# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
from __future__ import absolute_import, print_function, unicode_literals
import __builtin__
import inspect
import logging
import os
import re
import sys
import types
from collections import OrderedDict
from contextlib import contextmanager
from functools import wraps
from mozbuild.configure.options import (
CommandLineHelper,
ConflictingOptionError,
InvalidOptionError,
NegativeOptionValue,
Option,
OptionValue,
PositiveOptionValue,
)
from mozbuild.configure.help import HelpFormatter
from mozbuild.configure.util import (
ConfigureOutputHandler,
getpreferredencoding,
LineIO,
)
from mozbuild.util import (
exec_,
memoize,
ReadOnlyDict,
ReadOnlyNamespace,
)
import mozpack.path as mozpath
class ConfigureError(Exception):
pass
class SandboxDependsFunction(object):
'''Sandbox-visible representation of @depends functions.'''
def __init__(self, unsandboxed):
self._or = unsandboxed.__or__
self._and = unsandboxed.__and__
self._getattr = unsandboxed.__getattr__
def __call__(self, *arg, **kwargs):
raise ConfigureError('The `%s` function may not be called'
% self.__name__)
def __or__(self, other):
if not isinstance(other, SandboxDependsFunction):
raise ConfigureError('Can only do binary arithmetic operations '
'with another @depends function.')
return self._or(other).sandboxed
def __and__(self, other):
if not isinstance(other, SandboxDependsFunction):
raise ConfigureError('Can only do binary arithmetic operations '
'with another @depends function.')
return self._and(other).sandboxed
def __getattr__(self, key):
return self._getattr(key).sandboxed
def __nonzero__(self):
raise ConfigureError(
'Cannot do boolean operations on @depends functions.')
class DependsFunction(object):
__slots__ = (
'_func', '_name', 'dependencies', 'when', 'sandboxed', 'sandbox',
'_result')
def __init__(self, sandbox, func, dependencies, when=None):
assert isinstance(sandbox, ConfigureSandbox)
assert not inspect.isgeneratorfunction(func)
self._func = func
self._name = func.__name__
self.dependencies = dependencies
self.sandboxed = wraps(func)(SandboxDependsFunction(self))
self.sandbox = sandbox
self.when = when
sandbox._depends[self.sandboxed] = self
# Only @depends functions with a dependency on '--help' are executed
# immediately. Everything else is queued for later execution.
if sandbox._help_option in dependencies:
sandbox._value_for(self)
elif not sandbox._help:
sandbox._execution_queue.append((sandbox._value_for, (self,)))
@property
def name(self):
return self._name
@name.setter
def name(self, value):
self._name = value
@property
def sandboxed_dependencies(self):
return [
d.sandboxed if isinstance(d, DependsFunction) else d
for d in self.dependencies
]
@memoize
def result(self, need_help_dependency=False):
if self.when and not self.sandbox._value_for(self.when,
need_help_dependency):
return None
resolved_args = [self.sandbox._value_for(d, need_help_dependency)
for d in self.dependencies]
return self._func(*resolved_args)
def __repr__(self):
return '<%s.%s %s(%s)>' % (
self.__class__.__module__,
self.__class__.__name__,
self.name,
', '.join(repr(d) for d in self.dependencies),
)
def __or__(self, other):
if isinstance(other, SandboxDependsFunction):
other = self.sandbox._depends.get(other)
assert isinstance(other, DependsFunction)
assert self.sandbox is other.sandbox
return CombinedDependsFunction(self.sandbox, self.or_impl,
(self, other))
@staticmethod
def or_impl(iterable):
# Applies "or" to all the items of iterable.
# e.g. if iterable contains a, b and c, returns `a or b or c`.
for i in iterable:
if i:
return i
return i
def __and__(self, other):
if isinstance(other, SandboxDependsFunction):
other = self.sandbox._depends.get(other)
assert isinstance(other, DependsFunction)
assert self.sandbox is other.sandbox
return CombinedDependsFunction(self.sandbox, self.and_impl,
(self, other))
@staticmethod
def and_impl(iterable):
# Applies "and" to all the items of iterable.
# e.g. if iterable contains a, b and c, returns `a and b and c`.
for i in iterable:
if not i:
return i
return i
def __getattr__(self, key):
if key.startswith('_'):
return super(DependsFunction, self).__getattr__(key)
# Our function may return None or an object that simply doesn't have
# the wanted key. In that case, just return None.
return TrivialDependsFunction(
self.sandbox, lambda x: getattr(x, key, None), [self], self.when)
class TrivialDependsFunction(DependsFunction):
'''Like a DependsFunction, but the linter won't expect it to have a
dependency on --help ever.'''
