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[PATCH 5/6] qapi: Add support for aliases
|
From: |
Kevin Wolf |
|
Subject: |
[PATCH 5/6] qapi: Add support for aliases |
|
Date: |
Thu, 12 Nov 2020 18:28:49 +0100 |
Introduce alias definitions for object types (structs and unions). This
allows using the same QAPI type and visitor for many syntax variations
that exist in the external representation, like between QMP and the
command line. It also provides a new tool for evolving the schema while
maintaining backwards compatibility during a deprecation period.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
docs/devel/qapi-code-gen.txt | 37 +++++++++++++++++++++++---
docs/sphinx/qapidoc.py | 2 +-
scripts/qapi/expr.py | 34 +++++++++++++++++++++--
scripts/qapi/schema.py | 27 +++++++++++++++----
scripts/qapi/types.py | 4 ++-
scripts/qapi/visit.py | 33 ++++++++++++++++++++---
tests/qapi-schema/test-qapi.py | 7 ++++-
tests/qapi-schema/double-type.err | 2 +-
tests/qapi-schema/unknown-expr-key.err | 2 +-
9 files changed, 130 insertions(+), 18 deletions(-)
diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt
index 6906a06ad2..6da14d5275 100644
--- a/docs/devel/qapi-code-gen.txt
+++ b/docs/devel/qapi-code-gen.txt
@@ -231,7 +231,8 @@ Syntax:
'data': MEMBERS,
'*base': STRING,
'*if': COND,
- '*features': FEATURES }
+ '*features': FEATURES,
+ '*aliases': ALIASES }
MEMBERS = { MEMBER, ... }
MEMBER = STRING : TYPE-REF
| STRING : { 'type': TYPE-REF,
@@ -286,13 +287,15 @@ Syntax:
UNION = { 'union': STRING,
'data': BRANCHES,
'*if': COND,
- '*features': FEATURES }
+ '*features': FEATURES,
+ '*aliases': ALIASES }
| { 'union': STRING,
'data': BRANCHES,
'base': ( MEMBERS | STRING ),
'discriminator': STRING,
'*if': COND,
- '*features': FEATURES }
+ '*features': FEATURES,
+ '*aliases': ALIASES }
BRANCHES = { BRANCH, ... }
BRANCH = STRING : TYPE-REF
| STRING : { 'type': TYPE-REF, '*if': COND }
@@ -837,6 +840,34 @@ shows a conditional entity only when the condition is
satisfied in
this particular build.
+=== Aliases ===
+
+Object types, including structs and unions, can contain alias
+definitions.
+
+Aliases define alternative member names that may be used in the
+external representation to provide a value for a member in the same
+object or in a nested object.
+
+Syntax:
+ ALIAS = { '*alias': STRING,
+ 'source': [ STRING, ... ] }
+
+'source' is a list of member names representing the path to an object
+member, starting from the type where the alias definition is
+specified. It may refer to another alias name. It is allowed to use
+a path that doesn't necessarily match an existing member in every
+variant or even at all; in this case, the alias remains unused.
+
+If 'alias' is present, then the single member referred to by 'source'
+is made accessible with the name given in 'alias' in the type where
+the alias definition is specified.
+
+If 'alias' is not present, then all members in the object referred to
+by 'source' are made accessible in the type where the alias definition
+is specified with the same name as they have in 'source'.
