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/json-writer.h" 18 #include "qapi/qmp/qjson.h" 19 #include "qapi/qmp/qbool.h" 20 #include "qapi/qmp/qdict.h" 21 #include "qapi/qmp/qlist.h" 22 #include "qapi/qmp/qnum.h" 23 #include "qapi/qmp/qstring.h" 24 25 typedef struct JSONParsingState { 26 JSONMessageParser parser; 27 QObject *result; 28 Error *err; 29 } JSONParsingState; 30 31 static void consume_json(void *opaque, QObject *json, Error *err) 32 { 33 JSONParsingState *s = opaque; 34 35 assert(!json != !err); 36 assert(!s->result || !s->err); 37 38 if (s->result) { 39 qobject_unref(s->result); 40 s->result = NULL; 41 error_setg(&s->err, "Expecting at most one JSON value"); 42 } 43 if (s->err) { 44 qobject_unref(json); 45 error_free(err); 46 return; 47 } 48 s->result = json; 49 s->err = err; 50 } 51 52 /* 53 * Parse @string as JSON value. 54 * If @ap is non-null, interpolate %-escapes. 55 * Takes ownership of %p arguments. 56 * On success, return the JSON value. 57 * On failure, store an error through @errp and return NULL. 58 * Ownership of %p arguments becomes indeterminate then. To avoid 59 * leaks, callers passing %p must terminate on error, e.g. by passing 60 * &error_abort. 61 */ 62 static QObject *qobject_from_jsonv(const char *string, va_list *ap, 63 Error **errp) 64 { 65 JSONParsingState state = {}; 66 67 json_message_parser_init(&state.parser, consume_json, &state, ap); 68 json_message_parser_feed(&state.parser, string, strlen(string)); 69 json_message_parser_flush(&state.parser); 70 json_message_parser_destroy(&state.parser); 71 72 if (!state.result && !state.err) { 73 error_setg(&state.err, "Expecting a JSON value"); 74 } 75 76 error_propagate(errp, state.err); 77 return state.result; 78 } 79 80 QObject *qobject_from_json(const char *string, Error **errp) 81 { 82 return qobject_from_jsonv(string, NULL, errp); 83 } 84 85 /* 86 * Parse @string as JSON value with %-escapes interpolated. 87 * Abort on error. Do not use with untrusted @string. 88 * Return the resulting QObject. It is never null. 89 */ 90 QObject *qobject_from_vjsonf_nofail(const char *string, va_list ap) 91 { 92 va_list ap_copy; 93 QObject *obj; 94 95 /* va_copy() is needed when va_list is an array type */ 96 va_copy(ap_copy, ap); 97 obj = qobject_from_jsonv(string, &ap_copy, &error_abort); 98 va_end(ap_copy); 99 100 assert(obj); 101 return obj; 102 } 103 104 /* 105 * Parse @string as JSON value with %-escapes interpolated. 106 * Abort on error. Do not use with untrusted @string. 107 * Return the resulting QObject. It is never null. 108 */ 109 QObject *qobject_from_jsonf_nofail(const char *string, ...) 110 { 111 QObject *obj; 112 va_list ap; 113 114 va_start(ap, string); 115 obj = qobject_from_vjsonf_nofail(string, ap); 116 va_end(ap); 117 118 return obj; 119 } 120 121 /* 122 * Parse @string as JSON object with %-escapes interpolated. 123 * Abort on error. Do not use with untrusted @string. 124 * Return the resulting QDict. It is never null. 125 */ 126 QDict *qdict_from_vjsonf_nofail(const char *string, va_list ap) 127 { 128 QDict *qdict; 129 130 qdict = qobject_to(QDict, qobject_from_vjsonf_nofail(string, ap)); 131 assert(qdict); 132 return qdict; 133 } 134 135 /* 136 * Parse @string as JSON object with %-escapes interpolated. 137 * Abort on error. Do not use with untrusted @string. 138 * Return the resulting QDict. It is never null. 139 */ 140 QDict *qdict_from_jsonf_nofail(const char *string, ...) 141 { 142 QDict *qdict; 143 va_list ap; 144 145 va_start(ap, string); 146 qdict = qdict_from_vjsonf_nofail(string, ap); 147 va_end(ap); 148 return qdict; 149 } 150 151 static void to_json(JSONWriter *writer, const char *name, 152 const QObject *obj) 153 { 154 switch (qobject_type(obj)) { 155 case QTYPE_QNULL: 156 json_writer_null(writer, name); 157 break; 158 case QTYPE_QNUM: { 159 QNum *val = qobject_to(QNum, obj); 160 161 switch (val->kind) { 162 case QNUM_I64: 163 json_writer_int64(writer, name, val->u.i64); 164 break; 165 case QNUM_U64: 166 json_writer_uint64(writer, name, val->u.u64); 167 break; 168 case QNUM_DOUBLE: 169 json_writer_double(writer, name, val->u.dbl); 170 break; 171 default: 172 abort(); 173 } 174 break; 175 } 176 case QTYPE_QSTRING: { 177 QString *val = qobject_to(QString, obj); 178 179 json_writer_str(writer, name, qstring_get_str(val)); 180 break; 181 } 182 case QTYPE_QDICT: { 183 QDict *val = qobject_to(QDict, obj); 184 const QDictEntry *entry; 185 186 json_writer_start_object(writer, name); 187 188 for (entry = qdict_first(val); 189 entry; 190 entry = qdict_next(val, entry)) { 191 to_json(writer, qdict_entry_key(entry), qdict_entry_value(entry)); 192 } 193 194 json_writer_end_object(writer); 195 break; 196 } 197 case QTYPE_QLIST: { 198 QList *val = qobject_to(QList, obj); 199 QListEntry *entry; 200 201 json_writer_start_array(writer, name); 202 203 QLIST_FOREACH_ENTRY(val, entry) { 204 to_json(writer, NULL, qlist_entry_obj(entry)); 205 } 206 207 json_writer_end_array(writer); 208 break; 209 } 210 case QTYPE_QBOOL: { 211 QBool *val = qobject_to(QBool, obj); 212 213 json_writer_bool(writer, name, qbool_get_bool(val)); 214 break; 215 } 216 default: 217 abort(); 218 } 219 } 220 221 GString *qobject_to_json_pretty(const QObject *obj, bool pretty) 222 { 223 JSONWriter *writer = json_writer_new(pretty); 224 225 to_json(writer, NULL, obj); 226 return json_writer_get_and_free(writer); 227 } 228 229 GString *qobject_to_json(const QObject *obj) 230 { 231 return qobject_to_json_pretty(obj, false); 232 } 233