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[Qemu-devel] [PATCH v12 04/18] qmp-input: Clean up stack handling
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PATCH v12 04/18] qmp-input: Clean up stack handling |
Date: |
Mon, 29 Feb 2016 22:14:18 -0700 |
Management of the top of stack was a bit verbose; creating a
temporary variable and adding some comments makes the existing
code more legible before the next few patches improve things.
No semantic changes other than asserting that we are always
visiting a QObject, and not a NULL value.
Signed-off-by: Eric Blake <address@hidden>
---
v12: new patch
---
qapi/qmp-input-visitor.c | 52 ++++++++++++++++++++++++++++++++++--------------
1 file changed, 37 insertions(+), 15 deletions(-)
diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c
index 550aed6..7428d15 100644
--- a/qapi/qmp-input-visitor.c
+++ b/qapi/qmp-input-visitor.c
@@ -24,16 +24,26 @@
typedef struct StackObject
{
- QObject *obj;
+ QObject *obj; /* Object being visited */
+
+ /* If obj is list: NULL if list is at head, otherwise tail of list
+ * still needing visits */
const QListEntry *entry;
- GHashTable *h;
+
+ GHashTable *h; /* If obj is dict: remaining keys needing visits */
} StackObject;
struct QmpInputVisitor
{
Visitor visitor;
+
+ /* Stack of objects being visited. stack[0] is root of visit,
+ * stack[1] and below correspond to visit_start_struct (nested
+ * QDict) and visit_start_list (nested QList). */
StackObject stack[QIV_STACK_SIZE];
int nb_stack;
+
+ /* True to track whether all keys in QDict have been parsed. */
bool strict;
};
@@ -46,19 +56,29 @@ static QObject *qmp_input_get_object(QmpInputVisitor *qiv,
const char *name,
bool consume)
{
- QObject *qobj = qiv->stack[qiv->nb_stack - 1].obj;
+ StackObject *tos = &qiv->stack[qiv->nb_stack - 1];
+ QObject *qobj = tos->obj;
- if (qobj) {
- if (name && qobject_type(qobj) == QTYPE_QDICT) {
- if (qiv->stack[qiv->nb_stack - 1].h && consume) {
- g_hash_table_remove(qiv->stack[qiv->nb_stack - 1].h, name);
- }
- return qdict_get(qobject_to_qdict(qobj), name);
- } else if (qiv->stack[qiv->nb_stack - 1].entry) {
- return qlist_entry_obj(qiv->stack[qiv->nb_stack - 1].entry);
+ assert(qobj);
+
+ /* If we have a name, and we're in a dictionary, then return that
+ * value. */
+ if (name && qobject_type(qobj) == QTYPE_QDICT) {
+ if (tos->h && consume) {
+ g_hash_table_remove(tos->h, name);
}
+ return qdict_get(qobject_to_qdict(qobj), name);
}
+ /* If we are in the middle of a list, then return the next element
+ * of the list. */
+ if (tos->entry) {
+ assert(qobject_type(qobj) == QTYPE_QLIST);
+ return qlist_entry_obj(tos->entry);
+ }
+
+ /* Otherwise, we are at the root of the visit or the start of a
+ * list, and return the object as-is. */
return qobj;
}
@@ -71,20 +91,22 @@ static void qdict_add_key(const char *key, QObject *obj,
void *opaque)
static void qmp_input_push(QmpInputVisitor *qiv, QObject *obj, Error **errp)
{
GHashTable *h;
+ StackObject *tos = &qiv->stack[qiv->nb_stack];
+ assert(obj);
if (qiv->nb_stack >= QIV_STACK_SIZE) {
error_setg(errp, "An internal buffer overran");
return;
}
- qiv->stack[qiv->nb_stack].obj = obj;
- qiv->stack[qiv->nb_stack].entry = NULL;
- qiv->stack[qiv->nb_stack].h = NULL;
+ tos->obj = obj;
+ tos->entry = NULL;
+ tos->h = NULL;
if (qiv->strict && qobject_type(obj) == QTYPE_QDICT) {
h = g_hash_table_new(g_str_hash, g_str_equal);
qdict_iter(qobject_to_qdict(obj), qdict_add_key, h);
- qiv->stack[qiv->nb_stack].h = h;
+ tos->h = h;
}
qiv->nb_stack++;
--
2.5.0
- [Qemu-devel] [PATCH v12 03/18] qmp: Drop dead command->type, (continued)
- [Qemu-devel] [PATCH v12 03/18] qmp: Drop dead command->type, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 01/18] qapi-visit: Add visitor.type classification, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 10/18] qmp: Support explicit null during visits, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 05/18] qmp-input: Don't consume input when checking has_member, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 07/18] qapi: Document visitor interfaces, add assertions, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 02/18] qapi: Guarantee NULL obj on input visitor callback error, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 12/18] qmp: Tighten output visitor rules, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 14/18] qapi-commands: Wrap argument visit in visit_start_struct, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 15/18] qom: Wrap prop visit in visit_start_struct, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 16/18] qmp-input: Require struct push to visit members of top dict, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 04/18] qmp-input: Clean up stack handling,
Eric Blake <=
- [Qemu-devel] [PATCH v12 08/18] tests: Add check-qnull, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 11/18] spapr_drc: Expose 'null' in qom-get when there is no fdt, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 13/18] qapi: Split visit_end_struct() into pieces, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 18/18] qapi: Change visit_type_FOO() to no longer return partial objects, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 09/18] qapi: Add visit_type_null() visitor, Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 17/18] qapi: Simplify semantics of visit_next_list(), Eric Blake, 2016/03/01
- [Qemu-devel] [PATCH v12 06/18] qmp-input: Refactor when list is advanced, Eric Blake, 2016/03/01