blobmsg_json.c

   1 /*
   2  * blobmsg - library for generating/parsing structured blob messages
   3  *
   4  * Copyright (C) 2010 Felix Fietkau <nbd@openwrt.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU Lesser General Public License version 2.1
   8  * as published by the Free Software Foundation
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include "blobmsg.h"
  17 #include "blobmsg_json.h"
  18
  19 static bool blobmsg_add_object(struct blob_buf *b, json_object *obj)
  20 {
  21         json_object_object_foreach(obj, key, val) {
  22                 if (!blobmsg_add_json_element(b, key, val))
  23                         return false;
  24         }
  25         return true;
  26 }
  27
  28 static bool blobmsg_add_array(struct blob_buf *b, struct array_list *a)
  29 {
  30         int i, len;
  31
  32         for (i = 0, len = array_list_length(a); i < len; i++) {
  33                 if (!blobmsg_add_json_element(b, NULL, array_list_get_idx(a, i)))
  34                         return false;
  35         }
  36
  37         return true;
  38 }
  39
  40 bool blobmsg_add_json_element(struct blob_buf *b, const char *name, json_object *obj)
  41 {
  42         bool ret = true;
  43         void *c;
  44
  45         if (!obj)
  46                 return false;
  47
  48         switch (json_object_get_type(obj)) {
  49         case json_type_object:
  50                 c = blobmsg_open_table(b, name);
  51                 ret = blobmsg_add_object(b, obj);
  52                 blobmsg_close_table(b, c);
  53                 break;
  54         case json_type_array:
  55                 c = blobmsg_open_array(b, name);
  56                 ret = blobmsg_add_array(b, json_object_get_array(obj));
  57                 blobmsg_close_array(b, c);
  58                 break;
  59         case json_type_string:
  60                 blobmsg_add_string(b, name, json_object_get_string(obj));
  61                 break;
  62         case json_type_boolean:
  63                 blobmsg_add_u8(b, name, json_object_get_boolean(obj));
  64                 break;
  65         case json_type_int:
  66                 blobmsg_add_u32(b, name, json_object_get_int(obj));
  67                 break;
  68         default:
  69                 return false;
  70         }
  71         return ret;
  72 }
  73
  74 bool blobmsg_add_json_from_string(struct blob_buf *b, const char *str)
  75 {
  76         json_object *obj;
  77         bool ret = false;
  78
  79         obj = json_tokener_parse(str);
  80         if (is_error(obj))
  81                 return false;
  82
  83         if (json_object_get_type(obj) != json_type_object)
  84                 goto out;
  85
  86         ret = blobmsg_add_object(b, obj);
  87
  88 out:
  89         json_object_put(obj);
  90         return ret;
  91 }
  92
  93
  94 struct strbuf {
  95         int len;
  96         int pos;
  97         char *buf;
  98
  99         blobmsg_json_format_t custom_format;
 100         void *priv;
 101 };
 102
 103 static bool blobmsg_puts(struct strbuf *s, const char *c, int len)
 104 {
 105         if (len <= 0)
 106                 return true;
 107
 108         if (s->pos + len >= s->len) {
 109                 s->len += 16;
 110                 s->buf = realloc(s->buf, s->len);
 111                 if (!s->buf)
 112                         return false;
 113         }
 114         memcpy(s->buf + s->pos, c, len);
 115         s->pos += len;
 116         return true;
 117 }
 118
 119 static void blobmsg_format_string(struct strbuf *s, const char *str)
 120 {
 121         const char *p, *last = str, *end = str + strlen(str);
 122         char buf[8] = "\\u00";
 123
 124         blobmsg_puts(s, "\"", 1);
 125         for (p = str; *p; p++) {
 126                 char escape = '\0';
 127                 int len;
 128
 129                 switch(*p) {
 130                 case '\b':
 131                         escape = 'b';
 132                         break;
 133                 case '\n':
 134                         escape = 'n';
 135                         break;
 136                 case '\t':
 137                         escape = 't';
 138                         break;
 139                 case '\r':
 140                         escape = 'r';
