refactor(tvix/eval): use &Path instead of PathBuf

This allows getting rid of some clones in eval/src/vm/generators.rs.

Change-Id: I330390307d3bcfeef19c98954c753ee55b1ccee3
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8604
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

tvix/cli/src/nix_compat.rs

@@ -47,7 +47,7 @@ impl EvalIO for NixCompatIO {
     }
 
     // Pass the rest of the functions through to `Self::underlying`
-    fn path_exists(&mut self, path: PathBuf) -> Result<bool, io::Error> {
+    fn path_exists(&mut self, path: &Path) -> Result<bool, io::Error> {
         if path.starts_with("/__corepkgs__") {
             return Ok(true);
         }
@@ -55,7 +55,7 @@ impl EvalIO for NixCompatIO {
         self.underlying.path_exists(path)
     }
 
-    fn read_to_string(&mut self, path: PathBuf) -> Result<String, io::Error> {
+    fn read_to_string(&mut self, path: &Path) -> Result<String, io::Error> {
         // Bundled version of corepkgs/fetchurl.nix. This workaround
         // is similar to what cppnix does for passing the path
         // through.
@@ -69,7 +69,7 @@ impl EvalIO for NixCompatIO {
         self.underlying.read_to_string(path)
     }
 
-    fn read_dir(&mut self, path: PathBuf) -> Result<Vec<(SmolStr, FileType)>, io::Error> {
+    fn read_dir(&mut self, path: &Path) -> Result<Vec<(SmolStr, FileType)>, io::Error> {
         self.underlying.read_dir(path)
     }
 }

tvix/cli/src/tvix_io.rs

@@ -48,7 +48,7 @@ impl<T: EvalIO> EvalIO for TvixIO<T> {
         Ok(imported_path)
     }
 
-    fn path_exists(&mut self, path: PathBuf) -> Result<bool, io::Error> {
+    fn path_exists(&mut self, path: &Path) -> Result<bool, io::Error> {
         if path.starts_with("/__corepkgs__") {
             return Ok(true);
         }
@@ -56,7 +56,7 @@ impl<T: EvalIO> EvalIO for TvixIO<T> {
         self.actual.path_exists(path)
     }
 
-    fn read_to_string(&mut self, path: PathBuf) -> Result<String, io::Error> {
+    fn read_to_string(&mut self, path: &Path) -> Result<String, io::Error> {
         // Bundled version of corepkgs/fetchurl.nix. The counterpart
         // of this happens in `main`, where the `nix_path` of the
         // evaluation has `nix=/__corepkgs__` added to it.
@@ -73,7 +73,7 @@ impl<T: EvalIO> EvalIO for TvixIO<T> {
         self.actual.read_to_string(path)
     }
 
-    fn read_dir(&mut self, path: PathBuf) -> Result<Vec<(SmolStr, FileType)>, io::Error> {
+    fn read_dir(&mut self, path: &Path) -> Result<Vec<(SmolStr, FileType)>, io::Error> {
         self.actual.read_dir(path)
     }
 }

tvix/eval/src/io.rs

@@ -33,14 +33,14 @@ pub enum FileType {
 /// Defines how filesystem interaction occurs inside of tvix-eval.
 pub trait EvalIO {
     /// Verify whether the file at the specified path exists.
-    fn path_exists(&mut self, path: PathBuf) -> Result<bool, io::Error>;
+    fn path_exists(&mut self, path: &Path) -> Result<bool, io::Error>;
 
     /// Read the file at the specified path to a string.
-    fn read_to_string(&mut self, path: PathBuf) -> Result<String, io::Error>;
+    fn read_to_string(&mut self, path: &Path) -> Result<String, io::Error>;
 
     /// Read the directory at the specified path and return the names
     /// of its entries associated with their [`FileType`].
-    fn read_dir(&mut self, path: PathBuf) -> Result<Vec<(SmolStr, FileType)>, io::Error>;
+    fn read_dir(&mut self, path: &Path) -> Result<Vec<(SmolStr, FileType)>, io::Error>;
 
     /// Import the given path. What this means depends on the
     /// implementation, for example for a `std::io`-based
@@ -65,15 +65,15 @@ pub struct StdIO;
 
 #[cfg(feature = "impure")]
 impl EvalIO for StdIO {
-    fn path_exists(&mut self, path: PathBuf) -> Result<bool, io::Error> {
+    fn path_exists(&mut self, path: &Path) -> Result<bool, io::Error> {
         path.try_exists()
     }
 
-    fn read_to_string(&mut self, path: PathBuf) -> Result<String, io::Error> {
+    fn read_to_string(&mut self, path: &Path) -> Result<String, io::Error> {
         std::fs::read_to_string(&path)
     }
 
-    fn read_dir(&mut self, path: PathBuf) -> Result<Vec<(SmolStr, FileType)>, io::Error> {
+    fn read_dir(&mut self, path: &Path) -> Result<Vec<(SmolStr, FileType)>, io::Error> {
         let mut result = vec![];
 
         for entry in path.read_dir()? {
@@ -108,21 +108,21 @@ impl EvalIO for StdIO {
 pub struct DummyIO;
 
 impl EvalIO for DummyIO {
-    fn path_exists(&mut self, _: PathBuf) -> Result<bool, io::Error> {
+    fn path_exists(&mut self, _: &Path) -> Result<bool, io::Error> {
         Err(io::Error::new(
             io::ErrorKind::Unsupported,
             "I/O methods are not implemented in DummyIO",
         ))
     }
 
-    fn read_to_string(&mut self, _: PathBuf) -> Result<String, io::Error> {
+    fn read_to_string(&mut self, _: &Path) -> Result<String, io::Error> {
         Err(io::Error::new(
             io::ErrorKind::Unsupported,
             "I/O methods are not implemented in DummyIO",
         ))
     }
 
-    fn read_dir(&mut self, _: PathBuf) -> Result<Vec<(SmolStr, FileType)>, io::Error> {
+    fn read_dir(&mut self, _: &Path) -> Result<Vec<(SmolStr, FileType)>, io::Error> {
         Err(io::Error::new(
             io::ErrorKind::Unsupported,
             "I/O methods are not implemented in DummyIO",

tvix/eval/src/nix_search_path.rs

@@ -85,7 +85,7 @@ impl NixSearchPathEntry {
             }
         };
 
-        if io.path_exists(path.clone()).map_err(|e| ErrorKind::IO {
+        if io.path_exists(&path).map_err(|e| ErrorKind::IO {
             path: Some(path.clone()),
             error: e.into(),
         })? {

tvix/eval/src/vm/generators.rs

@@ -421,7 +421,7 @@ impl<'o> VM<'o> {
                         VMRequest::ReadToString(path) => {
                             let content = self
                                 .io_handle
-                                .read_to_string(path.clone())
+                                .read_to_string(&path)
                                 .map_err(|e| ErrorKind::IO {
                                     path: Some(path),
                                     error: e.into(),
@@ -434,7 +434,7 @@ impl<'o> VM<'o> {
                         VMRequest::PathExists(path) => {
                             let exists = self
                                 .io_handle
-                                .path_exists(path.clone())
+                                .path_exists(&path)
                                 .map_err(|e| ErrorKind::IO {
                                     path: Some(path),
                                     error: e.into(),
@@ -448,7 +448,7 @@ impl<'o> VM<'o> {
                         VMRequest::ReadDir(path) => {
                             let dir = self
                                 .io_handle
-                                .read_dir(path.clone())
+                                .read_dir(&path)
                                 .map_err(|e| ErrorKind::IO {
                                     path: Some(path),
                                     error: e.into(),