I haven't been able to follow the evolution of this series, my apologies
if I'm missing things already discussed.
Alon Levy<address@hidden> writes:
Example usage:
EnumTable foo_enum_table[] = {
{"bar", 1},
{"buz", 2},
{NULL, 0},
};
DEFINE_PROP_ENUM("foo", State, foo, 1, foo_enum_table)
When using qemu -device foodev,? it will appear as:
foodev.foo=bar/buz
Signed-off-by: Alon Levy<address@hidden>
---
hw/qdev-properties.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++
hw/qdev.h | 15 ++++++++++++
2 files changed, 75 insertions(+), 0 deletions(-)
diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
index a493087..3157721 100644
--- a/hw/qdev-properties.c
+++ b/hw/qdev-properties.c
@@ -63,6 +63,66 @@ PropertyInfo qdev_prop_bit = {
.print = print_bit,
};
+/* --- Enumeration --- */
+/* Example usage:
+EnumTable foo_enum_table[] = {
+ {"bar", 1},
+ {"buz", 2},
+ {NULL, 0},
+};
+DEFINE_PROP_ENUM("foo", State, foo, 1, foo_enum_table),
+ */
+static int parse_enum(DeviceState *dev, Property *prop, const char *str)
+{
+ uint8_t *ptr = qdev_get_prop_ptr(dev, prop);
uint8_t is inconsistent with print_enum() and DEFINE_PROP_ENUM(), which
both use uint32_t.
+ EnumTable *option = (EnumTable*)prop->data;
Please don't cast from void * to pointer type (this isn't C++).
Not thrilled about the "void *data", to be honest. Smells like
premature generality to me.
+
+ while (option->name != NULL) {
+ if (!strncmp(str, option->name, strlen(option->name))) {
Why strncmp() and not straight strcmp()?
+ *ptr = option->value;
+ return 0;
+ }
+ option++;
+ }
+ return -EINVAL;
+}
+
+static int print_enum(DeviceState *dev, Property *prop, char *dest, size_t len)
+{
+ uint32_t *p = qdev_get_prop_ptr(dev, prop);
+ EnumTable *option = (EnumTable*)prop->data;
+ while (option->name != NULL) {
+ if (*p == option->value) {
+ return snprintf(dest, len, "%s", option->name);
+ }
+ option++;
+ }
+ return 0;
Bug: must dest[0] = 0 when returning 0.
+}
+
+static int print_enum_options(DeviceInfo *info, Property *prop, char *dest,
size_t len)
+{
+ int ret = 0;
+ EnumTable *option = (EnumTable*)prop->data;
Please don't cast from void * to pointer type (this isn't C++).
+ while (option->name != NULL) {
+ ret += snprintf(dest + ret, len - ret, "%s", option->name);
+ if (option[1].name != NULL) {
+ ret += snprintf(dest + ret, len - ret, "/");
+ }
+ option++;
+ }
+ return ret;
+}
+
+PropertyInfo qdev_prop_enum = {
+ .name = "enum",
+ .type = PROP_TYPE_ENUM,
+ .size = sizeof(uint32_t),
+ .parse = parse_enum,
+ .print = print_enum,
+ .print_options = print_enum_options,
+};
+
/* --- 8bit integer --- */
static int parse_uint8(DeviceState *dev, Property *prop, const char *str)
diff --git a/hw/qdev.h b/hw/qdev.h
index 3d9acd7..3701d83 100644
--- a/hw/qdev.h
+++ b/hw/qdev.h
@@ -102,6 +102,7 @@ enum PropertyType {
PROP_TYPE_VLAN,
PROP_TYPE_PTR,
PROP_TYPE_BIT,
+ PROP_TYPE_ENUM,
};
struct PropertyInfo {
@@ -121,6 +122,11 @@ typedef struct GlobalProperty {
QTAILQ_ENTRY(GlobalProperty) next;
} GlobalProperty;
+typedef struct EnumTable {
+ const char *name;
+ uint32_t value;
+} EnumTable;
+
/*** Board API. This should go away once we have a machine config file. ***/
DeviceState *qdev_create(BusState *bus, const char *name);
@@ -235,6 +241,7 @@ extern PropertyInfo qdev_prop_drive;
extern PropertyInfo qdev_prop_netdev;
extern PropertyInfo qdev_prop_vlan;
extern PropertyInfo qdev_prop_pci_devfn;
+extern PropertyInfo qdev_prop_enum;
#define DEFINE_PROP(_name, _state, _field, _prop, _type) { \
.name = (_name), \
@@ -257,6 +264,14 @@ extern PropertyInfo qdev_prop_pci_devfn;
+ type_check(uint32_t,typeof_field(_state, _field)), \
.defval = (bool[]) { (_defval) }, \
}
+#define DEFINE_PROP_ENUM(_name, _state, _field, _defval, _options) { \
+ .name = (_name), \
+ .info =&(qdev_prop_enum), \
+ .offset = offsetof(_state, _field) \
+ + type_check(uint32_t,typeof_field(_state, _field)), \
+ .defval = (uint32_t[]) { (_defval) }, \
+ .data = (void*)(_options), \
Please don't cast from pointer type to void * (this isn't C++). If
someone accidentally passes an integral argument for _options (forgotten
operator&), the cast suppresses the warning.
+ }
#define DEFINE_PROP_UINT8(_n, _s, _f, _d) \
DEFINE_PROP_DEFAULT(_n, _s, _f, _d, qdev_prop_uint8, uint8_t)
Okay, let's examine how your enumeration properties work.
An enumeration property describes a uint32_t field of the state object.
Differences to ordinary properties defined with DEFINE_PROP_UINT32:
* info is qdev_prop_enum instead of qdev_prop_uint32. Differences
between the two:
- parse, print: symbolic names vs. numbers
- name, print_options: only for -device DRIVER,\? (and name's use
there isn't particularly helpful)
* data points to an EnumTable, which is a map string<-> number. Thus,
the actual enumeration is attached to the property declaration, not
the property type (in programming languages, we commonly attach it to
the type, not the variable declaration). Since it's a table it can be
used for multiple properties with minimal fuss. Works for me.
What if we want to enumerate values of fields with types other than
uint32_t?
C enumeration types, in particular. Tricky, because width and
signedness of enum types is implementation-defined, and different enum
types may differ there.
Perhaps what we really need is a way to define arbitrary integer type
properties with an EnumTable attached.