qapi: Add new visit_free() function
Making each visitor provide its own (awkwardly-named) FOO_cleanup()
is unusual, when we can instead have a polymorphic visit_free()
interface. Over the next few patches, we can use the polymorphic
functions to eliminate the need for a FOO_get_visitor() function
for accessing specific visitor functionality, once everything can
be accessed directly through the Visitor* interfaces.
The dealloc visitor is the first one converted to completely use
the new entry point, since qapi_dealloc_visitor_cleanup() was the
only reason that qapi_dealloc_get_visitor() existed, and only
generated and testsuite code was even using it. With the new
visit_free() entry point in place, we no longer need to expose
the QapiDeallocVisitor subtype through qapi_dealloc_visitor_new(),
and can get by with less generated code, with diffs that look like:
| void qapi_free_ACPIOSTInfo(ACPIOSTInfo *obj)
| {
|- QapiDeallocVisitor *qdv;
| Visitor *v;
|
| if (!obj) {
| return;
| }
|
|- qdv = qapi_dealloc_visitor_new();
|- v = qapi_dealloc_get_visitor(qdv);
|+ v = qapi_dealloc_visitor_new();
| visit_type_ACPIOSTInfo(v, NULL, &obj, NULL);
|- qapi_dealloc_visitor_cleanup(qdv);
|+ visit_free(v);
|}
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1465490926-28625-5-git-send-email-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index 0ae239a..db9d5b6 100644
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -802,32 +802,28 @@
void qapi_free_UserDefOne(UserDefOne *obj)
{
- QapiDeallocVisitor *qdv;
Visitor *v;
if (!obj) {
return;
}
- qdv = qapi_dealloc_visitor_new();
- v = qapi_dealloc_get_visitor(qdv);
+ v = qapi_dealloc_visitor_new();
visit_type_UserDefOne(v, NULL, &obj, NULL);
- qapi_dealloc_visitor_cleanup(qdv);
+ visit_free(v);
}
void qapi_free_UserDefOneList(UserDefOneList *obj)
{
- QapiDeallocVisitor *qdv;
Visitor *v;
if (!obj) {
return;
}
- qdv = qapi_dealloc_visitor_new();
- v = qapi_dealloc_get_visitor(qdv);
+ v = qapi_dealloc_visitor_new();
visit_type_UserDefOneList(v, NULL, &obj, NULL);
- qapi_dealloc_visitor_cleanup(qdv);
+ visit_free(v);
}
=== scripts/qapi-visit.py ===
@@ -985,7 +981,6 @@
{
Error *err = NULL;
QmpOutputVisitor *qov = qmp_output_visitor_new();
- QapiDeallocVisitor *qdv;
Visitor *v;
v = qmp_output_get_visitor(qov);
@@ -997,11 +992,10 @@
out:
error_propagate(errp, err);
- qmp_output_visitor_cleanup(qov);
- qdv = qapi_dealloc_visitor_new();
- v = qapi_dealloc_get_visitor(qdv);
+ visit_free(v);
+ v = qapi_dealloc_visitor_new();
visit_type_UserDefOne(v, "unused", &ret_in, NULL);
- qapi_dealloc_visitor_cleanup(qdv);
+ visit_free(v);
}
static void qmp_marshal_my_command(QDict *args, QObject **ret, Error **errp)
@@ -1009,7 +1003,6 @@
Error *err = NULL;
UserDefOne *retval;
QmpInputVisitor *qiv = qmp_input_visitor_new(QOBJECT(args), true);
- QapiDeallocVisitor *qdv;
Visitor *v;
UserDefOneList *arg1 = NULL;
@@ -1036,13 +1029,12 @@
out:
error_propagate(errp, err);
- qmp_input_visitor_cleanup(qiv);
- qdv = qapi_dealloc_visitor_new();
- v = qapi_dealloc_get_visitor(qdv);
+ visit_free(v);
+ v = qapi_dealloc_visitor_new();
visit_start_struct(v, NULL, NULL, 0, NULL);
visit_type_UserDefOneList(v, "arg1", &arg1, NULL);
visit_end_struct(v, NULL);
- qapi_dealloc_visitor_cleanup(qdv);
+ visit_free(v);
}
static void qmp_init_marshal(void)
diff --git a/include/qapi/dealloc-visitor.h b/include/qapi/dealloc-visitor.h
index 45b06b2..b3e5c85 100644
--- a/include/qapi/dealloc-visitor.h
+++ b/include/qapi/dealloc-visitor.h
@@ -23,9 +23,6 @@
* qapi_free_FOO() functions, and is the only visitor designed to work
* correctly in the face of a partially-constructed QAPI tree.
