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# Copyright (C) 2002-2018 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::Location;
use 5.006;
=head1 NAME
Automake::Location - a class for location tracking, with a stack of contexts
=head1 SYNOPSIS
use Automake::Location;
# Create a new Location object
my $where = new Automake::Location "foo.c:13";
# Change the location
$where->set ("foo.c:14");
# Get the location (without context).
# Here this should print "foo.c:14"
print $where->get, "\n";
# Push a context, and change the location
$where->push_context ("included from here");
$where->set ("bar.h:1");
# Print the location and the stack of context (for debugging)
print $where->dump;
# This should display
# bar.h:1:
# foo.c:14: included from here
# Get the contexts (list of [$location_string, $description])
for my $pair (reverse $where->contexts)
{
my ($loc, $descr) = @{$pair};
...
}
# Pop a context, and reset the location to the previous context.
$where->pop_context;
# Clone a Location. Use this when storing the state of a location
# that would otherwise be modified.
my $where_copy = $where->clone;
# Serialize a Location object (for passing through a thread queue,
# for example)
my @array = $where->serialize ();
# De-serialize: recreate a Location object from a queue.
my $where = new Automake::Location::deserialize ($queue);
=head1 DESCRIPTION
C<Location> objects are used to keep track of locations in Automake,
and used to produce diagnostics.
A C<Location> object is made of two parts: a location string, and
a stack of contexts.
For instance if C<VAR> is defined at line 1 in F<bar.h> which was
included at line 14 in F<foo.c>, then the location string should be
C<"bar.h:10"> and the context should be the pair (C<"foo.c:14">,
C<"included from here">).
Section I<SYNOPSIS> shows how to setup such a C<Location>, and access
the location string or the stack of contexts.
You can pass a C<Location> to C<Automake::Channels::msg>.
=cut
=head2 Methods
=over
=item C<$where = new Automake::Location ([$position])>
Create and return a new Location object.
=cut
sub new ($;$)
{
my ($class, $position) = @_;
my $self = {
position => $position,
contexts => [],
};
bless $self, $class;
return $self;
}
=item C<$location-E<gt>set ($position)>
Change the location to be C<$position>.
=cut
sub set ($$)
{
my ($self, $position) = @_;
$self->{'position'} = $position;
}
=item C<$location-E<gt>get>
Get the location (without context).
=cut
sub get ($)
{
my ($self) = @_;
return $self->{'position'};
}
=item C<$location-E<gt>push_context ($context)>
Push a context to the location.
=cut
sub push_context ($$)
{
my ($self, $context) = @_;
push @{$self->{'contexts'}}, [$self->get, $context];
$self->set (undef);
}
=item C<$where = $location-E<gt>pop_context ($context)>
Pop a context, and reset the location to the previous context.
=cut
sub pop_context ($)
{
my ($self) = @_;
my $pair = pop @{$self->{'contexts'}};
$self->set ($pair->[0]);
return @{$pair};
}
=item C<@contexts = $location-E<gt>get_contexts>
Return the array of contexts.
=cut
sub get_contexts ($)
{
my ($self) = @_;
return @{$self->{'contexts'}};
}
=item C<$location = $location-E<gt>clone>
Clone a Location. Use this when storing the state of a location
that would otherwise be modified.
=cut
sub clone ($)
{
my ($self) = @_;
my $other = new Automake::Location ($self->get);
my @contexts = $self->get_contexts;
for my $pair (@contexts)
{
push @{$other->{'contexts'}}, [@{$pair}];
}
return $other;
}
=item C<$res = $location-E<gt>dump>
Print the location and the stack of context (for debugging).
=cut
sub dump ($)
{
my ($self) = @_;
my $res = ($self->get || 'INTERNAL') . ":\n";
for my $pair (reverse $self->get_contexts)
{
$res .= $pair->[0] || 'INTERNAL';
$res .= ": $pair->[1]\n";
}
return $res;
}
=item C<@array = $location-E<gt>serialize>
Serialize a Location object (for passing through a thread queue,
for example).
=cut
sub serialize ($)
{
my ($self) = @_;
my @serial = ();
push @serial, $self->get;
my @contexts = $self->get_contexts;
for my $pair (@contexts)
{
push @serial, @{$pair};
}
push @serial, undef;
return @serial;
}
=item C<new Automake::Location::deserialize ($queue)>
De-serialize: recreate a Location object from a queue.
=cut
sub deserialize ($)
{
my ($queue) = @_;
my $position = $queue->dequeue ();
my $self = new Automake::Location $position;
while (my $position = $queue->dequeue ())
{
my $context = $queue->dequeue ();
push @{$self->{'contexts'}}, [$position, $context];
}
return $self;
}
=back
=head1 SEE ALSO
L<Automake::Channels>
=head1 HISTORY
Written by Alexandre Duret-Lutz E<lt>F<adl@gnu.org>E<gt>.
=cut
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