Merge remote-tracking branch 'bonzini/qdev-props-for-anthony' into staging

* bonzini/qdev-props-for-anthony:
  qdev: drop unnecessary parse/print methods
  qdev: use built-in QOM string parser
  qdev: accept hex properties only if prefixed by 0x
  qdev: accept both strings and integers for PCI addresses
  qom: add generic string parsing/printing
  qapi: add tests for string-based visitors
  qapi: add string-based visitors
  qapi: drop qmp_input_end_optional
  qapi: allow sharing enum implementation across visitors

16 files changed, 842 insertions, 208 deletions

diff --git a/.gitignore b/.gitignore
index f5aab2cb07..c72955aad1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -44,6 +44,8 @@ QMP/qmp-commands.txt
 test-coroutine
 test-qmp-input-visitor
 test-qmp-output-visitor
+test-string-input-visitor
+test-string-output-visitor
 fsdev/virtfs-proxy-helper.1
 fsdev/virtfs-proxy-helper.pod
 .gdbinit
diff --git a/Makefile.objs b/Makefile.objs
index 391e524525..2a4dbd1ea2 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -412,8 +412,9 @@ 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-dealloc-visitor.o
-qapi-nested-y += qmp-registry.o qmp-dispatch.o
+qapi-nested-y = qapi-visit-core.o qapi-dealloc-visitor.o qmp-input-visitor.o
+qapi-nested-y += qmp-output-visitor.o qmp-registry.o qmp-dispatch.o
+qapi-nested-y += string-input-visitor.o string-output-visitor.o
 qapi-obj-y = $(addprefix qapi/, $(qapi-nested-y))
 
 common-obj-y += qmp-marshal.o qapi-visit.o qapi-types.o $(qapi-obj-y)
diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index 7b74dd5beb..0423af1c31 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -27,16 +27,6 @@ static void bit_prop_set(DeviceState *dev, Property *props, bool val)
 }
 
 /* Bit */
-static int parse_bit(DeviceState *dev, Property *prop, const char *str)
-{
-    if (!strcasecmp(str, "on"))
-        bit_prop_set(dev, prop, true);
-    else if (!strcasecmp(str, "off"))
-        bit_prop_set(dev, prop, false);
-    else
-        return -EINVAL;
-    return 0;
-}
 
 static int print_bit(DeviceState *dev, Property *prop, char *dest, size_t len)
 {
@@ -79,7 +69,6 @@ static void set_bit(Object *obj, Visitor *v, void *opaque,
 PropertyInfo qdev_prop_bit = {
     .name  = "boolean",
     .legacy_name  = "on/off",
-    .parse = parse_bit,
     .print = print_bit,
     .get   = get_bit,
     .set   = set_bit,
@@ -87,26 +76,6 @@ PropertyInfo qdev_prop_bit = {
 
 /* --- 8bit integer --- */
 
-static int parse_uint8(DeviceState *dev, Property *prop, const char *str)
-{
-    uint8_t *ptr = qdev_get_prop_ptr(dev, prop);
-    char *end;
-
-    /* accept both hex and decimal */
-    *ptr = strtoul(str, &end, 0);
-    if ((*end != '\0') || (end == str)) {
-        return -EINVAL;
-    }
-
-    return 0;
-}
-
-static int print_uint8(DeviceState *dev, Property *prop, char *dest, size_t len)
-{
-    uint8_t *ptr = qdev_get_prop_ptr(dev, prop);
-    return snprintf(dest, len, "%" PRIu8, *ptr);
-}
-
 static void get_int8(Object *obj, Visitor *v, void *opaque,
                      const char *name, Error **errp)
 {
@@ -149,8 +118,6 @@ static void set_int8(Object *obj, Visitor *v, void *opaque,
 
 PropertyInfo qdev_prop_uint8 = {
     .name  = "uint8",
-    .parse = parse_uint8,
-    .print = print_uint8,
     .get   = get_int8,
     .set   = set_int8,
     .min   = 0,
@@ -164,6 +131,10 @@ static int parse_hex8(DeviceState *dev, Property *prop, const char *str)
     uint8_t *ptr = qdev_get_prop_ptr(dev, prop);
     char *end;
 
+    if (str[0] != '0' || str[1] != 'x') {
+        return -EINVAL;
+    }
+
     *ptr = strtoul(str, &end, 16);
     if ((*end != '\0') || (end == str)) {
         return -EINVAL;
@@ -191,26 +162,6 @@ PropertyInfo qdev_prop_hex8 = {
 
 /* --- 16bit integer --- */
 
-static int parse_uint16(DeviceState *dev, Property *prop, const char *str)
-{
-    uint16_t *ptr = qdev_get_prop_ptr(dev, prop);
-    char *end;
-
-    /* accept both hex and decimal */
-    *ptr = strtoul(str, &end, 0);
-    if ((*end != '\0') || (end == str)) {
-        return -EINVAL;
-    }
-
-    return 0;
-}
-
-static int print_uint16(DeviceState *dev, Property *prop, char *dest, size_t len)
-{
-    uint16_t *ptr = qdev_get_prop_ptr(dev, prop);
-    return snprintf(dest, len, "%" PRIu16, *ptr);
-}
-
 static void get_int16(Object *obj, Visitor *v, void *opaque,
                       const char *name, Error **errp)
 {
@@ -253,8 +204,6 @@ static void set_int16(Object *obj, Visitor *v, void *opaque,
 