*/
-QapiDeallocVisitor *qapi_dealloc_visitor_new(void);
-void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *d);
-
-Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v);
+Visitor *qapi_dealloc_visitor_new(void);
#endif
diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h
index a495bf0..525b068 100644
--- a/include/qapi/visitor-impl.h
+++ b/include/qapi/visitor-impl.h
@@ -104,6 +104,9 @@
/* Must be set */
VisitorType type;
+
+ /* Must be set */
+ void (*free)(Visitor *v);
};
#endif
diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h
index 25d0cc2..2ded852 100644
--- a/include/qapi/visitor.h
+++ b/include/qapi/visitor.h
@@ -37,6 +37,24 @@
* implemented by each visitor, and docs/qapi-code-gen.txt for more
* about the QAPI code generator.
*
+ * All of the visitors are created via:
+ *
+ * Type *subtype_visitor_new(parameters...);
+ *
+ * where Type is either directly 'Visitor *', or is a subtype that can
+ * be trivially upcast to Visitor * via another function:
+ *
+ * Visitor *subtype_get_visitor(SubtypeVisitor *);
+ *
+ * A visitor should be used for exactly one top-level visit_type_FOO()
+ * or virtual walk, then passed to visit_free() to clean up resources.
+ * It is okay to free the visitor without completing the visit, if
+ * some other error is detected in the meantime. Output visitors
+ * provide an additional function, for collecting the final results of
+ * a successful visit: string_output_get_string() and
+ * qmp_output_get_qobject(); this collection function should not be
+ * called if any errors were reported during the visit.
+ *
* All QAPI types have a corresponding function with a signature
* roughly compatible with this:
*
@@ -222,6 +240,19 @@
char padding[];
} GenericAlternate;
+/*** Visitor cleanup ***/
+
+/*
+ * Free @v and any resources it has tied up.
+ *
+ * May be called whether or not the visit has been successfully
+ * completed, but should not be called until a top-level
+ * visit_type_FOO() or visit_start_ITEM() has been performed on the
+ * visitor. Safe if @v is NULL.
+ */
+void visit_free(Visitor *v);
+
+
/*** Visiting structures ***/
/*
@@ -272,7 +303,7 @@
* Must be called after any successful use of visit_start_struct(),
* even if intermediate processing was skipped due to errors, to allow
* the backend to release any resources. Destroying the visitor early
- * behaves as if this was implicitly called.
+ * with visit_free() behaves as if this was implicitly called.
*/
void visit_end_struct(Visitor *v, void **obj);
@@ -332,7 +363,7 @@
* Must be called after any successful use of visit_start_list(), even
* if intermediate processing was skipped due to errors, to allow the
* backend to release any resources. Destroying the visitor early
- * behaves as if this was implicitly called.
+ * with visit_free() behaves as if this was implicitly called.
*/
void visit_end_list(Visitor *v, void **list);
@@ -368,7 +399,7 @@
* Must be called after any successful use of visit_start_alternate(),
* even if intermediate processing was skipped due to errors, to allow
* the backend to release any resources. Destroying the visitor early
- * behaves as if this was implicitly called.
+ * with visit_free() behaves as if this was implicitly called.
