qemu-patch-raspberry4/qapi/qapi-visit-core.c
Eric Blake e65d89bf1a 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>
2016-02-19 11:08:57 +01:00

273 lines
6.6 KiB
C

/*
* Core Definitions for QAPI Visitor Classes
*
* Copyright (C) 2012-2016 Red Hat, Inc.
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qapi/qmp/qobject.h"
#include "qapi/qmp/qerror.h"
#include "qapi/visitor.h"
#include "qapi/visitor-impl.h"
void visit_start_struct(Visitor *v, const char *name, void **obj,
size_t size, Error **errp)
{
v->start_struct(v, name, obj, size, errp);
}
void visit_end_struct(Visitor *v, Error **errp)
{
v->end_struct(v, errp);
}
void visit_start_implicit_struct(Visitor *v, void **obj, size_t size,
Error **errp)
{
if (v->start_implicit_struct) {
v->start_implicit_struct(v, obj, size, errp);
}
}
void visit_end_implicit_struct(Visitor *v)
{
if (v->end_implicit_struct) {
v->end_implicit_struct(v);
}
}
void visit_start_list(Visitor *v, const char *name, Error **errp)
{
v->start_list(v, name, errp);
}
GenericList *visit_next_list(Visitor *v, GenericList **list, size_t size)
{
assert(list && size >= sizeof(GenericList));
return v->next_list(v, list, size);
}
void visit_end_list(Visitor *v)
{
v->end_list(v);
}
bool visit_start_union(Visitor *v, bool data_present, Error **errp)
{
if (v->start_union) {
return v->start_union(v, data_present, errp);
}
return true;
}
bool visit_optional(Visitor *v, const char *name, bool *present)
{
if (v->optional) {
v->optional(v, name, present);
}
return *present;
}
void visit_get_next_type(Visitor *v, const char *name, QType *type,
bool promote_int, Error **errp)
{
if (v->get_next_type) {
v->get_next_type(v, name, type, promote_int, errp);
}
}
void visit_type_enum(Visitor *v, const char *name, int *obj,
const char *const strings[], Error **errp)
{
v->type_enum(v, name, obj, strings, errp);
}
void visit_type_int(Visitor *v, const char *name, int64_t *obj, Error **errp)
{
v->type_int64(v, name, obj, errp);
}
static void visit_type_uintN(Visitor *v, uint64_t *obj, const char *name,
uint64_t max, const char *type, Error **errp)
{
Error *err = NULL;
uint64_t value = *obj;
v->type_uint64(v, name, &value, &err);
if (err) {
error_propagate(errp, err);
} else if (value > max) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
name ? name : "null", type);
} else {
*obj = value;
}
}
void visit_type_uint8(Visitor *v, const char *name, uint8_t *obj,
Error **errp)
{
uint64_t value = *obj;
visit_type_uintN(v, &value, name, UINT8_MAX, "uint8_t", errp);
*obj = value;
}
void visit_type_uint16(Visitor *v, const char *name, uint16_t *obj,
Error **errp)
{
uint64_t value = *obj;
visit_type_uintN(v, &value, name, UINT16_MAX, "uint16_t", errp);
*obj = value;
}
void visit_type_uint32(Visitor *v, const char *name, uint32_t *obj,
Error **errp)
{
uint64_t value = *obj;
visit_type_uintN(v, &value, name, UINT32_MAX, "uint32_t", errp);
*obj = value;
}
void visit_type_uint64(Visitor *v, const char *name, uint64_t *obj,
Error **errp)
{
v->type_uint64(v, name, obj, errp);
}
static void visit_type_intN(Visitor *v, int64_t *obj, const char *name,
int64_t min, int64_t max, const char *type,
Error **errp)
{
Error *err = NULL;
int64_t value = *obj;
v->type_int64(v, name, &value, &err);
if (err) {
error_propagate(errp, err);
} else if (value < min || value > max) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE,
name ? name : "null", type);
} else {
*obj = value;
}
}
void visit_type_int8(Visitor *v, const char *name, int8_t *obj, Error **errp)
{
int64_t value = *obj;
visit_type_intN(v, &value, name, INT8_MIN, INT8_MAX, "int8_t", errp);
*obj = value;
}
void visit_type_int16(Visitor *v, const char *name, int16_t *obj,
Error **errp)
{
int64_t value = *obj;
visit_type_intN(v, &value, name, INT16_MIN, INT16_MAX, "int16_t", errp);
*obj = value;
}
void visit_type_int32(Visitor *v, const char *name, int32_t *obj,
Error **errp)
{
int64_t value = *obj;
visit_type_intN(v, &value, name, INT32_MIN, INT32_MAX, "int32_t", errp);
*obj = value;
}
void visit_type_int64(Visitor *v, const char *name, int64_t *obj,
Error **errp)
{
v->type_int64(v, name, obj, errp);
}
void visit_type_size(Visitor *v, const char *name, uint64_t *obj,
Error **errp)
{
if (v->type_size) {
v->type_size(v, name, obj, errp);
} else {
v->type_uint64(v, name, obj, errp);
}
}
void visit_type_bool(Visitor *v, const char *name, bool *obj, Error **errp)
{
v->type_bool(v, name, obj, errp);
}
void visit_type_str(Visitor *v, const char *name, char **obj, Error **errp)
{
v->type_str(v, name, obj, errp);
}
void visit_type_number(Visitor *v, const char *name, double *obj,
Error **errp)
{
v->type_number(v, name, obj, errp);
}
void visit_type_any(Visitor *v, const char *name, QObject **obj, Error **errp)
{
v->type_any(v, name, obj, errp);
}
void output_type_enum(Visitor *v, const char *name, int *obj,
const char *const strings[], Error **errp)
{
int i = 0;
int value = *obj;
char *enum_str;
assert(strings);
while (strings[i++] != NULL);
if (value < 0 || value >= i - 1) {
error_setg(errp, QERR_INVALID_PARAMETER, name ? name : "null");
return;
}
enum_str = (char *)strings[value];
visit_type_str(v, name, &enum_str, errp);
}
void input_type_enum(Visitor *v, const char *name, int *obj,
const char *const strings[], Error **errp)
{
Error *local_err = NULL;
int64_t value = 0;
char *enum_str;
assert(strings);
visit_type_str(v, name, &enum_str, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
while (strings[value] != NULL) {
if (strcmp(strings[value], enum_str) == 0) {
break;
}
value++;
}
if (strings[value] == NULL) {
error_setg(errp, QERR_INVALID_PARAMETER, enum_str);
g_free(enum_str);
return;
}
g_free(enum_str);
*obj = value;
}