#! /usr/bin/env perl
# Automatically compute some dependencies for the hand-written tests
# of the Automake testsuite.  Also, automatically generate some more
# tests from them (for particular cases/setups only).

# Copyright (C) 2011-2017 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/>.

#--------------------------------------------------------------------------

use warnings FATAL => "all";
use strict;
use File::Basename ();
use constant TRUE => 1;
use constant FALSE => 0;

my $me = File::Basename::basename $0;

# For use in VPATH builds.
my $srcdir = ".";

# The testsuite subdirectory, relative to the top-lever source directory.
my $testdir = "t";

# Where testsuite-related helper scripts, data files and shell libraries
# are placed.  Relative to the top-lever source directory.
my $testauxdir = "$testdir/ax";

#--------------------------------------------------------------------------

sub unindent ($)
{
  my $text = shift;
  $text =~ /^(\s*)/;
  my $indentation = $1;
  $text =~ s/^$indentation//gm;
  return $text;
}

sub atomic_write ($$;$)
{
  my ($outfile, $func) = (shift, shift);
  my $perms = @_ > 0 ? shift : 0777;
  my $tmpfile = "$outfile-t";
  foreach my $f ($outfile, $tmpfile)
    {
      unlink $f or die "$me: cannot unlink '$f': $!\n"
        if -e $f;
    }
  open (my $fh, ">$tmpfile")
    or die "$me: can't write to '$tmpfile': $!\n";
  $func->($fh);
  close $fh
    or die "$me: closing '$tmpfile': $!\n";
  chmod ($perms & ~umask, $tmpfile)
    or die "$me: cannot change perms for '$tmpfile': $!\n";
  rename ($tmpfile, $outfile)
    or die "$me: renaming '$tmpfile' -> '$outfile: $!\n'";
}

sub line_match ($$)
{
  my ($re, $file) = (shift, shift);
  # Try both builddir and srcdir, with builddir first, to play nice
  # with VPATH builds.
  open (FH, "<$file") or open (FH, "<$srcdir/$file")
    or die "$me: cannot open file '$file': $!\n";
  my $ret = 0;
  while (defined (my $line = <FH>))
    {
      if ($line =~ $re)
        {
          $ret = 1;
          last;
        }
    }
  close FH or die "$me: cannot close file '$file': $!\n";
  return $ret;
}

sub write_wrapper_script ($$$)
{
  my ($file_handle, $wrapped_test, $shell_setup_code, $creator_name) = @_;
  print $file_handle unindent <<EOF;
    #! /bin/sh
    # This file has been automatically generated.  DO NOT EDIT BY HAND!
    . test-lib.sh
    $shell_setup_code
    # In the spirit of VPATH, we prefer a test in the build tree
    # over one in the source tree.
    for dir in . "\$am_top_srcdir"; do
      if test -f "\$dir/$wrapped_test"; then
        echo "\$0: will source \$dir/$wrapped_test"
        . "\$dir/$wrapped_test"; exit \$?
      fi
    done
    echo "\$0: cannot find wrapped test '$wrapped_test'" >&2
    exit 99
EOF
}

sub get_list_of_tests ()
{
  my $make = defined $ENV{MAKE} ? $ENV{MAKE} : "make";
  # Unset MAKEFLAGS, for when we are called from make itself.
  my $cmd = "MAKEFLAGS= && unset MAKEFLAGS && cd '$srcdir' && "
            . "$make -s -f $testdir/list-of-tests.mk print-list-of-tests";
  my @tests_list = split /\s+/, `$cmd`;
  die "$me: cannot get list of tests\n" unless $? == 0 && @tests_list;
  my $ok = 1;
  foreach my $test (@tests_list)
    {
      # Respect VPATH builds.
      next if -f $test || -f "$srcdir/$test";
      warn "$me: test '$test' not found\n";
      $ok = 0;
    }
  die "$me: some test scripts not found\n" if !$ok;
  return @tests_list;
}

sub parse_options (@)
{
  use Getopt::Long qw/GetOptions/;
  local @ARGV = @_;
  GetOptions ('srcdir=s' => \$srcdir) or die "$me: usage error\n";
  die "$me: too many arguments\n" if @ARGV > 0;
  die "$me: srcdir '$srcdir': not a directory\n" unless -d $srcdir;
}

