@@ -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 @@ typedef struct GenericAlternate {
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 @@ void visit_check_struct(Visitor *v, Error **errp);
* 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 @@ GenericList *visit_next_list(Visitor *v, GenericList *tail, size_t size);
* 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 @@ void visit_start_alternate(Visitor *v, const char *name,
* 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);
@@ -104,6 +104,9 @@ struct Visitor
/* Must be set */
VisitorType type;
+
+ /* Must be set */
+ void (*free)(Visitor *v);
};
#endif
@@ -62,7 +62,6 @@ static void qmp_marshal_output_%(c_name)s(%(c_type)s ret_in, QObject **ret_out,
{
Error *err = NULL;
QmpOutputVisitor *qov = qmp_output_visitor_new();
- QapiDeallocVisitor *qdv;
Visitor *v;
v = qmp_output_get_visitor(qov);
@@ -74,11 +73,10 @@ static void qmp_marshal_output_%(c_name)s(%(c_type)s ret_in, QObject **ret_out,
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 @@ def gen_marshal(name, arg_type, ret_type):
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 @@ out:
''')
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())
@@ -119,7 +119,7 @@ def gen_event_send(name, arg_type):
if arg_type and arg_type.members:
ret += mcgen('''
out:
- qmp_output_visitor_cleanup(qov);
+ visit_free(v);
''')
ret += mcgen('''
error_propagate(errp, err);
@@ -150,17 +150,15 @@ def gen_type_cleanup(name):
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))
@@ -23,9 +23,6 @@ typedef struct QapiDeallocVisitor QapiDeallocVisitor;
* 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
@@ -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)
{
@@ -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;
@@ -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;
}
@@ -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;
@@ -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);
@@ -335,6 +335,13 @@ 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);
@@ -359,6 +366,7 @@ 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;
@@ -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;
}
@@ -89,11 +89,11 @@ typedef void (*VisitorFunc)(Visitor *v, void **native, Error **errp);
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)
@@ -802,32 +802,28 @@ Example:
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 @@ Example:
{
Error *err = NULL;
QmpOutputVisitor *qov = qmp_output_visitor_new();
- QapiDeallocVisitor *qdv;
Visitor *v;
v = qmp_output_get_visitor(qov);
@@ -997,11 +992,10 @@ Example:
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 @@ Example:
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 @@ Example:
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)
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> --- v5: improve commit message, avoid sensitivity on dealloc struct layout, blank lines after declarations v4: new patch, inspired by review of v3 7/18 --- include/qapi/visitor.h | 37 ++++++++++++++++++++++++++++++++++--- include/qapi/visitor-impl.h | 3 +++ scripts/qapi-commands.py | 16 ++++++---------- scripts/qapi-event.py | 2 +- scripts/qapi-types.py | 6 ++---- include/qapi/dealloc-visitor.h | 5 +---- qapi/qapi-visit-core.c | 7 +++++++ qapi/opts-visitor.c | 10 ++++++++++ qapi/qapi-dealloc-visitor.c | 14 +++++--------- qapi/qmp-input-visitor.c | 8 ++++++++ qapi/qmp-output-visitor.c | 8 ++++++++ qapi/string-input-visitor.c | 8 ++++++++ qapi/string-output-visitor.c | 8 ++++++++ tests/test-visitor-serialization.c | 6 +++--- docs/qapi-code-gen.txt | 28 ++++++++++------------------ 15 files changed, 114 insertions(+), 52 deletions(-)