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# Copyright (C) 2003-2018 Free Software Foundation, Inc.
# This program 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, or (at your option)
# any later version.
# This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
package Automake::Item;
use 5.006;
use strict;
use Carp;
use Automake::ChannelDefs;
use Automake::DisjConditions;
=head1 NAME
Automake::Item - base class for Automake::Variable and Automake::Rule
=head1 DESCRIPTION
=head2 Methods
=over 4
=item C<new Automake::Item $name>
Create and return an empty Item called C<$name>.
=cut
sub new ($$)
{
my ($class, $name) = @_;
my $self = {
name => $name,
defs => {},
conds => {},
};
bless $self, $class;
return $self;
}
=item C<$item-E<gt>name>
Return the name of C<$item>.
=cut
sub name ($)
{
my ($self) = @_;
return $self->{'name'};
}
=item C<$item-E<gt>def ($cond)>
Return the definition for this item in condition C<$cond>, if it
exists. Return 0 otherwise.
=cut
sub def ($$)
{
# This method is called very often, so keep it small and fast. We
# don't mind the extra undefined items introduced by lookup failure;
# avoiding this with 'exists' means doing two hash lookup on
# success, and proved worse on benchmark.
my $def = $_[0]->{'defs'}{$_[1]};
return defined $def && $def;
}
=item C<$item-E<gt>rdef ($cond)>
Return the definition for this item in condition C<$cond>. Abort with
an internal error if the item was not defined under this condition.
The I<r> in front of C<def> stands for I<required>. One
should call C<rdef> to assert the conditional definition's existence.
=cut
sub rdef ($$)
{
my ($self, $cond) = @_;
my $d = $self->def ($cond);
prog_error ("undefined condition '" . $cond->human . "' for '"
. $self->name . "'\n" . $self->dump)
unless $d;
return $d;
}
=item C<$item-E<gt>set ($cond, $def)>
Add a new definition to an existing item.
=cut
sub set ($$$)
{
my ($self, $cond, $def) = @_;
$self->{'defs'}{$cond} = $def;
$self->{'conds'}{$cond} = $cond;
}
=item C<$var-E<gt>conditions>
Return an L<Automake::DisjConditions> describing the conditions that
that an item is defined in.
These are all the conditions for which is would be safe to call
C<rdef>.
=cut
sub conditions ($)
{
my ($self) = @_;
prog_error ("self is not a reference")
unless ref $self;
return new Automake::DisjConditions (values %{$self->{'conds'}});
}
=item C<@missing_conds = $var-E<gt>not_always_defined_in_cond ($cond)>
Check whether C<$var> is always defined for condition C<$cond>.
Return a list of conditions where the definition is missing.
For instance, given
if COND1
if COND2
A = foo
D = d1
else
A = bar
D = d2
endif
else
D = d3
endif
if COND3
A = baz
B = mumble
endif
C = mumble
we should have (we display result as conditional strings in this
illustration, but we really return DisjConditions objects):
var ('A')->not_always_defined_in_cond ('COND1_TRUE COND2_TRUE')
=> ()
var ('A')->not_always_defined_in_cond ('COND1_TRUE')
=> ()
var ('A')->not_always_defined_in_cond ('TRUE')
=> ("COND1_FALSE COND3_FALSE")
var ('B')->not_always_defined_in_cond ('COND1_TRUE')
=> ("COND1_TRUE COND3_FALSE")
var ('C')->not_always_defined_in_cond ('COND1_TRUE')
=> ()
var ('D')->not_always_defined_in_cond ('TRUE')
=> ()
var ('Z')->not_always_defined_in_cond ('TRUE')
=> ("TRUE")
=cut
sub not_always_defined_in_cond ($$)
{
my ($self, $cond) = @_;
# Compute the subconditions where $var isn't defined.
return
$self->conditions
->sub_conditions ($cond)
->invert
->multiply ($cond);
}
1;