Auto merge of #12636 - ehuss:fs-metadata-wrappers, r=weihanglo

Add wrappers around std::fs::metadata

This adds wrappers around `std::fs::metadata` and `std::fs::symlink_metadata` which provide better error messages indicating the path that caused the error. This just helps clean up some duplicated code, and is also going to be used to assist with some code changes in #12634.

crates/cargo-util/src/paths.rs

@@ -4,7 +4,7 @@ use anyhow::{Context, Result};
 use filetime::FileTime;
 use std::env;
 use std::ffi::{OsStr, OsString};
-use std::fs::{self, File, OpenOptions};
+use std::fs::{self, File, Metadata, OpenOptions};
 use std::io;
 use std::io::prelude::*;
 use std::iter;
@@ -136,6 +136,24 @@ pub fn resolve_executable(exec: &Path) -> Result<PathBuf> {
     }
 }
 
+/// Returns metadata for a file (follows symlinks).
+///
+/// Equivalent to [`std::fs::metadata`] with better error messages.
+pub fn metadata<P: AsRef<Path>>(path: P) -> Result<Metadata> {
+    let path = path.as_ref();
+    std::fs::metadata(path)
+        .with_context(|| format!("failed to load metadata for path `{}`", path.display()))
+}
+
+/// Returns metadata for a file without following symlinks.
+///
+/// Equivalent to [`std::fs::metadata`] with better error messages.
+pub fn symlink_metadata<P: AsRef<Path>>(path: P) -> Result<Metadata> {
+    let path = path.as_ref();
+    std::fs::symlink_metadata(path)
+        .with_context(|| format!("failed to load metadata for path `{}`", path.display()))
+}
+
 /// Reads a file to a string.
 ///
 /// Equivalent to [`std::fs::read_to_string`] with better error messages.
@@ -216,16 +234,14 @@ pub fn open<P: AsRef<Path>>(path: P) -> Result<File> {
 
 /// Returns the last modification time of a file.
 pub fn mtime(path: &Path) -> Result<FileTime> {
-    let meta =
-        fs::metadata(path).with_context(|| format!("failed to stat `{}`", path.display()))?;
+    let meta = metadata(path)?;
     Ok(FileTime::from_last_modification_time(&meta))
 }
 
 /// Returns the maximum mtime of the given path, recursing into
 /// subdirectories, and following symlinks.
 pub fn mtime_recursive(path: &Path) -> Result<FileTime> {
-    let meta =
-        fs::metadata(path).with_context(|| format!("failed to stat `{}`", path.display()))?;
+    let meta = metadata(path)?;
     if !meta.is_dir() {
         return Ok(FileTime::from_last_modification_time(&meta));
     }
@@ -432,10 +448,7 @@ pub fn remove_dir_all<P: AsRef<Path>>(p: P) -> Result<()> {
 }
 
 fn _remove_dir_all(p: &Path) -> Result<()> {
-    if p.symlink_metadata()
-        .with_context(|| format!("could not get metadata for `{}` to remove", p.display()))?
-        .is_symlink()
-    {
+    if symlink_metadata(p)?.is_symlink() {
         return remove_file(p);
     }
     let entries = p