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Re: [Qemu-devel] [PATCH 05/26] visitor: pass size of strings array to en
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From: |
Marc-André Lureau |
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Subject: |
Re: [Qemu-devel] [PATCH 05/26] visitor: pass size of strings array to enum visitor |
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Date: |
Tue, 22 Aug 2017 13:17:46 +0200 |
hi
On Wed, Aug 16, 2017 at 2:54 PM, Markus Armbruster <address@hidden> wrote:
> Marc-André Lureau <address@hidden> writes:
>
>> The size is known at compile time, this avoids having to compute to
>> check array boundaries.
>>
>> Additionally, the following conditional enum entry change will create
>> "hole" in the generated _lookup tables, that should be skipped.
>>
>> Signed-off-by: Marc-André Lureau <address@hidden>
>> ---
>> include/qapi/visitor.h | 3 ++-
>> scripts/qapi-visit.py | 10 +++++-----
>> include/hw/qdev-core.h | 1 +
>> include/qom/object.h | 4 ++++
>> qapi/qapi-visit-core.c | 23 ++++++++++++-----------
>> backends/hostmem.c | 1 +
>> crypto/secret.c | 1 +
>> crypto/tlscreds.c | 1 +
>> hw/core/qdev-properties.c | 11 +++++++++--
>> net/filter.c | 1 +
>> qom/object.c | 11 ++++++++---
>> tests/check-qom-proplist.c | 1 +
>> tests/test-qobject-input-visitor.c | 2 +-
>> 13 files changed, 47 insertions(+), 23 deletions(-)
>
> No change to scripts/qapi-types.c. The generated lookup tables continue
> to contain the NULL sentinel. Possibly intentional, because it saves
> you the trouble of searching for uses of FOO_lookup[FOO__MAX].
>
>> diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
>> index fe9faf469f..a2d9786c52 100644
>> --- a/include/qapi/visitor.h
>> +++ b/include/qapi/visitor.h
>> @@ -469,7 +469,8 @@ bool visit_optional(Visitor *v, const char *name, bool
>> *present);
>> * that visit_type_str() must have no unwelcome side effects.
>> */
>> void visit_type_enum(Visitor *v, const char *name, int *obj,
>> - const char *const strings[], Error **errp);
>> + const char *const strings[], int nstrings,
>> + Error **errp);
>>
>> /*
>> * Check if visitor is an input visitor.
>> diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
>> index bd0b742236..60850a6cdd 100644
>> --- a/scripts/qapi-visit.py
>> +++ b/scripts/qapi-visit.py
>> @@ -147,17 +147,17 @@ out:
>> c_name=c_name(name), c_elt_type=element_type.c_name())
>>
>>
>> -def gen_visit_enum(name):
>> +def gen_visit_enum(name, prefix):
>> return mcgen('''
>>
>> void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj,
>> Error **errp)
>> {
>> int value = *obj;
>> - visit_type_enum(v, name, &value, %(c_name)s_lookup, errp);
>> + visit_type_enum(v, name, &value, %(c_name)s_lookup, %(c_max)s, errp);
>> *obj = value;
>> }
>> ''',
>> - c_name=c_name(name))
>> + c_name=c_name(name), c_max=c_enum_const(name, '_MAX',
>> prefix))
>>
>>
>> def gen_visit_alternate(name, variants):
>> @@ -288,10 +288,10 @@ class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
>> if not info:
>> self._btin += gen_visit_decl(name, scalar=True)
>> if do_builtins:
>> - self.defn += gen_visit_enum(name)
>> + self.defn += gen_visit_enum(name, prefix)
>> else:
>> self.decl += gen_visit_decl(name, scalar=True)
>> - self.defn += gen_visit_enum(name)
>> + self.defn += gen_visit_enum(name, prefix)
>>
>> def visit_array_type(self, name, info, element_type):
>> decl = gen_visit_decl(name)
>> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
>> index ae317286a4..f86a0e1a75 100644
>> --- a/include/hw/qdev-core.h
>> +++ b/include/hw/qdev-core.h
>> @@ -250,6 +250,7 @@ struct PropertyInfo {
>> const char *name;
>> const char *description;
>> const char * const *enum_table;
>> + int enum_table_size;
>> int (*print)(DeviceState *dev, Property *prop, char *dest, size_t len);
>> void (*set_default_value)(Object *obj, const Property *prop);
>> void (*create)(Object *obj, Property *prop, Error **errp);
>> diff --git a/include/qom/object.h b/include/qom/object.h
>> index 1b828994fa..53d807e1e6 100644
>> --- a/include/qom/object.h
>> +++ b/include/qom/object.h
>> @@ -1406,6 +1406,8 @@ void object_class_property_add_bool(ObjectClass
>> *klass, const char *name,
>> * @obj: the object to add a property to
>> * @name: the name of the property
>> * @typename: the name of the enum data type
>> + * @strings: an array of strings for the enum
>
> Fixes a preexisting doc buglet.
