The qdict_flatten() method will take a dict whose elements are
further nested dicts/lists and flatten them by concatenating
keys.
The qdict_crumple() method aims todo the reverse, taking a flat
qdict, and turning it into a set of nested dicts/lists. It will
apply nesting based on the key name, with a '.' indicating a
new level in the hierarchy. If the keys in the nested structure
are all numeric, it will create a list, otherwise it will create
a dict.
If the keys are a mixture of numeric and non-numeric, or the
numeric keys are not in strictly ascending order, an error will
be reported.
As an example, a flat dict containing
{
'foo.0.bar': 'one',
'foo.0.wizz': '1',
'foo.1.bar': 'two',
'foo.1.wizz': '2'
}
will get turned into a dict with one element 'foo' whose
value is a list. The list elements will each in turn be
dicts.
{
'foo' => [
{ 'bar': 'one', 'wizz': '1' }
{ 'bar': 'two', 'wizz': '2' }
],
}
If the key is intended to contain a literal '.', then it must
be escaped as '..'. ie a flat dict
{
'foo..bar': 'wizz',
'bar.foo..bar': 'eek',
'bar.hello': 'world'
}
Will end up as
{
'foo.bar': 'wizz',
'bar': {
'foo.bar': 'eek',
'hello': 'world'
}
}
The intent of this function is that it allows a set of QemuOpts
to be turned into a nested data structure that mirrors the nested
used when the same object is defined over QMP.
Signed-off-by: Daniel P. Berrange <berra...@redhat.com>
---
include/qapi/qmp/qdict.h | 1 +
qobject/qdict.c | 180 +++++++++++++++++++++++++++++++++++++++++++++++
tests/check-qdict.c | 39 ++++++++++
3 files changed, 220 insertions(+)
diff --git a/include/qapi/qmp/qdict.h b/include/qapi/qmp/qdict.h
index 6c2a0e5..baf45d5 100644
--- a/include/qapi/qmp/qdict.h
+++ b/include/qapi/qmp/qdict.h
@@ -75,6 +75,7 @@ void qdict_flatten(QDict *qdict);
void qdict_extract_subqdict(QDict *src, QDict **dst, const char *start);
void qdict_array_split(QDict *src, QList **dst);
int qdict_array_entries(QDict *src, const char *subqdict);
+QObject *qdict_crumple(QDict *src, Error **errp);
void qdict_join(QDict *dest, QDict *src, bool overwrite);
diff --git a/qobject/qdict.c b/qobject/qdict.c
index 9833bd0..ff4caf8 100644
--- a/qobject/qdict.c
+++ b/qobject/qdict.c
@@ -608,6 +608,7 @@ void qdict_extract_subqdict(QDict *src, QDict **dst, const
char *start)
}
}
+
static int qdict_count_prefixed_entries(const QDict *src, const char *start)
{
const QDictEntry *entry;
@@ -682,6 +683,185 @@ void qdict_array_split(QDict *src, QList **dst)
}
}
+
+/**
+ * qdict_crumple:
+ *
+ * Reverses the flattening done by qdict_flatten by
+ * crumpling the dicts into a nested structure. Similar
+ * qdict_array_split, but copes with arbitrary nesting
+ * of dicts & arrays, not meely one level of arrays
+ *
+ * { 'foo.0.bar': 'one', 'foo.0.wizz': '1',
+ * 'foo.1.bar': 'two', 'foo.1.wizz': '2' }
+ *
+ * =>
+ *
+ * {
+ * 'foo' => [
+ * { 'bar': 'one', 'wizz': '1' }
+ * { 'bar': 'two', 'wizz': '2' }
+ * ],
+ * }
+ *
+ */
+QObject *qdict_crumple(QDict *src, Error **errp)
+{
+ const QDictEntry *entry, *next;
+ const char *p = NULL;
+ QDict *tmp1 = NULL, *tmp2 = NULL;
+ QObject *dst = NULL, *child;
+ bool isList = false;
+ ssize_t listMax = -1;
+ size_t listLen = 0;
+ size_t i, j;
+ int64_t val;
+ char *key;
+
+ tmp1 = qdict_new();
+ entry = qdict_first(src);
+
+ /* Step 1: extract everything as nested dicts */
+ while (entry != NULL) {
+ next = qdict_next(src, entry);
+ qobject_incref(entry->value);
+
+ /* Find first '.' separator, but treat '..' as
+ * an escape sequence */
+ p = NULL;
+ do {
+ if (p) {
+ p += 2;
+ } else {
+ p = entry->key;
+ }
+ p = strchr(p, '.');
+ } while (p && *(p + 1) == '.');
+
+ if (p) {
+ key = g_strndup(entry->key,
+ p - entry->key);
+ } else {
+ key = g_strdup(entry->key);
+ }
+
+ for (i = 0, j = 0; key[i] != '\0'; i++, j++) {
+ if (key[i] == '.' &&
+ key[i + 1] == '.') {
+ i++;
+ }
+ key[j] = key[i];
+ }
+ key[j] = '\0';
+
+ if (p) {
