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>

7 files changed, 54 insertions, 9 deletions

diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c
index dcfbf92faf..72c95ac7c1 100644
--- a/qapi/opts-visitor.c
+++ b/qapi/opts-visitor.c
@@ -513,6 +513,15 @@ opts_optional(Visitor *v, const char *name, bool *present)
 }
 
 
+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 @@ opts_visitor_new(const QemuOpts *opts)
      * 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 9391dea203..e39457bc79 100644
--- a/qapi/qapi-dealloc-visitor.c
+++ b/qapi/qapi-dealloc-visitor.c
@@ -107,17 +107,12 @@ static void qapi_dealloc_type_null(Visitor *v, const char *name, Error **errp)
 {
 }
 
-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 @@ QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
     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 dba11c66a7..5f68c251d2 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 e16b4b0725..41b7f87ddb 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -378,6 +378,13 @@ Visitor *qmp_input_get_visitor(QmpInputVisitor *v)
     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 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj, bool strict)
     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 dca893584d..5f0035cbf6 100644
--- a/qapi/qmp-output-visitor.c
+++ b/qapi/qmp-output-visitor.c
@@ -214,6 +214,13 @@ Visitor *qmp_output_get_visitor(QmpOutputVisitor *v)
     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 @@ QmpOutputVisitor *qmp_output_visitor_new(void)
     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 d7f3c2bd1e..6fb1229586 100644
--- a/qapi/string-input-visitor.c
+++ b/qapi/string-input-visitor.c
@@ -331,6 +331,13 @@ Visitor *string_input_get_visitor(StringInputVisitor *v)
     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 @@ StringInputVisitor *string_input_visitor_new(const char *str)
     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 bdc0fd0be4..ff9ddf068a 100644
--- a/qapi/string-output-visitor.c
+++ b/qapi/string-output-visitor.c
@@ -322,6 +322,13 @@ static void free_range(void *range, void *dummy)
     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 @@ StringOutputVisitor *string_output_visitor_new(bool human)
     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;
 }