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authorKevin Wolf <kwolf@redhat.com>2015-01-21 17:15:44 +0100
committerKevin Wolf <kwolf@redhat.com>2015-06-12 16:58:06 +0200
commitbd50530a9f40f6560a03caeaaddd451e2ce90ed8 (patch)
treebe6ecbd04757b119babeaa7e94ea205de7730fe6 /qobject/qdict.c
parenta68197ff5b11f5a58d48e485d16a36758aeca7f4 (diff)
qdict: Add qdict_array_entries()
This counts the entries in a flattened array in a QDict without actually splitting the QDict into a QList. bdrv_open_image() doesn't take a QList, but rather a QDict and a key prefix string, so this is more convenient for block drivers which have a dynamically sized list of child nodes (e.g. Quorum) and are to be converted to using bdrv_open_image() as the standard interface for opening child nodes. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'qobject/qdict.c')
-rw-r--r--qobject/qdict.c78
1 files changed, 74 insertions, 4 deletions
diff --git a/qobject/qdict.c b/qobject/qdict.c
index ea239f082e..50c0ab378b 100644
--- a/qobject/qdict.c
+++ b/qobject/qdict.c
@@ -597,17 +597,21 @@ void qdict_extract_subqdict(QDict *src, QDict **dst, const char *start)
}
}
-static bool qdict_has_prefixed_entries(const QDict *src, const char *start)
+static int qdict_count_prefixed_entries(const QDict *src, const char *start)
{
const QDictEntry *entry;
+ int count = 0;
for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
if (strstart(entry->key, start, NULL)) {
- return true;
+ if (count == INT_MAX) {
+ return -ERANGE;
+ }
+ count++;
}
}
- return false;
+ return count;
}
/**
@@ -646,7 +650,8 @@ void qdict_array_split(QDict *src, QList **dst)
snprintf_ret = snprintf(prefix, 32, "%u.", i);
assert(snprintf_ret < 32);
- is_subqdict = qdict_has_prefixed_entries(src, prefix);
+ /* Overflow is the same as positive non-zero results */
+ is_subqdict = qdict_count_prefixed_entries(src, prefix);
// There may be either a single subordinate object (named "%u") or
// multiple objects (each with a key prefixed "%u."), but not both.
@@ -667,6 +672,71 @@ void qdict_array_split(QDict *src, QList **dst)
}
/**
+ * qdict_array_entries(): Returns the number of direct array entries if the
+ * sub-QDict of src specified by the prefix in subqdict (or src itself for
+ * prefix == "") is valid as an array, i.e. the length of the created list if
+ * the sub-QDict would become empty after calling qdict_array_split() on it. If
+ * the array is not valid, -EINVAL is returned.
+ */
+int qdict_array_entries(QDict *src, const char *subqdict)
+{
+ const QDictEntry *entry;
+ unsigned i;
+ unsigned entries = 0;
+ size_t subqdict_len = strlen(subqdict);
+
+ assert(!subqdict_len || subqdict[subqdict_len - 1] == '.');
+
+ /* qdict_array_split() loops until UINT_MAX, but as we want to return
+ * negative errors, we only have a signed return value here. Any additional
+ * entries will lead to -EINVAL. */
+ for (i = 0; i < INT_MAX; i++) {
+ QObject *subqobj;
+ int subqdict_entries;
+ size_t slen = 32 + subqdict_len;
+ char indexstr[slen], prefix[slen];
+ size_t snprintf_ret;
+
+ snprintf_ret = snprintf(indexstr, slen, "%s%u", subqdict, i);
+ assert(snprintf_ret < slen);
+
+ subqobj = qdict_get(src, indexstr);
+
+ snprintf_ret = snprintf(prefix, slen, "%s%u.", subqdict, i);
+ assert(snprintf_ret < slen);
+
+ subqdict_entries = qdict_count_prefixed_entries(src, prefix);
+ if (subqdict_entries < 0) {
+ return subqdict_entries;
+ }
+
+ /* There may be either a single subordinate object (named "%u") or
+ * multiple objects (each with a key prefixed "%u."), but not both. */
+ if (subqobj && subqdict_entries) {
+ return -EINVAL;
+ } else if (!subqobj && !subqdict_entries) {
+ break;
+ }
+
+ entries += subqdict_entries ? subqdict_entries : 1;
+ }
+
+ /* Consider everything handled that isn't part of the given sub-QDict */
+ for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
+ if (!strstart(qdict_entry_key(entry), subqdict, NULL)) {
+ entries++;
+ }
+ }
+
+ /* Anything left in the sub-QDict that wasn't handled? */
+ if (qdict_size(src) != entries) {
+ return -EINVAL;
+ }
+
+ return i;
+}
+
+/**
* qdict_join(): Absorb the src QDict into the dest QDict, that is, move all
* elements from src to dest.
*