qemu

qjson.c (5848B)

---

 /*
  * QObject JSON integration
  *
  * Copyright IBM, Corp. 2009
  *
  * Authors:
  *  Anthony Liguori   <aliguori@us.ibm.com>
  *
  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
  * See the COPYING.LIB file in the top-level directory.
  *
  */
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qapi/qmp/json-parser.h"
 #include "qapi/qmp/json-writer.h"
 #include "qapi/qmp/qjson.h"
 #include "qapi/qmp/qbool.h"
 #include "qapi/qmp/qdict.h"
 #include "qapi/qmp/qlist.h"
 #include "qapi/qmp/qnum.h"
 #include "qapi/qmp/qstring.h"
 
 typedef struct JSONParsingState {
     JSONMessageParser parser;
     QObject *result;
     Error *err;
 } JSONParsingState;
 
 static void consume_json(void *opaque, QObject *json, Error *err)
 {
     JSONParsingState *s = opaque;
 
     assert(!json != !err);
     assert(!s->result || !s->err);
 
     if (s->result) {
         qobject_unref(s->result);
         s->result = NULL;
         error_setg(&s->err, "Expecting at most one JSON value");
     }
     if (s->err) {
         qobject_unref(json);
         error_free(err);
         return;
     }
     s->result = json;
     s->err = err;
 }
 
 /*
  * Parse @string as JSON value.
  * If @ap is non-null, interpolate %-escapes.
  * Takes ownership of %p arguments.
  * On success, return the JSON value.
  * On failure, store an error through @errp and return NULL.
  * Ownership of %p arguments becomes indeterminate then.  To avoid
  * leaks, callers passing %p must terminate on error, e.g. by passing
  * &error_abort.
  */
 static QObject *qobject_from_jsonv(const char *string, va_list *ap,
                                    Error **errp)
 {
     JSONParsingState state = {};
 
     json_message_parser_init(&state.parser, consume_json, &state, ap);
     json_message_parser_feed(&state.parser, string, strlen(string));
     json_message_parser_flush(&state.parser);
     json_message_parser_destroy(&state.parser);
 
     if (!state.result && !state.err) {
         error_setg(&state.err, "Expecting a JSON value");
     }
 
     error_propagate(errp, state.err);
     return state.result;
 }
 
 QObject *qobject_from_json(const char *string, Error **errp)
 {
     return qobject_from_jsonv(string, NULL, errp);
 }
 
 /*
  * Parse @string as JSON value with %-escapes interpolated.
  * Abort on error.  Do not use with untrusted @string.
  * Return the resulting QObject.  It is never null.
  */
 QObject *qobject_from_vjsonf_nofail(const char *string, va_list ap)
 {
     va_list ap_copy;
     QObject *obj;
 
     /* va_copy() is needed when va_list is an array type */
     va_copy(ap_copy, ap);
     obj = qobject_from_jsonv(string, &ap_copy, &error_abort);
     va_end(ap_copy);
 
     assert(obj);
     return obj;
 }
 
 /*
  * Parse @string as JSON value with %-escapes interpolated.
  * Abort on error.  Do not use with untrusted @string.
  * Return the resulting QObject.  It is never null.
  */
 QObject *qobject_from_jsonf_nofail(const char *string, ...)
 {
     QObject *obj;
     va_list ap;
 
     va_start(ap, string);
     obj = qobject_from_vjsonf_nofail(string, ap);
     va_end(ap);
 
     return obj;
 }
 
 /*
  * Parse @string as JSON object with %-escapes interpolated.
  * Abort on error.  Do not use with untrusted @string.
  * Return the resulting QDict.  It is never null.
  */
 QDict *qdict_from_vjsonf_nofail(const char *string, va_list ap)
 {
     QDict *qdict;
 
     qdict = qobject_to(QDict, qobject_from_vjsonf_nofail(string, ap));
     assert(qdict);
     return qdict;
 }
 
 /*
  * Parse @string as JSON object with %-escapes interpolated.
  * Abort on error.  Do not use with untrusted @string.
  * Return the resulting QDict.  It is never null.
  */
 QDict *qdict_from_jsonf_nofail(const char *string, ...)
 {
     QDict *qdict;
     va_list ap;
 
     va_start(ap, string);
     qdict = qdict_from_vjsonf_nofail(string, ap);
     va_end(ap);
     return qdict;
 }
 
 static void to_json(JSONWriter *writer, const char *name,
                     const QObject *obj)
 {
     switch (qobject_type(obj)) {
     case QTYPE_QNULL:
         json_writer_null(writer, name);
         break;
     case QTYPE_QNUM: {
         QNum *val = qobject_to(QNum, obj);
 
         switch (val->kind) {
         case QNUM_I64:
             json_writer_int64(writer, name, val->u.i64);
             break;
         case QNUM_U64:
             json_writer_uint64(writer, name, val->u.u64);
             break;
         case QNUM_DOUBLE:
             json_writer_double(writer, name, val->u.dbl);
             break;
         default:
             abort();
         }
         break;
     }
     case QTYPE_QSTRING: {
         QString *val = qobject_to(QString, obj);
 
         json_writer_str(writer, name, qstring_get_str(val));
         break;
     }
     case QTYPE_QDICT: {
         QDict *val = qobject_to(QDict, obj);
         const QDictEntry *entry;
 
         json_writer_start_object(writer, name);
 
         for (entry = qdict_first(val);
              entry;
              entry = qdict_next(val, entry)) {
             to_json(writer, qdict_entry_key(entry), qdict_entry_value(entry));
         }
 
         json_writer_end_object(writer);
         break;
     }
     case QTYPE_QLIST: {
         QList *val = qobject_to(QList, obj);
         QListEntry *entry;
 
         json_writer_start_array(writer, name);
 
         QLIST_FOREACH_ENTRY(val, entry) {
             to_json(writer, NULL, qlist_entry_obj(entry));
         }
 
         json_writer_end_array(writer);
         break;
     }
     case QTYPE_QBOOL: {
         QBool *val = qobject_to(QBool, obj);
 
         json_writer_bool(writer, name, qbool_get_bool(val));
         break;
     }
     default:
         abort();
     }
 }
 
 GString *qobject_to_json_pretty(const QObject *obj, bool pretty)
 {
     JSONWriter *writer = json_writer_new(pretty);
 
     to_json(writer, NULL, obj);
     return json_writer_get_and_free(writer);
 }
 
 GString *qobject_to_json(const QObject *obj)
 {
     return qobject_to_json_pretty(obj, false);
 }