main.c

   1 /*
   2  * Copyright (C) 2013-2014 Jo-Philipp Wich <jow@openwrt.org>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16
  17 #include <stdio.h>
  18 #include <stdbool.h>
  19 #include <unistd.h>
  20 #include <errno.h>
  21
  22 #ifdef JSONC
  23         #include <json.h>
  24 #else
  25         #include <json-c/json.h>
  26 #endif
  27
  28 #include <libubox/list.h>
  29
  30 #include "lexer.h"
  31 #include "parser.h"
  32 #include "matcher.h"
  33
  34
  35 struct match_item {
  36         struct json_object *jsobj;
  37         struct list_head list;
  38 };
  39
  40 static struct json_object *
  41 parse_json(FILE *fd, const char *source, const char **error)
  42 {
  43         int len;
  44         char buf[256];
  45         struct json_object *obj = NULL;
  46         struct json_tokener *tok = json_tokener_new();
  47         enum json_tokener_error err = json_tokener_continue;
  48
  49         if (!tok)
  50                 return NULL;
  51
  52         if (source)
  53         {
  54                 obj = json_tokener_parse_ex(tok, source, strlen(source));
  55                 err = json_tokener_get_error(tok);
  56         }
  57         else
  58         {
  59                 while ((len = fread(buf, 1, sizeof(buf), fd)) > 0)
  60                 {
  61                         obj = json_tokener_parse_ex(tok, buf, len);
  62                         err = json_tokener_get_error(tok);
  63
  64                         if (!err || err != json_tokener_continue)
  65                                 break;
  66                 }
  67         }
  68
  69         json_tokener_free(tok);
  70
  71         if (err)
  72         {
  73                 if (err == json_tokener_continue)
  74                         err = json_tokener_error_parse_eof;
  75
  76                 *error = json_tokener_error_desc(err);
  77                 return NULL;
  78         }
  79
  80         return obj;
  81 }
  82
  83 static void
  84 print_string(const char *s)
  85 {
  86         const char *p;
  87
  88         printf("'");
  89
  90         for (p = s; *p; p++)
  91         {
  92                 if (*p == '\'')
  93                         printf("'\"'\"'");
  94                 else
  95                         printf("%c", *p);
  96         }
  97
  98         printf("'");
  99 }
 100
 101 static void
 102 export_value(struct list_head *matches, const char *prefix)
 103 {
 104         int n, len;
 105         bool first = true;
 106         struct match_item *item;
 107
 108         if (list_empty(matches))
 109                 return;
 110
 111         if (prefix)
 112         {
 113                 printf("export %s=", prefix);
 114
 115                 list_for_each_entry(item, matches, list)
 116                 {
 117                         switch (json_object_get_type(item->jsobj))
 118                         {
 119                         case json_type_object:
 120                                 ; /* a label can only be part of a statement */
 121                                 json_object_object_foreach(item->jsobj, key, val)
 122                                 {
 123                                         if (!val)
 124                                                 continue;
 125
 126                                         if (!first)
 127                                                 printf("\\ ");
 128
 129                                         print_string(key);
 130                                         first = false;
 131                                 }
 132                                 break;
 133
 134                         case json_type_array:
 135                                 for (n = 0, len = json_object_array_length(item->jsobj);
 136                                      n < len; n++)
 137                                 {
 138                                         if (!first)
 139                                                 printf("\\ ");
 140
 141                                         printf("%d", n);
 142                                         first = false;
 143                                 }
 144                                 break;
 145
 146                         case json_type_boolean:
 147                                 if (!first)
 148                                         printf("\\ ");
 149                                 printf("%d", json_object_get_boolean(item->jsobj));
 150                                 break;
 151
 152                         case json_type_int:
 153                                 if (!first)
 154                                         printf("\\ ");
 155                                 printf("%d", json_object_get_int(item->jsobj));
 156                                 break;
 157
 158                         case json_type_double:
 159                                 if (!first)
 160                                         printf("\\ ");
 161                                 printf("%f", json_object_get_double(item->jsobj));
 162                                 break;
 163
 164                         case json_type_string:
 165                                 if (!first)
 166                                         printf("\\ ");