+ tmp2 = qdict_get_qdict(tmp1, key);
+ p++;
+ if (!tmp2) {
+ tmp2 = qdict_new();
+ qdict_put(tmp1, key, tmp2);
+ }
+ qdict_put_obj(tmp2, p, entry->value);
+ } else {
+ qdict_put_obj(tmp1, key, entry->value);
+ }
+
+ entry = next;
+ }
+
+ /* Step 2: crumple the new dicts we just created */
+ tmp2 = qdict_new();
+ entry = qdict_first(tmp1);
+ while (entry != NULL) {
+ next = qdict_next(tmp1, entry);
+
+ if (qobject_type(entry->value) == QTYPE_QDICT) {
+ child = qdict_crumple((QDict *)entry->value, errp);
+ if (!child) {
+ goto error;
+ }
+
+ qdict_put_obj(tmp2, entry->key, child);
+ } else {
+ qobject_incref(entry->value);
+ qdict_put_obj(tmp2, entry->key, entry->value);
+ }
+
+ entry = next;
+ }
+ QDECREF(tmp1);
+
+ /* Step 3: detect if we need to turn our dict into list */
+ entry = qdict_first(tmp2);
+ while (entry != NULL) {
+ next = qdict_next(tmp2, entry);
+
+ errno = 0;
+ if (qemu_strtoll(entry->key, NULL, 10, &val) == 0) {
+ if (!dst) {
+ dst = (QObject *)qlist_new();
+ isList = true;
+ } else if (!isList) {
+ error_setg(errp,
+ "Key '%s' is for a list, but previous key is "
+ "for a dict", entry->key);
+ goto error;
+ }
+ listLen++;
+ if (val > listMax) {
+ listMax = val;
+ }
+ } else {
+ if (!dst) {
+ dst = (QObject *)tmp2;
+ qobject_incref(dst);
+ isList = false;
+ } else if (isList) {
+ error_setg(errp,
+ "Key '%s' is for a dict, but previous key is "
+ "for a list", entry->key);
+ goto error;
+ }
+ }
+
+ entry = next;
+ }
+
+ /* Step 4: Turn the dict into a list */
+ if (isList) {
+ if (listLen != (listMax + 1)) {
+ error_setg(errp, "List indexes are not continuous, "
+ "saw %zu elements but %zu largest index",
+ listLen, listMax);
+ goto error;
+ }
+
+ for (i = 0; i < listLen; i++) {
+ char *key = g_strdup_printf("%zu", i);
+
+ child = qdict_get(tmp2, key);
+ g_free(key);
+ if (!child) {
+ error_setg(errp, "Unexpected missing list entry %zu", i);
+ goto error;
+ }
+
+ qobject_incref(child);
+ qlist_append_obj((QList *)dst, child);
+ }
+ }
+ QDECREF(tmp2);
+
+ return dst;
+
+ error:
+ QDECREF(tmp2);
+ QDECREF(tmp1);
+ qobject_decref(dst);
+ return NULL;
+}
+
+
/**
* 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
diff --git a/tests/check-qdict.c b/tests/check-qdict.c
index a43056c..fb8184c 100644
--- a/tests/check-qdict.c
+++ b/tests/check-qdict.c
@@ -596,6 +596,43 @@ static void qdict_join_test(void)
QDECREF(dict2);
}
+
+static void qdict_crumple_test(void)
+{
+ QDict *src, *dst, *rule, *eek;
+ QList *rules;
+
+ src = qdict_new();
+ qdict_put(src, "rule.0.match", qstring_from_str("fred"));
+ qdict_put(src, "rule.0.policy", qstring_from_str("allow"));
+ qdict_put(src, "rule.1.match", qstring_from_str("bob"));
+ qdict_put(src, "rule.1.policy", qstring_from_str("deny"));
+ qdict_put(src, "foo..bar", qstring_from_str("wibble"));
+ qdict_put(src, "eek.foo..bar", qstring_from_str("wizz"));
+
+ dst = (QDict *)qdict_crumple(src, &error_abort);
+
+ g_assert_cmpint(qdict_size(dst), ==, 3);
+
+ rules = qdict_get_qlist(dst, "rule");
+
+ g_assert_cmpint(qlist_size(rules), ==, 2);
+
+ rule = qobject_to_qdict(qlist_pop(rules));
+ g_assert_cmpstr("fred", ==, qdict_get_str(rule, "match"));
+ g_assert_cmpstr("allow", ==, qdict_get_str(rule, "policy"));
+
+ rule = qobject_to_qdict(qlist_pop(rules));
+ g_assert_cmpstr("bob", ==, qdict_get_str(rule, "match"));
+ g_assert_cmpstr("deny", ==, qdict_get_str(rule, "policy"));
+
+ g_assert_cmpstr("wibble", ==, qdict_get_str(dst, "foo.bar"));
+
+ eek = qdict_get_qdict(dst, "eek");
+ g_assert_cmpstr("wizz", ==, qdict_get_str(eek, "foo.bar"));
+}
+
+
/*
* Errors test-cases
*/
@@ -743,6 +780,8 @@ int main(int argc, char **argv)
g_test_add_func("/errors/put_exists", qdict_put_exists_test);
g_test_add_func("/errors/get_not_exists", qdict_get_not_exists_test);
+ g_test_add_func("/public/crumple", qdict_crumple_test);
+
/* The Big one */
if (g_test_slow()) {
g_test_add_func("/stress/test", qdict_stress_test);
--
2.5.0
