New multiconfig design

1 files changed, 119 insertions, 0 deletions

diff --git a/lib/utils b/lib/utils
new file mode 100644
index 0000000..5281d19
--- /dev/null
+++ b/lib/utils
@@ -0,0 +1,119 @@
+# vim: ft=sh
+
+die() {
+	echo "$@" >&2
+	kill $$
+}
+
+# Returns name of this module
+module_id() {
+	$(basename "$0")
+}
+
+# Status file for this module
+MC_STATUS_FILE="$MC_STATUS_DIR/$(module_id)"
+
+# Return hash of given file from status file
+# First argument have to be a path to output file
+installed_hash() {
+	awk -F '\t' -v regex="^$1$" '/$2 ~ regex { print $1 }' "$MC_STATUS_FILE"
+}
+
+# Hash of currently installed file
+# Access remote resource
+# It connects to remote server and requests resource for given plugin.
+# It expects only one argument and that is resource identifier.
+remote_source() {
+	local res="$1"
+	local mod_id="$(module_id)"
+	if [ -n "$MC_LOCAL_DIR" ]; then
+		"$MC_LOCAL_DIR/request.sh" "$mod_id:$res"
+	else
+		ssh -i ~/.ssh/multiconfig multiconfig@cynerd.cz -- "$mod_id:$res"
+	fi
+}
+
+# Defined and create QUEUE file for this instance
+MC_QUEUE_FILE="$(mktemp multiconfig-$(module_id).queue.XXXXXX)"
+touch "$MC_QUEUE_FILE"
+
+# Variable signaling if file was updated or not
+change=false
+
+# Install given file
+# First argument has to be a identifier string for remote script
+# Second argument has to be an output file (absolute path).
+inst() {
+	local src="$1"
+	local out="$2"
+	[ -f "$MC_QUEUE_FILE" ] || die "inst can be called only before apply call!"
+	grep -q "\t$out$" || die "inst can be called on one output only once!"
+	# TODO verify that this output is not already in queue
+	local tmp="$(mktemp multiconfig.XXXXXXXXXX)"
+	remote_source "$src" > "$tmp"
+	local refhash="$(installed_hash "$out")"
+	if [ -n "$refhash" ]; then
+		change=false
+		if [ -f "$out" ]; then
+			local cursha="$(sha256 "$out")"
+			if [ "$cursha" != "$(sha256 "$tmp")" ]; then
+				echo "Updating file ($src): $out"
+				[ "$cursha" = "$refhash" ] || echo "File was edited manually! $out"
+				echo "$tmp	$out" >> "$MC_QUEUE_FILE"
+				change=true
+			fi
+		else
+			echo "Output is not a file! $out"
+			echo "$tmp	$out" >> "$MC_QUEUE_FILE"
+			change=true
+		fi
+	else
+		echo "New file ($src): $out"
+		echo "$tmp	$out" >> "$MC_QUEUE_FILE"
+		change=true
+	fi
+}
+
+# Apply all queued changes and cleanup
+apply() {
+	local new="$MC_STATUS_FILE.new"
+	echo -n > "$new"
+	while IFS=\t read src out; do
+		if [ -e "$out" ]; then
+			local trash="$MC_TRASH_DIR/$out.$(date +%y%m%d%H%M%S)"
+			if [ -f "$out" ]; then
+				if [ "$(installed_hash "$out")" != "$(sha256 "$out")" ]; then
+					echo "File was manually changed: $out -> $trash"
+					cp "$out" "$trash"
+				fi
+			else
+				echo "Path exists but is not a file: $out -> $trash"
+				mv "$out" "$trash"
+			fi
+		fi
+		echo "Updating: $out"
+		mv "$src" "$out"
+		sha256 "$out" >> "$new"
+	done < "$MC_QUEUE_FILE"
+	rm "$MC_QUEUE_FILE"
+	mv "$new" "$MC_STATUS_FILE"
+	change=
+}
+
+# TODO somehow add support for installing directories. Most probably by having
+# remote script returning list of files in directory and then calling inst on
+# them.
+
+# Returns string informing you of distribution type but only if given distribution
+# is supported. If ditribution is not supported then it returns "unknown".
+distribution() {
+	if [ -f /etc/gentoo-release ]; then
+		echo "gentoo"
+	elif [ -f /etc/alpine-release ]; then
+		echo "alpine"
+	elif [ -f /etc/openwrt_version ]; then
+		echo "openwrt"
+	else
+		echo "unknown"
+	fi
+}