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[PATCH v2 1/6] qapi: Add interfaces for alias support to Visitor
From: |
Kevin Wolf |
Subject: |
[PATCH v2 1/6] qapi: Add interfaces for alias support to Visitor |
Date: |
Thu, 11 Feb 2021 19:31:13 +0100 |
This adds functions to the Visitor interface that can be used to define
aliases and alias scopes.
Signed-off-by: Kevin Wolf <kwolf@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
- Re: [PATCH v2 6/6] tests/qapi-schema: Test cases for aliases, (continued)
[PATCH v2 3/6] qapi: Simplify full_name_nth() in qobject-input-visitor, Kevin Wolf, 2021/02/11
[PATCH v2 5/6] qapi: Add support for aliases, Kevin Wolf, 2021/02/11
[PATCH v2 1/6] qapi: Add interfaces for alias support to Visitor,
Kevin Wolf <=
Re: [PATCH v2 0/6] qapi: Add support for aliases, Markus Armbruster, 2021/02/24