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