2012-02-09 12:11:52 +04:00
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/*
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* Core Definitions for QAPI Visitor implementations
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*
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2016-01-29 16:48:51 +03:00
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* Copyright (C) 2012-2016 Red Hat, Inc.
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2012-02-09 12:11:52 +04:00
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*
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* Author: Paolo Bonizni <pbonzini@redhat.com>
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*
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* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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* See the COPYING.LIB file in the top-level directory.
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*
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*/
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#ifndef QAPI_VISITOR_IMPL_H
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#define QAPI_VISITOR_IMPL_H
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2012-12-17 21:19:43 +04:00
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#include "qapi/visitor.h"
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2012-02-09 12:11:52 +04:00
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2012-12-06 14:28:04 +04:00
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struct Visitor
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{
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/* Must be set */
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2016-01-29 16:48:56 +03:00
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void (*start_struct)(Visitor *v, const char *name, void **obj,
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2016-01-29 16:48:57 +03:00
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size_t size, Error **errp);
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2012-12-06 14:28:04 +04:00
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void (*end_struct)(Visitor *v, Error **errp);
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void (*start_list)(Visitor *v, const char *name, Error **errp);
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2016-01-29 16:48:59 +03:00
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/* Must be set */
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qapi: Adjust layout of FooList types
By sticking the next pointer first, we don't need a union with
64-bit padding for smaller types. On 32-bit platforms, this
can reduce the size of uint8List from 16 bytes (or 12, depending
on whether 64-bit ints can tolerate 4-byte alignment) down to 8.
It has no effect on 64-bit platforms (where alignment still
dictates a 16-byte struct); but fewer anonymous unions is still
a win in my book.
It requires visit_next_list() to gain a size parameter, to know
what size element to allocate; comparable to the size parameter
of visit_start_struct().
I debated about going one step further, to allow for fewer casts,
by doing:
typedef GenericList GenericList;
struct GenericList {
GenericList *next;
};
struct FooList {
GenericList base;
Foo *value;
};
so that you convert to 'GenericList *' by '&foolist->base', and
back by 'container_of(generic, GenericList, base)' (as opposed to
the existing '(GenericList *)foolist' and '(FooList *)generic').
But doing that would require hoisting the declaration of
GenericList prior to inclusion of qapi-types.h, rather than its
current spot in visitor.h; it also makes iteration a bit more
verbose through 'foolist->base.next' instead of 'foolist->next'.
Note that for lists of objects, the 'value' payload is still
hidden behind a boxed pointer. Someday, it would be nice to do:
struct FooList {
FooList *next;
Foo value;
};
for one less level of malloc for each list element. This patch
is a step in that direction (now that 'next' is no longer at a
fixed non-zero offset within the struct, we can store more than
just a pointer's-worth of data as the value payload), but the
actual conversion would be a task for another series, as it will
touch a lot of code.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1455778109-6278-10-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-18 09:48:23 +03:00
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GenericList *(*next_list)(Visitor *v, GenericList **list, size_t size);
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2016-01-29 16:48:59 +03:00
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/* Must be set */
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void (*end_list)(Visitor *v);
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2012-12-06 14:28:04 +04:00
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qapi: Change visit_start_implicit_struct to visit_start_alternate
After recent changes, the only remaining use of
visit_start_implicit_struct() is for allocating the space needed
when visiting an alternate. Since the term 'implicit struct' is
hard to explain, rename the function to its current usage. While
at it, we can merge the functionality of visit_get_next_type()
into the same function, making it more like visit_start_struct().
Generated code is now slightly smaller:
| {
| Error *err = NULL;
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|- visit_start_implicit_struct(v, (void**) obj, sizeof(BlockdevRef), &err);
|+ visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj),
|+ true, &err);
| if (err) {
| goto out;
| }
|- visit_get_next_type(v, name, &(*obj)->type, true, &err);
|- if (err) {
|- goto out_obj;
|- }
| switch ((*obj)->type) {
| case QTYPE_QDICT:
| visit_start_struct(v, name, NULL, 0, &err);
...
| }
|-out_obj:
|- visit_end_implicit_struct(v);
|+ visit_end_alternate(v);
| out:
| error_propagate(errp, err);
| }
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1455778109-6278-16-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-02-18 09:48:29 +03:00
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/* Optional, needed for input and dealloc visitors. */
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void (*start_alternate)(Visitor *v, const char *name,
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GenericAlternate **obj, size_t size,
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bool promote_int, Error **errp);
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/* Optional, needed for dealloc visitor. */
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void (*end_alternate)(Visitor *v);
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/* Must be set. */
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2016-01-29 16:48:56 +03:00
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void (*type_enum)(Visitor *v, const char *name, int *obj,
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2016-01-29 16:48:57 +03:00
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const char *const strings[], Error **errp);
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2012-12-06 14:28:04 +04:00
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qapi: Prefer type_int64 over type_int in visitors
The qapi builtin type 'int' is basically shorthand for the type
'int64'. In fact, since no visitor was providing the optional
type_int64() callback, visit_type_int64() was just always falling
back to type_int(), cementing the equivalence between the types.
However, some visitors are providing a type_uint64() callback.
