#!/bin/sh
# Check for files in directory $1 being up to date, according to the
# list on stdin.  Don't actually make any changes, just show the diffs.
#
# Empty (or only whitespace) input lines are ignored.
# Lines beginning with # are ignored.
# Lines with just one word are ignored.
# Otherwise, the line has two or more whitespace-separated words:
#   the first word is the source directory, which can be a top-level
#   directory of source archive,
#   the second word is the source file name relative to the source
#   directory, and
#   the third word is the destination, other optional words are
#   options.
# The possible options are "gpl" (to replace the license with the GPL)
#   and "doclicense" (to replace @include doclicense.texi with fdl.texi)
#   and "release" (to use the release version instead of the
#   development version).
#   Unrecognized options are ignored.
# $VARIABLE expansions are done (with sh eval).
#
# This script is used in gnulib and texinfo; the input files are named
# srclist.txt.
#
# Copyright (C) 2002-2003, 2005, 2007-2018 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 3 of the License, 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/>.

# Originally written by Karl Berry.


if test -n "$1"; then
  cd "$1" || exit 1
fi

verbose=false
#chicken="echo (would)"

: ${TMPDIR=/tmp}
dsttmp=$TMPDIR/srclist.dst

# Source `dirname $0`/srclistvars.sh first, if it exists.
mydir=`dirname $0`
test -r $mydir/srclistvars.sh && . $mydir/srclistvars.sh


# 
# sed command to fix the license to be GPL.
fixlicense='
  /^[[:space:]]*#[[:space:]]*Th[ei][ s].* is free software/,/^[[:space:]]*#.*USA\./c\
#   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 3 of the License, 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/>.

  /Th[ei][ s].* is free software/,/\*\//c\
   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 3 of the License, 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/>.  */
'

# sed command to remove lines containing $Id lines.
# Quote the $ so that CVS does not expand it in this script.
remove_id_lines='/[$]Id:.*[$]/d'

# $1 is the root directory of input file, $2 is input file, $3 is
# output.  Remove $Id lines, since they'll differ between source
# locations.  If $options contains "gpl", change the license to be the
# standard GPL.  We use this for libc files, et al.
#
fixfile() \
{
  sed_command="$remove_id_lines"

  case " $options " in
  *' gpl '*)
    sed_command="$sed_command; $fixlicense";;

  *' doclicense '*)
    sed_command="$sed_command; s/@include doclicense.texi/@include fdl.texi/";;
  esac

  sed "$sed_command" $1 >$2-t && mv $2-t $2
}


# 
cat | while read top src dst options; do
  #echo "top=$top, src=$src, dst=$dst, options=$options" >&2
  case $top:$src:$dst in
    *: ) continue;;    # skip lines without last element
    '#'* ) continue;;  # skip comment-only lines
  esac

  release=false
  case " $options " in
    *' release '*)
      release=true
      ;;
  esac

  eval top=$top
  if $release && test ! -d $top/.git; then
    echo "$0: 'release' option only works with git checkout"
    release=false
  fi

  # Expand variables and make sure we have an input file.
  src1=$src
  eval src=$top/$src
  if test ! -r $src; then
    echo "$0: cannot read $src" >&2
    continue
  fi

  # Ignore subdirs in src dir.  E.g., if input spec is
  #   src/subdir/foo.c dst
  # then write destination file dst/foo.c.
  eval dst=$dst
  test -d $dst && dst=$dst/`basename $src`

  if $release; then
    rev=$(git --git-dir=$top/.git describe --abbrev=0)
    reltmp=$TMPDIR/`basename $src1`:$rev
    git --git-dir=$top/.git show $rev:$src1 > $reltmp
    fixfile $reltmp $reltmp
  fi

  # Fix files in both src and dst, for the sake
  # of a clean comparison.
  srctmp=$TMPDIR/`basename $src`
  fixfile $src $srctmp
  test -r $dst && fixfile $dst $dsttmp

  # if src was executable, make dst executable, to placate git.
  test -x $src && chmod a+x $dst

  if test ! -e $dst; then
    echo "## $srctmp $dst  # new"
    $chicken cp -p $srctmp $dst
  elif $release && cmp -s $reltmp $dsttmp; then
    $verbose && echo "## $reltmp $dst  # unchanged"
  elif cmp -s $srctmp $dsttmp; then
    $verbose && echo "## $srctmp $dst  # unchanged"
  else
    echo "## $srctmp $dst  # changes"
    diff -C 2 $dst $srctmp
  fi
done

rm -f $dsttmp