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

SVN-Revision: 25547

package/jshn/Makefile

@@ -0,0 +1,32 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=jshn
+PKG_VERSION:=0.1
+PKG_RELEASE=1
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/jshn
+  SECTION:=utils
+  CATEGORY:=Utilities
+  DEPENDS:=+libjson
+  TITLE:=JSON SHell Notation
+endef
+
+define Package/jshn/description
+  Library for parsing and generating JSON from shell scripts
+endef
+
+TARGET_CFLAGS += -I$(STAGING_DIR)/usr/include --std=gnu99
+
+define Build/Compile
+	$(TARGET_CC) $(TARGET_CFLAGS) -o $(PKG_BUILD_DIR)/jshn src/jshn.c $(TARGET_LDFLAGS) -ljson
+endef
+
+define Package/jshn/install
+	$(INSTALL_DIR) $(1)/bin $(1)/lib/functions
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/jshn $(1)/bin
+	$(INSTALL_DATA) ./files/jshn.sh $(1)/lib/functions
+endef
+
+$(eval $(call BuildPackage,jshn))

package/jshn/example.txt

@@ -0,0 +1,19 @@
+. /lib/functions/jshn.sh
+
+# generating json data
+json_init
+json_add_string "msg" "Hello, world!"
+json_add_object "test"
+json_add_int "testdata" "1"
+json_close_object
+MSG=`json_dump`
+# MSG now contains: { "msg": "Hello, world!", "test": { "testdata": 1 } }
+
+
+# parsing json data
+json_load "$MSG"
+json_select test
+json_get_var var1 testdata
+json_select ..
+json_get_var var2 msg
+echo "msg: $var2 - testdata: $var1"

