refactor!: replace ngx_null_string! with ngx_str_t::empty()

Author: bavshin-f5

examples/httporigdst.rs

@@ -8,25 +8,16 @@ use ngx::ffi::{
     sockaddr, sockaddr_storage, INET_ADDRSTRLEN, NGX_HTTP_MODULE,
 };
 use ngx::http::{self, HTTPModule};
-use ngx::{http_variable_get, ngx_log_debug_http, ngx_null_string, ngx_string};
+use ngx::{http_variable_get, ngx_log_debug_http, ngx_string};
 
 const IPV4_STRLEN: usize = INET_ADDRSTRLEN as usize;
 
-#[derive(Debug)]
+#[derive(Debug, Default)]
 struct NgxHttpOrigDstCtx {
     orig_dst_addr: ngx_str_t,
     orig_dst_port: ngx_str_t,
 }
 
-impl Default for NgxHttpOrigDstCtx {
-    fn default() -> NgxHttpOrigDstCtx {
-        NgxHttpOrigDstCtx {
-            orig_dst_addr: ngx_null_string!(),
-            orig_dst_port: ngx_null_string!(),
-        }
-    }
-}
-
 impl NgxHttpOrigDstCtx {
     pub fn save(&mut self, addr: &str, port: in_port_t, pool: &mut core::Pool) -> core::Status {
         let addr_data = pool.alloc_unaligned(addr.len());

nginx-sys/src/lib.rs

@@ -7,7 +7,7 @@ mod queue;
 
 use core::fmt;
 use core::mem::offset_of;
-use core::ptr::copy_nonoverlapping;
+use core::ptr::{self, copy_nonoverlapping};
 use core::slice;
 
 #[doc(hidden)]
@@ -130,6 +130,16 @@ impl ngx_str_t {
         core::str::from_utf8(self.as_bytes()).unwrap()
     }
 
+    /// Creates an empty `ngx_str_t` instance.
+    ///
+    /// This method replaces the `ngx_null_string` C macro.
+    pub const fn empty() -> Self {
+        ngx_str_t {
+            len: 0,
+            data: ptr::null_mut(),
+        }
+    }
+
     /// Create an `ngx_str_t` instance from a byte slice.
     ///
     /// # Safety
@@ -161,6 +171,12 @@ impl ngx_str_t {
     }
 }
 
+impl Default for ngx_str_t {
+    fn default() -> Self {
+        Self::empty()
+    }
+}
+
 impl From<ngx_str_t> for &[u8] {
     fn from(s: ngx_str_t) -> Self {
         if s.len == 0 || s.data.is_null() {
@@ -202,13 +218,13 @@ impl ngx_module_t {
         Self {
             ctx_index: ngx_uint_t::MAX,
             index: ngx_uint_t::MAX,
-            name: core::ptr::null_mut(),
+            name: ptr::null_mut(),
             spare0: 0,
             spare1: 0,
             version: nginx_version as ngx_uint_t,
             signature: NGX_RS_MODULE_SIGNATURE.as_ptr(),
-            ctx: core::ptr::null_mut(),
-            commands: core::ptr::null_mut(),
+            ctx: ptr::null_mut(),
+            commands: ptr::null_mut(),
             type_: 0,
             init_master: None,
             init_module: None,

src/core/mod.rs

@@ -17,7 +17,7 @@ pub use string::*;
 macro_rules! ngx_null_command {
     () => {
         $crate::ffi::ngx_command_t {
-            name: $crate::ngx_null_string!(),
+            name: $crate::ffi::ngx_str_t::empty(),
             type_: 0,
             set: None,
             conf: 0,

src/core/string.rs

@@ -6,7 +6,7 @@ use alloc::{borrow::Cow, string::String};
 #[cfg(feature = "std")]
 use std::{borrow::Cow, string::String};
 
-use crate::ffi::*;
+use crate::ffi::{ngx_str_t, u_char};
 
 /// Static string initializer for [`ngx_str_t`].
 ///
@@ -23,19 +23,6 @@ macro_rules! ngx_string {
     }};
 }
 
-/// Static empty string initializer for [`ngx_str_t`].
-///
-/// [`ngx_str_t`]: https://nginx.org/en/docs/dev/development_guide.html#string_overview
-#[macro_export]
-macro_rules! ngx_null_string {
-    () => {
-        $crate::ffi::ngx_str_t {
-            len: 0,
-            data: ::core::ptr::null_mut(),
-        }
-    };
-}
-
 /// Representation of a borrowed [Nginx string].
 ///
 /// [Nginx string]: https://nginx.org/en/docs/dev/development_guide.html#string_overview
@@ -100,7 +87,7 @@ impl AsRef<[u8]> for NgxStr {
 
 impl Default for &NgxStr {
     fn default() -> Self {
-        // SAFETY: The null `ngx_str_t` is always a valid Nginx string.
-        unsafe { NgxStr::from_ngx_str(ngx_null_string!()) }
+        // SAFETY: The empty `ngx_str_t` is always a valid Nginx string.
+        unsafe { NgxStr::from_ngx_str(ngx_str_t::default()) }
     }
 }

src/http/request.rs

@@ -6,7 +6,6 @@ use core::str::FromStr;
 use crate::core::*;
 use crate::ffi::*;
 use crate::http::status::*;
-use crate::ngx_null_string;
 
 /// Define a static request handler.
 ///
@@ -229,7 +228,7 @@ impl Request {
         // SAFETY: `ngx_http_complex_value` does not mutate `r` or `val` and guarentees that
         // a valid Nginx string is stored in `value` if it successfully returns.
         unsafe {
-            let mut value = ngx_null_string!();
+            let mut value = ngx_str_t::default();
             if ngx_http_complex_value(r, val, &mut value) != NGX_OK as ngx_int_t {
                 return None;
             }