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[PATCH v2 02/11] keyval: introduce keyval_merge
From: |
Paolo Bonzini |
Subject: |
[PATCH v2 02/11] keyval: introduce keyval_merge |
Date: |
Thu, 17 Jun 2021 17:52:59 +0200 |
This patch introduces a function that merges two keyval-produced
(or keyval-like) QDicts. It can be used to emulate the behavior of
.merge_lists = true QemuOpts groups, merging -readconfig sections and
command-line options in a single QDict, and also to implement -set.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
include/qemu/option.h | 1 +
tests/unit/test-keyval.c | 58 ++++++++++++++++++++++++++++++++
util/keyval.c | 71 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 130 insertions(+)
diff --git a/include/qemu/option.h b/include/qemu/option.h
index f73e0dc7d9..d89c66145a 100644
--- a/include/qemu/option.h
+++ b/include/qemu/option.h
@@ -149,5 +149,6 @@ QemuOptsList *qemu_opts_append(QemuOptsList *dst,
QemuOptsList *list);
QDict *keyval_parse(const char *params, const char *implied_key,
bool *help, Error **errp);
+void keyval_merge(QDict *old, const QDict *new, Error **errp);
#endif
diff --git a/tests/unit/test-keyval.c b/tests/unit/test-keyval.c
index e20c07cf3e..af0581ae6c 100644
--- a/tests/unit/test-keyval.c
+++ b/tests/unit/test-keyval.c
@@ -747,6 +747,61 @@ static void test_keyval_visit_any(void)
visit_free(v);
}
+static void test_keyval_merge_dict(void)
+{
+ QDict *first =
keyval_parse("opt1=abc,opt2.sub1=def,opt2.sub2=ghi,opt3=xyz",
+ NULL, NULL, &error_abort);
+ QDict *second = keyval_parse("opt1=ABC,opt2.sub2=GHI,opt2.sub3=JKL",
+ NULL, NULL, &error_abort);
+ QDict *combined =
keyval_parse("opt1=ABC,opt2.sub1=def,opt2.sub2=GHI,opt2.sub3=JKL,opt3=xyz",
+ NULL, NULL, &error_abort);
+ Error *err = NULL;
+
+ keyval_merge(first, second, &err);
+ g_assert(!err);
+ g_assert(qobject_is_equal(QOBJECT(combined), QOBJECT(first)));
+ qobject_unref(first);
+ qobject_unref(second);
+ qobject_unref(combined);
+}
+
+static void test_keyval_merge_list(void)
+{
+ QDict *first = keyval_parse("opt1.0=abc,opt2.0=xyz",
+ NULL, NULL, &error_abort);
+ QDict *second = keyval_parse("opt1.0=def",
+ NULL, NULL, &error_abort);
+ QDict *combined = keyval_parse("opt1.0=abc,opt1.1=def,opt2.0=xyz",
+ NULL, NULL, &error_abort);
+ Error *err = NULL;
+
+ keyval_merge(first, second, &err);
+ g_assert(!err);
+ g_assert(qobject_is_equal(QOBJECT(combined), QOBJECT(first)));
+ qobject_unref(first);
+ qobject_unref(second);
+ qobject_unref(combined);
+}
+
+static void test_keyval_merge_conflict(void)
+{
+ QDict *first = keyval_parse("opt2=ABC",
+ NULL, NULL, &error_abort);
+ QDict *second = keyval_parse("opt2.sub1=def,opt2.sub2=ghi",
+ NULL, NULL, &error_abort);
+ QDict *third = qdict_clone_shallow(first);
+ Error *err = NULL;
+
+ keyval_merge(first, second, &err);
+ error_free_or_abort(&err);
+ keyval_merge(second, third, &err);
+ error_free_or_abort(&err);
+
+ qobject_unref(first);
+ qobject_unref(second);
+ qobject_unref(third);
+}
+
int main(int argc, char *argv[])
{
g_test_init(&argc, &argv, NULL);
@@ -760,6 +815,9 @@ int main(int argc, char *argv[])
g_test_add_func("/keyval/visit/optional", test_keyval_visit_optional);
g_test_add_func("/keyval/visit/alternate", test_keyval_visit_alternate);
g_test_add_func("/keyval/visit/any", test_keyval_visit_any);
+ g_test_add_func("/keyval/merge/dict", test_keyval_merge_dict);
+ g_test_add_func("/keyval/merge/list", test_keyval_merge_list);
+ g_test_add_func("/keyval/merge/conflict", test_keyval_merge_conflict);
g_test_run();
return 0;
}
diff --git a/util/keyval.c b/util/keyval.c
index be34928813..8006c5df20 100644
--- a/util/keyval.c
+++ b/util/keyval.c
@@ -310,6 +310,77 @@ static char *reassemble_key(GSList *key)
return g_string_free(s, FALSE);
}
+/*
+ * Recursive worker for keyval_merge. @str is the path that led to the
+ * current dictionary, to be used for error messages. It is modified
+ * internally but restored before the function returns.
