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         bool indent;
 102         int indent_level;
 103 };
 104
 105 static bool blobmsg_puts(struct strbuf *s, const char *c, int len)
 106 {
 107         if (len <= 0)
 108                 return true;
 109
 110         if (s->pos + len >= s->len) {
 111                 s->len += 16;
 112                 s->buf = realloc(s->buf, s->len);
 113                 if (!s->buf)
 114                         return false;
 115         }
 116         memcpy(s->buf + s->pos, c, len);
 117         s->pos += len;
 118         return true;
 119 }
 120
 121 static void add_separator(struct strbuf *s)
 122 {
 123         static char indent_chars[17] = "\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t";
 124         static const char indent_space = ' ';
 125         int indent;
 126         char *start;
 127
 128         if (!s->indent) {
 129                 blobmsg_puts(s, &indent_space, 1);
 130                 return;
 131         }
 132
 133         indent = s->indent_level;
 134         if (indent > 16)
 135                 indent = 16;
 136
 137         start = &indent_chars[sizeof(indent_chars) - indent - 1];
 138         *start = '\n';
 139         blobmsg_puts(s, start, indent + 1);
 140         *start = '\t';
 141 }
 142
 143
 144 static void blobmsg_format_string(struct strbuf *s, const char *str)
 145 {
 146         const char *p, *last = str, *end = str + strlen(str);
 147         char buf[8] = "\\u00";
 148
 149         blobmsg_puts(s, "\"", 1);
 150         for (p = str; *p; p++) {
 151                 char escape = '\0';
 152                 int len;
 153
 154                 switch(*p) {
 155                 case '\b':
 156                         escape = 'b';
 157                         break;
 158                 case '\n':
 159                         escape = 'n';
 160                         break;
 161                 case '\t':
 162                         escape = 't';
 163                         break;
 164                 case '\r':
 165                         escape = 'r';
 166                         break;
 167                 case '"':
 168                 case '\\':
 169                 case '/':
 170                         escape = *p;
 171                         break;
 172                 default:
 173                         if (*p < ' ')
 174                                 escape = 'u';
 175                         break;
 176                 }
 177
 178                 if (!escape)
 179                         continue;
 180
 181                 if (p > last)
 182                         blobmsg_puts(s, last, p - last);
 183                 last = p + 1;
 184                 buf[1] = escape;
 185
 186                 if (escape == 'u') {
 187                         sprintf(buf + 4, "%02x", (unsigned char) *p);
 188                         len = 4;
 189                 } else {
 190                         len = 2;
 191                 }
 192                 blobmsg_puts(s, buf, len);
 193         }
 194
 195         blobmsg_puts(s, last, end - last);
 196         blobmsg_puts(s, "\"", 1);
 197 }
 198
 199 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array);
 200
 201 static void blobmsg_format_element(struct strbuf *s, struct blob_attr *attr, bool array, bool head)
 202 {
 203         const char *data_str;
 204         char buf[32];
 205         void *data;
 206         int len;
 207
 208         if (!blobmsg_check_attr(attr, false))
 209                 return;
 210
 211         if (!array && blobmsg_name(attr)[0]) {
 212                 blobmsg_format_string(s, blobmsg_name(attr));
 213                 blobmsg_puts(s, ": ", 2);
 214         }
 215         if (head) {
 216                 data = blob_data(attr);
 217                 len = blob_len(attr);
 218         } else {
 219                 data = blobmsg_data(attr);
 220                 len = blobmsg_data_len(attr);
 221
 222                 if (s->custom_format) {
 223                         data_str = s->custom_format(s->priv, attr);
 224                         if (data_str)
 225                                 goto out;
 226                 }
 227         }
 228
 229         data_str = buf;
 230         switch(blob_id(attr)) {
 231         case BLOBMSG_TYPE_BOOL:
 232                 sprintf(buf, "%s", *(uint8_t *)data ? "true" : "false");
 233                 break;
 234         case BLOBMSG_TYPE_INT32:
 235                 sprintf(buf, "%d", *(uint32_t *)data);
 236                 break;
 237         case BLOBMSG_TYPE_INT64:
 238                 sprintf(buf, "%lld", (long long int) *(uint64_t *)data);
 239                 break;
 240         case BLOBMSG_TYPE_STRING:
 241                 blobmsg_format_string(s, data);
 242                 return;
 243         case BLOBMSG_TYPE_ARRAY:
 244                 blobmsg_format_json_list(s, data, len, true);
 245                 return;
 246         case BLOBMSG_TYPE_TABLE:
 247                 blobmsg_format_json_list(s, data, len, false);
 248                 return;
 249         }
 250
 251 out:
 252         blobmsg_puts(s, data_str, strlen(data_str));
 253 }
 254
 255 static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array)
 256 {
 257         struct blob_attr *pos;
 258         bool first = true;
 259         int rem = len;
 260
 261         blobmsg_puts(s, (array ? "[" : "{" ), 1);
 262         s->indent_level++;
 263         add_separator(s);
 264         __blob_for_each_attr(pos, attr, rem) {
 265                 if (!first) {
 266                         blobmsg_puts(s, ",", 1);
 267                         add_separator(s);
 268                 }
 269
 270                 blobmsg_format_element(s, pos, array, false);
 271                 first = false;
 272         }
 273         s->indent_level--;
 274         add_separator(s);
 275         blobmsg_puts(s, (array ? "]" : "}"), 1);
 276 }
 277
 278 char *blobmsg_format_json_with_cb(struct blob_attr *attr, bool list, blobmsg_json_format_t cb, void *priv, int indent)
 279 {
 280         struct strbuf s;
 281
 282         s.len = blob_len(attr);
 283         s.buf = malloc(s.len);
 284         s.pos = 0;
 285         s.custom_format = cb;
 286         s.priv = priv;
 287         s.indent = false;
 288
 289         if (indent >= 0) {
 290                 s.indent = true;
 291                 s.indent_level = indent;
 292         }
 293
 294         if (list)
 295                 blobmsg_format_json_list(&s, blob_data(attr), blob_len(attr), false);
 296         else
 297                 blobmsg_format_element(&s, attr, false, false);
 298
 299         if (!s.len)
 300                 return NULL;
 301
 302         s.buf = realloc(s.buf, s.pos + 1);
 303         s.buf[s.pos] = 0;
 304
 305         return s.buf;
 306 }