feat(file-id): add get_file_id_no_follow() along with low and high-res variants. (#716)

Author: Byron

file-id/src/lib.rs

@@ -27,6 +27,16 @@
 //! let file_id = file_id::get_high_res_file_id(file.path()).unwrap();
 //! println!("{file_id:?}");
 //! ```
+//!
+//! ## Example (Not Following Symlinks/Reparse Points)
+//!
+//! ```
+//! let file = tempfile::NamedTempFile::new().unwrap();
+//!
+//! // Get file ID without following symlinks
+//! let file_id = file_id::get_file_id_no_follow(file.path()).unwrap();
+//! println!("{file_id:?}");
+//! ```
 use std::{fs, io, path::Path};
 
 #[cfg(feature = "serde")]
@@ -122,6 +132,16 @@ pub fn get_file_id(path: impl AsRef<Path>) -> io::Result<FileId> {
     Ok(FileId::new_inode(metadata.dev(), metadata.ino()))
 }
 
+/// Get the `FileId` for the file or directory at `path` without following symlinks
+#[cfg(target_family = "unix")]
+pub fn get_file_id_no_follow(path: impl AsRef<Path>) -> io::Result<FileId> {
+    use std::os::unix::fs::MetadataExt;
+
+    let metadata = fs::symlink_metadata(path.as_ref())?;
+
+    Ok(FileId::new_inode(metadata.dev(), metadata.ino()))
+}
+
 /// Get the `FileId` for the file or directory at `path`
 #[cfg(target_family = "windows")]
 pub fn get_file_id(path: impl AsRef<Path>) -> io::Result<FileId> {
@@ -130,6 +150,14 @@ pub fn get_file_id(path: impl AsRef<Path>) -> io::Result<FileId> {
     unsafe { get_file_info_ex(&file).or_else(|_| get_file_info(&file)) }
 }
 
+/// Get the `FileId` for the file or directory at `path` without following symlinks/reparse points
+#[cfg(target_family = "windows")]
+pub fn get_file_id_no_follow(path: impl AsRef<Path>) -> io::Result<FileId> {
+    let file = open_file_no_follow(path)?;
+
+    unsafe { get_file_info_ex(&file).or_else(|_| get_file_info(&file)) }
+}
+
 /// Get the `FileId` with the low resolution variant for the file or directory at `path`
 #[cfg(target_family = "windows")]
 pub fn get_low_res_file_id(path: impl AsRef<Path>) -> io::Result<FileId> {
@@ -138,6 +166,14 @@ pub fn get_low_res_file_id(path: impl AsRef<Path>) -> io::Result<FileId> {
     unsafe { get_file_info(&file) }
 }
 
+/// Get the `FileId` with the low resolution variant for the file or directory at `path` without following symlinks/reparse points
+#[cfg(target_family = "windows")]
+pub fn get_low_res_file_id_no_follow(path: impl AsRef<Path>) -> io::Result<FileId> {
+    let file = open_file_no_follow(path)?;
+
+    unsafe { get_file_info(&file) }
+}
+
 /// Get the `FileId` with the high resolution variant for the file or directory at `path`
 #[cfg(target_family = "windows")]
 pub fn get_high_res_file_id(path: impl AsRef<Path>) -> io::Result<FileId> {
@@ -146,6 +182,14 @@ pub fn get_high_res_file_id(path: impl AsRef<Path>) -> io::Result<FileId> {
     unsafe { get_file_info_ex(&file) }
 }
 
+/// Get the `FileId` with the high resolution variant for the file or directory at `path` without following symlinks/reparse points
+#[cfg(target_family = "windows")]
+pub fn get_high_res_file_id_no_follow(path: impl AsRef<Path>) -> io::Result<FileId> {
+    let file = open_file_no_follow(path)?;
+
+    unsafe { get_file_info_ex(&file) }
+}
+
 #[cfg(target_family = "windows")]
 unsafe fn get_file_info_ex(file: &fs::File) -> Result<FileId, io::Error> {
     use std::{mem, os::windows::prelude::*};
@@ -202,3 +246,16 @@ fn open_file<P: AsRef<Path>>(path: P) -> io::Result<fs::File> {
         .custom_flags(FILE_FLAG_BACKUP_SEMANTICS)
         .open(path)
 }
+
+#[cfg(target_family = "windows")]
+fn open_file_no_follow<P: AsRef<Path>>(path: P) -> io::Result<fs::File> {
+    use std::{fs::OpenOptions, os::windows::fs::OpenOptionsExt};
+    use windows_sys::Win32::Storage::FileSystem::{
+        FILE_FLAG_BACKUP_SEMANTICS, FILE_FLAG_OPEN_REPARSE_POINT,
+    };
+
+    OpenOptions::new()
+        .access_mode(0)
+        .custom_flags(FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OPEN_REPARSE_POINT)
+        .open(path)
+}

file-id/tests/integration.rs

@@ -0,0 +1,33 @@
+use file_id::{get_file_id, get_file_id_no_follow};
+use std::{fs, io};
+use tempfile::TempDir;
+
+#[test]
+fn test_get_file_id_vs_no_follow() -> io::Result<()> {
+    let temp_dir = TempDir::new()?;
+    let file_path = temp_dir.path().join("test_file.txt");
+    let symlink_path = temp_dir.path().join("test_symlink");
+
+    // Create a test file
+    fs::write(&file_path, "test content")?;
+
+    // Create a symlink to the file
+    #[cfg(target_family = "unix")]
+    std::os::unix::fs::symlink(&file_path, &symlink_path)?;
+
+    #[cfg(target_family = "windows")]
+    std::os::windows::fs::symlink_file(&file_path, &symlink_path)?;
+
+    // Get file IDs
+    let original_file_id = get_file_id(&file_path)?;
+    let symlink_follow_id = get_file_id(&symlink_path)?;
+    let symlink_no_follow_id = get_file_id_no_follow(&symlink_path)?;
+
+    // Following the symlink should give us the same ID as the original file
+    assert_eq!(original_file_id, symlink_follow_id);
+
+    // Not following the symlink should give us a different ID (the symlink's own ID)
+    assert_ne!(original_file_id, symlink_no_follow_id);
+
+    Ok(())
+}