
                           "only(.,'%s')" % ltag]
        changessince = len(runhg(changessincecmd, env).splitlines())
        version = '%s+%s-%s' % (ltag, changessince, hgid)
    if version.endswith('+'):
        version += time.strftime('%Y%m%d')
elif os.path.exists('.hg_archival.txt'):
    kw = dict([[t.strip() for t in l.split(':', 1)]
               for l in open('.hg_archival.txt')])
    if 'tag' in kw:
        version = kw['tag']
    elif 'latesttag' in kw:
        if 'changessincelatesttag' in kw:
            version = '%(latesttag)s+%(changessincelatesttag)s-%(node).12s' % kw
        else:
            version = '%(latesttag)s+%(latesttagdistance)s-%(node).12s' % kw
    else:
        version = kw.get('node', '')[:12]

if version:
    with open("mercurial/__version__.py", "w") as f:
        f.write('# this file is autogenerated by setup.py\n')
        f.write('version = "%s"\n' % version)

try:
    oldpolicy = os.environ.get('HGMODULEPOLICY', None)
    os.environ['HGMODULEPOLICY'] = 'py'
    from mercurial import __version__
    version = __version__.version
except ImportError:
    version = 'unknown'
finally:
    if oldpolicy is None:
        del os.environ['HGMODULEPOLICY']
    else:
        os.environ['HGMODULEPOLICY'] = oldpolicy

class hgbuild(build):
    # Insert hgbuildmo first so that files in mercurial/locale/ are found
    # when build_py is run next.
    sub_commands = [('build_mo', None)] + build.sub_commands

class hgbuildmo(build):

    description = "build translations (.mo files)"

    def run(self):
        if not find_executable('msgfmt'):
            self.warn("could not find msgfmt executable, no translations "
                     "will be built")
            return

        podir = 'i18n'
        if not os.path.isdir(podir):
            self.warn("could not find %s/ directory" % podir)
            return

        join = os.path.join
        for po in os.listdir(podir):
            if not po.endswith('.po'):
                continue
            pofile = join(podir, po)
            modir = join('locale', po[:-3], 'LC_MESSAGES')
            mofile = join(modir, 'hg.mo')
            mobuildfile = join('mercurial', mofile)
            cmd = ['msgfmt', '-v', '-o', mobuildfile, pofile]
            if sys.platform != 'sunos5':
                # msgfmt on Solaris does not know about -c
                cmd.append('-c')
            self.mkpath(join('mercurial', modir))
            self.make_file([pofile], mobuildfile, spawn, (cmd,))


class hgdist(Distribution):
    pure = False
    cffi = ispypy

    global_options = Distribution.global_options + \
                     [('pure', None, "use pure (slow) Python "
                        "code instead of C extensions"),
                     ]

    def has_ext_modules(self):
        # self.ext_modules is emptied in hgbuildpy.finalize_options which is
        # too late for some cases
        return not self.pure and Distribution.has_ext_modules(self)

# This is ugly as a one-liner. So use a variable.
buildextnegops = dict(getattr(build_ext, 'negative_options', {}))
buildextnegops['no-zstd'] = 'zstd'

class hgbuildext(build_ext):
    user_options = build_ext.user_options + [
        ('zstd', None, 'compile zstd bindings [default]'),
        ('no-zstd', None, 'do not compile zstd bindings'),
    ]

    boolean_options = build_ext.boolean_options + ['zstd']
    negative_opt = buildextnegops

    def initialize_options(self):
        self.zstd = True
        return build_ext.initialize_options(self)

    def build_extensions(self):
        # Filter out zstd if disabled via argument.
        if not self.zstd:
            self.extensions = [e for e in self.extensions
                               if e.name != 'mercurial.zstd']

        return build_ext.build_extensions(self)

    def build_extension(self, ext):
        try:
            build_ext.build_extension(self, ext)
        except CCompilerError:
            if not getattr(ext, 'optional', False):
                raise
            log.warn("Failed to build optional extension '%s' (skipping)",
                     ext.name)

class hgbuildscripts(build_scripts):
    def run(self):
        if os.name != 'nt' or self.distribution.pure:
            return build_scripts.run(self)

        exebuilt = False
        try:
            self.run_command('build_hgexe')
            exebuilt = True
        except (DistutilsError, CCompilerError):
            log.warn('failed to build optional hg.exe')

        if exebuilt:
            # Copying hg.exe to the scripts build directory ensures it is
            # installed by the install_scripts command.
            hgexecommand = self.get_finalized_command('build_hgexe')
            dest = os.path.join(self.build_dir, 'hg.exe')
            self.mkpath(self.build_dir)
            self.copy_file(hgexecommand.hgexepath, dest)