 141                         break;
 142                 case '"':
 143                 case '\\':
 144                 case '/':
 145                         escape = *p;
 146                         break;
 147                 default:
 148                         if (*p < ' ')
 149                                 escape = 'u';
 150                         break;
 151                 }
 152
 153                 if (!escape)
 154                         continue;
 155
 156                 if (p > last)
 157                         blobmsg_puts(s, last, p - last);
 158                 last = p + 1;
 159                 buf[1] = escape;
 160
 161                 if (escape == 'u') {
 162                         sprintf(buf + 4, "%02x", (unsigned char) *p);
 163                         len = 4;
 164                 } else {
 165                         len = 2;
 166                 }
 167                 blobmsg_puts(s, buf, len);
 168         }
 169
 170         blobmsg_puts(s, last, end - last);
 171         blobmsg_puts(s, "\"", 1);
 172 }
 173
 174 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array);
 175
 176 static void blobmsg_format_element(struct strbuf *s, struct blob_attr *attr, bool array, bool head)
 177 {
 178         const char *data_str;
 179         char buf[32];
 180         void *data;
 181         int len;
 182
 183         if (!array && blobmsg_name(attr)[0]) {
 184                 blobmsg_format_string(s, blobmsg_name(attr));
 185                 blobmsg_puts(s, ":", 1);
 186         }
 187         if (head) {
 188                 data = blob_data(attr);
 189                 len = blob_len(attr);
 190         } else {
 191                 data = blobmsg_data(attr);
 192                 len = blobmsg_data_len(attr);
 193
 194                 if (s->custom_format) {
 195                         data_str = s->custom_format(s->priv, attr);
 196                         if (data_str)
 197                                 goto out;
 198                 }
 199         }
 200
 201         data_str = buf;
 202         switch(blob_id(attr)) {
 203         case BLOBMSG_TYPE_INT8:
 204                 sprintf(buf, "%d", *(uint8_t *)data);
 205                 break;
 206         case BLOBMSG_TYPE_INT16:
 207                 sprintf(buf, "%d", *(uint16_t *)data);
 208                 break;
 209         case BLOBMSG_TYPE_INT32:
 210                 sprintf(buf, "%d", *(uint32_t *)data);
 211                 break;
 212         case BLOBMSG_TYPE_INT64:
 213                 sprintf(buf, "%lld", *(uint64_t *)data);
 214                 break;
 215         case BLOBMSG_TYPE_STRING:
 216                 blobmsg_format_string(s, data);
 217                 return;
 218         case BLOBMSG_TYPE_ARRAY:
 219                 blobmsg_format_json_list(s, data, len, true);
 220                 return;
 221         case BLOBMSG_TYPE_TABLE:
 222                 blobmsg_format_json_list(s, data, len, false);
 223                 return;
 224         }
 225
 226 out:
 227         blobmsg_puts(s, data_str, strlen(data_str));
 228 }
 229
 230 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array)
 231 {
 232         struct blob_attr *pos;
 233         bool first = true;
 234         int rem = len;
 235
 236         blobmsg_puts(s, (array ? "[ " : "{ "), 2);
 237         __blob_for_each_attr(pos, attr, rem) {
 238                 if (!first)
 239                         blobmsg_puts(s, ", ", 2);
 240
 241                 blobmsg_format_element(s, pos, array, false);
 242                 first = false;
 243         }
 244         blobmsg_puts(s, (array ? " ]" : " }"), 2);
 245 }
 246
 247 char *blobmsg_format_json_with_cb(struct blob_attr *attr, bool list, blobmsg_json_format_t cb, void *priv)
 248 {
 249         struct strbuf s;
 250
 251         s.len = blob_len(attr);
 252         s.buf = malloc(s.len);
 253         s.pos = 0;
 254         s.custom_format = cb;
 255         s.priv = priv;
 256
 257         if (list)
 258                 blobmsg_format_json_list(&s, blob_data(attr), blob_len(attr), false);
 259         else
 260                 blobmsg_format_element(&s, attr, false, false);
 261
 262         if (!s.len)
 263                 return NULL;
 264
 265         s.buf = realloc(s.buf, s.pos + 1);
 266         return s.buf;
 267 }