+
+
=== Documentation comments ===
A multi-line comment that starts and ends with a '##' line is a
diff --git a/docs/sphinx/qapidoc.py b/docs/sphinx/qapidoc.py
index e03abcbb95..6c94c01148 100644
--- a/docs/sphinx/qapidoc.py
+++ b/docs/sphinx/qapidoc.py
@@ -310,7 +310,7 @@ class QAPISchemaGenRSTVisitor(QAPISchemaVisitor):
+ self._nodes_for_if_section(ifcond))
def visit_object_type(self, name, info, ifcond, features,
- base, members, variants):
+ base, members, variants, aliases):
doc = self._cur_doc
if base and base.is_implicit():
base = None
diff --git a/scripts/qapi/expr.py b/scripts/qapi/expr.py
index 2fcaaa2497..21fded529b 100644
--- a/scripts/qapi/expr.py
+++ b/scripts/qapi/expr.py
@@ -198,6 +198,32 @@ def check_features(features, info):
check_if(f, info, source)
+def check_aliases(aliases, info):
+ if aliases is None:
+ return
+ if not isinstance(aliases, list):
+ raise QAPISemError(info, "'aliases' must be an array")
+ for a in aliases:
+ if not isinstance(a, dict):
+ raise QAPISemError(info, "'aliases' entries must be objects")
+ check_keys(a, info, "alias", ['source'], ['alias'])
+
+ if 'alias' in a:
+ source = "alias member 'alias'"
+ check_name_is_str(a['alias'], info, source)
+ check_name_str(a['alias'], info, source)
+
+ if not isinstance(a['source'], list):
+ raise QAPISemError(info, "'source' must be an array")
+ if not a['source']:
+ raise QAPISemError(info, "'source' must not be empty")
+
+ source = "element of alias member 'source'"
+ for s in a['source']:
+ check_name_is_str(s, info, source)
+ check_name_str(s, info, source)
+
+
def check_enum(expr, info):
name = expr['enum']
members = expr['data']
@@ -228,6 +254,7 @@ def check_struct(expr, info):
check_type(members, info, "'data'", allow_dict=name)
check_type(expr.get('base'), info, "'base'")
+ check_aliases(expr.get('aliases'), info)
def check_union(expr, info):
@@ -245,6 +272,8 @@ def check_union(expr, info):
raise QAPISemError(info, "'discriminator' requires 'base'")
check_name_is_str(discriminator, info, "'discriminator'")
+ check_aliases(expr.get('aliases'), info)
+
for (key, value) in members.items():
source = "'data' member '%s'" % key
check_name_str(key, info, source)
@@ -331,7 +360,7 @@ def check_exprs(exprs):
elif meta == 'union':
check_keys(expr, info, meta,
['union', 'data'],
- ['base', 'discriminator', 'if', 'features'])
+ ['base', 'discriminator', 'if', 'features', 'aliases'])
normalize_members(expr.get('base'))
normalize_members(expr['data'])
check_union(expr, info)
@@ -342,7 +371,8 @@ def check_exprs(exprs):
check_alternate(expr, info)
elif meta == 'struct':
check_keys(expr, info, meta,
- ['struct', 'data'], ['base', 'if', 'features'])
+ ['struct', 'data'],
+ ['base', 'if', 'features', 'aliases'])
normalize_members(expr['data'])
check_struct(expr, info)
elif meta == 'command':
diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py
index 720449feee..5daa137163 100644
--- a/scripts/qapi/schema.py
+++ b/scripts/qapi/schema.py
@@ -117,7 +117,7 @@ class QAPISchemaVisitor:
pass
def visit_object_type(self, name, info, ifcond, features,
- base, members, variants):
+ base, members, variants, aliases):
pass
def visit_object_type_flat(self, name, info, ifcond, features,
@@ -331,9 +331,16 @@ class QAPISchemaArrayType(QAPISchemaType):
return "%s type ['%s']" % (self.meta, self._element_type_name)
+class QAPISchemaAlias:
+ def __init__(self, alias, source):
+ assert source
+ self.alias = alias
+ self.source = source
+
+
class QAPISchemaObjectType(QAPISchemaType):
def __init__(self, name, info, doc, ifcond, features,
- base, local_members, variants):
