xref: /qemu/qobject/qjson.c (revision 5b76dd13) 
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 }
345