qobject/qjson.c

   1 /*
   2  * QObject JSON integration
   3  *
   4  * Copyright IBM, Corp. 2009
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
  10  * See the COPYING.LIB file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu/osdep.h"
  15 #include "qapi/error.h"
  16 #include "qapi/qmp/json-parser.h"
  17 #include "qapi/qmp/qjson.h"
  18 #include "qapi/qmp/qbool.h"
  19 #include "qapi/qmp/qdict.h"
  20 #include "qapi/qmp/qlist.h"
  21 #include "qapi/qmp/qnum.h"
  22 #include "qapi/qmp/qstring.h"
  23 #include "qemu/unicode.h"
  24
  25 typedef struct JSONParsingState
  26 {
  27     JSONMessageParser parser;
  28     QObject *result;
  29     Error *err;
  30 } JSONParsingState;
  31
  32 static void consume_json(void *opaque, QObject *json, Error *err)
  33 {
  34     JSONParsingState *s = opaque;
  35
  36     assert(!json != !err);
  37     assert(!s->result || !s->err);
  38
  39     if (s->result) {
  40         qobject_unref(s->result);
  41         s->result = NULL;
  42         error_setg(&s->err, "Expecting at most one JSON value");
  43     }
  44     if (s->err) {
  45         qobject_unref(json);
  46         error_free(err);
  47         return;
  48     }
  49     s->result = json;
  50     s->err = err;
  51 }
  52
  53 /*
  54  * Parse @string as JSON value.
  55  * If @ap is non-null, interpolate %-escapes.
  56  * Takes ownership of %p arguments.
  57  * On success, return the JSON value.
  58  * On failure, store an error through @errp and return NULL.
  59  * Ownership of %p arguments becomes indeterminate then.  To avoid
  60  * leaks, callers passing %p must terminate on error, e.g. by passing
  61  * &error_abort.
  62  */
  63 static QObject *qobject_from_jsonv(const char *string, va_list *ap,
  64                                    Error **errp)
  65 {
  66     JSONParsingState state = {};
  67
  68     json_message_parser_init(&state.parser, consume_json, &state, ap);
  69     json_message_parser_feed(&state.parser, string, strlen(string));
  70     json_message_parser_flush(&state.parser);
  71     json_message_parser_destroy(&state.parser);
  72
  73     if (!state.result && !state.err) {
  74         error_setg(&state.err, "Expecting a JSON value");
  75     }
  76
  77     error_propagate(errp, state.err);
  78     return state.result;
  79 }
  80
  81 QObject *qobject_from_json(const char *string, Error **errp)
  82 {
  83     return qobject_from_jsonv(string, NULL, errp);
  84 }
  85
  86 /*
  87  * Parse @string as JSON value with %-escapes interpolated.
  88  * Abort on error.  Do not use with untrusted @string.
  89  * Return the resulting QObject.  It is never null.
  90  */
  91 QObject *qobject_from_vjsonf_nofail(const char *string, va_list ap)
  92 {
  93     va_list ap_copy;
  94     QObject *obj;
  95
  96     /* va_copy() is needed when va_list is an array type */
  97     va_copy(ap_copy, ap);
  98     obj = qobject_from_jsonv(string, &ap_copy, &error_abort);
  99     va_end(ap_copy);
 100
 101     assert(obj);
 102     return obj;
 103 }
 104
 105 /*
 106  * Parse @string as JSON value with %-escapes interpolated.
 107  * Abort on error.  Do not use with untrusted @string.
 108  * Return the resulting QObject.  It is never null.
 109  */
 110 QObject *qobject_from_jsonf_nofail(const char *string, ...)
 111 {
 112     QObject *obj;
 113     va_list ap;
 114
 115     va_start(ap, string);
 116     obj = qobject_from_vjsonf_nofail(string, ap);
 117     va_end(ap);
 118
 119     return obj;
 120 }
 121
 122 /*
 123  * Parse @string as JSON object with %-escapes interpolated.
 124  * Abort on error.  Do not use with untrusted @string.
 125  * Return the resulting QDict.  It is never null.
 126  */
 127 QDict *qdict_from_vjsonf_nofail(const char *string, va_list ap)
 128 {
 129     QDict *qdict;
 130
 131     qdict = qobject_to(QDict, qobject_from_vjsonf_nofail(string, ap));
 132     assert(qdict);
 133     return qdict;
 134 }
 135
 136 /*
 137  * Parse @string as JSON object with %-escapes interpolated.
 138  * Abort on error.  Do not use with untrusted @string.
 139  * Return the resulting QDict.  It is never null.
