#!/usr/bin/perl

=head1 NAME

dh - debhelper command sequencer

=cut

use strict;
use warnings;
use constant {
	'UNSKIPPABLE_CLI_OPTIONS_BUILD_SYSTEM' => q(-S|--buildsystem|-D|--sourcedir(?:ectory)?|-B|--builddir(?:ectory)?),
	'BUILD_STAMP_FILE'                     => 'debian/debhelper-build-stamp',
};
use Debian::Debhelper::Dh_Lib;
use Debian::Debhelper::Sequence;
use Debian::Debhelper::SequencerUtil;
use Debian::Debhelper::DH::SequenceState ();

our $VERSION = DH_BUILTIN_VERSION;

=head1 SYNOPSIS

B<dh> I<sequence> [B<--with> I<addon>[B<,>I<addon> ...]] [B<--list>] [S<I<debhelper options>>]

=head1 DESCRIPTION

B<dh> runs a sequence of debhelper commands. The supported I<sequence>s
correspond to the targets of a F<debian/rules> file: B<build-arch>,
B<build-indep>, B<build>, B<clean>, B<install-indep>, B<install-arch>,
B<install>, B<binary-arch>, B<binary-indep>, and B<binary>.

=head1 OVERRIDE AND HOOK TARGETS

A F<debian/rules> file using B<dh> can override the command that is run
at any step in a sequence, by defining an override target.  It is also
possible to inject a commands before or after any step without affecting
the step itself.

=head2 Injecting commands before or after a step

I<Note>: This feature requires debhelper 12.8 or later plus the package must
use compatibility mode 10 or later.

To inject commands before I<dh_command>, add a target named
B<execute_before_>I<dh_command> to the rules files.  Similarly, if you
want to inject commands after I<dh_command>, add the target
B<execute_after_>I<dh_command>.  Both targets can be used for the same
I<dh_command> and also even if the command is overridden (as described in
L</Overriding a command> below).

When these targets are defined, B<dh> will call the targets respectively
before or after it would invoke I<dh_command> (or its override target).

=head2 Overriding a command

To override I<dh_command>, add a target named B<override_>I<dh_command> to
the rules file. When it would normally run I<dh_command>, B<dh> will
instead call that target. The override target can then run the command with
additional options, or run entirely different commands instead. See
examples below.

=head2 Architecture dependent/independent override and hook targets

The override and hook targets can also be defined to run only
when building architecture dependent or architecture independent
packages. Use targets with names like B<override_>I<dh_command>B<-arch>
and B<execute_after>I<dh_command>B<-indep>.

This feature is available since debhelper 8.9.7 (for override targets)
and 12.8 (for hook targets).

=head2 Completely empty targets

As a special optimization, B<dh> will skip a target if it is completely empty.
This is mostly useful for override targets, where the command will simply be
skipped without the overhead of invoking a dummy target.

Note that the target has to be completely empty for this to work:

     # Skip dh_bar - the good and optimized way
     # Some rationale for skipping dh_bar goes here
     override_dh_bar:


     # Skip dh_foo - the slow way
     override_dh_foo:
        # Some rationale for skipping dh_foo goes here
        # (these comments causes a dummy target to be run)

=head2 Verifying targets are picked up by dh

If you want to confirm that B<dh> has seen an override or a hook target, you
can use the following command as an example:

    $ dh binary --no-act | grep dh_install | head -n5
         dh_installdirs
         dh_install
         debian/rules execute_after_dh_install
         dh_installdocs
         dh_installchangelogs

The B<debian/rules execute_after_dh_install> in the output, which signals
that B<dh> registered a B<execute_after_dh_install> target and would
run it directly after L<dh_install(1)>.

Note that L</Completely empty targets> will be omitted in the listing above.
This makes it a bit harder to spot as you are looking for the omission of
a command name.  But otherwise, the principle remains the same.

=head1 OPTIONS

=over 4

=item B<--with> I<addon>[B<,>I<addon> ...]

Add the debhelper commands specified by the given addon to appropriate places
in the sequence of commands that is run. This option can be repeated more
than once, or multiple addons can be listed, separated by commas.
This is used when there is a third-party package that provides
debhelper commands. See the F<PROGRAMMING> file for documentation about
the sequence addon interface.