class CombinedDependsFunction(DependsFunction):
def __init__(self, sandbox, func, dependencies):
flatten_deps = []
for d in dependencies:
if isinstance(d, CombinedDependsFunction) and d._func is func:
for d2 in d.dependencies:
if d2 not in flatten_deps:
flatten_deps.append(d2)
elif d not in flatten_deps:
flatten_deps.append(d)
super(CombinedDependsFunction, self).__init__(
sandbox, func, flatten_deps)
@memoize
def result(self, need_help_dependency=False):
resolved_args = (self.sandbox._value_for(d, need_help_dependency)
for d in self.dependencies)
return self._func(resolved_args)
def __eq__(self, other):
return (isinstance(other, self.__class__) and
self._func is other._func and
set(self.dependencies) == set(other.dependencies))
def __ne__(self, other):
return not self == other
class SandboxedGlobal(dict):
'''Identifiable dict type for use as function global'''
def forbidden_import(*args, **kwargs):
raise ImportError('Importing modules is forbidden')
class ConfigureSandbox(dict):
"""Represents a sandbox for executing Python code for build configuration.
This is a different kind of sandboxing than the one used for moz.build
processing.
The sandbox has 9 primitives:
- option
- depends
- template
- imports
- include
- set_config
- set_define
- imply_option
- only_when
`option`, `include`, `set_config`, `set_define` and `imply_option` are
functions. `depends`, `template`, and `imports` are decorators. `only_when`
is a context_manager.
These primitives are declared as name_impl methods to this class and
the mapping name -> name_impl is done automatically in __getitem__.
Additional primitives should be frowned upon to keep the sandbox itself as
simple as possible. Instead, helpers should be created within the sandbox
with the existing primitives.
The sandbox is given, at creation, a dict where the yielded configuration
will be stored.
config = {}
sandbox = ConfigureSandbox(config)
sandbox.run(path)
do_stuff(config)
"""
# The default set of builtins. We expose unicode as str to make sandboxed
# files more python3-ready.
BUILTINS = ReadOnlyDict({
b: getattr(__builtin__, b)
for b in ('None', 'False', 'True', 'int', 'bool', 'any', 'all', 'len',
'list', 'tuple', 'set', 'dict', 'isinstance', 'getattr',
'hasattr', 'enumerate', 'range', 'zip')
}, __import__=forbidden_import, str=unicode)
# Expose a limited set of functions from os.path
OS = ReadOnlyNamespace(path=ReadOnlyNamespace(**{
k: getattr(mozpath, k, getattr(os.path, k))
for k in ('abspath', 'basename', 'dirname', 'isabs', 'join',
'normcase', 'normpath', 'realpath', 'relpath')
}))
def __init__(self, config, environ=os.environ, argv=sys.argv,
stdout=sys.stdout, stderr=sys.stderr, logger=None):
dict.__setitem__(self, '__builtins__', self.BUILTINS)
self._paths = []
self._all_paths = set()
self._templates = set()
# Associate SandboxDependsFunctions to DependsFunctions.
self._depends = OrderedDict()
self._seen = set()
# Store the @imports added to a given function.
self._imports = {}
self._options = OrderedDict()
# Store raw option (as per command line or environment) for each Option
self._raw_options = OrderedDict()
# Store options added with `imply_option`, and the reason they were
# added (which can either have been given to `imply_option`, or
# inferred. Their order matters, so use a list.
self._implied_options = []
# Store all results from _prepare_function
self._prepared_functions = set()
# Queue of functions to execute, with their arguments
self._execution_queue = []
