Add install buf script

dot_local/bin/executable_install-buf

@@ -0,0 +1,56 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+# shellcheck disable=SC1090
+source "${XDG_DATA_HOME}/buddy-up/includes/utils.sh"
+
+VERSION=${VERSION:-v1.26.1}
+DEST=${XDG_DATA_HOME}/apps/releases/buf
+CURRENT=${DEST}/current
+URL=https://github.com/bufbuild/buf/releases/download/${VERSION}/buf-$(uname)-$(uname -m).tar.gz
+
+main () (
+	extract_tarball "${URL}" "${DEST}/${VERSION}" "--strip-components 1"
+	set_current_link "${DEST}" "${VERSION}"
+
+	symlink_apps
+	symlink_man_pages
+
+	set_symlink \
+		"${XDG_CONFIG_HOME}/bash/bashrc.d" buf.sh \
+		"${CURRENT}/etc/bash_completion.d" buf
+	set_symlink "${XDG_DATA_HOME}/zsh/site-functions" _buf \
+		"${CURRENT}/share/zsh/site-functions" _buf
+	set_symlink "${XDG_DATA_HOME}/fish/vendor_completions.d" buf.fish \
+		"${CURRENT}/share/fish/vendor_completions.d" buf.fish
+)
+
+symlink_apps () (
+	APPS=$(find "${DEST}/${VERSION}/bin" -type f -exec basename {} ';')
+	for APP in ${APPS}; do
+		set_symlink "${XDG_BIN_HOME}" "${APP}" "${CURRENT}/bin" "${APP}"
+	done
+)
+
+symlink_man_pages () (
+	MANS=$(find "${DEST}/${VERSION}/share/man/man1" -type f -exec basename {} ';')
+	for SHARE in ${MANS}; do
+		set_symlink "${MAN_DIR}" "${SHARE}" "${CURRENT}/share/man/man1" "${SHARE}"
+	done
+)
+
+set_symlink () (
+	dest_dir=$1
+	dest_file=$2
+	src_dir=$3
+	src_file=$4
+
+	mkdir_if_missing "${dest_dir}"
+	cd "${dest_dir}" || exit 1
+	unlink_if_set "${dest_dir}/${dest_file}"
+	ln -s "$(relative_path "${dest_dir}" "${src_dir}/${src_file}")" "${dest_file}"
+	cd - > /dev/null || exit 1
+)
+
+main "$@"