From adfb264c9ed04bfc694921b72173be8e29e90024 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Thu, 28 Apr 2016 15:45:20 -0600 Subject: qapi: Document visitor interfaces, add assertions The visitor interface for mapping between QObject/QemuOpts/string and QAPI is scandalously under-documented, making changes to visitor core, individual visitors, and users of visitors difficult to coordinate. Among other questions: when is it safe to pass NULL, vs. when a string must be provided; which visitors implement which callbacks; the difference between concrete and virtual visits. Correct this by retrofitting proper contracts, and document where some of the interface warts remain (for example, we may want to modify visit_end_* to require the same 'obj' as the visit_start counterpart, so the dealloc visitor can be simplified). Later patches in this series will tackle some, but not all, of these warts. Add assertions to (partially) enforce the contract. Some of these were only made possible by recent cleanup commits. Signed-off-by: Eric Blake Message-Id: <1461879932-9020-13-git-send-email-eblake@redhat.com> [Doc fix from Eric squashed in] Signed-off-by: Markus Armbruster --- include/qapi/string-output-visitor.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/qapi/string-output-visitor.h') diff --git a/include/qapi/string-output-visitor.h b/include/qapi/string-output-visitor.h index d99717f650..3bb09aff2f 100644 --- a/include/qapi/string-output-visitor.h +++ b/include/qapi/string-output-visitor.h @@ -17,6 +17,10 @@ typedef struct StringOutputVisitor StringOutputVisitor; +/* + * The string output visitor does not implement support for visiting + * QAPI structs, alternates, or arbitrary QTypes. + */ StringOutputVisitor *string_output_visitor_new(bool human); void string_output_visitor_cleanup(StringOutputVisitor *v); -- cgit 1.4.1 From 3bc97fd5924561d92f32758c67eaffd2e4e25038 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Thu, 28 Apr 2016 15:45:22 -0600 Subject: qapi: Add visit_type_null() visitor Right now, qmp-output-visitor happens to produce a QNull result if nothing is actually visited between the creation of the visitor and the request for the resulting QObject. A stronger protocol would require that a QMP output visit MUST visit something. But to still be able to produce a JSON 'null' output, we need a new visitor function that states our intentions. Yes, we could say that such a visit must go through visit_type_any(), but that feels clunky. So this patch introduces the new visit_type_null() interface and its no-op interface in the dealloc visitor, and stubs in the qmp visitors (the next patch will finish the implementation). For the visitors that will not implement the callback, document the situation. The code in qapi-visit-core unconditionally dereferences the callback pointer, so that a segfault will inform a developer if they need to implement the callback for their choice of visitor. Note that JSON has a primitive null type, with the single value null; likewise with the QNull type for QObject; but for QAPI, we just have the 'null' value without a null type. We may eventually want to add more support in QAPI for null (most likely, we'd use it via an alternate type that permits 'null' or an object); but we'll create that usage when we need it. Signed-off-by: Eric Blake Message-Id: <1461879932-9020-15-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster --- include/qapi/opts-visitor.h | 3 ++- include/qapi/string-input-visitor.h | 2 +- include/qapi/string-output-visitor.h | 2 +- include/qapi/visitor-impl.h | 3 +++ include/qapi/visitor.h | 12 ++++++++++++ qapi/qapi-dealloc-visitor.c | 5 +++++ qapi/qapi-visit-core.c | 5 +++++ qapi/qmp-input-visitor.c | 6 ++++++ qapi/qmp-output-visitor.c | 6 ++++++ 9 files changed, 41 insertions(+), 3 deletions(-) (limited to 'include/qapi/string-output-visitor.h') diff --git a/include/qapi/opts-visitor.h b/include/qapi/opts-visitor.h index 633aa7170f..fe37ed9a36 100644 --- a/include/qapi/opts-visitor.h +++ b/include/qapi/opts-visitor.h @@ -31,7 +31,8 @@ typedef struct OptsVisitor OptsVisitor; * - values above INT64_MAX or LLONG_MAX are rejected. * * The Opts input visitor does not implement support for visiting QAPI - * alternates, numbers (other than integers), or arbitrary QTypes. + * alternates, numbers (other than integers), null, or arbitrary + * QTypes. */ OptsVisitor *opts_visitor_new(const QemuOpts *opts); void opts_visitor_cleanup(OptsVisitor *nv); diff --git a/include/qapi/string-input-visitor.h