For purposes of code consistency, it is nicer if all visitors
use the paired type_int64/type_uint64 names rather than the
mismatched type_int/type_uint64. So this patch just renames
the signed int callbacks in place, dropping the type_int()
callback as redundant, and a later patch will focus on the
unsigned int callbacks.
Add some FIXMEs to questionable reuse of errp in code touched
by the rename, while at it (the reuse works as long as the
callbacks don't modify value when setting an error, but it's not
a good example to set) - a later patch will then fix those.
No change in functionality here, although further cleanups are
in the pipeline.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1454075341-13658-14-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-01-29 16:48:49 +03:00
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/* Must be set. */
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2016-01-29 16:48:56 +03:00
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void (*type_int64)(Visitor *v, const char *name, int64_t *obj,
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qapi: Prefer type_int64 over type_int in visitors
The qapi builtin type 'int' is basically shorthand for the type
'int64'. In fact, since no visitor was providing the optional
type_int64() callback, visit_type_int64() was just always falling
back to type_int(), cementing the equivalence between the types.
However, some visitors are providing a type_uint64() callback.
For purposes of code consistency, it is nicer if all visitors
use the paired type_int64/type_uint64 names rather than the
mismatched type_int/type_uint64. So this patch just renames
the signed int callbacks in place, dropping the type_int()
callback as redundant, and a later patch will focus on the
unsigned int callbacks.
Add some FIXMEs to questionable reuse of errp in code touched
by the rename, while at it (the reuse works as long as the
callbacks don't modify value when setting an error, but it's not
a good example to set) - a later patch will then fix those.
No change in functionality here, although further cleanups are
in the pipeline.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1454075341-13658-14-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-01-29 16:48:49 +03:00
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Error **errp);
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/* Must be set. */
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2016-01-29 16:48:56 +03:00
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void (*type_uint64)(Visitor *v, const char *name, uint64_t *obj,
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qapi: Make all visitors supply uint64 callbacks
Our qapi visitor contract supports multiple integer visitors,
but left the type_uint64 visitor as optional (falling back on
type_int64); which in turn can lead to awkward behavior with
numbers larger than INT64_MAX (the user has to be aware of
twos complement, and deal with negatives).
This patch does not address the disparity in handling large
values as negatives. It merely moves the fallback from uint64
to int64 from the visitor core to the visitors, where the issue
can actually be fixed, by implementing the missing type_uint64()
callbacks on top of the respective type_int64() callbacks, and
with a FIXME comment explaining why that's wrong.
With that done, we now have a type_uint64() callback in every
driver, so we can make it mandatory from the core. And although
the type_int64() callback can cover the entire valid range of
type_uint{8,16,32} on valid user input, using type_uint64() to
avoid mixed signedness makes more sense.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1454075341-13658-15-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-01-29 16:48:50 +03:00
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Error **errp);
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/* Optional; fallback is type_uint64(). */
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2016-01-29 16:48:56 +03:00
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void (*type_size)(Visitor *v, const char *name, uint64_t *obj,
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qapi: Make all visitors supply uint64 callbacks
Our qapi visitor contract supports multiple integer visitors,
but left the type_uint64 visitor as optional (falling back on
type_int64); which in turn can lead to awkward behavior with
numbers larger than INT64_MAX (the user has to be aware of
twos complement, and deal with negatives).
This patch does not address the disparity in handling large
values as negatives. It merely moves the fallback from uint64
to int64 from the visitor core to the visitors, where the issue
can actually be fixed, by implementing the missing type_uint64()
callbacks on top of the respective type_int64() callbacks, and
with a FIXME comment explaining why that's wrong.
With that done, we now have a type_uint64() callback in every
driver, so we can make it mandatory from the core. And although
the type_int64() callback can cover the entire valid range of
type_uint{8,16,32} on valid user input, using type_uint64() to
avoid mixed signedness makes more sense.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1454075341-13658-15-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-01-29 16:48:50 +03:00
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Error **errp);
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/* Must be set. */
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2016-01-29 16:48:56 +03:00
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void (*type_bool)(Visitor *v, const char *name, bool *obj, Error **errp);
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void (*type_str)(Visitor *v, const char *name, char **obj, Error **errp);
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void (*type_number)(Visitor *v, const char *name, double *obj,
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2012-12-06 14:28:04 +04:00
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Error **errp);
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2016-01-29 16:48:56 +03:00
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void (*type_any)(Visitor *v, const char *name, QObject **obj,
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2015-09-16 14:06:24 +03:00
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Error **errp);
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2012-12-06 14:28:04 +04:00
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2015-12-02 08:20:52 +03:00
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/* May be NULL; most useful for input visitors. */
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2016-01-29 16:48:56 +03:00
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void (*optional)(Visitor *v, const char *name, bool *present);
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2012-12-06 14:28:04 +04:00
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};
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2016-01-29 16:48:56 +03:00
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void input_type_enum(Visitor *v, const char *name, int *obj,
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2016-01-29 16:48:57 +03:00
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const char *const strings[], Error **errp);
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2016-01-29 16:48:56 +03:00
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void output_type_enum(Visitor *v, const char *name, int *obj,
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2016-01-29 16:48:57 +03:00
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const char *const strings[], Error **errp);
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2012-02-09 12:11:52 +04:00
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#endif
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