parallel works

Cargo.lock

@@ -232,6 +232,17 @@ dependencies = [
  "slab",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.1.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc587bc0ec293155d5bfa6b9891ec18a1e330c234f896ea47fbada4cadbe47e6"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "wasi",
+]
+
 [[package]]
 name = "gimli"
 version = "0.22.0"
@@ -453,6 +464,12 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c36fa947111f5c62a733b652544dd0016a43ce89619538a8ef92724a6f501a20"
+
 [[package]]
 name = "pretty_env_logger"
 version = "0.4.0"
@@ -499,6 +516,47 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rand"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
+dependencies = [
+ "getrandom",
+ "libc",
+ "rand_chacha",
+ "rand_core",
+ "rand_hc",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+dependencies = [
+ "getrandom",
+]
+
+[[package]]
+name = "rand_hc"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
+dependencies = [
+ "rand_core",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.1.57"
@@ -560,10 +618,12 @@ dependencies = [
  "cfg-if",
  "color-eyre",
  "futures",
+ "lazy_static",
  "log",
  "pretty_env_logger",
  "rustc_version",
  "tokio",
+ "uuid",
 ]
 
 [[package]]
@@ -664,6 +724,21 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f7fe0bb3479651439c9112f72b6c505038574c9fbb575ed1bf3b797fa39dd564"
 
+[[package]]
+name = "uuid"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9fde2f6a4bea1d6e007c4ad38c6839fa71cbb63b6dbf5b595aa38dc9b1093c11"
+dependencies = [
+ "rand",
+]
+
+[[package]]
+name = "wasi"
+version = "0.9.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
+
 [[package]]
 name = "winapi"
 version = "0.2.8"

Cargo.toml

@@ -24,6 +24,8 @@ log = "0.4.11"
 pretty_env_logger = "0.4.0"
 color-eyre = {version = "0.5.6", default-features=false}
 futures = {version = "0.3.5", optional = true}
+lazy_static = "1.4.0"
+uuid = {version = "0.8.1", features = ["v4"]}
 
 [build-dependencies]
 rustc_version = "0.2"

src/error.rs

@@ -12,6 +12,8 @@ pub enum ErrorKind
     Stat(io::Error),
     Open(io::Error),
     Copy(io::Error),
+    Unlink(io::Error),
+    Move(io::Error),
 }
 
 impl ErrorKind
@@ -75,6 +77,8 @@ impl std::error::Error for Error
 	    ErrorKind::Stat(io) => io,
 	    ErrorKind::Open(io) => io,
 	    ErrorKind::Copy(io) => io,
+	    ErrorKind::Unlink(io) => io,
+	    ErrorKind::Move(io) => io,
 	   // _ => return None,
 	})
     }
@@ -86,7 +90,9 @@ impl std::fmt::Display for Error
 	match &self.kind {
 	    ErrorKind::Stat(_) => write!(f, "Failed to stat file {:?}", self.path),
 	    ErrorKind::Open(_) => write!(f, "Failed to open file {:?}", self.path),
-	    ErrorKind::Copy(_) => write!(f, "Failed to create copy of file {:?}", self.path),
+	    ErrorKind::Copy(_) => write!(f, "Failed to create copy of file to temp location {:?}", self.path),
+	    ErrorKind::Unlink(_) => write!(f, "Failed to unlink file {:?}", self.path),
+	    ErrorKind::Move(_) => write!(f, "Failed to move new file into place {:?}", self.path),
 	}
     }
 }

src/main.rs

@@ -7,6 +7,7 @@ use color_eyre::{
     eyre::{self, eyre, WrapErr},
     Help, SectionExt,
 };
+use lazy_static::lazy_static;
 
 fn init() -> eyre::Result<()>
 {
@@ -16,6 +17,7 @@ fn init() -> eyre::Result<()>
     Ok(())
 }
 
+mod temp;
 mod error;
 
 #[cfg(feature="parallel")]

src/parallel.rs

@@ -36,17 +36,13 @@ fn gensem() -> Option<Arc<Semaphore>>
     }
 }
 
-fn tpath() -> String
-{
-    todo!();
-    ".test.tmp".to_owned()
-}
-
 async fn unlink(path: &Path) -> Result<(), Error>
 {
-    let tmp = path.parent().unwrap().join(tpath());
+    let tmp = temp::TempFile::new_in(path.parent().unwrap());
-    fs::copy(path, tmp).await.map_err(|e| Error::new(ErrorKind::Copy(e), path.to_owned()))?;
+    fs::copy(path, &tmp).await.map_err(|e| Error::new(ErrorKind::Copy(e), path.to_owned()))?;
-    todo!();
+    fs::remove_file(path).await.map_err(|e| Error::new(ErrorKind::Unlink(e), path.to_owned()))?;
+    fs::rename(&tmp, path).await.map_err(|e| Error::new(ErrorKind::Move(e), path.to_owned()))?;
+    tmp.release(); // file no longer exists, so no need to drop;
     Ok(())
 }
 

src/temp.rs

@@ -0,0 +1,82 @@
+//! Temp file
+use super::*;
+use std::{
+    ops::Drop,
+    path::{
+	Path,
+	PathBuf,
+    },
+};
+
+lazy_static! {
+    static ref DEFAULT_LOCATION: PathBuf = std::env::temp_dir();
+}
+
+fn genname() -> String
+{
+    uuid::Uuid::new_v4().to_string()
+}
+
+#[derive(Debug)]
+pub struct TempFile(Option<PathBuf>);
+
+impl TempFile
+{
+    /// Create a new instance in default temp location
+    pub fn new() -> Self
+    {
+	Self::new_in(&*DEFAULT_LOCATION)
+    }
+    /// Create a new instance with random name in this location
+    pub fn new_in<P: AsRef<Path>>(dir: P) -> Self
+    {
+	Self::new_path(dir.as_ref().join(genname()))
+    }
+    /// Create a new instance from a specific path
+    pub fn new_path<P: Into<PathBuf>>(path: P) -> Self
+    {
+	let path = path.into();
+	trace!("Creating temp owned path {:?}", path);
+	Self(Some(path))
+    }
+
+    /// The internal path
+    pub fn path(&self) -> &Path
+    {
+	(&self.0).as_ref().unwrap()
+    }
+
+    /// Release ownership of the path, not deleting the file if it exists
+    pub fn release(mut self) -> PathBuf
+    {
+	let d = self.0.take().unwrap();
+	std::mem::forget(self);
+	d
+    }
+
+    /// Attempt to remove this temp file async
+    pub async fn drop_async(mut self) -> tokio::io::Result<()>
+    {
+	let res = tokio::fs::remove_file(self.0.take().unwrap()).await;
+	std::mem::forget(self);
+	res
+    }
+}
+
+impl AsRef<Path> for TempFile
+{
+    #[inline] fn as_ref(&self) -> &Path
+    {
+	self.path()
+    }
+}
+
+impl Drop for TempFile
+{
+    fn drop(&mut self)
+    {
+	if let Err(e) = std::fs::remove_file(self.0.take().unwrap()) {
+	    debug!("Failed to remove owned temp file (sync, drop): {}", e);
+	}
+    }
+}