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
+}

package/jshn/src/jshn.c

@@ -0,0 +1,245 @@
+#include <json/json.h>
+#include <libubox/list.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <ctype.h>
+#include <getopt.h>
+
+#define MAX_VARLEN	256
+
+static int add_json_element(const char *key, json_object *obj);
+
+static int add_json_object(json_object *obj)
+{
+	int ret = 0;
+
+	json_object_object_foreach(obj, key, val) {
+		ret = add_json_element(key, val);
+		if (ret)
+			break;
+	}
+	return ret;
+}
+
+static int add_json_array(struct array_list *a)
+{
+	char seq[12];
+	int i, len;
+	int ret;
+
+	for (i = 0, len = array_list_length(a); i < len; i++) {
+		sprintf(seq, "%d", i);
+		ret = add_json_element(seq, array_list_get_idx(a, i));
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void add_json_string(const char *str)
+{
+	char *ptr = (char *) str;
+	int len;
+	char *c;
+
+	while ((c = strchr(ptr, '\'')) != NULL) {
+		len = c - ptr;
+		if (len > 0)
+			fwrite(ptr, len, 1, stdout);
+		ptr = c + 1;
+		c = "'\\''";
+		fwrite(c, strlen(c), 1, stdout);
+	}
+	len = strlen(ptr);
+	if (len > 0)
+		fwrite(ptr, len, 1, stdout);
+}
+
+static void write_key_string(const char *key)
+{
+	while (*key) {
+		putc(isalnum(*key) ? *key : '_', stdout);
+		key++;
+	}
+}
+
+static int add_json_element(const char *key, json_object *obj)
+{
+	char *type;
+
+	if (!obj)
+		return -1;
+
+	switch (json_object_get_type(obj)) {
+	case json_type_object:
+		type = "object";
+		break;
+	case json_type_array:
+		type = "array";
+		break;
+	case json_type_string:
+		type = "string";
+		break;
+	case json_type_boolean:
+		type = "boolean";
+		break;
+	case json_type_int:
+		type = "int";
+		break;
+	default:
+		return -1;
+	}
+
+	fprintf(stdout, "json_add_%s '", type);
+	write_key_string(key);
+
+	switch (json_object_get_type(obj)) {
+	case json_type_object:
+		fprintf(stdout, "';\n");
+		add_json_object(obj);
+		fprintf(stdout, "json_close_object;\n");
+		break;
+	case json_type_array:
+		fprintf(stdout, "';\n");
+		add_json_array(json_object_get_array(obj));
+		fprintf(stdout, "json_close_array;\n");
+		break;
+	case json_type_string:
+		fprintf(stdout, "' '");
+		add_json_string(json_object_get_string(obj));
+		fprintf(stdout, "';\n");
+		break;
+	case json_type_boolean:
+		fprintf(stdout, "' %d;\n", json_object_get_boolean(obj));
+		break;
+	case json_type_int:
+		fprintf(stdout, "' %d;\n", json_object_get_int(obj));
+		break;
+	default:
+		return -1;
+	}
+
+	return 0;
+}
+
+static int jshn_parse(const char *str)
+{
+	json_object *obj;
+
+	obj = json_tokener_parse(str);
+	if (is_error(obj) || json_object_get_type(obj) != json_type_object) {
+		fprintf(stderr, "Failed to parse message data\n");
+		return 1;
+	}
+	fprintf(stdout, "json_init;\n");
+	add_json_object(obj);
+	fflush(stdout);
+
+	return 0;
+}
+
+static char *get_keys(const char *prefix)
+{
+	char *keys;
+
+	keys = alloca(strlen(prefix) + sizeof("KEYS_") + 1);
+	sprintf(keys, "KEYS_%s", prefix);
+	return getenv(keys);
+}
+
+static void get_var(const char *prefix, const char *name, char **var, char **type)
+{
+	char *tmpname;
+
+	tmpname = alloca(strlen(prefix) + 1 + strlen(name) + 1 + sizeof("TYPE_"));
+	sprintf(tmpname, "TYPE_%s_%s", prefix, name);
+	*var = getenv(tmpname + 5);
+	*type = getenv(tmpname);
+}
+
+static json_object *jshn_add_objects(json_object *obj, const char *prefix, bool array);
+
+static void jshn_add_object_var(json_object *obj, bool array, const char *prefix, const char *name)
+{
+	json_object *new;
+	char *var, *type;
+
+	get_var(prefix, name, &var, &type);
+	if (!var || !type)
+		return;
+
+	if (!strcmp(type, "array")) {
+		new = json_object_new_array();
+		jshn_add_objects(new, var, true);
+	} else if (!strcmp(type, "object")) {
+		new = json_object_new_object();
+		jshn_add_objects(new, var, false);
+	} else if (!strcmp(type, "string")) {
+		new = json_object_new_string(var);
+	} else if (!strcmp(type, "int")) {
+		new = json_object_new_int(atoi(var));
+	} else if (!strcmp(type, "boolean")) {
+		new = json_object_new_boolean(!!atoi(var));
+	} else {
+		return;
+	}
+
+	if (array)
+		json_object_array_add(obj, new);
+	else
+		json_object_object_add(obj, name, new);
+}
+
+static json_object *jshn_add_objects(json_object *obj, const char *prefix, bool array)
+{
+	char *keys, *key, *brk;
+
+	keys = get_keys(prefix);
+	if (!keys || !obj)
+		goto out;
+
+	for (key = strtok_r(keys, " ", &brk); key;
+	     key = strtok_r(NULL, " ", &brk)) {
+		jshn_add_object_var(obj, array, prefix, key);
+	}
+
+out:
+	return obj;
+}
+
+static int jshn_format(void)
+{
+	json_object *obj;
+
+	obj = json_object_new_object();
+	jshn_add_objects(obj, "JSON_VAR", false);
+	fprintf(stdout, "%s\n", json_object_to_json_string(obj));
+	json_object_put(obj);
+	return 0;
+}
+
+static int usage(const char *progname)
+{
+	fprintf(stderr, "Usage: %s -r <message>|-w\n", progname);
+	return 2;
+}
+
+int main(int argc, char **argv)
+{
+	int ch;
+
+	while ((ch = getopt(argc, argv, "r:w")) != -1) {
+		switch(ch) {
+		case 'r':
+			return jshn_parse(optarg);
+		case 'w':
+			return jshn_format();
+		default:
+			return usage(argv[0]);
+		}
+	}
+	return usage(argv[0]);
+}