#!/bin/sh

# this is a wee bit expensive in terms of forks etc., compared to doing it in
# perl, but I wanted to show how *easy* it actually is now.  And really,
# you'll only notice if you access this repo like a hundred times a minute or
# something so don't sweat it.

# given a repo and a user, check if option('partialCopyOf') is set, and if so,
# fetch all allowed branches from there.

die() { echo "$@" >&2; exit 1; }

# make sure we're being called from the pre_git trigger
[ "$1" = "PRE_GIT" ] || die I must be called from PRE_GIT, not "$1"
shift

repo=$1
user=$2
main=`git config --file $GL_REPO_BASE/$repo.git/config --get gitolite.partialCopyOf`;
[ -z "$main" ] && exit 0

# "we", "our repo"  =>  the partial copy
# "main", "pco"     =>  the one which we are a "partial copy of"

cd $GL_REPO_BASE/$main.git

for ref in `git for-each-ref refs/heads '--format=%(refname)'`
do
    cd $GL_REPO_BASE/$repo.git

    gitolite access -q $repo $user R $ref &&
    git fetch -f $GL_REPO_BASE/$main.git $ref:$ref
done

export GL_BYPASS_ACCESS_CHECKS=1

# remove all refs not in main or accessible
cd $GL_REPO_BASE/$repo.git

for ref in `git for-each-ref refs/heads refs/tags '--format=%(refname)'`
do
    cd $GL_REPO_BASE/$main.git

    if git show-ref --verify --quiet $ref &&
       gitolite access -q $repo $user R $ref ; then
        # ref is present in main and accessible in repo
        continue
    fi

    git push -f $GL_REPO_BASE/$repo.git :$ref || die "FATAL: failed to delete $ref"
done

# remove all tags no longer reachable
cd $GL_REPO_BASE/$repo.git

for ref in `git for-each-ref refs/tags '--format=%(refname)'`
do
    SHA=`git rev-list -1 $ref`
    for branch in `git for-each-ref refs/heads '--format=%(refname)'`
    do
       if [ "`git merge-base $SHA $branch`" = "$SHA" ]; then
           # tag is reachable in current branch, continue higher loop
           continue 2
       fi
    done
    git push -f $GL_REPO_BASE/$repo.git :$ref || die "FATAL: failed to delete $ref"
done

exit 0