 PropertyInfo qdev_prop_uint16 = {
     .name  = "uint16",
-    .parse = parse_uint16,
-    .print = print_uint16,
     .get   = get_int16,
     .set   = set_int16,
     .min   = 0,
@@ -263,26 +212,6 @@ PropertyInfo qdev_prop_uint16 = {
 
 /* --- 32bit integer --- */
 
-static int parse_uint32(DeviceState *dev, Property *prop, const char *str)
-{
-    uint32_t *ptr = qdev_get_prop_ptr(dev, prop);
-    char *end;
-
-    /* accept both hex and decimal */
-    *ptr = strtoul(str, &end, 0);
-    if ((*end != '\0') || (end == str)) {
-        return -EINVAL;
-    }
-
-    return 0;
-}
-
-static int print_uint32(DeviceState *dev, Property *prop, char *dest, size_t len)
-{
-    uint32_t *ptr = qdev_get_prop_ptr(dev, prop);
-    return snprintf(dest, len, "%" PRIu32, *ptr);
-}
-
 static void get_int32(Object *obj, Visitor *v, void *opaque,
                       const char *name, Error **errp)
 {
@@ -325,37 +254,14 @@ static void set_int32(Object *obj, Visitor *v, void *opaque,
 
 PropertyInfo qdev_prop_uint32 = {
     .name  = "uint32",
-    .parse = parse_uint32,
-    .print = print_uint32,
     .get   = get_int32,
     .set   = set_int32,
     .min   = 0,
     .max   = 0xFFFFFFFFULL,
 };
 
-static int parse_int32(DeviceState *dev, Property *prop, const char *str)
-{
-    int32_t *ptr = qdev_get_prop_ptr(dev, prop);
-    char *end;
-
-    *ptr = strtol(str, &end, 10);
-    if ((*end != '\0') || (end == str)) {
-        return -EINVAL;
-    }
-
-    return 0;
-}
-
-static int print_int32(DeviceState *dev, Property *prop, char *dest, size_t len)
-{
-    int32_t *ptr = qdev_get_prop_ptr(dev, prop);
-    return snprintf(dest, len, "%" PRId32, *ptr);
-}
-
 PropertyInfo qdev_prop_int32 = {
     .name  = "int32",
-    .parse = parse_int32,
-    .print = print_int32,
     .get   = get_int32,
     .set   = set_int32,
     .min   = -0x80000000LL,
@@ -369,6 +275,10 @@ static int parse_hex32(DeviceState *dev, Property *prop, const char *str)
     uint32_t *ptr = qdev_get_prop_ptr(dev, prop);
     char *end;
 
+    if (str[0] != '0' || str[1] != 'x') {
+        return -EINVAL;
+    }
+
     *ptr = strtoul(str, &end, 16);
     if ((*end != '\0') || (end == str)) {
         return -EINVAL;
@@ -396,26 +306,6 @@ PropertyInfo qdev_prop_hex32 = {
 
 /* --- 64bit integer --- */
 
-static int parse_uint64(DeviceState *dev, Property *prop, const char *str)
-{
-    uint64_t *ptr = qdev_get_prop_ptr(dev, prop);
-    char *end;
-
-    /* accept both hex and decimal */
-    *ptr = strtoull(str, &end, 0);
-    if ((*end != '\0') || (end == str)) {
-        return -EINVAL;
-    }
-
-    return 0;
-}
-
-static int print_uint64(DeviceState *dev, Property *prop, char *dest, size_t len)
-{
-    uint64_t *ptr = qdev_get_prop_ptr(dev, prop);
-    return snprintf(dest, len, "%" PRIu64, *ptr);
-}
-
 static void get_int64(Object *obj, Visitor *v, void *opaque,
                       const char *name, Error **errp)
 {
@@ -443,8 +333,6 @@ static void set_int64(Object *obj, Visitor *v, void *opaque,
 
 PropertyInfo qdev_prop_uint64 = {
     .name  = "uint64",
-    .parse = parse_uint64,
-    .print = print_uint64,
     .get   = get_int64,
     .set   = set_int64,
 };
@@ -456,6 +344,10 @@ static int parse_hex64(DeviceState *dev, Property *prop, const char *str)
     uint64_t *ptr = qdev_get_prop_ptr(dev, prop);
     char *end;
 
+    if (str[0] != '0' || str[1] != 'x') {
+        return -EINVAL;
+    }
+
     *ptr = strtoull(str, &end, 16);
     if ((*end != '\0') || (end == str)) {
         return -EINVAL;
@@ -737,19 +629,6 @@ PropertyInfo qdev_prop_netdev = {
 
 /* --- vlan --- */
 
-static int parse_vlan(DeviceState *dev, Property *prop, const char *str)
-{
-    VLANState **ptr = qdev_get_prop_ptr(dev, prop);
-    int id;
-
-    if (sscanf(str, "%d", &id) != 1)
-        return -EINVAL;
-    *ptr = qemu_find_vlan(id, 1);
-    if (*ptr == NULL)
-        return -ENOENT;
-    return 0;
-}
-
 static int print_vlan(DeviceState *dev, Property *prop, char *dest, size_t len)
 {
     VLANState **ptr = qdev_get_prop_ptr(dev, prop);
@@ -808,7 +687,6 @@ static void set_vlan(Object *obj, Visitor *v, void *opaque,
 
