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core/pkgs/build-support/fetchhg/nix-prefetch-hg
2024-05-13 11:34:52 -04:00

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#! /usr/bin/env bash
set -e
url=$1
rev=$2
expHash=$3
hashType="${NIX_HASH_ALGO:-sha256}"
hashFormat=${hashFormat:-"--base32"}
rev="${rev:-tip}"
LOG() {
echo "$@" >&2
}
die() {
LOG "$@"
exit 1
}
if [[ -z "$url" || "$url" == "--help" ]]; then
die "Usage: nix-prefetch-hg URL [rev [EXPECTED-HASH]]"
fi
if [[ "${fetchSubrepos:-0}" == 1 ]]; then
subrepoClause=S
else
subrepoClause=
fi
# If the hash was given, a file with that hash may already be in the
# store.
if [[ -n "$expHash" ]]; then
finalPath=$(nix-store --print-fixed-path --recursive "$hashType" "$expHash" hg-archive)
if ! nix-store --check-validity "$finalPath" 2> /dev/null; then
finalPath=
fi
hash="$expHash"
fi
# If we don't know the hash or a path with that hash doesn't exist,
# download the file and add it to the store.
if [[ -z "$finalPath" ]]; then
tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/hg-checkout-tmp-XXXXXXXX")"
cleanup() { x=$?; rm -rf "$tmpPath"; exit $x; }; trap cleanup EXIT
tmpArchive="$tmpPath/hg-archive"
# Perform the checkout.
if [[ "$url" != /* ]]; then
tmpClone="$tmpPath/hg-clone"
hg clone -q -y -U "$url" "$tmpClone" >&2
else
tmpClone=$url
fi
hg archive -q$subrepoClause -y -r "$rev" --cwd "$tmpClone" "$tmpArchive"
rm -f "$tmpArchive/.hg_archival.txt"
LOG "hg revision is $(cd "$tmpClone"; hg id -r "$rev" -i)"
# Compute the hash.
hash=$(nix-hash --type "$hashType" "$hashFormat" "$tmpArchive")
if [[ -z "$QUIET" ]]; then LOG "hash is $hash"; fi
# Add the downloaded file to the Nix store.
finalPath=$(nix-store --add-fixed --recursive "$hashType" "$tmpArchive")
if [[ -n "$expHash" && "$expHash" != "$hash" ]]; then
die "ERROR: hash mismatch for URL \`$url'"
fi
fi
if [[ -z "$QUIET" ]]; then LOG "path is $finalPath"; fi
echo "$hash"
if [[ -n "$PRINT_PATH" ]]; then
echo "$finalPath"
fi