bin/repos: Add new working utility

This will be the base replacement for mr(1) (A.K.A. myrepos).  Instead
of having to feed what repositories to track or not manually to the
~/.mrconfig file, dynamically discover them with this new utility.

1 files changed, 187 insertions, 0 deletions

diff --git a/bin/repos b/bin/repos
new file mode 100755
index 0000000..27e0879
--- /dev/null
+++ b/bin/repos
@@ -0,0 +1,187 @@
+#!/bin/sh
+set -eu
+
+
+usage() {
+	cat <<-'EOF'
+		Usage:
+		  repos [-v] [DIRECTORY]
+		  repos -h
+	EOF
+}
+
+help() {
+	cat <<-'EOF'
+
+
+		Options:
+		  -v            enable verbose mode
+		  -h, --help    show this message
+
+		  DIRECTORY     the folder to traverse
+
+
+		Traverse DIRECTORY looking for VCS repositores.  As soon as
+		one is found, stop recursing, and emit its name alongside its
+		type.
+
+		On verbose mode, print the directories being visited.
+
+
+		Examples:
+
+		  Show all repositories under ~/dev/, excluding a few directories:
+
+		    $ repos -e ~/dev/go/ -e ~/dev/quicklisp/ ~/dev/
+		    # ...
+	EOF
+}
+
+
+for flag in "$@"; do
+	case "$flag" in
+		--)
+			break
+			;;
+		--help)
+			usage
+			help
+			exit
+			;;
+		*)
+			;;
+	esac
+done
+
+
+# Similar to urlencode but only for % and \n (and not \0).
+array_encode() {
+	sed 's/%/%25/g' | sed -e :a -e '$!N; s/\n/%0A/; ta'
+}
+
+array_decode() {
+	sed -e 's/%0A/\
+/g' -e 's/%25/%/g'
+}
+
+
+#
+# To avoid needing to keep decoding the array elements on every call to
+# `arr_includes`, assume directory names don't contain newlines.  This makes the
+# current code scanning ~/dev/ from 8 seconds go to 1 second.
+#
+
+arr_push() {
+	ARR="$1"
+	ELT="$2"
+	if [ -n "$ARR" ]; then
+		echo "$ARR"
+	fi
+	echo "$ELT" # | array_encode
+}
+
+arr_includes() {
+	ARR="$1"
+	ELT="$2"
+	echo "$ARR" | while read -r el; do
+		# if [ "$(printf '%s\n' "$el" | array_decode)" = "$ELT" ]; then
+		if [ "$el" = "$ELT" ]; then
+			return 2
+		fi
+	done
+	if [ $? = 2 ]; then
+		return 0
+	else
+		return 1
+	fi
+}
+
+EXCLUDE=
+VERBOSE=false
+while getopts 'e:vh' flag; do
+	case "$flag" in
+		e)
+			case "$OPTARG" in
+				*/)
+					ARG="$OPTARG"
+					;;
+				*)
+					ARG="$OPTARG/"
+					;;
+			esac
+			EXCLUDE="$(arr_push "$EXCLUDE" "$ARG")"
+			;;
+		v)
+			VERBOSE=true
+			;;
+		h)
+			usage
+			help
+			exit
+			;;
+		*)
+			usage >&2
+			exit 2
+			;;
+	esac
+done
+shift $((OPTIND - 1))
+
+
+is_repository() {
+	if [ -e "$1"/.git ]; then
+		printf 'git:%s\n' "$1"
+		return 0
+	elif [ -e "$1"/.hg ]; then
+		printf 'mercurial:%s\n' "$1"
+		return 0
+	elif [ -e "$1"/.bk ]; then
+		printf 'bitkeeper:%s\n' "$1"
+		return 0
+	elif [ -e "$1"/_darcs ]; then
+		printf 'darcs:%s\n' "$1"
+		return 0
+	elif [ -e "$1"/CVS/ ]; then
+		printf 'cvs:%s\n' "$1"
+		return 0
+	elif [ -e "$1"/"$(basename "$1")".fossil ]; then
+		printf 'fossil:%s\n' "$1"
+		return 0
+	fi
+	return 1
+}
+
+
+traverse_directory() {
+	if [ "$VERBOSE" = true ]; then
+		printf 'cur: %s\n' "$1" >&2
+	fi
+	if arr_includes "$EXCLUDE" "$1"; then
+		return
+	fi
+	if is_repository "$1"; then
+		return
+	fi
+	for d in "$1"/*; do
+		if [ "$VERBOSE" = true ]; then
+			printf 'cur: %s\n' "$d" >&2
+		fi
+		if [ ! -d "$d" ]; then
+			continue
+		fi
+		if arr_includes "$EXCLUDE" "$d/"; then
+			continue
+		fi
+		if ! is_repository "$d"; then
+			traverse_directory "$d"
+		fi
+	done
+}
+
+if [ -z "${1:-}" ]; then
+	set -- "$PWD"
+fi
+
+for dir in "$@"; do
+	traverse_directory "${dir%%/}"
+done