>
>> + * @nstrings: the size of @strings
>> * @get: the getter or %NULL if the property is write-only.
>> * @set: the setter or %NULL if the property is read-only
>> * @errp: if an error occurs, a pointer to an area to store the error
>> @@ -1416,6 +1418,7 @@ void object_class_property_add_bool(ObjectClass
>> *klass, const char *name,
>> void object_property_add_enum(Object *obj, const char *name,
>> const char *typename,
>> const char * const *strings,
>> + int nstrings,
>> int (*get)(Object *, Error **),
>> void (*set)(Object *, int, Error **),
>> Error **errp);
>> @@ -1423,6 +1426,7 @@ void object_property_add_enum(Object *obj, const char
>> *name,
>> void object_class_property_add_enum(ObjectClass *klass, const char *name,
>> const char *typename,
>> const char * const *strings,
>> + int nstrings,
>> int (*get)(Object *, Error **),
>> void (*set)(Object *, int, Error **),
>> Error **errp);
>> diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
>> index ed6d2af462..dc0b9f2cee 100644
>> --- a/qapi/qapi-visit-core.c
>> +++ b/qapi/qapi-visit-core.c
>> @@ -333,14 +333,13 @@ void visit_type_null(Visitor *v, const char *name,
>> QNull **obj,
>> }
>>
>> static void output_type_enum(Visitor *v, const char *name, int *obj,
>> - const char *const strings[], Error **errp)
>> + const char *const strings[],
>> + int nstrings, Error **errp)
>> {
>> - int i = 0;
>> int value = *obj;
>> char *enum_str;
>>
>> - while (strings[i++] != NULL);
>
> This is the computation we save.
>
>> - if (value < 0 || value >= i - 1) {
>> + if (value < 0 || value >= nstrings) {
>> error_setg(errp, QERR_INVALID_PARAMETER, name ? name : "null");
>> return;
>> }
>> @@ -350,7 +349,8 @@ static void output_type_enum(Visitor *v, const char
>> *name, int *obj,
>> }
>>
>> static void input_type_enum(Visitor *v, const char *name, int *obj,
>> - const char *const strings[], Error **errp)
>> + const char *const strings[],
>> + int nstrings, Error **errp)
>> {
>> Error *local_err = NULL;
>> int64_t value = 0;
>> @@ -362,14 +362,14 @@ static void input_type_enum(Visitor *v, const char
>> *name, int *obj,
>> return;
>> }
>>
>> - while (strings[value] != NULL) {
>
> This is the predicate that becomes invalid when we put holes into
> strings[].
>
>> - if (strcmp(strings[value], enum_str) == 0) {
>> + while (value < nstrings) {
>> + if (strings[value] && strcmp(strings[value], enum_str) == 0) {
>
> I'd prefer !strcmp().
>
>> break;
>> }
>> value++;
>> }
>>
>> - if (strings[value] == NULL) {
>> + if (value >= nstrings || strings[value] == NULL) {
>
> Make that
>
> if (value == nstrings) {
>
> to match the loop above.
