back to supertrait sealing

Author: nagisa

src/as_filename.rs

@@ -1,36 +1,34 @@
-#![allow(private_interfaces)]
 use crate::Error;
 use alloc::string::String;
 
-pub(crate) struct SealedFilename;
-
-/// This trait is implemented for types that can be used as a filename when loading new
-/// [`Library`](crate::Library) instances.
-///
-/// It is currently sealed and cannot be implemented or its methods called by users of this crate.
-pub trait AsFilename {
+pub(crate) trait Sealed {
     #[cfg(windows)]
     #[doc(hidden)]
     fn windows_filename<R>(
         self,
-        sealed: SealedFilename,
         function: impl FnOnce(*const u16) -> Result<R, crate::Error>,
     ) -> Result<R, crate::Error>;
 
     #[cfg(unix)]
     #[doc(hidden)]
     fn posix_filename<R>(
         self,
-        sealed: SealedFilename,
         function: impl FnOnce(*const core::ffi::c_char) -> Result<R, crate::Error>,
     ) -> Result<R, crate::Error>;
 }
 
-impl AsFilename for &str {
+/// This trait is implemented for types that can be used as a filename when loading new
+/// [`Library`](crate::Library) instances.
+///
+/// It is currently sealed and cannot be implemented or its methods called by users of this crate.
+#[allow(private_bounds)]
+pub trait AsFilename: Sealed {}
+
+impl AsFilename for &str {}
+impl Sealed for &str {
     #[cfg(windows)]
     fn windows_filename<R>(
         self,
-        _seal: SealedFilename,
         function: impl FnOnce(*const u16) -> Result<R, Error>,
     ) -> Result<R, Error> {
         let utf16: alloc::vec::Vec<u16> = if crate::util::check_null_bytes(self.as_bytes())? {
@@ -44,7 +42,6 @@ impl AsFilename for &str {
     #[cfg(unix)]
     fn posix_filename<R>(
         self,
-        _seal: SealedFilename,
         function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
     ) -> Result<R, Error> {
         if crate::util::check_null_bytes(self.as_bytes())? {
@@ -56,40 +53,38 @@ impl AsFilename for &str {
     }
 }
 
-impl AsFilename for &String {
+impl AsFilename for &String {}
+impl Sealed for &String {
     #[cfg(windows)]
     fn windows_filename<R>(
         self,
-        seal: SealedFilename,
         function: impl FnOnce(*const u16) -> Result<R, Error>,
     ) -> Result<R, Error> {
-        self.as_str().windows_filename(seal, function)
+        self.as_str().windows_filename(function)
     }
 
     #[cfg(unix)]
     fn posix_filename<R>(
         self,
-        seal: SealedFilename,
         function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
     ) -> Result<R, Error> {
-        self.as_str().posix_filename(seal, function)
+        self.as_str().posix_filename(function)
     }
 }
 
-impl AsFilename for String {
+impl AsFilename for String {}
+impl Sealed for String {
     #[cfg(windows)]
     fn windows_filename<R>(
         self,
-        seal: SealedFilename,
         function: impl FnOnce(*const u16) -> Result<R, Error>,
     ) -> Result<R, Error> {
-        self.as_str().windows_filename(seal, function)
+        self.as_str().windows_filename(function)
     }
 
     #[cfg(unix)]
     fn posix_filename<R>(
         mut self,
-        _seal: SealedFilename,
         function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
     ) -> Result<R, Error> {
         if crate::util::check_null_bytes(self.as_bytes())? {
@@ -104,15 +99,15 @@ impl AsFilename for String {
 #[cfg(feature = "std")]
 #[cfg_attr(libloading_docs, doc(cfg(feature = "std")))]
 mod std {
-    use super::{AsFilename, SealedFilename};
+    use super::{Sealed, AsFilename};
     use crate::Error;
     use std::ffi::{OsStr, OsString};
 
