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[Qemu-devel] [PATCH RFC v3 06/20] qapi: Simplify visiting of alternate t
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PATCH RFC v3 06/20] qapi: Simplify visiting of alternate types |
Date: |
Tue, 18 Aug 2015 07:19:48 -0700 |
Previously, working with alternates required two enums, and
some indirection: for type Foo, we created Foo_qtypes[] which
maps each qtype to a member of FooKind_lookup[], then use
FooKind_lookup[] like we do for other union types.
This has a subtle bug: since the values of FooKind_lookup
start at zero, all entries of Foo_qtypes that were not
explicitly initialized map to the same branch of the union as
the first member of the alternate, rather than triggering a
failure in visit_get_next_type(). Fortunately, the bug
seldom bites; the very next thing the input visitor does is
try to parse the incoming JSON with the wrong parser, which
fails; the output visitor is not used with a C struct in that
state, and the dealloc visitor has nothing to clean up (so
there is no leak).
However, it IS observable in one case: the behavior of an
alternate that contains a 'number' member but no 'int' member
differs according to whether the 'number' was first in the
qapi definition, and when the input being parsed is an integer;
this is because the 'number' parser accepts QTYPE_QINT in
addition to the expected QTYPE_QFLOAT. A later patch will worry
about fixing alternates to parse all inputs that a non-alternate
'number' would accept.
This patch fixes the validation bug by deleting the indirection,
and modifying get_next_type() to directly return a qtype code.
There is no longer a need to generate an implicit FooKind array
associated with the alternate type (since the QMP wire format
never uses the stringized counterparts of the C union member
names). Next, the generated visitor is fixed to properly detect
unexpected qtypes in the switch statement. Things got a bit
tricky with validating QAPISchemaObjectTypeVariants, which now
has three different initialization paths; but I didn't think it
was confusing enough to need to create different sub-classes.
Callers now have to know the QTYPE_* mapping when looking at the
discriminator; but so far, only the testsuite was even using the
C struct of an alternate types. If that gets too confusing, we
could reintroduce FooKind, but initialize it differently than
most generated arrays, as in:
typedef enum FooKind {
FOO_KIND_A = QTYPE_QDICT,
FOO_KIND_B = QTYPE_QINT,
} FooKind;
to create nicer aliases for knowing when to use foo->a or foo->b
when inspecting foo->kind. But without a current client, I
didn't see the point of doing it now.
There is a user-visible side effect to this change, but I
consider it to be an improvement. Previously,
the invalid QMP command:
{"execute":"blockdev-add", "arguments":{"options":
{"driver":"raw", "id":"a", "file":true}}}
failed with:
{"error": {"class": "GenericError",
"desc": "Invalid parameter type for 'file', expected: QDict"}}
Now it fails with:
{"error": {"class": "GenericError",
"desc": "Invalid parameter type for 'file', expected: BlockdevRef"}}
Signed-off-by: Eric Blake <address@hidden>
---
docs/qapi-code-gen.txt | 3 ---
include/qapi/visitor-impl.h | 2 +-
include/qapi/visitor.h | 2 +-
qapi/qapi-visit-core.c | 4 ++--
qapi/qmp-input-visitor.c | 4 ++--
scripts/qapi-types.py | 39 ++++++----------------------------
scripts/qapi-visit.py | 12 ++++++-----
scripts/qapi.py | 21 +++++++++++-------
tests/qapi-schema/alternate-good.out | 1 -
tests/qapi-schema/qapi-schema-test.out | 8 -------
tests/test-qmp-input-visitor.c | 26 +++++++++++------------
tests/test-qmp-output-visitor.c | 21 +++++++++++++-----
12 files changed, 61 insertions(+), 82 deletions(-)
diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index 3a78cf4..5dd08e5 100644
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -372,9 +372,6 @@ where each branch of the union names a QAPI type. For
example:
'data': { 'definition': 'BlockdevOptions',
'reference': 'str' } }
-Just like for a simple union, an implicit C enum 'NameKind' is created
-to enumerate the branches for the alternate 'Name'.
