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# Copyright (C) 2002-2013 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 <http://www.gnu.org/licenses/>.

package Automake::ChannelDefs;

use Automake::Config;
BEGIN
{
  if ($perl_threads)
    {
      require threads;
      import threads;
    }
}
use Automake::Channels;

=head1 NAME

Automake::ChannelDefs - channel definitions for Automake and helper functions

=head1 SYNOPSIS

  use Automake::ChannelDefs;

  Automake::ChannelDefs::usage ();
  prog_error ($MESSAGE, [%OPTIONS]);
  error ($WHERE, $MESSAGE, [%OPTIONS]);
  error ($MESSAGE);
  fatal ($WHERE, $MESSAGE, [%OPTIONS]);
  fatal ($MESSAGE);
  verb ($MESSAGE, [%OPTIONS]);
  switch_warning ($CATEGORY);
  parse_WARNINGS ();
  parse_warnings ($OPTION, $ARGUMENT);
  Automake::ChannelDefs::set_strictness ($STRICTNESS_NAME);

=head1 DESCRIPTION

This packages defines channels that can be used in Automake to
output diagnostics and other messages (via C<msg()>).  It also defines
some helper function to enable or disable these channels, and some
shorthand function to output on specific channels.

=cut

use 5.006;
use strict;
use Exporter;

use vars qw (@ISA @EXPORT);

@ISA = qw (Exporter);
@EXPORT = qw (&prog_error &error &fatal &verb
	      &switch_warning &parse_WARNINGS &parse_warnings);

=head2 CHANNELS

The following channels can be used as the first argument of
C<Automake::Channel::msg>.  For some of them we list a shorthand
function that makes the code more readable.

=over 4

=item C<fatal>

Fatal errors.  Use C<&fatal> to send messages over this channel.

=item C<error>

Common errors.  Use C<&error> to send messages over this channel.

=item C<error-gnu>

Errors related to GNU Standards.

=item C<error-gnu/warn>

Errors related to GNU Standards that should be warnings in 'foreign' mode.

=item C<error-gnits>

Errors related to GNITS Standards (silent by default).

=item C<automake>

Internal errors.  Use C<&prog_error> to send messages over this channel.

=item C<gnu>

Warnings related to GNU Coding Standards.

=item C<obsolete>

Warnings about obsolete features (silent by default).

=item C<override>

Warnings about user redefinitions of Automake rules or
variables (silent by default).

=item C<portability>

Warnings about non-portable constructs.

=item C<extra-portability>

Extra warnings about non-portable constructs covering obscure tools.

=item C<syntax>

Warnings about weird syntax, unused variables, typos...

=item C<unsupported>

Warnings about unsupported (or mis-supported) features.

=item C<verb>

Messages output in C<--verbose> mode.  Use C<&verb> to send such messages.

=item C<note>

Informative messages.

=back

=cut

# Initialize our list of error/warning channels.
# Do not forget to update &usage and the manual
# if you add or change a warning channel.

register_channel 'fatal', type => 'fatal', uniq_part => UP_NONE, ordered => 0;
register_channel 'error', type => 'error';
register_channel 'error-gnu', type => 'error';
register_channel 'error-gnu/warn', type => 'error';
register_channel 'error-gnits', type => 'error', silent => 1;
register_channel 'automake', type => 'fatal', backtrace => 1,
  header => ("####################\n" .
	     "## Internal Error ##\n" .
	     "####################\n"),
  footer => "\nPlease contact <$PACKAGE_BUGREPORT>.",
  uniq_part => UP_NONE, ordered => 0;

register_channel 'extra-portability', type => 'warning', silent => 1;
register_channel 'gnu', type => 'warning';
register_channel 'obsolete', type => 'warning';
register_channel 'override', type => 'warning', silent => 1;
register_channel 'portability', type => 'warning', silent => 1;
register_channel 'portability-recursive', type => 'warning', silent => 1;
register_channel 'syntax', type => 'warning';
register_channel 'unsupported', type => 'warning';

register_channel 'verb', type => 'debug', silent => 1, uniq_part => UP_NONE,
  ordered => 0;
register_channel 'note', type => 'debug', silent => 0;

setup_channel_type 'warning', header => 'warning: ';
setup_channel_type 'error', header => 'error: ';
setup_channel_type 'fatal', header => 'error: ';

=head2 FUNCTIONS

=over 4

=item C<usage ()>

Display warning categories.

=cut

sub usage ()
{
  print <<EOF;
Warning categories include:
  gnu                GNU coding standards (default in gnu and gnits modes)
  obsolete           obsolete features or constructions
  override           user redefinitions of Automake rules or variables
  portability        portability issues (default in gnu and gnits modes)
  extra-portability  extra portability issues related to obscure tools
  syntax             dubious syntactic constructs (default)
  unsupported        unsupported or incomplete features (default)
  all                all the warnings
  no-CATEGORY        turn off warnings in CATEGORY
  none               turn off all the warnings
  error              treat warnings as errors
EOF
}

=item C<prog_error ($MESSAGE, [%OPTIONS])>

Signal a programming error (on channel C<automake>),
display C<$MESSAGE>, and exit 1.

=cut

sub prog_error ($;%)
{
  my ($msg, %opts) = @_;
  msg 'automake', '', $msg, %opts;
}

=item C<error ($WHERE, $MESSAGE, [%OPTIONS])>

=item C<error ($MESSAGE)>

Uncategorized errors.

