Support using a custom Blockstore

Usually (in Kubo), the Blockstore is just built on top of the datastore.

There are, however, blockstore implementations (i.e StoreTheHash) that are
optimized blockstores and not general purpose datastores.

This commit allows providing a custom blockstore, but initializes everything
as before when set to nil. The signature of New() changes accordingly. A new
option UncachedBlockstore, allows disabling the CachedBlockstore-wrapping that
also happens by default, since some datastores/blockstores include their own
caching and bloom-filters, so this can potentially be making things slower.

examples/litepeer/litepeer.go

@@ -39,7 +39,7 @@ func main() {
 		panic(err)
 	}
 
-	lite, err := ipfslite.New(ctx, ds, h, dht, nil)
+	lite, err := ipfslite.New(ctx, ds, nil, h, dht, nil)
 	if err != nil {
 		panic(err)
 	}

examples/walker/walker.go

@@ -44,7 +44,7 @@ func main() {
 		panic(err)
 	}
 
-	lite, err := ipfslite.New(ctx, ds, h, dht, nil)
+	lite, err := ipfslite.New(ctx, ds, nil, h, dht, nil)
 	if err != nil {
 		panic(err)
 	}

ipfs.go

@@ -55,6 +55,10 @@ type Config struct {
 	Offline bool
 	// ReprovideInterval sets how often to reprovide records to the DHT
 	ReprovideInterval time.Duration
+	// Disables wrapping the blockstore in an ARC cache + Bloomfilter. Use
+	// when the given blockstore or datastore already has caching, or when
+	// caching is not needed.
+	UncachedBlockstore bool
 }
 
 func (cfg *Config) setDefaults() {
@@ -81,13 +85,15 @@ type Peer struct {
 	reprovider      provider.System
 }
 
-// New creates an IPFS-Lite Peer. It uses the given datastore, libp2p Host and
-// Routing (usuall the DHT). The Host and the Routing may be nil if
-// config.Offline is set to true, as they are not used in that case. Peer
-// implements the ipld.DAGService interface.
+// New creates an IPFS-Lite Peer. It uses the given datastore, blockstore,
+// libp2p Host and Routing (usuall the DHT). If the blockstore is nil, the
+// given datastore will be wrapped to create one. The Host and the Routing may
+// be nil if config.Offline is set to true, as they are not used in that
+// case. Peer implements the ipld.DAGService interface.
 func New(
 	ctx context.Context,
-	store datastore.Batching,
+	datastore datastore.Batching,
+	blockstore blockstore.Blockstore,
 	host host.Host,
 	dht routing.Routing,
 	cfg *Config,
@@ -104,10 +110,10 @@ func New(
 		cfg:   cfg,
 		host:  host,
 		dht:   dht,
-		store: store,
+		store: datastore,
 	}
 
-	err := p.setupBlockstore()
+	err := p.setupBlockstore(blockstore)
 	if err != nil {
 		return nil, err
 	}
@@ -131,14 +137,22 @@ func New(
 	return p, nil
 }
 
-func (p *Peer) setupBlockstore() error {
-	bs := blockstore.NewBlockstore(p.store)
+func (p *Peer) setupBlockstore(bs blockstore.Blockstore) error {
+	var err error
+	if bs == nil {
+		bs = blockstore.NewBlockstore(p.store)
+	}
+
+	// Support Identity multihashes.
 	bs = blockstore.NewIdStore(bs)
-	cachedbs, err := blockstore.CachedBlockstore(p.ctx, bs, blockstore.DefaultCacheOpts())
-	if err != nil {
-		return err
+
+	if !p.cfg.UncachedBlockstore {
+		bs, err = blockstore.CachedBlockstore(p.ctx, bs, blockstore.DefaultCacheOpts())
+		if err != nil {
+			return err
+		}
 	}
-	p.bstore = cachedbs
+	p.bstore = bs
 	return nil
 }
 

ipfs_test.go

@@ -79,12 +79,12 @@ func setupPeers(t *testing.T) (p1, p2 *Peer, closer func(t *testing.T)) {
 			}
 		}
 	}
-	p1, err = New(ctx, ds1, h1, dht1, nil)
+	p1, err = New(ctx, ds1, nil, h1, dht1, nil)
 	if err != nil {
 		closer(t)
 		t.Fatal(err)
 	}
-	p2, err = New(ctx, ds2, h2, dht2, nil)
+	p2, err = New(ctx, ds2, nil, h2, dht2, nil)
 	if err != nil {
 		closer(t)
 		t.Fatal(err)