# Store the `when`s associated to some options.
self._conditions = {}
# A list of conditions to apply as a default `when` for every *_impl()
self._default_conditions = []
self._helper = CommandLineHelper(environ, argv)
assert isinstance(config, dict)
self._config = config
if logger is None:
logger = moz_logger = logging.getLogger('moz.configure')
logger.setLevel(logging.DEBUG)
formatter = logging.Formatter('%(levelname)s: %(message)s')
handler = ConfigureOutputHandler(stdout, stderr)
handler.setFormatter(formatter)
queue_debug = handler.queue_debug
logger.addHandler(handler)
else:
assert isinstance(logger, logging.Logger)
moz_logger = None
@contextmanager
def queue_debug():
yield
# Some callers will manage to log a bytestring with characters in it
# that can't be converted to ascii. Make our log methods robust to this
# by detecting the encoding that a producer is likely to have used.
encoding = getpreferredencoding()
def wrapped_log_method(logger, key):
method = getattr(logger, key)
if not encoding:
return method
def wrapped(*args, **kwargs):
out_args = [
arg.decode(encoding) if isinstance(arg, str) else arg
for arg in args
]
return method(*out_args, **kwargs)
return wrapped
log_namespace = {
k: wrapped_log_method(logger, k)
for k in ('debug', 'info', 'warning', 'error')
}
log_namespace['queue_debug'] = queue_debug
self.log_impl = ReadOnlyNamespace(**log_namespace)
self._help = None
self._help_option = self.option_impl('--help',
help='print this message')
self._seen.add(self._help_option)
self._always = DependsFunction(self, lambda: True, [])
self._never = DependsFunction(self, lambda: False, [])
if self._value_for(self._help_option):
self._help = HelpFormatter(argv[0])
self._help.add(self._help_option)
elif moz_logger:
handler = logging.FileHandler('config.log', mode='w', delay=True)
handler.setFormatter(formatter)
logger.addHandler(handler)
def include_file(self, path):
'''Include one file in the sandbox. Users of this class probably want
to use `run` instead.
Note: this will execute all template invocations, as well as @depends
functions that depend on '--help', but nothing else.
'''
if self._paths:
path = mozpath.join(mozpath.dirname(self._paths[-1]), path)
path = mozpath.normpath(path)
if not mozpath.basedir(path, (mozpath.dirname(self._paths[0]),)):
raise ConfigureError(
'Cannot include `%s` because it is not in a subdirectory '
'of `%s`' % (path, mozpath.dirname(self._paths[0])))
else:
path = mozpath.realpath(mozpath.abspath(path))
if path in self._all_paths:
raise ConfigureError(
'Cannot include `%s` because it was included already.' % path)
self._paths.append(path)
self._all_paths.add(path)
source = open(path, 'rb').read()
code = compile(source, path, 'exec')
exec_(code, self)
self._paths.pop(-1)
def run(self, path=None):
'''Executes the given file within the sandbox, as well as everything
pending from any other included file, and ensure the overall
consistency of the executed script(s).'''
if path:
self.include_file(path)
for option in self._options.itervalues():
# All options must be referenced by some @depends function
if option not in self._seen:
raise ConfigureError(
'Option `%s` is not handled ; reference it with a @depends'
% option.option
)
self._value_for(option)
# All implied options should exist.
for implied_option in self._implied_options:
value = self._resolve(implied_option.value,
need_help_dependency=False)
if value is not None:
raise ConfigureError(
'`%s`, emitted from `%s` line %d, is unknown.'
% (implied_option.option, implied_option.caller[1],
implied_option.caller[2]))
