refactor!: remove macros for initializing empty ngx_*_variable_t

There are no nginx core APIs that take a list of variables, terminated
by an empty entry. The variables are always added from the module code,
where we should use Rust iterators.

Author: bavshin-f5

examples/httporigdst.rs

@@ -8,7 +8,7 @@ use ngx::ffi::{
     sockaddr, sockaddr_storage, INET_ADDRSTRLEN, NGX_HTTP_MODULE,
 };
 use ngx::http::{self, HTTPModule};
-use ngx::{http_variable_get, ngx_http_null_variable, ngx_log_debug_http, ngx_null_string, ngx_string};
+use ngx::{http_variable_get, ngx_log_debug_http, ngx_null_string, ngx_string};
 
 const IPV4_STRLEN: usize = INET_ADDRSTRLEN as usize;
 
@@ -102,7 +102,7 @@ pub static mut ngx_http_orig_dst_module: ngx_module_t = ngx_module_t {
     ..ngx_module_t::default()
 };
 
-static mut NGX_HTTP_ORIG_DST_VARS: [ngx_http_variable_t; 3] = [
+static mut NGX_HTTP_ORIG_DST_VARS: [ngx_http_variable_t; 2] = [
     // ngx_str_t name
     // ngx_http_set_variable_pt set_handler
     // ngx_http_get_variable_pt get_handler
@@ -125,7 +125,6 @@ static mut NGX_HTTP_ORIG_DST_VARS: [ngx_http_variable_t; 3] = [
         flags: 0,
         index: 0,
     },
-    ngx_http_null_variable!(),
 ];
 
 unsafe fn ngx_get_origdst(request: &mut http::Request) -> Result<(String, in_port_t), core::Status> {
@@ -276,9 +275,6 @@ impl HTTPModule for Module {
     // static ngx_int_t ngx_http_orig_dst_add_variables(ngx_conf_t *cf)
     unsafe extern "C" fn preconfiguration(cf: *mut ngx_conf_t) -> ngx_int_t {
         for mut v in NGX_HTTP_ORIG_DST_VARS {
-            if v.name.len == 0 {
-                break;
-            }
             let var = ngx_http_add_variable(cf, &mut v.name, v.flags);
             if var.is_null() {
                 return core::Status::NGX_ERROR.into();

src/core/mod.rs

@@ -26,41 +26,3 @@ macro_rules! ngx_null_command {
         }
     };
 }
-
-/// Static empty configuration variable initializer for [`ngx_http_variable_t`].
-///
-/// This is typically used to terminate an array of HTTP variable types.
-///
-/// [`ngx_http_variable_t`]: https://nginx.org/en/docs/dev/development_guide.html#http_variables
-#[macro_export]
-macro_rules! ngx_http_null_variable {
-    () => {
-        $crate::ffi::ngx_http_variable_t {
-            name: $crate::ngx_null_string!(),
-            set_handler: None,
-            get_handler: None,
-            data: 0,
-            flags: 0,
-            index: 0,
-        }
-    };
-}
-
-/// Static empty configuration variable initializer for [`ngx_stream_variable_t`].
-///
-/// This is typically used to terminate an array of Stream variable types.
-///
-/// [`ngx_stream_variable_t`]: https://github.com/nginx/nginx/blob/1a8ef991d92d22eb8aded7f49595dd31a639e8a4/src/stream/ngx_stream_variables.h#L21
-#[macro_export]
-macro_rules! ngx_stream_null_variable {
-    () => {
-        $crate::ffi::ngx_stream_variable_t {
-            name: $crate::ngx_null_string!(),
-            set_handler: None,
-            get_handler: None,
-            data: 0,
-            flags: 0,
-            index: 0,
-        }
-    };
-}