=cut

sub error ($;$%)
{
  my ($where, $msg, %opts) = @_;
  msg ('error', $where, $msg, %opts);
}

=item C<fatal ($WHERE, $MESSAGE, [%OPTIONS])>

=item C<fatal ($MESSAGE)>

Fatal errors.

=cut

sub fatal ($;$%)
{
  my ($where, $msg, %opts) = @_;
  msg ('fatal', $where, $msg, %opts);
}

=item C<verb ($MESSAGE, [%OPTIONS])>

C<--verbose> messages.

=cut

sub verb ($;%)
{
  my ($msg, %opts) = @_;
  $msg = "thread " . threads->tid . ": " . $msg
    if $perl_threads;
  msg 'verb', '', $msg, %opts;
}

=item C<switch_warning ($CATEGORY)>

If C<$CATEGORY> is C<mumble>, turn on channel C<mumble>.
If it's C<no-mumble>, turn C<mumble> off.
Else handle C<all> and C<none> for completeness.

=cut

sub switch_warning ($)
{
  my ($cat) = @_;
  my $has_no = 0;

  if ($cat =~ /^no-(.*)$/)
    {
      $cat = $1;
      $has_no = 1;
    }

  if ($cat eq 'all')
    {
      setup_channel_type 'warning', silent => $has_no;
    }
  elsif ($cat eq 'none')
    {
      setup_channel_type 'warning', silent => ! $has_no;
    }
  elsif ($cat eq 'error')
    {
      $warnings_are_errors = ! $has_no;
      # Set exit code if Perl warns about something
      # (like uninitialized variables).
      $SIG{"__WARN__"} =
	$has_no ? 'DEFAULT' : sub { print STDERR @_; $exit_code = 1; };
    }
  elsif (channel_type ($cat) eq 'warning')
    {
      setup_channel $cat, silent => $has_no;
      #
      # Handling of portability warnings is trickier.  For relevant tests,
      # see 'dollarvar2', 'extra-portability' and 'extra-portability3'.
      #
      # -Wportability-recursive and -Wno-portability-recursive should not
      # have any effect on other 'portability' or 'extra-portability'
      # warnings, so there's no need to handle them separately or ad-hoc.
      #
      if ($cat eq 'extra-portability' && ! $has_no) # -Wextra-portability
        {
          # -Wextra-portability must enable 'portability' and
          # 'portability-recursive' warnings.
          setup_channel 'portability', silent => 0;
          setup_channel 'portability-recursive', silent => 0;
        }
      if ($cat eq 'portability') # -Wportability or -Wno-portability
        {
          if ($has_no) # -Wno-portability
            {
              # -Wno-portability must disable 'extra-portability' and
              # 'portability-recursive' warnings.
              setup_channel 'portability-recursive', silent => 1;
              setup_channel 'extra-portability', silent => 1;
            }
          else # -Wportability
            {
              # -Wportability must enable 'portability-recursive'
              # warnings.  But it should have no influence over the
              # 'extra-portability' warnings.
              setup_channel 'portability-recursive', silent => 0;
            }
        }
    }
  else
    {
      return 1;
    }
  return 0;
}

=item C<parse_WARNINGS ()>

Parse the WARNINGS environment variable.

=cut

sub parse_WARNINGS ()
{
  if (exists $ENV{'WARNINGS'})
    {
      # Ignore unknown categories.  This is required because WARNINGS
      # should be honored by many tools.
      switch_warning $_ foreach (split (',', $ENV{'WARNINGS'}));
    }
}

=item C<parse_warnings ($OPTION, $ARGUMENT)>

Parse the argument of C<--warning=CATEGORY> or C<-WCATEGORY>.

C<$OPTIONS> is C<"--warning"> or C<"-W">, C<$ARGUMENT> is C<CATEGORY>.

This is meant to be used as an argument to C<Getopt>.

=cut

sub parse_warnings ($$)
{
  my ($opt, $categories) = @_;

  foreach my $cat (split (',', $categories))
    {
      msg 'unsupported', "unknown warning category '$cat'"
	if switch_warning $cat;
    }
}

=item C<set_strictness ($STRICTNESS_NAME)>

Configure channels for strictness C<$STRICTNESS_NAME>.

=cut

sub set_strictness ($)
{
  my ($name) = @_;

  if ($name eq 'gnu')
    {
      setup_channel 'error-gnu', silent => 0;
      setup_channel 'error-gnu/warn', silent => 0, type => 'error';
      setup_channel 'error-gnits', silent => 1;
      setup_channel 'portability', silent => 0;
      setup_channel 'extra-portability', silent => 1;
      setup_channel 'gnu', silent => 0;
    }
  elsif ($name eq 'gnits')
    {
      setup_channel 'error-gnu', silent => 0;
      setup_channel 'error-gnu/warn', silent => 0, type => 'error';
      setup_channel 'error-gnits', silent => 0;
      setup_channel 'portability', silent => 0;
      setup_channel 'extra-portability', silent => 1;
      setup_channel 'gnu', silent => 0;
    }
  elsif ($name eq 'foreign')
    {
      setup_channel 'error-gnu', silent => 1;
      setup_channel 'error-gnu/warn', silent => 0, type => 'warning';
      setup_channel 'error-gnits', silent => 1;
      setup_channel 'portability', silent => 1;
      setup_channel 'extra-portability', silent => 1;
      setup_channel 'gnu', silent => 1;
    }
  else
    {
      prog_error "level '$name' not recognized";
    }
}

=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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