# All options should have been removed (handled) by now.
for arg in self._helper:
without_value = arg.split('=', 1)[0]
# raise InvalidOptionError('Unknown option: %s' % without_value)
# Run the execution queue
for func, args in self._execution_queue:
func(*args)
if self._help:
with LineIO(self.log_impl.info) as out:
self._help.usage(out)
def __getitem__(self, key):
impl = '%s_impl' % key
func = getattr(self, impl, None)
if func:
return func
return super(ConfigureSandbox, self).__getitem__(key)
def __setitem__(self, key, value):
if (key in self.BUILTINS or key == '__builtins__' or
hasattr(self, '%s_impl' % key)):
raise KeyError('Cannot reassign builtins')
if inspect.isfunction(value) and value not in self._templates:
value, _ = self._prepare_function(value)
elif (not isinstance(value, SandboxDependsFunction) and
value not in self._templates and
not (inspect.isclass(value) and issubclass(value, Exception))):
raise KeyError('Cannot assign `%s` because it is neither a '
'@depends nor a @template' % key)
if isinstance(value, SandboxDependsFunction):
self._depends[value].name = key
return super(ConfigureSandbox, self).__setitem__(key, value)
def _resolve(self, arg, need_help_dependency=True):
if isinstance(arg, SandboxDependsFunction):
return self._value_for_depends(self._depends[arg],
need_help_dependency)
return arg
def _value_for(self, obj, need_help_dependency=False):
if isinstance(obj, SandboxDependsFunction):
assert obj in self._depends
return self._value_for_depends(self._depends[obj],
need_help_dependency)
elif isinstance(obj, DependsFunction):
return self._value_for_depends(obj, need_help_dependency)
elif isinstance(obj, Option):
return self._value_for_option(obj)
assert False
@memoize
def _value_for_depends(self, obj, need_help_dependency=False):
return obj.result(need_help_dependency)
@memoize
def _value_for_option(self, option):
implied = {}
for implied_option in self._implied_options[:]:
if implied_option.name not in (option.name, option.env):
continue
self._implied_options.remove(implied_option)
if (implied_option.when and
not self._value_for(implied_option.when)):
continue
value = self._resolve(implied_option.value,
need_help_dependency=False)
if value is not None:
if isinstance(value, OptionValue):
pass
elif value is True:
value = PositiveOptionValue()
elif value is False or value == ():
value = NegativeOptionValue()
elif isinstance(value, types.StringTypes):
value = PositiveOptionValue((value,))
elif isinstance(value, tuple):
value = PositiveOptionValue(value)
else:
raise TypeError("Unexpected type: '%s'"
% type(value).__name__)
opt = value.format(implied_option.option)
self._helper.add(opt, 'implied')
implied[opt] = implied_option
try:
value, option_string = self._helper.handle(option)
except ConflictingOptionError as e:
reason = implied[e.arg].reason
if isinstance(reason, Option):
reason = self._raw_options.get(reason) or reason.option
reason = reason.split('=', 1)[0]
raise InvalidOptionError(
"'%s' implied by '%s' conflicts with '%s' from the %s"
% (e.arg, reason, e.old_arg, e.old_origin))
if option_string:
self._raw_options[option] = option_string
when = self._conditions.get(option)
if (when and not self._value_for(when, need_help_dependency=True) and
value is not None and value.origin != 'default'):
if value.origin == 'environment':
# The value we return doesn't really matter, because of the
# requirement for @depends to have the same when.
return None
raise InvalidOptionError(
'%s is not available in this configuration'
% option_string.split('=', 1)[0])
return value
def _dependency(self, arg, callee_name, arg_name=None):
if isinstance(arg, types.StringTypes):
prefix, name, values = Option.split_option(arg)
if values != ():
raise ConfigureError("Option must not contain an '='")
if name not in self._options:
raise ConfigureError("'%s' is not a known option. "
"Maybe it's declared too late?"
% arg)
arg = self._options[name]
self._seen.add(arg)
elif isinstance(arg, SandboxDependsFunction):
assert arg in self._depends
arg = self._depends[arg]
else:
raise TypeError(
"Cannot use object of type '%s' as %sargument to %s"
% (type(arg).__name__, '`%s` ' % arg_name if arg_name else '',
callee_name))
return arg
def _normalize_when(self, when, callee_name):
if when is True:
when = self._always
elif when is False:
when = self._never
elif when is not None:
when = self._dependency(when, callee_name, 'when')
if self._default_conditions:
# Create a pseudo @depends function for the combination of all
# default conditions and `when`.
dependencies = [when] if when else []
dependencies.extend(self._default_conditions)
if len(dependencies) == 1:
return dependencies[0]
return CombinedDependsFunction(self, all, dependencies)
return when
@contextmanager
def only_when_impl(self, when):
'''Implementation of only_when()
`only_when` is a context manager that essentially makes calls to
other sandbox functions within the context block ignored.
'''
when = self._normalize_when(when, 'only_when')
if when and self._default_conditions[-1:] != [when]:
self._default_conditions.append(when)
yield
self._default_conditions.pop()
else:
yield
def option_impl(self, *args, **kwargs):
'''Implementation of option()
This function creates and returns an Option() object, passing it the
resolved arguments (uses the result of functions when functions are
passed). In most cases, the result of this function is not expected to
be used.
