Patchwork [v1,13/23] qapi: add QMP input visiter

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Submitter Michael Roth
Date May 18, 2011, 12:52 a.m.
Message ID <1305679930-4215-14-git-send-email-mdroth@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/96106/
State New
Headers show

Comments

Michael Roth - May 18, 2011, 12:52 a.m.
A type of Visiter class that is used to walk a qobject's
structure and assign each entry to the corresponding native C type.
Command marshaling function will use this to pull out QMP command
parameters recieved over the wire and pass them as native arguments
to the corresponding C functions.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 qapi/qmp-input-visiter.c |  239 ++++++++++++++++++++++++++++++++++++++++++++++
 qapi/qmp-input-visiter.h |   13 +++
 2 files changed, 252 insertions(+), 0 deletions(-)
 create mode 100644 qapi/qmp-input-visiter.c
 create mode 100644 qapi/qmp-input-visiter.h
Stefan Hajnoczi - May 18, 2011, 8:35 a.m.
On Wed, May 18, 2011 at 1:52 AM, Michael Roth <mdroth@linux.vnet.ibm.com> wrote:
> A type of Visiter class that is used to walk a qobject's
> structure and assign each entry to the corresponding native C type.
> Command marshaling function will use this to pull out QMP command
> parameters recieved over the wire and pass them as native arguments
> to the corresponding C functions.
>
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> ---
>  qapi/qmp-input-visiter.c |  239 ++++++++++++++++++++++++++++++++++++++++++++++
>  qapi/qmp-input-visiter.h |   13 +++
>  2 files changed, 252 insertions(+), 0 deletions(-)
>  create mode 100644 qapi/qmp-input-visiter.c
>  create mode 100644 qapi/qmp-input-visiter.h

Pedantic note: the design pattern is commonly spelled "visitor":
http://en.wikipedia.org/wiki/Visitor_pattern

The fixed-size stack and hardcoded object size are unfortunate but I
haven't read the code in enough detail to see if there is a feasible
alternative.