 PropertyInfo qdev_prop_vlan = {
     .name  = "vlan",
-    .parse = parse_vlan,
     .print = print_vlan,
     .get   = get_vlan,
     .set   = set_vlan,
@@ -943,25 +821,40 @@ PropertyInfo qdev_prop_losttickpolicy = {
 /*
  * bus-local address, i.e. "$slot" or "$slot.$fn"
  */
-static int parse_pci_devfn(DeviceState *dev, Property *prop, const char *str)
+static void set_pci_devfn(Object *obj, Visitor *v, void *opaque,
+                          const char *name, Error **errp)
 {
+    DeviceState *dev = DEVICE(obj);
+    Property *prop = opaque;
     uint32_t *ptr = qdev_get_prop_ptr(dev, prop);
     unsigned int slot, fn, n;
+    Error *local_err = NULL;
+    char *str = (char *)"";
+
+    if (dev->state != DEV_STATE_CREATED) {
+        error_set(errp, QERR_PERMISSION_DENIED);
+        return;
+    }
+
+    visit_type_str(v, &str, name, &local_err);
+    if (local_err) {
+        return set_int32(obj, v, opaque, name, errp);
+    }
 
     if (sscanf(str, "%x.%x%n", &slot, &fn, &n) != 2) {
         fn = 0;
         if (sscanf(str, "%x%n", &slot, &n) != 1) {
-            return -EINVAL;
+            goto invalid;
         }
     }
-    if (str[n] != '\0')
-        return -EINVAL;
-    if (fn > 7)
-        return -EINVAL;
-    if (slot > 31)
-        return -EINVAL;
+    if (str[n] != '\0' || fn > 7 || slot > 31) {
+        goto invalid;
+    }
     *ptr = slot << 3 | fn;
-    return 0;
+    return;
+
+invalid:
+    error_set_from_qdev_prop_error(errp, EINVAL, dev, prop, str);
 }
 
 static int print_pci_devfn(DeviceState *dev, Property *prop, char *dest, size_t len)
@@ -978,10 +871,9 @@ static int print_pci_devfn(DeviceState *dev, Property *prop, char *dest, size_t
 PropertyInfo qdev_prop_pci_devfn = {
     .name  = "int32",
     .legacy_name  = "pci-devfn",
-    .parse = parse_pci_devfn,
     .print = print_pci_devfn,
     .get   = get_int32,
-    .set   = set_int32,
+    .set   = set_pci_devfn,
     /* FIXME: this should be -1...255, but the address is stored
      * into an uint32_t rather than int32_t.
      */
@@ -1054,9 +946,9 @@ int qdev_prop_parse(DeviceState *dev, const char *name, const char *value)
 
     legacy_name = g_strdup_printf("legacy-%s", name);
     if (object_property_get_type(OBJECT(dev), legacy_name, NULL)) {
-        object_property_set_str(OBJECT(dev), value, legacy_name, &err);
+        object_property_parse(OBJECT(dev), value, legacy_name, &err);
     } else {
-        object_property_set_str(OBJECT(dev), value, name, &err);
+        object_property_parse(OBJECT(dev), value, name, &err);
     }
     g_free(legacy_name);
 
diff --git a/include/qemu/object.h b/include/qemu/object.h
index 5179c0cf5a..ff6be14dfc 100644
--- a/include/qemu/object.h
+++ b/include/qemu/object.h
@@ -730,6 +730,30 @@ void object_property_set(Object *obj, struct Visitor *v, const char *name,
                          struct Error **errp);
 
 /**
+ * object_property_parse:
+ * @obj: the object
+ * @string: the string that will be used to parse the property value.
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Parses a string and writes the result into a property of an object.
+ */
+void object_property_parse(Object *obj, const char *string,
+                           const char *name, struct Error **errp);
+
+/**
+ * object_property_print:
+ * @obj: the object
+ * @name: the name of the property
+ * @errp: returns an error if this function fails
+ *
+ * Returns a string representation of the value of the property.  The
+ * caller shall free the string.
+ */
+char *object_property_print(Object *obj, const char *name,
+                            struct Error **errp);
+
+/**
  * object_property_get_type:
  * @obj: the object
  * @name: the name of the property
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index ddef3eda12..a4e088c9fc 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -12,6 +12,7 @@
  */
 
 #include "qapi/qapi-visit-core.h"
+#include "qapi/qapi-visit-impl.h"
 
 void visit_start_handle(Visitor *v, void **obj, const char *kind,
                         const char *name, Error **errp)
@@ -116,3 +117,53 @@ void visit_type_number(Visitor *v, double *obj, const char *name, Error **errp)
         v->type_number(v, obj, name, errp);
     }
 }
+
+void output_type_enum(Visitor *v, int *obj, const char *strings[],
+                      const char *kind, const char *name,
+                      Error **errp)
+{
+    int i = 0;
+    int value = *obj;
+    char *enum_str;
+
+    assert(strings);
+    while (strings[i++] != NULL);
+    if (value < 0 || value >= i - 1) {
+        error_set(errp, QERR_INVALID_PARAMETER, name ? name : "null");
+        return;
+    }
+
+    enum_str = (char *)strings[value];
+    visit_type_str(v, &enum_str, name, errp);
+}
+
+void 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);
+
+    visit_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");
+        g_free(enum_str);
+        return;
+    }
+
+    g_free(enum_str);
+    *obj = value;
+}
diff --git a/qapi/qapi-visit-impl.h b/qapi/qapi-visit-impl.h
new file mode 100644
index 0000000000..0f3a1898fe
--- /dev/null
+++ b/qapi/qapi-visit-impl.h
@@ -0,0 +1,23 @@
+/*
+ * Core Definitions for QAPI Visitor implementations
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * Author: Paolo Bonizni <pbonzini@redhat.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_VISITOR_IMPL_H
+#define QAPI_VISITOR_IMPL_H
+
+#include "qapi/qapi-types-core.h"
+#include "qapi/qapi-visit-core.h"
+
+void input_type_enum(Visitor *v, int *obj, const char *strings[],
+                     const char *kind, const char *name, Error **errp);
+void output_type_enum(Visitor *v, int *obj, const char *strings[],
+                      const char *kind, const char *name, Error **errp);
+
+#endif
diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index c78022bb87..e6b6152e08 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -12,6 +12,7 @@
  */
 