+ */
+static void keyval_do_merge(QDict *dest, const QDict *merged, GString *str,
Error **errp)
+{
+ size_t save_len = str->len;
+ const QDictEntry *ent;
+ QObject *old_value;
+
+ for (ent = qdict_first(merged); ent; ent = qdict_next(merged, ent)) {
+ old_value = qdict_get(dest, ent->key);
+ if (old_value) {
+ if (qobject_type(old_value) != qobject_type(ent->value)) {
+ error_setg(errp, "Parameter '%s%s' used inconsistently",
str->str, ent->key);
+ return;
+ } else if (qobject_type(ent->value) == QTYPE_QDICT) {
+ /* Merge sub-dictionaries. */
+ g_string_append(str, ent->key);
+ g_string_append_c(str, '.');
+ keyval_do_merge(qobject_to(QDict, old_value),
+ qobject_to(QDict, ent->value),
+ str, errp);
+ g_string_truncate(str, save_len);
+ continue;
+ } else if (qobject_type(ent->value) == QTYPE_QLIST) {
+ /* Append to old list. */
+ QList *old = qobject_to(QList, old_value);
+ QList *new = qobject_to(QList, ent->value);
+ const QListEntry *item;
+ QLIST_FOREACH_ENTRY(new, item) {
+ qobject_ref(item->value);
+ qlist_append_obj(old, item->value);
+ }
+ continue;
+ } else {
+ assert(qobject_type(ent->value) == QTYPE_QSTRING);
+ }
+ }
+
+ qobject_ref(ent->value);
+ qdict_put_obj(dest, ent->key, ent->value);
+ }
+}
+
+/* Merge the @merged dictionary into @dest. The dictionaries are expected to
be
+ * returned by the keyval parser, and therefore the only expected scalar type
+ * is the * string. In case the same path is present in both @dest and
@merged,
+ * the semantics are as follows:
+ *
+ * - lists are concatenated
+ *
+ * - dictionaries are merged recursively
+ *
+ * - for scalar values, @merged wins
+ *
+ * In case an error is reported, @dest may already have been modified.
+ *
+ * This function can be used to implement semantics analogous to QemuOpts's
+ * .merge_lists = true case, or to implement -set for options backed by QDicts.
+ */
+void keyval_merge(QDict *dest, const QDict *merged, Error **errp)
+{
+ GString *str;
+
+ str = g_string_new("");
+ keyval_do_merge(dest, merged, str, errp);
+ g_string_free(str, TRUE);
+}
+
/*
* Listify @cur recursively.
* Replace QDicts whose keys are all valid list indexes by QLists.
--
2.31.1
- [PATCH v2 00/11] vl: compound properties for machines, Paolo Bonzini, 2021/06/17
- [PATCH v2 03/11] keyval: introduce keyval_parse_into, Paolo Bonzini, 2021/06/17
- [PATCH v2 01/11] qom: export more functions for use with non-UserCreatable objects, Paolo Bonzini, 2021/06/17
- [PATCH v2 02/11] keyval: introduce keyval_merge,
Paolo Bonzini <=
- [PATCH v2 05/11] qemu-option: remove now-dead code, Paolo Bonzini, 2021/06/17
- [PATCH v2 09/11] machine: pass QAPI struct to mc->smp_parse, Paolo Bonzini, 2021/06/17
- [PATCH v2 04/11] vl: switch -M parsing to keyval, Paolo Bonzini, 2021/06/17
- [PATCH v2 06/11] machine: move dies from X86MachineState to CpuTopology, Paolo Bonzini, 2021/06/17
- [PATCH v2 07/11] machine: move common smp_parse code to caller, Paolo Bonzini, 2021/06/17
- [PATCH v2 11/11] machine: add smp compound property, Paolo Bonzini, 2021/06/17
- [PATCH v2 08/11] machine: add error propagation to mc->smp_parse, Paolo Bonzini, 2021/06/17
- [PATCH v2 10/11] machine: reject -smp dies!=1 for non-PC machines, Paolo Bonzini, 2021/06/17
- Re: [PATCH v2 00/11] vl: compound properties for machines, no-reply, 2021/06/17