Message ID | 20210211183118.422036-3-kwolf@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | qapi: Add support for aliases | expand |
Kevin Wolf <kwolf@redhat.com> writes: > This makes qobject-input-visitor remember the currently valid aliases in > each StackObject. It doesn't actually allow using the aliases yet. > > Signed-off-by: Kevin Wolf <kwolf@redhat.com> > --- > qapi/qobject-input-visitor.c | 145 +++++++++++++++++++++++++++++++++++ > 1 file changed, 145 insertions(+) > > diff --git a/qapi/qobject-input-visitor.c b/qapi/qobject-input-visitor.c > index 23843b242e..aa95cd49bd 100644 > --- a/qapi/qobject-input-visitor.c > +++ b/qapi/qobject-input-visitor.c > @@ -29,6 +29,50 @@ > #include "qemu/cutils.h" > #include "qemu/option.h" > > +/* > + * Describes an alias that is relevant for the current StackObject, > + * either because it aliases a member of the currently visited object > + * or because it aliases a member of a nested object. > + * > + * When processing a nested object, all InputVisitorAlias objects that > + * are relevant for the nested object are propagated, i.e. copied with > + * the name of the nested object removed from @source. > + */ > +typedef struct InputVisitorAlias { > + /* StackObject in which the alias was defined */ > + struct StackObject *alias_so; > + > + /* > + * Alias name as defined for @alias_so. > + * NULL means that this is a wildcard alias, i.e. all members of > + * @src get an alias in @alias_so with the same name. > + */ > + const char *name; > + > + /* > + * NULL terminated array representing a path to the source member NULL-terminated > + * that the alias refers to. > + * > + * Must contain at least one non-NULL element if @alias is not NULL. > + * > + * If it contains no non-NULL element, @alias_so must be different > + * from the StackObject which contains this InputVisitorAlias in > + * its aliases list. In this case, all elements in the currently > + * visited object have an alias with the same name in @alias_so. > + */ > + const char **src; > + > + /* > + * The alias remains valid as long as the StackObject which > + * contains this InputVisitorAlias in its aliases list has > + * StackObject.alias_scope_nesting >= InputVisitorAlias.scope_nesting > + * or until the whole StackObject is removed. > + */ > + int scope_nesting; > + > + QSLIST_ENTRY(InputVisitorAlias) next; > +} InputVisitorAlias; > + > typedef struct StackObject { > const char *name; /* Name of @obj in its parent, if any */ > QObject *obj; /* QDict or QList being visited */ > @@ -38,6 +82,9 @@ typedef struct StackObject { > const QListEntry *entry; /* If @obj is QList: unvisited tail */ > unsigned index; /* If @obj is QList: list index of @entry */ > > + QSLIST_HEAD(, InputVisitorAlias) aliases; > + int alias_scope_nesting; /* Number of open alias scopes */ > + > QSLIST_ENTRY(StackObject) node; /* parent */ > } StackObject; > > @@ -203,6 +250,43 @@ static const char *qobject_input_get_keyval(QObjectInputVisitor *qiv, > return qstring_get_str(qstr); > } > > +/* > + * Propagate aliases from the parent StackObject @src to its direct > + * child StackObject @dst, which is representing the child struct @name. > + * > + * Every alias whose source path begins with @dst->name and which still > + * applies in @dst (i.e. it is either a wildcard alias or has at least > + * one more source path element) is propagated to @dst with the first > + * element (i.e. @dst->name) removed from the source path. > + */ > +static void propagate_aliases(StackObject *dst, StackObject *src) > +{ > + InputVisitorAlias *a; > + > + QSLIST_FOREACH(a, &src->aliases, next) { > + if (!a->src[0] || strcmp(a->src[0], dst->name)) { > + continue; > + } > + > + /* > + * If this is not a wildcard alias, but a->src[1] is NULL, > + * then it referred to dst->name in src and doesn't apply > + * inside dst any more. > + */ > + if (a->src[1] || !a->name) { The comment explains "if COND then there is nothing to do". The code that follows it does "if (!COND) { do stuff }". Works, but I had to stop and re-read to get it. How do you like if (a->name && !a->src[1]) { continue; } do stuff ? > + InputVisitorAlias *alias = g_new(InputVisitorAlias, 1); > + > + *alias = (InputVisitorAlias) { > + .name = a->name, > + .alias_so = a->alias_so, > + .src = &a->src[1], > + }; > + > + QSLIST_INSERT_HEAD(&dst->aliases, alias, next); > + } > + } > +} > + > static const QListEntry *qobject_input_push(QObjectInputVisitor *qiv, > const char *name, > QObject *obj, void *qapi) > @@ -226,6 +310,9 @@ static const QListEntry *qobject_input_push(QObjectInputVisitor *qiv, > g_hash_table_insert(h, (void *)qdict_entry_key(entry), NULL); > } > tos->h = h; > + if (!QSLIST_EMPTY(&qiv->stack)) { > + propagate_aliases(tos, QSLIST_FIRST(&qiv->stack)); > + } > } else { > assert(qlist); > tos->entry = qlist_first(qlist); > @@ -257,10 +344,17 @@ static bool qobject_input_check_struct(Visitor *v, Error **errp) > > static void qobject_input_stack_object_free(StackObject *tos) > { > + InputVisitorAlias *a; > + > if (tos->h) { > g_hash_table_unref(tos->h); > } > > + while ((a = QSLIST_FIRST(&tos->aliases))) { > + QSLIST_REMOVE_HEAD(&tos->aliases, next); > + g_free(a); > + } > + > g_free(tos); > } > > @@ -274,6 +368,54 @@ static void qobject_input_pop(Visitor *v, void **obj) > qobject_input_stack_object_free(tos); > } > > +static void qobject_input_start_alias_scope(Visitor *v) > +{ > + QObjectInputVisitor *qiv = to_qiv(v); > + StackObject *tos = QSLIST_FIRST(&qiv->stack); > + > + tos->alias_scope_nesting++; > +} > + > +static void qobject_input_end_alias_scope(Visitor *v) > +{ > + QObjectInputVisitor *qiv = to_qiv(v); > + StackObject *tos = QSLIST_FIRST(&qiv->stack); > + InputVisitorAlias *a, *next; > + > + assert(tos->alias_scope_nesting > 0); > + tos->alias_scope_nesting--; > + > + QSLIST_FOREACH_SAFE(a, &tos->aliases, next, next) { > + if (a->scope_nesting > tos->alias_scope_nesting) { > + QSLIST_REMOVE(&tos->aliases, a, InputVisitorAlias, next); > + g_free(a); > + } > + } > +} > + > +static void qobject_input_define_alias(Visitor *v, const char *name, > + const char **source) > +{ > + QObjectInputVisitor *qiv = to_qiv(v); > + StackObject *tos = QSLIST_FIRST(&qiv->stack); > + InputVisitorAlias *alias = g_new(InputVisitorAlias, 1); > + > + /* > + * The source path can become empty during alias propagation for > + * wildcard aliases, but not when defining an alias (it would map > + * all names onto themselves, which doesn't make sense). > + */ > + assert(source[0]); > + > + *alias = (InputVisitorAlias) { > + .name = name, > + .alias_so = tos, > + .src = source, > + }; > + > + QSLIST_INSERT_HEAD(&tos->aliases, alias, next); > +} > + > static bool qobject_input_start_struct(Visitor *v, const char *name, void **obj, > size_t size, Error **errp) > { > @@ -696,6 +838,9 @@ static QObjectInputVisitor *qobject_input_visitor_base_new(QObject *obj) > v->visitor.end_list = qobject_input_end_list; > v->visitor.start_alternate = qobject_input_start_alternate; > v->visitor.optional = qobject_input_optional; > + v->visitor.define_alias = qobject_input_define_alias; > + v->visitor.start_alias_scope = qobject_input_start_alias_scope; > + v->visitor.end_alias_scope = qobject_input_end_alias_scope; > v->visitor.free = qobject_input_free; > > v->root = qobject_ref(obj);
diff --git a/qapi/qobject-input-visitor.c b/qapi/qobject-input-visitor.c index 23843b242e..aa95cd49bd 100644 --- a/qapi/qobject-input-visitor.c +++ b/qapi/qobject-input-visitor.c @@ -29,6 +29,50 @@ #include "qemu/cutils.h" #include "qemu/option.h" +/* + * Describes an alias that is relevant for the current StackObject, + * either because it aliases a member of the currently visited object + * or because it aliases a member of a nested object. + * + * When processing a nested object, all InputVisitorAlias objects that + * are relevant for the nested object are propagated, i.e. copied with + * the name of the nested object removed from @source. + */ +typedef struct InputVisitorAlias { + /* StackObject in which the alias was defined */ + struct StackObject *alias_so; + + /* + * Alias name as defined for @alias_so. + * NULL means that this is a wildcard alias, i.e. all members of + * @src get an alias in @alias_so with the same name. + */ + const char *name; + + /* + * NULL terminated array representing a path to the source member + * that the alias refers to. + * + * Must contain at least one non-NULL element if @alias is not NULL. + * + * If it contains no non-NULL element, @alias_so must be different + * from the StackObject which contains this InputVisitorAlias in + * its aliases list. In this case, all elements in the currently + * visited object have an alias with the same name in @alias_so. + */ + const char **src; + + /* + * The alias remains valid as long as the StackObject which + * contains this InputVisitorAlias in its aliases list has + * StackObject.alias_scope_nesting >= InputVisitorAlias.scope_nesting + * or until the whole StackObject is removed. + */ + int scope_nesting; + + QSLIST_ENTRY(InputVisitorAlias) next; +} InputVisitorAlias; + typedef struct StackObject { const char *name; /* Name of @obj in its parent, if any */ QObject *obj; /* QDict or QList being visited */ @@ -38,6 +82,9 @@ typedef struct StackObject { const QListEntry *entry; /* If @obj is QList: unvisited tail */ unsigned index; /* If @obj is QList: list index of @entry */ + QSLIST_HEAD(, InputVisitorAlias) aliases; + int alias_scope_nesting; /* Number of open alias scopes */ + QSLIST_ENTRY(StackObject) node; /* parent */ } StackObject; @@ -203,6 +250,43 @@ static const char *qobject_input_get_keyval(QObjectInputVisitor *qiv, return qstring_get_str(qstr); } +/* + * Propagate aliases from the parent StackObject @src to its direct + * child StackObject @dst, which is representing the child struct @name. + * + * Every alias whose source path begins with @dst->name and which still + * applies in @dst (i.e. it is either a wildcard alias or has at least + * one more source path element) is propagated to @dst with the first + * element (i.e. @dst->name) removed from the source path. + */ +static void propagate_aliases(StackObject *dst, StackObject *src) +{ + InputVisitorAlias *a; + + QSLIST_FOREACH(a, &src->aliases, next) { + if (!a->src[0] || strcmp(a->src[0], dst->name)) { + continue; + } + + /* + * If this is not a wildcard alias, but a->src[1] is NULL, + * then it referred to dst->name in src and doesn't apply + * inside dst any more. + */ + if (a->src[1] || !a->name) { + InputVisitorAlias *alias = g_new(InputVisitorAlias, 1); + + *alias = (InputVisitorAlias) { + .name = a->name, + .alias_so = a->alias_so, + .src = &a->src[1], + }; + + QSLIST_INSERT_HEAD(&dst->aliases, alias, next); + } + } +} + static const QListEntry *qobject_input_push(QObjectInputVisitor *qiv, const char *name, QObject *obj, void *qapi) @@ -226,6 +310,9 @@ static const QListEntry *qobject_input_push(QObjectInputVisitor *qiv, g_hash_table_insert(h, (void *)qdict_entry_key(entry), NULL); } tos->h = h; + if (!QSLIST_EMPTY(&qiv->stack)) { + propagate_aliases(tos, QSLIST_FIRST(&qiv->stack)); + } } else { assert(qlist); tos->entry = qlist_first(qlist); @@ -257,10 +344,17 @@ static bool qobject_input_check_struct(Visitor *v, Error **errp) static void qobject_input_stack_object_free(StackObject *tos) { + InputVisitorAlias *a; + if (tos->h) { g_hash_table_unref(tos->h); } + while ((a = QSLIST_FIRST(&tos->aliases))) { + QSLIST_REMOVE_HEAD(&tos->aliases, next); + g_free(a); + } + g_free(tos); } @@ -274,6 +368,54 @@ static void qobject_input_pop(Visitor *v, void **obj) qobject_input_stack_object_free(tos); } +static void qobject_input_start_alias_scope(Visitor *v) +{ + QObjectInputVisitor *qiv = to_qiv(v); + StackObject *tos = QSLIST_FIRST(&qiv->stack); + + tos->alias_scope_nesting++; +} + +static void qobject_input_end_alias_scope(Visitor *v) +{ + QObjectInputVisitor *qiv = to_qiv(v); + StackObject *tos = QSLIST_FIRST(&qiv->stack); + InputVisitorAlias *a, *next; + + assert(tos->alias_scope_nesting > 0); + tos->alias_scope_nesting--; + + QSLIST_FOREACH_SAFE(a, &tos->aliases, next, next) { + if (a->scope_nesting > tos->alias_scope_nesting) { + QSLIST_REMOVE(&tos->aliases, a, InputVisitorAlias, next); + g_free(a); + } + } +} + +static void qobject_input_define_alias(Visitor *v, const char *name, + const char **source) +{ + QObjectInputVisitor *qiv = to_qiv(v); + StackObject *tos = QSLIST_FIRST(&qiv->stack); + InputVisitorAlias *alias = g_new(InputVisitorAlias, 1); + + /* + * The source path can become empty during alias propagation for + * wildcard aliases, but not when defining an alias (it would map + * all names onto themselves, which doesn't make sense). + */ + assert(source[0]); + + *alias = (InputVisitorAlias) { + .name = name, + .alias_so = tos, + .src = source, + }; + + QSLIST_INSERT_HEAD(&tos->aliases, alias, next); +} + static bool qobject_input_start_struct(Visitor *v, const char *name, void **obj, size_t size, Error **errp) { @@ -696,6 +838,9 @@ static QObjectInputVisitor *qobject_input_visitor_base_new(QObject *obj) v->visitor.end_list = qobject_input_end_list; v->visitor.start_alternate = qobject_input_start_alternate; v->visitor.optional = qobject_input_optional; + v->visitor.define_alias = qobject_input_define_alias; + v->visitor.start_alias_scope = qobject_input_start_alias_scope; + v->visitor.end_alias_scope = qobject_input_end_alias_scope; v->visitor.free = qobject_input_free; v->root = qobject_ref(obj);
This makes qobject-input-visitor remember the currently valid aliases in each StackObject. It doesn't actually allow using the aliases yet. Signed-off-by: Kevin Wolf <kwolf@redhat.com> --- qapi/qobject-input-visitor.c | 145 +++++++++++++++++++++++++++++++++++ 1 file changed, 145 insertions(+)