diff/restore: Treat single file destination properly

src/backend/local.rs

@@ -146,7 +146,39 @@ impl WriteBackend for LocalBackend {
     }
 }
 
-impl LocalBackend {
+#[derive(Clone)]
+pub struct LocalDestination {
+    path: PathBuf,
+    is_file: bool,
+}
+
+impl LocalDestination {
+    pub fn new(path: &str, create: bool, expect_file: bool) -> Result<Self> {
+        let is_dir = path.ends_with('/');
+        let path: PathBuf = path.into();
+        let is_file = path.is_file() || (!path.is_dir() && !is_dir && expect_file);
+
+        if create {
+            if is_file {
+                if let Some(path) = path.parent() {
+                    fs::create_dir_all(path)?;
+                }
+            } else {
+                fs::create_dir_all(&path)?;
+            }
+        }
+
+        Ok(Self { path, is_file })
+    }
+
+    fn path(&self, item: impl AsRef<Path>) -> PathBuf {
+        if self.is_file {
+            self.path.clone()
+        } else {
+            self.path.join(item)
+        }
+    }
+
     pub fn remove_dir(&self, dirname: impl AsRef<Path>) -> Result<()> {
         Ok(fs::remove_dir_all(dirname)?)
     }
@@ -162,7 +194,7 @@ impl LocalBackend {
     }
 
     pub fn set_times(&self, item: impl AsRef<Path>, meta: &Metadata) -> Result<()> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
         if let Some(mtime) = meta.mtime.map(|t| FileTime::from_system_time(t.into())) {
             set_file_mtime(&filename, mtime)?;
         }
@@ -173,7 +205,7 @@ impl LocalBackend {
     }
 
     pub fn set_user_group(&self, item: impl AsRef<Path>, meta: &Metadata) -> Result<()> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
 
         let user = meta
             .user
@@ -195,7 +227,7 @@ impl LocalBackend {
     }
 
     pub fn set_uid_gid(&self, item: impl AsRef<Path>, meta: &Metadata) -> Result<()> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
 
         let uid = meta.uid.map(Uid::from_raw);
         let gid = meta.gid.map(Gid::from_raw);
@@ -205,7 +237,7 @@ impl LocalBackend {
     }
 
     pub fn set_permission(&self, item: impl AsRef<Path>, meta: &Metadata) -> Result<()> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
 
         if let Some(mode) = meta.mode() {
             let mode = map_mode_from_go(*mode);
@@ -216,7 +248,7 @@ impl LocalBackend {
 
     // set_length sets the length of the given file. If it doesn't exist, create a new (empty) one with given length
     pub fn set_length(&self, item: impl AsRef<Path>, size: u64) -> Result<()> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
         OpenOptions::new()
             .create(true)
             .write(true)
@@ -226,7 +258,7 @@ impl LocalBackend {
     }
 
     pub fn create_special(&self, item: impl AsRef<Path>, node: &Node) -> Result<()> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
 
         match node.node_type() {
             NodeType::Symlink { linktarget } => {
@@ -270,7 +302,7 @@ impl LocalBackend {
     }
 
     pub fn read_at(&self, item: impl AsRef<Path>, offset: u64, length: u64) -> Result<Bytes> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
         let mut file = File::open(filename)?;
         file.seek(SeekFrom::Start(offset))?;
         let mut vec = vec![0; length.try_into()?];
@@ -279,7 +311,7 @@ impl LocalBackend {
     }
 
     pub fn get_matching_file(&self, item: impl AsRef<Path>, size: u64) -> Option<File> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
         match fs::symlink_metadata(&filename) {
             Ok(meta) => {
                 if meta.is_file() && meta.len() == size {
@@ -293,7 +325,7 @@ impl LocalBackend {
     }
 
     pub fn write_at(&self, item: impl AsRef<Path>, offset: u64, data: &[u8]) -> Result<()> {
-        let filename = self.path.join(item);
+        let filename = self.path(item);
         let file = fs::OpenOptions::new()
             .create(true)
             .write(true)

src/commands/diff.rs

@@ -5,7 +5,7 @@ use anyhow::{anyhow, bail, Context, Result};
 use clap::Parser;
 
