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qemu/qapi/qmp-input-visitor.c
Eric Blake 15c2f669e3 qapi: Split visit_end_struct() into pieces 
As mentioned in previous patches, we want to call visit_end_struct()
functions unconditionally, so that visitors can release resources
tied up since the matching visit_start_struct() without also having
to worry about error priority if more than one error occurs.

Even though error_propagate() can be safely used to ignore a second
error during cleanup caused by a first error, it is simpler if the
cleanup cannot set an error.  So, split out the error checking
portion (basically, input visitors checking for unvisited keys) into
a new function visit_check_struct(), which can be safely skipped if
any earlier errors are encountered, and leave the cleanup portion
(which never fails, but must be called unconditionally if
visit_start_struct() succeeded) in visit_end_struct().

Generated code in qapi-visit.c has diffs resembling:

|@@ -59,10 +59,12 @@ void visit_type_ACPIOSTInfo(Visitor *v,
|         goto out_obj;
|     }
|     visit_type_ACPIOSTInfo_members(v, obj, &err);
|-    error_propagate(errp, err);
|-    err = NULL;
|+    if (err) {
|+        goto out_obj;
|+    }
|+    visit_check_struct(v, &err);
| out_obj:
|-    visit_end_struct(v, &err);
|+    visit_end_struct(v);
| out:

and in qapi-event.c:

@@ -47,7 +47,10 @@ void qapi_event_send_acpi_device_ost(ACP
|         goto out;
|     }
|     visit_type_q_obj_ACPI_DEVICE_OST_arg_members(v, &param, &err);
|-    visit_end_struct(v, err ? NULL : &err);
|+    if (!err) {
|+        visit_check_struct(v, &err);
|+    }
|+    visit_end_struct(v);
|     if (err) {
|         goto out;

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1461879932-9020-20-git-send-email-eblake@redhat.com>
[Conflict with a doc fixup resolved]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-05-12 09:47:55 +02:00