>
>> error_setg(errp, QERR_INVALID_PARAMETER, enum_str);
>> g_free(enum_str);
>> return;
>> @@ -380,16 +380,17 @@ static void input_type_enum(Visitor *v, const char
>> *name, int *obj,
>> }
>>
>> void visit_type_enum(Visitor *v, const char *name, int *obj,
>> - const char *const strings[], Error **errp)
>> + const char *const strings[], int nstrings,
>> + Error **errp)
>> {
>> assert(obj && strings);
>> trace_visit_type_enum(v, name, obj);
>> switch (v->type) {
>> case VISITOR_INPUT:
>> - input_type_enum(v, name, obj, strings, errp);
>> + input_type_enum(v, name, obj, strings, nstrings, errp);
>> break;
>> case VISITOR_OUTPUT:
>> - output_type_enum(v, name, obj, strings, errp);
>> + output_type_enum(v, name, obj, strings, nstrings, errp);
>> break;
>> case VISITOR_CLONE:
>> /* nothing further to do, scalar value was already copied by
>> diff --git a/backends/hostmem.c b/backends/hostmem.c
>> index 4606b73849..fc475a5387 100644
>> --- a/backends/hostmem.c
>> +++ b/backends/hostmem.c
>> @@ -396,6 +396,7 @@ host_memory_backend_class_init(ObjectClass *oc, void
>> *data)
>> NULL, NULL, &error_abort);
>> object_class_property_add_enum(oc, "policy", "HostMemPolicy",
>> HostMemPolicy_lookup,
>> + HOST_MEM_POLICY__MAX,
>> host_memory_backend_get_policy,
>> host_memory_backend_set_policy, &error_abort);
>> object_class_property_add_str(oc, "id", get_id, set_id, &error_abort);
>> diff --git a/crypto/secret.c b/crypto/secret.c
>> index 285ab7a63c..b5382cb7e3 100644
>> --- a/crypto/secret.c
>> +++ b/crypto/secret.c
>> @@ -379,6 +379,7 @@ qcrypto_secret_class_init(ObjectClass *oc, void *data)
>> object_class_property_add_enum(oc, "format",
>> "QCryptoSecretFormat",
>> QCryptoSecretFormat_lookup,
>> + QCRYPTO_SECRET_FORMAT__MAX,
>> qcrypto_secret_prop_get_format,
>> qcrypto_secret_prop_set_format,
>> NULL);
>> diff --git a/crypto/tlscreds.c b/crypto/tlscreds.c
>> index a8965531b6..8c060127ea 100644
>> --- a/crypto/tlscreds.c
>> +++ b/crypto/tlscreds.c
>> @@ -234,6 +234,7 @@ qcrypto_tls_creds_class_init(ObjectClass *oc, void *data)
>> object_class_property_add_enum(oc, "endpoint",
>> "QCryptoTLSCredsEndpoint",
>> QCryptoTLSCredsEndpoint_lookup,
>> + QCRYPTO_TLS_CREDS_ENDPOINT__MAX,
>> qcrypto_tls_creds_prop_get_endpoint,
>> qcrypto_tls_creds_prop_set_endpoint,
>> NULL);
>> diff --git a/hw/core/qdev-properties.c b/hw/core/qdev-properties.c
>> index 078fc5d239..696fed5b5b 100644
>> --- a/hw/core/qdev-properties.c
>> +++ b/hw/core/qdev-properties.c
>> @@ -52,7 +52,8 @@ static void get_enum(Object *obj, Visitor *v, const char
>> *name, void *opaque,
>> Property *prop = opaque;
>> int *ptr = qdev_get_prop_ptr(dev, prop);
>>
>> - visit_type_enum(v, prop->name, ptr, prop->info->enum_table, errp);
>> + visit_type_enum(v, prop->name, ptr, prop->info->enum_table,
>> + prop->info->enum_table_size, errp);
>> }
>>
>> static void set_enum(Object *obj, Visitor *v, const char *name, void
>> *opaque,
>> @@ -67,7 +68,8 @@ static void set_enum(Object *obj, Visitor *v, const char
>> *name, void *opaque,
>> return;
>> }
>>
