Re: [Qemu-devel] [PATCH v2 01/15] qom: add helpers for UserCreatable object types

[Daniel P. Berrange]

Copying Andreas into the qom: related patch in this series

On Mon, Jan 11, 2016 at 03:00:45PM +0000, Daniel P. Berrange wrote:
> The QMP monitor code has two helper methods object_add
> and qmp_object_del that are called from several places
> in the code (QMP, HMP and main emulator startup).
> 
> The HMP and main emulator startup code also share
> further logic that extracts the qom-type & id
> values from a qdict.
> 
> We soon need to use this logic from qemu-img, qemu-io
> and qemu-nbd too, but don't want those to depend on
> the monitor, nor do we want to duplicate the code.
> 
> To avoid this, move some code out of qmp.c and hmp.c
> adding 3 new methods to qom/object_interfaces.c
> 
>  - user_creatable_add - takes a QDict holding a full
>    object definition & instantiates it
>  - user_creatable_add_type - takes an ID, type name,
>    and QDict holding object properties & instantiates
>    it
>  - user_creatable_del - takes an ID and deletes the
>    corresponding object
> 
> The existing code is updated to use these new methods.
> 
> Signed-off-by: Daniel P. Berrange <address@hidden>
> ---
>  hmp.c                           |  52 ++++-----------
>  include/monitor/monitor.h       |   3 -
>  include/qom/object_interfaces.h |  48 ++++++++++++++
>  qmp.c                           |  76 ++--------------------
>  qom/object_interfaces.c         | 139 
> ++++++++++++++++++++++++++++++++++++++++
>  vl.c                            |  48 ++++----------
>  6 files changed, 216 insertions(+), 150 deletions(-)
> 
> diff --git a/hmp.c b/hmp.c
> index c2b2c16..6a9c51d 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -29,6 +29,7 @@
>  #include "qapi/string-output-visitor.h"
>  #include "qapi/util.h"
>  #include "qapi-visit.h"
> +#include "qom/object_interfaces.h"
>  #include "ui/console.h"
>  #include "block/qapi.h"
>  #include "qemu-io.h"
> @@ -1663,58 +1664,27 @@ void hmp_netdev_del(Monitor *mon, const QDict *qdict)
>  void hmp_object_add(Monitor *mon, const QDict *qdict)
>  {
>      Error *err = NULL;
> -    Error *err_end = NULL;
>      QemuOpts *opts;
> -    char *type = NULL;
> -    char *id = NULL;
> -    void *dummy = NULL;
>      OptsVisitor *ov;
> -    QDict *pdict;
> +    Object *obj = NULL;
>  
>      opts = qemu_opts_from_qdict(qemu_find_opts("object"), qdict, &err);
>      if (err) {
> -        goto out;
> +        hmp_handle_error(mon, &err);
> +        return;
>      }
>  
>      ov = opts_visitor_new(opts);
> -    pdict = qdict_clone_shallow(qdict);
> -
> -    visit_start_struct(opts_get_visitor(ov), &dummy, NULL, NULL, 0, &err);
> -    if (err) {
> -        goto out_clean;
> -    }
> -
> -    qdict_del(pdict, "qom-type");
> -    visit_type_str(opts_get_visitor(ov), &type, "qom-type", &err);
> -    if (err) {
> -        goto out_end;
> -    }
> +    obj = user_creatable_add(qdict, opts_get_visitor(ov), &err);
> +    opts_visitor_cleanup(ov);
> +    qemu_opts_del(opts);
>  
> -    qdict_del(pdict, "id");
> -    visit_type_str(opts_get_visitor(ov), &id, "id", &err);
>      if (err) {
> -        goto out_end;
> +        hmp_handle_error(mon, &err);
>      }
> -
> -    object_add(type, id, pdict, opts_get_visitor(ov), &err);
> -
> -out_end:
> -    visit_end_struct(opts_get_visitor(ov), &err_end);
> -    if (!err && err_end) {
> -        qmp_object_del(id, NULL);
> +    if (obj) {