 #include "qmp-input-visitor.h"
+#include "qapi/qapi-visit-impl.h"
 #include "qemu-queue.h"
 #include "qemu-common.h"
 #include "qemu-objects.h"
@@ -217,37 +218,6 @@ static void qmp_input_type_number(Visitor *v, double *obj, const char *name,
     *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");
-        g_free(enum_str);
-        return;
-    }
-
-    g_free(enum_str);
-    *obj = value;
-}
-
 static void qmp_input_start_optional(Visitor *v, bool *present,
                                      const char *name, Error **errp)
 {
@@ -262,10 +232,6 @@ static void qmp_input_start_optional(Visitor *v, bool *present,
     *present = true;
 }
 
-static void qmp_input_end_optional(Visitor *v, Error **errp)
-{
-}
-
 Visitor *qmp_input_get_visitor(QmpInputVisitor *v)
 {
     return &v->visitor;
@@ -288,13 +254,12 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj)
     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_enum = 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);
diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c
index f76d0159cd..e0697b0d0f 100644
--- a/qapi/qmp-output-visitor.c
+++ b/qapi/qmp-output-visitor.c
@@ -12,6 +12,7 @@
  */
 
 #include "qmp-output-visitor.h"
+#include "qapi/qapi-visit-impl.h"
 #include "qemu-queue.h"
 #include "qemu-common.h"
 #include "qemu-objects.h"
@@ -180,25 +181,6 @@ static void qmp_output_type_number(Visitor *v, double *obj, const char *name,
     qmp_output_add(qov, name, qfloat_from_double(*obj));
 }
 
