Re: [Qemu-devel] [PATCH v3 07/21] qapi: add QAPI dealloc visitor

[Luiz Capitulino <lcapitulino@redhat.com>]

On Mon, 13 Jun 2011 21:31:12 -0500
Michael Roth <mdroth@linux.vnet.ibm.com> wrote:

> Type of Visitor class that can be passed into a qapi-generated C
> type's visitor function to free() any heap-allocated data types.
> 
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> ---
>  Makefile.objs               |    2 +-
>  qapi/qapi-dealloc-visitor.c |  127 +++++++++++++++++++++++++++++++++++++++++++
>  qapi/qapi-dealloc-visitor.h |   26 +++++++++
>  3 files changed, 154 insertions(+), 1 deletions(-)
>  create mode 100644 qapi/qapi-dealloc-visitor.c
>  create mode 100644 qapi/qapi-dealloc-visitor.h
> 
> diff --git a/Makefile.objs b/Makefile.objs
> index af302ea..3860252 100644
> --- a/Makefile.objs
> +++ b/Makefile.objs
> @@ -367,7 +367,7 @@ libcacard-y = cac.o event.o vcard.o vreader.o vcard_emul_nss.o vcard_emul_type.o
>  ######################################################################
>  # qapi
>  
> -qapi-nested-y = qapi-visit-core.o qmp-input-visitor.o qmp-output-visitor.o
> +qapi-nested-y = qapi-visit-core.o qmp-input-visitor.o qmp-output-visitor.o qapi-dealloc-visitor.o
>  qapi-obj-y = $(addprefix qapi/, $(qapi-nested-y))
>  
>  vl.o: QEMU_CFLAGS+=$(GPROF_CFLAGS)
> diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
> new file mode 100644
> index 0000000..1fabfe6
> --- /dev/null
> +++ b/qapi/qapi-dealloc-visitor.c
> @@ -0,0 +1,127 @@
> +#include "qapi-dealloc-visitor.h"
> +#include "qemu-queue.h"
> +#include "qemu-common.h"
> +#include "qemu-objects.h"
> +
> +typedef struct StackEntry
> +{
> +    void *value;
> +    QTAILQ_ENTRY(StackEntry) node;
> +} StackEntry;
> +
> +struct QapiDeallocVisitor
> +{
> +    Visitor visitor;
> +    QTAILQ_HEAD(, StackEntry) stack;
> +};
> +
> +static QapiDeallocVisitor *to_qov(Visitor *v)
> +{
> +    return container_of(v, QapiDeallocVisitor, visitor);
> +}
> +
> +static void qapi_dealloc_push(QapiDeallocVisitor *qov, void *value)
> +{
> +    StackEntry *e = qemu_mallocz(sizeof(*e));
> +
> +    e->value = value;
> +    QTAILQ_INSERT_HEAD(&qov->stack, e, node);
> +}
> +
> +static void *qapi_dealloc_pop(QapiDeallocVisitor *qov)
> +{
> +    StackEntry *e = QTAILQ_FIRST(&qov->stack);
> +    QObject *value;
> +    QTAILQ_REMOVE(&qov->stack, e, node);
> +    value = e->value;
> +    qemu_free(e);
> +    return value;
> +}
> +
> +static void qapi_dealloc_start_struct(Visitor *v, void **obj, const char *kind, const char *name, size_t unused, Error **errp)
> +{
> +    QapiDeallocVisitor *qov = to_qov(v);
> +    qapi_dealloc_push(qov, obj);
> +}
> +
> +static void qapi_dealloc_end_struct(Visitor *v, Error **errp)
> +{
> +    QapiDeallocVisitor *qov = to_qov(v);
> +    void **obj = qapi_dealloc_pop(qov);
> +    if (obj && *obj) {
> +        qemu_free(*obj);
> +    }
> +}
> +
> +static void qapi_dealloc_start_list(Visitor *v, const char *name, Error **errp)
> +{
> +}
> +
> +static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **list, Error **errp)
> +{
> +    GenericList *retval = *list;
> +    if (retval->value) {
> +        qemu_free(retval->value);
> +    }
> +    *list = retval->next;
> +    return retval;
> +}
> +
> +static void qapi_dealloc_end_list(Visitor *v, Error **errp)
> +{
> +}
> +
> +static void qapi_dealloc_type_str(Visitor *v, char **obj, const char *name, Error **errp)
> +{
> +    if (obj && *obj) {
> +        qemu_free(*obj);
> +    }

qemu_free() knows how to deal with nulls. This applies to the three
qemu_free() calls in above.

> +}
> +
> +static void qapi_dealloc_type_int(Visitor *v, int64_t *obj, const char *name, Error **errp)
> +{
> +}
> +
> +static void qapi_dealloc_type_bool(Visitor *v, bool *obj, const char *name, Error **errp)
> +{
> +}
> +
> +static void qapi_dealloc_type_number(Visitor *v, double *obj, const char *name, Error **errp)
> +{
> +}
> +
> +static void qapi_dealloc_type_enum(Visitor *v, int *obj, const char *kind, const char *name, Error **errp)
> +{
> +}
> +
> +Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v)
> +{
> +    return &v->visitor;
> +}
> +
> +void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *v)
> +{
> +    qemu_free(v);
> +}
> +
> +QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
> +{
> +    QapiDeallocVisitor *v;
> +
> +    v = qemu_mallocz(sizeof(*v));
> +
> +    v->visitor.start_struct = qapi_dealloc_start_struct;
> +    v->visitor.end_struct = qapi_dealloc_end_struct;
> +    v->visitor.start_list = qapi_dealloc_start_list;
> +    v->visitor.next_list = qapi_dealloc_next_list;
> +    v->visitor.end_list = qapi_dealloc_end_list;
> +    v->visitor.type_enum = qapi_dealloc_type_enum;
> +    v->visitor.type_int = qapi_dealloc_type_int;
> +    v->visitor.type_bool = qapi_dealloc_type_bool;
> +    v->visitor.type_str = qapi_dealloc_type_str;
> +    v->visitor.type_number = qapi_dealloc_type_number;
> +
> +    QTAILQ_INIT(&v->stack);
> +
> +    return v;
> +}
> diff --git a/qapi/qapi-dealloc-visitor.h b/qapi/qapi-dealloc-visitor.h
> new file mode 100644
> index 0000000..5842bc7
> --- /dev/null
> +++ b/qapi/qapi-dealloc-visitor.h
> @@ -0,0 +1,26 @@
> +/*
> + * Dealloc Visitor
> + *
> + * Copyright IBM, Corp. 2011
> + *
> + * Authors:
> + *  Michael Roth   <mdroth@linux.vnet.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.
> + *
> + */
> +
> +#ifndef QAPI_DEALLOC_VISITOR_H
> +#define QAPI_DEALLOC_VISITOR_H
> +
> +#include "qapi-visit-core.h"
> +
> +typedef struct QapiDeallocVisitor QapiDeallocVisitor;
> +
> +QapiDeallocVisitor *qapi_dealloc_visitor_new(void);
> +void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *d);
> +
> +Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v);
> +
> +#endif