Command line argument/environment variable parsing for this Option is
handled here.
'''
when = self._normalize_when(kwargs.get('when'), 'option')
args = [self._resolve(arg) for arg in args]
kwargs = {k: self._resolve(v) for k, v in kwargs.iteritems()
if k != 'when'}
option = Option(*args, **kwargs)
if when:
self._conditions[option] = when
if option.name in self._options:
raise ConfigureError('Option `%s` already defined' % option.option)
if option.env in self._options:
raise ConfigureError('Option `%s` already defined' % option.env)
if option.name:
self._options[option.name] = option
if option.env:
self._options[option.env] = option
if self._help and (when is None or
self._value_for(when, need_help_dependency=True)):
self._help.add(option)
return option
def depends_impl(self, *args, **kwargs):
'''Implementation of @depends()
This function is a decorator. It returns a function that subsequently
takes a function and returns a dummy function. The dummy function
identifies the actual function for the sandbox, while preventing
further function calls from within the sandbox.
@depends() takes a variable number of option strings or dummy function
references. The decorated function is called as soon as the decorator
is called, and the arguments it receives are the OptionValue or
function results corresponding to each of the arguments to @depends.
As an exception, when a HelpFormatter is attached, only functions that
have '--help' in their @depends argument list are called.
The decorated function is altered to use a different global namespace
for its execution. This different global namespace exposes a limited
set of functions from os.path.
'''
for k in kwargs:
if k != 'when':
raise TypeError(
"depends_impl() got an unexpected keyword argument '%s'"
% k)
when = self._normalize_when(kwargs.get('when'), '@depends')
if not when and not args:
raise ConfigureError('@depends needs at least one argument')
dependencies = tuple(self._dependency(arg, '@depends') for arg in args)
conditions = [
self._conditions[d]
for d in dependencies
if d in self._conditions and isinstance(d, Option)
]
for c in conditions:
if c != when:
raise ConfigureError('@depends function needs the same `when` '
'as options it depends on')
def decorator(func):
if inspect.isgeneratorfunction(func):
raise ConfigureError(
'Cannot decorate generator functions with @depends')
func, glob = self._prepare_function(func)
depends = DependsFunction(self, func, dependencies, when=when)
return depends.sandboxed
return decorator
def include_impl(self, what, when=None):
'''Implementation of include().
Allows to include external files for execution in the sandbox.
It is possible to use a @depends function as argument, in which case
the result of the function is the file name to include. This latter
feature is only really meant for --enable-application/--enable-project.
'''
with self.only_when_impl(when):
what = self._resolve(what)
if what:
if not isinstance(what, types.StringTypes):
raise TypeError("Unexpected type: '%s'" % type(what).__name__)
self.include_file(what)
def template_impl(self, func):
'''Implementation of @template.
This function is a decorator. Template functions are called
immediately. They are altered so that their global namespace exposes
a limited set of functions from os.path, as well as `depends` and
`option`.
Templates allow to simplify repetitive constructs, or to implement
helper decorators and somesuch.
'''
template, glob = self._prepare_function(func)
glob.update(
(k[:-len('_impl')], getattr(self, k))
for k in dir(self) if k.endswith('_impl') and k != 'template_impl'
)
glob.update((k, v) for k, v in self.iteritems() if k not in glob)
# Any function argument to the template must be prepared to be sandboxed.
# If the template itself returns a function (in which case, it's very
# likely a decorator), that function must be prepared to be sandboxed as
# well.
def wrap_template(template):
isfunction = inspect.isfunction
def maybe_prepare_function(obj):
if isfunction(obj):
func, _ = self._prepare_function(obj)
return func
return obj
# The following function may end up being prepared to be sandboxed,
# so it mustn't depend on anything from the global scope in this
# file. It can however depend on variables from the closure, thus
# maybe_prepare_function and isfunction are declared above to be
# available there.
@self.wraps(template)
def wrapper(*args, **kwargs):
args = [maybe_prepare_function(arg) for arg in args]
kwargs = {k: maybe_prepare_function(v)
for k, v in kwargs.iteritems()}
ret = template(*args, **kwargs)
if isfunction(ret):
# We can't expect the sandboxed code to think about all the
# details of implementing decorators, so do some of the
# work for them. If the function takes exactly one function
# as argument and returns a function, it must be a
# decorator, so mark the returned function as wrapping the
# function passed in.
if len(args) == 1 and not kwargs and isfunction(args[0]):
ret = self.wraps(args[0])(ret)
return wrap_template(ret)
return ret
return wrapper
wrapper = wrap_template(template)
self._templates.add(wrapper)
return wrapper
def wraps(self, func):
return wraps(func)
RE_MODULE = re.compile('^[a-zA-Z0-9_\.]+$')
def imports_impl(self, _import, _from=None, _as=None):
'''Implementation of @imports.
