mdwsetup.py (progoutput): Only read one byte to decide whether there is more.

[runlisp] / mdwsetup.py

### -*-python-*-
###
### Utility module for Python build systems
###
### (c) 2009 Straylight/Edgeware
###

###----- Licensing notice ---------------------------------------------------
###
### This file is part of the Common Files Distribution (`common')
###
### `Common' is free software; you can redistribute it and/or modify
### it under the terms of the GNU General Public License as published by
### the Free Software Foundation; either version 2 of the License, or
### (at your option) any later version.
###
### `Common' is distributed in the hope that it will be useful,
### but WITHOUT ANY WARRANTY; without even the implied warranty of
### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
### GNU General Public License for more details.
###
### You should have received a copy of the GNU General Public License
### along with `common'; if not, write to the Free Software Foundation,
### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

from __future__ import with_statement

import sys as SYS
import os as OS
import re as RE
import subprocess as SUB

import distutils.core as DC
import distutils.log as DL

###--------------------------------------------------------------------------
### Random utilities.

def uniquify(seq):
  """
  Return a list of the elements of SEQ, with duplicates removed.

  Only the first occurrence (according to `==') is left.
  """
  seen = {}
  out = []
  for item in seq:
    if item not in seen:
      seen[item] = True
      out.append(item)
  return out

###--------------------------------------------------------------------------
### Subprocess hacking.

class SubprocessFailure (Exception):
  def __init__(me, file, rc):
    me.args = (file, rc)
    me.file = file
    me.rc = rc
  def __str__(me):
    if OS.WIFEXITED(me.rc):
      return '%s failed (rc = %d)' % (me.file, OS.WEXITSTATUS(me.rc))
    elif OS.WIFSIGNALED(me.rc):
      return '%s died (signal %d)' % (me.file, OS.WTERMSIG(me.rc))
    else:
      return '%s died inexplicably' % (me.file)

def progoutput(command):
  """
  Run the shell COMMAND and return its standard output.

  The COMMAND must produce exactly one line of output, and must exit with
  status zero.
  """
  kid = SUB.Popen(command, stdout = SUB.PIPE)
  try:
    out = kid.stdout.readline()
    junk = kid.stdout.read(1)
  finally:
    kid.stdout.close()
  if junk != '': raise ValueError \
    ("Child process `%s' produced unspected output %r" % (command, junk))
  rc = kid.wait()
  if rc != 0: raise SubprocessFailure(command, rc)
  return out.rstrip('\n')

###--------------------------------------------------------------------------
### External library packages.

INCLUDEDIRS = []
LIBDIRS = []
LIBS = []

def pkg_config(pkg, version):
  """
  Find the external package PKG and store the necessary compiler flags.

  The include-directory names are stored in INCLUDEDIRS; the
  library-directory names are in LIBDIRS; and the library names themselves
  are in LIBS.
  """

  def weird(what, word):
    raise ValueError \
      ("Unexpected `%s' item `%s' from package `%s'" % (what, word, pkg))

  spec = '%s >= %s' % (pkg, version)

  try: cflags = OS.environ["%s_CFLAGS" % pkg]
  except KeyError: cflags = progoutput(['pkg-config', '--cflags', spec])
  for word in cflags.split():
    if word.startswith('-I'): INCLUDEDIRS.append(word[2:])
    else: weird('CFLAGS', word)
  try: libs = OS.environ["%s_LIBS" % pkg]
  except KeyError: libs = progoutput(['pkg-config', '--libs', spec])
  for word in libs.split():
    if word.startswith('-L'): LIBDIRS.append(word[2:])
    elif word.startswith('-l'): LIBS.append(word[2:])
    else: weird('LIBS', word)

###--------------------------------------------------------------------------
### Substituting variables in files.

class BaseGenFile (object):
  """
  A base class for file generators.

  Instances of subclasses are suitable for listing in the `genfiles'
  attribute, passed to `setup'.

