From 38ccce56602d353c2817bff0df3eb892592c0a19 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C2=B7=F0=90=91=91=F0=90=91=B4=F0=90=91=95=F0=90=91=91?=
 =?UTF-8?q?=F0=90=91=A9=F0=90=91=A4?= <toastal@posteo.net>
Date: Fri, 9 May 2025 18:17:27 +0700
Subject: [PATCH] nix-prefetch-pijul: init

---
 .../fetchpijul/nix-prefetch-pijul             | 137 ++++++++++++++++++
 .../nix-prefetch-scripts/default.nix          |   9 ++
 2 files changed, 146 insertions(+)
 create mode 100755 pkgs/build-support/fetchpijul/nix-prefetch-pijul

diff --git a/pkgs/build-support/fetchpijul/nix-prefetch-pijul b/pkgs/build-support/fetchpijul/nix-prefetch-pijul
new file mode 100755
index 000000000000..beffca26d31c
--- /dev/null
+++ b/pkgs/build-support/fetchpijul/nix-prefetch-pijul
@@ -0,0 +1,137 @@
+#!/bin/sh
+set -eu
+
+name="fetchpijul"
+remote=
+channel="main"
+change=
+state=
+exp_hash=
+
+usage() {
+	echo "Usage: nix-prefetch-pijul [options] [REMOTE] [STATE [EXPECTED-HASH]]"
+	echo
+	echo "Options:"
+	echo "	--name <NAME>        Symbolic store path name to use for the result."
+	echo "	--remote <REMOTE>    URL for the Pijul repository."
+	echo "	--change <CHANGE>    Clone a specific change."
+	echo "	--state <STATE>      Clone a specific state."
+	echo "	--channel <CHANNEL>  Channel name (default: ‘main’)."
+	echo "	--hash <HASH>        Expected hash."
+	echo "	--help               Show this help message."
+}
+
+# Argument parsing
+while [ $# -gt 0 ]; do
+	case "$1" in
+		--name)
+			name="$2"; shift 2 ;;
+		--remote)
+			remote="$2"; shift 2 ;;
+		--channel)
+			channel="$2"; shift 2 ;;
+		--change)
+			change="$2"; shift 2 ;;
+		--state)
+			state="$2"; shift 2 ;;
+		--hash)
+			exp_hash="$2"; shift 2 ;;
+		--help)
+			usage; exit 0 ;;
+		*)
+			# Positional arguments
+			if [ -z "$remote" ]; then
+				remote="$1"
+				shift
+			elif [ -z "$state" ]; then
+				state="$1"
+				shift
+			elif [ -z "$exp_hash" ]; then
+				exp_hash="$1"
+				shift
+			else
+				echo "Error: Too many arguments" >&2
+				usage
+				exit 1
+			fi
+			;;
+	esac
+done
+
+if [ -z "$remote" ]; then
+	echo "Error: URL for remote is required." >&2
+	echo >&2
+	usage
+	exit 1
+elif [ -n "$change" -a -n "$state" ]; then
+	echo "Error: Only one of ‘change’ or ‘state’ can be set" >&2
+	echo >&2
+	usage
+	exit 1
+fi
+
+hash=
+hash_algo="${NIX_HASH_ALGO:-"sha256"}"
+hash_format="${hashFormat:-"--base32"}"
+final_path=
+
+# If the hash was given, a file with that hash may already be in the
+# store.
+if [ -n "$exp_hash" ]; then
+	final_path=$(nix-store --print-fixed-path --recursive "$hash_algo" "$exp_hash" "$name")
+	if ! nix-store --check-validity "$final_path" 2> /dev/null; then
+		final_path=""
+	fi
+	hash="$exp_hash"
+fi
+
+# If we don’t know the hash or a path with that hash doesn’t exist,
+# download the file and add it to the store.
+if [ -z "$final_path" ]; then
+	tmp_clone="$(realpath "$(mktemp -d --tmpdir pijul-clone-tmp-XXXXXXXX)")"
+	trap "rm -rf \"$tmp_clone\"" EXIT
+
+	clone_args="--channel $channel"
+	if [ -n "$change" ]; then
+		clone_args="$clone_args --change $change"
+	elif [ -n "$state" ]; then
+		clone_args="$clone_args --state $state"
+	fi
+
+	cd "$tmp_clone"
+	pijul clone $clone_args "$remote" "$name"
+	rm -rf "$tmp_clone/$name/.pijul"
+
+	hash="$(nix-hash --type "$hash_algo" "$hash_format" "$tmp_clone/$name")"
+	final_path=$(nix-store --add-fixed --recursive "$hash_algo" "$tmp_clone/$name")
+
+	if [ -n "$exp_hash" -a "$exp_hash" != "$hash" ]; then
+		echo "Hash mismatch for “$remote” @ “$channel”" >&2
+		echo "Expected: $exp_hash" >&2
+		echo "Got:      $hash" >&2
+		exit 1
+	fi
+fi
+
+json_escape() {
+	printf '%s' "$1" | jq -Rs .
+}
+
+cat <<EOF
+{
+	"remote": $(json_escape "$remote"),
+	"channel": $(json_escape "$channel"),
+EOF
+if [ -n "$change" ]; then cat <<EOF
+	"change": "$(json_escape "$change")",
+EOF
+elif [ -n "$state" ]; then cat <<EOF
+	"state": "$(json_escape "$state")",
+EOF
+fi; cat <<EOF
+	"path": "$final_path",
+	$(json_escape "$hash_algo"): $(json_escape "$hash"),
+	"hash": "$(nix-hash --to-sri --type "$hash_algo" "$hash")"
+}
+EOF
+# vim: noet ci pi sts=0
diff --git a/pkgs/tools/package-management/nix-prefetch-scripts/default.nix b/pkgs/tools/package-management/nix-prefetch-scripts/default.nix
index 8c88fcb6bb30..158d18d70cc9 100644
--- a/pkgs/tools/package-management/nix-prefetch-scripts/default.nix
+++ b/pkgs/tools/package-management/nix-prefetch-scripts/default.nix
@@ -5,6 +5,7 @@
   buildEnv,
   bash,
   breezy,
+  cacert,
   coreutils,
   cvs,
   findutils,
@@ -12,7 +13,9 @@
   git,
   git-lfs,
   gnused,
+  jq,
   mercurial,
+  pijul,
   subversion,
 }:
 
@@ -73,6 +76,11 @@ rec {
   nix-prefetch-svn = mkPrefetchScript "svn" ../../../build-support/fetchsvn/nix-prefetch-svn [
     subversion
   ];
+  nix-prefetch-pijul = mkPrefetchScript "pijul" ../../../build-support/fetchpijul/nix-prefetch-pijul [
+    pijul
+    cacert
+    jq
+  ];
 
   nix-prefetch-scripts = buildEnv {
     name = "nix-prefetch-scripts";
@@ -83,6 +91,7 @@ rec {
       nix-prefetch-git
       nix-prefetch-hg
       nix-prefetch-svn
+      nix-prefetch-pijul
     ];
 
     meta = with lib; {