#! /bin/sh
##
## bison++.in: This file is part of build-aux.
## Copyright (C) 2006-2010, 2012, Gostai S.A.S.
##
## This software is provided "as is" without warranty of any kind,
## either expressed or implied, including but not limited to the
## implied warranties of fitness for a particular purpose.
##
## See the LICENSE file for more information.
##


# Exit status.
status=0

# Any tool failure is a failure of the script.
set -e

: ${BISON='@BISON@'}

stderr ()
{
  local i
  for i
  do
    echo "$i"
  done | sed >&2 -e "s/^/$me: /"
}

verbose ()
{
  if "$verbose"; then
    stderr "$@"
  fi
}

fatal ()
{
  stderr "$@"
  exit 1
}

usage ()
{
  cat <<EOF
usage: bison++ OPTIONS... -- INPUT OUTPUT BISON-OPTIONS

Options:
  -h, --help             display this message and exit successfully
  --location-dir=DIR     where to install position.hh and location.hh.
                         E.g., "\$(top_srcdir)/include/foo"
  --location-prefix=DIR  where #include must look for these headers.
                         E.g., "foo"
  --verbose              display diffs
EOF
  exit 0
}

me=$(basename $0)
fuse_switch='@abs_srcdir@/fuse-switch'
move_if_change='@abs_srcdir@/move-if-change --color'
verbose=false

## ---------------------- ##
## Command line parsing.  ##
## ---------------------- ##

get_options ()
{
  while test $# != 0
  do
    # Handle --option=value by splitting apart and putting back on argv.
    case $1 in
      (--*=*)
	opt=$(echo "$1" | sed -e 's/=.*//')
	val=$(echo "$1" | sed -e 's/[^=]*=//')
	shift
	set dummy "$opt" "$val" ${1+"$@"}; shift
	;;
    esac

    case $1 in
      (-h | --help   )    usage;;
      (--location-dir)    shift; location_dir=$1;;
      (--location-prefix) shift; location_prefix=$1/;;
      (--verbose)         verbose=:
                          move_if_change="$move_if_change --verbose";;
      (--) shift; break;;
      (*) fatal "invalid argument: $1";;
     esac
     shift
  done

  input=$1
  shift
  output=$1
  shift
  bisonflags="$@"
}


## ------ ##
## Main.  ##
## ------ ##

get_options "$@"

input_base=$(basename "$input")
input_dir=$(dirname "$input")

output_base=$(basename "$output")
output_base_noext=$(echo "$output_base" | sed -e 's/\.[^.]*//')
output_dir=$(dirname "$output")

: ${location_dir=$output_dir}

# The namespace we are in.
# FIXME: We need $srcdir to be able to compute it.
namespace=parser

if $BISON --xml --version >/dev/null 2>&1; then
  bisonflags="$bisonflags --xml"
fi

# Alexandre Duret-Lutz also notes that in VPATH-builds $(srcdir) can
# be an absolute path depending on how ./configure is called ...
# In that case

#   bison $(srcdir)/parsetiger.yy [...]

# will hard code the path in the maintainer's tree.  Hence, do not use
# paths with Bison, chdir there.

# A tmp dir.
tmp=$output_base_noext.dir
rm -rf $tmp
mkdir $tmp

# Compile in this dir.
# Don't use `ln -s' as its semantics of paths sucks.
cp $input $tmp
cd $tmp
set +e
$BISON $bisonflags $input_base -o $output_base
status=$?
set -e


# fix_bison_output FILE
# ---------------------
# Fixes in place.
fix_bison_output ()
{
  local file="$1"
  local base
  base=$(basename "$file")
  local base_noext
  base_noext=$(echo "$file" | sed -e 's/\..*//')
  perl -pi -e "
# Fix doxygen tags.
s|\Q\\file $base\E\b|\\\\file $namespace/$base|g;