 use super::{progress_counter, RusticConfig};
-use crate::backend::{LocalBackend, LocalSource, LocalSourceOptions};
+use crate::backend::{LocalDestination, LocalSource, LocalSourceOptions};
 use crate::blob::{Node, NodeStreamer, NodeType, Tree};
 use crate::commands::helpers::progress_spinner;
 use crate::crypto::hash;
@@ -79,7 +79,7 @@ pub(super) fn execute(
 
             let index = IndexBackend::new(be, progress_counter(""))?;
             let node1 = Tree::node_from_path(&index, snap1.tree, Path::new(path1))?;
-            let local = LocalBackend::new(path2)?;
+            let local = LocalDestination::new(path2, false, !node1.is_dir())?;
             let path2 = PathBuf::from(path2);
             let is_dir = path2
                 .metadata()
@@ -123,7 +123,7 @@ fn arg_to_snap_path<'a>(arg: &'a str, default_path: &'a str) -> (Option<&'a str>
 }
 
 fn identical_content_local(
-    local: &LocalBackend,
+    local: &LocalDestination,
     index: &impl ReadIndex,
     path: &Path,
     node: &Node,

src/commands/restore.rs

@@ -15,7 +15,7 @@ use rayon::ThreadPoolBuilder;
 
 use super::rustic_config::RusticConfig;
 use super::{bytes, progress_bytes, progress_counter, warm_up_wait};
-use crate::backend::{DecryptReadBackend, FileType, LocalBackend};
+use crate::backend::{DecryptReadBackend, FileType, LocalDestination};
 use crate::blob::{Node, NodeStreamer, NodeType, Tree};
 use crate::commands::helpers::progress_spinner;
 use crate::crypto::hash;
@@ -89,7 +89,7 @@ pub(super) fn execute(
     let index = IndexBackend::new(be, progress_counter(""))?;
     let node = Tree::node_from_path(&index, snap.tree, Path::new(path))?;
 
-    let dest = LocalBackend::new(&opts.dest)?;
+    let dest = LocalDestination::new(&opts.dest, true, !node.is_dir())?;
 
     let p = progress_spinner("collecting file information...");
     let (file_infos, stats) = allocate_and_collect(&dest, index.clone(), &node, &opts)?;
@@ -150,7 +150,7 @@ struct RestoreStats {
 
 /// collect restore information, scan existing files and allocate non-existing files
 fn allocate_and_collect(
-    dest: &LocalBackend,
+    dest: &LocalDestination,
     index: impl IndexedBackend + Unpin,
     node: &Node,
     opts: &Opts,
@@ -332,7 +332,7 @@ fn allocate_and_collect(
 /// using the [`DecryptReadBackend`] `be` and writing them into the [`LocalBackend`] `dest`.
 fn restore_contents(
     be: &impl DecryptReadBackend,
-    dest: &LocalBackend,
+    dest: &LocalDestination,
     file_infos: FileInfos,
 ) -> Result<()> {
     let (filenames, restore_info, total_size, _) = file_infos.dissolve();
@@ -400,7 +400,7 @@ fn restore_contents(
 }
 
 fn restore_metadata(
-    dest: &LocalBackend,
+    dest: &LocalDestination,
     index: impl IndexedBackend + Unpin,
     node: &Node,
     opts: &Opts,
@@ -435,7 +435,7 @@ fn restore_metadata(
     Ok(())
 }
 
-fn set_metadata(dest: &LocalBackend, path: &PathBuf, node: &Node, opts: &Opts) {
+fn set_metadata(dest: &LocalDestination, path: &PathBuf, node: &Node, opts: &Opts) {
     debug!("setting metadata for {:?}", path);
     dest.create_special(path, node)
         .unwrap_or_else(|_| warn!("restore {:?}: creating special file failed.", path));
@@ -512,7 +512,7 @@ impl FileInfos {
     /// Returns the computed length of the file
     fn add_file(
         &mut self,
-        dest: &LocalBackend,
+        dest: &LocalDestination,
         file: &Node,
         name: PathBuf,
         index: &impl IndexedBackend,