411 lines
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/*
* Input Visitor
*
* Copyright (C) 2012-2016 Red Hat, Inc.
* Copyright IBM, Corp. 2011
*
* 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-input-visitor.h"
#include "qapi/visitor-impl.h"
#include "qemu/queue.h"
#include "qemu-common.h"
#include "qapi/qmp/types.h"
#include "qapi/qmp/qerror.h"
#define QIV_STACK_SIZE 1024
typedef struct StackObject
{
QObject *obj; /* Object being visited */
GHashTable *h; /* If obj is dict: unvisited keys */
const QListEntry *entry; /* If obj is list: unvisited tail */
bool first; /* If obj is list: next_list() not yet called? */
} StackObject;
struct QmpInputVisitor
{
Visitor visitor;
/* Root of visit at visitor creation. */
QObject *root;
/* Stack of objects being visited (all entries will be either
* QDict or QList). */
StackObject stack[QIV_STACK_SIZE];
int nb_stack;
/* True to reject parse in visit_end_struct() if unvisited keys remain. */
bool strict;
};
static QmpInputVisitor *to_qiv(Visitor *v)
{
return container_of(v, QmpInputVisitor, visitor);
}
static QObject *qmp_input_get_object(QmpInputVisitor *qiv,
const char *name,
bool consume)
{
StackObject *tos;
QObject *qobj;
QObject *ret;
if (!qiv->nb_stack) {
/* Starting at root, name is ignored. */
return qiv->root;
}
/* We are in a container; find the next element. */
tos = &qiv->stack[qiv->nb_stack - 1];
qobj = tos->obj;
assert(qobj);
if (qobject_type(qobj) == QTYPE_QDICT) {
assert(name);
ret = qdict_get(qobject_to_qdict(qobj), name);
if (tos->h && consume && ret) {
bool removed = g_hash_table_remove(tos->h, name);
assert(removed);
}
} else {
assert(qobject_type(qobj) == QTYPE_QLIST);
assert(!name);
assert(!tos->first);
ret = qlist_entry_obj(tos->entry);
if (consume) {
tos->entry = qlist_next(tos->entry);
}
}
return ret;
}
static void qdict_add_key(const char *key, QObject *obj, void *opaque)
{
GHashTable *h = opaque;
g_hash_table_insert(h, (gpointer) key, NULL);
}
static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp)
{
GHashTable *h;
StackObject *tos = &qiv->stack[qiv->nb_stack];
assert(obj);
if (qiv->nb_stack >= QIV_STACK_SIZE) {
error_setg(errp, "An internal buffer overran");
return;
}
tos->obj = obj;
assert(!tos->h);
assert(!tos->entry);
if (qiv->strict && qobject_type(obj) == QTYPE_QDICT) {
h = g_hash_table_new(g_str_hash, g_str_equal);
qdict_iter(qobject_to_qdict(obj), qdict_add_key, h);
tos->h = h;
} else if (qobject_type(obj) == QTYPE_QLIST) {
tos->entry = qlist_first(qobject_to_qlist(obj));
tos->first = true;
}
qiv->nb_stack++;
}
static void qmp_input_check_struct(Visitor *v, Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
StackObject *tos = &qiv->stack[qiv->nb_stack - 1];
assert(qiv->nb_stack > 0);
if (qiv->strict) {
GHashTable *const top_ht = tos->h;
if (top_ht) {
GHashTableIter iter;
const char *key;
g_hash_table_iter_init(&iter, top_ht);
if (g_hash_table_iter_next(&iter, (void **)&key, NULL)) {
error_setg(errp, QERR_QMP_EXTRA_MEMBER, key);
}
}
}
}
static void qmp_input_pop(Visitor *v)
{
QmpInputVisitor *qiv = to_qiv(v);
StackObject *tos = &qiv->stack[qiv->nb_stack - 1];
assert(qiv->nb_stack > 0);
if (qiv->strict) {
GHashTable * const top_ht = qiv->stack[qiv->nb_stack - 1].h;
if (top_ht) {
g_hash_table_unref(top_ht);
}
tos->h = NULL;
}
qiv->nb_stack--;
}
static void qmp_input_start_struct(Visitor *v, const char *name, void **obj,
size_t size, Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QObject *qobj = qmp_input_get_object(qiv, name, true);
Error *err = NULL;
if (obj) {
*obj = NULL;
}
if (!qobj || qobject_type(qobj) != QTYPE_QDICT) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"QDict");
return;
}
qmp_input_push(qiv, qobj, &err);
if (err) {
error_propagate(errp, err);
return;
}
if (obj) {
*obj = g_malloc0(size);
}
}
static void qmp_input_start_list(Visitor *v, const char *name, Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QObject *qobj = qmp_input_get_object(qiv, name, true);
if (!qobj || qobject_type(qobj) != QTYPE_QLIST) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"list");
return;
}
qmp_input_push(qiv, qobj, errp);
}
static GenericList *qmp_input_next_list(Visitor *v, GenericList **list,
size_t size)
{
QmpInputVisitor *qiv = to_qiv(v);
GenericList *entry;
StackObject *so = &qiv->stack[qiv->nb_stack - 1];
