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OptsVisitor: introduce basic list modes 

We're going to need more state while processing a list of repeated
options. This change eliminates "repeated_opts_first" and adds a new state
variable:

  list_mode       repeated_opts  repeated_opts_first
  --------------  -------------  -------------------
  LM_NONE         NULL           false
  LM_STARTED      non-NULL       true
  LM_IN_PROGRESS  non-NULL       false

Additionally, it is documented that lookup_scalar() and processed(), both
called by opts_type_XXX(), are invalid in LM_STARTED -- generated qapi
code calls opts_next_list() to allocate the very first link before trying
to parse a scalar into it. List mode restrictions are expressed in
positive / inclusive form.

Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
This commit is contained in:
Laszlo Ersek 2013-08-20 00:35:33 +02:00 committed by Luiz Capitulino
parent 4a44d85e28
commit d957043412
1 changed files with 35 additions and 10 deletions
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45
qapi/opts-visitor.c
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@ -1,7 +1,7 @@
/*
* Options Visitor
*
* Copyright Red Hat, Inc. 2012
* Copyright Red Hat, Inc. 2012, 2013
*
* Author: Laszlo Ersek <lersek@redhat.com>
*
@ -18,6 +18,15 @@
#include "qapi/visitor-impl.h"
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 */
};
typedef enum ListMode ListMode;
struct OptsVisitor
{
Visitor visitor;
@ -35,8 +44,8 @@ struct OptsVisitor
/* The list currently being traversed with opts_start_list() /
* opts_next_list(). The list must have a struct element type in the
* schema, with a single mandatory scalar member. */
ListMode list_mode;
GQueue *repeated_opts;
bool repeated_opts_first;
/* If "opts_root->id" is set, reinstantiate it as a fake QemuOpt for
* uniformity. Only its "name" and "str" fields are set. "fake_id_opt" does
@ -156,9 +165,11 @@ opts_start_list(Visitor *v, const char *name, Error **errp)
OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
/* we can't traverse a list in a list */
assert(ov->repeated_opts == NULL);
assert(ov->list_mode == LM_NONE);
ov->repeated_opts = lookup_distinct(ov, name, errp);
ov->repeated_opts_first = (ov->repeated_opts != NULL);
if (ov->repeated_opts != NULL) {
ov->list_mode = LM_STARTED;
}
}
@ -168,10 +179,13 @@ opts_next_list(Visitor *v, GenericList **list, Error **errp)
OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
GenericList **link;
if (ov->repeated_opts_first) {
ov->repeated_opts_first = false;
switch (ov->list_mode) {
case LM_STARTED:
ov->list_mode = LM_IN_PROGRESS;
link = list;
} else {
break;
case LM_IN_PROGRESS: {
const QemuOpt *opt;
opt = g_queue_pop_head(ov->repeated_opts);
@ -180,6 +194,11 @@ opts_next_list(Visitor *v, GenericList **list, Error **errp)
return NULL;
}
link = &(*list)->next;
break;
}
default:
abort();
}
*link = g_malloc0(sizeof **link);
@ -192,14 +211,16 @@ opts_end_list(Visitor *v, Error **errp)
{
OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
assert(ov->list_mode == LM_STARTED || ov->list_mode == LM_IN_PROGRESS);
ov->repeated_opts = NULL;
ov->list_mode = LM_NONE;
}
static const QemuOpt *
lookup_scalar(const OptsVisitor *ov, const char *name, Error **errp)
{
if (ov->repeated_opts == NULL) {
if (ov->list_mode == LM_NONE) {
GQueue *list;
/* the last occurrence of any QemuOpt takes effect when queried by name
@ -207,6 +228,7 @@ lookup_scalar(const OptsVisitor *ov, const char *name, Error **errp)
list = lookup_distinct(ov, name, errp);
return list ? g_queue_peek_tail(list) : NULL;
}
assert(ov->list_mode == LM_IN_PROGRESS);
return g_queue_peek_head(ov->repeated_opts);
}
@ -214,9 +236,12 @@ lookup_scalar(const OptsVisitor *ov, const char *name, Error **errp)
static void
processed(OptsVisitor *ov, const char *name)
{
if (ov->repeated_opts == NULL) {
if (ov->list_mode == LM_NONE) {
g_hash_table_remove(ov->unprocessed_opts, name);
return;
}
assert(ov->list_mode == LM_IN_PROGRESS);
/* do nothing */
}
@ -365,7 +390,7 @@ opts_start_optional(Visitor *v, bool *present, const char *name,
OptsVisitor *ov = DO_UPCAST(OptsVisitor, visitor, v);
/* we only support a single mandatory scalar field in a list node */
assert(ov->repeated_opts == NULL);
assert(ov->list_mode == LM_NONE);
*present = (lookup_distinct(ov, name, NULL) != NULL);
}