            # Remove hg.bat because it is redundant with hg.exe.
            self.scripts.remove('contrib/win32/hg.bat')

        return build_scripts.run(self)

class hgbuildpy(build_py):
    def finalize_options(self):
        build_py.finalize_options(self)

        if self.distribution.pure:
            self.distribution.ext_modules = []
        elif self.distribution.cffi:
            from mercurial.cffi import (
                bdiff,
                mpatch,
            )
            exts = [mpatch.ffi.distutils_extension(),
                    bdiff.ffi.distutils_extension()]
            # cffi modules go here
            if sys.platform == 'darwin':
                from mercurial.cffi import osutil
                exts.append(osutil.ffi.distutils_extension())
            self.distribution.ext_modules = exts
        else:
            h = os.path.join(get_python_inc(), 'Python.h')
            if not os.path.exists(h):
                raise SystemExit('Python headers are required to build '
                                 'Mercurial but weren\'t found in %s' % h)

    def run(self):
        if self.distribution.pure:
            modulepolicy = 'py'
        else:
            modulepolicy = 'c'
        with open("mercurial/__modulepolicy__.py", "w") as f:
            f.write('# this file is autogenerated by setup.py\n')
            f.write('modulepolicy = "%s"\n' % modulepolicy)

        build_py.run(self)

class buildhgextindex(Command):
    description = 'generate prebuilt index of hgext (for frozen package)'
    user_options = []
    _indexfilename = 'hgext/__index__.py'

    def initialize_options(self):
        pass

    def finalize_options(self):
        pass

    def run(self):
        if os.path.exists(self._indexfilename):
            with open(self._indexfilename, 'w') as f:
                f.write('# empty\n')

        # here no extension enabled, disabled() lists up everything
        code = ('import pprint; from mercurial import extensions; '
                'pprint.pprint(extensions.disabled())')
        out, err = runcmd([sys.executable, '-c', code], env)
        if err:
            raise DistutilsExecError(err)

        with open(self._indexfilename, 'w') as f:
            f.write('# this file is autogenerated by setup.py\n')
            f.write('docs = ')
            f.write(out)

class buildhgexe(build_ext):
    description = 'compile hg.exe from mercurial/exewrapper.c'

    def build_extensions(self):
        if os.name != 'nt':
            return
        if isinstance(self.compiler, HackedMingw32CCompiler):
            self.compiler.compiler_so = self.compiler.compiler # no -mdll
            self.compiler.dll_libraries = [] # no -lmsrvc90

        # Different Python installs can have different Python library
        # names. e.g. the official CPython distribution uses pythonXY.dll
        # and MinGW uses libpythonX.Y.dll.
        _kernel32 = ctypes.windll.kernel32
        _kernel32.GetModuleFileNameA.argtypes = [ctypes.c_void_p,
                                                 ctypes.c_void_p,
                                                 ctypes.c_ulong]
        _kernel32.GetModuleFileNameA.restype = ctypes.c_ulong
        size = 1000
        buf = ctypes.create_string_buffer(size + 1)
        filelen = _kernel32.GetModuleFileNameA(sys.dllhandle, ctypes.byref(buf),
                                               size)

        if filelen > 0 and filelen != size:
            dllbasename = os.path.basename(buf.value)
            if not dllbasename.lower().endswith('.dll'):
                raise SystemExit('Python DLL does not end with .dll: %s' %
                                 dllbasename)
            pythonlib = dllbasename[:-4]
        else:
            log.warn('could not determine Python DLL filename; '
                     'assuming pythonXY')

            hv = sys.hexversion
            pythonlib = 'python%d%d' % (hv >> 24, (hv >> 16) & 0xff)

