Re: [PATCH]: New script for contrib

[Paolo Bonzini <bonzini at gnu dot org>]

Daniel Berlin wrote:
> This is a slight modification of the find-start-rev script that richard
> guenther sent me and i resent to gcc@.
>
> I'm sure somebody who actually does shell programming "for real" can
> make this better
>
>
>
> ------------------------------------------------------------------------
>
> 2005-10-31  Daniel Berlin  <dberlin@dberlin.org>
> 	    Richard Guenther <rguenther@suse.de>
>
> 	* svn-find-start-rev: New file.
> Index: svn-find-start-rev
> ===================================================================
> --- svn-find-start-rev	(revision 0)
> +++ svn-find-start-rev	(revision 0)
> @@ -0,0 +1,37 @@
> +# Find the version in which a repository path came into existence
> +
> +usage () {
> +cat <<EOF
> +  Usage:
> +      svn-find-start-rev  <url> <directory or file path in repository>
> +
> +      Example:
> +         svn-find-start-rev svn://gcc.gnu.org/svn/gcc branches/gcc-3_4-branch
> +EOF
> +exit 1
> +}
> +
> +test $# -lt 2 && usage
> +
> +rev=`svn info $1/trunk | grep '^Revision:' | sed -e 's/Revision: //'`
> +echo trunk is at rev $rev
> +width=$[$rev / 2]
> +rev=$[$rev - $width]
> +echo "Starting with $rev, $width"
> +while true; do
> +  width=$[$width / 2]
> +  echo svn info $1/$2@$rev
> +  svn info $1/$2@$rev 2>&1 | grep "Not a valid URL"
> +  if ! test $? == 0; then
> +    echo  - exists.
> +    rev=$[$rev - $width]
> +  else
> +    rev=$[$rev + $width]
> +  fi
> +  if test $width == 0; then
> +    break;
> +  fi
> +done
> +startrev=$[$rev + 1]
> +echo "$2 started at $rev"
> +

For the record, the two non portable constructs I see are

- you should use `expr ... ` instead of $[...]

- you should not use ! test $? == 0

  in this case, $? is not necessary at all

    if svn info $1/$2@$rev 2>&! | grep 'Not a valid URL'; then
      # grep succeeded
      rev=`expr $rev + $width`
    else
      # grep failed
      echo - exists.
      rev=`expr $rev - $width`
    fi

Paolo