-
Unlike a union, the discriminator string is never passed on the wire
for the Client JSON Protocol. Instead, the value's JSON type serves
as an implicit discriminator, which in turn means that an alternate
diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index 8c0ba57..7098b93 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -32,7 +32,7 @@ struct Visitor
void (*type_enum)(Visitor *v, int *obj, const char * const strings[],
const char *kind, const char *name, Error **errp);
- void (*get_next_type)(Visitor *v, int *kind, const int *qobjects,
+ void (*get_next_type)(Visitor *v, qtype_code *type,
const char *name, Error **errp);
void (*type_int)(Visitor *v, int64_t *obj, const char *name, Error **errp);
diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
index cfc19a6..f1ac5c4 100644
--- a/include/qapi/visitor.h
+++ b/include/qapi/visitor.h
@@ -41,7 +41,7 @@ GenericList *visit_next_list(Visitor *v, GenericList **list,
Error **errp);
void visit_end_list(Visitor *v, Error **errp);
void visit_optional(Visitor *v, bool *present, const char *name,
Error **errp);
-void visit_get_next_type(Visitor *v, int *obj, const int *qtypes,
+void visit_get_next_type(Visitor *v, qtype_code *type,
const char *name, Error **errp);
void visit_type_enum(Visitor *v, int *obj, const char * const strings[],
const char *kind, const char *name, Error **errp);
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index 59ed506..3f24daa 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -81,11 +81,11 @@ void visit_optional(Visitor *v, bool *present, const char
*name,
}
}
-void visit_get_next_type(Visitor *v, int *obj, const int *qtypes,
+void visit_get_next_type(Visitor *v, qtype_code *type,
const char *name, Error **errp)
{
if (v->get_next_type) {
- v->get_next_type(v, obj, qtypes, name, errp);
+ v->get_next_type(v, type, name, errp);
}
}
diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index 5dd9ed5..803ffad 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -208,7 +208,7 @@ static void qmp_input_end_list(Visitor *v, Error **errp)
qmp_input_pop(qiv, errp);
}
-static void qmp_input_get_next_type(Visitor *v, int *kind, const int *qobjects,
+static void qmp_input_get_next_type(Visitor *v, qtype_code *type,
const char *name, Error **errp)
{
QmpInputVisitor *qiv = to_qiv(v);
@@ -218,7 +218,7 @@ static void qmp_input_get_next_type(Visitor *v, int *kind,
const int *qobjects,
error_setg(errp, QERR_MISSING_PARAMETER, name ? name : "null");
return;
}
- *kind = qobjects[qobject_type(qobj)];
+ *type = qobject_type(qobj);
}
static void qmp_input_type_int(Visitor *v, int64_t *obj, const char *name,
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index 27ad0c1..b0785a5 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -88,36 +88,6 @@ struct %(c_name)s {
return ret
-def gen_alternate_qtypes_decl(name):
- return mcgen('''
-
-extern const int %(c_name)s_qtypes[];
-''',
- c_name=c_name(name))
-
-def gen_alternate_qtypes(name, variants):
- ret = mcgen('''
-
-const int %(c_name)s_qtypes[QTYPE_MAX] = {
-''',
- c_name=c_name(name))
-
- for var in variants.variants:
- qtype = var.type.alternate_qtype()
- assert qtype
-
- ret += mcgen('''
- [%(qtype)s] = %(enum_const)s,
-''',
- qtype=qtype,
- enum_const=c_enum_const(variants.tag_member.type.name,
- var.name))
-
- ret += mcgen('''
-};
-''')
- return ret
-
def gen_union(name, base, variants):
ret = mcgen('''
@@ -126,6 +96,10 @@ struct %(c_name)s {
c_name=c_name(name))
if base:
ret += gen_struct_fields([], base)
+ elif not variants.tag_member:
+ ret += mcgen('''
+ qtype_code type;
+''')
else:
ret += mcgen('''
%(c_type)s type;
@@ -144,7 +118,8 @@ struct %(c_name)s {
union { /* union tag is @%(c_name)s */