-    impl AsFilename for &OsStr {
+    impl AsFilename for &OsStr {}
+    impl Sealed for &OsStr {
         #[cfg(windows)]
         fn windows_filename<R>(
             self,
-            _seal: SealedFilename,
             function: impl FnOnce(*const u16) -> Result<R, Error>,
         ) -> Result<R, Error> {
             use std::os::windows::ffi::OsStrExt;
@@ -128,7 +123,6 @@ mod std {
         #[cfg(unix)]
         fn posix_filename<R>(
             self,
-            _seal: SealedFilename,
             function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
         ) -> Result<R, Error> {
             let bytes = std::os::unix::ffi::OsStrExt::as_bytes(self);
@@ -141,44 +135,42 @@ mod std {
         }
     }
 
-    impl AsFilename for &OsString {
+    impl AsFilename for &OsString {}
+    impl Sealed for &OsString {
         #[cfg(windows)]
         fn windows_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const u16) -> Result<R, Error>,
         ) -> Result<R, Error> {
-            self.as_os_str().windows_filename(seal, function)
+            self.as_os_str().windows_filename(function)
         }
 
         #[cfg(unix)]
         fn posix_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
         ) -> Result<R, Error> {
-            self.as_os_str().posix_filename(seal, function)
+            self.as_os_str().posix_filename(function)
         }
     }
 
-    impl AsFilename for OsString {
+    impl AsFilename for OsString {}
+    impl Sealed for OsString {
         #[cfg(windows)]
         fn windows_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const u16) -> Result<R, Error>,
         ) -> Result<R, Error> {
             // This is the best we can do.
             // There is no into_wide for windows.
             // The internal repr is wtf-8 and this is different
             // from LCPWSTR that we need for the ffi calls.
-            self.as_os_str().windows_filename(seal, function)
+            self.as_os_str().windows_filename(function)
         }
 
         #[cfg(unix)]
         fn posix_filename<R>(
             self,
-            _seal: SealedFilename,
             function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
         ) -> Result<R, Error> {
             let mut bytes = std::os::unix::ffi::OsStringExt::into_vec(self);
@@ -191,63 +183,60 @@ mod std {
         }
     }
 
-    impl AsFilename for std::path::PathBuf {
+    impl AsFilename for std::path::PathBuf {}
+    impl Sealed for std::path::PathBuf {
         #[cfg(windows)]
         fn windows_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const u16) -> Result<R, Error>,
         ) -> Result<R, Error> {
-            self.into_os_string().windows_filename(seal, function)
+            self.into_os_string().windows_filename(function)
         }
 
         #[cfg(unix)]
         fn posix_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
         ) -> Result<R, Error> {
-            self.into_os_string().posix_filename(seal, function)
+            self.into_os_string().posix_filename(function)
         }
     }
 
-    impl AsFilename for &std::path::PathBuf {
+    impl AsFilename for &std::path::PathBuf {}
+    impl Sealed for &std::path::PathBuf {
         #[cfg(windows)]
         fn windows_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const u16) -> Result<R, Error>,
         ) -> Result<R, Error> {
-            self.as_os_str().windows_filename(seal, function)
+            self.as_os_str().windows_filename(function)
         }
 
         #[cfg(unix)]
         fn posix_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
         ) -> Result<R, Error> {
-            self.as_os_str().posix_filename(seal, function)
+            self.as_os_str().posix_filename(function)
         }
     }
 
-    impl AsFilename for &std::path::Path {
+    impl AsFilename for &std::path::Path {}
+    impl Sealed for &std::path::Path {
         #[cfg(windows)]
         fn windows_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const u16) -> Result<R, Error>,
         ) -> Result<R, Error> {
-            self.as_os_str().windows_filename(seal, function)
+            self.as_os_str().windows_filename(function)
         }
 
         #[cfg(unix)]
         fn posix_filename<R>(
             self,
-            seal: SealedFilename,
             function: impl FnOnce(*const core::ffi::c_char) -> Result<R, Error>,
         ) -> Result<R, Error> {
-            self.as_os_str().posix_filename(seal, function)
+            self.as_os_str().posix_filename(function)
         }
     }
 }