Extend user path param with --current-user

Recently support of `--user-id|--user-name` has been added when user_id
is a path parameter of the resource. To make it even more smoother
extend it with `--user-id <ID>|--user-name <NAME>|--current-user` to
allow using current authenticated user while being very explicit (ensure
user precisely decides what is desired.

Change-Id: I0261140572e76799ea54dc0c9544cf5d094c1120

codegenerator/rust_cli.py

@@ -1037,6 +1037,7 @@ class RustCliGenerator(BaseGenerator):
                     global_additional_imports.add(
                         f"openstack_sdk::api::{'::'.join(link_res_name.split('/'))}::find as find_{link_res_name.split('/')[-1]}"
                     )
+                    global_additional_imports.add("eyre::OptionExt")
 
         # List of operation variants (based on the body)
         operation_variants = common.get_operation_variants(spec, args.operation_name)

codegenerator/templates/rust_cli/path_parameters.j2

@@ -31,6 +31,11 @@ struct {{ res_name | title }}Input {
       /// {{ res_name | title }} ID.
     #[arg(long, help_heading = "Path parameters", value_name = "{{ res_name | upper }}_ID")]
     {{ res_name }}_id: Option<String>,
+    {%- if res_name == "user" %}
+    /// Current authenticated user.
+    #[arg(long, help_heading = "Path parameters", action = clap::ArgAction::SetTrue)]
+    current_user: bool,
+    {%- endif %}
 }
   {%- endif %}
 {%- endfor %}

codegenerator/templates/rust_macros.j2

@@ -418,6 +418,18 @@ Some({{ val }})
                 }
             };
         }
+        {%- if res_name == "user" and v.remote_name == "user_id" %}
+        else if self.path.{{ res_name }}.current_{{ res_name }} {
+            {{ builder }}.{{ v.remote_name }}(
+                client
+                    .get_auth_info()
+                    .ok_or_eyre("Cannot determine current authentication information")?
+                    .token
+                    .user
+                    .id,
+            );
+        }
+        {%- endif %}
   {%- else %}
   {%- if not v.is_required %}
     {%- if k != "project_id" %}