Implement extension-less executable finding on Windows

Cargo.toml

@@ -21,6 +21,7 @@ rustix = { version = "0.38.10", default-features = false, features = ["fs", "std
 home = "0.5.5"
 
 [target.'cfg(windows)'.dependencies]
+windows-sys = { version = "0.48", features = ["Win32_Storage_FileSystem", "Win32_Foundation"] }
 once_cell = "1"
 
 [dev-dependencies]

src/checker.rs

@@ -40,6 +40,7 @@ impl Checker for ExistedChecker {
                 file_type.is_file() || file_type.is_symlink()
             })
             .unwrap_or(false)
+            && (path.extension().is_some() || matches_arch(&path))
     }
 
     #[cfg(not(target_os = "windows"))]
@@ -50,6 +51,18 @@ impl Checker for ExistedChecker {
     }
 }
 
+#[cfg(target_os = "windows")]
+fn matches_arch(path: &Path) -> bool {
+    use std::os::windows::prelude::OsStrExt;
+
+    let os_str = path.as_os_str().encode_wide().collect::<Vec<u16>>();
+    let mut out = 0;
+    let is_executable = unsafe {
+        windows_sys::Win32::Storage::FileSystem::GetBinaryTypeW(os_str.as_ptr(), &mut out)
+    };
+    is_executable != 0
+}
+
 pub struct CompositeChecker {
     checkers: Vec<Box<dyn Checker>>,
 }

src/error.rs

@@ -4,10 +4,11 @@ pub type Result<T> = std::result::Result<T, Error>;
 
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]
 pub enum Error {
-    BadAbsolutePath,
-    BadRelativePath,
+    /// An executable binary with that name was not found
     CannotFindBinaryPath,
-    CannotGetCurrentDir,
+    /// There was nowhere to search and the provided name wasn't an absolute path
+    CannotGetCurrentDirAndPathListEmpty,
+    /// Failed to canonicalize the path found
     CannotCanonicalize,
 }
 
@@ -16,10 +17,11 @@ impl std::error::Error for Error {}
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            Error::BadAbsolutePath => write!(f, "bad absolute path"),
-            Error::BadRelativePath => write!(f, "bad relative path"),
             Error::CannotFindBinaryPath => write!(f, "cannot find binary path"),
-            Error::CannotGetCurrentDir => write!(f, "cannot get current directory"),
+            Error::CannotGetCurrentDirAndPathListEmpty => write!(
+                f,
+                "no path to search and provided name is not an absolute path"
+            ),
             Error::CannotCanonicalize => write!(f, "cannot canonicalize path"),
         }
     }

src/finder.rs

@@ -198,7 +198,6 @@ impl Finder {
                 if has_executable_extension(&p, &PATH_EXTENSIONS) {
                     Box::new(iter::once(p))
                 } else {
-                    let bare_file = p.extension().map(|_| p.clone());
                     // Appended paths with windows executable extensions.
                     // e.g. path `c:/windows/bin[.ext]` will expand to:
                     // [c:/windows/bin.ext]
@@ -207,15 +206,13 @@ impl Finder {
                     // c:/windows/bin[.ext].CMD
                     // ...
                     Box::new(
-                        bare_file
-                            .into_iter()
-                            .chain(PATH_EXTENSIONS.iter().map(move |e| {
-                                // Append the extension.
-                                let mut p = p.clone().into_os_string();
-                                p.push(e);
+                        iter::once(p.clone()).chain(PATH_EXTENSIONS.iter().map(move |e| {
+                            // Append the extension.
+                            let mut p = p.clone().into_os_string();
+                            p.push(e);
 
-                                PathBuf::from(p)
-                            })),
+                            PathBuf::from(p)
+                        })),
                     )
                 }
             })

src/lib.rs

@@ -14,8 +14,6 @@
 //!
 //! ```
 
-#![forbid(unsafe_code)]
-
 mod checker;
 mod error;
 mod finder;