chore(tvix/store): Use BoxStream type alias

The BoxStream type alias is a more concise and easier to read than
the full `Pin<Box<dyn Stream<Item = ...> + Send + ...>>` type.

Change-Id: I5b7bccfd066ded5557e01f7895f4cf5c4a33bd44
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10677
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Autosubmit: Connor Brewster <cbrewster@hey.com>

tvix/castore/src/directoryservice/grpc.rs

@@ -1,11 +1,10 @@
 use std::collections::HashSet;
-use std::pin::Pin;
 
 use super::{DirectoryPutter, DirectoryService};
 use crate::proto::{self, get_directory_request::ByWhat};
 use crate::{B3Digest, Error};
 use async_stream::try_stream;
-use futures::Stream;
+use futures::stream::BoxStream;
 use tokio::spawn;
 use tokio::sync::mpsc::UnboundedSender;
 use tokio::task::JoinHandle;
@@ -106,7 +105,7 @@ impl DirectoryService for GRPCDirectoryService {
     fn get_recursive(
         &self,
         root_directory_digest: &B3Digest,
-    ) -> Pin<Box<dyn Stream<Item = Result<proto::Directory, Error>> + Send>> {
+    ) -> BoxStream<Result<proto::Directory, Error>> {
         let mut grpc_client = self.grpc_client.clone();
         let root_directory_digest = root_directory_digest.clone();
 

tvix/castore/src/directoryservice/memory.rs

@@ -1,7 +1,6 @@
 use crate::{proto, B3Digest, Error};
-use futures::Stream;
+use futures::stream::BoxStream;
 use std::collections::HashMap;
-use std::pin::Pin;
 use std::sync::{Arc, RwLock};
 use tonic::async_trait;
 use tracing::{instrument, warn};
@@ -73,7 +72,7 @@ impl DirectoryService for MemoryDirectoryService {
     fn get_recursive(
         &self,
         root_directory_digest: &B3Digest,
-    ) -> Pin<Box<dyn Stream<Item = Result<proto::Directory, Error>> + Send>> {
+    ) -> BoxStream<Result<proto::Directory, Error>> {
         traverse_directory(self.clone(), root_directory_digest)
     }
 

tvix/castore/src/directoryservice/mod.rs

@@ -1,6 +1,5 @@
 use crate::{proto, B3Digest, Error};
-use futures::Stream;
-use std::pin::Pin;
+use futures::stream::BoxStream;
 use tonic::async_trait;
 
 mod from_addr;
@@ -44,7 +43,7 @@ pub trait DirectoryService: Send + Sync {
     fn get_recursive(
         &self,
         root_directory_digest: &B3Digest,
-    ) -> Pin<Box<dyn Stream<Item = Result<proto::Directory, Error>> + Send>>;
+    ) -> BoxStream<Result<proto::Directory, Error>>;
 
     /// Allows persisting a closure of [proto::Directory], which is a graph of
     /// connected Directory messages.

tvix/castore/src/directoryservice/sled.rs

@@ -1,10 +1,9 @@
 use crate::directoryservice::DirectoryPutter;
 use crate::proto::Directory;
 use crate::{proto, B3Digest, Error};
-use futures::Stream;
+use futures::stream::BoxStream;
 use prost::Message;
 use std::path::Path;
-use std::pin::Pin;
 use tonic::async_trait;
 use tracing::{instrument, warn};
 
@@ -99,7 +98,7 @@ impl DirectoryService for SledDirectoryService {
     fn get_recursive(
         &self,
         root_directory_digest: &B3Digest,
-    ) -> Pin<Box<(dyn Stream<Item = Result<proto::Directory, Error>> + Send + 'static)>> {
+    ) -> BoxStream<Result<proto::Directory, Error>> {
         traverse_directory(self.clone(), root_directory_digest)
     }
 

tvix/castore/src/directoryservice/utils.rs

@@ -4,19 +4,18 @@ use crate::proto;
 use crate::B3Digest;
 use crate::Error;
 use async_stream::stream;
-use futures::Stream;
+use futures::stream::BoxStream;
 use std::collections::{HashSet, VecDeque};
-use std::pin::Pin;
 use tonic::async_trait;
 use tracing::warn;
 
 /// Traverses a [proto::Directory] from the root to the children.
 ///
 /// This is mostly BFS, but directories are only returned once.
-pub fn traverse_directory<DS: DirectoryService + 'static>(
+pub fn traverse_directory<'a, DS: DirectoryService + 'static>(
     directory_service: DS,
     root_directory_digest: &B3Digest,
-) -> Pin<Box<dyn Stream<Item = Result<proto::Directory, Error>> + Send>> {
+) -> BoxStream<'a, Result<proto::Directory, Error>> {
     // The list of all directories that still need to be traversed. The next
     // element is picked from the front, new elements are enqueued at the
     // back.