+ base, local_members, variants, aliases=None):
# struct has local_members, optional base, and no variants
# flat union has base, variants, and no local_members
# simple union has local_members, variants, and no base
@@ -351,6 +358,7 @@ class QAPISchemaObjectType(QAPISchemaType):
self.local_members = local_members
self.variants = variants
self.members = None
+ self.aliases = aliases or []
def check(self, schema):
# This calls another type T's .check() exactly when the C
@@ -443,7 +451,7 @@ class QAPISchemaObjectType(QAPISchemaType):
super().visit(visitor)
visitor.visit_object_type(
self.name, self.info, self.ifcond, self.features,
- self.base, self.local_members, self.variants)
+ self.base, self.local_members, self.variants, self.aliases)
visitor.visit_object_type_flat(
self.name, self.info, self.ifcond, self.features,
self.members, self.variants)
@@ -934,6 +942,12 @@ class QAPISchema:
return [QAPISchemaFeature(f['name'], info, f.get('if'))
for f in features]
+ def _make_aliases(self, aliases):
+ if aliases is None:
+ return []
+ return [QAPISchemaAlias(a.get('alias'), a['source'])
+ for a in aliases]
+
def _make_enum_members(self, values, info):
return [QAPISchemaEnumMember(v['name'], info, v.get('if'))
for v in values]
@@ -1008,11 +1022,12 @@ class QAPISchema:
base = expr.get('base')
data = expr['data']
ifcond = expr.get('if')
+ aliases = self._make_aliases(expr.get('aliases'))
features = self._make_features(expr.get('features'), info)
self._def_entity(QAPISchemaObjectType(
name, info, doc, ifcond, features, base,
self._make_members(data, info),
- None))
+ None, aliases))
def _make_variant(self, case, typ, ifcond, info):
return QAPISchemaVariant(case, info, typ, ifcond)
@@ -1031,6 +1046,7 @@ class QAPISchema:
data = expr['data']
base = expr.get('base')
ifcond = expr.get('if')
+ aliases = self._make_aliases(expr.get('aliases'))
features = self._make_features(expr.get('features'), info)
tag_name = expr.get('discriminator')
tag_member = None
@@ -1055,7 +1071,8 @@ class QAPISchema:
QAPISchemaObjectType(name, info, doc, ifcond, features,
base, members,
QAPISchemaVariants(
- tag_name, info, tag_member, variants)))
+ tag_name, info, tag_member, variants),
+ aliases))
def _def_alternate_type(self, expr, info, doc):
name = expr['alternate']
diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
index 2b4916cdaa..e870bebb7e 100644
--- a/scripts/qapi/types.py
+++ b/scripts/qapi/types.py
@@ -25,6 +25,7 @@ from .common import (
from .gen import QAPISchemaModularCVisitor, ifcontext
from .schema import (
QAPISchema,
+ QAPISchemaAlias,
QAPISchemaEnumMember,
QAPISchemaFeature,
QAPISchemaObjectType,
@@ -332,7 +333,8 @@ class QAPISchemaGenTypeVisitor(QAPISchemaModularCVisitor):
features: List[QAPISchemaFeature],
base: Optional[QAPISchemaObjectType],
members: List[QAPISchemaObjectTypeMember],
- variants: Optional[QAPISchemaVariants]) -> None:
+ variants: Optional[QAPISchemaVariants],
+ aliases: List[QAPISchemaAlias]) -> None:
# Nothing to do for the special empty builtin
if name == 'q_empty':
return
diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
index 339f152152..a35921ef2c 100644
--- a/scripts/qapi/visit.py
+++ b/scripts/qapi/visit.py
@@ -26,6 +26,7 @@ from .common import (
from .gen import QAPISchemaModularCVisitor, ifcontext
from .schema import (
QAPISchema,
+ QAPISchemaAlias,
QAPISchemaEnumMember,
QAPISchemaEnumType,
QAPISchemaFeature,
@@ -60,7 +61,8 @@ bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s
*obj, Error **errp);
def gen_visit_object_members(name: str,
base: Optional[QAPISchemaObjectType],
members: List[QAPISchemaObjectTypeMember],
