add contexts to Add/Remove methods

We'll need these for slower/remote datastores.

batch.go

 package format
 
 import (
+	"context"
 	"runtime"
 
 	cid "github.com/ipfs/go-cid"
@@ -71,7 +72,7 @@ func (t *Batch) asyncCommit() {
 		}
 	}
 	go func(b []Node) {
-		err := t.ds.AddMany(b)
+		err := t.ds.AddMany(context.Background(), b)
 		t.commitResults <- err
 	}(t.nodes)
 

batch_test.go

@@ -41,14 +41,14 @@ func (d *testDag) GetMany(ctx context.Context, cids []*cid.Cid) <-chan *NodeOpti
 	return out
 }
 
-func (d *testDag) Add(node Node) error {
+func (d *testDag) Add(ctx context.Context, node Node) error {
 	d.mu.Lock()
 	defer d.mu.Unlock()
 	d.nodes[node.Cid().KeyString()] = node
 	return nil
 }
 
-func (d *testDag) AddMany(nodes []Node) error {
+func (d *testDag) AddMany(ctx context.Context, nodes []Node) error {
 	d.mu.Lock()
 	defer d.mu.Unlock()
 	for _, n := range nodes {
@@ -57,14 +57,14 @@ func (d *testDag) AddMany(nodes []Node) error {
 	return nil
 }
 
-func (d *testDag) Remove(c *cid.Cid) error {
+func (d *testDag) Remove(ctx context.Context, c *cid.Cid) error {
 	d.mu.Lock()
 	defer d.mu.Unlock()
 	delete(d.nodes, c.KeyString())
 	return nil
 }
 
-func (d *testDag) RemoveMany(cids []*cid.Cid) error {
+func (d *testDag) RemoveMany(ctx context.Context, cids []*cid.Cid) error {
 	d.mu.Lock()
 	defer d.mu.Unlock()
 	for _, c := range cids {

merkledag.go

@@ -43,21 +43,21 @@ type DAGService interface {
 	NodeGetter
 
 	// Add adds a node to this DAG.
-	Add(Node) error
+	Add(context.Context, Node) error
 
 	// Remove removes a node from this DAG.
 	//
 	// Remove returns no error if the requested node is not present in this DAG.
-	Remove(*cid.Cid) error
+	Remove(context.Context, *cid.Cid) error
 
 	// AddMany adds many nodes to this DAG.
 	//
 	// Consider using NewBatch instead of calling this directly if you need
 	// to add an unbounded number of nodes to avoid buffering too much.
-	AddMany([]Node) error
+	AddMany(context.Context, []Node) error
 
 	// RemoveMany removes many nodes from this DAG.
 	//
 	// It returns success even if the nodes were not present in the DAG.
-	RemoveMany([]*cid.Cid) error
+	RemoveMany(context.Context, []*cid.Cid) error
 }