add jshn (JSON SHell Notation), a small utility and shell library for parsing and generating json data

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@25547 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 109 insertions, 0 deletions

diff --git a/package/jshn/files/jshn.sh b/package/jshn/files/jshn.sh
new file mode 100644
index 000000000..2dddfe8bf
--- /dev/null
+++ b/package/jshn/files/jshn.sh
@@ -0,0 +1,109 @@
+[ -z "$N" ] && . /etc/functions.sh
+
+# functions for parsing and generating json
+
+json_init() {
+	[ -n "$JSON_UNSET" ] && eval "unset $JSON_UNSET"
+	export -- JSON_SEQ=0 JSON_STACK= JSON_CUR="JSON_VAR" JSON_UNSET=
+}
+
+json_add_generic() {
+	local type="$1"
+	local var="$2"
+	local val="$3"
+	local cur="${4:-$JSON_CUR}"
+
+	export ${NO_EXPORT:+-n} -- "${cur}_$var=$val"
+	export ${NO_EXPORT:+-n} -- "TYPE_${cur}_$var=$type"
+	append JSON_UNSET "${cur}_$var TYPE_${cur}_$var"
+	append "KEYS_${cur}" "$var"
+}
+
+json_add_table() {
+	JSON_SEQ=$(($JSON_SEQ + 1))
+	append JSON_STACK "$JSON_CUR"
+	local table="JSON_TABLE$JSON_SEQ"
+	export ${NO_EXPORT:+-n} -- "UP_$table=$JSON_CUR"
+	JSON_CUR="$table"
+}
+
+json_add_object() {
+	local cur="$JSON_CUR"
+	json_add_table
+	json_add_generic object "$1" "$JSON_CUR" "$cur"
+}
+
+json_close_object() {
+	local oldstack="$JSON_STACK"
+	export "KEYS_${JSON_CUR}"
+	JSON_CUR="${JSON_STACK##* }"
+	JSON_STACK="${JSON_STACK% *}"
+	[[ "$oldstack" == "$JSON_STACK" ]] && JSON_STACK=
+}
+
+json_add_array() {
+	local cur="$JSON_CUR"
+	json_add_table
+	json_add_generic array "$1" "$JSON_CUR" "$cur"
+}
+
+json_close_array() {
+	json_close_object
+}
+
+json_add_string() {
+	json_add_generic string "$1" "$2"
+}
+
+json_add_int() {
+	json_add_generic int "$1" "$2"
+}
+
+json_add_boolean() {
+	json_add_generic boolean "$1" "$2"
+}
+
+# functions read access to json variables
+
+json_load() {
+	eval `jshn -r "$1"`
+}
+
+json_dump() {
+	jshn -w
+}
+
+json_get_type() {
+	local dest="$1"
+	local var="$2"
+	eval "export ${NO_EXPORT:+-n} -- \"$dest=\${TYPE_${JSON_CUR}_$var}\""
+}
+
+json_get_var() {
+	local dest="$1"
+	local var="$2"
+	eval "export ${NO_EXPORT:+-n} -- \"$dest=\${${JSON_CUR}_$var}\""
+}
+
+json_select() {
+	local target="$1"
+	local type
+
+	[ -z "$1" ] && {
+		JSON_CUR="JSON_VAR"
+		return
+	}
+	[[ "$1" == ".." ]] && {
+		eval "JSON_CUR=\"\${UP_$JSON_CUR}\""
+		return;
+	}
+	json_get_type type "$target"
+	case "$type" in
+		object|array)
+			json_get_var JSON_CUR "$target"
+		;;
+		*)
+			echo "WARNING: Variable '$target' does not exist or is not an array/object"
+		;;
+	esac
+}