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Data management tools for playing BattleTech
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127#!/usr/bin/env bash# Fetch and unpack a MegaMek release, which is the thing this repository reads# and deliberately does not contain.## ./scripts/fetch-megamek.sh 0.51.0# ./scripts/fetch-megamek.sh 0.51.0 /somewhere/else## Prints the install path on stdout, so it composes:## MM_HOME="$(./scripts/fetch-megamek.sh 0.51.0)"## It gets you the unit files, the art and the jar. It does not get you the# equipment catalogue: that is computed when MegaMek loads, comes out through# bridge/dump.sh, and needs a container. Every command here that prices a# design needs both, and says so.## The digest is not optional and not ours to invent. Upstream publishes none,# so the table below holds digests taken from a fetch that was checked twice,# and a version that is not in it needs one passed in rather than being# trusted:## HELM_MEGAMEK_SHA256=<digest> ./scripts/fetch-megamek.sh 0.52.0## arena pins the same release for the container a match runs in, in its# versions.env, and the digest here for 0.51.0 is that one. When they differ,# the match and the library are describing different games.set -euo pipefail
usage() { echo "usage: scripts/fetch-megamek.sh <version> [install-dir]"}
# Releases this repository has been run against, and the digest of each# release tarball. Add a line when a version is taken, from a fetch you trust.sha256_for() { case "$1" in 0.51.0) echo "5d673cdaca0ead0e58d6e74db5b2d1e06bc25ccb5caaf332dad71624f6487b85" ;; *) echo "" ;; esac}
version="${1:-}"if [ -z "$version" ]; then usage >&2 exit 2fiif [ "$version" = "-h" ] || [ "$version" = "--help" ]; then usage exit 0fi
cache="${XDG_CACHE_HOME:-$HOME/.cache}/helm/megamek"dest="${2:-$cache/$version}"mkdir -p "$cache"
# Already unpacked: say where and stop. The tree is 590MB and a release's bytes# never change, so re-fetching one is only ever wasted time.if [ -f "$dest/MegaMek.jar" ] && [ -d "$dest/data/mekfiles" ]; then echo "already unpacked" >&2 echo "$dest" exit 0fi
sha256="${HELM_MEGAMEK_SHA256:-$(sha256_for "$version")}"[ -n "$sha256" ] || { echo "no digest known for MegaMek $version." >&2 echo " Upstream publishes none, so take one from a fetch you trust and pass it:" >&2 echo " HELM_MEGAMEK_SHA256=<digest> $0 $version" >&2 echo " then add it to sha256_for() in this script." >&2 exit 1}
url="https://github.com/MegaMek/megamek/releases/download/v${version}/MegaMek-${version}.tar.gz"tarball="$cache/MegaMek-${version}.tar.gz"
# Kept, and checked whether it was kept or fetched. The release is 639MB and# the check is what makes a cached copy safe to believe.if [ -f "$tarball" ] && echo "$sha256 $tarball" | sha256sum -c --status -; then echo "using $tarball" >&2else echo "fetching $url" >&2 # A progress meter for a person watching 609MB arrive, and nothing at all # when this is a step inside something else. quiet="" [ -t 2 ] || quiet="-s" # To a partial name, moved into place only once the digest checks, so an # interrupted download is never mistaken for a release. # shellcheck disable=SC2086 # $quiet is one flag or nothing, deliberately curl -fSL $quiet --retry 3 --retry-connrefused -o "$tarball.part" "$url" if ! echo "$sha256 $tarball.part" | sha256sum -c --status -; then rm -f "$tarball.part" echo "digest mismatch for MegaMek $version" >&2 echo " expected $sha256" >&2 echo " refusing to unpack a tarball that is not the pinned release" >&2 exit 1 fi mv "$tarball.part" "$tarball"fi
# Upstream's tarball does not spell the version the way the tag does — 0.51.0# unpacks as MegaMek-0.51.00 — so the directory is found rather than assumed.staging="$(mktemp -d "$cache/unpack.XXXXXX")"trap 'rm -rf "$staging"' EXITtar -xzf "$tarball" -C "$staging"root="$(find "$staging" -maxdepth 1 -type d -name 'MegaMek-*' | head -1)"[ -n "$root" ] || { echo "no MegaMek-* directory in the tarball; upstream changed its layout" >&2 exit 1}
mkdir -p "$(dirname "$dest")"rm -rf "$dest"mv "$root" "$dest"
echo "unpacked MegaMek $version into $dest" >&2echo >&2echo "Reading the library needs nothing else:" >&2echo " cargo build --release" >&2echo " ./target/release/helm art --megamek $dest --out art.json" >&2echo >&2echo "Anything that prices a design also needs the equipment catalogue, which" >&2echo "MegaMek computes at load time. That is what the bridge is for, and it" >&2echo "runs a JDK in a container:" >&2echo " ./bridge/dump.sh $dest /tmp/helm-bridge" >&2echo " ./target/release/helm index --megamek $dest --bridge-dir /tmp/helm-bridge --out units.json" >&2echo "$dest"