From 9812e7125b83ba6e4645237150ca5f61bf66197f Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Tue, 27 Oct 2020 00:05:47 -0500 Subject: [PATCH] qapi: Add QAPI_LIST_PREPEND() macro block.c has a useful macro QAPI_LIST_ADD() for inserting at the front of any QAPI-generated list; move it from block.c to qapi/util.h so more places can use it, including one earlier place in block.c, and rename it to something more obvious (since we also have a lot of places that append, rather than prepend, to a list). There are many more places in the codebase that can benefit from using the macro, but converting them will be left to later patches. In theory, all QAPI list types are child classes of GenericList; but in practice, that relationship is not explicitly spelled out in the C type declarations (rather, it is something that happens implicitly due to C compatible layouts), and the macro does not actually depend on the GenericList type. We considered moving GenericList from visitor.h into util.h to group related code; however, such a move would be awkward if we do not also move GenericAlternate. Unfortunately, moving GenericAlternate would introduce its own problems of declaration circularity (qapi-builtin-types.h needs a complete definition of QEnumLookup from util.h, but GenericAlternate needs a complete definition of QType from qapi-builtin-types.h). Suggested-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Markus Armbruster Message-Id: <20201027050556.269064-3-eblake@redhat.com> [eblake: s/ADD/PREPEND/ per suggestion by Markus] --- block.c | 22 ++++++---------------- include/qapi/util.h | 13 +++++++++++++ 2 files changed, 19 insertions(+), 16 deletions(-) diff --git a/block.c b/block.c index dd551d7ea9..56bacc9e9f 100644 --- a/block.c +++ b/block.c @@ -5220,7 +5220,7 @@ BlockDriverState *bdrv_find_node(const char *node_name) BlockDeviceInfoList *bdrv_named_nodes_list(bool flat, Error **errp) { - BlockDeviceInfoList *list, *entry; + BlockDeviceInfoList *list; BlockDriverState *bs; list = NULL; @@ -5230,22 +5230,12 @@ BlockDeviceInfoList *bdrv_named_nodes_list(bool flat, qapi_free_BlockDeviceInfoList(list); return NULL; } - entry = g_malloc0(sizeof(*entry)); - entry->value = info; - entry->next = list; - list = entry; + QAPI_LIST_PREPEND(list, info); } return list; } -#define QAPI_LIST_ADD(list, element) do { \ - typeof(list) _tmp = g_malloc(sizeof(*(list))); \ - _tmp->value = (element); \ - _tmp->next = (list); \ - (list) = _tmp; \ -} while (0) - typedef struct XDbgBlockGraphConstructor { XDbgBlockGraph *graph; GHashTable *graph_nodes; @@ -5300,7 +5290,7 @@ static void xdbg_graph_add_node(XDbgBlockGraphConstructor *gr, void *node, n->type = type; n->name = g_strdup(name); - QAPI_LIST_ADD(gr->graph->nodes, n); + QAPI_LIST_PREPEND(gr->graph->nodes, n); } static void xdbg_graph_add_edge(XDbgBlockGraphConstructor *gr, void *parent, @@ -5319,14 +5309,14 @@ static void xdbg_graph_add_edge(XDbgBlockGraphConstructor *gr, void *parent, uint64_t flag = bdrv_qapi_perm_to_blk_perm(qapi_perm); if (flag & child->perm) { - QAPI_LIST_ADD(edge->perm, qapi_perm); + QAPI_LIST_PREPEND(edge->perm, qapi_perm); } if (flag & child->shared_perm) { - QAPI_LIST_ADD(edge->shared_perm, qapi_perm); + QAPI_LIST_PREPEND(edge->shared_perm, qapi_perm); } } - QAPI_LIST_ADD(gr->graph->edges, edge); + QAPI_LIST_PREPEND(gr->graph->edges, edge); } diff --git a/include/qapi/util.h b/include/qapi/util.h index a7c3c64148..bc312e90aa 100644 --- a/include/qapi/util.h +++ b/include/qapi/util.h @@ -22,4 +22,17 @@ int qapi_enum_parse(const QEnumLookup *lookup, const char *buf, int parse_qapi_name(const char *name, bool complete); +/* + * For any GenericList @list, insert @element at the front. + * + * Note that this macro evaluates @element exactly once, so it is safe + * to have side-effects with that argument. + */ +#define QAPI_LIST_PREPEND(list, element) do { \ + typeof(list) _tmp = g_malloc(sizeof(*(list))); \ + _tmp->value = (element); \ + _tmp->next = (list); \ + (list) = _tmp; \ +} while (0) + #endif -- 2.11.4.GIT