find: New WalkEntry wrapper

The new type wraps DirEntry when possible, but also lets us pass a valid
entry to matchers when walkdir returns a broken symlink error.  It also
implements a Metadata cache (part of uutils#430).

src/find/matchers/access.rs

@@ -5,9 +5,8 @@
 // https://opensource.org/licenses/MIT.
 
 use faccess::PathExt;
-use walkdir::DirEntry;
 
-use super::{Matcher, MatcherIO};
+use super::{Matcher, MatcherIO, WalkEntry};
 
 /// Matcher for -{read,writ,execut}able.
 pub enum AccessMatcher {
@@ -17,7 +16,7 @@ pub enum AccessMatcher {
 }
 
 impl Matcher for AccessMatcher {
-    fn matches(&self, file_info: &DirEntry, _: &mut MatcherIO) -> bool {
+    fn matches(&self, file_info: &WalkEntry, _: &mut MatcherIO) -> bool {
         let path = file_info.path();
 
         match self {

src/find/matchers/delete.rs

@@ -7,13 +7,11 @@
  * file that was distributed with this source code.
  */
 
-use std::fs::{self, FileType};
+use std::fs;
 use std::io::{self, stderr, Write};
 use std::path::Path;
 
-use walkdir::DirEntry;
-
-use super::{Matcher, MatcherIO};
+use super::{FileType, Matcher, MatcherIO, WalkEntry};
 
 pub struct DeleteMatcher;
 
@@ -32,7 +30,7 @@ impl DeleteMatcher {
 }
 
 impl Matcher for DeleteMatcher {
-    fn matches(&self, file_info: &DirEntry, _: &mut MatcherIO) -> bool {
+    fn matches(&self, file_info: &WalkEntry, _: &mut MatcherIO) -> bool {
         let path = file_info.path();
         let path_str = path.to_string_lossy();
 

src/find/matchers/empty.rs

@@ -9,7 +9,7 @@ use std::{
     io::{stderr, Write},
 };
 
-use super::Matcher;
+use super::{Matcher, MatcherIO, WalkEntry};
 
 pub struct EmptyMatcher;
 
@@ -20,7 +20,7 @@ impl EmptyMatcher {
 }
 
 impl Matcher for EmptyMatcher {
-    fn matches(&self, file_info: &walkdir::DirEntry, _: &mut super::MatcherIO) -> bool {
+    fn matches(&self, file_info: &WalkEntry, _: &mut MatcherIO) -> bool {
         if file_info.file_type().is_file() {
             match file_info.metadata() {
                 Ok(meta) => meta.len() == 0,