 140  */
 141 QDict *qdict_from_jsonf_nofail(const char *string, ...)
 142 {
 143     QDict *qdict;
 144     va_list ap;
 145
 146     va_start(ap, string);
 147     qdict = qdict_from_vjsonf_nofail(string, ap);
 148     va_end(ap);
 149     return qdict;
 150 }
 151
 152 typedef struct ToJsonIterState
 153 {
 154     int indent;
 155     int pretty;
 156     int count;
 157     QString *str;
 158 } ToJsonIterState;
 159
 160 static void to_json(const QObject *obj, QString *str, int pretty, int indent);
 161
 162 static void to_json_dict_iter(const char *key, QObject *obj, void *opaque)
 163 {
 164     ToJsonIterState *s = opaque;
 165     QString *qkey;
 166     int j;
 167
 168     if (s->count) {
 169         qstring_append(s->str, s->pretty ? "," : ", ");
 170     }
 171
 172     if (s->pretty) {
 173         qstring_append(s->str, "\n");
 174         for (j = 0 ; j < s->indent ; j++)
 175             qstring_append(s->str, "    ");
 176     }
 177
 178     qkey = qstring_from_str(key);
 179     to_json(QOBJECT(qkey), s->str, s->pretty, s->indent);
 180     qobject_unref(qkey);
 181
 182     qstring_append(s->str, ": ");
 183     to_json(obj, s->str, s->pretty, s->indent);
 184     s->count++;
 185 }
 186
 187 static void to_json_list_iter(QObject *obj, void *opaque)
 188 {
 189     ToJsonIterState *s = opaque;
 190     int j;
 191
 192     if (s->count) {
 193         qstring_append(s->str, s->pretty ? "," : ", ");
 194     }
 195
 196     if (s->pretty) {
 197         qstring_append(s->str, "\n");
 198         for (j = 0 ; j < s->indent ; j++)
 199             qstring_append(s->str, "    ");
 200     }
 201
 202     to_json(obj, s->str, s->pretty, s->indent);
 203     s->count++;
 204 }
 205
 206 static void to_json(const QObject *obj, QString *str, int pretty, int indent)
 207 {
 208     switch (qobject_type(obj)) {
 209     case QTYPE_QNULL:
 210         qstring_append(str, "null");
 211         break;
 212     case QTYPE_QNUM: {
 213         QNum *val = qobject_to(QNum, obj);
 214         char *buffer = qnum_to_string(val);
 215         qstring_append(str, buffer);
 216         g_free(buffer);
 217         break;
 218     }
 219     case QTYPE_QSTRING: {
 220         QString *val = qobject_to(QString, obj);
 221         const char *ptr;
 222         int cp;
 223         char buf[16];
 224         char *end;
 225
 226         ptr = qstring_get_str(val);
 227         qstring_append(str, "\"");
 228
 229         for (; *ptr; ptr = end) {
 230             cp = mod_utf8_codepoint(ptr, 6, &end);
 231             switch (cp) {
 232             case '\"':
 233                 qstring_append(str, "\\\"");
 234                 break;
 235             case '\\':
 236                 qstring_append(str, "\\\\");
 237                 break;
 238             case '\b':
 239                 qstring_append(str, "\\b");
 240                 break;
 241             case '\f':
 242                 qstring_append(str, "\\f");
 243                 break;
 244             case '\n':
 245                 qstring_append(str, "\\n");
 246                 break;
 247             case '\r':
 248                 qstring_append(str, "\\r");
 249                 break;
 250             case '\t':
 251                 qstring_append(str, "\\t");
 252                 break;
 253             default:
 254                 if (cp < 0) {
 255                     cp = 0xFFFD; /* replacement character */
 256                 }
 257                 if (cp > 0xFFFF) {
 258                     /* beyond BMP; need a surrogate pair */
 259                     snprintf(buf, sizeof(buf), "\\u%04X\\u%04X",
 260                              0xD800 + ((cp - 0x10000) >> 10),
 261                              0xDC00 + ((cp - 0x10000) & 0x3FF));
 262                 } else if (cp < 0x20 || cp >= 0x7F) {
 263                     snprintf(buf, sizeof(buf), "\\u%04X", cp);
 264                 } else {
 265                     buf[0] = cp;
 266                     buf[1] = 0;
 267                 }
 268                 qstring_append(str, buf);
 269             }
 270         };
 271
 272         qstring_append(str, "\"");
 273         break;
 274     }
 275     case QTYPE_QDICT: {
 276         ToJsonIterState s;
 277         QDict *val = qobject_to(QDict, obj);
 278
 279         s.count = 0;
 280         s.str = str;
 281         s.indent = indent + 1;
 282         s.pretty = pretty;
 283         qstring_append(str, "{");
 284         qdict_iter(val, to_json_dict_iter, &s);
 285         if (pretty) {
 286             int j;
 287             qstring_append(str, "\n");
 288             for (j = 0 ; j < indent ; j++)
 289                 qstring_append(str, "    ");
 290         }
 291         qstring_append(str, "}");
 292         break;
 293     }
 294     case QTYPE_QLIST: {
 295         ToJsonIterState s;
 296         QList *val = qobject_to(QList, obj);
 297
 298         s.count = 0;
 299         s.str = str;
 300         s.indent = indent + 1;
 301         s.pretty = pretty;
 302         qstring_append(str, "[");
 303         qlist_iter(val, (void *)to_json_list_iter, &s);
 304         if (pretty) {
 305             int j;
 306             qstring_append(str, "\n");
 307             for (j = 0 ; j < indent ; j++)
 308                 qstring_append(str, "    ");
 309         }
 310         qstring_append(str, "]");
 311         break;
 312     }
 313     case QTYPE_QBOOL: {
 314         QBool *val = qobject_to(QBool, obj);
 315
 316         if (qbool_get_bool(val)) {
 317             qstring_append(str, "true");
 318         } else {
 319             qstring_append(str, "false");
 320         }
 321         break;
 322     }
 323     default:
 324         abort();
 325     }
 326 }
 327
 328 QString *qobject_to_json(const QObject *obj)
 329 {
 330     QString *str = qstring_new();
 331
 332     to_json(obj, str, 0, 0);
 333
 334     return str;
 335 }
 336
 337 QString *qobject_to_json_pretty(const QObject *obj)
 338 {
 339     QString *str = qstring_new();
 340
 341     to_json(obj, str, 1, 0);
 342
 343     return str;
 344 }