src/tools/parallel_handler.rs: remove lifetime hacks, require 'static

In theory, one can do std::mem::forget, and ignore the drop handler. With
the lifetime hack, this could result in a crash.

So we simply require 'static lifetime now (futures also needs that).

src/backup/verify.rs

@@ -84,7 +84,7 @@ fn verify_index_chunks(
     worker: Arc<WorkerTask>,
 ) -> Result<(), Error> {
 
-    let errors = AtomicUsize::new(0);
+    let errors = Arc::new(AtomicUsize::new(0));
 
     let start_time = Instant::now();
 
@@ -95,7 +95,7 @@ fn verify_index_chunks(
     let datastore2 = Arc::clone(&datastore);
     let corrupt_chunks2 = Arc::clone(&corrupt_chunks);
     let verified_chunks2 = Arc::clone(&verified_chunks);
-    let errors2 = &errors;
+    let errors2 = Arc::clone(&errors);
 
     let decoder_pool = ParallelHandler::new(
         "verify chunk decoder", 4,

src/client/pull.rs

@@ -50,12 +50,13 @@ async fn pull_index_chunks<I: IndexFile>(
             })
     );
 
+    let target2 = target.clone();
     let verify_pool = ParallelHandler::new(
         "sync chunk writer", 4,
-        |(chunk, digest, size): (DataBlob, [u8;32], u64)|  {
+        move |(chunk, digest, size): (DataBlob, [u8;32], u64)|  {
             // println!("verify and write {}", proxmox::tools::digest_to_hex(&digest));
             chunk.verify_unencrypted(size as usize, &digest)?;
-            target.insert_chunk(&chunk, &digest)?;
+            target2.insert_chunk(&chunk, &digest)?;
             Ok(())
        }
     );

src/tools/parallel_handler.rs

@@ -38,11 +38,10 @@ impl<I: Send> SendHandle<I> {
 ///
 /// When done, the 'complete()' method needs to be called to check for
 /// outstanding errors.
-pub struct ParallelHandler<'a, I> {
+pub struct ParallelHandler<I> {
     handles: Vec<JoinHandle<()>>,
     name: String,
     input: Option<SendHandle<I>>,
-    _marker: std::marker::PhantomData<&'a ()>,
 }
 
 impl<I> Clone for SendHandle<I> {
@@ -54,11 +53,11 @@ impl<I> Clone for SendHandle<I> {
     }
 }
 
-impl<'a, I: Send + 'static> ParallelHandler<'a, I> {
+impl<I: Send + 'static> ParallelHandler<I> {
     /// Create a new thread pool, each thread processing incoming data
     /// with 'handler_fn'.
     pub fn new<F>(name: &str, threads: usize, handler_fn: F) -> Self
-        where F: Fn(I) -> Result<(), Error> + Send + Clone + 'a,
+        where F: Fn(I) -> Result<(), Error> + Send + Clone + 'static,
     {
         let mut handles = Vec::new();
         let (input_tx, input_rx) = bounded::<I>(threads);
@@ -68,13 +67,7 @@ impl<'a, I: Send + 'static> ParallelHandler<'a, I> {
         for i in 0..threads {
             let input_rx = input_rx.clone();
             let abort = Arc::clone(&abort);
-
-            // Erase the 'a lifetime bound. This is safe because we
-            // join all thread in the drop handler.
-            let handler_fn: Box<dyn Fn(I) -> Result<(), Error> + Send + 'a> =
-                Box::new(handler_fn.clone());
-            let handler_fn: Box<dyn Fn(I) -> Result<(), Error> + Send + 'static> =
-                unsafe { std::mem::transmute(handler_fn) };
+            let handler_fn = handler_fn.clone();
 
             handles.push(
                 std::thread::Builder::new()
@@ -104,7 +97,6 @@ impl<'a, I: Send + 'static> ParallelHandler<'a, I> {
                 input: input_tx,
                 abort,
             }),
-            _marker: std::marker::PhantomData,
         }
     }
 
@@ -164,7 +156,7 @@ impl<'a, I: Send + 'static> ParallelHandler<'a, I> {
 }
 
 // Note: We make sure that all threads will be joined
-impl<'a, I> Drop for ParallelHandler<'a, I> {
+impl<I> Drop for ParallelHandler<I> {
     fn drop(&mut self) {
         drop(self.input.take());
         while let Some(handle) = self.handles.pop() {