#!/usr/bin/env bash

#

# mirror script for Isabelle distribution or website

## diagnostics

PRG=`basename "$0"`

usage()

{

  echo

  echo "Usage: $PRG [OPTIONS] DEST"

  echo

  echo "  Options are:"

  echo "    -h    print help message"

  echo "    -n    dry run, don't do anything, just report what would happen"

  echo "    -w    (ignored for backward compatibility)"

  echo "    -d    delete files that are not on the server (BEWARE!)"

  echo

  exit 1

}

fail()

{

  echo "$1" >&2

  exit 2

}

## process command line

# options

HELP=""

ARGS=""

SRC="isabelle-website"

while getopts "hnwd" OPT

do

  case "$OPT" in

    h)

      HELP=true

      ;;

    n)

      ARGS="$ARGS -n"

      ;;

    w)

      echo "option -w ignored"

      ;;

    d)

      ARGS="$ARGS --delete"

      ;;

    \?)

      usage

      ;;

  esac

done

shift `expr $OPTIND - 1`

# help

if [ -n "$HELP" ]; then

  cat <<EOF

Mirroring the Isabelle distribution or website

==============================================

The Munich site maintains an rsync server for the Isabelle

distribution or website.

The rsync tool is very smart and efficient in mirroring large

directory hierarchies.  See http://rsync.samba.org/ for more

information.  The $PRG script provides a simple front-end

for easy access to the Isabelle distribution.

The script can be either run in conservative or clean-sweep mode.

1) Basic mirroring works like this:

  $PRG /foo/bar

where /foo/bar refers to your local copy of the Isabelle distribution

(the base directory has to exist already).  This operation is

conservative in the sense that files are never deleted, thus garbage

may accumulate over time as our master copy is changed.

Avoiding garbage in your local copy requires some care.  Rsync

provides a way to delete all additional local files that are absent in

the master copy.  This provides an efficient way to purge large

directory hierarchies, even unwillingly in case that a wrong

destination is given!

2a) This will invoke a safe dry-run of clean-sweep mirroring:

  $PRG -dn /foo/bar

where additions and deletions will be printed without any actual

changes performed so far.

2b) Exact mirroring with actual deletion of garbage may be performed

like this:

  $PRG -d /foo/bar

After gaining some confidence in the workings of $PRG one

would usually set up some automatic mirror scheme, e.g. a daily cron

job run by the 'nobody' user.

Add -w to the option list in order to mirror the whole Isabelle website

EOF

  exit 0

fi

# arguments

[ $# -ne 1 ] && { echo "Bad arguments: $*"; usage; }

DEST="$1"; shift;

## main

exec rsync -va $ARGS "rsync://isabelle.in.tum.de/$SRC" "$DEST/"