 167                                 print_string(json_object_get_string(item->jsobj));
 168                                 break;
 169
 170                         case json_type_null:
 171                                 break;
 172                         }
 173
 174                         first = false;
 175                 }
 176
 177                 printf("; ");
 178         }
 179         else
 180         {
 181                 list_for_each_entry(item, matches, list)
 182                         printf("%s\n", json_object_to_json_string(item->jsobj));
 183         }
 184 }
 185
 186 static void
 187 export_type(struct list_head *matches, const char *prefix)
 188 {
 189         bool first = true;
 190         struct match_item *item;
 191         const char *types[] = {
 192                 "null",
 193                 "boolean",
 194                 "double",
 195                 "int",
 196                 "object",
 197                 "array",
 198                 "string"
 199         };
 200
 201         if (list_empty(matches))
 202                 return;
 203
 204         if (prefix)
 205                 printf("export %s=", prefix);
 206
 207         list_for_each_entry(item, matches, list)
 208         {
 209                 if (!first)
 210                         printf("\\ ");
 211
 212                 printf("%s", types[json_object_get_type(item->jsobj)]);
 213                 first = false;
 214         }
 215
 216         if (prefix)
 217                 printf("; ");
 218         else
 219                 printf("\n");
 220 }
 221
 222 static void
 223 match_cb(struct json_object *res, void *priv)
 224 {
 225         struct list_head *h = priv;
 226         struct match_item *i = calloc(1, sizeof(*i));
 227
 228         if (i)
 229         {
 230                 i->jsobj = res;
 231                 list_add_tail(&i->list, h);
 232         }
 233 }
 234
 235 static bool
 236 filter_json(int opt, struct json_object *jsobj, char *expr)
 237 {
 238         struct jp_state *state;
 239         const char *prefix = NULL;
 240         struct list_head matches;
 241         struct match_item *item, *tmp;
 242         struct json_object *res = NULL;
 243
 244         state = jp_parse(expr);
 245
 246         if (!state || state->error)
 247         {
 248                 fprintf(stderr, "In expression '%s': %s\n",
 249                         expr, state ? state->error : "Out of memory");
 250
 251                 goto out;
 252         }
 253
 254         INIT_LIST_HEAD(&matches);
 255
 256         res = jp_match(state->path, jsobj, match_cb, &matches);
 257         prefix = (state->path->type == T_LABEL) ? state->path->str : NULL;
 258
 259         switch (opt)
 260         {
 261         case 't':
 262                 export_type(&matches, prefix);
 263                 break;
 264
 265         default:
 266                 export_value(&matches, prefix);
 267                 break;
 268         }
 269
 270         list_for_each_entry_safe(item, tmp, &matches, list)
 271                 free(item);
 272
 273 out:
 274         if (state)
 275                 jp_free(state);
 276
 277         return !!res;
 278 }
 279
 280 int main(int argc, char **argv)
 281 {
 282         int opt, rv = 0;
 283         FILE *input = stdin;
 284         struct json_object *jsobj = NULL;
 285         const char *jserr = NULL, *source = NULL;
 286
 287         while ((opt = getopt(argc, argv, "i:s:e:t:q")) != -1)
 288         {
 289                 switch (opt)
 290                 {
 291                 case 'i':
 292                         input = fopen(optarg, "r");
 293
 294                         if (!input)
 295                         {
 296                                 fprintf(stderr, "Failed to open %s: %s\n",
 297                                                 optarg, strerror(errno));
 298
 299                                 rv = 125;
 300                                 goto out;
 301                         }
 302
 303                         break;
 304
 305                 case 's':
 306                         source = optarg;
 307                         break;
 308
 309                 case 't':
 310                 case 'e':
 311                         if (!jsobj)
 312                         {
 313                                 jsobj = parse_json(input, source, &jserr);
 314
 315                                 if (!jsobj)
 316                                 {
 317                                         fprintf(stderr, "Failed to parse json data: %s\n",
 318                                                 jserr);
 319
 320                                         rv = 126;
 321                                         goto out;
 322                                 }
 323                         }
 324
 325                         if (!filter_json(opt, jsobj, optarg))
 326                                 rv = 1;
 327
 328                         break;
 329
 330                 case 'q':
 331                         fclose(stderr);
 332                         break;
 333                 }
 334         }
 335
 336 out:
 337         if (jsobj)
 338                 json_object_put(jsobj);
 339
 340         if (input != stdin)
 341                 fclose(input);
 342
 343         return rv;
 344 }