*
*/
void visit_end_alternate(Visitor *v, void **obj);
diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c
index dcfbf92..72c95ac 100644
--- a/qapi/opts-visitor.c
+++ b/qapi/opts-visitor.c
@@ -513,6 +513,15 @@
}
+static void
+opts_free(Visitor *v)
+{
+ OptsVisitor *ov = to_ov(v);
+
+ opts_visitor_cleanup(ov);
+}
+
+
OptsVisitor *
opts_visitor_new(const QemuOpts *opts)
{
@@ -540,6 +549,7 @@
* skip some mandatory methods... */
ov->visitor.optional = &opts_optional;
+ ov->visitor.free = opts_free;
ov->opts_root = opts;
diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c
index 9391dea..e39457b 100644
--- a/qapi/qapi-dealloc-visitor.c
+++ b/qapi/qapi-dealloc-visitor.c
@@ -107,17 +107,12 @@
{
}
-Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v)
+static void qapi_dealloc_free(Visitor *v)
{
- return &v->visitor;
+ g_free(container_of(v, QapiDeallocVisitor, visitor));
}
-void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *v)
-{
- g_free(v);
-}
-
-QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
+Visitor *qapi_dealloc_visitor_new(void)
{
QapiDeallocVisitor *v;
@@ -138,6 +133,7 @@
v->visitor.type_number = qapi_dealloc_type_number;
v->visitor.type_any = qapi_dealloc_type_anything;
v->visitor.type_null = qapi_dealloc_type_null;
+ v->visitor.free = qapi_dealloc_free;
- return v;
+ return &v->visitor;
}
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index dba11c6..5f68c25 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -20,6 +20,13 @@
#include "qapi/visitor.h"
#include "qapi/visitor-impl.h"
+void visit_free(Visitor *v)
+{
+ if (v) {
+ v->free(v);
+ }
+}
+
void visit_start_struct(Visitor *v, const char *name, void **obj,
size_t size, Error **errp)
{
diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index e16b4b0..41b7f87 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -378,6 +378,13 @@
return &v->visitor;
}
+static void qmp_input_free(Visitor *v)
+{
+ QmpInputVisitor *qiv = to_qiv(v);
+
+ qmp_input_visitor_cleanup(qiv);
+}
+
void qmp_input_visitor_cleanup(QmpInputVisitor *v)
{
qobject_decref(v->root);
@@ -406,6 +413,7 @@
v->visitor.type_any = qmp_input_type_any;
v->visitor.type_null = qmp_input_type_null;
v->visitor.optional = qmp_input_optional;
+ v->visitor.free = qmp_input_free;
v->strict = strict;
v->root = obj;
diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c
index dca8935..5f0035c 100644
--- a/qapi/qmp-output-visitor.c
+++ b/qapi/qmp-output-visitor.c
@@ -214,6 +214,13 @@
return &v->visitor;
}
+static void qmp_output_free(Visitor *v)
+{
+ QmpOutputVisitor *qov = to_qov(v);
+
+ qmp_output_visitor_cleanup(qov);
+}
+
void qmp_output_visitor_cleanup(QmpOutputVisitor *v)
{
QStackEntry *e, *tmp;
@@ -246,6 +253,7 @@
v->visitor.type_number = qmp_output_type_number;
v->visitor.type_any = qmp_output_type_any;
v->visitor.type_null = qmp_output_type_null;
+ v->visitor.free = qmp_output_free;
QTAILQ_INIT(&v->stack);
diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c
index d7f3c2b..6fb1229 100644
--- a/qapi/string-input-visitor.c
+++ b/qapi/string-input-visitor.c
@@ -331,6 +331,13 @@
return &v->visitor;
}
+static void string_input_free(Visitor *v)
+{
+ StringInputVisitor *siv = to_siv(v);
+
+ string_input_visitor_cleanup(siv);
+}
+
void string_input_visitor_cleanup(StringInputVisitor *v)
{
g_list_foreach(v->ranges, free_range, NULL);
@@ -355,6 +362,7 @@
v->visitor.next_list = next_list;
v->visitor.end_list = end_list;