        log.info('using %s as Python library name' % pythonlib)
        with open('mercurial/hgpythonlib.h', 'wb') as f:
            f.write('/* this file is autogenerated by setup.py */\n')
            f.write('#define HGPYTHONLIB "%s"\n' % pythonlib)
        objects = self.compiler.compile(['mercurial/exewrapper.c'],
                                         output_dir=self.build_temp)
        dir = os.path.dirname(self.get_ext_fullpath('dummy'))
        target = os.path.join(dir, 'hg')
        self.compiler.link_executable(objects, target,
                                      libraries=[],
                                      output_dir=self.build_temp)

    @property
    def hgexepath(self):
        dir = os.path.dirname(self.get_ext_fullpath('dummy'))
        return os.path.join(self.build_temp, dir, 'hg.exe')

class hginstalllib(install_lib):
    '''
    This is a specialization of install_lib that replaces the copy_file used
    there so that it supports setting the mode of files after copying them,
    instead of just preserving the mode that the files originally had.  If your
    system has a umask of something like 027, preserving the permissions when
    copying will lead to a broken install.

    Note that just passing keep_permissions=False to copy_file would be
    insufficient, as it might still be applying a umask.
    '''

    def run(self):
        realcopyfile = file_util.copy_file
        def copyfileandsetmode(*args, **kwargs):
            src, dst = args[0], args[1]
            dst, copied = realcopyfile(*args, **kwargs)
            if copied:
                st = os.stat(src)
                # Persist executable bit (apply it to group and other if user
                # has it)
                if st[stat.ST_MODE] & stat.S_IXUSR:
                    setmode = int('0755', 8)
                else:
                    setmode = int('0644', 8)
                m = stat.S_IMODE(st[stat.ST_MODE])
                m = (m & ~int('0777', 8)) | setmode
                os.chmod(dst, m)
        file_util.copy_file = copyfileandsetmode
        try:
            install_lib.run(self)
        finally:
            file_util.copy_file = realcopyfile

class hginstallscripts(install_scripts):
    '''
    This is a specialization of install_scripts that replaces the @LIBDIR@ with
    the configured directory for modules. If possible, the path is made relative
    to the directory for scripts.
    '''

    def initialize_options(self):
        install_scripts.initialize_options(self)

        self.install_lib = None

    def finalize_options(self):
        install_scripts.finalize_options(self)
        self.set_undefined_options('install',
                                   ('install_lib', 'install_lib'))

    def run(self):
        install_scripts.run(self)

        # It only makes sense to replace @LIBDIR@ with the install path if
        # the install path is known. For wheels, the logic below calculates
        # the libdir to be "../..". This is because the internal layout of a
        # wheel archive looks like:
        #
        #   mercurial-3.6.1.data/scripts/hg
        #   mercurial/__init__.py
        #
        # When installing wheels, the subdirectories of the "<pkg>.data"
        # directory are translated to system local paths and files therein
        # are copied in place. The mercurial/* files are installed into the
        # site-packages directory. However, the site-packages directory
        # isn't known until wheel install time. This means we have no clue
        # at wheel generation time what the installed site-packages directory
        # will be. And, wheels don't appear to provide the ability to register
        # custom code to run during wheel installation. This all means that
        # we can't reliably set the libdir in wheels: the default behavior
        # of looking in sys.path must do.

        if (os.path.splitdrive(self.install_dir)[0] !=
            os.path.splitdrive(self.install_lib)[0]):
            # can't make relative paths from one drive to another, so use an
            # absolute path instead
            libdir = self.install_lib
        else:
            common = os.path.commonprefix((self.install_dir, self.install_lib))
            rest = self.install_dir[len(common):]
            uplevel = len([n for n in os.path.split(rest) if n])

            libdir = uplevel * ('..' + os.sep) + self.install_lib[len(common):]

        for outfile in self.outfiles:
            with open(outfile, 'rb') as fp:
                data = fp.read()