#--------------------------------------------------------------------------

my %deps_extractor =
  (
    libtool_macros =>
      {
        line_matcher => qr/^\s*required=.*\blibtool/,
        nodist_prereqs => "$testdir/libtool-macros.log",
      },
    gettext_macros =>
      {
        line_matcher => qr/^\s*required=.*\bgettext/,
        nodist_prereqs => "$testdir/gettext-macros.log",
      },
    pkgconfig_macros =>
      {
        line_matcher => qr/^\s*required=.*\bpkg-config/,
        nodist_prereqs => "$testdir/pkg-config-macros.log",
      },
    use_trivial_test_driver =>
      {
        line_matcher => qr/\btrivial-test-driver\b/,
        dist_prereqs => "$testauxdir/trivial-test-driver",
      },
    check_testsuite_summary =>
      {
        line_matcher => qr/\btestsuite-summary-checks\.sh\b/,
        dist_prereqs => "$testauxdir/testsuite-summary-checks.sh",
      },
    extract_testsuite_summary =>
      {
        line_matcher => qr/\bextract-testsuite-summary\.pl\b/,
        dist_prereqs => "$testauxdir/extract-testsuite-summary.pl",
      },
    check_tap_testsuite_summary =>
      {
        line_matcher => qr/\btap-summary-aux\.sh\b/,
        dist_prereqs => "$testauxdir/tap-summary-aux.sh",
      },
    on_tap_with_common_setup =>
      {
        line_matcher => qr/\btap-setup\.sh\b/,
        dist_prereqs => "$testauxdir/tap-setup.sh",
        nodist_prereqs => "$testdir/tap-common-setup.log",
      },
    depcomp =>
      {
        line_matcher => qr/\bdepcomp\.sh\b/,
        dist_prereqs => "$testauxdir/depcomp.sh",
      },
  );

#--------------------------------------------------------------------------

my %test_generators =
  (
    #
    # Any test script in the Automake testsuite that checks features of
    # the Automake-provided parallel testsuite harness might want to
    # define a sibling test that does similar checks, but for the old
    # serial testsuite harness instead.
    #
    # Individual tests can request the creation of such a sibling by
    # making the string "try-with-serial-tests" appear any line of the
    # test itself.
    #
    serial_testsuite_harness =>
      {
        line_matcher     => qr/\btry-with-serial-tests\b/,
        shell_setup_code => 'am_serial_tests=yes',
      },
    #
    # For each test script in the Automake testsuite that tests features
    # of one or more automake-provided shell script from the 'lib/'
    # subdirectory by running those scripts directly (i.e., not thought
    # make calls and automake-generated makefiles), define a sibling test
    # that does likewise, but running the said script with the configure
    # time $SHELL instead of the default system shell /bin/sh.
    #
    # A test is considered a candidate for sibling-generation if it calls
    # the 'get_shell_script' function anywhere.
    #
    # Individual tests can prevent the creation of such a sibling by
    # explicitly setting the '$am_test_prefer_config_shell' variable
    # to either "yes" or "no".
    # The rationale for this is that if the variable is set to "yes",
    # the test already uses $SHELL, so that a sibling would be just a
    # duplicate; while if the variable is set to "no", the test doesn't
    # support, or is not meant to use, $SHELL to run the script under
    # testing, and forcing it to do so in the sibling would likely
    # cause a spurious failure.
    #
    prefer_config_shell =>
      {
        line_matcher =>
          qr/(^|\s)get_shell_script\s/,
        line_rejecter =>
          qr/\bam_test_prefer_config_shell=/,
        shell_setup_code =>
          'am_test_prefer_config_shell=yes',
      },
  );

#--------------------------------------------------------------------------

parse_options @ARGV;

my @all_tests = get_list_of_tests;
my @generated_tests = (); # Will be updated later.

print "## -*- Makefile -*-\n";
print "## Generated by $me.  DO NOT EDIT BY HAND!\n\n";

print <<EOF;

## --------------------------------------------- ##
##  Autogenerated tests and their dependencies.  ##
## --------------------------------------------- ##

