This adds functions to the Visitor interface that can be used to define aliases and alias scopes.
Signed-off-by: Kevin Wolf <kw...@redhat.com> --- include/qapi/visitor-impl.h | 12 ++++++++++ include/qapi/visitor.h | 44 +++++++++++++++++++++++++++++++++++++ qapi/qapi-visit-core.c | 22 +++++++++++++++++++ 3 files changed, 78 insertions(+) diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h index 7362c043be..d9a6874528 100644 --- a/include/qapi/visitor-impl.h +++ b/include/qapi/visitor-impl.h @@ -113,6 +113,18 @@ struct Visitor The core takes care of the return type in the public interface. */ void (*optional)(Visitor *v, const char *name, bool *present); + /* + * Optional; intended for input visitors. If not given, aliases are + * ignored. + */ + void (*define_alias)(Visitor *v, const char *name, const char **source); + + /* Must be set if define_alias is set */ + void (*start_alias_scope)(Visitor *v); + + /* Must be set if define_alias is set */ + void (*end_alias_scope)(Visitor *v); + /* Must be set */ VisitorType type; diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h index ebc19ede7f..2ecbc20624 100644 --- a/include/qapi/visitor.h +++ b/include/qapi/visitor.h @@ -459,6 +459,50 @@ void visit_end_alternate(Visitor *v, void **obj); */ bool visit_optional(Visitor *v, const char *name, bool *present); +/* + * Defines a new alias rule. + * + * If @name is non-NULL, the member called @name in the external + * representation of the currently visited object is defined as an + * alias for the member described by @source. It is not allowed to + * call this function when the currently visited type is not an + * object. + * + * If @name is NULL, all members of the object described by @source + * are considered to have alias members with the same key in the + * currently visited object. + * + * @source is a NULL-terminated non-empty array of names that describe + * the path to a member, starting from the currently visited object. + * All elements in @source except the last one should describe + * objects. If an intermediate element refers to a member with a + * non-object type, the alias won't work (this case can legitimately + * happen in unions where an alias only makes sense for one branch, + * but not for another). + * + * The alias stays valid until the current alias scope ends. + * visit_start/end_struct() implicitly start/end an alias scope. + * Additionally, visit_start/end_alias_scope() can be used to explicitly + * create a nested alias scope. + */ +void visit_define_alias(Visitor *v, const char *name, const char **source); + +/* + * Begins an explicit alias scope. + * + * Alias definitions after here will only stay valid until the + * corresponding visit_end_alias_scope() is called. + */ +void visit_start_alias_scope(Visitor *v); + +/* + * Ends an explicit alias scope. + * + * Alias definitions between the correspoding visit_start_alias_scope() + * call and here go out of scope and won't apply in later code any more. + */ +void visit_end_alias_scope(Visitor *v); + /* * Visit an enum value. * diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c index 7e5f40e7f0..651dd88e02 100644 --- a/qapi/qapi-visit-core.c +++ b/qapi/qapi-visit-core.c @@ -135,6 +135,28 @@ bool visit_optional(Visitor *v, const char *name, bool *present) return *present; } +void visit_define_alias(Visitor *v, const char *name, const char **source) +{ + assert(source[0] != NULL); + if (v->define_alias) { + v->define_alias(v, name, source); + } +} + +void visit_start_alias_scope(Visitor *v) +{ + if (v->start_alias_scope) { + v->start_alias_scope(v); + } +} + +void visit_end_alias_scope(Visitor *v) +{ + if (v->end_alias_scope) { + v->end_alias_scope(v); + } +} + bool visit_is_input(Visitor *v) { return v->type == VISITOR_INPUT; -- 2.29.2