streamline rewriters - use structs for consistency

Author: SergioBenitez

core/lib/src/fs/mod.rs

@@ -11,4 +11,53 @@ pub use server::*;
 pub use named_file::*;
 pub use temp_file::*;
 pub use file_name::*;
-pub use server::relative;
+
+crate::export! {
+    /// Generates a crate-relative version of a path.
+    ///
+    /// This macro is primarily intended for use with [`FileServer`] to serve
+    /// files from a path relative to the crate root.
+    ///
+    /// The macro accepts one parameter, `$path`, an absolute or (preferably)
+    /// relative path. It returns a path as an `&'static str` prefixed with the
+    /// path to the crate root. Use `Path::new(relative!($path))` to retrieve an
+    /// `&'static Path`.
+    ///
+    /// # Example
+    ///
+    /// Serve files from the crate-relative `static/` directory:
+    ///
+    /// ```rust
+    /// # #[macro_use] extern crate rocket;
+    /// use rocket::fs::{FileServer, relative};
+    ///
+    /// #[launch]
+    /// fn rocket() -> _ {
+    ///     rocket::build().mount("/", FileServer::from(relative!("static")))
+    /// }
+    /// ```
+    ///
+    /// Path equivalences:
+    ///
+    /// ```rust
+    /// use std::path::Path;
+    ///
+    /// use rocket::fs::relative;
+    ///
+    /// let manual = Path::new(env!("CARGO_MANIFEST_DIR")).join("static");
+    /// let automatic_1 = Path::new(relative!("static"));
+    /// let automatic_2 = Path::new(relative!("/static"));
+    /// assert_eq!(manual, automatic_1);
+    /// assert_eq!(automatic_1, automatic_2);
+    /// ```
+    ///
+    macro_rules! relative {
+        ($path:expr) => {
+            if cfg!(windows) {
+                concat!(env!("CARGO_MANIFEST_DIR"), "\\", $path)
+            } else {
+                concat!(env!("CARGO_MANIFEST_DIR"), "/", $path)
+            }
+        };
+    }
+}