qjson: Fix qobject_from_json() & friends for multiple values

[qemu.git] / qobject / qjson.c

diff --git a/qobject/qjson.c b/qobject/qjson.c
index 2e0930884e5dc7224e879ef1567f18d85cd6558a..7f6903648723a1aa9528190f3af980f5134a6fc1 100644 (file)
--- a/qobject/qjson.c
+++ b/qobject/qjson.c
@@ -13,35 +13,59 @@
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
-#include "qapi/qmp/json-lexer.h"
-#include "qapi/qmp/json-parser.h"
 #include "qapi/qmp/json-streamer.h"
 #include "qapi/qmp/qjson.h"
-#include "qapi/qmp/types.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"
 #include "qemu/unicode.h"
 
 typedef struct JSONParsingState
 {
     JSONMessageParser parser;
-    va_list *ap;
     QObject *result;
     Error *err;
 } JSONParsingState;
 
-static void parse_json(JSONMessageParser *parser, GQueue *tokens)
+static void consume_json(void *opaque, QObject *json, Error *err)
 {
-    JSONParsingState *s = container_of(parser, JSONParsingState, parser);
+    JSONParsingState *s = opaque;
 
-    s->result = json_parser_parse_err(tokens, s->ap, &s->err);
+    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;
 }
 
-QObject *qobject_from_jsonv(const char *string, va_list *ap, Error **errp)
+/*
+ * 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 = {};
 
-    state.ap = ap;
-
-    json_message_parser_init(&state.parser, parse_json);
+    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);
@@ -56,22 +80,71 @@ QObject *qobject_from_json(const char *string, Error **errp)
 }
 
 /*
- * IMPORTANT: This function aborts on error, thus it must not
- * be used with untrusted arguments.
+ * 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(const char *string, ...)
+QObject *qobject_from_jsonf_nofail(const char *string, ...)
 {
     QObject *obj;
     va_list ap;
 
     va_start(ap, string);
-    obj = qobject_from_jsonv(string, &ap, &error_abort);
+    obj = qobject_from_vjsonf_nofail(string, ap);
     va_end(ap);
 
-    assert(obj != NULL);
     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;
+}
+
 typedef struct ToJsonIterState
 {
     int indent;
@@ -100,7 +173,7 @@ static void to_json_dict_iter(const char *key, QObject *obj, void *opaque)
 
     qkey = qstring_from_str(key);
     to_json(QOBJECT(qkey), s->str, s->pretty, s->indent);
-    QDECREF(qkey);
+    qobject_unref(qkey);
 
     qstring_append(s->str, ": ");
     to_json(obj, s->str, s->pretty, s->indent);
@@ -133,14 +206,14 @@ static void to_json(const QObject *obj, QString *str, int pretty, int indent)
         qstring_append(str, "null");
         break;
     case QTYPE_QNUM: {
-        QNum *val = qobject_to_qnum(obj);
+        QNum *val = qobject_to(QNum, obj);
         char *buffer = qnum_to_string(val);
         qstring_append(str, buffer);
         g_free(buffer);
         break;
     }
     case QTYPE_QSTRING: {
-        QString *val = qobject_to_qstring(obj);
+        QString *val = qobject_to(QString, obj);
         const char *ptr;
         int cp;
         char buf[16];
@@ -197,7 +270,7 @@ static void to_json(const QObject *obj, QString *str, int pretty, int indent)
     }
     case QTYPE_QDICT: {
         ToJsonIterState s;
-        QDict *val = qobject_to_qdict(obj);
+        QDict *val = qobject_to(QDict, obj);
 
         s.count = 0;
         s.str = str;
@@ -216,7 +289,7 @@ static void to_json(const QObject *obj, QString *str, int pretty, int indent)
     }
     case QTYPE_QLIST: {
         ToJsonIterState s;
-        QList *val = qobject_to_qlist(obj);
+        QList *val = qobject_to(QList, obj);
 
         s.count = 0;
         s.str = str;
@@ -234,7 +307,7 @@ static void to_json(const QObject *obj, QString *str, int pretty, int indent)
         break;
     }
     case QTYPE_QBOOL: {
-        QBool *val = qobject_to_qbool(obj);
+        QBool *val = qobject_to(QBool, obj);
 
         if (qbool_get_bool(val)) {
             qstring_append(str, "true");