  Subclasses need to implement `_gen', which should simply do the work of
  generating the target file from its sources.  This class will print
  progress messages and check whether the target actually needs regenerating.
  """
  def __init__(me, target, sources = []):
    me.target = target
    me.sources = sources
  def _needs_update_p(me):
    if not OS.path.exists(me.target): return True
    t_target = OS.stat(me.target).st_mtime
    for s in me.sources:
      if OS.stat(s).st_mtime >= t_target: return True
    return False
  def gen(me, dry_run_p = False):
    if not me._needs_update_p(): return
    DL.log(DL.INFO, "generate `%s' from %s", me.target,
           ', '.join("`%s'" % s for s in me.sources))
    if not dry_run_p: me._gen()
  def clean(me, dry_run_p):
    if not OS.path.exists(me.target): return
    DL.log(DL.INFO, "delete `%s'", me.target)
    if not dry_run_p: OS.remove(me.target)

class Derive (BaseGenFile):
  """
  Derive TARGET from SOURCE by making simple substitutions.

  The SOURCE may contain markers %FOO%; these are replaced by SUBSTMAP['FOO']
  in the TARGET file.
  """
  RX_SUBST = RE.compile(r'\%(\w+)\%')
  def __init__(me, target, source, substmap):
    BaseGenFile.__init__(me, target, [source])
    me._map = substmap
  def _gen(me):
    temp = me.target + '.new'
    with open(temp, 'w') as ft:
      with open(me.sources[0], 'r') as fs:
        for line in fs:
          ft.write(me.RX_SUBST.sub((lambda m: me._map[m.group(1)]), line))
    OS.rename(temp, me.target)

class Generate (BaseGenFile):
  """
  Generate TARGET by running the SOURCE Python script.

  If SOURCE is omitted, replace the extension of TARGET by `.py'.
  """
  def __init__(me, target, source = None):
    if source is None: source = OS.path.splitext(target)[0] + '.py'
    BaseGenFile.__init__(me, target, [source])
  def _gen(me):
    temp = me.target + '.new'
    with open(temp, 'w') as ft:
      rc = SUB.call([SYS.executable, me.sources[0]], stdout = ft)
    if rc != 0: raise SubprocessFailure(me.sources[0], rc << 8)
    OS.rename(temp, me.target)

## Backward compatibility.
def derive(target, source, substmap): Derive(target, source, substmap).gen()
def generate(target, source = None): Generate(target, source).gen()

###--------------------------------------------------------------------------
### Discovering version numbers.

def auto_version(writep = True):
  """
  Returns the package version number.

  As a side-effect, if WRITEP is true, then write the version number to the
  RELEASE file so that it gets included in distributions.

  All of this is for backwards compatibility.  New projects should omit the
  `version' keyword entirely and let `setup' discover it and write it into
  tarballs automatically.
  """
  version = progoutput(['./auto-version'])
  if writep:
    with open('RELEASE.new', 'w') as ft: ft.write('%s\n' % version)
    OS.rename('RELEASE.new', 'RELEASE')
  return version

###--------------------------------------------------------------------------
### Adding new commands.

CMDS = {}

class CommandClass (type):
  """
  Metaclass for command classes: automatically adds them to the `CMDS' map.
  """
  def __new__(cls, name, supers, dict):
    c = super(CommandClass, cls).__new__(cls, name, supers, dict)
    try: name = c.NAME
    except AttributeError: pass
    else: CMDS[name] = c
    return c

class Command (DC.Command, object):
  """
  Base class for `mdwsetup' command classes.

  This provides the automatic registration machinery, via the metaclass, and
  also trivial implementations of various responsibilities of `DC.Command'
  methods and attributes.
  """
  __metaclass__ = CommandClass
  user_options = []
  def initialize_options(me): pass
  def finalize_options(me): pass
  def run_subs(me):
    for s in me.get_sub_commands(): me.run_command(s)

###--------------------------------------------------------------------------
### Some handy new commands.

class distdir (Command):
  NAME = 'distdir'
  description = "print the distribution directory name to stdout"
  def run(me):
    d = me.distribution
    print '%s-%s' % (d.get_name(), d.get_version())

class build_gen(Command):
  """
  Generate files, according to the `genfiles'.