> +        object_unref(obj);
>      }
> -    error_propagate(&err, err_end);
> -out_clean:
> -    opts_visitor_cleanup(ov);
> -
> -    QDECREF(pdict);
> -    qemu_opts_del(opts);
> -    g_free(id);
> -    g_free(type);
> -    g_free(dummy);
> -
> -out:
> -    hmp_handle_error(mon, &err);
>  }
>  
>  void hmp_getfd(Monitor *mon, const QDict *qdict)
> @@ -1944,7 +1914,7 @@ void hmp_object_del(Monitor *mon, const QDict *qdict)
>      const char *id = qdict_get_str(qdict, "id");
>      Error *err = NULL;
>  
> -    qmp_object_del(id, &err);
> +    user_creatable_del(id, &err);
>      hmp_handle_error(mon, &err);
>  }
>  
> diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h
> index 91b95ae..aa0f373 100644
> --- a/include/monitor/monitor.h
> +++ b/include/monitor/monitor.h
> @@ -43,9 +43,6 @@ void monitor_read_command(Monitor *mon, int show_prompt);
>  int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
>                            void *opaque);
>  
> -void object_add(const char *type, const char *id, const QDict *qdict,
> -                Visitor *v, Error **errp);
> -
>  AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdset_id, int64_t fdset_id,
>                                  bool has_opaque, const char *opaque,
>                                  Error **errp);
> diff --git a/include/qom/object_interfaces.h b/include/qom/object_interfaces.h
> index 283ae0d..7bbaf2f 100644
> --- a/include/qom/object_interfaces.h
> +++ b/include/qom/object_interfaces.h
> @@ -2,6 +2,8 @@
>  #define OBJECT_INTERFACES_H
>  
>  #include "qom/object.h"
> +#include "qapi/qmp/qdict.h"
> +#include "qapi/visitor.h"
>  
>  #define TYPE_USER_CREATABLE "user-creatable"
>  
> @@ -72,4 +74,50 @@ void user_creatable_complete(Object *obj, Error **errp);
>   * from implements USER_CREATABLE interface.
>   */
>  bool user_creatable_can_be_deleted(UserCreatable *uc, Error **errp);
> +
> +/**
> + * user_creatable_add:
> + * @qdict: the object definition
> + * @v: the visitor
> + * @errp: if an error occurs, a pointer to an area to store the error
> + *
> + * Create an instance of the user creatable object whose type,
> + * is defined in @qdict by the 'qom-type' field, placing it
> + * in the object composition tree with name provided by the
> + * 'id' field. The remaining fields in @qdict are used to
> + * initialize the object properties.
> + *
> + * Returns: the newly created object or NULL on error
> + */
> +Object *user_creatable_add(const QDict *qdict,
> +                           Visitor *v, Error **errp);
> +
> +/**
> + * user_creatable_add_type:
> + * @type: the object type name
> + * @id: the unique ID for the object
> + * @qdict: the object properties
> + * @v: the visitor
> + * @errp: if an error occurs, a pointer to an area to store the error
> + *
> + * Create an instance of the user creatable object @type, placing
> + * it in the object composition tree with name @id, initializing
> + * it with properties from @qdict
> + *
> + * Returns: the newly created object or NULL on error
> + */
> +Object *user_creatable_add_type(const char *type, const char *id,
> +                                const QDict *qdict,
> +                                Visitor *v, Error **errp);
> +
> +/**
> + * user_creatable_del:
> + * @id: the unique ID for the object
> + * @errp: if an error occurs, a pointer to an area to store the error
> + *
> + * Delete an instance of the user creatable object identified
> + * by @id.
