collection: add mongoc_collection_stats().

Author: Christian Hergert

build/cmake/libmongoc-ssl.def

@@ -40,6 +40,7 @@ mongoc_collection_rename
 mongoc_collection_save
 mongoc_collection_set_read_prefs
 mongoc_collection_set_write_concern
+mongoc_collection_stats
 mongoc_collection_update
 mongoc_collection_validate
 mongoc_cursor_clone

build/cmake/libmongoc.def

@@ -41,6 +41,7 @@ mongoc_collection_rename
 mongoc_collection_save
 mongoc_collection_set_read_prefs
 mongoc_collection_set_write_concern
+mongoc_collection_stats
 mongoc_collection_update
 mongoc_collection_validate
 mongoc_cursor_clone

src/libmongoc.symbols

@@ -42,6 +42,7 @@ mongoc_collection_rename
 mongoc_collection_save
 mongoc_collection_set_read_prefs
 mongoc_collection_set_write_concern
+mongoc_collection_stats
 mongoc_collection_update
 mongoc_collection_validate
 mongoc_cursor_clone

src/mongoc/mongoc-collection.c

@@ -1465,3 +1465,61 @@ mongoc_collection_rename (mongoc_collection_t *collection,
 
    return ret;
 }
+
+
+/*
+ *--------------------------------------------------------------------------
+ *
+ * mongoc_collection_stats --
+ *
+ *       Fetches statistics about the collection.
+ *
+ *       The result is stored in @stats, which should NOT be an initialized
+ *       bson_t or a leak will occur.
+ *
+ *       @stats, @options, and @error are optional.
+ *
+ * Returns:
+ *       true on success and @stats is set.
+ *       false on failure and @error is set.
+ *
+ * Side effects:
+ *       @stats and @error.
+ *
+ *--------------------------------------------------------------------------
+ */
+
+bool
+mongoc_collection_stats (mongoc_collection_t *collection,
+                         const bson_t        *options,
+                         bson_t              *stats,
+                         bson_error_t        *error)
+{
+   bson_iter_t iter;
+   bson_t cmd = BSON_INITIALIZER;
+   bool ret;
+
+   bson_return_val_if_fail (collection, false);
+
+   if (options &&
+       bson_iter_init_find (&iter, options, "scale") &&
+       !BSON_ITER_HOLDS_INT32 (&iter)) {
+      bson_set_error (error,
+                      MONGOC_ERROR_BSON,
+                      MONGOC_ERROR_BSON_INVALID,
+                      "'sacle' must be an int32 value.");
+      return false;
+   }
+
+   BSON_APPEND_UTF8 (&cmd, "collStats", collection->collection);
+
+   if (options) {
+      bson_concat (&cmd, options);
+   }
+
+   ret = mongoc_collection_command_simple (collection, &cmd, NULL, stats, error);
+
+   bson_destroy (&cmd);
+
+   return ret;
+}

src/mongoc/mongoc-collection.h

@@ -112,6 +112,10 @@ bool                          mongoc_collection_rename               (mongoc_col
                                                                       const char                    *new_name,
                                                                       bool                           drop_target_before_rename,
                                                                       bson_error_t                  *error);
+bool                          mongoc_collection_stats                (mongoc_collection_t           *collection,
+                                                                      const bson_t                  *options,
+                                                                      bson_t                        *reply,
+                                                                      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

@@ -707,6 +707,45 @@ test_rename (void)
 }
 
 
+static void
+test_stats (void)
+{
+   mongoc_collection_t *collection;
+   mongoc_client_t *client;
+   bson_error_t error;
+   bson_iter_t iter;
+   bson_t stats;
+   bson_t doc = BSON_INITIALIZER;
+   bool r;
+
+   client = mongoc_client_new (gTestUri);
+   ASSERT (client);
+
+   collection = get_test_collection (client, "test_stats");
+   ASSERT (collection);
+
+   r = mongoc_collection_insert (collection, MONGOC_INSERT_NONE, &doc, NULL, &error);
+   assert (r);
+
+   r = mongoc_collection_stats (collection, NULL, &stats, &error);
+   assert (r);
+
+   assert (bson_iter_init_find (&iter, &stats, "ns"));
+
+   assert (bson_iter_init_find (&iter, &stats, "count"));
+   assert (bson_iter_as_int64 (&iter) >= 1);
+
+   bson_destroy (&stats);
+
+   r = mongoc_collection_drop (collection, &error);
+   assert (r);
+
+   mongoc_collection_destroy (collection);
+   mongoc_client_destroy (client);
+   bson_destroy (&doc);
+}
+
+
 static void
 cleanup_globals (void)
 {
@@ -731,6 +770,7 @@ test_collection_install (TestSuite *suite)
    TestSuite_Add (suite, "/Collection/aggregate", test_aggregate);
    TestSuite_Add (suite, "/Collection/validate", test_validate);
    TestSuite_Add (suite, "/Collection/rename", test_rename);
+   TestSuite_Add (suite, "/Collection/stats", test_stats);
 
    atexit (cleanup_globals);
 }