[ovs-dev] [mointor2 2/9] lib: avoid set size check when generating diff datum from json

[Andy Zhou]

Added ovsdb_transient_datum_from_json() to avoid size check for
the diff datum that is transient in nature.
Suppose a datum contains set, and the max number of elements is 2.
If we are changing from set that contains [A, B], to a set contains
[C, D], the diff datum will contains 4 elements [A, B, C, D].

Thus diff datum should not be constrained by the size limit. However
the datum after diff is applied should not violate the size limit.

Signed-off-by: Andy Zhou <az...@nicira.com>
---
 lib/ovsdb-data.c | 32 +++++++++++++++++++++++++++++---
 lib/ovsdb-data.h |  5 +++++
 2 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/lib/ovsdb-data.c b/lib/ovsdb-data.c
index a62e92e..592e9ed 100644
--- a/lib/ovsdb-data.c
+++ b/lib/ovsdb-data.c
@@ -1158,7 +1158,8 @@ static struct ovsdb_error *
 ovsdb_datum_from_json__(struct ovsdb_datum *datum,
                         const struct ovsdb_type *type,
                         const struct json *json,
-                        struct ovsdb_symbol_table *symtab)
+                        struct ovsdb_symbol_table *symtab,
+                        bool check_size)
 {
     struct ovsdb_error *error;
 
@@ -1179,7 +1180,7 @@ ovsdb_datum_from_json__(struct ovsdb_datum *datum,
         }
 
         n = inner->u.array.n;
-        if (n < type->n_min || n > type->n_max) {
+        if (check_size && (n < type->n_min || n > type->n_max)) {
             return ovsdb_syntax_error(json, NULL, "%s must have %u to "
                                       "%u members but %"PRIuSIZE" are present",
                                       class, type->n_min, type->n_max, n);
@@ -1256,7 +1257,32 @@ ovsdb_datum_from_json(struct ovsdb_datum *datum,
 {
     struct ovsdb_error *error;
 
-    error = ovsdb_datum_from_json__(datum, type, json, symtab);
+    error = ovsdb_datum_from_json__(datum, type, json, symtab, true);
+    if (error) {
+        return error;
+    }
+
+    error = ovsdb_datum_sort(datum, type->key.type);
+    if (error) {
+        ovsdb_datum_destroy(datum, type);
+    }
+    return error;
+}
+
+/* Parses 'json' as a datum of the type described by 'type' for internal
+ * use. This function is similar to 'ovsdb_datum_from_json', except:
+ * the member size of set or map is not checked.
+ *
+ * The datum generated should be used then discard. It is not suitable
+ * for storing into IDL because of the possible member size violation.  */
+struct ovsdb_error *
+ovsdb_transient_datum_from_json(struct ovsdb_datum *datum,
+                                const struct ovsdb_type *type,
+                                const struct json *json)
+{
+    struct ovsdb_error *error;
+
+    error =  ovsdb_datum_from_json__(datum, type, json, NULL, false);
     if (error) {
         return error;
     }
diff --git a/lib/ovsdb-data.h b/lib/ovsdb-data.h
index e144c70..802f718 100644
--- a/lib/ovsdb-data.h
+++ b/lib/ovsdb-data.h
@@ -161,6 +161,11 @@ struct ovsdb_error *ovsdb_datum_from_json(struct 
ovsdb_datum *,
                                           const struct json *,
                                           struct ovsdb_symbol_table *)
     OVS_WARN_UNUSED_RESULT;
+struct ovsdb_error *ovsdb_transient_datum_from_json(
+                                          struct ovsdb_datum *,
+                                          const struct ovsdb_type *,
+                                          const struct json *)
+    OVS_WARN_UNUSED_RESULT;
 struct json *ovsdb_datum_to_json(const struct ovsdb_datum *,
                                  const struct ovsdb_type *);
 
-- 
1.9.1

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