-static void qmp_output_type_enum(Visitor *v, int *obj, const char *strings[],
-                                 const char *kind, const char *name,
-                                 Error **errp)
-{
-    int i = 0;
-    int value = *obj;
-    char *enum_str;
-
-    assert(strings);
-    while (strings[i++] != NULL);
-    if (value < 0 || value >= i - 1) {
-        error_set(errp, QERR_INVALID_PARAMETER, name ? name : "null");
-        return;
-    }
-
-    enum_str = (char *)strings[value];
-    qmp_output_type_str(v, &enum_str, name, errp);
-}
-
 QObject *qmp_output_get_qobject(QmpOutputVisitor *qov)
 {
     QObject *obj = qmp_output_first(qov);
@@ -239,7 +221,7 @@ QmpOutputVisitor *qmp_output_visitor_new(void)
     v->visitor.start_list = qmp_output_start_list;
     v->visitor.next_list = qmp_output_next_list;
     v->visitor.end_list = qmp_output_end_list;
-    v->visitor.type_enum = qmp_output_type_enum;
+    v->visitor.type_enum = output_type_enum;
     v->visitor.type_int = qmp_output_type_int;
     v->visitor.type_bool = qmp_output_type_bool;
     v->visitor.type_str = qmp_output_type_str;
diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c
new file mode 100644
index 0000000000..497eb9a60a
--- /dev/null
+++ b/qapi/string-input-visitor.c
@@ -0,0 +1,138 @@
+/*
+ * String parsing visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.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-common.h"
+#include "string-input-visitor.h"
+#include "qapi/qapi-visit-impl.h"
+#include "qerror.h"
+
+struct StringInputVisitor
+{
+    Visitor visitor;
+    const char *string;
+};
+
+static void parse_type_int(Visitor *v, int64_t *obj, const char *name,
+                           Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+    char *endp = (char *) siv->string;
+    long long val;
+
+    errno = 0;
+    if (siv->string) {
+        val = strtoll(siv->string, &endp, 0);
+    }
+    if (!siv->string || errno || endp == siv->string || *endp) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "integer");
+        return;
+    }
+
+    *obj = val;
+}
+
+static void parse_type_bool(Visitor *v, bool *obj, const char *name,
+                            Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+
+    if (siv->string) {
+        if (!strcasecmp(siv->string, "on") ||
+            !strcasecmp(siv->string, "yes") ||
+            !strcasecmp(siv->string, "true")) {
+            *obj = true;
+            return;
+        }
+        if (!strcasecmp(siv->string, "off") ||
+            !strcasecmp(siv->string, "no") ||
+            !strcasecmp(siv->string, "false")) {
+            *obj = false;
+            return;
+        }
+    }
+
+    error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+              "boolean");
+}
+
+static void parse_type_str(Visitor *v, char **obj, const char *name,
+                           Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+    if (siv->string) {
+        *obj = g_strdup(siv->string);
+    } else {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "string");
+    }
+}
+
+static void parse_type_number(Visitor *v, double *obj, const char *name,
+                              Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+    char *endp = (char *) siv->string;
+    double val;
+
+    errno = 0;
+    if (siv->string) {
+        val = strtod(siv->string, &endp);
+    }
+    if (!siv->string || errno || endp == siv->string || *endp) {
+        error_set(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+                  "number");
+        return;
+    }
+
+    *obj = val;
+}
+
+static void parse_start_optional(Visitor *v, bool *present,
+                                 const char *name, Error **errp)
+{
+    StringInputVisitor *siv = DO_UPCAST(StringInputVisitor, visitor, v);
+
+    if (!siv->string) {
+        *present = false;
+        return;
+    }
+
+    *present = true;
+}
+
+Visitor *string_input_get_visitor(StringInputVisitor *v)
+{
+    return &v->visitor;
+}
+
+void string_input_visitor_cleanup(StringInputVisitor *v)
+{
+    g_free(v);
+}
+
+StringInputVisitor *string_input_visitor_new(const char *str)
+{
+    StringInputVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.type_enum = input_type_enum;
+    v->visitor.type_int = parse_type_int;
+    v->visitor.type_bool = parse_type_bool;
+    v->visitor.type_str = parse_type_str;
+    v->visitor.type_number = parse_type_number;
+    v->visitor.start_optional = parse_start_optional;
+
+    v->string = str;
+    return v;
+}
diff --git a/qapi/string-input-visitor.h b/qapi/string-input-visitor.h
new file mode 100644
index 0000000000..d269d42cef
--- /dev/null
+++ b/qapi/string-input-visitor.h
@@ -0,0 +1,25 @@
+/*
+ * String parsing Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.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 STRING_INPUT_VISITOR_H
+#define STRING_INPUT_VISITOR_H
+
+#include "qapi-visit-core.h"
+
+typedef struct StringInputVisitor StringInputVisitor;
+
+StringInputVisitor *string_input_visitor_new(const char *str);
+void string_input_visitor_cleanup(StringInputVisitor *v);
+
+Visitor *string_input_get_visitor(StringInputVisitor *v);
+
+#endif
diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
new file mode 100644
index 0000000000..92b0305212
--- /dev/null
+++ b/qapi/string-output-visitor.c
@@ -0,0 +1,89 @@
+/*
+ * String printing Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.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-common.h"
+#include "string-output-visitor.h"
+#include "qapi/qapi-visit-impl.h"
+#include "qerror.h"
+
+struct StringOutputVisitor
+{
+    Visitor visitor;
+    char *string;
+};
+
+static void string_output_set(StringOutputVisitor *sov, char *string)
+{
+    g_free(sov->string);
+    sov->string = string;
+}
+
+static void print_type_int(Visitor *v, int64_t *obj, const char *name,
+                           Error **errp)
+{
+    StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
+    string_output_set(sov, g_strdup_printf("%lld", (long long) *obj));
+}
+
+static void print_type_bool(Visitor *v, bool *obj, const char *name,
+                            Error **errp)
+{
+    StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
+    string_output_set(sov, g_strdup(*obj ? "true" : "false"));
+}
+
+static void print_type_str(Visitor *v, char **obj, const char *name,
+                           Error **errp)
+{
+    StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
+    string_output_set(sov, g_strdup(*obj ? *obj : ""));
+}
+
+static void print_type_number(Visitor *v, double *obj, const char *name,
+                              Error **errp)
+{
+    StringOutputVisitor *sov = DO_UPCAST(StringOutputVisitor, visitor, v);
+    string_output_set(sov, g_strdup_printf("%g", *obj));
+}
+
+char *string_output_get_string(StringOutputVisitor *sov)
+{
+    char *string = sov->string;
+    sov->string = NULL;
+    return string;
+}
+
+Visitor *string_output_get_visitor(StringOutputVisitor *sov)
+{
+    return &sov->visitor;
+}
+
+void string_output_visitor_cleanup(StringOutputVisitor *sov)
+{
+    g_free(sov->string);
+    g_free(sov);
+}
+
+StringOutputVisitor *string_output_visitor_new(void)
+{
+    StringOutputVisitor *v;
+
+    v = g_malloc0(sizeof(*v));
+
+    v->visitor.type_enum = output_type_enum;
+    v->visitor.type_int = print_type_int;
+    v->visitor.type_bool = print_type_bool;
+    v->visitor.type_str = print_type_str;
+    v->visitor.type_number = print_type_number;
+
+    return v;
+}
diff --git a/qapi/string-output-visitor.h b/qapi/string-output-visitor.h
new file mode 100644
index 0000000000..8868454110
--- /dev/null
+++ b/qapi/string-output-visitor.h
@@ -0,0 +1,26 @@
+/*
+ * String printing Visitor
+ *
+ * Copyright Red Hat, Inc. 2012
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.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 STRING_OUTPUT_VISITOR_H
+#define STRING_OUTPUT_VISITOR_H
+
+#include "qapi-visit-core.h"
+
+typedef struct StringOutputVisitor StringOutputVisitor;
+
+StringOutputVisitor *string_output_visitor_new(void);
+void string_output_visitor_cleanup(StringOutputVisitor *v);
+
+char *string_output_get_string(StringOutputVisitor *v);
+Visitor *string_output_get_visitor(StringOutputVisitor *v);
+
+#endif
diff --git a/qom/object.c b/qom/object.c
index 0cbd9bb004..941c291bf9 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -13,6 +13,8 @@
 #include "qemu/object.h"
 #include "qemu-common.h"
 #include "qapi/qapi-visit-core.h"
+#include "qapi/string-input-visitor.h"
+#include "qapi/string-output-visitor.h"
 