A B<Build-Depends> relation on the package B<dh-sequence->I<addon>
implies a B<--with> I<addon>. This avoids the need for an explicit
B<--with> in F<debian/rules> that only duplicates what is already
declared via the build dependencies in F<debian/control>.  The
relation can (since 12.5) be made optional via e.g.
build-profiles.  This enables you to easily disable an addon that
is only useful with certain profiles (e.g. to facilitate
bootstrapping).

Since debhelper 12.5, addons can also be activated in B<indep>-only
mode (via B<Build-Depends-Indep>) or B<arch>-only mode (via
B<Build-Depends-Arch>). Such addons are only active in the particular
sequence (e.g. B<binary-indep>) which simplifies dependency
management for cross-builds.

Please note that addons activated via B<Build-Depends-Indep> or
B<Build-Depends-Arch> are subject to additional limitations to
ensure the result is deterministic even when the addon is
unavailable (e.g. during clean).  This implies that some addons
are incompatible with these restrictions and can only be used via
B<Build-Depends> (or manually via F<debian/rules>).  Currently,
such addons can only add commands to sequences.

=item B<--without> I<addon>

The inverse of B<--with>, disables using the given addon. This option
can be repeated more than once, or multiple addons to disable can be
listed, separated by commas.

=item B<--list>, B<-l>

List all available addons.

When called only with this option, B<dh> can be called from any
directory (i.e. it does not need access to files from a source
package).

=item B<--no-act>

Prints commands that would run for a given sequence, but does not run them.

Note that dh normally skips running commands that it knows will do nothing.
With --no-act, the full list of commands in a sequence is printed.

=back

Other options passed to B<dh> are passed on to each command it runs. This
can be used to set an option like B<-v> or B<-X> or B<-N>, as well as for more
specialised options.

=head1 EXAMPLES

To see what commands are included in a sequence, without actually doing
anything:

	dh binary-arch --no-act

This is a very simple rules file, for packages where the default sequences of
commands work with no additional options.

	#!/usr/bin/make -f
	%:
		dh $@

Often you'll want to pass an option to a specific debhelper command. The
easy way to do with is by adding an override target for that command.

	#!/usr/bin/make -f
	%:
		dh $@

	override_dh_strip:
		dh_strip -Xfoo

	override_dh_auto_configure:
		dh_auto_configure -- --with-foo --disable-bar

Sometimes the automated L<dh_auto_configure(1)> and L<dh_auto_build(1)>
can't guess what to do for a strange package. Here's how to avoid running
either and instead run your own commands.

	#!/usr/bin/make -f
	%:
		dh $@

	override_dh_auto_configure:
		./mondoconfig

	override_dh_auto_build:
		make universe-explode-in-delight

Another common case is wanting to do something manually before or
after a particular debhelper command is run.

	#!/usr/bin/make -f
	%:
		dh $@

	# Example assumes debhelper/12.8 and compat 10+
	execute_after_dh_fixperms:
		chmod 4755 debian/foo/usr/bin/foo

If you are on an older debhelper or compatibility level, the above
example would have to be written as.

	#!/usr/bin/make -f
	%:
		dh $@

	# Older debhelper versions or using compat 9 or lower.
	override_dh_fixperms:
		dh_fixperms
		chmod 4755 debian/foo/usr/bin/foo

Python tools are not run by dh by default, due to the continual change
in that area. Here is how to use B<dh_python2>.

	#!/usr/bin/make -f
	%:
		dh $@ --with python2

Here is how to force use of Perl's B<Module::Build> build system,
which can be necessary if debhelper wrongly detects that the package
uses MakeMaker.

	#!/usr/bin/make -f
	%:
		dh $@ --buildsystem=perl_build

Here is an example of overriding where the B<dh_auto_>I<*> commands find
the package's source, for a package where the source is located in a
subdirectory.

	#!/usr/bin/make -f
	%:
		dh $@ --sourcedirectory=src

And here is an example of how to tell the B<dh_auto_>I<*> commands to build
in a subdirectory, which will be removed on B<clean>.

	#!/usr/bin/make -f
	%:
		dh $@ --builddirectory=build

If your package can be built in parallel, please either use compat 10 or
pass B<--parallel> to dh. Then B<dpkg-buildpackage -j> will work.