>> - visit_type_enum(v, prop->name, ptr, prop->info->enum_table, errp);
>> + visit_type_enum(v, prop->name, ptr, prop->info->enum_table,
>> + prop->info->enum_table_size, errp);
>> }
>>
>> static void set_default_value_enum(Object *obj, const Property *prop)
>> @@ -586,6 +588,7 @@ const PropertyInfo qdev_prop_on_off_auto = {
>> .name = "OnOffAuto",
>> .description = "on/off/auto",
>> .enum_table = OnOffAuto_lookup,
>> + .enum_table_size = ON_OFF_AUTO__MAX,
>> .get = get_enum,
>> .set = set_enum,
>> .set_default_value = set_default_value_enum,
>> @@ -598,6 +601,7 @@ QEMU_BUILD_BUG_ON(sizeof(LostTickPolicy) != sizeof(int));
>> const PropertyInfo qdev_prop_losttickpolicy = {
>> .name = "LostTickPolicy",
>> .enum_table = LostTickPolicy_lookup,
>> + .enum_table_size = LOST_TICK_POLICY__MAX,
>> .get = get_enum,
>> .set = set_enum,
>> .set_default_value = set_default_value_enum,
>> @@ -612,6 +616,7 @@ const PropertyInfo qdev_prop_blockdev_on_error = {
>> .description = "Error handling policy, "
>> "report/ignore/enospc/stop/auto",
>> .enum_table = BlockdevOnError_lookup,
>> + .enum_table_size = BLOCKDEV_ON_ERROR__MAX,
>> .get = get_enum,
>> .set = set_enum,
>> .set_default_value = set_default_value_enum,
>> @@ -626,6 +631,7 @@ const PropertyInfo qdev_prop_bios_chs_trans = {
>> .description = "Logical CHS translation algorithm, "
>> "auto/none/lba/large/rechs",
>> .enum_table = BiosAtaTranslation_lookup,
>> + .enum_table_size = BIOS_ATA_TRANSLATION__MAX,
>> .get = get_enum,
>> .set = set_enum,
>> .set_default_value = set_default_value_enum,
>> @@ -638,6 +644,7 @@ const PropertyInfo qdev_prop_fdc_drive_type = {
>> .description = "FDC drive type, "
>> "144/288/120/none/auto",
>> .enum_table = FloppyDriveType_lookup,
>> + .enum_table_size = FLOPPY_DRIVE_TYPE__MAX,
>> .get = get_enum,
>> .set = set_enum,
>> .set_default_value = set_default_value_enum,
>> diff --git a/net/filter.c b/net/filter.c
>> index 1dfd2caa23..cf62851344 100644
>> --- a/net/filter.c
>> +++ b/net/filter.c
>> @@ -180,6 +180,7 @@ static void netfilter_init(Object *obj)
>> NULL);
>> object_property_add_enum(obj, "queue", "NetFilterDirection",
>> NetFilterDirection_lookup,
>> + NET_FILTER_DIRECTION__MAX,
>> netfilter_get_direction,
>> netfilter_set_direction,
>> NULL);
>> object_property_add_str(obj, "status",
>> diff --git a/qom/object.c b/qom/object.c
>> index fe6e744b4d..425bae3a2a 100644
>> --- a/qom/object.c
>> +++ b/qom/object.c
>> @@ -1247,6 +1247,7 @@ uint64_t object_property_get_uint(Object *obj, const
>> char *name,
>>
>> typedef struct EnumProperty {
>> const char * const *strings;
>> + int nstrings;
>> int (*get)(Object *, Error **);
>> void (*set)(Object *, int, Error **);
>> } EnumProperty;
>> @@ -1284,7 +1285,7 @@ int object_property_get_enum(Object *obj, const char
>> *name,
>> visit_complete(v, &str);
>> visit_free(v);
>> v = string_input_visitor_new(str);
>> - visit_type_enum(v, name, &ret, enumprop->strings, errp);
>> + visit_type_enum(v, name, &ret, enumprop->strings, enumprop->nstrings,
>> errp);
>
> Long line.