void *data;
''',
- c_name=c_name(variants.tag_member.name))
+ c_name=c_name((variants.tag_member and
+ variants.tag_member.name) or 'type'))
for var in variants.variants:
# TODO ugly special case for simple union
@@ -244,9 +219,7 @@ class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
self._gen_type_cleanup(name)
def visit_alternate_type(self, name, info, variants):
self.fwdecl += gen_fwd_object_or_array(name)
- self.fwdefn += gen_alternate_qtypes(name, variants)
self.decl += gen_union(name, None, variants)
- self.decl += gen_alternate_qtypes_decl(name)
self._gen_type_cleanup(name)
# If you link code generated from multiple schemata, you want only one
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index b131c0d..06a27c5 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -203,7 +203,7 @@ void visit_type_%(c_name)s(Visitor *m, %(c_name)s **obj,
const char *name, Error
if (err) {
goto out;
}
- visit_get_next_type(m, (int*) &(*obj)->type, %(c_name)s_qtypes, name,
&err);
+ visit_get_next_type(m, &(*obj)->type, name, &err);
if (err) {
goto out_end;
}
@@ -217,14 +217,14 @@ void visit_type_%(c_name)s(Visitor *m, %(c_name)s **obj,
const char *name, Error
visit_type_%(c_type)s(m, &(*obj)->%(c_name)s, name, &err);
break;
''',
- case=c_enum_const(variants.tag_member.type.name,
- var.name),
+ case=var.type.alternate_qtype(),
c_type=var.type.c_name(),
c_name=c_name(var.name))
ret += mcgen('''
default:
- abort();
+ error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
+ "%(name)s");
}
out_end:
error_propagate(errp, err);
@@ -233,7 +233,8 @@ out_end:
out:
error_propagate(errp, err);
}
-''')
+''',
+ name=name)
return ret
@@ -427,6 +428,7 @@ fdef.write(mcgen('''
fdecl.write(mcgen('''
#include "qapi/visitor.h"
+#include "qapi/qmp/qerror.h"
#include "%(prefix)sqapi-types.h"
''',
diff --git a/scripts/qapi.py b/scripts/qapi.py
index 99ea61d..6f41ae0 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -929,29 +929,35 @@ class QAPISchemaObjectTypeVariants(object):
for v in variants:
assert isinstance(v, QAPISchemaObjectTypeVariant)
self.tag_name = tag_name
- if tag_name:
+ if tag_name: # flat union
assert not tag_enum
self.tag_member = None
- else:
+ elif tag_enum: # simple union
self.tag_member = QAPISchemaObjectTypeMember('type', tag_enum,
False)
+ else: # alternate
+ self.tag_member = None
self.variants = variants
def check(self, schema, members, seen):
if self.tag_name:
self.tag_member = seen[self.tag_name]
- else:
+ elif self.tag_member:
self.tag_member.check(schema, members, seen)
- assert isinstance(self.tag_member.type, QAPISchemaEnumType)
+ typ = None
+ if self.tag_member:
+ assert isinstance(self.tag_member.type, QAPISchemaEnumType)
+ typ = self.tag_member.type
for v in self.variants:
vseen = dict(seen)
- v.check(schema, self.tag_member.type, vseen)
+ v.check(schema, typ, vseen)
class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember):
def __init__(self, name, typ):
QAPISchemaObjectTypeMember.__init__(self, name, typ, False)
def check(self, schema, tag_type, seen):
QAPISchemaObjectTypeMember.check(self, schema, [], seen)
- assert self.name in tag_type.values
+ if tag_type:
+ assert self.name in tag_type.values
# TODO try to get rid of .simple_union_type()
def simple_union_type(self):
if isinstance(self.type, QAPISchemaObjectType) and not self.type.info:
@@ -1146,10 +1152,9 @@ class QAPISchema(object):
data = expr['data']
variants = [self._make_variant(key, data[key])
for key in data.keys()]
- tag_enum = self._make_tag_enum(name, variants)
self._def_entity(QAPISchemaAlternateType(name, info,
QAPISchemaObjectTypeVariants(None,
- tag_enum,
+ None,
variants)))
self._make_array_type(name) # TODO really needed?
