qapi: add QMP input visitor

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>
Signed-off-by: Luiz Capitulino <lcapitulino@gmail.com>

Makefile.objs

@@ -375,7 +375,7 @@ 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
+qapi-nested-y = qapi-visit-core.o qmp-input-visitor.o
 qapi-obj-y = $(addprefix qapi/, $(qapi-nested-y))
 
 vl.o: QEMU_CFLAGS+=$(GPROF_CFLAGS)

qapi/qmp-input-visitor.c

@@ -0,0 +1,301 @@
+/*
+ * Input Visitor
+ *
+ * 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 "qmp-input-visitor.h"
+#include "qemu-queue.h"
+#include "qemu-common.h"
+#include "qemu-objects.h"
+#include "qerror.h"
+
+#define QIV_STACK_SIZE 1024
+
+typedef struct StackObject
+{
+    const QObject *obj;
+    const  QListEntry *entry;
+} StackObject;
+
+struct QmpInputVisitor
+{
+    Visitor visitor;
+    QObject *obj;
+    StackObject stack[QIV_STACK_SIZE];
+    int nb_stack;
+};
+
+static QmpInputVisitor *to_qiv(Visitor *v)
+{
+    return container_of(v, QmpInputVisitor, visitor);
+}
+
+static const QObject *qmp_input_get_object(QmpInputVisitor *qiv,
+                                           const char *name)
+{
+    const 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(QmpInputVisitor *qiv, const QObject *obj, Error **errp)
+{
+    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++;
+
+    if (qiv->nb_stack >= QIV_STACK_SIZE) {
+        error_set(errp, QERR_BUFFER_OVERRUN);
+        return;
+    }
+}
+
+static void qmp_input_pop(QmpInputVisitor *qiv, Error **errp)
+{
+    qiv->nb_stack--;
+    if (qiv->nb_stack < 0) {
+        error_set(errp, QERR_BUFFER_OVERRUN);
+        return;
+    }
+}
+
+static void qmp_input_start_struct(Visitor *v, void **obj, const char *kind,
+                                   const char *name, size_t size, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    const QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QDICT) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "QDict");
+        return;
+    }
+
+    qmp_input_push(qiv, qobj, errp);
+    if (error_is_set(errp)) {
+        return;
+    }
+
+    if (obj) {
+        *obj = qemu_mallocz(size);
+    }
+}
+
+static void qmp_input_end_struct(Visitor *v, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+
+    qmp_input_pop(qiv, errp);
+}
+
+static void qmp_input_start_list(Visitor *v, const char *name, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    const QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QLIST) {
+        error_set(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,
+                                        Error **errp)
+{
+    QmpInputVisitor *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(Visitor *v, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+
+    qmp_input_pop(qiv, errp);
+}
+
+static void qmp_input_type_int(Visitor *v, int64_t *obj, const char *name,
+                               Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    const QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QINT) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "integer");
+        return;
+    }
+
+    *obj = qint_get_int(qobject_to_qint(qobj));
+}
+
+static void qmp_input_type_bool(Visitor *v, bool *obj, const char *name,
+                                Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    const QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QBOOL) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "boolean");
+        return;
+    }
+
+    *obj = qbool_get_int(qobject_to_qbool(qobj));
+}
+
+static void qmp_input_type_str(Visitor *v, char **obj, const char *name,
+                               Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    const QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QSTRING) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "string");
+        return;
+    }
+
+    *obj = qemu_strdup(qstring_get_str(qobject_to_qstring(qobj)));
+}
+
+static void qmp_input_type_number(Visitor *v, double *obj, const char *name,
+                                  Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    const QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj || qobject_type(qobj) != QTYPE_QFLOAT) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "double");
+        return;
+    }
+
+    *obj = qfloat_get_double(qobject_to_qfloat(qobj));
+}
+
+static void qmp_input_type_enum(Visitor *v, int *obj, const char *strings[],
+                                const char *kind, const char *name,
+                                Error **errp)
+{
+    int64_t value = 0;
+    char *enum_str;
+
+    assert(strings);
+
+    qmp_input_type_str(v, &enum_str, name, errp);
+    if (error_is_set(errp)) {
+        return;
+    }
+
+    while (strings[value] != NULL) {
+        if (strcmp(strings[value], enum_str) == 0) {
+            break;
+        }
+        value++;
+    }
+
+    if (strings[value] == NULL) {
+        error_set(errp, QERR_INVALID_PARAMETER, name ? name : "null");
+        return;
+    }
+
+    *obj = value;
+}
+
+static void qmp_input_start_optional(Visitor *v, bool *present,
+                                     const char *name, Error **errp)
+{
+    QmpInputVisitor *qiv = to_qiv(v);
+    const QObject *qobj = qmp_input_get_object(qiv, name);
+
+    if (!qobj) {
+        *present = false;
+        return;
+    }
+
+    *present = true;
+}
+
+static void qmp_input_end_optional(Visitor *v, Error **errp)
+{
+}
+
+Visitor *qmp_input_get_visitor(QmpInputVisitor *v)
+{
+    return &v->visitor;
+}
+
+void qmp_input_visitor_cleanup(QmpInputVisitor *v)
+{
+    qobject_decref(v->obj);
+    qemu_free(v);
+}
+
+QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
+{
+    QmpInputVisitor *v;
+
+    v = qemu_mallocz(sizeof(*v));
+
+    v->visitor.start_struct = qmp_input_start_struct;
+    v->visitor.end_struct = qmp_input_end_struct;
+    v->visitor.start_list = qmp_input_start_list;
+    v->visitor.next_list = qmp_input_next_list;
+    v->visitor.end_list = qmp_input_end_list;
+    v->visitor.type_enum = qmp_input_type_enum;
+    v->visitor.type_int = qmp_input_type_int;
+    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.start_optional = qmp_input_start_optional;
+    v->visitor.end_optional = qmp_input_end_optional;
+
+    v->obj = obj;
+    qobject_incref(v->obj);
+
+    return v;
+}

qapi/qmp-input-visitor.h

@@ -0,0 +1,27 @@
+/*
+ * Input Visitor
+ *
+ * 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.
+ *
+ */
+
+#ifndef QMP_INPUT_VISITOR_H
+#define QMP_INPUT_VISITOR_H
+
+#include "qapi-visit-core.h"
+#include "qobject.h"
+
+typedef struct QmpInputVisitor QmpInputVisitor;
+
+QmpInputVisitor *qmp_input_visitor_new(QObject *obj);
+void qmp_input_visitor_cleanup(QmpInputVisitor *v);
+
+Visitor *qmp_input_get_visitor(QmpInputVisitor *v);
+
+#endif

qerror.h

@@ -124,6 +124,9 @@ QError *qobject_to_qerror(const QObject *obj);
 #define QERR_JSON_PARSE_ERROR \
     "{ 'class': 'JSONParseError', 'data': { 'message': %s } }"
 
+#define QERR_BUFFER_OVERRUN \
+    "{ 'class': 'BufferOverrun', 'data': {} }"
+
 #define QERR_KVM_MISSING_CAP \
     "{ 'class': 'KVMMissingCap', 'data': { 'capability': %s, 'feature': %s } }"