CDRIVER-4389 Update FLE 2 Create Collection (#993)

* create state collections with clusteredIndex

* drop data collection after state collections

Author: kevinAlbs

src/libmongoc/src/mongoc/mongoc-collection.c

@@ -1065,15 +1065,6 @@ drop_with_opts_with_encryptedFields (mongoc_collection_t *collection,
    bool ok = false;
    const char *name = mongoc_collection_get_name (collection);
 
-   /* Drop data collection. */
-   if (!drop_with_opts (collection, opts, error)) {
-      if (error->code == MONGOC_SERVER_ERR_NS_NOT_FOUND) {
-         memset (error, 0, sizeof (bson_error_t));
-      } else {
-         goto fail;
-      }
-   }
-
    /* Drop ESC collection. */
    escName = _mongoc_get_encryptedField_state_collection (
       encryptedFields, name, "esc", error);
@@ -1125,6 +1116,15 @@ drop_with_opts_with_encryptedFields (mongoc_collection_t *collection,
       }
    }
 
+   /* Drop data collection. */
+   if (!drop_with_opts (collection, opts, error)) {
+      if (error->code == MONGOC_SERVER_ERR_NS_NOT_FOUND) {
+         memset (error, 0, sizeof (bson_error_t));
+      } else {
+         goto fail;
+      }
+   }
+
    ok = true;
 fail:
    mongoc_collection_destroy (ecocCollection);

src/libmongoc/src/mongoc/mongoc-database.c

@@ -1046,15 +1046,27 @@ create_encField_state_collection (mongoc_database_t *database,
    char *state_collection = NULL;
    mongoc_collection_t *collection = NULL;
    bool ok = false;
+   bson_t opts = BSON_INITIALIZER;
 
    state_collection = _mongoc_get_encryptedField_state_collection (
       encryptedFields, data_collection, state_collection_suffix, error);
    if (!state_collection) {
       goto fail;
    }
 
-   collection =
-      create_collection (database, state_collection, NULL /* opts */, error);
+   BCON_APPEND (&opts,
+                "clusteredIndex",
+                "{",
+                "key",
+                "{",
+                "_id",
+                BCON_INT32 (1),
+                "}",
+                "unique",
+                BCON_BOOL (true),
+                "}");
+
+   collection = create_collection (database, state_collection, &opts, error);
    if (collection == NULL) {
       goto fail;
    }
@@ -1063,6 +1075,7 @@ create_encField_state_collection (mongoc_database_t *database,
 fail:
    bson_free (state_collection);
    mongoc_collection_destroy (collection);
+   bson_destroy (&opts);
    return ok;
 }