 /* TODO: replace QObject with a simpler visitor to avoid a dependency
  * of the QOM core on QObject?  */
@@ -782,6 +784,29 @@ int64_t object_property_get_int(Object *obj, const char *name,
     return retval;
 }
 
+void object_property_parse(Object *obj, const char *string,
+                           const char *name, Error **errp)
+{
+    StringInputVisitor *mi;
+    mi = string_input_visitor_new(string);
+    object_property_set(obj, string_input_get_visitor(mi), name, errp);
+
+    string_input_visitor_cleanup(mi);
+}
+
+char *object_property_print(Object *obj, const char *name,
+                            Error **errp)
+{
+    StringOutputVisitor *mo;
+    char *string;
+
+    mo = string_output_visitor_new();
+    object_property_get(obj, string_output_get_visitor(mo), name, NULL);
+    string = string_output_get_string(mo);
+    string_output_visitor_cleanup(mo);
+    return string;
+}
+
 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
 {
     ObjectProperty *prop = object_property_find(obj, name);
diff --git a/test-string-input-visitor.c b/test-string-input-visitor.c
new file mode 100644
index 0000000000..5370e32041
--- /dev/null
+++ b/test-string-input-visitor.c
@@ -0,0 +1,195 @@
+/*
+ * String Input Visitor unit-tests.
+ *
+ * Copyright (C) 2012 Red Hat Inc.
+ *
+ * Authors:
+ *  Paolo Bonzini <pbonzini@redhat.com> (based on test-qmp-input-visitor)
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include <glib.h>
+#include <stdarg.h>
+
+#include "qapi/string-input-visitor.h"
+#include "test-qapi-types.h"
+#include "test-qapi-visit.h"
+#include "qemu-objects.h"
+
+typedef struct TestInputVisitorData {
+    StringInputVisitor *siv;
+} TestInputVisitorData;
+
+static void visitor_input_teardown(TestInputVisitorData *data,
+                                   const void *unused)
+{
+    if (data->siv) {
+        string_input_visitor_cleanup(data->siv);
+        data->siv = NULL;
+    }
+}
+
+/* This is provided instead of a test setup function so that the JSON
+   string used by the tests are kept in the test functions (and not
+   int main()) */
+static
+Visitor *visitor_input_test_init(TestInputVisitorData *data,
+                                 const char *string)
+{
+    Visitor *v;
+
+    data->siv = string_input_visitor_new(string);
+    g_assert(data->siv != NULL);
+
+    v = string_input_get_visitor(data->siv);
+    g_assert(v != NULL);
+
+    return v;
+}
+
+static void test_visitor_in_int(TestInputVisitorData *data,
+                                const void *unused)
+{
+    int64_t res = 0, value = -42;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = visitor_input_test_init(data, "-42");
+
+    visit_type_int(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpint(res, ==, value);
+}
+
+static void test_visitor_in_bool(TestInputVisitorData *data,
+                                 const void *unused)
+{
+    Error *errp = NULL;
+    bool res = false;
+    Visitor *v;
+
+    v = visitor_input_test_init(data, "true");
+
+    visit_type_bool(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpint(res, ==, true);
+    visitor_input_teardown(data, unused);
+
+    v = visitor_input_test_init(data, "yes");
+
+    visit_type_bool(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpint(res, ==, true);
+    visitor_input_teardown(data, unused);
+
+    v = visitor_input_test_init(data, "on");
+
+    visit_type_bool(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpint(res, ==, true);
+    visitor_input_teardown(data, unused);
+
+    v = visitor_input_test_init(data, "false");
+
+    visit_type_bool(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpint(res, ==, false);
+    visitor_input_teardown(data, unused);
+
+    v = visitor_input_test_init(data, "no");
+
+    visit_type_bool(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpint(res, ==, false);
+    visitor_input_teardown(data, unused);
+
+    v = visitor_input_test_init(data, "off");
+
+    visit_type_bool(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpint(res, ==, false);
+}
+
+static void test_visitor_in_number(TestInputVisitorData *data,
+                                   const void *unused)
+{
+    double res = 0, value = 3.14;
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = visitor_input_test_init(data, "3.14");
+
+    visit_type_number(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpfloat(res, ==, value);
+}
+
+static void test_visitor_in_string(TestInputVisitorData *data,
+                                   const void *unused)
+{
+    char *res = NULL, *value = (char *) "Q E M U";
+    Error *errp = NULL;
+    Visitor *v;
+
+    v = visitor_input_test_init(data, value);
+
+    visit_type_str(v, &res, NULL, &errp);
+    g_assert(!error_is_set(&errp));
+    g_assert_cmpstr(res, ==, value);
+
+    g_free(res);
+}
+
+static void test_visitor_in_enum(TestInputVisitorData *data,
+                                 const void *unused)
+{
+    Error *errp = NULL;
+    Visitor *v;
+    EnumOne i;
+
+    for (i = 0; EnumOne_lookup[i]; i++) {
+        EnumOne res = -1;
+
+        v = visitor_input_test_init(data, EnumOne_lookup[i]);
+
+        visit_type_EnumOne(v, &res, NULL, &errp);
+        g_assert(!error_is_set(&errp));
+        g_assert_cmpint(i, ==, res);
+
+        visitor_input_teardown(data, NULL);
+    }
+
+    data->siv = NULL;
+}
+
+static void input_visitor_test_add(const char *testpath,
+                                   TestInputVisitorData *data,
+                                   void (*test_func)(TestInputVisitorData *data, const void *user_data))
+{
+    g_test_add(testpath, TestInputVisitorData, data, NULL, test_func,
+               visitor_input_teardown);
+}
+
+int main(int argc, char **argv)
+{
+    TestInputVisitorData in_visitor_data;
+
+    g_test_init(&argc, &argv, NULL);
+
+    input_visitor_test_add("/string-visitor/input/int",
+                           &in_visitor_data, test_visitor_in_int);
+    input_visitor_test_add("/string-visitor/input/bool",
+                           &in_visitor_data, test_visitor_in_bool);
+    input_visitor_test_add("/string-visitor/input/number",
+                           &in_visitor_data, test_visitor_in_number);
+    input_visitor_test_add("/string-visitor/input/string",
+                            &in_visitor_data, test_visitor_in_string);