# Fix sync lines for composite paths.
s|(^#line.*)$base_noext|\$1$input_dir/$base_noext|g;

# In case position.hh and location.hh were moved.
s{include \"(position.hh|location.hh)\"}
 {include <$location_prefix\$1>}g;

# Bison lacks a means to include headers in position.hh.
print <<EOF if \$ARGV =~ /position.hh/ && /namespace yy/;
# include <libport/symbol.hh>
# include <libport/windows.hh>
EOF

# Kill all the trailing blanks.
s/[ \t]+\$//;
"  "$1"

  # Fuse the switches of the parser.
  case $file in
    (*.cc) $fuse_switch $file
          # diff -uw $file.bak $file || true
          ;;
  esac
}

# compile_xml_file XML XSL OUT-EXT
# --------------------------------
# By transforming XML = FILE.xml with XSL.xsl, create FILE.OUT-EXT if needed.
# "Needed" means FILE.OUT-EXT does not exist, or XML was updated.
compile_xml_file ()
{
  local xml="$1"
  local xsl="$2.xsl"
  local out
  out=$(basename "$xml" ".xml").$3

  # "cmp NON-EXISTENT FILE" does what we want: fail.
  if ! cmp -s "$xml" "$(out "$xml")" \
      || test ! -f "$(out "$out")"; then
    local compile="xsltproc $($BISON --print-datadir)/xslt/$xsl"
    if ! $compile "$xml" >"$(tmp "$out")"; then
      stderr "cannot convert $xml report to $out"
      # Produce a stub for the HTML for sake of the Makefile.
      cat >"$(tmp "$out")" <<EOF
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
          "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html>
  <head>
    <title>Cannot run xsltproc</title>
  </head>
  <body>
    <p>Cannot run xsltproc</p>
  </body>
</html>
EOF
    fi
    install "$out"
  fi
}

# out FILE
# --------
# Return path name of FILE once installed in its destination directory.
out ()
{
  local f
  f=$(basename "$1")
  case $f in
    (position.hh|location.hh) echo "$location_dir/$f";;
    (*)                       echo "$output_dir/$f";;
  esac
}

# out FILE
# --------
# Return path name of FILE in the tmp directory.
tmp ()
{
  echo "$tmp/$(basename "$1")"
}

# install FILE
# ------------
# Install FILE in its destination directory.
install ()
{
  local dest
  dest=$(out "$1")
  local dir
  dir=$(dirname "$dest")
  mkdir -p "$dir" ||
    fatal "cannot create $dir"
  $move_if_change "$(tmp "$1")" "$dest"
}

# Go back to where we were and use relative paths instead of using
# absolute file names.  The messages look nicer.
cd ..
for file in $tmp/*
do
  base=$(basename $file)
  base_noext=$(echo "$base" | sed -e 's/\.[^.]*//')
  case $status:$base in
    (*:$input_base)
	# Leave it here.
	;;

    # Success or not, install it.
    (*:*.xml)
	# Computing the HTML is slow.  Do it when the XML changed.
	fix_bison_output "$file"
	compile_xml_file "$file" "xml2xhtml" "html"
	# Compiling the dot output is quite long, it would be better
	# to do that from the Makefile, so that -j applies.
	# compile_xml_file "$file" "xml2dot" "dot"
	install "$file"
	;;

    (0:*.hh)
	fix_bison_output "$file"
	# To save cycles, if the file differs only on sync lines,
	# update it (to be right), but keep the original timestamps.
	if test -r "$(out "$file")" &&
	   diff -I '^#line' -I '/\* Line .* of .*  \*/' -q \
                "$file" "$(out "$file")"
        then
	    touch -r "$(out "$file")" "$file"
	    cp "$(out "$file")" "$(out "$file").bak"
	    verbose "kept the stamps of $file"
	fi
	install "$file"
	;;

    (*:*.output)
	install "$file"
	;;

    (0:*)
	fix_bison_output "$file"
	install "$file"
	;;
  esac
done

# Get rid of the tmp dir.
rm -rf $tmp
exit $status