	#!/usr/bin/make -f
	%:
		dh $@ --parallel

If your package cannot be built reliably while using multiple threads,
please pass B<--no-parallel> to dh (or the relevant B<dh_auto_>I<*>
command):


	#!/usr/bin/make -f
	%:
		dh $@ --no-parallel

Here is a way to prevent B<dh> from running several commands that you don't
want it to run, by defining empty override targets for each command.

	#!/usr/bin/make -f
	%:
		dh $@

	# Commands not to run:
	override_dh_auto_test override_dh_compress override_dh_fixperms:

A long build process for a separate documentation package can
be separated out using architecture independent overrides.
These will be skipped when running build-arch and binary-arch sequences.

	#!/usr/bin/make -f
	%:
		dh $@

	override_dh_auto_build-indep:
		$(MAKE) -C docs

	# No tests needed for docs
	override_dh_auto_test-indep:

	override_dh_auto_install-indep:
		$(MAKE) -C docs install

Adding to the example above, suppose you need to chmod a file, but only
when building the architecture dependent package, as it's not present
when building only documentation.

	# Example assumes debhelper/12.8 and compat 10+
	execute_after_dh_fixperms-arch:
		chmod 4755 debian/foo/usr/bin/foo

=head1 INTERNALS

If you're curious about B<dh>'s internals, here's how it works under the hood.

In compat 10 (or later), B<dh> creates a stamp file
F<debian/debhelper-build-stamp> after the build step(s) are complete
to avoid re-running them.  It is possible to avoid the stamp file by
passing B<--without=build-stamp> to B<dh>.  This makes "no clean"
builds behave more like what some people expect at the expense of
possibly running the build and test twice (the second time as root or
under L<fakeroot(1)>).

Inside an override target, B<dh_*> commands will create a log file
F<debian/package.debhelper.log> to keep track of which packages the
command(s) have been run for.  These log files are then removed once
the override target is complete.

In compat 9 or earlier, each debhelper command will record
when it's successfully run in F<debian/package.debhelper.log>. (Which
B<dh_clean> deletes.) So B<dh> can tell which commands have already
been run, for which packages, and skip running those commands again.

Each time B<dh> is run (in compat 9 or earlier), it examines the log,
and finds the last logged command that is in the specified
sequence. It then continues with the next command in the sequence.

A sequence can also run dependent targets in debian/rules.  For
example, the "binary" sequence runs the "install" target.

B<dh> uses the B<DH_INTERNAL_OPTIONS> environment variable to pass information
through to debhelper commands that are run inside override targets. The
contents (and indeed, existence) of this environment variable, as the name
might suggest, is subject to change at any time.

Commands in the B<build-indep>, B<install-indep> and B<binary-indep>
sequences are passed the B<-i> option to ensure they only work on
architecture independent packages, and commands in the B<build-arch>,
B<install-arch> and B<binary-arch> sequences are passed the B<-a>
option to ensure they only work on architecture dependent packages.

=cut

# Stash this away before init modifies it.
my @ARGV_orig=@ARGV;
my (@addons, @addon_requests);

# Reset umask to 0022 per #944691
umask(0022);

init(options => {
		"until=s" => \$dh{UNTIL},
		"after=s" => \$dh{AFTER},
		"before=s" => \$dh{BEFORE},
		"remaining" => \$dh{REMAINING},
		"with=s" => sub {
			my ($option, $value) = @_;
			push(@addon_requests, map { "+${_}" } split(",", $value));
		},
		"without=s" => sub {
			my ($option, $value) = @_;
			push(@addon_requests, map { "-${_}" } split(",", $value));
		},
		"l" => \&list_addons,
		"list" => \&list_addons,
	},
	# Disable complaints about unknown options; they are passed on to
	# the debhelper commands.
	ignore_unknown_options => 1,
	# Bundling does not work well since there are unknown options.
	bundling => 0,
	internal_parse_dh_sequence_info => 1,
	inhibit_log => 1,
);
set_buildflags();
reject_obsolete_params();

# If make is using a jobserver, but it is not available
# to this process, clean out MAKEFLAGS. This avoids
# ugly warnings when calling make.
if (is_make_jobserver_unavailable()) {
	clean_jobserver_makeflags();
}