            # skip binary files
            if b'\0' in data:
                continue

            # During local installs, the shebang will be rewritten to the final
            # install path. During wheel packaging, the shebang has a special
            # value.
            if data.startswith(b'#!python'):
                log.info('not rewriting @LIBDIR@ in %s because install path '
                         'not known' % outfile)
                continue

            data = data.replace(b'@LIBDIR@', libdir.encode(libdir_escape))
            with open(outfile, 'wb') as fp:
                fp.write(data)

cmdclass = {'build': hgbuild,
            'build_mo': hgbuildmo,
            'build_ext': hgbuildext,
            'build_py': hgbuildpy,
            'build_scripts': hgbuildscripts,
            'build_hgextindex': buildhgextindex,
            'install_lib': hginstalllib,
            'install_scripts': hginstallscripts,
            'build_hgexe': buildhgexe,
            }

packages = ['mercurial', 'mercurial.hgweb', 'mercurial.httpclient',
            'mercurial.pure',
            'hgext', 'hgext.convert', 'hgext.fsmonitor',
            'hgext.fsmonitor.pywatchman', 'hgext.highlight',
            'hgext.largefiles', 'hgext.zeroconf', 'hgext3rd']

common_depends = ['mercurial/bitmanipulation.h',
                  'mercurial/compat.h',
                  'mercurial/util.h']

osutil_cflags = []
osutil_ldflags = []

# platform specific macros: HAVE_SETPROCTITLE
for plat, func in [(re.compile('freebsd'), 'setproctitle')]:
    if plat.search(sys.platform) and hasfunction(new_compiler(), func):
        osutil_cflags.append('-DHAVE_%s' % func.upper())

if sys.platform == 'darwin':
    osutil_ldflags += ['-framework', 'ApplicationServices']

extmodules = [
    Extension('mercurial.base85', ['mercurial/base85.c'],
              depends=common_depends),
    Extension('mercurial.bdiff', ['mercurial/bdiff.c',
                                  'mercurial/bdiff_module.c'],
              depends=common_depends + ['mercurial/bdiff.h']),
    Extension('mercurial.diffhelpers', ['mercurial/diffhelpers.c'],
              depends=common_depends),
    Extension('mercurial.mpatch', ['mercurial/mpatch.c',
                                   'mercurial/mpatch_module.c'],
              depends=common_depends),
    Extension('mercurial.parsers', ['mercurial/dirs.c',
                                    'mercurial/manifest.c',
                                    'mercurial/parsers.c',
                                    'mercurial/pathencode.c'],
              depends=common_depends),
    Extension('mercurial.osutil', ['mercurial/osutil.c'],
              extra_compile_args=osutil_cflags,
              extra_link_args=osutil_ldflags,
              depends=common_depends),
    Extension('hgext.fsmonitor.pywatchman.bser',
              ['hgext/fsmonitor/pywatchman/bser.c']),
    ]

sys.path.insert(0, 'contrib/python-zstandard')
import setup_zstd
extmodules.append(setup_zstd.get_c_extension(name='mercurial.zstd'))

try:
    from distutils import cygwinccompiler

    # the -mno-cygwin option has been deprecated for years
    compiler = cygwinccompiler.Mingw32CCompiler

    class HackedMingw32CCompiler(cygwinccompiler.Mingw32CCompiler):
        def __init__(self, *args, **kwargs):
            compiler.__init__(self, *args, **kwargs)
            for i in 'compiler compiler_so linker_exe linker_so'.split():
                try:
                    getattr(self, i).remove('-mno-cygwin')
                except ValueError:
                    pass

    cygwinccompiler.Mingw32CCompiler = HackedMingw32CCompiler
except ImportError:
    # the cygwinccompiler package is not available on some Python
    # distributions like the ones from the optware project for Synology
    # DiskStation boxes
    class HackedMingw32CCompiler(object):
        pass

packagedata = {'mercurial': ['locale/*/LC_MESSAGES/hg.mo',
                             'help/*.txt',
                             'help/internals/*.txt',
                             'default.d/*.rc',
                             'dummycert.pem']}

def ordinarypath(p):
    return p and p[0] != '.' and p[-1] != '~'

for root in ('templates',):
    for curdir, dirs, files in os.walk(os.path.join('mercurial', root)):
        curdir = curdir.split(os.sep, 1)[1]
        dirs[:] = filter(ordinarypath, dirs)
        for f in filter(ordinarypath, files):
            f = os.path.join(curdir, f)
            packagedata['mercurial'].append(f)

