client: add mongoc_client_command() to API/ABI.

We should restructure the other wrappers to use this.

Author: Christian Hergert

mongoc/libmongoc.symbols

@@ -1,3 +1,4 @@
+mongoc_client_command
 mongoc_client_destroy
 mongoc_client_get_collection
 mongoc_client_get_database

mongoc/mongoc-client.c

@@ -34,6 +34,7 @@
 #include "mongoc-collection-private.h"
 #include "mongoc-config.h"
 #include "mongoc-counters-private.h"
+#include "mongoc-cursor-private.h"
 #include "mongoc-database-private.h"
 #include "mongoc-gridfs-private.h"
 #include "mongoc-error.h"
@@ -1076,3 +1077,31 @@ _mongoc_client_warm_up (mongoc_client_t *client,
 
    return ret;
 }
+
+
+mongoc_cursor_t *
+mongoc_client_command (mongoc_client_t           *client,
+                       const char                *db_name,
+                       mongoc_query_flags_t       flags,
+                       bson_uint32_t              skip,
+                       bson_uint32_t              n_return,
+                       const bson_t              *query,
+                       const bson_t              *fields,
+                       const mongoc_read_prefs_t *read_prefs)
+{
+   char ns[MONGOC_NAMESPACE_MAX];
+
+   BSON_ASSERT (client);
+   BSON_ASSERT (db_name);
+   BSON_ASSERT (query);
+
+   if (!read_prefs) {
+      read_prefs = client->read_prefs;
+   }
+
+   snprintf (ns, sizeof ns, "%s.$cmd", db_name);
+   ns[sizeof ns - 1] = '\0';
+
+   return _mongoc_cursor_new (client, ns, flags, skip, n_return, 100, TRUE,
+                              query, fields, read_prefs);
+}

mongoc/mongoc-client.h

@@ -23,6 +23,7 @@
 
 #include "mongoc-collection.h"
 #include "mongoc-config.h"
+#include "mongoc-cursor.h"
 #include "mongoc-database.h"
 #include "mongoc-gridfs.h"
 #include "mongoc-index.h"
@@ -84,6 +85,16 @@ mongoc_client_set_stream_initiator (mongoc_client_t           *client,
                                     mongoc_stream_initiator_t  initiator,
                                     void                      *user_data);
 
+mongoc_cursor_t *
+mongoc_client_command (mongoc_client_t           *client,
+                       const char                *db_name,
+                       mongoc_query_flags_t       flags,
+                       bson_uint32_t              skip,
+                       bson_uint32_t              n_return,
+                       const bson_t              *query,
+                       const bson_t              *fields,
+                       const mongoc_read_prefs_t *read_prefs);
+
 void
 mongoc_client_destroy (mongoc_client_t *client);
 

tests/test-mongoc-client.c

@@ -349,6 +349,35 @@ test_mongoc_client_read_prefs (void)
 }
 
 
+static void
+test_mongoc_client_command (void)
+{
+   mongoc_client_t *client;
+   mongoc_cursor_t *cursor;
+   const bson_t *doc;
+   bson_bool_t r;
+   bson_t cmd = BSON_INITIALIZER;
+
+   client = mongoc_client_new (gTestUri);
+   assert (client);
+
+   bson_append_int32 (&cmd, "ping", 4, 1);
+
+   cursor = mongoc_client_command (client, "admin", MONGOC_QUERY_NONE, 0, 1, &cmd, NULL, NULL);
+
+   r = mongoc_cursor_next (cursor, &doc);
+   assert (r);
+   assert (doc);
+
+   r = mongoc_cursor_next (cursor, &doc);
+   assert (!r);
+   assert (!doc);
+
+   mongoc_client_destroy (client);
+   bson_destroy (&cmd);
+}
+
+
 static void
 log_handler (mongoc_log_level_t  log_level,
              const char         *domain,
@@ -395,6 +424,7 @@ main (int   argc,
    run_test("/mongoc/client/authenticate", test_mongoc_client_authenticate);
    run_test("/mongoc/client/authenticate_failure", test_mongoc_client_authenticate_failure);
    run_test("/mongoc/client/read_prefs", test_mongoc_client_read_prefs);
+   run_test("/mongoc/client/command", test_mongoc_client_command);
 
    bson_free(gTestUri);
    bson_free(gTestUriWithPassword);