*
* Semantics defined by reduction to JSON:
*
- * key-vals defines a tree of objects rooted at R
- * where for each key-val = key-fragment . ... = val in key-vals
- * R op key-fragment op ... = val'
- * where (left-associative) op is member reference L.key-fragment
- * val' is val with ',,' replaced by ','
- * and only R may be empty.
+ * key-vals specifies a JSON object, i.e. a tree whose root is an
+ * object, inner nodes other than the root are objects or arrays,
+ * and leaves are strings.
*
- * Duplicate keys are permitted; all but the last one are ignored.
+ * Each key-val = key-fragment '.' ... '=' val specifies a path from
+ * root to a leaf (left of '='), and the leaf's value (right of
+ * '=').
*
- * The equations must have a solution. Counter-example: a.b=1,a=2
- * doesn't have one, because R.a must be an object to satisfy a.b=1
- * and a string to satisfy a=2.
+ * A path from the root is defined recursively:
+ * L '.' key-fragment is a child of the node denoted by path L
+ * key-fragment is a child of the tree root
+ * If key-fragment is numeric, the parent is an array and the child
+ * is its key-fragment-th member, counting from zero.
+ * Else, the parent is an object, and the child is its member named
+ * key-fragment.
+ *
+ * This constrains inner nodes to be either array or object. The
+ * constraints must be satisfiable. Counter-example: a.b=1,a=2 is
+ * not, because root.a must be an object to satisfy a.b=1 and a
+ * string to satisfy a=2.
+ *
+ * Array subscripts can occur in any order, but the set of
+ * subscripts must not have gaps. For instance, a.1=v is not okay,
+ * because root.a[0] is missing.
+ *
+ * If multiple key-val denote the same leaf, the last one determines
+ * the value.
+ *
+ * Key-fragments must be valid QAPI names or consist only of decimal
+ * digits.
*
* The length of any key-fragment must be between 1 and 127.
*
- * Design flaw: there is no way to denote an empty non-root object.
- * While interpreting "key absent" as empty object seems natural
+ * Design flaw: there is no way to denote an empty array or non-root
+ * object. While interpreting "key absent" as empty seems natural
* (removing a key-val from the input string removes the member when
* there are more, so why not when it's the last), it doesn't work:
- * "key absent" already means "optional object absent", which isn't
- * the same as "empty object present".
+ * "key absent" already means "optional object/array absent", which
+ * isn't the same as "empty object/array present".
+ *
+ * Design flaw: scalar values can only be strings; there is no way to
+ * denote numbers, true, false or null. The special QObject input
+ * visitor returned by qobject_input_visitor_new_keyval() mostly hides
+ * this by automatically converting strings to the type the visitor
+ * expects. Breaks down for type 'any', where the visitor's
+ * expectation isn't clear. Code visiting 'any' needs to do the
+ * conversion itself, but only when using this keyval visitor.
+ * Awkward. Note that we carefully restrict alternate types to avoid
+ * similar ambiguity.
*
* Additional syntax for use with an implied key:
*
* val-no-key = / [^=,]* /
*
* where no-key is syntactic sugar for implied-key=val-no-key.
- *
- * TODO support lists
- * TODO support key-fragment with __RFQDN_ prefix (downstream extensions)
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qlist.h"
#include "qapi/qmp/qstring.h"
+#include "qemu/cutils.h"
#include "qemu/option.h"
+/*
+ * Convert @key to a list index.
+ * Convert all leading decimal digits to a (non-negative) number,
+ * capped at INT_MAX.
+ * If @end is non-null, assign a pointer to the first character after
+ * the number to *@end.
+ * Else, fail if any characters follow.
+ * On success, return the converted number.
+ * On failure, return a negative value.
+ * Note: since only digits are converted, no two keys can map to the
+ * same number, except by overflow to INT_MAX.
+ */
+static int key_to_index(const char *key, const char **end)
+{
+ int ret;
+ unsigned long index;
+
+ if (*key < '0' || *key > '9') {
+ return -EINVAL;
+ }
+ ret = qemu_strtoul(key, end, 10, &index);
+ if (ret) {
+ return ret == -ERANGE ? INT_MAX : ret;
+ }
+ return index <= INT_MAX ? index : INT_MAX;
+}
+
/*
* Ensure @cur maps @key_in_cur the right way.
* If @value is null, it needs to map to a QDict, else to this
* Else, fail because we have conflicting needs on how to map
* @key_in_cur.
* In any case, take over the reference to @value, i.e. if the caller
- * wants to hold on to a reference, it needs to QINCREF().
+ * wants to hold on to a reference, it needs to qobject_ref().
* Use @key up to @key_cursor to identify the key in error messages.
* On success, return the mapped value.