diff --git a/tests/qapi-schema/alternate-good.out
b/tests/qapi-schema/alternate-good.out
index 65af727..d211aba 100644
--- a/tests/qapi-schema/alternate-good.out
+++ b/tests/qapi-schema/alternate-good.out
@@ -3,7 +3,6 @@ alternate Alt
case value: int
case string: Enum
case struct: Data
-enum AltKind ['value', 'string', 'struct']
object Data
member number: int optional=True
member name: str optional=True
diff --git a/tests/qapi-schema/qapi-schema-test.out
b/tests/qapi-schema/qapi-schema-test.out
index ba70ea7..f062a15 100644
--- a/tests/qapi-schema/qapi-schema-test.out
+++ b/tests/qapi-schema/qapi-schema-test.out
@@ -54,27 +54,21 @@ object :obj-user_def_cmd3-arg
alternate AltFive
case i: int
case n: number
-enum AltFiveKind ['i', 'n']
alternate AltFour
case s: str
case i: int
-enum AltFourKind ['s', 'i']
alternate AltOne
case s: str
case b: bool
-enum AltOneKind ['s', 'b']
alternate AltSix
case n: number
case i: int
-enum AltSixKind ['n', 'i']
alternate AltThree
case n: number
case s: str
-enum AltThreeKind ['n', 's']
alternate AltTwo
case s: str
case n: number
-enum AltTwoKind ['s', 'n']
event EVENT_A None
event EVENT_B None
event EVENT_C :obj-EVENT_C-arg
@@ -95,7 +89,6 @@ alternate UserDefAlternate
case uda: UserDefA
case s: str
case i: int
-enum UserDefAlternateKind ['uda', 's', 'i']
object UserDefB
member intb: int optional=False
object UserDefC
@@ -158,7 +151,6 @@ event __ORG.QEMU_X-EVENT __org.qemu_x-Struct
alternate __org.qemu_x-Alt
case __org.qemu_x-branch: str
case b: __org.qemu_x-Base
-enum __org.qemu_x-AltKind ['__org.qemu_x-branch', 'b']
object __org.qemu_x-Base
member __org.qemu_x-member1: __org.qemu_x-Enum optional=False
enum __org.qemu_x-Enum ['__org.qemu_x-value']
diff --git a/tests/test-qmp-input-visitor.c b/tests/test-qmp-input-visitor.c
index 3ee1a1a..cd833a4 100644
--- a/tests/test-qmp-input-visitor.c
+++ b/tests/test-qmp-input-visitor.c
@@ -373,7 +373,7 @@ static void test_visitor_in_alternate(TestInputVisitorData
*data,
v = visitor_input_test_init(data, "42");
visit_type_UserDefAlternate(v, &tmp, NULL, &error_abort);
- g_assert_cmpint(tmp->type, ==, USER_DEF_ALTERNATE_KIND_I);
+ g_assert_cmpint(tmp->type, ==, QTYPE_QINT);
g_assert_cmpint(tmp->i, ==, 42);
qapi_free_UserDefAlternate(tmp);
tmp = NULL;
@@ -381,7 +381,7 @@ static void test_visitor_in_alternate(TestInputVisitorData
*data,
v = visitor_input_test_init(data, "'string'");
visit_type_UserDefAlternate(v, &tmp, NULL, &error_abort);
- g_assert_cmpint(tmp->type, ==, USER_DEF_ALTERNATE_KIND_S);
+ g_assert_cmpint(tmp->type, ==, QTYPE_QSTRING);
g_assert_cmpstr(tmp->s, ==, "string");
qapi_free_UserDefAlternate(tmp);
tmp = NULL;
@@ -424,31 +424,31 @@ static void
test_visitor_in_alternate_number(TestInputVisitorData *data,
qapi_free_AltTwo(two);
one = NULL;
- /* FIXME: Order of alternate should not affect semantics */
v = visitor_input_test_init(data, "42");
- visit_type_AltThree(v, &three, NULL, &error_abort);
- g_assert_cmpint(three->type, ==, ALT_THREE_KIND_N);
- g_assert_cmpfloat(three->n, ==, 42);
+ visit_type_AltThree(v, &three, NULL, &err);
+ g_assert(err);
+ error_free(err);
+ err = NULL;
qapi_free_AltThree(three);
one = NULL;
v = visitor_input_test_init(data, "42");
visit_type_AltFour(v, &four, NULL, &error_abort);
- g_assert_cmpint(four->type, ==, ALT_FOUR_KIND_I);
+ g_assert_cmpint(four->type, ==, QTYPE_QINT);
g_assert_cmpint(four->i, ==, 42);
qapi_free_AltFour(four);
one = NULL;
v = visitor_input_test_init(data, "42");
visit_type_AltFive(v, &five, NULL, &error_abort);
- g_assert_cmpint(five->type, ==, ALT_FIVE_KIND_I);
+ g_assert_cmpint(five->type, ==, QTYPE_QINT);
g_assert_cmpint(five->i, ==, 42);
qapi_free_AltFive(five);
one = NULL;
v = visitor_input_test_init(data, "42");
visit_type_AltSix(v, &six, NULL, &error_abort);
- g_assert_cmpint(six->type, ==, ALT_SIX_KIND_I);
+ g_assert_cmpint(six->type, ==, QTYPE_QINT);
g_assert_cmpint(six->i, ==, 42);
qapi_free_AltSix(six);
one = NULL;
@@ -465,14 +465,14 @@ static void
