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#! /usr/bin/env bash
set -e -o pipefail
url=
rev=
expHash=
hashType=$NIX_HASH_ALGO
deepClone=$NIX_PREFETCH_GIT_DEEP_CLONE
leaveDotGit=$NIX_PREFETCH_GIT_LEAVE_DOT_GIT
fetchSubmodules=
builder=
branchName=$NIX_PREFETCH_GIT_BRANCH_NAME
# ENV params
out=${out:-}
http_proxy=${http_proxy:-}
# populated by clone_user_rev()
fullRev=
humanReadableRev=
commitDate=
commitDateStrict8601=
if test -n "$deepClone"; then
deepClone=true
else
deepClone=false
fi
if test "$leaveDotGit" != 1; then
leaveDotGit=
else
leaveDotGit=true
fi
usage(){
echo >&2 "syntax: nix-prefetch-git [options] [URL [REVISION [EXPECTED-HASH]]]
Options:
--out path Path where the output would be stored.
--url url Any url understand by 'git clone'.
--rev ref Any sha1 or references (such as refs/heads/master)
--hash h Expected hash.
--deepClone Clone the entire repository.
--no-deepClone Make a shallow clone of just the required ref.
--leave-dotGit Keep the .git directories.
--fetch-submodules Fetch submodules.
--builder Clone as fetchgit does, but url, rev, and out option are mandatory.
"
exit 1
}
argi=0
argfun=""
for arg; do
if test -z "$argfun"; then
case $arg in
--out) argfun=set_out;;
--url) argfun=set_url;;
--rev) argfun=set_rev;;
--hash) argfun=set_hashType;;
--branch-name) argfun=set_branchName;;
--deepClone) deepClone=true;;
--quiet) QUIET=true;;
--no-deepClone) deepClone=false;;
--leave-dotGit) leaveDotGit=true;;
--fetch-submodules) fetchSubmodules=true;;
--builder) builder=true;;
--help) usage; exit;;
*)
: $((++argi))
case $argi in
1) url=$arg;;
2) rev=$arg;;
3) expHash=$arg;;
*) exit 1;;
esac
;;
esac
else
case $argfun in
set_*)
var=${argfun#set_}
eval $var=$arg
;;
esac
argfun=""
fi
done
if test -z "$url"; then
usage
fi
init_remote(){
local url=$1
git init
git remote add origin "$url"
( [ -n "$http_proxy" ] && git config http.proxy "$http_proxy" ) || true
}
# Return the reference of an hash if it exists on the remote repository.
ref_from_hash(){
local hash=$1
git ls-remote origin | sed -n "\,$hash\t, { s,\(.*\)\t\(.*\),\2,; p; q}"
}
# Return the hash of a reference if it exists on the remote repository.
hash_from_ref(){
local ref=$1
git ls-remote origin | sed -n "\,\t$ref, { s,\(.*\)\t\(.*\),\1,; p; q}"
}
# Returns a name based on the url and reference
#
# This function needs to be in sync with nix's fetchgit implementation
# of urlToName() to re-use the same nix store paths.
url_to_name(){
local url=$1
local ref=$2
# basename removes the / and .git suffixes
local base
base=$(basename "$url" .git)
if [[ $ref =~ ^[a-z0-9]+$ ]]; then
echo "$base-${ref:0:7}"
else
echo "$base"
fi
}
# Fetch everything and checkout the right sha1
checkout_hash(){
local hash="$1"
local ref="$2"
if test -z "$hash"; then
hash=$(hash_from_ref "$ref")
fi
git fetch -t ${builder:+--progress} origin || return 1
git checkout -b "$branchName" "$hash" || return 1
}
# Fetch only a branch/tag and checkout it.
checkout_ref(){
local hash="$1"
local ref="$2"
if "$deepClone"; then
# The caller explicitly asked for a deep clone. Deep clones
# allow "git describe" and similar tools to work. See
# http://thread.gmane.org/gmane.linux.distributions.nixos/3569
# for a discussion.
return 1
fi
if test -z "$ref"; then
ref=$(ref_from_hash "$hash")
fi
if test -n "$ref"; then
# --depth option is ignored on http repository.
git fetch ${builder:+--progress} --depth 1 origin +"$ref" || return 1
git checkout -b "$branchName" FETCH_HEAD || return 1
else
return 1
fi
}
# Update submodules
init_submodules(){
# Add urls into .git/config file
git submodule init
# list submodule directories and their hashes
git submodule status |
while read -r l; do
local hash
local dir
local name
local url
# checkout each submodule
hash=$(echo "$l" | awk '{print substr($1,2)}')
dir=$(echo "$l" | awk '{print $2}')
name=$(
git config -f .gitmodules --get-regexp submodule\..*\.path |
sed -n "s,^\(.*\)\.path $dir\$,\\1,p")
url=$(git config --get "${name}.url")
clone "$dir" "$url" "$hash" ""
done
}
clone(){
local top=$PWD
local dir="$1"
local url="$2"
local hash="$3"
local ref="$4"
cd "$dir"
# Initialize the repository.
init_remote "$url"
# Download data from the repository.
checkout_ref "$hash" "$ref" ||
checkout_hash "$hash" "$ref" || (
echo 1>&2 "Unable to checkout $hash$ref from $url."
exit 1
)
# Checkout linked sources.
if test -n "$fetchSubmodules"; then
init_submodules
fi
if [ -z "$builder" ] && [ -f .topdeps ]; then
if tg help &>/dev/null; then
echo "populating TopGit branches..."