  The `genfiles' keyword argument to `setup' lists a number of objects which
  guide the generation of output files.  These objects must implement the
  following methods.

  clean(DRY_RUN_P)      Remove the output files.

  gen(DRY_RUN_P)        Generate the output files, if they don't exist or are
                        out of date with respect to their prerequisites.

  If DRY_RUN_P is true then the methods must not actually do anything with a
  lasting effect, but should print progress messages as usual.
  """
  NAME = 'build_gen'
  description = "build generated source files"
  def run(me):
    d = me.distribution
    for g in d.genfiles: g.gen(dry_run_p = me.dry_run)

from distutils.command.build import build as _build
class build (_build, Command):
  ## Add `build_gen' early in the list of subcommands.
  NAME = 'build'
  sub_commands = [('build_gen', lambda me: me.distribution.genfiles)]
  sub_commands += _build.sub_commands

class clean_gen(Command):
  """
  Remove the generated files, as listed in `genfiles'.

  See the `build_gen' command for more detailed information.
  """
  NAME = 'clean_gen'
  description = "clean generated source files"
  def run(me):
    d = me.distribution
    for g in d.genfiles: g.clean(dry_run_p = me.dry_run)

class clean_others(Command):
  """
  Remove the files listed in the `cleanfiles' argument to `setup'.
  """
  NAME = 'clean_others'
  description = "clean miscellaneous output files"
  def run(me):
    d = me.distribution
    for f in d.cleanfiles:
      if not OS.path.exists(f): continue
      DL.log(DL.INFO, "delete `%s'", f)
      if not me.dry_run: OS.remove(f)

from distutils.command.clean import clean as _clean
class clean (_clean, Command):
  ## Add `clean_gen' and `clean_others' to the list of subcommands.
  NAME = 'clean'
  sub_commands = [('clean_gen', lambda me: me.distribution.genfiles),
                  ('clean_others', lambda me: me.distribution.cleanfiles)]
  sub_commands += _clean.sub_commands
  def run(me):
    me.run_subs()
    _clean.run(me)

from distutils.command.sdist import sdist as _sdist
class sdist (_sdist, Command):
  ## Write a `RELEASE' file to the output, if we extracted the version number
  ## from version control.  Also arrange to dereference symbolic links while
  ## copying.  Symlinks to directories will go horribly wrong, so don't do
  ## that.
  NAME = 'sdist'
  def make_release_tree(me, base_dir, files):
    _sdist.make_release_tree(me, base_dir, files)
    d = me.distribution
    if d._auto_version_p:
      v = d.metadata.get_version()
      DL.log(DL.INFO, "write `RELEASE' file: %s" % v)
      with open(OS.path.join(base_dir, 'RELEASE'), 'w') as f:
        f.write('%s\n' % v)
  def copy_file(me, infile, outfile, link = None, *args, **kw):
    if OS.path.islink(infile): link = None
    return _sdist.copy_file(me, infile, outfile, link = link, *args, **kw)

###--------------------------------------------------------------------------
### Our own version of `setup'.

class Dist (DC.Distribution):
  ## Like the usual version, but with some additional attributes to support
  ## our enhanced commands.
  def __init__(me, attrs = None):
    me.genfiles = []
    me.cleanfiles = []
    me._auto_version_p = False
    DC.Distribution.__init__(me, attrs)
    if me.metadata.version is None:
      me.metadata.version = auto_version(writep = False)
      me._auto_version_p = True
    me.cleanfiles = set(me.cleanfiles)
    me.cleanfiles.add('MANIFEST')

def setup(cmdclass = {}, distclass = Dist, **kw):
  ## Like the usual version, but provides defaults more suited to our
  ## purposes.
  cmds = dict()
  cmds.update(CMDS)
  cmds.update(cmdclass)
  DC.setup(cmdclass = cmds, distclass = distclass, **kw)

###----- That's all, folks --------------------------------------------------