* On failure, store an error through @errp and return NULL.
if (qobject_type(old) != (value ? QTYPE_QSTRING : QTYPE_QDICT)) {
error_setg(errp, "Parameters '%.*s.*' used inconsistently",
(int)(key_cursor - key), key);
- QDECREF(value);
+ qobject_unref(value);
return NULL;
}
if (!value) {
const char *implied_key,
Error **errp)
{
- const char *key, *key_end, *s;
+ const char *key, *key_end, *s, *end;
size_t len;
char key_in_cur[128];
QDict *cur;
+ int ret;
QObject *next;
QString *val;
cur = qdict;
s = key;
for (;;) {
- for (len = 0; s + len < key_end && s[len] != '.'; len++) {
+ /* Want a key index (unless it's first) or a QAPI name */
+ if (s != key && key_to_index(s, &end) >= 0) {
+ len = end - s;
+ } else {
+ ret = parse_qapi_name(s, false);
+ len = ret < 0 ? 0 : ret;
}
- if (!len) {
+ assert(s + len <= key_end);
+ if (!len || (s + len < key_end && s[len] != '.')) {
assert(key != implied_key);
error_setg(errp, "Invalid parameter '%.*s'",
(int)(key_end - key), key);
if (!next) {
return NULL;
}
- cur = qobject_to_qdict(next);
+ cur = qobject_to(QDict, next);
assert(cur);
}
return s;
}
+static char *reassemble_key(GSList *key)
+{
+ GString *s = g_string_new("");
+ GSList *p;
+
+ for (p = key; p; p = p->next) {
+ g_string_prepend_c(s, '.');
+ g_string_prepend(s, (char *)p->data);
+ }
+
+ return g_string_free(s, FALSE);
+}
+
+/*
+ * Listify @cur recursively.
+ * Replace QDicts whose keys are all valid list indexes by QLists.
+ * @key_of_cur is the list of key fragments leading up to @cur.
+ * On success, return either @cur or its replacement.
+ * On failure, store an error through @errp and return NULL.
+ */
+static QObject *keyval_listify(QDict *cur, GSList *key_of_cur, Error **errp)
+{
+ GSList key_node;
+ bool has_index, has_member;
+ const QDictEntry *ent;
+ QDict *qdict;
+ QObject *val;
+ char *key;
+ size_t nelt;
+ QObject **elt;
+ int index, max_index, i;
+ QList *list;
+
+ key_node.next = key_of_cur;
+
+ /*
+ * Recursively listify @cur's members, and figure out whether @cur
+ * itself is to be listified.
+ */
+ has_index = false;
+ has_member = false;
+ for (ent = qdict_first(cur); ent; ent = qdict_next(cur, ent)) {
+ if (key_to_index(ent->key, NULL) >= 0) {
+ has_index = true;
+ } else {
+ has_member = true;
+ }
+
+ qdict = qobject_to(QDict, ent->value);
+ if (!qdict) {
+ continue;
+ }
+
+ key_node.data = ent->key;
+ val = keyval_listify(qdict, &key_node, errp);
+ if (!val) {
+ return NULL;
+ }
+ if (val != ent->value) {
+ qdict_put_obj(cur, ent->key, val);
+ }
+ }
+
+ if (has_index && has_member) {
+ key = reassemble_key(key_of_cur);
+ error_setg(errp, "Parameters '%s*' used inconsistently", key);
+ g_free(key);
+ return NULL;
+ }
+ if (!has_index) {
+ return QOBJECT(cur);
+ }
+
+ /* Copy @cur's values to @elt[] */
+ nelt = qdict_size(cur) + 1; /* one extra, for use as sentinel */
+ elt = g_new0(QObject *, nelt);
+ max_index = -1;
+ for (ent = qdict_first(cur); ent; ent = qdict_next(cur, ent)) {
+ index = key_to_index(ent->key, NULL);
+ assert(index >= 0);
+ if (index > max_index) {
+ max_index = index;
+ }
+ /*
+ * We iterate @nelt times. If we get one exceeding @nelt
+ * here, we will put less than @nelt values into @elt[],
+ * triggering the error in the next loop.
+ */
+ if ((size_t)index >= nelt - 1) {
+ continue;
+ }
+ /* Even though dict keys are distinct, indexes need not be */
+ elt[index] = ent->value;
+ }
+
+ /*
+ * Make a list from @elt[], reporting the first missing element,
+ * if any.
+ * If we dropped an index >= nelt in the previous loop, this loop
+ * will run into the sentinel and report index @nelt missing.
+ */
+ list = qlist_new();
+ assert(!elt[nelt-1]); /* need the sentinel to be null */
+ for (i = 0; i < MIN(nelt, max_index + 1); i++) {
+ if (!elt[i]) {
+ key = reassemble_key(key_of_cur);
+ error_setg(errp, "Parameter '%s%d' missing", key, i);
+ g_free(key);
+ g_free(elt);
+ qobject_unref(list);
+ return NULL;
+ }
+ qobject_ref(elt[i]);
+ qlist_append_obj(list, elt[i]);
+ }
+
+ g_free(elt);
+ return QOBJECT(list);
+}
+
/*
* Parse @params in QEMU's traditional KEY=VALUE,... syntax.
* If @implied_key, the first KEY= can be omitted. @implied_key is
Error **errp)
{
QDict *qdict = qdict_new();
+ QObject *listified;
const char *s;
s = params;
while (*s) {
s = keyval_parse_one(qdict, s, implied_key, errp);
if (!s) {
- QDECREF(qdict);
+ qobject_unref(qdict);
return NULL;
}
implied_key = NULL;
}
+ listified = keyval_listify(qdict, NULL, errp);
+ if (!listified) {
+ qobject_unref(qdict);
+ return NULL;
+ }
+ assert(listified == QOBJECT(qdict));
return qdict;
}
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