perf: replace .count() from iterators to more performative operations

Author: talis-fb

src/archive/rar.rs

@@ -18,7 +18,7 @@ pub fn unpack_archive(
     password: Option<&[u8]>,
     quiet: bool,
 ) -> crate::Result<usize> {
-    assert!(output_folder.read_dir().expect("dir exists").count() == 0);
+    assert!(output_folder.read_dir().expect("dir exists").next().is_none());
 
     let archive = match password {
         Some(password) => Archive::with_password(archive_path, password),

src/archive/tar.rs

@@ -24,7 +24,7 @@ use crate::{
 /// Unpacks the archive given by `archive` into the folder given by `into`.
 /// Assumes that output_folder is empty
 pub fn unpack_archive(reader: Box<dyn Read>, output_folder: &Path, quiet: bool) -> crate::Result<usize> {
-    assert!(output_folder.read_dir().expect("dir exists").count() == 0);
+    assert!(output_folder.read_dir().expect("dir exists").next().is_none());
     let mut archive = tar::Archive::new(reader);
 
     let mut files_unpacked = 0;

src/archive/zip.rs

@@ -37,7 +37,7 @@ pub fn unpack_archive<R>(
 where
     R: Read + Seek,
 {
-    assert!(output_folder.read_dir().expect("dir exists").count() == 0);
+    assert!(output_folder.read_dir().expect("dir exists").next().is_none());
 
     let mut unpacked_files = 0;
 

src/commands/decompress.rs

@@ -356,7 +356,7 @@ fn smart_unpack(
 
     let files = unpack_fn(temp_dir_path)?;
 
-    let root_contains_only_one_element = fs::read_dir(temp_dir_path)?.count() == 1;
+    let root_contains_only_one_element = fs::read_dir(temp_dir_path)?.take(2).count() == 1;
 
     let (previous_path, mut new_path) = if root_contains_only_one_element {
         // Only one file in the root directory, so we can just move it to the output directory