This decorator imports the given _import from the given _from module
optionally under a different _as name.
The options correspond to the various forms for the import builtin.
@imports('sys')
@imports(_from='mozpack', _import='path', _as='mozpath')
'''
for value, required in (
(_import, True), (_from, False), (_as, False)):
if not isinstance(value, types.StringTypes) and (
required or value is not None):
raise TypeError("Unexpected type: '%s'" % type(value).__name__)
if value is not None and not self.RE_MODULE.match(value):
raise ValueError("Invalid argument to @imports: '%s'" % value)
if _as and '.' in _as:
raise ValueError("Invalid argument to @imports: '%s'" % _as)
def decorator(func):
if func in self._templates:
raise ConfigureError(
'@imports must appear after @template')
if func in self._depends:
raise ConfigureError(
'@imports must appear after @depends')
# For the imports to apply in the order they appear in the
# .configure file, we accumulate them in reverse order and apply
# them later.
imports = self._imports.setdefault(func, [])
imports.insert(0, (_from, _import, _as))
return func
return decorator
def _apply_imports(self, func, glob):
for _from, _import, _as in self._imports.get(func, ()):
_from = '%s.' % _from if _from else ''
if _as:
glob[_as] = self._get_one_import('%s%s' % (_from, _import))
else:
what = _import.split('.')[0]
glob[what] = self._get_one_import('%s%s' % (_from, what))
def _get_one_import(self, what):
# The special `__sandbox__` module gives access to the sandbox
# instance.
if what == '__sandbox__':
return self
# Special case for the open() builtin, because otherwise, using it
# fails with "IOError: file() constructor not accessible in
# restricted mode"
if what == '__builtin__.open':
return lambda *args, **kwargs: open(*args, **kwargs)
# Until this proves to be a performance problem, just construct an
# import statement and execute it.
import_line = ''
if '.' in what:
_from, what = what.rsplit('.', 1)
import_line += 'from %s ' % _from
import_line += 'import %s as imported' % what
glob = {}
exec_(import_line, {}, glob)
return glob['imported']
def _resolve_and_set(self, data, name, value, when=None):
# Don't set anything when --help was on the command line
if self._help:
return
if when and not self._value_for(when):
return
name = self._resolve(name, need_help_dependency=False)
if name is None:
return
if not isinstance(name, types.StringTypes):
raise TypeError("Unexpected type: '%s'" % type(name).__name__)
if name in data:
raise ConfigureError(
"Cannot add '%s' to configuration: Key already "
"exists" % name)
value = self._resolve(value, need_help_dependency=False)
if value is not None:
data[name] = value
def set_config_impl(self, name, value, when=None):
'''Implementation of set_config().
Set the configuration items with the given name to the given value.
Both `name` and `value` can be references to @depends functions,
in which case the result from these functions is used. If the result
of either function is None, the configuration item is not set.
'''
when = self._normalize_when(when, 'set_config')
self._execution_queue.append((
self._resolve_and_set, (self._config, name, value, when)))
def set_define_impl(self, name, value, when=None):
'''Implementation of set_define().
Set the define with the given name to the given value. Both `name` and
`value` can be references to @depends functions, in which case the
result from these functions is used. If the result of either function
is None, the define is not set. If the result is False, the define is
explicitly undefined (-U).
'''
when = self._normalize_when(when, 'set_define')
defines = self._config.setdefault('DEFINES', {})
self._execution_queue.append((
self._resolve_and_set, (defines, name, value, when)))
def imply_option_impl(self, option, value, reason=None, when=None):
'''Implementation of imply_option().
Injects additional options as if they had been passed on the command
line. The `option` argument is a string as in option()'s `name` or
`env`. The option must be declared after `imply_option` references it.
