bin: delta: take the best parts out of check-warn

Take the best parts of check-warn to make a delta script for use with
other tools.

Signed-off-by: Randolph Sapp <[email protected]>

bin/delta.sh

@@ -0,0 +1,138 @@
+#!/bin/bash
+### Wrapper to calculate deltas between two commits
+
+
+HELP_STRING="
+Check if git branch or commit <NEW> generates any new build output running
+<COMMAND> based on git branch or commit <OLD>.
+
+check-warn.sh [OPTIONS]
+
+DIFF OPTIONS:
+  -a OLD             git branch or commit ID OLD as the base, 'HEAD' is
+                     acceptable
+  -b NEW             git branch or commit ID NEW for checking WARNING(s), 'HEAD'
+                     is acceptable
+  -m, --merge        automatically pick the merge-base for the given commits
+  --                 everything after this is the COMMAND to be executed
+
+OTHER OPTIONS:
+  -h, --help         this message
+"
+
+trap restore_branch 1 2 3 6 15
+
+usage()
+{
+	echo "${HELP_STRING}"
+	exit "$1"
+}
+
+save_branch()
+{
+	# get current branch name or commit ID
+	_cbr=$(git branch | sed -n '/\* /s///p')
+	if [[ "$_cbr" == "(HEAD detached"* ]]; then
+		_cbr=$(git rev-parse HEAD)
+	fi
+}
+
+restore_branch()
+{
+	[ -z "$_cbr" ] || git checkout "$_cbr"
+}
+
+summary()
+{
+	local _num
+
+	rm -f _new-warn.log
+	diff --changed-group-format="%>" --unchanged-group-format="" \
+		_a.log _b.log > _new-warn.log
+
+	_num=$(wc -l _new-warn.log)
+
+	echo
+	echo "Found $_num new build WARNING(s)."
+	echo
+
+	if [ "$_num" != "0" ]; then
+		cat _new-warn.log
+		exit 1
+	fi
+}
+
+generate_log()
+{
+	local git_hash log_name log_path
+
+	git_hash=$1
+	log_name=$2
+
+	log_path="${log_name}.log"
+
+	git checkout "${git_hash}" || exit 10
+
+	mkdir -p build
+
+	rm -f "${log_path}"
+	"${_cmd[@]}" 2>&1 | tee -a "${log_path}"
+}
+
+rev-parse()
+{
+	local rev
+	if ! rev=$(git rev-parse "$1"); then
+		printf '%s\n' 'Unable to parse given revisions:'
+		printf '  %s\n' "$1"
+		exit 2
+	fi
+	echo "$rev"
+}
+
+main()
+{
+	# do nothing if current workspace is not clean
+	if [ -n "$(git status --porcelain --untracked-files=no)" ]
+	then
+		echo "Error: Current workspace has uncommitted changes"
+		exit 4
+	fi
+
+	save_branch
+
+	_old=$(rev-parse "${_old}")
+	_new=$(rev-parse "${_new}")
+
+	if [ -n "${_merge}" ] && ! _old=$(git merge-base "${_old}" "${_new}")
+	then
+		echo "Error: Unable to find merge-base for the given commits"
+		exit 5
+	fi
+
+	generate_log "${_old}" "_a"
+	generate_log "${_new}" "_b"
+
+	restore_branch
+	summary
+}
+
+while [ "$#" -gt 0 ]; do
+	case $1 in
+	-h | --help) usage 0;;
+	-d | --device) shift; _dev=$1; shift;;
+	-o | --os) shift; _os=$1; shift;;
+	-a) shift; _old=$1; shift;;
+	-b) shift; _new=$1; shift;;
+	-m | --merge) shift; _merge=1;;
+	--) shift; break;;
+	*) shift;;
+	esac
+done
+_cmd=("$@")
+
+if [ -z "${_new}" ] || [ -z "${_old}" ] || [ -z "${_cmd[*]}" ]; then
+	usage 2
+fi
+
+main