if (!so->entry) {
return NULL;
}
entry = g_malloc0(size);
if (so->first) {
*list = entry;
so->first = false;
} else {
(*list)->next = entry;
}
return entry;
}
static void qmp_input_start_alternate(Visitor *v, const char *name,
GenericAlternate **obj, size_t size,
bool promote_int, Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QObject *qobj = qmp_input_get_object(qiv, name, false);
if (!qobj) {
*obj = NULL;
error_setg(errp, QERR_MISSING_PARAMETER, name ? name : "null");
return;
}
*obj = g_malloc0(size);
(*obj)->type = qobject_type(qobj);
if (promote_int && (*obj)->type == QTYPE_QINT) {
(*obj)->type = QTYPE_QFLOAT;
}
}
static void qmp_input_type_int64(Visitor *v, const char *name, int64_t *obj,
Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QInt *qint = qobject_to_qint(qmp_input_get_object(qiv, name, true));
if (!qint) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"integer");
return;
}
*obj = qint_get_int(qint);
}
static void qmp_input_type_uint64(Visitor *v, const char *name, uint64_t *obj,
Error **errp)
{
/* FIXME: qobject_to_qint mishandles values over INT64_MAX */
QmpInputVisitor *qiv = to_qiv(v);
QInt *qint = qobject_to_qint(qmp_input_get_object(qiv, name, true));
if (!qint) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"integer");
return;
}
*obj = qint_get_int(qint);
}
static void qmp_input_type_bool(Visitor *v, const char *name, bool *obj,
Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QBool *qbool = qobject_to_qbool(qmp_input_get_object(qiv, name, true));
if (!qbool) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"boolean");
return;
}
*obj = qbool_get_bool(qbool);
}
static void qmp_input_type_str(Visitor *v, const char *name, char **obj,
Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QString *qstr = qobject_to_qstring(qmp_input_get_object(qiv, name, true));
if (!qstr) {
*obj = NULL;
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"string");
return;
}
*obj = g_strdup(qstring_get_str(qstr));
}
static void qmp_input_type_number(Visitor *v, const char *name, double *obj,
Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QObject *qobj = qmp_input_get_object(qiv, name, true);
QInt *qint;
QFloat *qfloat;
qint = qobject_to_qint(qobj);
if (qint) {
*obj = qint_get_int(qobject_to_qint(qobj));
return;
}
qfloat = qobject_to_qfloat(qobj);
if (qfloat) {
*obj = qfloat_get_double(qobject_to_qfloat(qobj));
return;
}
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"number");
}
static void qmp_input_type_any(Visitor *v, const char *name, QObject **obj,
Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QObject *qobj = qmp_input_get_object(qiv, name, true);
qobject_incref(qobj);
*obj = qobj;
}
static void qmp_input_type_null(Visitor *v, const char *name, Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
QObject *qobj = qmp_input_get_object(qiv, name, true);
if (qobject_type(qobj) != QTYPE_QNULL) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"null");
}
}
static void qmp_input_optional(Visitor *v, const char *name, bool *present)
{
QmpInputVisitor *qiv = to_qiv(v);
QObject *qobj = qmp_input_get_object(qiv, name, false);
if (!qobj) {
*present = false;
return;
}
*present = true;
}
Visitor *qmp_input_get_visitor(QmpInputVisitor *v)
{
return &v->visitor;
}
void qmp_input_visitor_cleanup(QmpInputVisitor *v)
{
qobject_decref(v->root);
g_free(v);
}
QmpInputVisitor *qmp_input_visitor_new(QObject *obj, bool strict)
{
QmpInputVisitor *v;
v = g_malloc0(sizeof(*v));
v->visitor.type = VISITOR_INPUT;
v->visitor.start_struct = qmp_input_start_struct;
v->visitor.check_struct = qmp_input_check_struct;
v->visitor.end_struct = qmp_input_pop;
v->visitor.start_list = qmp_input_start_list;
v->visitor.next_list = qmp_input_next_list;
v->visitor.end_list = qmp_input_pop;
v->visitor.start_alternate = qmp_input_start_alternate;
v->visitor.type_int64 = qmp_input_type_int64;
v->visitor.type_uint64 = qmp_input_type_uint64;
v->visitor.type_bool = qmp_input_type_bool;
v->visitor.type_str = qmp_input_type_str;
v->visitor.type_number = qmp_input_type_number;
v->visitor.type_any = qmp_input_type_any;
v->visitor.type_null = qmp_input_type_null;
v->visitor.optional = qmp_input_optional;
v->strict = strict;
v->root = obj;
qobject_incref(obj);
return v;
}
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