CDRIVER-1195: Implement mongoc_server_description_round_trip_time() (#321)

Author: jmikola

build/autotools/versions.ldscript

@@ -341,6 +341,7 @@ LIBMONGOC_1.4 {
         mongoc_log_trace_disable;
         mongoc_log_trace_enable;
         mongoc_server_description_ismaster;
+        mongoc_server_description_round_trip_time;
         mongoc_server_description_type;
         mongoc_server_descriptions_destroy_all;
         mongoc_uri_get_option_as_bool;

build/cmake/libmongoc-ssl.def

@@ -247,6 +247,7 @@ mongoc_server_description_host
 mongoc_server_description_id
 mongoc_server_description_ismaster
 mongoc_server_description_new_copy
+mongoc_server_description_round_trip_time
 mongoc_server_description_type
 mongoc_server_descriptions_destroy_all
 mongoc_socket_accept

build/cmake/libmongoc.def

@@ -242,6 +242,7 @@ mongoc_server_description_host
 mongoc_server_description_id
 mongoc_server_description_ismaster
 mongoc_server_description_new_copy
+mongoc_server_description_round_trip_time
 mongoc_server_description_type
 mongoc_server_descriptions_destroy_all
 mongoc_socket_accept

doc/mongoc_server_description_round_trip_time.page

@@ -0,0 +1,32 @@
+<?xml version="1.0"?>
+<page xmlns="http://projectmallard.org/1.0/"
+      type="topic"
+      style="function"
+      xmlns:api="http://projectmallard.org/experimental/api/"
+      xmlns:ui="http://projectmallard.org/experimental/ui/"
+      id="mongoc_server_description_round_trip_time">
+  <info>
+    <link type="guide" xref="mongoc_server_description_t" group="function"/>
+  </info>
+  <title>mongoc_server_description_round_trip_time()</title>
+
+  <section id="synopsis">
+    <title>Synopsis</title>
+    <synopsis><code mime="text/x-csrc"><![CDATA[int64_t
+mongoc_server_description_round_trip_time (const mongoc_server_description_t *description);
+]]></code></synopsis>
+  </section>
+
+  <section id="parameters">
+    <title>Parameters</title>
+    <table>
+      <tr><td><p>description</p></td><td><p>A <code xref="mongoc_server_description_t">mongoc_server_description_t</code>.</p></td></tr>
+    </table>
+  </section>
+
+  <section id="description">
+    <title>Description</title>
+    <p>Get the server's round trip time in milliseconds. This is the client's measurement of the duration of an "ismaster" command.</p>
+  </section>
+
+</page>

src/mongoc/mongoc-server-description.c

@@ -270,6 +270,26 @@ mongoc_server_description_host (mongoc_server_description_t *description)
    return &description->host;
 }
 
+/*
+ *--------------------------------------------------------------------------
+ *
+ * mongoc_server_description_round_trip_time --
+ *
+ *      Get the round trip time of this server, which is the client's
+ *      measurement of the duration of an "ismaster" command.
+ *
+ * Returns:
+ *      The server's round trip time in milliseconds.
+ *
+ *--------------------------------------------------------------------------
+ */
+
+int64_t
+mongoc_server_description_round_trip_time (mongoc_server_description_t *description)
+{
+   return description->round_trip_time;
+}
+
 /*
  *--------------------------------------------------------------------------
  *

src/mongoc/mongoc-server-description.h

@@ -36,6 +36,9 @@ mongoc_server_description_id (mongoc_server_description_t *description);
 mongoc_host_list_t *
 mongoc_server_description_host (mongoc_server_description_t *description);
 
+int64_t
+mongoc_server_description_round_trip_time (mongoc_server_description_t *description);
+
 const char *
 mongoc_server_description_type (mongoc_server_description_t *description);