qemu/qobject/qjson.c
Markus Armbruster eab3a4678b qobject: Change qobject_to_json()'s value to GString
qobject_to_json() and qobject_to_json_pretty() build a GString, then
covert it to QString.  Just one of the callers actually needs a
QString: qemu_rbd_parse_filename().  A few others need a string they
can modify: qmp_send_response(), qga's send_response(), to_json_str(),
and qmp_fd_vsend_fds().  The remainder just need a string.

Change qobject_to_json() and qobject_to_json_pretty() to return the
GString.

qemu_rbd_parse_filename() now has to convert to QString.  All others
save a QString temporary.  to_json_str() actually becomes a bit
simpler, because GString provides more convenient modification
functions.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201211171152.146877-6-armbru@redhat.com>
2020-12-19 10:38:43 +01:00

299 lines
7.8 KiB
C

/*
* 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/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"
#include "qemu/unicode.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 json_pretty_newline(GString *accu, bool pretty, int indent)
{
if (pretty) {
g_string_append_printf(accu, "\n%*s", indent * 4, "");
}
}
static void to_json(const QObject *obj, GString *accu, bool pretty, int indent)
{
switch (qobject_type(obj)) {
case QTYPE_QNULL:
g_string_append(accu, "null");
break;
case QTYPE_QNUM: {
QNum *val = qobject_to(QNum, obj);
char *buffer = qnum_to_string(val);
g_string_append(accu, buffer);
g_free(buffer);
break;
}
case QTYPE_QSTRING: {
QString *val = qobject_to(QString, obj);
const char *ptr;
int cp;
char *end;
ptr = qstring_get_str(val);
g_string_append_c(accu, '"');
for (; *ptr; ptr = end) {
cp = mod_utf8_codepoint(ptr, 6, &end);
switch (cp) {
case '\"':
g_string_append(accu, "\\\"");
break;
case '\\':
g_string_append(accu, "\\\\");
break;
case '\b':
g_string_append(accu, "\\b");
break;
case '\f':
g_string_append(accu, "\\f");
break;
case '\n':
g_string_append(accu, "\\n");
break;
case '\r':
g_string_append(accu, "\\r");
break;
case '\t':
g_string_append(accu, "\\t");
break;
default:
if (cp < 0) {
cp = 0xFFFD; /* replacement character */
}
if (cp > 0xFFFF) {
/* beyond BMP; need a surrogate pair */
g_string_append_printf(accu, "\\u%04X\\u%04X",
0xD800 + ((cp - 0x10000) >> 10),
0xDC00 + ((cp - 0x10000) & 0x3FF));
} else if (cp < 0x20 || cp >= 0x7F) {
g_string_append_printf(accu, "\\u%04X", cp);
} else {
g_string_append_c(accu, cp);
}
}
};
g_string_append_c(accu, '"');
break;
}
case QTYPE_QDICT: {
QDict *val = qobject_to(QDict, obj);
const char *comma = pretty ? "," : ", ";
const char *sep = "";
const QDictEntry *entry;
QString *qkey;
g_string_append_c(accu, '{');
for (entry = qdict_first(val);
entry;
entry = qdict_next(val, entry)) {
g_string_append(accu, sep);
json_pretty_newline(accu, pretty, indent + 1);
qkey = qstring_from_str(qdict_entry_key(entry));
to_json(QOBJECT(qkey), accu, pretty, indent + 1);
qobject_unref(qkey);
g_string_append(accu, ": ");
to_json(qdict_entry_value(entry), accu, pretty, indent + 1);
sep = comma;
}
json_pretty_newline(accu, pretty, indent);
g_string_append_c(accu, '}');
break;
}
case QTYPE_QLIST: {
QList *val = qobject_to(QList, obj);
const char *comma = pretty ? "," : ", ";
const char *sep = "";
QListEntry *entry;
g_string_append_c(accu, '[');
QLIST_FOREACH_ENTRY(val, entry) {
g_string_append(accu, sep);
json_pretty_newline(accu, pretty, indent + 1);
to_json(qlist_entry_obj(entry), accu, pretty, indent + 1);
sep = comma;
}
json_pretty_newline(accu, pretty, indent);
g_string_append_c(accu, ']');
break;
}
case QTYPE_QBOOL: {
QBool *val = qobject_to(QBool, obj);
if (qbool_get_bool(val)) {
g_string_append(accu, "true");
} else {
g_string_append(accu, "false");
}
break;
}
default:
abort();
}
}
GString *qobject_to_json_pretty(const QObject *obj, bool pretty)
{
GString *accu = g_string_new(NULL);
to_json(obj, accu, pretty, 0);
return accu;
}
GString *qobject_to_json(const QObject *obj)
{
return qobject_to_json_pretty(obj, false);
}