Basic walk_directories implementation

crates/ruff_db/Cargo.toml

@@ -31,4 +31,4 @@ insta = { workspace = true }
 tempfile = { workspace = true }
 
 [features]
-os = []
+os = ["ignore"]

crates/ruff_db/src/system.rs

@@ -1,8 +1,10 @@
+use std::fmt::Debug;
+
 pub use memory_fs::MemoryFileSystem;
 #[cfg(feature = "os")]
 pub use os::OsSystem;
-use std::fmt::Debug;
 pub use test::{DbWithTestSystem, TestSystem};
+use walk_directory::WalkDirectoryBuilder;
 
 use crate::file_revision::FileRevision;
 
@@ -13,6 +15,7 @@ mod memory_fs;
 mod os;
 mod path;
 mod test;
+pub mod walk_directory;
 
 pub type Result<T> = std::io::Result<T>;
 
@@ -85,6 +88,9 @@ pub trait System: Debug {
         path: &SystemPath,
     ) -> Result<Box<dyn Iterator<Item = Result<DirectoryEntry>> + 'a>>;
 
+    /// Recursively walks the content of `path`.
+    fn walk_directory(&self, path: &SystemPath) -> WalkDirectoryBuilder;
+
     fn as_any(&self) -> &dyn std::any::Any;
 }
 
@@ -133,20 +139,20 @@ impl FileType {
 #[derive(Debug)]
 pub struct DirectoryEntry {
     path: SystemPathBuf,
-    file_type: Result<FileType>,
+    file_type: FileType,
 }
 
 impl DirectoryEntry {
-    pub fn new(path: SystemPathBuf, file_type: Result<FileType>) -> Self {
+    pub fn new(path: SystemPathBuf, file_type: FileType) -> Self {
         Self { path, file_type }
     }
 
     pub fn path(&self) -> &SystemPath {
         &self.path
     }
 
-    pub fn file_type(&self) -> &Result<FileType> {
-        &self.file_type
+    pub fn file_type(&self) -> FileType {
+        self.file_type
     }
 }