# Process the sequence parameter.
my $sequence;
if (! compat(7)) {
	# From v8, the sequence is the very first parameter.
	$sequence=shift @ARGV_orig;
	if (defined $sequence && $sequence=~/^-/) {
		error "Unknown sequence $sequence (options should not come before the sequence)";
	}
}
else {
	# Before v8, the sequence could be at any position in the parameters,
	# so was what was left after parsing.
	$sequence=shift;
	if (defined $sequence) {
		@ARGV_orig=grep { $_ ne $sequence } @ARGV_orig;
	}
}
if (! defined $sequence) {
	error "specify a sequence to run";
}
# make -B causes the rules file to be run as a target.
# Also support completely empty override targets.
# Note: it's not safe to use rules_explicit_target before this check,
# since it causes dh to be run.
if ($sequence eq 'debian/rules' ||
    $sequence =~ /^override_dh_/ ||
    $sequence eq DUMMY_TARGET) {
	exit 0;
}


load_sequence_addon('root-sequence', SEQUENCE_TYPE_BOTH);


sub list_addons {
	my %addons;

	for my $inc (@INC) {
		require File::Spec;
		my $path = File::Spec->catdir($inc, "Debian/Debhelper/Sequence");
		if (-d $path) {
			for my $module_path (glob "$path/*.pm") {
				my $name = basename($module_path);
				$name =~ s/\.pm$//;
				$name =~ s/_/-/g;
				$addons{$name} = 1;
			}
		}
	}

	for my $name (sort keys %addons) {
		print "$name\n";
	}

	exit 0;
}


# The list of all packages that can be acted on.
my @packages=@{$dh{DOPACKAGES}};
my @arch_packages = getpackages("arch");
my @indep_packages = getpackages("indep");
my %sequence2packages = (
	'build-arch'   => \@arch_packages,
	'install-arch' => \@arch_packages,
	'binary-arch'  => \@arch_packages,

	'build-indep'   => \@indep_packages,
	'install-indep' => \@indep_packages,
	'binary-indep'  => \@indep_packages,

	'clean'   => \@packages,
	'build'   => \@packages,
	'install' => \@packages,
	'binary'  => \@packages,
);

my $sequence_unpack_flags = 0;

if ($sequence eq 'build-arch' ||
    $sequence eq 'install-arch' ||
    $sequence eq 'binary-arch') {
	push(@Debian::Debhelper::DH::SequenceState::options, "-a");
	# as an optimisation, remove from the list any packages
	# that are not arch dependent
	@packages = @{$sequence2packages{$sequence}};
}
elsif ($sequence eq 'build-indep' ||
       $sequence eq 'install-indep' ||
       $sequence eq 'binary-indep') {
	push(@Debian::Debhelper::DH::SequenceState::options, "-i");
	# ditto optimisation for arch indep
	@packages = @{$sequence2packages{$sequence}};
}

if (not @arch_packages) {
	$sequence_unpack_flags = FLAG_OPT_SOURCE_BUILDS_NO_ARCH_PACKAGES;
} elsif (not @indep_packages) {
	$sequence_unpack_flags = FLAG_OPT_SOURCE_BUILDS_NO_INDEP_PACKAGES;
}

@addons = compute_selected_addons($sequence, @addon_requests);

# Load addons, which can modify sequences.
foreach my $addon (@addons) {
	my $addon_name = $addon->{'name'};
	my $addon_type = $addon->{'addon-type'};
	load_sequence_addon($addon_name, $addon_type);
}

if (%Debian::Debhelper::DH::SequenceState::commands_added_by_addon) {
	while (my ($cmd, $addon) = each(%Debian::Debhelper::DH::SequenceState::commands_added_by_addon)) {
		my $addon_type = $addon->{'addon-type'};
		if ($addon_type eq 'indep') {
			unshift(@{$Debian::Debhelper::DH::SequenceState::command_opts{$cmd}}, '-i');
		} elsif ($addon_type eq 'arch') {
			unshift(@{$Debian::Debhelper::DH::SequenceState::command_opts{$cmd}}, '-a');
		}
	}
}


if (! exists($Debian::Debhelper::DH::SequenceState::sequences{$sequence})) {
	error("Unknown sequence $sequence (choose from: ".
		join(" ", sort(keys(%Debian::Debhelper::DH::SequenceState::sequences))).")");
}

parse_dh_cmd_options(@ARGV_orig);