b/include/qapi/string-input-visitor.h index fdf33ae2b4..a8d8f6723b 100644 --- a/include/qapi/string-input-visitor.h +++ b/include/qapi/string-input-visitor.h @@ -19,7 +19,7 @@ typedef struct StringInputVisitor StringInputVisitor; /* * The string input visitor does not implement support for visiting - * QAPI structs, alternates, or arbitrary QTypes. + * QAPI structs, alternates, null, or arbitrary QTypes. */ StringInputVisitor *string_input_visitor_new(const char *str); void string_input_visitor_cleanup(StringInputVisitor *v); diff --git a/include/qapi/string-output-visitor.h b/include/qapi/string-output-visitor.h index 3bb09aff2f..89b7e4bc9b 100644 --- a/include/qapi/string-output-visitor.h +++ b/include/qapi/string-output-visitor.h @@ -19,7 +19,7 @@ typedef struct StringOutputVisitor StringOutputVisitor; /* * The string output visitor does not implement support for visiting - * QAPI structs, alternates, or arbitrary QTypes. + * QAPI structs, alternates, null, or arbitrary QTypes. */ StringOutputVisitor *string_output_visitor_new(bool human); void string_output_visitor_cleanup(StringOutputVisitor *v); diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h index 796d1800d4..88d27d58de 100644 --- a/include/qapi/visitor-impl.h +++ b/include/qapi/visitor-impl.h @@ -90,6 +90,9 @@ struct Visitor void (*type_any)(Visitor *v, const char *name, QObject **obj, Error **errp); + /* Must be set to visit explicit null values. */ + void (*type_null)(Visitor *v, const char *name, Error **errp); + /* Must be set for input visitors, optional otherwise. The core * takes care of the return type in the public interface. */ void (*optional)(Visitor *v, const char *name, bool *present); diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h index 221163742c..709cca0774 100644 --- a/include/qapi/visitor.h +++ b/include/qapi/visitor.h @@ -522,4 +522,16 @@ void visit_type_number(Visitor *v, const char *name, double *obj, */ void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp); +/* + * Visit a JSON null value. + * + * @name expresses the relationship of the null value to its parent + * container; see the general description of @name above. + * + * Unlike all other visit_type_* functions, no obj parameter is + * needed; rather, this is a witness that an explicit null value is + * expected rather than any other type. + */ +void visit_type_null(Visitor *v, const char *name, Error **errp); + #endif diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c index c19a459391..413d525ad8 100644 --- a/qapi/qapi-dealloc-visitor.c +++ b/qapi/qapi-dealloc-visitor.c @@ -163,6 +163,10 @@ static void qapi_dealloc_type_anything(Visitor *v, const char *name, } } +static void qapi_dealloc_type_null(Visitor *v, const char *name, Error **errp) +{ +} + Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v) { return &v->visitor; @@ -193,6 +197,7 @@ QapiDeallocVisitor *qapi_dealloc_visitor_new(void) v->visitor.type_str = qapi_dealloc_type_str; v->visitor.type_number = qapi_dealloc_type_number; v->visitor.type_any = qapi_dealloc_type_anything; + v->visitor.type_null = qapi_dealloc_type_null; QTAILQ_INIT(&v->stack); diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c index 0f59a1d8e5..fe6afe8ca8 100644 --- a/qapi/qapi-visit-core.c +++ b/qapi/qapi-visit-core.c @@ -244,6 +244,11 @@ void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp) error_propagate(errp, err); } +void visit_type_null(Visitor *v, const char *name, Error **errp) +{ + v->type_null(v, name, errp); +} + static void output_type_enum(Visitor *v, const char *name, int *obj, const char *const strings[], Error **errp) { diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c index 515983357d..fa460a3c37 100644 --- a/qapi/qmp-input-visitor.c +++ b/qapi/qmp-input-visitor.c @@ -340,6 +340,11 @@ static void qmp_input_type_any(Visitor *v, const char *name, QObject **obj, *obj = qobj; } +static void qmp_input_type_null(Visitor *v, const char *name, Error **errp) +{ + abort(); +} + static void qmp_input_optional(Visitor *v, const char *name, bool *present) { QmpInputVisitor *qiv = to_qiv(v); @@ -383,6 +388,7 @@ QmpInputVisitor *qmp_input_visitor_new(QObject *obj, bool strict) v->visitor.type_str = qmp_input_type_str; v->visitor.type_number = qmp_input_type_number; v->visitor.type_any = qmp_input_type_any; + v->visitor.type_null = qmp_input_type_null; v->visitor.optional = qmp_input_optional; v->strict = strict; diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c index 1f2a7ba646..adf7731e3f 100644 --- a/qapi/qmp-output-visitor.c +++ b/qapi/qmp-output-visitor.c @@ -196,6 +196,11 @@ static void qmp_output_type_any(Visitor *v, const char *name, QObject **obj, qmp_output_add_obj(qov, name, *obj); } +static void qmp_output_type_null(Visitor *v, const char *name, Error **errp) +{ + abort(); +} + /* Finish building, and return the root object. Will not be NULL. */ QObject *qmp_output_get_qobject(QmpOutputVisitor *qov) { @@ -246,6 +251,7 @@ QmpOutputVisitor *qmp_output_visitor_new(void) v->visitor.type_str = qmp_output_type_str; v->visitor.type_number = qmp_output_type_number; v->visitor.type_any = qmp_output_type_any; + v->visitor.type_null = qmp_output_type_null; QTAILQ_INIT(&v->stack); -- cgit 1.4.1 From d9f62dde1303286b24ac8ce88be27e2b9b9c5f46 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Thu, 28 Apr 2016 15:45:31 -0600 Subject: qapi: Simplify semantics of visit_next_list() The semantics of the list visit are somewhat baroque, with the following pseudocode when FooList is used: start() for (prev = head; cur = next(prev); prev = &cur) { visit(&cur->value) } Note that these semantics (advance before visit) requires that the first call to next() return the list head, while all other calls return the next element of the list; that is, every visitor implementation is required to track extra state to decide whether to return the input as-is, or to advance. It also requires an argument of 'GenericList **' to next(), solely because the first iteration might need to modify the caller's GenericList head, so that all other calls have to do a layer of dereferencing. Thankfully, we only have two uses of list visits in the entire code base: one in spapr_drc (which completely avoids visit_next_list(), feeding in integers from a different source than uint8List), and one in qapi-visit.py. That is, all other list visitors are generated in qapi-visit.c, and share the same paradigm based on a qapi FooList type, so we can refactor how lists are laid out with minimal churn among clients. We can greatly simplify things by hoisting the special case into the start() routine, and flipping the order in the loop to visit before advance: start(head) for (tail = *head; tail; tail = next(tail)) { visit(&tail->value) } With the simpler semantics, visitors have less state to track, the argument to next() is reduced to 'GenericList *', and it also becomes obvious whether an input visitor is allocating a FooList during visit_start_list() (rather than the old way of not knowing if an allocation happened until the first visit_next_list()). As a minor drawback, we now allocate in two functions instead of one, and have to pass the size to both functions (unless we were to tweak the input visitors to cache the size to start_list for reuse during next_list, but that defeats the goal of less visitor state). The signature of visit_start_list() is chosen to match visit_start_struct(), with the new parameters after 'name'. The spapr_drc case is a virtual visit, done by passing NULL for list, similarly to how NULL is passed to visit_start_struct() when a qapi type is not used in those visits. It was easy to provide these semantics for qmp-output and dealloc visitors, and a bit harder for qmp-input (several prerequisite patches refactored things to make this patch straightforward). But it turned out that the string and opts visitors munge enough other state during visit_next_list() to make it easier to just document and require a GenericList visit for now; an assertion will remind us to adjust things if we need the semantics in the future. Several pre-requisite cleanup patches made the reshuffling of the various visitors easier; particularly the qmp input visitor. Signed-off-by: Eric Blake Message-Id: <1461879932-9020-24-git-send-email-eblake@redhat.com> Signed-off-by: Markus Armbruster --- docs/qapi-code-gen.txt | 16 ++++++------ hw/ppc/spapr_drc.c | 2 +- include/qapi/opts-visitor.h | 3 ++- include/qapi/string-input-visitor.h | 3 ++- include/qapi/string-output-visitor.h | 3 ++- include/qapi/visitor-impl.h | 8 +++--- include/qapi/visitor.h | 49 +++++++++++++++++++----------------- qapi/opts-visitor.c | 33 +++++++++++------------- qapi/qapi-dealloc-visitor.c | 35 ++++++-------------------- qapi/qapi-visit-core.c | 18 +++++++++---- qapi/qmp-input-visitor.c | 40 +++++++++++++++-------------- qapi/qmp-output-visitor.c | 22 ++++------------ qapi/string-input-visitor.c | 29 +++++++++------------ qapi/string-output-visitor.c | 41 +++++++++++------------------- scripts/qapi-visit.py | 16 ++++++------ tests/test-string-input-visitor.c | 2 -- 16 files changed, 142 insertions(+), 178 deletions(-) (limited to 'include/qapi/string-output-visitor.h') diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index d135847c87..fe61c5c423 100644 --- a/docs/qapi-code-gen.txt +++ b/docs/qapi-code-gen.txt @@ -912,18 +912,20 @@ Example: void visit_type_UserDefOneList(Visitor *v, const char *name, UserDefOneList **obj, Error **errp) { Error *err = NULL; - GenericList *i, **prev; + UserDefOneList *tail; + size_t size = sizeof(**obj); - visit_start_list(v, name, &err); + visit_start_list(v, name, (GenericList **)obj, size, &err); if (err) { goto out; } - for (prev = (GenericList **)obj; - !err && (i = visit_next_list(v, prev, sizeof(**obj))) != NULL; - prev = &i) { - UserDefOneList *native_i = (UserDefOneList *)i; - visit_type_UserDefOne(v, NULL, &native_i->value, &err); + for (tail = *obj; tail; + tail = (UserDefOneList *)visit_next_list(v, (GenericList *)tail, size)) { + visit_type_UserDefOne(v, NULL, &tail->value, &err); + if (err) { + break; + } } visit_end_list(v); diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c index e3a6191ad4..94c875d752 100644 --- a/hw/ppc/spapr_drc.c +++ b/hw/ppc/spapr_drc.c @@ -309,7 +309,7 @@ static void prop_get_fdt(Object *obj, Visitor *v, const char *name, int i; prop = fdt_get_property_by_offset(fdt, fdt_offset, &prop_len); name = fdt_string(fdt, fdt32_to_cpu(prop->nameoff)); - visit_start_list(v, name, &err); + visit_start_list(v, name, NULL, 0, &err); if (err) { error_propagate(errp, err); return; diff --git a/include/qapi/opts-visitor.h b/include/qapi/opts-visitor.h index fe37ed9a36..ae1bf7cf51 100644 --- a/include/qapi/opts-visitor.h +++ b/include/qapi/opts-visitor.h @@ -32,7 +32,8 @@ typedef struct OptsVisitor OptsVisitor; * * The Opts input visitor does not implement support for visiting QAPI * alternates, numbers (other than integers), null, or arbitrary - * QTypes. + * QTypes. It also requires a non-null list argument to + * visit_start_list(). */ OptsVisitor *opts_visitor_new(const QemuOpts *opts); void opts_visitor_cleanup(OptsVisitor *nv); diff --git a/include/qapi/string-input-visitor.h b/include/qapi/string-input-visitor.h index a8d8f6723b..7b76c2b9e3 100644 --- a/include/qapi/string-input-visitor.h +++ b/include/qapi/string-input-visitor.h @@ -19,7 +19,8 @@ typedef struct StringInputVisitor StringInputVisitor; /* * The string input visitor does not implement support for visiting - * QAPI structs, alternates, null, or arbitrary QTypes. + * QAPI structs, alternates, null, or arbitrary QTypes. It also + * requires a non-null list argument to visit_start_list(). */ StringInputVisitor *string_input_visitor_new(const char *str); void string_input_visitor_cleanup(StringInputVisitor *v); diff --git a/include/qapi/string-output-visitor.h b/include/qapi/string-output-visitor.h index 89b7e4bc9b..e10522a35b 100644 --- a/include/qapi/string-output-visitor.h +++ b/include/qapi/string-output-visitor.h @@ -19,7 +19,8 @@ typedef struct StringOutputVisitor StringOutputVisitor; /* * The string output visitor does not implement support for visiting - * QAPI structs, alternates, null, or arbitrary QTypes. + * QAPI structs, alternates, null, or arbitrary QTypes. It also + * requires a non-null list argument to visit_start_list(). */ StringOutputVisitor *string_output_visitor_new(bool human); void string_output_visitor_cleanup(StringOutputVisitor *v); diff --git a/include/qapi/visitor-impl.h b/include/qapi/visitor-impl.h index b20a9226e0..145afd03e7 100644 --- a/include/qapi/visitor-impl.h +++ b/include/qapi/visitor-impl.h @@ -49,11 +49,13 @@ struct Visitor /* Must be set to visit structs */ void (*end_struct)(Visitor *v); - /* Must be set */ - void (*start_list)(Visitor *v, const char *name, Error **errp); + /* Must be set; implementations may require @list to be non-null, + * but must document it. */ + void (*start_list)(Visitor *v, const char *name, GenericList **list, + size_t size, Error **errp); /* Must be set */ - GenericList *(*next_list)(Visitor *v, GenericList **list, size_t size); + GenericList *(*next_list)(Visitor *v, GenericList *tail, size_t size); /* Must be set */ void (*end_list)(Visitor *v); diff --git a/include/qapi/visitor.h b/include/qapi/visitor.h index fe268fe78d..8de6b436fb 100644 --- a/include/qapi/visitor.h +++ b/include/qapi/visitor.h @@ -176,7 +176,7 @@ * if (err) { * goto out; * } - * visit_start_list(v, "list", &err); + * visit_start_list(v, "list", NULL, 0, &err); * if (err) { * goto