+    input_visitor_test_add("/string-visitor/input/enum",
+                            &in_visitor_data, test_visitor_in_enum);
+
+    g_test_run();
+
+    return 0;
+}
diff --git a/test-string-output-visitor.c b/test-string-output-visitor.c
new file mode 100644
index 0000000000..22909b84ef
--- /dev/null
+++ b/test-string-output-visitor.c
@@ -0,0 +1,188 @@
+/*
+ * String Output Visitor unit-tests.
+ *
+ * Copyright (C) 2012 Red Hat Inc.
+ *
+ * Authors:
+ *  Paolo Bonzini <pbonzini@redhat.com> (based on test-qmp-output-visitor)
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include <glib.h>
+
+#include "qapi/string-output-visitor.h"
+#include "test-qapi-types.h"
+#include "test-qapi-visit.h"
+#include "qemu-objects.h"
+
+typedef struct TestOutputVisitorData {
+    StringOutputVisitor *sov;
+    Visitor *ov;
+} TestOutputVisitorData;
+
+static void visitor_output_setup(TestOutputVisitorData *data,
+                                 const void *unused)
+{
+    data->sov = string_output_visitor_new();
+    g_assert(data->sov != NULL);
+
+    data->ov = string_output_get_visitor(data->sov);
+    g_assert(data->ov != NULL);
+}
+
+static void visitor_output_teardown(TestOutputVisitorData *data,
+                                    const void *unused)
+{
+    string_output_visitor_cleanup(data->sov);
+    data->sov = NULL;
+    data->ov = NULL;
+}
+
+static void test_visitor_out_int(TestOutputVisitorData *data,
+                                 const void *unused)
+{
+    int64_t value = -42;
+    Error *errp = NULL;
+    char *str;
+
+    visit_type_int(data->ov, &value, NULL, &errp);
+    g_assert(error_is_set(&errp) == 0);
+
+    str = string_output_get_string(data->sov);
+    g_assert(str != NULL);
+    g_assert_cmpstr(str, ==, "-42");
+    g_free(str);
+}
+
+static void test_visitor_out_bool(TestOutputVisitorData *data,
+                                  const void *unused)
+{
+    Error *errp = NULL;
+    bool value = true;
+    char *str;
+
+    visit_type_bool(data->ov, &value, NULL, &errp);
+    g_assert(error_is_set(&errp) == 0);
+
+    str = string_output_get_string(data->sov);
+    g_assert(str != NULL);
+    g_assert_cmpstr(str, ==, "true");
+    g_free(str);
+}
+
+static void test_visitor_out_number(TestOutputVisitorData *data,
+                                    const void *unused)
+{
+    double value = 3.14;
+    Error *errp = NULL;
+    char *str;
+
+    visit_type_number(data->ov, &value, NULL, &errp);
+    g_assert(error_is_set(&errp) == 0);
+
+    str = string_output_get_string(data->sov);
+    g_assert(str != NULL);
+    g_assert_cmpstr(str, ==, "3.14");
+    g_free(str);
+}
+
+static void test_visitor_out_string(TestOutputVisitorData *data,
+                                    const void *unused)
+{
+    char *string = (char *) "Q E M U";
+    Error *errp = NULL;
+    char *str;
+
+    visit_type_str(data->ov, &string, NULL, &errp);
+    g_assert(error_is_set(&errp) == 0);
+
+    str = string_output_get_string(data->sov);
+    g_assert(str != NULL);
+    g_assert_cmpstr(str, ==, string);
+    g_free(str);
+}
+
+static void test_visitor_out_no_string(TestOutputVisitorData *data,
+                                       const void *unused)
+{
+    char *string = NULL;
+    Error *errp = NULL;
+    char *str;
+
+    /* A null string should return "" */
+    visit_type_str(data->ov, &string, NULL, &errp);
+    g_assert(error_is_set(&errp) == 0);
+
+    str = string_output_get_string(data->sov);
+    g_assert(str != NULL);
+    g_assert_cmpstr(str, ==, "");
+    g_free(str);
+}
+
+static void test_visitor_out_enum(TestOutputVisitorData *data,
+                                  const void *unused)
+{
+    Error *errp = NULL;
+    char *str;
+    EnumOne i;
+
+    for (i = 0; i < ENUM_ONE_MAX; i++) {
+        visit_type_EnumOne(data->ov, &i, "unused", &errp);
+        g_assert(!error_is_set(&errp));
+
+        str = string_output_get_string(data->sov);
+        g_assert(str != NULL);
+        g_assert_cmpstr(str, ==, EnumOne_lookup[i]);
+	g_free(str);
+    }
+}
+
+static void test_visitor_out_enum_errors(TestOutputVisitorData *data,
+                                         const void *unused)
+{
+    EnumOne i, bad_values[] = { ENUM_ONE_MAX, -1 };
+    Error *errp;
+
+    for (i = 0; i < ARRAY_SIZE(bad_values) ; i++) {
+        errp = NULL;
+        visit_type_EnumOne(data->ov, &bad_values[i], "unused", &errp);
+        g_assert(error_is_set(&errp) == true);
+        error_free(errp);
+    }
+}
+
+static void output_visitor_test_add(const char *testpath,
+                                    TestOutputVisitorData *data,
+                                    void (*test_func)(TestOutputVisitorData *data, const void *user_data))
+{
+    g_test_add(testpath, TestOutputVisitorData, data, visitor_output_setup,
+               test_func, visitor_output_teardown);
+}
+
+int main(int argc, char **argv)
+{
+    TestOutputVisitorData out_visitor_data;
+
+    g_test_init(&argc, &argv, NULL);
+
+    output_visitor_test_add("/string-visitor/output/int",
+                            &out_visitor_data, test_visitor_out_int);
+    output_visitor_test_add("/string-visitor/output/bool",
+                            &out_visitor_data, test_visitor_out_bool);
+    output_visitor_test_add("/string-visitor/output/number",
+                            &out_visitor_data, test_visitor_out_number);
+    output_visitor_test_add("/string-visitor/output/string",
+                            &out_visitor_data, test_visitor_out_string);
+    output_visitor_test_add("/string-visitor/output/no-string",
+                            &out_visitor_data, test_visitor_out_no_string);
+    output_visitor_test_add("/string-visitor/output/enum",
+                            &out_visitor_data, test_visitor_out_enum);
+    output_visitor_test_add("/string-visitor/output/enum-errors",
+                            &out_visitor_data, test_visitor_out_enum_errors);
+
+    g_test_run();
+
+    return 0;
+}
diff --git a/tests/Makefile b/tests/Makefile
index 55e8eb0ad5..74b29dc076 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -1,6 +1,6 @@
 CHECKS = check-qdict check-qfloat check-qint check-qstring check-qlist
 CHECKS += check-qjson test-qmp-output-visitor test-qmp-input-visitor
-CHECKS += test-coroutine
+CHECKS += test-string-input-visitor test-string-output-visitor test-coroutine
 
