feat(bitswap) make offline exchange query datastore

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>

offline.go

@@ -3,42 +3,66 @@
 package offline
 
 import (
-	"errors"
-
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
-
 	blocks "github.com/jbenet/go-ipfs/blocks"
+	"github.com/jbenet/go-ipfs/blocks/blockstore"
 	exchange "github.com/jbenet/go-ipfs/exchange"
 	u "github.com/jbenet/go-ipfs/util"
 )
 
-var OfflineMode = errors.New("Block unavailable. Operating in offline mode")
-
-func Exchange() exchange.Interface {
-	return &offlineExchange{}
+func Exchange(bs blockstore.Blockstore) exchange.Interface {
+	return &offlineExchange{bs: bs}
 }
 
 // offlineExchange implements the Exchange interface but doesn't return blocks.
 // For use in offline mode.
-type offlineExchange struct{}
+type offlineExchange struct {
+	bs blockstore.Blockstore
+}
 
 // GetBlock returns nil to signal that a block could not be retrieved for the
 // given key.
 // NB: This function may return before the timeout expires.
-func (_ *offlineExchange) GetBlock(context.Context, u.Key) (*blocks.Block, error) {
-	return nil, OfflineMode
+func (e *offlineExchange) GetBlock(_ context.Context, k u.Key) (*blocks.Block, error) {
+	return e.bs.Get(k)
 }
 
 // HasBlock always returns nil.
-func (_ *offlineExchange) HasBlock(context.Context, *blocks.Block) error {
-	return nil
+func (e *offlineExchange) HasBlock(_ context.Context, b *blocks.Block) error {
+	return e.bs.Put(b)
 }
 
 // Close always returns nil.
 func (_ *offlineExchange) Close() error {
+	// NB: exchange doesn't own the blockstore's underlying datastore, so it is
+	// not responsible for closing it.
 	return nil
 }
 
-func (_ *offlineExchange) GetBlocks(context.Context, []u.Key) (<-chan *blocks.Block, error) {
-	return nil, OfflineMode
+func (e *offlineExchange) GetBlocks(ctx context.Context, ks []u.Key) (<-chan *blocks.Block, error) {
+	out := make(chan *blocks.Block, 0)
+	go func() {
+		defer close(out)
+		var misses []u.Key
+		for _, k := range ks {
+			hit, err := e.bs.Get(k)
+			if err != nil {
+				misses = append(misses, k)
+				// a long line of misses should abort when context is cancelled.
+				select {
+				// TODO case send misses down channel
+				case <-ctx.Done():
+					return
+				default:
+					continue
+				}
+			}
+			select {
+			case out <- hit:
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+	return out, nil
 }

offline_test.go

@@ -4,13 +4,16 @@ import (
 	"testing"
 
 	context "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/go.net/context"
-
+	ds "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore"
+	ds_sync "github.com/jbenet/go-ipfs/Godeps/_workspace/src/github.com/jbenet/go-datastore/sync"
 	blocks "github.com/jbenet/go-ipfs/blocks"
+	"github.com/jbenet/go-ipfs/blocks/blockstore"
+	"github.com/jbenet/go-ipfs/blocks/blocksutil"
 	u "github.com/jbenet/go-ipfs/util"
 )
 
 func TestBlockReturnsErr(t *testing.T) {
-	off := Exchange()
+	off := Exchange(bstore())
 	_, err := off.GetBlock(context.Background(), u.Key("foo"))
 	if err != nil {
 		return // as desired
@@ -19,10 +22,56 @@ func TestBlockReturnsErr(t *testing.T) {
 }
 
 func TestHasBlockReturnsNil(t *testing.T) {
-	off := Exchange()
+	store := bstore()
+	ex := Exchange(store)
 	block := blocks.NewBlock([]byte("data"))
-	err := off.HasBlock(context.Background(), block)
+
+	err := ex.HasBlock(context.Background(), block)
 	if err != nil {
-		t.Fatal("")
+		t.Fail()
+	}
+
+	if _, err := store.Get(block.Key()); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestGetBlocks(t *testing.T) {
+	store := bstore()
+	ex := Exchange(store)
+	g := blocksutil.NewBlockGenerator()
+
+	expected := g.Blocks(2)
+
+	for _, b := range expected {
+		if err := ex.HasBlock(context.Background(), b); err != nil {
+			t.Fail()
+		}
 	}
+
+	request := func() []u.Key {
+		var ks []u.Key
+
+		for _, b := range expected {
+			ks = append(ks, b.Key())
+		}
+		return ks
+	}()
+
+	received, err := ex.GetBlocks(context.Background(), request)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var count int
+	for _ = range received {
+		count++
+	}
+	if len(expected) != count {
+		t.Fail()
+	}
+}
+
+func bstore() blockstore.Blockstore {
+	return blockstore.NewBlockstore(ds_sync.MutexWrap(ds.NewMapDatastore()))
 }