Script to create and update an OpenWrt Mercurial mirror from its existing git trunk and branch mirrors

openwrt_mirror.sh

#!/bin/sh

branches="attitude_adjustment backfire"

# Destination repostiory location
destination=/var/hg/mirrors/openwrt

# Source repository locations
source_dir=/var/git/mirrors/openwrt
source_trunk="${source_dir}/trunk.git"
source_attitude_adjustment="${source_dir}/attitude_adjustment.git"
source_backfire="${source_dir}/backfire.git"

# Intermediate cache repositories
cache_dir=/home/mshroyer/openwrt_mirror
cache_git_combined="${cache_dir}/git_combined"
cache_hg_git="${cache_dir}/hg_git"
cache_convert="${cache_dir}/hg_convert"
cache_convert_branchmap="${cache_dir}/convert.branchmap"

# Commit IDs on the trunk repo to which each branch is anchored
parent_attitude_adjustment=684e620b003f605578e9bc575f09cfd8cb4ac9e2
parent_backfire=daa84485d8188ae882a985c39f062e6c3a8b1c92

# OpenWrt branch name
branch_name=openwrt

# Program names
git=/usr/local/bin/git
hg=/usr/local/bin/hg

fetch_git_combined() {
    if [ ! -d "${cache_git_combined}" ]; then
        $git clone "${source_trunk}" "${cache_git_combined}"
        cd "${cache_git_combined}"
        $git branch -m master trunk
        for branch in $branches; do
            branch_source=`eval "echo \\\$source_\${branch}"`
            $git remote add $branch $branch_source
            $git remote update $branch
            branch_root=`$git rev-list --max-parents=0 ${branch}/master`
            branch_parent=`eval "echo \\\$parent_\${branch}"`
            echo "${branch_root} ${branch_parent}" >>.git/info/grafts
            $git checkout -b $branch --no-track "${branch}/master"
        done
    else
        cd "${cache_git_combined}"
        $git checkout trunk
        $git pull
        for branch in $branches; do
            $git branch -D $branch
            $git remote update $branch
            $git checkout -b $branch --no-track "${branch}/master"
            $git checkout trunk
        done
    fi

    for branch in $branches; do
        branch_parent=`eval "echo \\\$parent_\${branch}"`
        $git filter-branch -f "${branch_parent}..${branch}"
    done
}

fetch_hg_git() {
    if [ ! -d "${cache_hg_git}" ]; then
        $hg clone -U "${cache_git_combined}" "${cache_hg_git}"
    else
        cd "${cache_hg_git}"
        $hg pull "${cache_git_combined}"
    fi
}

fetch_hg_convert() {
    cat >"${cache_convert_branchmap}" <<EOF
default $branch_name
EOF
    $hg convert --config convert.hg.tagsbranch=0 \
        --branchmap="${cache_convert_branchmap}" \
        "${cache_hg_git}" "${cache_convert}"
}

fetch_hg_clone() {
    if [ ! -d "${destination}" ]; then
        $hg clone -U -b $branch_name "${cache_convert}" "${destination}"
    else
        cd "${destination}"
        $hg pull -b $branch_name "${cache_convert}"
    fi
}

fetch_git_combined
fetch_hg_git
fetch_hg_convert
fetch_hg_clone