# Figure out at what point in the sequence to start for each package.
my (%logged, %startpoint, $completed_sequences);

$completed_sequences = _check_for_completed_sequences(\%sequence2packages);

# In compat <= 8, the sequences are always inlined (those versions do not
# recurse into debian/rules anyway).  In compat 9+, we never inline an
# existing rules target.
my ($rules_targets, $full_sequence) = unpack_sequence(\%Debian::Debhelper::DH::SequenceState::sequences,
														$sequence,
														(!compat(8) ? 0 : 1),
														$completed_sequences,
														$sequence_unpack_flags,
														);
check_for_obsolete_commands($full_sequence);

%startpoint = compute_starting_point_in_sequences(\@packages, $full_sequence, \%logged);

for my $rules_command (@{$rules_targets}) {
	my $rules_target = extract_rules_target_name($rules_command)
		// error("Internal error: $rules_command was not a rules target!?");
	# Don't pass DH_ environment variables, since this is
	# a fresh invocation of debian/rules and any sub-dh commands.
	delete($ENV{DH_INTERNAL_OPTIONS});
	delete($ENV{DH_INTERNAL_OVERRIDE});
	run_sequence_command_and_exit_on_failure("debian/rules", $rules_target);
	my $override_packages = $sequence2packages{$rules_target} // \@packages;
	for my $package (@{$override_packages}) {
		my (undef, $seq) = unpack_sequence(\%Debian::Debhelper::DH::SequenceState::sequences, $rules_target, 1);
		COMMAND: for my $c (reverse(@{$seq})) {
			for my $j (0 .. $#{$full_sequence}) {
				if ($c eq $full_sequence->[$j]) {
					# Unfortunately, we do not guarantee any order
					# between the run targets.  Assuming e.g.
					# "install-arch" and "build" are opaque targets
					# then we could process "install-arch" first and
					# then "build".  In this case, it is important
					# that we do not "reset" the starting point for
					# "arch" packages.  Otherwise, we might repeat
					# part of the "install-arch" sequence when we
					# should not.
					$startpoint{$package} = $j + 1 if $j + 1 > $startpoint{$package};
					last COMMAND;
				}
			}
		}
	}
}

run_through_command_sequence($full_sequence, \%startpoint, \%logged,
	\@Debian::Debhelper::DH::SequenceState::options,
	\@packages, \@arch_packages, \@indep_packages);


sub _check_for_completed_sequences {
	my ($sequence2packages) = @_;
	my (%completed, %stamp_file_content);
	if ( -f BUILD_STAMP_FILE and not compat(9)) {
		open(my $fd, '<', BUILD_STAMP_FILE) or error("open(${\BUILD_STAMP_FILE}, ro) failed: $!");
		while (my $line = <$fd>) {
			chomp($line);
			$stamp_file_content{$line} = 1;
		}
		close($fd);
		my $build_indep_target_done = 1;
		my $build_arch_target_done = 1;
		for my $pkg (@{$sequence2packages->{'build-arch'}}) {
			if (not $stamp_file_content{$pkg}) {
				$build_arch_target_done = 0;
				last;
			}
		}
		for my $pkg (@{$sequence2packages->{'build-indep'}}) {
			if (not $stamp_file_content{$pkg}) {
				$build_indep_target_done = 0;
				last;
			}
		}
		$completed{'build-arch'} = 1 if $build_arch_target_done;
		$completed{'build-indep'} = 1 if $build_indep_target_done;
		$completed{'build'} = 1 if $build_indep_target_done and $build_arch_target_done;
	}
	return \%completed;
}


sub reject_obsolete_params {
	foreach my $deprecated ('until', 'after', 'before', 'remaining') {
		if (defined $dh{uc $deprecated}) {
			error("The --$deprecated option is not supported any longer (#932537). Use override targets instead.");
		}
	}
}


=head1 SEE ALSO

L<debhelper(7)>

This program is a part of debhelper.

=head1 AUTHOR

Joey Hess <joeyh@debian.org>

=cut