Avoid copy in MountStack

src/main.rs

@@ -67,7 +67,6 @@ fn create(command: CreateCommand) -> Result<(), Error> {
     let genfstab = Tool::find("genfstab")?;
     let mkfat = Tool::find("mkfs.fat")?;
     let mkbtrfs = Tool::find("mkfs.btrfs")?;
-    let mut mount_stack = MountStack::new();
 
     if !(command.disk.starts_with("/dev/disk/by-id")
         && (command
@@ -81,6 +80,8 @@ fn create(command: CreateCommand) -> Result<(), Error> {
     }
 
     let mount_point = tempdir().context(ErrorKind::TmpDirError)?;
+    let boot_point = mount_point.path().join("boot");
+    let mut mount_stack = MountStack::new();
 
     info!("Partitioning the disk");
     sgdisk
@@ -119,7 +120,6 @@ fn create(command: CreateCommand) -> Result<(), Error> {
             Some("compress=zstd"),
         ).context(ErrorKind::Mounting)?;
 
-    let boot_point = mount_point.path().join("boot");
     fs::create_dir(&boot_point).context(ErrorKind::CreateBoot)?;
 
     mount_stack
@@ -193,8 +193,6 @@ fn create(command: CreateCommand) -> Result<(), Error> {
     }
 
     info!("Unmounting filesystems");
-    drop(mount_stack);
-
     Ok(())
 }
 

src/mountstack.rs

@@ -1,6 +1,6 @@
 use nix;
 use nix::mount::{mount, umount, MsFlags};
-use std::path::{Path, PathBuf};
+use std::path::Path;
 
 #[derive(Debug)]
 pub enum Filesystem {
@@ -9,7 +9,7 @@ pub enum Filesystem {
 }
 
 impl Filesystem {
-    fn to_type(self) -> &'static str {
+    fn to_type(&self) -> &'static str {
         match self {
             Filesystem::Btrfs => "btrfs",
             Filesystem::Vfat => "vfat",
@@ -17,11 +17,11 @@ impl Filesystem {
     }
 }
 
-pub struct MountStack {
-    targets: Vec<PathBuf>,
+pub struct MountStack<'a> {
+    targets: Vec<&'a Path>,
 }
 
-impl MountStack {
+impl<'a> MountStack<'a> {
     pub fn new() -> Self {
         MountStack {
             targets: Vec::new(),
@@ -32,7 +32,7 @@ impl MountStack {
     pub fn mount(
         &mut self,
         source: &Path,
-        target: &Path,
+        target: &'a Path,
         filesystem: Filesystem,
         options: Option<&str>,
     ) -> nix::Result<()> {
@@ -44,16 +44,16 @@ impl MountStack {
             MsFlags::empty(),
             options,
         )?;
-        self.targets.push(target.to_owned());
+        self.targets.push(target);
         Ok(())
     }
 }
 
-impl Drop for MountStack {
+impl<'a> Drop for MountStack<'a> {
     fn drop(&mut self) {
         while let Some(target) = self.targets.pop() {
             debug!("Unmounting {}", target.display());
-            if !umount(&target).is_ok() {
+            if !umount(target).is_ok() {
                 warn!("Unable to mount {}", target.display());
             };
         }