Commit d9570434 authored by Laszlo Ersek's avatar Laszlo Ersek Committed by Luiz Capitulino
Browse files

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: default avatarLaszlo Ersek <lersek@redhat.com>
Tested-by: default avatarWanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: default avatarLuiz Capitulino <lcapitulino@redhat.com>
parent 4a44d85e

qapi/opts-visitor.c

+35 −10
Original line number Diff line number Diff line 
/*

 * 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);

}