cpython/Lib/distutils/cmd.py

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"""distutils.cmd
Provides the Command class, the base class for the command classes
in the distutils.command package."""
# created 2000/04/03, Greg Ward
# (extricated from core.py; actually dates back to the beginning)
__revision__ = "$Id$"
import sys, string
from types import *
from distutils.errors import *
from distutils import util
class Command:
"""Abstract base class for defining command classes, the "worker bees"
of the Distutils. A useful analogy for command classes is to
think of them as subroutines with local variables called
"options". The options are "declared" in 'initialize_options()'
and "defined" (given their final values, aka "finalized") in
'finalize_options()', both of which must be defined by every
command class. The distinction between the two is necessary
because option values might come from the outside world (command
line, option file, ...), and any options dependent on other
options must be computed *after* these outside influences have
been processed -- hence 'finalize_options()'. The "body" of the
subroutine, where it does all its work based on the values of its
options, is the 'run()' method, which must also be implemented by
every command class."""
# -- Creation/initialization methods -------------------------------
def __init__ (self, dist):
"""Create and initialize a new Command object. Most importantly,
invokes the 'initialize_options()' method, which is the
real initializer and depends on the actual command being
instantiated."""
# late import because of mutual dependence between these classes
from distutils.dist import Distribution
if not isinstance (dist, Distribution):
raise TypeError, "dist must be a Distribution instance"
if self.__class__ is Command:
raise RuntimeError, "Command is an abstract class"
self.distribution = dist
self.initialize_options ()
# Per-command versions of the global flags, so that the user can
# customize Distutils' behaviour command-by-command and let some
# commands fallback on the Distribution's behaviour. None means
# "not defined, check self.distribution's copy", while 0 or 1 mean
# false and true (duh). Note that this means figuring out the real
# value of each flag is a touch complicatd -- hence "self.verbose"
# (etc.) will be handled by __getattr__, below.
self._verbose = None
self._dry_run = None
# The 'help' flag is just used for command-line parsing, so
# none of that complicated bureaucracy is needed.
self.help = 0
# 'ready' records whether or not 'finalize_options()' has been
# called. 'finalize_options()' itself should not pay attention to
# this flag: it is the business of 'ensure_ready()', which always
# calls 'finalize_options()', to respect/update it.
self.ready = 0
# __init__ ()
def __getattr__ (self, attr):
if attr in ('verbose', 'dry_run'):
myval = getattr (self, "_" + attr)
if myval is None:
return getattr (self.distribution, attr)
else:
return myval
# Needed because some Command methods assume 'self.force' exists,
# but not all commands define 'self.force'. Ugh.
elif attr == 'force':
return None
else:
raise AttributeError, attr
def ensure_ready (self):
if not self.ready:
self.finalize_options ()
self.ready = 1
# Subclasses must define:
# initialize_options()
# provide default values for all options; may be overridden
# by Distutils client, by command-line options, or by options
# from option file
# finalize_options()
# decide on the final values for all options; this is called
# after all possible intervention from the outside world
# (command-line, option file, etc.) has been processed
# run()
# run the command: do whatever it is we're here to do,
# controlled by the command's various option values
def initialize_options (self):
"""Set default values for all the options that this command
supports. Note that these defaults may be overridden
by the command-line supplied by the user; thus, this is
not the place to code dependencies between options; generally,
'initialize_options()' implementations are just a bunch
of "self.foo = None" assignments.
This method must be implemented by all command classes."""
raise RuntimeError, \
"abstract method -- subclass %s must override" % self.__class__
def finalize_options (self):
"""Set final values for all the options that this command
supports. This is always called as late as possible, ie.
after any option assignments from the command-line or from
other commands have been done. Thus, this is the place to to
code option dependencies: if 'foo' depends on 'bar', then it
is safe to set 'foo' from 'bar' as long as 'foo' still has
the same value it was assigned in 'initialize_options()'.
This method must be implemented by all command classes."""
raise RuntimeError, \
"abstract method -- subclass %s must override" % self.__class__
def run (self):
"""A command's raison d'etre: carry out the action it exists
to perform, controlled by the options initialized in
'initialize_options()', customized by the user and other
commands, and finalized in 'finalize_options()'. All
terminal output and filesystem interaction should be done by
'run()'.
This method must be implemented by all command classes."""
raise RuntimeError, \
"abstract method -- subclass %s must override" % self.__class__
def announce (self, msg, level=1):
"""If the Distribution instance to which this command belongs
has a verbosity level of greater than or equal to 'level'
print 'msg' to stdout."""
if self.verbose >= level:
print msg
# -- Option query/set methods --------------------------------------
def get_option (self, option):
"""Return the value of a single option for this command. Raise
DistutilsOptionError if 'option' is not known."""
try:
return getattr (self, option)
except AttributeError:
raise DistutilsOptionError, \
"command %s: no such option %s" % \
(self.get_command_name(), option)
def get_options (self, *options):
"""Return (as a tuple) the values of several options for this
command. Raise DistutilsOptionError if any of the options in
'options' are not known."""
values = []
try:
for opt in options:
values.append (getattr (self, opt))
except AttributeError, name:
raise DistutilsOptionError, \
"command %s: no such option %s" % \
(self.get_command_name(), name)
return tuple (values)
def set_option (self, option, value):
"""Set the value of a single option for this command. Raise
DistutilsOptionError if 'option' is not known."""
if not hasattr (self, option):
raise DistutilsOptionError, \
"command '%s': no such option '%s'" % \
(self.get_command_name(), option)
if value is not None:
setattr (self, option, value)
def set_options (self, **optval):
"""Set the values of several options for this command. Raise
DistutilsOptionError if any of the options specified as
keyword arguments are not known."""
