[Updated commit message:]
Our existing input visitors were not very consistent on errors
in a function taking 'TYPE **obj' (that is, start_struct(),
start_alternate(), type_str(), and type_any(). next_list() is
similar, except that since commit 08f9541, it can't fail).
While all of them set '*obj' to allocated storage on success,
it was not obvious whether '*obj' was guaranteed safe on failure,
or whether it was left uninitialized. But a future patch wants
to guarantee that visit_type_FOO() does not leak a partially-
constructed obj back to the caller; it is easier to implement
this if we can reliably state that input visitors assign '*obj'
regardless of success or failure, and that on failure *obj is
NULL. Add assertions to enforce consistency in the final
setting of err vs. *obj.
The opts-visitor start_struct() doesn't set an error, but it
also was doing a weird check for 0 size; all callers pass in
non-zero size if obj is non-NULL.
The testsuite has at least one spot where we no longer need
to pre-initialize a variable prior to a visit; valgrind confirms
that the test is still fine with the cleanup.
A later patch will document the design constraint implemented
here.
Signed-off-by: Eric Blake <ebl...@redhat.com>
---
v15: enhance commit message, hoist assertions from later in series
v14: no change
v13: no change
v12: new patch
---
qapi/qapi-visit-core.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c
index 3a131ce..7ad5ff4 100644
--- a/qapi/qapi-visit-core.c
+++ b/qapi/qapi-visit-core.c
@@ -27,7 +27,7 @@ void visit_start_struct(Visitor *v, const char *name, void
**obj,
v->start_struct(v, name, obj, size, &err);
if (obj && v->type == VISITOR_INPUT) {
- assert(err || *obj);
+ assert(!err != !*obj);
}
error_propagate(errp, err);
}
@@ -62,11 +62,11 @@ void visit_start_alternate(Visitor *v, const char *name,
assert(obj && size >= sizeof(GenericAlternate));
if (v->start_alternate) {
v->start_alternate(v, name, obj, size, promote_int, &err);
- if (v->type == VISITOR_INPUT) {
- assert(err || *obj);
- }
- error_propagate(errp, err);
}
+ if (v->type == VISITOR_INPUT) {
+ assert(!err != !*obj);
+ }
+ error_propagate(errp, err);
}
void visit_end_alternate(Visitor *v)
@@ -205,7 +205,7 @@ void visit_type_str(Visitor *v, const char *name, char
**obj, Error **errp)
assert(obj);
v->type_str(v, name, obj, &err);
if (v->type == VISITOR_INPUT) {
- assert(err || *obj);
+ assert(!err != !*obj);
}
error_propagate(errp, err);
}
@@ -223,7 +223,7 @@ void visit_type_any(Visitor *v, const char *name, QObject
**obj, Error **errp)
assert(obj);
v->type_any(v, name, obj, &err);
if (v->type == VISITOR_INPUT) {
- assert(err || *obj);
+ assert(!err != !*obj);
}
error_propagate(errp, err);
}
--
2.5.5
