Add erasure coding to ObjectFetcher

shared/subspace-data-retrieval/src/object_fetcher.rs

@@ -23,6 +23,7 @@ use subspace_archiving::archiver::{Segment, SegmentItem};
 use subspace_core_primitives::{
     Piece, PieceIndex, RawRecord, RecordedHistorySegment, SegmentIndex,
 };
+use subspace_erasure_coding::ErasureCoding;
 use tracing::{debug, trace};
 
 /// Object fetching errors.
@@ -128,21 +129,29 @@ pub struct ObjectFetcher {
     /// The piece getter used to fetch pieces.
     piece_getter: Arc<dyn DsnSyncPieceGetter + Send + Sync + 'static>,
 
+    /// The erasure coding configuration of those pieces.
+    erasure_coding: ErasureCoding,
+
     /// The maximum number of data bytes we'll read for a single object.
     max_object_len: usize,
 }
 
 impl ObjectFetcher {
-    /// Create a new object fetcher with the given piece getter.
+    /// Create a new object fetcher with the given configuration.
     ///
     /// `max_object_len` is the amount of data bytes we'll read for a single object before giving
     /// up and returning an error, or `None` for no limit (`usize::MAX`).
-    pub fn new<PG>(piece_getter: PG, max_object_len: Option<usize>) -> Self
+    pub fn new<PG>(
+        piece_getter: PG,
+        erasure_coding: ErasureCoding,
+        max_object_len: Option<usize>,
+    ) -> Self
     where
         PG: DsnSyncPieceGetter + Send + Sync + 'static,
     {
         Self {
             piece_getter: Arc::new(piece_getter),
+            erasure_coding,
             max_object_len: max_object_len.unwrap_or(usize::MAX),
         }
     }
@@ -440,7 +449,12 @@ impl ObjectFetcher {
 
     /// Read the whole segment by its index (just records, skipping witnesses).
     async fn read_segment(&self, segment_index: SegmentIndex) -> Result<Segment, Error> {
-        Ok(download_segment(segment_index, &self.piece_getter).await?)
+        Ok(download_segment(
+            segment_index,
+            &self.piece_getter,
+            self.erasure_coding.clone(),
+        )
+        .await?)
     }
 
     /// Concurrently read multiple pieces by their indexes

shared/subspace-data-retrieval/src/segment_fetcher.rs

@@ -54,13 +54,12 @@ pub enum SegmentGetterError {
 pub async fn download_segment<PG>(
     segment_index: SegmentIndex,
     piece_getter: &PG,
+    erasure_coding: ErasureCoding,
 ) -> Result<Segment, SegmentGetterError>
 where
     PG: DsnSyncPieceGetter,
 {
-    let reconstructor = Reconstructor::new(
-        /*TODO*/ ErasureCoding::new(1.try_into().unwrap()).unwrap(),
-    );
+    let reconstructor = Reconstructor::new(erasure_coding);
 
     let segment_pieces = download_segment_pieces(segment_index, piece_getter).await?;