>
>>
>> g_free(str);
>> visit_free(v);
>> @@ -1950,7 +1951,7 @@ static void property_get_enum(Object *obj, Visitor *v,
>> const char *name,
>> return;
>> }
>>
>> - visit_type_enum(v, name, &value, prop->strings, errp);
>> + visit_type_enum(v, name, &value, prop->strings, prop->nstrings, errp);
>> }
>>
>> static void property_set_enum(Object *obj, Visitor *v, const char *name,
>> @@ -1960,7 +1961,7 @@ static void property_set_enum(Object *obj, Visitor *v,
>> const char *name,
>> int value;
>> Error *err = NULL;
>>
>> - visit_type_enum(v, name, &value, prop->strings, &err);
>> + visit_type_enum(v, name, &value, prop->strings, prop->nstrings, &err);
>> if (err) {
>> error_propagate(errp, err);
>> return;
>> @@ -1978,6 +1979,7 @@ static void property_release_enum(Object *obj, const
>> char *name,
>> void object_property_add_enum(Object *obj, const char *name,
>> const char *typename,
>> const char * const *strings,
>> + int nstrings,
>> int (*get)(Object *, Error **),
>> void (*set)(Object *, int, Error **),
>> Error **errp)
>> @@ -1986,6 +1988,7 @@ void object_property_add_enum(Object *obj, const char
>> *name,
>> EnumProperty *prop = g_malloc(sizeof(*prop));
>>
>> prop->strings = strings;
>> + prop->nstrings = nstrings;
>> prop->get = get;
>> prop->set = set;
>>
>> @@ -2003,6 +2006,7 @@ void object_property_add_enum(Object *obj, const char
>> *name,
>> void object_class_property_add_enum(ObjectClass *klass, const char *name,
>> const char *typename,
>> const char * const *strings,
>> + int nstrings,
>> int (*get)(Object *, Error **),
>> void (*set)(Object *, int, Error **),
>> Error **errp)
>> @@ -2011,6 +2015,7 @@ void object_class_property_add_enum(ObjectClass
>> *klass, const char *name,
>> EnumProperty *prop = g_malloc(sizeof(*prop));
>>
>> prop->strings = strings;
>> + prop->nstrings = nstrings;
>> prop->get = get;
>> prop->set = set;
>>
>> diff --git a/tests/check-qom-proplist.c b/tests/check-qom-proplist.c
>> index 432b66585f..1179030248 100644
>> --- a/tests/check-qom-proplist.c
>> +++ b/tests/check-qom-proplist.c
>> @@ -143,6 +143,7 @@ static void dummy_class_init(ObjectClass *cls, void
>> *data)
>> object_class_property_add_enum(cls, "av",
>> "DummyAnimal",
>> dummy_animal_map,
>> + DUMMY_LAST,
>> dummy_get_av,
>> dummy_set_av,
>> NULL);
>> diff --git a/tests/test-qobject-input-visitor.c
>> b/tests/test-qobject-input-visitor.c
>> index 1969733971..4da5d02c35 100644
>> --- a/tests/test-qobject-input-visitor.c
>> +++ b/tests/test-qobject-input-visitor.c
>> @@ -1110,7 +1110,7 @@ static void
>> test_visitor_in_fail_struct_missing(TestInputVisitorData *data,
>> error_free_or_abort(&err);
>> visit_optional(v, "optional", &present);
>> g_assert(!present);
>> - visit_type_enum(v, "enum", &en, EnumOne_lookup, &err);
>> + visit_type_enum(v, "enum", &en, EnumOne_lookup, ENUM_ONE__MAX, &err);
>> error_free_or_abort(&err);
>> visit_type_int(v, "i64", &i64, &err);
>> error_free_or_abort(&err);
>
> Missing: a review of FOO_lookup[] uses outside these two, to make sure
> none of them fall into holes like input_type_enum() would. From the top
> of my head: qapi_enum_parse(). A quick grep for loops counting up to
> FOO__MAX additionally finds get_event_by_name() in blkdebug.c,
> parse_read_pattern() in quorum.c, hmp_migrate_set_capability() in hmp.c,
> and then I stopped looking. Most (or all?) of them should use
> qapi_enum_parse().
>
> There's one patch hunk to make input_type_enum() cope with holes, one
> patch hunk to opportunistically simplify output_type_enum(), and all the
> others are for plumbing the table size to these two. That's a lot of
> plumbing. Can't say I like it.
>
> Alternatives:
>
> (1) Use a value other than NULL for holes, say ""
>
> (2) Use a value other than NULL for the sentinel, say ""
>
> (3) Store the length in the lookup table, i.e. change it from
> const char *const[] to struct { int n, const char *const s[] }.
>
> The least work is probably (1). Slightly ugly.
>
> If you do (3), please consider getting rid of the sentinel.
>
I have done (3)
--
Marc-André Lureau