The `value` argument indicates the value to pass to the option.
It can be:
- True. In this case `imply_option` injects the positive option
(--enable-foo/--with-foo).
imply_option('--enable-foo', True)
imply_option('--disable-foo', True)
are both equivalent to `--enable-foo` on the command line.
- False. In this case `imply_option` injects the negative option
(--disable-foo/--without-foo).
imply_option('--enable-foo', False)
imply_option('--disable-foo', False)
are both equivalent to `--disable-foo` on the command line.
- None. In this case `imply_option` does nothing.
imply_option('--enable-foo', None)
imply_option('--disable-foo', None)
are both equivalent to not passing any flag on the command line.
- a string or a tuple. In this case `imply_option` injects the positive
option with the given value(s).
imply_option('--enable-foo', 'a')
imply_option('--disable-foo', 'a')
are both equivalent to `--enable-foo=a` on the command line.
imply_option('--enable-foo', ('a', 'b'))
imply_option('--disable-foo', ('a', 'b'))
are both equivalent to `--enable-foo=a,b` on the command line.
Because imply_option('--disable-foo', ...) can be misleading, it is
recommended to use the positive form ('--enable' or '--with') for
`option`.
The `value` argument can also be (and usually is) a reference to a
@depends function, in which case the result of that function will be
used as per the descripted mapping above.
The `reason` argument indicates what caused the option to be implied.
It is necessary when it cannot be inferred from the `value`.
'''
when = self._normalize_when(when, 'imply_option')
# Don't do anything when --help was on the command line
if self._help:
return
if not reason and isinstance(value, SandboxDependsFunction):
deps = self._depends[value].dependencies
possible_reasons = [d for d in deps if d != self._help_option]
if len(possible_reasons) == 1:
if isinstance(possible_reasons[0], Option):
reason = possible_reasons[0]
if not reason and (isinstance(value, (bool, tuple)) or
isinstance(value, types.StringTypes)):
# A reason can be provided automatically when imply_option
# is called with an immediate value.
_, filename, line, _, _, _ = inspect.stack()[1]
reason = "imply_option at %s:%s" % (filename, line)
if not reason:
raise ConfigureError(
"Cannot infer what implies '%s'. Please add a `reason` to "
"the `imply_option` call."
% option)
prefix, name, values = Option.split_option(option)
if values != ():
raise ConfigureError("Implied option must not contain an '='")
self._implied_options.append(ReadOnlyNamespace(
option=option,
prefix=prefix,
name=name,
value=value,
caller=inspect.stack()[1],
reason=reason,
when=when,
))
def _prepare_function(self, func):
'''Alter the given function global namespace with the common ground
for @depends, and @template.
'''
if not inspect.isfunction(func):
raise TypeError("Unexpected type: '%s'" % type(func).__name__)
if func in self._prepared_functions:
return func, func.func_globals
glob = SandboxedGlobal(
(k, v) for k, v in func.func_globals.iteritems()
if (inspect.isfunction(v) and v not in self._templates) or (
inspect.isclass(v) and issubclass(v, Exception))
)
glob.update(
__builtins__=self.BUILTINS,
__file__=self._paths[-1] if self._paths else '',
__name__=self._paths[-1] if self._paths else '',
os=self.OS,
log=self.log_impl,
)
# The execution model in the sandbox doesn't guarantee the execution
# order will always be the same for a given function, and if it uses
# variables from a closure that are changed after the function is
# declared, depending when the function is executed, the value of the
# variable can differ. For consistency, we force the function to use
# the value from the earliest it can be run, which is at declaration.
# Note this is not entirely bullet proof (if the value is e.g. a list,
# the list contents could have changed), but covers the bases.
closure = None
if func.func_closure:
def makecell(content):
def f():
content
return f.func_closure[0]
closure = tuple(makecell(cell.cell_contents)
for cell in func.func_closure)
new_func = self.wraps(func)(types.FunctionType(
func.func_code,
glob,
func.__name__,
func.func_defaults,
closure
))
@self.wraps(new_func)
def wrapped(*args, **kwargs):
if func in self._imports:
self._apply_imports(func, glob)
del self._imports[func]
return new_func(*args, **kwargs)
self._prepared_functions.add(wrapped)
return wrapped, glob