--- /dev/null
+/*
+ * Copyright (C) 2016, 2017 "IoT.bzh"
+ * Author José Bollo <jose.bollo@iot.bzh>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/*
+ * This simple program expands the object { "$ref": "#/path/to/a/target" }
+ *
+ * For example:
+ *
+ * {
+ * "type":{
+ * "a": "int",
+ * "b": { "$ref": "#/type/a" }
+ * }
+ * }
+ *
+ * will be exapanded to
+ *
+ * {
+ * "type":{
+ * "a": "int",
+ * "b": "int"
+ * }
+ * }
+ *
+ * Invocation: program [file|-]...
+ *
+ * without arguments, it reads the input.
+ */
+
+#define _GNU_SOURCE
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <json-c/json.h>
+
+/**
+ * records path to the expanded node
+ */
+struct path
+{
+ struct json_object *object; /**< node being expanded */
+ struct path *upper; /**< link to upper expanded nodes */
+};
+
+/**
+ * root of the JSON being parsed
+ */
+struct json_object *root;
+
+/**
+ * Search for a reference of type "#/a/b/c" int the
+ * parsed JSON object
+ */
+struct json_object *search(const char *path)
+{
+ char *d;
+ struct json_object *i;
+
+ /* does it match #/ at the beginning? */
+ if (path[0] != '#' || (path[0] && path[1] != '/'))
+ return NULL;
+
+ /* search from root to target */
+ i = root;
+ d = strdupa(path+2);
+ d = strtok(d, "/");
+ while(i && d) {
+ if (!json_object_object_get_ex(i, d, &i))
+ return NULL;
+ d = strtok(NULL, "/");
+ }
+ return i;
+}
+
+/**
+ * Expands the node designated by path and returns its expanded form
+ */
+struct json_object *expand(struct path path)
+{
+ struct path *p;
+ struct json_object *o, *x;
+ int n, i;
+ struct json_object_iterator ji, jn;
+
+ /* expansion depends of the type of the node */
+ switch (json_object_get_type(path.object)) {
+ case json_type_object:
+ /* for object, look if it contains a property "$ref" */
+ if (json_object_object_get_ex(path.object, "$ref", &o)) {
+ /* yes, reference, try to substitute its target */
+ if (!json_object_is_type(o, json_type_string)) {
+ fprintf(stderr, "found a $ref not being string. Is: %s\n", json_object_get_string(o));
+ exit(1);
+ }
+ x = search(json_object_get_string(o));
+ if (!x) {
+ fprintf(stderr, "$ref not found. Was: %s\n", json_object_get_string(o));
+ exit(1);
+ }
+ p = &path;
+ while(p) {
+ if (x == p->object) {
+ fprintf(stderr, "$ref recursive. Was: %s\n", json_object_get_string(o));
+ exit(1);
+ }
+ p = p->upper;
+ }
+ /* cool found, return a new instance of the target */
+ return json_object_get(x);
+ }
+ /* no, expand the values */
+ ji = json_object_iter_begin(path.object);
+ jn = json_object_iter_end(path.object);
+ while (!json_object_iter_equal(&ji, &jn)) {
+ o = json_object_iter_peek_value(&ji);
+ x = expand((struct path){ .object = o, .upper = &path });
+ if (x != o)
+ json_object_object_add(path.object, json_object_iter_peek_name(&ji), x);
+ json_object_iter_next(&ji);
+ }
+ break;
+ case json_type_array:
+ /* expand the values of arrays */
+ i = 0;
+ n = json_object_array_length(path.object);
+ while (i != n) {
+ o = json_object_array_get_idx(path.object, i);
+ x = expand((struct path){ .object = o, .upper = &path });
+ if (x != o)
+ json_object_array_put_idx(path.object, i, x);
+ i++;
+ }
+ break;
+ default:
+ /* otherwise no expansion */
+ break;
+ }
+ /* return the given node */
+ return path.object;
+}
+
+/**
+ * process a file and prints its expansion on stdout
+ */
+void process(char *filename)
+{
+ /* translate - */
+ if (!strcmp(filename, "-"))
+ filename = "/dev/stdin";
+
+ /* check access */
+ if (access(filename, R_OK)) {
+ fprintf(stderr, "can't access file %s\n", filename);
+ exit(1);
+ }
+
+ /* read the file */
+ root = json_object_from_file(filename);
+ if (!root) {
+ fprintf(stderr, "reading file %s produced null\n", filename);
+ exit(1);
+ }
+
+ /* expand */
+ root = expand((struct path){ .object = root, .upper = NULL });
+
+ /* print the result */
+ json_object_to_file_ext ("/dev/stdout", root, JSON_C_TO_STRING_PRETTY);
+
+ /* clean up */
+ json_object_put(root);
+}
+
+/** process the list of files or stdin if none */
+int main(int ac, char **av)
+{
+ if (!*++av)
+ process("-");
+ else {
+ do { process(*av); } while(*++av);
+ }
+ return 0;
+}
+
Code Review / src / app-framework-binder.git / blobdiff