test_visitor_in_alternate_number(TestInputVisitorData *data,
v = visitor_input_test_init(data, "42.5");
visit_type_AltTwo(v, &two, NULL, &error_abort);
- g_assert_cmpint(two->type, ==, ALT_TWO_KIND_N);
+ g_assert_cmpint(two->type, ==, QTYPE_QFLOAT);
g_assert_cmpfloat(two->n, ==, 42.5);
qapi_free_AltTwo(two);
two = NULL;
v = visitor_input_test_init(data, "42.5");
visit_type_AltThree(v, &three, NULL, &error_abort);
- g_assert_cmpint(three->type, ==, ALT_THREE_KIND_N);
+ g_assert_cmpint(three->type, ==, QTYPE_QFLOAT);
g_assert_cmpfloat(three->n, ==, 42.5);
qapi_free_AltThree(three);
three = NULL;
@@ -487,14 +487,14 @@ static void
test_visitor_in_alternate_number(TestInputVisitorData *data,
v = visitor_input_test_init(data, "42.5");
visit_type_AltFive(v, &five, NULL, &error_abort);
- g_assert_cmpint(five->type, ==, ALT_FIVE_KIND_N);
+ g_assert_cmpint(five->type, ==, QTYPE_QFLOAT);
g_assert_cmpfloat(five->n, ==, 42.5);
qapi_free_AltFive(five);
five = NULL;
v = visitor_input_test_init(data, "42.5");
visit_type_AltSix(v, &six, NULL, &error_abort);
- g_assert_cmpint(six->type, ==, ALT_SIX_KIND_N);
+ g_assert_cmpint(six->type, ==, QTYPE_QFLOAT);
g_assert_cmpint(six->n, ==, 42.5);
qapi_free_AltSix(six);
six = NULL;
diff --git a/tests/test-qmp-output-visitor.c b/tests/test-qmp-output-visitor.c
index ab4bc5d..2b5c8d5 100644
--- a/tests/test-qmp-output-visitor.c
+++ b/tests/test-qmp-output-visitor.c
@@ -510,20 +510,31 @@ static void
test_visitor_out_alternate(TestOutputVisitorData *data,
const void *unused)
{
QObject *arg;
- Error *err = NULL;
+ UserDefAlternate *tmp;
- UserDefAlternate *tmp = g_malloc0(sizeof(UserDefAlternate));
- tmp->type = USER_DEF_ALTERNATE_KIND_I;
+ tmp = g_malloc0(sizeof(UserDefAlternate));
+ tmp->type = QTYPE_QINT;
tmp->i = 42;
- visit_type_UserDefAlternate(data->ov, &tmp, NULL, &err);
- g_assert(err == NULL);
+ visit_type_UserDefAlternate(data->ov, &tmp, NULL, &error_abort);
arg = qmp_output_get_qobject(data->qov);
g_assert(qobject_type(arg) == QTYPE_QINT);
g_assert_cmpint(qint_get_int(qobject_to_qint(arg)), ==, 42);
qapi_free_UserDefAlternate(tmp);
+
+ tmp = g_malloc0(sizeof(UserDefAlternate));
+ tmp->type = QTYPE_QSTRING;
+ tmp->s = g_strdup("hello");
+
+ visit_type_UserDefAlternate(data->ov, &tmp, NULL, &error_abort);
+ arg = qmp_output_get_qobject(data->qov);
+
+ g_assert(qobject_type(arg) == QTYPE_QSTRING);
+ g_assert_cmpstr(qstring_get_str(qobject_to_qstring(arg)), ==, "hello");
+
+ qapi_free_UserDefAlternate(tmp);
}
static void test_visitor_out_empty(TestOutputVisitorData *data,
--
2.4.3
- [Qemu-devel] [PATCH RFC v3 00/20] post-introspection qapi cleanups, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 05/20] qapi: Test use of 'number' within alternates, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 01/20] qapi: use 'type' in generated C code to match QMP union wire form, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 06/20] qapi: Simplify visiting of alternate types,
Eric Blake <=
- [Qemu-devel] [PATCH RFC v3 07/20] qapi: Fix alternates that accept 'number' but not 'int', Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 09/20] qapi: Use consistent generated code patterns, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 08/20] qapi: Don't pass pre-existing error to later call, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 10/20] qapi: Add tests for empty unions, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 11/20] qapi: Rework deallocation of partial struct, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 04/20] qapi-visit: Remove redundant functions for flat union base, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 03/20] qapi: Unbox base members, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 02/20] vnc: hoist allocation of VncBasicInfo to callers, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 15/20] qapi: Remove dead visitor code, Eric Blake, 2015/08/18
- [Qemu-devel] [PATCH RFC v3 20/20] qapi: Support boxed unions, Eric Blake, 2015/08/18