> + */
> +void user_creatable_del(const char *id, Error **errp);
> +
>  #endif
> diff --git a/qmp.c b/qmp.c
> index 0a1fa19..15fee9b 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -622,65 +622,13 @@ void qmp_add_client(const char *protocol, const char 
> *fdname,
>      close(fd);
>  }
>  
> -void object_add(const char *type, const char *id, const QDict *qdict,
> -                Visitor *v, Error **errp)
> -{
> -    Object *obj;
> -    ObjectClass *klass;
> -    const QDictEntry *e;
> -    Error *local_err = NULL;
> -
> -    klass = object_class_by_name(type);
> -    if (!klass) {
> -        error_setg(errp, "invalid object type: %s", type);
> -        return;
> -    }
> -
> -    if (!object_class_dynamic_cast(klass, TYPE_USER_CREATABLE)) {
> -        error_setg(errp, "object type '%s' isn't supported by object-add",
> -                   type);
> -        return;
> -    }
> -
> -    if (object_class_is_abstract(klass)) {
> -        error_setg(errp, "object type '%s' is abstract", type);
> -        return;
> -    }
> -
> -    obj = object_new(type);
> -    if (qdict) {
> -        for (e = qdict_first(qdict); e; e = qdict_next(qdict, e)) {
> -            object_property_set(obj, v, e->key, &local_err);
> -            if (local_err) {
> -                goto out;
> -            }
> -        }
> -    }
> -
> -    object_property_add_child(object_get_objects_root(),
> -                              id, obj, &local_err);
> -    if (local_err) {
> -        goto out;
> -    }
> -
> -    user_creatable_complete(obj, &local_err);
> -    if (local_err) {
> -        object_property_del(object_get_objects_root(),
> -                            id, &error_abort);
> -        goto out;
> -    }
> -out:
> -    if (local_err) {
> -        error_propagate(errp, local_err);
> -    }
> -    object_unref(obj);
> -}
>  
>  void qmp_object_add(const char *type, const char *id,
>                      bool has_props, QObject *props, Error **errp)
>  {
>      const QDict *pdict = NULL;
>      QmpInputVisitor *qiv;
> +    Object *obj;
>  
>      if (props) {
>          pdict = qobject_to_qdict(props);
> @@ -691,27 +639,17 @@ void qmp_object_add(const char *type, const char *id,
>      }
>  
>      qiv = qmp_input_visitor_new(props);
> -    object_add(type, id, pdict, qmp_input_get_visitor(qiv), errp);
> +    obj = user_creatable_add_type(type, id, pdict,
> +                                  qmp_input_get_visitor(qiv), errp);
>      qmp_input_visitor_cleanup(qiv);
> +    if (obj) {
> +        object_unref(obj);
> +    }
>  }
>  
>  void qmp_object_del(const char *id, Error **errp)
>  {
> -    Object *container;
> -    Object *obj;
> -
> -    container = object_get_objects_root();
> -    obj = object_resolve_path_component(container, id);
> -    if (!obj) {
> -        error_setg(errp, "object id not found");
> -        return;
> -    }
> -
> -    if (!user_creatable_can_be_deleted(USER_CREATABLE(obj), errp)) {
> -        error_setg(errp, "%s is in use, can not be deleted", id);
> -        return;
> -    }
> -    object_unparent(obj);
> +    user_creatable_del(id, errp);
>  }
>  
>  MemoryDeviceInfoList *qmp_query_memory_devices(Error **errp)
> diff --git a/qom/object_interfaces.c b/qom/object_interfaces.c
> index a66cd60..9c15db3 100644
> --- a/qom/object_interfaces.c
> +++ b/qom/object_interfaces.c
> @@ -30,6 +30,145 @@ bool user_creatable_can_be_deleted(UserCreatable *uc, 
> Error **errp)
>      }
>  }
>  
> +
> +Object *user_creatable_add(const QDict *qdict,
> +                           Visitor *v, Error **errp)
> +{
> +    char *type = NULL;
> +    char *id = NULL;
> +    Object *obj = NULL;
> +    Error *local_err = NULL, *end_err = NULL;
> +    QDict *pdict;
> +
> +    pdict = qdict_clone_shallow(qdict);
> +
> +    visit_start_struct(v, NULL, NULL, NULL, 0, &local_err);
> +    if (local_err) {
> +        goto out;
> +    }
> +
> +    qdict_del(pdict, "qom-type");
> +    visit_type_str(v, &type, "qom-type", &local_err);
> +    if (local_err) {
> +        goto out_visit;
> +    }
> +
> +    qdict_del(pdict, "id");
> +    visit_type_str(v, &id, "id", &local_err);
> +    if (local_err) {
> +        goto out_visit;
> +    }
> +
> +    obj = user_creatable_add_type(type, id, pdict, v, &local_err);
> +    if (local_err) {
> +        goto out_visit;
> +    }
> +
> + out_visit:
> +    visit_end_struct(v, &end_err);
> +    if (end_err) {
> +        if (!local_err) {
> +            error_propagate(&local_err, end_err);
> +        } else {
> +            error_free(end_err);
> +        }
> +        if (obj) {