tg remote --populate origin
else
echo "WARNING: would populate TopGit branches but TopGit is not available" >&2
echo "WARNING: install TopGit to fix the problem" >&2
fi
fi
cd "$top"
}
# Remove all remote branches, remove tags not reachable from HEAD, do a full
# repack and then garbage collect unreferenced objects.
make_deterministic_repo(){
local repo="$1"
# run in sub-shell to not touch current working directory
(
cd "$repo"
# Remove files that contain timestamps or otherwise have non-deterministic
# properties.
rm -rf .git/logs/ .git/hooks/ .git/index .git/FETCH_HEAD .git/ORIG_HEAD \
.git/refs/remotes/origin/HEAD .git/config
# Remove all remote branches.
git branch -r | while read -r branch; do
git branch -rD "$branch" >&2
done
# Remove tags not reachable from HEAD. If we're exactly on a tag, don't
# delete it.
maybe_tag=$(git tag --points-at HEAD)
git tag --contains HEAD | while read -r tag; do
if [ "$tag" != "$maybe_tag" ]; then
git tag -d "$tag" >&2
fi
done
# Do a full repack. Must run single-threaded, or else we lose determinism.
git config pack.threads 1
git repack -A -d -f
rm -f .git/config
# Garbage collect unreferenced objects.
git gc --prune=all
)
}
_clone_user_rev() {
local dir="$1"
local url="$2"
local rev="${3:-HEAD}"
# Perform the checkout.
case "$rev" in
HEAD|refs/*)
clone "$dir" "$url" "" "$rev" 1>&2;;
*)
if test -z "$(echo "$rev" | tr -d 0123456789abcdef)"; then
clone "$dir" "$url" "$rev" "" 1>&2
else
echo 1>&2 "Bad commit hash or bad reference."
exit 1
fi;;
esac
pushd "$dir" >/dev/null
fullRev=$( (git rev-parse "$rev" 2>/dev/null || git rev-parse "refs/heads/$branchName") | tail -n1)
humanReadableRev=$(git describe "$fullRev" 2> /dev/null || git describe --tags "$fullRev" 2> /dev/null || echo -- none --)
commitDate=$(git show -1 --no-patch --pretty=%ci "$fullRev")
commitDateStrict8601=$(git show -1 --no-patch --pretty=%cI "$fullRev")
popd >/dev/null
# Allow doing additional processing before .git removal
eval "$NIX_PREFETCH_GIT_CHECKOUT_HOOK"
if test -z "$leaveDotGit"; then
echo "removing \`.git'..." >&2
find "$dir" -name .git -print0 | xargs -0 rm -rf
else
find "$dir" -name .git | while read -r gitdir; do
make_deterministic_repo "$(readlink -f "$gitdir/..")"
done
fi
}
clone_user_rev() {
if ! test -n "$QUIET"; then
_clone_user_rev "$@"
else
errfile="$(mktemp "${TMPDIR:-/tmp}/git-checkout-err-XXXXXXXX")"
# shellcheck disable=SC2064
trap "rm -rf \"$errfile\"" EXIT
_clone_user_rev "$@" 2> "$errfile" || (
status="$?"
cat "$errfile" >&2
exit "$status"
)
fi
}
json_escape() {
local s="$1"
s="${s//\\/\\\\}" # \
s="${s//\"/\\\"}" # "
s="${s//^H/\\\b}" # \b (backspace)
s="${s//^L/\\\f}" # \f (form feed)
s="${s//
/\\\n}" # \n (newline)
s="${s//^M/\\\r}" # \r (carriage return)
s="${s// /\\t}" # \t (tab)
echo "$s"
}
print_results() {
hash="$1"
if ! test -n "$QUIET"; then
echo "" >&2
echo "git revision is $fullRev" >&2
if test -n "$finalPath"; then
echo "path is $finalPath" >&2
fi
echo "git human-readable version is $humanReadableRev" >&2
echo "Commit date is $commitDate" >&2
if test -n "$hash"; then
echo "hash is $hash" >&2
fi
fi
if test -n "$hash"; then
cat <<EOF
{
"url": "$(json_escape "$url")",
"rev": "$(json_escape "$fullRev")",
"date": "$(json_escape "$commitDateStrict8601")",
"$(json_escape "$hashType")": "$(json_escape "$hash")",
"fetchSubmodules": $([[ -n "fetchSubmodules" ]] && echo true || echo false)
}
EOF
fi
}
if test -z "$branchName"; then
branchName=fetchgit
fi
if test -n "$builder"; then
test -n "$out" -a -n "$url" -a -n "$rev" || usage
mkdir -p "$out"
clone_user_rev "$out" "$url" "$rev"
else
if test -z "$hashType"; then
hashType=sha256
fi
# If the hash was given, a file with that hash may already be in the
# store.
if test -n "$expHash"; then
finalPath=$(nix-store --print-fixed-path --recursive "$hashType" "$expHash" "$(url_to_name "$url" "$rev")")
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 test -z "$finalPath"; then
tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/git-checkout-tmp-XXXXXXXX")"
# shellcheck disable=SC2064
trap "rm -rf \"$tmpPath\"" EXIT
tmpFile="$tmpPath/$(url_to_name "$url" "$rev")"
mkdir -p "$tmpFile"
# Perform the checkout.
clone_user_rev "$tmpFile" "$url" "$rev"
# Compute the hash.
hash=$(nix-hash --type $hashType --base32 "$tmpFile")
# Add the downloaded file to the Nix store.
finalPath=$(nix-store --add-fixed --recursive "$hashType" "$tmpFile")
if test -n "$expHash" -a "$expHash" != "$hash"; then
echo "hash mismatch for URL \`$url'. Got \`$hash'; expected \`$expHash'." >&2
exit 1
fi
fi
print_results "$hash"
if test -n "$PRINT_PATH"; then
echo "$finalPath"
fi
fi