 check-qint.o check-qstring.o check-qdict.o check-qlist.o check-qfloat.o check-qjson.o test-coroutine.o: $(GENERATED_HEADERS)
 
@@ -12,7 +12,9 @@ check-qfloat: check-qfloat.o qfloat.o $(tools-obj-y)
 check-qjson: check-qjson.o $(qobject-obj-y) $(tools-obj-y)
 test-coroutine: test-coroutine.o qemu-timer-common.o async.o $(coroutine-obj-y) $(tools-obj-y)
 
-test-qmp-input-visitor.o test-qmp-output-visitor.o test-qmp-commands.o qemu-ga$(EXESUF): QEMU_CFLAGS += -I $(qapi-dir)
+test-qmp-input-visitor.o test-qmp-output-visitor.o \
+test-string-input-visitor.o test-string-output-visitor.o \
+	test-qmp-commands.o qemu-ga$(EXESUF): QEMU_CFLAGS += -I $(qapi-dir)
 
 $(qapi-dir)/test-qapi-types.c $(qapi-dir)/test-qapi-types.h :\
 $(SRC_PATH)/qapi-schema-test.json $(SRC_PATH)/scripts/qapi-types.py
@@ -25,6 +27,12 @@ $(SRC_PATH)/qapi-schema-test.json $(SRC_PATH)/scripts/qapi-commands.py
 	    $(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/qapi-commands.py $(gen-out-type) -o "$(qapi-dir)" -p "test-" < $<, "  GEN   $@")
 
 
+test-string-output-visitor.o: $(addprefix $(qapi-dir)/, test-qapi-types.c test-qapi-types.h test-qapi-visit.c test-qapi-visit.h) $(qapi-obj-y)
+test-string-output-visitor: test-string-output-visitor.o $(qobject-obj-y) $(qapi-obj-y) $(tools-obj-y) $(qapi-dir)/test-qapi-visit.o $(qapi-dir)/test-qapi-types.o
+
+test-string-input-visitor.o: $(addprefix $(qapi-dir)/, test-qapi-types.c test-qapi-types.h test-qapi-visit.c test-qapi-visit.h) $(qapi-obj-y)
+test-string-input-visitor: test-string-input-visitor.o $(qobject-obj-y) $(qapi-obj-y) $(tools-obj-y) $(qapi-dir)/test-qapi-visit.o $(qapi-dir)/test-qapi-types.o
+
 test-qmp-output-visitor.o: $(addprefix $(qapi-dir)/, test-qapi-types.c test-qapi-types.h test-qapi-visit.c test-qapi-visit.h) $(qapi-obj-y)
 test-qmp-output-visitor: test-qmp-output-visitor.o $(qobject-obj-y) $(qapi-obj-y) $(tools-obj-y) $(qapi-dir)/test-qapi-visit.o $(qapi-dir)/test-qapi-types.o