collection: add mongoc_collection_rename().

Author: Christian Hergert

build/cmake/libmongoc-ssl.def

@@ -36,6 +36,7 @@ mongoc_collection_get_write_concern
 mongoc_collection_insert
 mongoc_collection_insert_bulk
 mongoc_collection_keys_to_index_string
+mongoc_collection_rename
 mongoc_collection_save
 mongoc_collection_set_read_prefs
 mongoc_collection_set_write_concern

build/cmake/libmongoc.def

@@ -37,6 +37,7 @@ mongoc_collection_get_write_concern
 mongoc_collection_insert
 mongoc_collection_insert_bulk
 mongoc_collection_keys_to_index_string
+mongoc_collection_rename
 mongoc_collection_save
 mongoc_collection_set_read_prefs
 mongoc_collection_set_write_concern

src/libmongoc.symbols

@@ -38,6 +38,7 @@ mongoc_collection_get_write_concern
 mongoc_collection_insert
 mongoc_collection_insert_bulk
 mongoc_collection_keys_to_index_string
+mongoc_collection_rename
 mongoc_collection_save
 mongoc_collection_set_read_prefs
 mongoc_collection_set_write_concern

src/mongoc/mongoc-collection.c

@@ -35,6 +35,20 @@
 #define MONGOC_LOG_DOMAIN "collection"
 
 
+static bool
+validate_name (const char *str)
+{
+   return (str &&
+           *str &&
+           (strlen (str) < 123) &&
+           !strstr (str, "..") &&
+           !!strncmp (str, "$cmd", 4) &&
+           !!strncmp (str, "oplog.$main", 11) &&
+           (*str != '.') &&
+           (*(str + strlen (str) - 1) != '.'));
+}
+
+
 /*
  *--------------------------------------------------------------------------
  *
@@ -84,11 +98,9 @@ _mongoc_collection_new (mongoc_client_t              *client,
       mongoc_read_prefs_copy(read_prefs) :
       mongoc_read_prefs_new(MONGOC_READ_PRIMARY);
 
-   bson_snprintf (col->ns, sizeof col->ns - 1, "%s.%s",
-                  db, collection);
-   bson_snprintf (col->db, sizeof col->db - 1, "%s", db);
-   bson_snprintf (col->collection, sizeof col->collection - 1,
-                  "%s", collection);
+   bson_snprintf (col->ns, sizeof col->ns, "%s.%s", db, collection);
+   bson_snprintf (col->db, sizeof col->db, "%s", db);
+   bson_snprintf (col->collection, sizeof col->collection, "%s", collection);
 
    col->collectionlen = (uint32_t)strlen(col->collection);
    col->nslen = (uint32_t)strlen(col->ns);
@@ -1374,3 +1386,82 @@ mongoc_collection_validate (mongoc_collection_t *collection, /* IN */
 
    return ret;
 }
+
+
+/*
+ *--------------------------------------------------------------------------
+ *
+ * mongoc_collection_rename --
+ *
+ *       Rename the collection to @new_name.
+ *
+ *       If @new_db is NULL, the same db will be used.
+ *
+ *       If @drop_target_before_rename is true, then a collection named
+ *       @new_name will be dropped before renaming @collection to
+ *       @new_name.
+ *
+ * Returns:
+ *       true on success; false on failure and @error is set.
+ *
+ * Side effects:
+ *       @error is set on failure.
+ *
+ *--------------------------------------------------------------------------
+ */
+
+bool
+mongoc_collection_rename (mongoc_collection_t *collection,
+                          const char          *new_db,
+                          const char          *new_name,
+                          bool                 drop_target_before_rename,
+                          bson_error_t        *error)
+{
+   bson_t cmd = BSON_INITIALIZER;
+   char newns [MONGOC_NAMESPACE_MAX + 1];
+   bool ret;
+
+   bson_return_val_if_fail (collection, false);
+   bson_return_val_if_fail (new_name, false);
+
+   if (!validate_name (new_name)) {
+      bson_set_error (error,
+                      MONGOC_ERROR_NAMESPACE,
+                      MONGOC_ERROR_NAMESPACE_INVALID,
+                      "\"%s\" is an invalid collection name.",
+                      new_name);
+      return false;
+   }
+
+   bson_snprintf (newns, sizeof newns, "%s.%s",
+                  new_db ? new_db : collection->db,
+                  new_name);
+
+   BSON_APPEND_UTF8 (&cmd, "renameCollection", collection->ns);
+   BSON_APPEND_UTF8 (&cmd, "to", newns);
+
+   if (drop_target_before_rename) {
+      BSON_APPEND_BOOL (&cmd, "dropTarget", true);
+   }
+
+   ret = mongoc_client_command_simple (collection->client, "admin",
+                                       &cmd, NULL, NULL, error);
+
+   if (ret) {
+      if (new_db) {
+         bson_snprintf (collection->db, sizeof collection->db, "%s", new_db);
+      }
+
+      bson_snprintf (collection->collection, sizeof collection->collection,
+                     "%s", new_name);
+      collection->collectionlen = strlen (collection->collection);
+
+      bson_snprintf (collection->ns, sizeof collection->ns,
+                     "%s.%s", collection->db, new_name);
+      collection->nslen = strlen (collection->ns);
+   }
+
+   bson_destroy (&cmd);
+
+   return ret;
+}

src/mongoc/mongoc-collection.h

@@ -107,6 +107,11 @@ bool                          mongoc_collection_save                 (mongoc_col
                                                                       const bson_t                  *document,
                                                                       const mongoc_write_concern_t  *write_concern,
                                                                       bson_error_t                  *error);
+bool                          mongoc_collection_rename               (mongoc_collection_t           *collection,
+                                                                      const char                    *new_db,
+                                                                      const char                    *new_name,
+                                                                      bool                           drop_target_before_rename,
+                                                                      bson_error_t                  *error);
 const mongoc_read_prefs_t    *mongoc_collection_get_read_prefs       (const mongoc_collection_t     *collection);
 void                          mongoc_collection_set_read_prefs       (mongoc_collection_t           *collection,
                                                                       const mongoc_read_prefs_t     *read_prefs);

tests/test-mongoc-collection.c

@@ -677,6 +677,36 @@ test_validate (void)
 }
 
 
+static void
+test_rename (void)
+{
+   mongoc_collection_t *collection;
+   mongoc_client_t *client;
+   bson_error_t error;
+   bson_t doc = BSON_INITIALIZER;
+   bool r;
+
+   client = mongoc_client_new (gTestUri);
+   ASSERT (client);
+
+   collection = get_test_collection (client, "test_rename");
+   ASSERT (collection);
+
+   r = mongoc_collection_insert (collection, MONGOC_INSERT_NONE, &doc, NULL, &error);
+   assert (r);
+
+   r = mongoc_collection_rename (collection, "test", "test_rename_2", false, &error);
+   assert (r);
+
+   r = mongoc_collection_drop (collection, &error);
+   assert (r);
+
+   mongoc_collection_destroy (collection);
+   mongoc_client_destroy (client);
+   bson_destroy (&doc);
+}
+
+
 static void
 cleanup_globals (void)
 {
@@ -700,6 +730,7 @@ test_collection_install (TestSuite *suite)
    TestSuite_Add (suite, "/Collection/drop", test_drop);
    TestSuite_Add (suite, "/Collection/aggregate", test_aggregate);
    TestSuite_Add (suite, "/Collection/validate", test_validate);
+   TestSuite_Add (suite, "/Collection/rename", test_rename);
 
    atexit (cleanup_globals);
 }