Replace Either dependency with Result.

Cargo.toml

@@ -16,8 +16,6 @@ exclude = [
 [dependencies]
 # Private dependencies.
 libc = "0.2"
-# Public dependencies, exposed through library API.
-either = "1.5"
 
 [package.metadata.release]
 sign-commit = true

src/memfd.rs

@@ -172,11 +172,8 @@ impl Memfd {
     /// Otherwise the supplied `File` is returned for further usage.
     ///
     /// [`File`]: fs::File
-    pub fn try_from_file(file: fs::File) -> either::Either<Self, fs::File> {
-        match Self::try_from_fd(file) {
-            Ok(x) => either::Either::Left(x),
-            Err(e) => either::Either::Right(e),
-        }
+    pub fn try_from_file(file: fs::File) -> Result<Self, fs::File> {
+        Self::try_from_fd(file)
     }
 
     /// Return a reference to the backing [`File`].

tests/memfd.rs

@@ -42,13 +42,11 @@ fn test_memfd_from_into() {
     let m0 = opts.create("default").unwrap();
     let f0 = m0.into_file();
     let _ = memfd::Memfd::try_from_file(f0)
-        .left()
         .expect("failed to convert a legit memfd file");
 
     let rootdir = fs::File::open("/").unwrap();
     let _ = memfd::Memfd::try_from_file(rootdir)
-        .right()
-        .expect("unexpected conversion from a non-memfd file");
+        .expect_err("unexpected conversion from a non-memfd file");
 }
 
 /// Check if the close-on-exec flag is set for the memfd.