for k in optval.keys():
if optval[k] is not None:
self.set_option (k, optval[k])
# -- Convenience methods for commands ------------------------------
def get_command_name (self):
if hasattr (self, 'command_name'):
return self.command_name
else:
return self.__class__.__name__
def set_undefined_options (self, src_cmd, *option_pairs):
"""Set the values of any "undefined" options from corresponding
option values in some other command object. "Undefined" here
means "is None", which is the convention used to indicate
that an option has not been changed between
'set_initial_values()' and 'set_final_values()'. Usually
called from 'set_final_values()' for options that depend on
some other command rather than another option of the same
command. 'src_cmd' is the other command from which option
values will be taken (a command object will be created for it
if necessary); the remaining arguments are
'(src_option,dst_option)' tuples which mean "take the value
of 'src_option' in the 'src_cmd' command object, and copy it
to 'dst_option' in the current command object"."""
# Option_pairs: list of (src_option, dst_option) tuples
src_cmd_obj = self.distribution.find_command_obj (src_cmd)
src_cmd_obj.ensure_ready ()
try:
for (src_option, dst_option) in option_pairs:
if getattr (self, dst_option) is None:
self.set_option (dst_option,
src_cmd_obj.get_option (src_option))
except AttributeError, name:
# duh, which command?
raise DistutilsOptionError, "unknown option %s" % name
def find_peer (self, command, create=1):
"""Wrapper around Distribution's 'find_command_obj()' method:
find (create if necessary and 'create' is true) the command
object for 'command'.."""
cmd_obj = self.distribution.find_command_obj (command, create)
cmd_obj.ensure_ready ()
return cmd_obj
def get_peer_option (self, command, option):
"""Find or create the command object for 'command', and return
its 'option' option."""
cmd_obj = self.find_peer (command)
return cmd_obj.get_option (option)
def run_peer (self, command):
"""Run some other command: uses the 'run_command()' method of
Distribution, which creates the command object if necessary
and then invokes its 'run()' method."""
self.distribution.run_command (command)
# -- External world manipulation -----------------------------------
def warn (self, msg):
sys.stderr.write ("warning: %s: %s\n" %
(self.get_command_name(), msg))
def execute (self, func, args, msg=None, level=1):
"""Perform some action that affects the outside world (eg.
by writing to the filesystem). Such actions are special because
they should be disabled by the "dry run" flag, and should
announce themselves if the current verbosity level is high
enough. This method takes care of all that bureaucracy for you;
all you have to do is supply the funtion to call and an argument
tuple for it (to embody the "external action" being performed),
a message to print if the verbosity level is high enough, and an
optional verbosity threshold."""
# Generate a message if we weren't passed one
if msg is None:
msg = "%s %s" % (func.__name__, `args`)
if msg[-2:] == ',)': # correct for singleton tuple
msg = msg[0:-2] + ')'
# Print it if verbosity level is high enough
self.announce (msg, level)
# And do it, as long as we're not in dry-run mode
if not self.dry_run:
apply (func, args)
# execute()
def mkpath (self, name, mode=0777):
util.mkpath (name, mode,
self.verbose, self.dry_run)
def copy_file (self, infile, outfile,
preserve_mode=1, preserve_times=1, link=None, level=1):
"""Copy a file respecting verbose, dry-run and force flags. (The
former two default to whatever is in the Distribution object, and
the latter defaults to false for commands that don't define it.)"""
return util.copy_file (infile, outfile,
preserve_mode, preserve_times,
not self.force,
link,
self.verbose >= level,
self.dry_run)
def copy_tree (self, infile, outfile,
preserve_mode=1, preserve_times=1, preserve_symlinks=0,
level=1):
"""Copy an entire directory tree respecting verbose, dry-run,
and force flags."""
return util.copy_tree (infile, outfile,
preserve_mode,preserve_times,preserve_symlinks,
not self.force,
self.verbose >= level,
self.dry_run)
def move_file (self, src, dst, level=1):
"""Move a file respecting verbose and dry-run flags."""
return util.move_file (src, dst,
self.verbose >= level,
self.dry_run)
def spawn (self, cmd, search_path=1, level=1):
from distutils.spawn import spawn
spawn (cmd, search_path,
self.verbose >= level,
self.dry_run)
def make_archive (self, base_name, format,
root_dir=None, base_dir=None):
util.make_archive (base_name, format, root_dir, base_dir,
self.verbose, self.dry_run)
def make_file (self, infiles, outfile, func, args,
exec_msg=None, skip_msg=None, level=1):
"""Special case of 'execute()' for operations that process one or
more input files and generate one output file. Works just like
'execute()', except the operation is skipped and a different
message printed if 'outfile' already exists and is newer than all
files listed in 'infiles'. If the command defined 'self.force',
and it is true, then the command is unconditionally run -- does no
timestamp checks."""
if exec_msg is None:
exec_msg = "generating %s from %s" % \
(outfile, string.join (infiles, ', '))
if skip_msg is None:
skip_msg = "skipping %s (inputs unchanged)" % outfile
# Allow 'infiles' to be a single string
if type (infiles) is StringType:
infiles = (infiles,)
elif type (infiles) not in (ListType, TupleType):
raise TypeError, \
"'infiles' must be a string, or a list or tuple of strings"
# If 'outfile' must be regenerated (either because it doesn't
# exist, is out-of-date, or the 'force' flag is true) then
# perform the action that presumably regenerates it
if self.force or util.newer_group (infiles, outfile):
self.execute (func, args, exec_msg, level)
# Otherwise, print the "skip" message
else:
self.announce (skip_msg, level)
# make_file ()
# class Command
if __name__ == "__main__":
print "ok"