outobj; * } @@ -281,19 +281,27 @@ void visit_end_struct(Visitor *v); * @name expresses the relationship of this list to its parent * container; see the general description of @name above. * + * @list must be non-NULL for a real walk, in which case @size + * determines how much memory an input visitor will allocate into + * *@list (at least sizeof(GenericList)). Some visitors also allow + * @list to be NULL for a virtual walk, in which case @size is + * ignored. + * * @errp obeys typical error usage, and reports failures such as a - * member @name is not present, or present but not a list. + * member @name is not present, or present but not a list. On error, + * input visitors set *@list to NULL. * * After visit_start_list() succeeds, the caller may visit its members - * one after the other. A real visit uses visit_next_list() for - * traversing the linked list, while a virtual visit uses other means. - * For each list element, call the appropriate visit_type_FOO() with - * name set to NULL and obj set to the address of the value member of - * the list element. Finally, visit_end_list() needs to be called to - * clean up, even if intermediate visits fail. See the examples - * above. + * one after the other. A real visit (where @obj is non-NULL) uses + * visit_next_list() for traversing the linked list, while a virtual + * visit (where @obj is NULL) uses other means. For each list + * element, call the appropriate visit_type_FOO() with name set to + * NULL and obj set to the address of the value member of the list + * element. Finally, visit_end_list() needs to be called to clean up, + * even if intermediate visits fail. See the examples above. */ -void visit_start_list(Visitor *v, const char *name, Error **errp); +void visit_start_list(Visitor *v, const char *name, GenericList **list, + size_t size, Error **errp); /* * Iterate over a GenericList during a non-virtual list visit. @@ -301,20 +309,15 @@ void visit_start_list(Visitor *v, const char *name, Error **errp); * @size represents the size of a linked list node (at least * sizeof(GenericList)). * - * @list must not be NULL; on the first call, @list contains the - * address of the list head, and on subsequent calls *@list must be - * the previously returned value. Should be called in a loop until a - * NULL return or error occurs; for each non-NULL return, the caller - * then calls the appropriate visit_type_*() for the element type - * of the list, with that function's name parameter set to NULL and - * obj set to the address of (*@list)->value. - * - * FIXME: This interface is awkward; it requires all callbacks to - * track whether it is the first or a subsequent call. A better - * interface would pass the head of the list through - * visit_start_list(). + * @tail must not be NULL; on the first call, @tail is the value of + * *list after visit_start_list(), and on subsequent calls @tail must + * be the previously returned value. Should be called in a loop until + * a NULL return or error occurs; for each non-NULL return, the caller + * then calls the appropriate visit_type_*() for the element type of + * the list, with that function's name parameter set to NULL and obj + * set to the address of @tail->value. */ -GenericList *visit_next_list(Visitor *v, GenericList **list, size_t size); +GenericList *visit_next_list(Visitor *v, GenericList *tail, size_t size); /* * Complete a list visit started earlier. diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c index ece0598e34..4cf1cf885b 100644 --- a/qapi/opts-visitor.c +++ b/qapi/opts-visitor.c @@ -23,9 +23,8 @@ enum ListMode { LM_NONE, /* not traversing a list of repeated options */ - LM_STARTED, /* opts_start_list() succeeded */ - LM_IN_PROGRESS, /* opts_next_list() has been called. + LM_IN_PROGRESS, /* opts_next_list() ready to be called. * * Generating the next list link will consume the most * recently parsed QemuOpt instance of the repeated @@ -214,35 +213,33 @@ lookup_distinct(const OptsVisitor *ov, const char *name, Error **errp) static void -opts_start_list(Visitor *v, const char *name, Error **errp) +opts_start_list(Visitor *v, const char *name, GenericList **list, size_t size, + Error **errp) { OptsVisitor *ov = to_ov(v); /* we can't traverse a list in a list */ assert(ov->list_mode == LM_NONE); + /* we don't support visits without a list */ + assert(list); ov->repeated_opts = lookup_distinct(ov, name, errp); - if (ov->repeated_opts != NULL) { - ov->list_mode = LM_STARTED; + if (ov->repeated_opts) { + ov->list_mode = LM_IN_PROGRESS; + *list = g_malloc0(size); + } else { + *list = NULL; } } static GenericList * -opts_next_list(Visitor *v, GenericList **list, size_t size) +opts_next_list(Visitor *v, GenericList *tail, size_t size) { OptsVisitor *ov = to_ov(v); - GenericList **link; switch (ov->list_mode) { - case LM_STARTED: - ov->list_mode = LM_IN_PROGRESS; - link = list; - break; - case LM_SIGNED_INTERVAL: case LM_UNSIGNED_INTERVAL: - link = &(*list)->next; - if (ov->list_mode == LM_SIGNED_INTERVAL) { if (ov->range_next.s < ov->range_limit.s) { ++ov->range_next.s; @@ -263,7 +260,6 @@ opts_next_list(Visitor *v, GenericList **list, size_t size) g_hash_table_remove(ov->unprocessed_opts, opt->name); return NULL; } - link = &(*list)->next; break; } @@ -271,8 +267,8 @@ opts_next_list(Visitor *v, GenericList **list, size_t size) abort(); } - *link = g_malloc0(size); - return *link; + tail->next = g_malloc0(size); + return tail->next; } @@ -281,8 +277,7 @@ opts_end_list(Visitor *v) { OptsVisitor *ov = to_ov(v); - assert(ov->list_mode == LM_STARTED || - ov->list_mode == LM_IN_PROGRESS || + assert(ov->list_mode == LM_IN_PROGRESS || ov->list_mode == LM_SIGNED_INTERVAL || ov->list_mode == LM_UNSIGNED_INTERVAL); ov->repeated_opts = NULL; diff --git a/qapi/qapi-dealloc-visitor.c b/qapi/qapi-dealloc-visitor.c index 9005badb25..cd68b55a1a 100644 --- a/qapi/qapi-dealloc-visitor.c +++ b/qapi/qapi-dealloc-visitor.c @@ -22,7 +22,6 @@ typedef struct StackEntry { void *value; - bool is_list_head; QTAILQ_ENTRY(StackEntry) node; } StackEntry; @@ -43,10 +42,6 @@ static void qapi_dealloc_push(QapiDeallocVisitor *qov, void *value) e->value = value; - /* see if we're just pushing a list head tracker */ - if (value == NULL) { - e->is_list_head = true; - } QTAILQ_INSERT_HEAD(&qov->stack, e, node); } @@ -93,38 +88,22 @@ static void qapi_dealloc_end_alternate(Visitor *v) } } -static void qapi_dealloc_start_list(Visitor *v, const char *name, Error **errp) +static void qapi_dealloc_start_list(Visitor *v, const char *name, + GenericList **list, size_t size, + Error **errp) { - QapiDeallocVisitor *qov = to_qov(v); - qapi_dealloc_push(qov, NULL); } -static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **listp, +static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList *tail, size_t size) { - GenericList *list = *listp; - QapiDeallocVisitor *qov = to_qov(v); - StackEntry *e = QTAILQ_FIRST(&qov->stack); - - if (e && e->is_list_head) { - e->is_list_head = false; - return list; - } - - if (list) { - list = list->next; - g_free(*listp); - return list; - } - - return NULL; + GenericList *next = tail->next; + g_free(tail); + return next; } static void qapi_dealloc_end_list(Visitor *v) { - QapiDeallocVisitor *qov = to_qov(v); - void *obj = qapi_dealloc_pop(qov); - assert(obj == NULL); /* should've been list head tracker with no payload */ } static void qapi_dealloc_type_str(Visitor *v, const char *name, char **obj, diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c index 58144f67b7..d6bf4bd253 100644 --- a/qapi/qapi-visit-core.c +++ b/qapi/qapi-visit-core.c @@ -48,15 +48,23 @@ void visit_end_struct(Visitor *v) v->end_struct(v); } -void visit_start_list(Visitor *v, const char *name, Error **errp) +void visit_start_list(Visitor *v, const char *name, GenericList **list, + size_t size, Error **errp) { - v->start_list(v, name, errp); + Error *err = NULL; + + assert(!list || size >= sizeof(GenericList)); + v->start_list(v, name, list, size, &err); + if (list && v->type == VISITOR_INPUT) { + assert(!(err && *list)); + } + error_propagate(errp, err); } -GenericList *visit_next_list(Visitor *v, GenericList **list, size_t size) +GenericList *visit_next_list(Visitor *v, GenericList *tail, size_t size) { - assert(list && size >= sizeof(GenericList)); - return v->next_list(v, list, size); + assert(tail && size >= sizeof(GenericList)); + return v->next_list(v, tail, size); } void visit_end_list(Visitor *v) diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c index 90b9df11c4..aea90a1378 100644 --- a/qapi/qmp-input-visitor.c +++ b/qapi/qmp-input-visitor.c @@ -29,7 +29,6 @@ typedef struct StackObject GHashTable *h; /* If obj is dict: unvisited keys */ const QListEntry *entry; /* If obj is list: unvisited tail */ - bool first; /* If obj is list: next_list() not yet called? */ } StackObject; struct QmpInputVisitor @@ -81,7 +80,6 @@ static QObject *qmp_input_get_object(QmpInputVisitor *qiv, } else { assert(qobject_type(qobj) == QTYPE_QLIST); assert(!name); - assert(!tos->first); ret = qlist_entry_obj(tos->entry); if (consume) { tos->entry = qlist_next(tos->entry); @@ -97,7 +95,8 @@ static void qdict_add_key(const char *key, QObject *obj, void *opaque) g_hash_table_insert(h, (gpointer) key, NULL); } -static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp) +static const QListEntry *qmp_input_push(QmpInputVisitor *qiv, QObject *obj, + Error **errp) { GHashTable *h; StackObject *tos = &qiv->stack[qiv->nb_stack]; @@ -105,7 +104,7 @@ static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp) assert(obj); if (qiv->nb_stack >= QIV_STACK_SIZE) { error_setg(errp, "An internal buffer overran"); - return; + return NULL; } tos->obj = obj; @@ -118,10 +117,10 @@ static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp) tos->h = h; } else if (qobject_type(obj) == QTYPE_QLIST) { tos->entry = qlist_first(qobject_to_qlist(obj)); - tos->first = true; } qiv->nb_stack++; + return tos->entry; } @@ -192,40 +191,43 @@ static void qmp_input_start_struct(Visitor *v, const char *name, void **obj, } -static void qmp_input_start_list(Visitor *v, const char *name, Error **errp) +static void qmp_input_start_list(Visitor *v, const char *name, + GenericList **list, size_t size, Error **errp) { QmpInputVisitor *qiv = to_qiv(v); QObject *qobj = qmp_input_get_object(qiv, name, true); + const QListEntry *entry; if (!qobj || qobject_type(qobj) != QTYPE_QLIST) { + if (list) { + *list = NULL; + } error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "list"); return; } - qmp_input_push(qiv, qobj, errp); + entry = qmp_input_push(qiv, qobj, errp); + if (list) { + if (entry) { + *list = g_malloc0(size); + } else { + *list = NULL; + } + } } -static GenericList *qmp_input_next_list(Visitor *v, GenericList **list, +static GenericList *qmp_input_next_list(Visitor *v, GenericList *tail, size_t size) { QmpInputVisitor *qiv = to_qiv(v); - GenericList *entry; StackObject *so = &qiv->stack[qiv->nb_stack - 1]; if (!so->entry) { return NULL; } - - entry = g_malloc0(size); - if (so->first) { - *list = entry; - so->first = false; - } else { - (*list)->next = entry; - } - - return entry; + tail->next = g_malloc0(size); + return tail->next; } diff --git a/qapi/qmp-output-visitor.c b/qapi/qmp-output-visitor.c index 232ad58221..4d3cf78333 100644 --- a/qapi/qmp-output-visitor.c +++ b/qapi/qmp-output-visitor.c @@ -22,7 +22,6 @@ typedef struct QStackEntry { QObject *value; - bool is_list_head; QTAILQ_ENTRY(QStackEntry) node; } QStackEntry; @@ -52,9 +51,6 @@ static void qmp_output_push_obj(QmpOutputVisitor *qov, QObject *value) assert(qov->root); assert(value); e->value = value; - if (qobject_type(e->value) == QTYPE_QLIST) { - e->is_list_head = true; - } QTAILQ_INSERT_HEAD(&qov->stack, e, node); } @@ -118,7 +114,9 @@ static void qmp_output_end_struct(Visitor *v) assert(qobject_type(value) == QTYPE_QDICT); } -static void qmp_output_start_list(Visitor *v, const char *name, Error **errp) +static void qmp_output_start_list(Visitor *v, const char *name, + GenericList **listp, size_t size, + Error **errp) { QmpOutputVisitor *qov = to_qov(v); QList *list = qlist_new(); @@ -127,20 +125,10 @@ static void qmp_output_start_list(Visitor *v, const char *name, Error **errp) qmp_output_push(qov, list); } -static GenericList *qmp_output_next_list(Visitor *v, GenericList **listp, +static GenericList *qmp_output_next_list(Visitor *v, GenericList *tail, size_t size) { - GenericList *list = *listp; - QmpOutputVisitor *qov = to_qov(v); - QStackEntry *e = QTAILQ_FIRST(&qov->stack); - - assert(e); - if (e->is_list_head) { - e->is_list_head = false; - return list; - } - - return list ? list->next : NULL; + return tail->next; } static void qmp_output_end_list(Visitor *v) diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c index ad150dccf6..30b58791c9 100644 --- a/qapi/string-input-visitor.c +++ b/qapi/string-input-visitor.c @@ -25,8 +25,6 @@ struct StringInputVisitor { Visitor visitor; - bool head; - GList *ranges; GList *cur_range; int64_t cur; @@ -128,11 +126,16 @@ error: } static void -start_list(Visitor *v, const char *name, Error **errp) +start_list(Visitor *v, const char *name, GenericList **list, size_t size, + Error **errp) { StringInputVisitor *siv = to_siv(v); + /* We don't support visits without a list */ + assert(list); + if (parse_str(siv, name, errp) < 0) { + *list = NULL; return; } @@ -142,13 +145,15 @@ start_list(Visitor *v, const char *name, Error **errp) if (r) { siv->cur = r->begin; } + *list = g_malloc0(size); + } else { + *list = NULL; } } -static GenericList *next_list(Visitor *v, GenericList **list, size_t size) +static GenericList *next_list(Visitor *v, GenericList *tail, size_t size) { StringInputVisitor *siv = to_siv(v); - GenericList **link; Range *r; if (!siv->ranges || !siv->cur_range) { @@ -172,21 +177,12 @@ static GenericList *next_list(Visitor *v, GenericList **list, size_t size) siv->cur = r->begin; } - if (siv->head) { - link = list; - siv->head = false; - } else { - link = &(*list)->next; - } - - *link = g_malloc0(size); - return *link; + tail->next = g_malloc0(size); + return tail->next; } static void end_list(Visitor *v) { - StringInputVisitor *siv = to_siv(v); - siv->head = true; } static void parse_type_int64(Visitor *v, const char *name, int64_t *obj, @@ -369,6 +365,5 @@ StringInputVisitor *string_input_visitor_new(const char *str) v->visitor.optional = parse_optional; v->string = str; - v->head = true; return v; } diff --git a/qapi/string-output-visitor.c b/qapi/string-output-visitor.c index 0d44d7e6a5..d01319628b 100644 --- a/qapi/string-output-visitor.c +++ b/qapi/string-output-visitor.c @@ -20,7 +20,7 @@ enum ListMode { LM_NONE, /* not traversing a list of repeated options */ - LM_STARTED, /* start_list() succeeded */ + LM_STARTED, /* next_list() ready to be called */ LM_IN_PROGRESS, /* next_list() has been called. * @@ -48,7 +48,7 @@ enum ListMode { LM_UNSIGNED_INTERVAL,/* Same as above, only for an unsigned interval. */ - LM_END + LM_END, /* next_list() called, about to see last element. */ }; typedef enum ListMode ListMode; @@ -58,7 +58,6 @@ struct StringOutputVisitor Visitor visitor; bool human; GString *string; - bool head; ListMode list_mode; union { int64_t s; @@ -266,39 +265,29 @@ static void print_type_number(Visitor *v, const char *name, double *obj, } static void -start_list(Visitor *v, const char *name, Error **errp) +start_list(Visitor *v, const char *name, GenericList **list, size_t size, + Error **errp) { StringOutputVisitor *sov = to_sov(v); /* we can't traverse a list in a list */ assert(sov->list_mode == LM_NONE); - sov->list_mode = LM_STARTED; - sov->head = true; + /* We don't support visits without a list */ + assert(list); + /* List handling is only needed if there are at least two elements */ + if (*list && (*list)->next) { + sov->list_mode = LM_STARTED; + } } -static GenericList *next_list(Visitor *v, GenericList **list, size_t size) +static GenericList *next_list(Visitor *v, GenericList *tail, size_t size) { StringOutputVisitor *sov = to_sov(v); - GenericList *ret = NULL; - if (*list) { - if (sov->head) { - ret = *list; - } else { - ret = (*list)->next; - } + GenericList *ret = tail->next; - if (sov->head) { - if (ret && ret->next == NULL) { - sov->list_mode = LM_NONE; - } - sov->head = false; - } else { - if (ret && ret->next == NULL) { - sov->list_mode = LM_END; - } - } + if (ret && !ret->next) { + sov->list_mode = LM_END; } - return ret; } @@ -311,8 +300,6 @@ static void end_list(Visitor *v) sov->list_mode == LM_NONE || sov->list_mode == LM_IN_PROGRESS); sov->list_mode = LM_NONE; - sov->head = true; - } char *string_output_get_string(StringOutputVisitor *sov) diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py index bdf8971440..8b7efcc74a 100644 --- a/scripts/qapi-visit.py +++ b/scripts/qapi-visit.py @@ -117,18 +117,20 @@ def gen_visit_list(name, element_type): void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp) { Error *err = NULL; - GenericList *i, **prev; + %(c_name)s *tail; + size_t size = sizeof(**obj); - visit_start_list(v, name, &err); + visit_start_list(v, name, (GenericList **)obj, size, &err); if (err) { goto out; } - for (prev = (GenericList **)obj; - !err && (i = visit_next_list(v, prev, sizeof(**obj))) != NULL; - prev = &i) { - %(c_name)s *native_i = (%(c_name)s *)i; - visit_type_%(c_elt_type)s(v, NULL, &native_i->value, &err); + for (tail = *obj; tail; + tail = (%(c_name)s *)visit_next_list(v, (GenericList *)tail, size)) { + visit_type_%(c_elt_type)s(v, NULL, &tail->value, &err); + if (err) { + break; + } } visit_end_list(v); diff --git a/tests/test-string-input-visitor.c b/tests/test-string-input-visitor.c index f99824d240..5a56920222 100644 --- a/tests/test-string-input-visitor.c +++ b/tests/test-string-input-visitor.c @@ -98,8 +98,6 @@ static void test_visitor_in_intList(TestInputVisitorData *data, v = visitor_input_test_init(data, "not an int list"); - /* FIXME: res should be NULL on failure, regardless of starting value */ - res = NULL; visit_type_int16List(v, NULL, &res, &err); error_free_or_abort(&err); g_assert(!res); -- cgit 1.4.1