feat(tvix/store): eliminate generics in BlobStore r/6269

To construct various stores at runtime, we need to eliminate associated
types from the BlobService trait, and return Box<dyn …> instead of
specific types.

This also means we can't consume self in the close() method, so
everything we write to is put in an Option<>, and during the first close
we take from there.

Change-Id: Ia523b6ab2f2a5276f51cb5d17e81a5925bce69b6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8647
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

2 files changed, 9 insertions, 13 deletions

diff --git a/tvix/store/src/nar/non_caching_calculation_service.rs b/tvix/store/src/nar/non_caching_calculation_service.rs
index 8a080cb4df..b743f264b0 100644
--- a/tvix/store/src/nar/non_caching_calculation_service.rs
+++ b/tvix/store/src/nar/non_caching_calculation_service.rs
@@ -10,22 +10,19 @@ use super::{NARCalculationService, RenderError};
 
 /// A NAR calculation service which simply renders the whole NAR whenever
 /// we ask for the calculation.
-#[derive(Clone)]
-pub struct NonCachingNARCalculationService<BS: BlobService, DS: DirectoryService> {
-    nar_renderer: NARRenderer<BS, DS>,
+pub struct NonCachingNARCalculationService<DS: DirectoryService> {
+    nar_renderer: NARRenderer<DS>,
 }
 
-impl<BS: BlobService, DS: DirectoryService> NonCachingNARCalculationService<BS, DS> {
-    pub fn new(blob_service: BS, directory_service: DS) -> Self {
+impl<DS: DirectoryService> NonCachingNARCalculationService<DS> {
+    pub fn new(blob_service: Box<dyn BlobService>, directory_service: DS) -> Self {
         Self {
             nar_renderer: NARRenderer::new(blob_service, directory_service),
         }
     }
 }
 
-impl<BS: BlobService, DS: DirectoryService> NARCalculationService
-    for NonCachingNARCalculationService<BS, DS>
-{
+impl<DS: DirectoryService> NARCalculationService for NonCachingNARCalculationService<DS> {
     fn calculate_nar(&self, root_node: &proto::node::Node) -> Result<(u64, [u8; 32]), RenderError> {
         let h = Sha256::new();
         let mut cw = CountWrite::from(h);
diff --git a/tvix/store/src/nar/renderer.rs b/tvix/store/src/nar/renderer.rs
index c10f2ddf52..a9a6d989e1 100644
--- a/tvix/store/src/nar/renderer.rs
+++ b/tvix/store/src/nar/renderer.rs
@@ -11,14 +11,13 @@ use tracing::warn;
 
 /// A NAR renderer, using a blob_service, chunk_service and directory_service
 /// to render a NAR to a writer.
-#[derive(Clone)]
-pub struct NARRenderer<BS: BlobService, DS: DirectoryService> {
-    blob_service: BS,
+pub struct NARRenderer<DS: DirectoryService> {
+    blob_service: Box<dyn BlobService>,
     directory_service: DS,
 }
 
-impl<BS: BlobService, DS: DirectoryService> NARRenderer<BS, DS> {
-    pub fn new(blob_service: BS, directory_service: DS) -> Self {
+impl<DS: DirectoryService> NARRenderer<DS> {
+    pub fn new(blob_service: Box<dyn BlobService>, directory_service: DS) -> Self {
         Self {
             blob_service,
             directory_service,