From 8287b6d45b34f9d7bb13dc6cc07c86eeae271883 Mon Sep 17 00:00:00 2001
From: Nate Maninger <me@n8m.us>
Date: Fri, 6 Oct 2023 11:19:07 -0600
Subject: [PATCH] add blockservice and exchange

---
 cmd/siapfsd/ipfs.go         |  5 +++
 ipfs/blockstore/dag.go      | 85 +++++++++++++++++++++++++++++++++++++
 ipfs/blockstore/exchange.go | 33 ++++++++++++++
 3 files changed, 123 insertions(+)
 create mode 100644 ipfs/blockstore/dag.go
 create mode 100644 ipfs/blockstore/exchange.go

diff --git a/cmd/siapfsd/ipfs.go b/cmd/siapfsd/ipfs.go
index 9a506f3..60ee153 100644
--- a/cmd/siapfsd/ipfs.go
+++ b/cmd/siapfsd/ipfs.go
@@ -8,6 +8,7 @@ import (
 
 	iface "github.com/ipfs/boxo/coreiface"
 	"github.com/ipfs/boxo/coreiface/options"
+	"github.com/ipfs/boxo/ipld/merkledag"
 	"github.com/ipfs/kubo/config"
 	"github.com/ipfs/kubo/core"
 	"github.com/ipfs/kubo/core/coreapi"
@@ -70,7 +71,11 @@ func createNode(ctx context.Context, repoPath string, db *badger.Store, renterd
 		return nil, nil, fmt.Errorf("failed to create node: %w", err)
 	}
 
+	bs := blockstore.New(bucket, db, cfg.Renterd)
+	bserv := blockstore.NewBlockstoreService(bs)
 	node.Blockstore = blockstore.New(bucket, db, cfg.Renterd)
+	node.DAG = merkledag.NewDAGService(bserv)
+
 	coreAPI, err := coreapi.NewCoreAPI(node)
 	if err != nil {
 		return nil, nil, fmt.Errorf("failed to create coreapi: %w", err)
diff --git a/ipfs/blockstore/dag.go b/ipfs/blockstore/dag.go
new file mode 100644
index 0000000..1fcc081
--- /dev/null
+++ b/ipfs/blockstore/dag.go
@@ -0,0 +1,85 @@
+package blockstore
+
+import (
+	"context"
+	"errors"
+
+	"github.com/ipfs/boxo/blockstore"
+	"github.com/ipfs/boxo/exchange"
+	blocks "github.com/ipfs/go-block-format"
+	cid "github.com/ipfs/go-cid"
+)
+
+type BlockService struct {
+	store blockstore.Blockstore
+}
+
+func (bs *BlockService) Close() error {
+	return nil
+}
+
+// GetBlock gets the requested block.
+func (bs *BlockService) GetBlock(ctx context.Context, c cid.Cid) (blocks.Block, error) {
+	return bs.store.Get(ctx, c)
+}
+
+// GetBlocks does a batch request for the given cids, returning blocks as
+// they are found, in no particular order.
+//
+// It may not be able to find all requested blocks (or the context may
+// be canceled). In that case, it will close the channel early. It is up
+// to the consumer to detect this situation and keep track which blocks
+// it has received and which it hasn't.
+func (bs *BlockService) GetBlocks(ctx context.Context, ks []cid.Cid) <-chan blocks.Block {
+	out := make(chan blocks.Block)
+	go func() {
+		defer close(out)
+		for _, k := range ks {
+			b, err := bs.store.Get(ctx, k)
+			if err != nil {
+				continue
+			}
+			select {
+			case out <- b:
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+	return out
+}
+
+// Blockstore returns a reference to the underlying blockstore
+func (bs *BlockService) Blockstore() blockstore.Blockstore {
+	return bs.store
+}
+
+// Exchange returns a reference to the underlying exchange (usually bitswap)
+func (bs *BlockService) Exchange() exchange.Interface {
+	return &Exchange{
+		bserv: bs,
+	}
+}
+
+// AddBlock puts a given block to the underlying datastore
+func (bs *BlockService) AddBlock(ctx context.Context, o blocks.Block) error {
+	return errors.New("cannot put blocks")
+}
+
+// AddBlocks adds a slice of blocks at the same time using batching
+// capabilities of the underlying datastore whenever possible.
+func (bs *BlockService) AddBlocks(ctx context.Context, b []blocks.Block) error {
+	return errors.New("cannot put blocks")
+}
+
+// DeleteBlock deletes the given block from the blockservice.
+func (bs *BlockService) DeleteBlock(ctx context.Context, o cid.Cid) error {
+	return errors.New("cannot delete blocks")
+}
+
+// NewBlockstoreService returns a new BlockService backed by the given blockstore.
+func NewBlockstoreService(bs blockstore.Blockstore) *BlockService {
+	return &BlockService{
+		store: bs,
+	}
+}
diff --git a/ipfs/blockstore/exchange.go b/ipfs/blockstore/exchange.go
new file mode 100644
index 0000000..dab502d
--- /dev/null
+++ b/ipfs/blockstore/exchange.go
@@ -0,0 +1,33 @@
+package blockstore
+
+import (
+	"context"
+
+	blocks "github.com/ipfs/go-block-format"
+	cid "github.com/ipfs/go-cid"
+)
+
+type Exchange struct {
+	bserv *BlockService
+}
+
+func (e *Exchange) Close() error {
+	return nil
+}
+
+// GetBlock returns the block associated with a given cid.
+func (e *Exchange) GetBlock(ctx context.Context, c cid.Cid) (blocks.Block, error) {
+	return e.bserv.GetBlock(ctx, c)
+}
+
+// GetBlocks returns the blocks associated with the given cids.
+// If the requested blocks are not found immediately, this function should hang until
+// they are found. If they can't be found later, it's also acceptable to terminate.
+func (e *Exchange) GetBlocks(ctx context.Context, cids []cid.Cid) (<-chan blocks.Block, error) {
+	return e.bserv.GetBlocks(ctx, cids), nil
+}
+
+// NotifyNewBlocks tells the exchange that new blocks are available and can be served.
+func (e *Exchange) NotifyNewBlocks(ctx context.Context, blocks ...blocks.Block) error {
+	return nil // TODO
+}