util: add visitor pattern for scrubbing json These functions are for future patches that will add safer serialization via json. '_convert' is a visitor pattern that will be used for lists, dictionaries, and strings for helping convert None to the empty string since json forbids 'null' as a key for a dictionary. None -> '' is a safe mapping because this is for the 'branch_info' variable which already maps the empty string to None. Note, also, that json is chosen instead of, say, csv because json has a concept of 'null' and will better handle utf8 strings (which subversion supports). Important: this changes the requirement of hgsubversion to python 2.6+.

function verify_current_revision()
{
    /bin/rm -rf *
    exportcmd="svn export `hg svn info 2> /dev/null | grep '^URL: ' | sed 's/URL: //'`@`hg svn info | grep ^Revision | sed 's/.*: //;s/ .*//'` . --force"
    `echo $exportcmd` > /dev/null
    x=$?
    if [[ "$x" != "0" ]] ; then
        echo $exportcmd
        echo 'export failed!'
        return 255
    fi
    if [[ "`hg st | wc -l | python -c 'import sys; print sys.stdin.read().strip()'`" == "0" ]] ; then
        return 0
    else
        if [[ $1 != "keep" ]] ; then
            revert_all_files
        fi
        return 1
    fi
}

function revert_all_files()
{
    hg revert --all
    hg purge
}