> +            user_creatable_del(id, NULL);
> +        }
> +        goto out;
> +    }
> +
> +out:
> +    QDECREF(pdict);
> +    g_free(id);
> +    g_free(type);
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        if (obj) {
> +            object_unref(obj);
> +        }
> +        return NULL;
> +    }
> +    return obj;
> +}
> +
> +
> +Object *user_creatable_add_type(const char *type, const char *id,
> +                                const QDict *qdict,
> +                                Visitor *v, Error **errp)
> +{
> +    Object *obj;
> +    ObjectClass *klass;
> +    const QDictEntry *e;
> +    Error *local_err = NULL;
> +
> +    klass = object_class_by_name(type);
> +    if (!klass) {
> +        error_setg(errp, "invalid object type: %s", type);
> +        return NULL;
> +    }
> +
> +    if (!object_class_dynamic_cast(klass, TYPE_USER_CREATABLE)) {
> +        error_setg(errp, "object type '%s' isn't supported by object-add",
> +                   type);
> +        return NULL;
> +    }
> +
> +    if (object_class_is_abstract(klass)) {
> +        error_setg(errp, "object type '%s' is abstract", type);
> +        return NULL;
> +    }
> +
> +    obj = object_new(type);
> +    if (qdict) {
> +        for (e = qdict_first(qdict); e; e = qdict_next(qdict, e)) {
> +            object_property_set(obj, v, e->key, &local_err);
> +            if (local_err) {
> +                goto out;
> +            }
> +        }
> +    }
> +
> +    object_property_add_child(object_get_objects_root(),
> +                              id, obj, &local_err);
> +    if (local_err) {
> +        goto out;
> +    }
> +
> +    user_creatable_complete(obj, &local_err);
> +    if (local_err) {
> +        object_property_del(object_get_objects_root(),
> +                            id, &error_abort);
> +        goto out;
> +    }
> +out:
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        object_unref(obj);
> +        return NULL;
> +    }
> +    return obj;
> +}
> +
> +void user_creatable_del(const char *id, Error **errp)
> +{
> +    Object *container;
> +    Object *obj;
> +
> +    container = object_get_objects_root();
> +    obj = object_resolve_path_component(container, id);
> +    if (!obj) {
> +        error_setg(errp, "object id not found");
> +        return;
> +    }
> +
> +    if (!user_creatable_can_be_deleted(USER_CREATABLE(obj), errp)) {
> +        error_setg(errp, "%s is in use, can not be deleted", id);
> +        return;
> +    }
> +    object_unparent(obj);
> +}
> +
>  static void register_types(void)
>  {
>      static const TypeInfo uc_interface_info = {
> diff --git a/vl.c b/vl.c
> index 5aaea77..0287f48 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2828,52 +2828,26 @@ static bool object_create_delayed(const char *type)
>  static int object_create(void *opaque, QemuOpts *opts, Error **errp)
>  {
>      Error *err = NULL;
> -    char *type = NULL;
> -    char *id = NULL;
> -    void *dummy = NULL;
>      OptsVisitor *ov;
>      QDict *pdict;
>      bool (*type_predicate)(const char *) = opaque;
> +    Object *obj = NULL;
> +    const char *type;
>  
> -    ov = opts_visitor_new(opts);
> -    pdict = qemu_opts_to_qdict(opts, NULL);
> -
> -    visit_start_struct(opts_get_visitor(ov), &dummy, NULL, NULL, 0, &err);
> -    if (err) {
> -        goto out;
> -    }
> -
> -    qdict_del(pdict, "qom-type");
> -    visit_type_str(opts_get_visitor(ov), &type, "qom-type", &err);
> -    if (err) {
> -        goto out;
> -    }
> -    if (!type_predicate(type)) {
> -        goto out;
> -    }
> -
> -    qdict_del(pdict, "id");
> -    visit_type_str(opts_get_visitor(ov), &id, "id", &err);
> -    if (err) {
> -        goto out;
> +    type = qemu_opt_get(opts, "qom-type");
> +    if (type && !type_predicate(type)) {
> +        return 0;
>      }
>  
> -    object_add(type, id, pdict, opts_get_visitor(ov), &err);
> -    if (err) {
> -        goto out;
> -    }
> -    visit_end_struct(opts_get_visitor(ov), &err);
> -    if (err) {
> -        qmp_object_del(id, NULL);
> -    }
> +    ov = opts_visitor_new(opts);
> +    pdict = qemu_opts_to_qdict(opts, NULL);
>  
> -out:
> +    obj = user_creatable_add(pdict, opts_get_visitor(ov), &err);
>      opts_visitor_cleanup(ov);
> -
>      QDECREF(pdict);
> -    g_free(id);
> -    g_free(type);
> -    g_free(dummy);
> +    if (obj) {
> +        object_unref(obj);
> +    }
>      if (err) {
>          error_report_err(err);
>          return -1;
> -- 
> 2.5.0
> 

Regards,
Daniel
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