datafiles = []
setupversion = version
extra = {}

if py2exeloaded:
    extra['console'] = [
        {'script':'hg',
         'copyright':'Copyright (C) 2005-2016 Matt Mackall and others',
         'product_version':version}]
    # sub command of 'build' because 'py2exe' does not handle sub_commands
    build.sub_commands.insert(0, ('build_hgextindex', None))
    # put dlls in sub directory so that they won't pollute PATH
    extra['zipfile'] = 'lib/library.zip'

if os.name == 'nt':
    # Windows binary file versions for exe/dll files must have the
    # form W.X.Y.Z, where W,X,Y,Z are numbers in the range 0..65535
    setupversion = version.split('+', 1)[0]

if sys.platform == 'darwin' and os.path.exists('/usr/bin/xcodebuild'):
    version = runcmd(['/usr/bin/xcodebuild', '-version'], {})[0].splitlines()
    if version:
        version = version[0]
        if sys.version_info[0] == 3:
            version = version.decode('utf-8')
        xcode4 = (version.startswith('Xcode') and
                  StrictVersion(version.split()[1]) >= StrictVersion('4.0'))
        xcode51 = re.match(r'^Xcode\s+5\.1', version) is not None
    else:
        # xcodebuild returns empty on OS X Lion with XCode 4.3 not
        # installed, but instead with only command-line tools. Assume
        # that only happens on >= Lion, thus no PPC support.
        xcode4 = True
        xcode51 = False

    # XCode 4.0 dropped support for ppc architecture, which is hardcoded in
    # distutils.sysconfig
    if xcode4:
        os.environ['ARCHFLAGS'] = ''

    # XCode 5.1 changes clang such that it now fails to compile if the
    # -mno-fused-madd flag is passed, but the version of Python shipped with
    # OS X 10.9 Mavericks includes this flag. This causes problems in all
    # C extension modules, and a bug has been filed upstream at
    # http://bugs.python.org/issue21244. We also need to patch this here
    # so Mercurial can continue to compile in the meantime.
    if xcode51:
        cflags = get_config_var('CFLAGS')
        if cflags and re.search(r'-mno-fused-madd\b', cflags) is not None:
            os.environ['CFLAGS'] = (
                os.environ.get('CFLAGS', '') + ' -Qunused-arguments')

setup(name='mercurial',
      version=setupversion,
      author='Matt Mackall and many others',
      author_email='[e-mail]',
      url='https://mercurial-scm.org/',
      download_url='https://mercurial-scm.org/release/',
      description=('Fast scalable distributed SCM (revision control, version '
                   'control) system'),
      long_description=('Mercurial is a distributed SCM tool written in Python.'
                        ' It is used by a number of large projects that require'
                        ' fast, reliable distributed revision control, such as '
                        'Mozilla.'),
      license='GNU GPLv2 or any later version',
      classifiers=[
          'Development Status :: 6 - Mature',
          'Environment :: Console',
          'Intended Audience :: Developers',
          'Intended Audience :: System Administrators',
          'License :: OSI Approved :: GNU General Public License (GPL)',
          'Natural Language :: Danish',
          'Natural Language :: English',
          'Natural Language :: German',
          'Natural Language :: Italian',
          'Natural Language :: Japanese',
          'Natural Language :: Portuguese (Brazilian)',
          'Operating System :: Microsoft :: Windows',
          'Operating System :: OS Independent',
          'Operating System :: POSIX',
          'Programming Language :: C',
          'Programming Language :: Python',
          'Topic :: Software Development :: Version Control',
      ],
      scripts=scripts,
      packages=packages,
      ext_modules=extmodules,
      data_files=datafiles,
      package_data=packagedata,
      cmdclass=cmdclass,
      distclass=hgdist,
      options={'py2exe': {'packages': ['hgext', 'email']},
               'bdist_mpkg': {'zipdist': False,
                              'license': 'COPYING',
                              'readme': 'contrib/macosx/Readme.html',
                              'welcome': 'contrib/macosx/Welcome.html',
                              },
               },
      **extra)