v->visitor.optional = parse_optional;
+ v->visitor.free = string_input_free;
v->string = str;
return v;
diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c
index bdc0fd0..ff9ddf0 100644
--- a/qapi/string-output-visitor.c
+++ b/qapi/string-output-visitor.c
@@ -322,6 +322,13 @@
g_free(range);
}
+static void string_output_free(Visitor *v)
+{
+ StringOutputVisitor *sov = to_sov(v);
+
+ string_output_visitor_cleanup(sov);
+}
+
void string_output_visitor_cleanup(StringOutputVisitor *sov)
{
if (sov->string) {
@@ -351,6 +358,7 @@
v->visitor.start_list = start_list;
v->visitor.next_list = next_list;
v->visitor.end_list = end_list;
+ v->visitor.free = string_output_free;
return v;
}
diff --git a/scripts/qapi-commands.py b/scripts/qapi-commands.py
index 971dc4e..77ecd47 100644
--- a/scripts/qapi-commands.py
+++ b/scripts/qapi-commands.py
@@ -62,7 +62,6 @@
{
Error *err = NULL;
QmpOutputVisitor *qov = qmp_output_visitor_new();
- QapiDeallocVisitor *qdv;
Visitor *v;
v = qmp_output_get_visitor(qov);
@@ -74,11 +73,10 @@
out:
error_propagate(errp, err);
- qmp_output_visitor_cleanup(qov);
- qdv = qapi_dealloc_visitor_new();
- v = qapi_dealloc_get_visitor(qdv);
+ visit_free(v);
+ v = qapi_dealloc_visitor_new();
visit_type_%(c_name)s(v, "unused", &ret_in, NULL);
- qapi_dealloc_visitor_cleanup(qdv);
+ visit_free(v);
}
''',
c_type=ret_type.c_type(), c_name=ret_type.c_name())
@@ -116,7 +114,6 @@
if arg_type and arg_type.members:
ret += mcgen('''
QmpInputVisitor *qiv = qmp_input_visitor_new(QOBJECT(args), true);
- QapiDeallocVisitor *qdv;
Visitor *v;
%(c_name)s arg = {0};
@@ -155,13 +152,12 @@
''')
if arg_type and arg_type.members:
ret += mcgen('''
- qmp_input_visitor_cleanup(qiv);
- qdv = qapi_dealloc_visitor_new();
- v = qapi_dealloc_get_visitor(qdv);
+ visit_free(v);
+ v = qapi_dealloc_visitor_new();
visit_start_struct(v, NULL, NULL, 0, NULL);
visit_type_%(c_name)s_members(v, &arg, NULL);
visit_end_struct(v, NULL);
- qapi_dealloc_visitor_cleanup(qdv);
+ visit_free(v);
''',
c_name=arg_type.c_name())
diff --git a/scripts/qapi-event.py b/scripts/qapi-event.py
index 084c40a..909e8d6 100644
--- a/scripts/qapi-event.py
+++ b/scripts/qapi-event.py
@@ -119,7 +119,7 @@
if arg_type and arg_type.members:
ret += mcgen('''
out:
- qmp_output_visitor_cleanup(qov);
+ visit_free(v);
''')
ret += mcgen('''
error_propagate(errp, err);
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index 437cf6c..5ace2cf 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -150,17 +150,15 @@
void qapi_free_%(c_name)s(%(c_name)s *obj)
{
- QapiDeallocVisitor *qdv;
Visitor *v;
if (!obj) {
return;
}
- qdv = qapi_dealloc_visitor_new();
- v = qapi_dealloc_get_visitor(qdv);
+ v = qapi_dealloc_visitor_new();
visit_type_%(c_name)s(v, NULL, &obj, NULL);
- qapi_dealloc_visitor_cleanup(qdv);
+ visit_free(v);
}
''',
c_name=c_name(name))
diff --git a/tests/test-visitor-serialization.c b/tests/test-visitor-serialization.c
index db781c0..bcbfd2a 100644
--- a/tests/test-visitor-serialization.c
+++ b/tests/test-visitor-serialization.c
@@ -89,11 +89,11 @@
static void dealloc_helper(void *native_in, VisitorFunc visit, Error **errp)
{
- QapiDeallocVisitor *qdv = qapi_dealloc_visitor_new();
+ Visitor *v = qapi_dealloc_visitor_new();
- visit(qapi_dealloc_get_visitor(qdv), &native_in, errp);
+ visit(v, &native_in, errp);
- qapi_dealloc_visitor_cleanup(qdv);
+ visit_free(v);
}
static void visit_primitive_type(Visitor *v, void **native, Error **errp)