Stefan

Patch

diff --git a/qapi/qmp-input-visiter.c b/qapi/qmp-input-visiter.c
new file mode 100644
index 0000000..6767e39
--- /dev/null
+++ b/qapi/qmp-input-visiter.c
@@ -0,0 +1,239 @@ 
+#include "qmp-input-visiter.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+#include "qemu-objects.h"
+#include "qerror.h"
+
+#define QAPI_OBJECT_SIZE 512
+
+#define QIV_STACK_SIZE 1024
+
+typedef struct StackObject
+{
+    QObject *obj;
+    QListEntry *entry;
+} StackObject;
+
+struct QmpInputVisiter
+{
+    Visiter visiter;
+    QObject *obj;
+    StackObject stack[QIV_STACK_SIZE];
+    int nb_stack;
+};
+
+static QmpInputVisiter *to_qiv(Visiter *v)
+{
+    return container_of(v, QmpInputVisiter, visiter);
+}
+
+static QObject *qmp_input_get_object(QmpInputVisiter *qiv, const char *name)
+{
+    QObject *qobj;
+
+    if (qiv->nb_stack == 0) {
+        qobj = qiv->obj;
+    } else {
+        qobj = qiv->stack[qiv->nb_stack - 1].obj;
+    }
+
+    if (name && qobject_type(qobj) == QTYPE_QDICT) {
+        return qdict_get(qobject_to_qdict(qobj), name);
+    } else if (qiv->nb_stack > 0 && qobject_type(qobj) == QTYPE_QLIST) {
+        return qlist_entry_obj(qiv->stack[qiv->nb_stack - 1].entry);
+    }
+
+    return qobj;
+}
+
+static void qmp_input_push(QmpInputVisiter *qiv, QObject *obj)
+{
+    qiv->stack[qiv->nb_stack].obj = obj;
+    if (qobject_type(obj) == QTYPE_QLIST) {
+        qiv->stack[qiv->nb_stack].entry = qlist_first(qobject_to_qlist(obj));
+    }
+    qiv->nb_stack++;
+
+    assert(qiv->nb_stack < QIV_STACK_SIZE); // FIXME
+}
+
+static void qmp_input_pop(QmpInputVisiter *qiv)
+{
+    qiv->nb_stack--;
+    assert(qiv->nb_stack >= 0); // FIXME
+}
+
+static void qmp_input_start_struct(Visiter *v, void **obj, const char *kind, const char *name, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QDICT) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "object");
+        return;
+    }
+
+    qmp_input_push(qiv, qobj);
+
+    if (obj) {
+        *obj = qemu_mallocz(QAPI_OBJECT_SIZE);
+    }
+}
+
+static void qmp_input_end_struct(Visiter *v, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+
+    qmp_input_pop(qiv);
+}
+
+static void qmp_input_start_list(Visiter *v, const char *name, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QLIST) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "list");
+        return;
+    }
+
+    qmp_input_push(qiv, qobj);
+}
+
+static GenericList *qmp_input_next_list(Visiter *v, GenericList **list, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+    GenericList *entry;
+    StackObject *so = &qiv->stack[qiv->nb_stack - 1];
+
+    if (so->entry == NULL) {
+        return NULL;
+    }
+
+    entry = qemu_mallocz(sizeof(*entry));
+    if (*list) {
+        so->entry = qlist_next(so->entry);
+        if (so->entry == NULL) {
+            qemu_free(entry);
+            return NULL;
+        }
+        (*list)->next = entry;
+    }
+    *list = entry;
+
+    
+    return entry;
+}
+
+static void qmp_input_end_list(Visiter *v, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+
+    qmp_input_pop(qiv);
+}
+
+static void qmp_input_type_int(Visiter *v, int64_t *obj, const char *name, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QINT) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "integer");
+        return;
+    }
+
+    *obj = qint_get_int(qobject_to_qint(qobj));
+}
+
+static void qmp_input_type_bool(Visiter *v, bool *obj, const char *name, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QBOOL) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");
+        return;
+    }
+
+    *obj = qbool_get_int(qobject_to_qbool(qobj));
+}
+
+static void qmp_input_type_str(Visiter *v, char **obj, const char *name, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QSTRING) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");
+        return;
+    }
+
+    *obj = qemu_strdup(qstring_get_str(qobject_to_qstring(qobj)));
+}
+
+static void qmp_input_type_number(Visiter *v, double *obj, const char *name, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QFLOAT) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "double");
+        return;
+    }
+
+    *obj = qfloat_get_double(qobject_to_qfloat(qobj));
+}
+
+static void qmp_input_type_enum(Visiter *v, int *obj, const char *kind, const char *name, Error **errp)
+{
+    int64_t value;
+    qmp_input_type_int(v, &value, name, errp);
+    *obj = value;
+}
+
+static void qmp_input_start_optional(Visiter *v, bool *present,
+                                     const char *name, Error **errp)
+{
+    QmpInputVisiter *qiv = to_qiv(v);
+    QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj) {
+        *present = false;
+        return;
+    }
+
+    *present = true;
+}
+
+static void qmp_input_end_optional(Visiter *v, Error **errp)
+{
+}
+
+Visiter *qmp_input_get_visiter(QmpInputVisiter *v)
+{
+    return &v->visiter;
+}
+
+QmpInputVisiter *qmp_input_visiter_new(QObject *obj)
+{
+    QmpInputVisiter *v;
+
+    v = qemu_mallocz(sizeof(*v));
+
+    v->visiter.start_struct = qmp_input_start_struct;
+    v->visiter.end_struct = qmp_input_end_struct;
+    v->visiter.start_list = qmp_input_start_list;
+    v->visiter.next_list = qmp_input_next_list;
+    v->visiter.end_list = qmp_input_end_list;
+    v->visiter.type_enum = qmp_input_type_enum;
+    v->visiter.type_int = qmp_input_type_int;
+    v->visiter.type_bool = qmp_input_type_bool;
+    v->visiter.type_str = qmp_input_type_str;
+    v->visiter.type_number = qmp_input_type_number;
+    v->visiter.start_optional = qmp_input_start_optional;
+    v->visiter.end_optional = qmp_input_end_optional;
+
+    v->obj = obj;
+
+    return v;
+}
diff --git a/qapi/qmp-input-visiter.h b/qapi/qmp-input-visiter.h
new file mode 100644
index 0000000..71eb380
--- /dev/null
+++ b/qapi/qmp-input-visiter.h
@@ -0,0 +1,13 @@ 
+#ifndef QMP_INPUT_VISITER_H
+#define QMP_INPUT_VISITER_H
+
+#include "qapi-visit-core.h"
+#include "qobject.h"
+
+typedef struct QmpInputVisiter QmpInputVisiter;
+
+QmpInputVisiter *qmp_input_visiter_new(QObject *obj);
+
+Visiter *qmp_input_get_visiter(QmpInputVisiter *v);
+
+#endif