EOF

# A test script '$test' can possibly match more than one condition, so
# for each tests we need to keep a list of generated wrapper tests.
# Since what defines these wrapper scripts is the set of initializations
# that are issued before sourcing the original, wrapped tests, these
# initializations is what we put in our list entries.
# The list will be saved in the hash entry '$wrapper_setups{$test}'.
my %wrapper_setups = ();
foreach my $test (@all_tests)
  {
    my @setups = ('');
    foreach my $x (values %test_generators)
    {
      next
        if not line_match $x->{line_matcher}, $test;
      next
        if $x->{line_rejecter} and line_match $x->{line_rejecter}, $test;
      @setups = map { ($_, "$_\n$x->{shell_setup_code}") } @setups;
    }
    @setups = grep { $_ ne '' } @setups;
    $wrapper_setups{$test} = \@setups if @setups;
  }
# And now create all the wrapper tests.
for my $wrapped_test (sort keys %wrapper_setups)
  {
    my $setup_list = $wrapper_setups{$wrapped_test};
    (my $base = $wrapped_test) =~ s/\.([^.]*)$//;
    my $suf = $1 or die "$me: test '$wrapped_test' lacks a suffix\n";
    my $count = 0;
    foreach my $setup (@$setup_list)
      {
        $count++;
        my $wbase = "$base-w" . ($count > 1 ? $count : '');
        my $wrapper_test =  "$wbase.$suf";
        # Register wrapper test as "autogenerated".
        push @generated_tests, $wrapper_test;
        # Create wrapper test.
        atomic_write $wrapper_test,
                     sub { write_wrapper_script $_[0], $wrapped_test,
                                                $setup },
                     0444;
        # The generated test works by sourcing the original test, so that
        # it has to be re-run every time that changes ...
        print "$wbase.log: $wrapped_test\n";
        # ... but also every time the prerequisites of the wrapped test
        # changes.  The simpler (although suboptimal) way to do so is to
        # ensure that the wrapped tests runs before the wrapper one (in
        # case it needs to be re-run *at all*).
        # FIXME: we could maybe refactor the script to find a more
        # granular way to express such implicit dependencies.
        print "$wbase.log: $base.log\n";
      }
  }

print <<EOF;

## ---------------------------------------------------- ##
##  Ad-hoc autogenerated tests and their dependencies.  ##
## ---------------------------------------------------- ##

EOF

print "## Tests on automatic dependency tracking (see 'depcomp.sh').\n";

# Key: depmode, value: list of required programs.
my %depmodes =
  (
    auto         => ["cc"],
    disabled     => ["cc"],
    makedepend   => ["cc", "makedepend", "-c-o"],
    dashmstdout  => ["gcc"],
    cpp          => ["gcc"],
# This was for older (pre-3.x) GCC versions (newer versions
# have depmode "gcc3").  But other compilers use this depmode
# as well (for example, the IMB xlc/xlC compilers, and the HP
# C compiler, see 'lib/depcomp' for more info), so it's not
# obsolete, and it's worth giving it some coverage.
    gcc          => ["gcc"],
# This is for older (pre-7) msvc versions.  Newer versions
# have depmodes "msvc7" and "msvc7msys".
    msvisualcpp  => ["cl", "cygpath"],
    msvcmsys     => ["cl", "mingw"],
  );

foreach my $lt (TRUE, FALSE)
  {
    foreach my $m (sort keys %depmodes)
      {
        my $planned = ($lt && $m eq "auto") ? 84 : 28;
        my @required =
          (
            @{$depmodes{$m}},
            $lt ? ("libtoolize",) : (),
          );
        my @vars_init =
          (
            "am_create_testdir=empty",
            "depmode=$m",
            "depcomp_with_libtool=" . ($lt ? "yes" : "no"),
          );
        my $test = "$testdir/depcomp" . ($lt ? "-lt-" : "-") . "$m.tap";
        # Register wrapper test as "autogenerated" ...
        push @generated_tests, $test;
        # ... and create it.
        atomic_write ($test, sub
          {
            my $file_handle = shift;
            print $file_handle unindent <<EOF;
              #! /bin/sh
              # Automatically generated test.  DO NOT EDIT BY HAND!
              @vars_init
              required="@required"
              . test-init.sh
              plan_ $planned
              . depcomp.sh
              exit \$?
EOF
          },
          0444);
      }
   }

# Update generated makefile fragment to account for all the generated tests.
print "generated_TESTS =\n";
map { print "generated_TESTS += $_\n" } @generated_tests;

# The test scripts are scanned for automatic dependency generation *after*
# the generated tests have been created, so they too can be scanned.  To
# do so correctly, we need to update the list in '@all_tests' to make it
# comprise also the freshly-generated tests.

push @all_tests, @generated_tests;

print <<EOF;

## ----------------------------- ##
##  Autogenerated dependencies.  ##
## ----------------------------- ##

EOF

for my $k (sort keys %deps_extractor)
  {
    my $x = $deps_extractor{$k};
    my $dist_prereqs = $x->{dist_prereqs} || "";
    my $nodist_prereqs = $x->{nodist_prereqs} || "";
    my @tests = grep { line_match $x->{line_matcher}, $_ } @all_tests;
    map { s/\.[^.]*$//; s/$/\.log/; } (my @logs = @tests);
    print "## Added by deps-extracting key '$k'.\n";
    ## The list of all tests which have a dependency detected by the
    ## current key.
    print join(" \\\n  ", "${k}_TESTS =", @tests) . "\n";
    print "EXTRA_DIST += $dist_prereqs\n";
    map { print "$_: $dist_prereqs $nodist_prereqs\n" } @logs;
    print "\n";
  }

__END__