- variants: Optional[QAPISchemaVariants]) -> str:
+ variants: Optional[QAPISchemaVariants],
+ aliases: List[QAPISchemaAlias]) -> str:
ret = mcgen('''
bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
@@ -68,6 +70,25 @@ bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s
*obj, Error **errp)
''',
c_name=c_name(name))
+ if aliases:
+ ret += mcgen('''
+ visit_start_alias_scope(v);
+''')
+
+ for a in aliases:
+ if a.alias:
+ alias = '"%s"' % a.alias
+ else:
+ alias = "NULL"
+
+ source_list = ", ".join('"%s"' % x for x in a.source)
+ source = "(const char * []) { %s, NULL }" % source_list
+
+ ret += mcgen('''
+ visit_define_alias(v, %(alias)s, %(source)s);
+''',
+ alias=alias, source=source)
+
if base:
ret += mcgen('''
if (!visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, errp)) {
@@ -133,6 +154,11 @@ bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s
*obj, Error **errp)
}
''')
+ if aliases:
+ ret += mcgen('''
+ visit_end_alias_scope(v);
+''')
+
ret += mcgen('''
return true;
}
@@ -361,14 +387,15 @@ class
QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
features: List[QAPISchemaFeature],
base: Optional[QAPISchemaObjectType],
members: List[QAPISchemaObjectTypeMember],
- variants: Optional[QAPISchemaVariants]) -> None:
+ variants: Optional[QAPISchemaVariants],
+ aliases: List[QAPISchemaAlias]) -> None:
# Nothing to do for the special empty builtin
if name == 'q_empty':
return
with ifcontext(ifcond, self._genh, self._genc):
self._genh.add(gen_visit_members_decl(name))
self._genc.add(gen_visit_object_members(name, base,
- members, variants))
+ members, variants,
aliases))
# TODO Worth changing the visitor signature, so we could
# directly use rather than repeat type.is_implicit()?
if not name.startswith('q_'):
diff --git a/tests/qapi-schema/test-qapi.py b/tests/qapi-schema/test-qapi.py
index e8db9d09d9..adf8bda89a 100755
--- a/tests/qapi-schema/test-qapi.py
+++ b/tests/qapi-schema/test-qapi.py
@@ -47,7 +47,7 @@ class QAPISchemaTestVisitor(QAPISchemaVisitor):
self._print_if(ifcond)
def visit_object_type(self, name, info, ifcond, features,
- base, members, variants):
+ base, members, variants, aliases):
print('object %s' % name)
if base:
print(' base %s' % base.name)
@@ -56,6 +56,11 @@ class QAPISchemaTestVisitor(QAPISchemaVisitor):
% (m.name, m.type.name, m.optional))
self._print_if(m.ifcond, 8)
self._print_features(m.features, indent=8)
+ for a in aliases:
+ if a.alias:
+ print(' alias %s -> %s' % (a.alias, '/'.join(a.source)))
+ else:
+ print(' alias * -> %s/*' % '/'.join(a.source))
self._print_variants(variants)
self._print_if(ifcond)
self._print_features(features)
diff --git a/tests/qapi-schema/double-type.err
b/tests/qapi-schema/double-type.err
index 71fc4dbb52..5d25d7623c 100644
--- a/tests/qapi-schema/double-type.err
+++ b/tests/qapi-schema/double-type.err
@@ -1,3 +1,3 @@
double-type.json: In struct 'bar':
double-type.json:2: struct has unknown key 'command'
-Valid keys are 'base', 'data', 'features', 'if', 'struct'.
+Valid keys are 'aliases', 'base', 'data', 'features', 'if', 'struct'.
diff --git a/tests/qapi-schema/unknown-expr-key.err
b/tests/qapi-schema/unknown-expr-key.err
index c5f395bf79..7429d1ff03 100644
--- a/tests/qapi-schema/unknown-expr-key.err
+++ b/tests/qapi-schema/unknown-expr-key.err
@@ -1,3 +1,3 @@
unknown-expr-key.json: In struct 'bar':
unknown-expr-key.json:2: struct has unknown keys 'bogus', 'phony'
-Valid keys are 'base', 'data', 'features', 'if', 'struct'.
+Valid keys are 'aliases', 'base', 'data', 'features', 'if', 'struct'.
--
2.28.0
[PATCH 6/6] tests/qapi-schema: Test cases for aliases, Kevin Wolf, 2020/11/12