Fixed mount lookup depending on order

mount/mount.go

@@ -5,6 +5,7 @@ package mount
 import (
 	"errors"
 	"io"
+	"sort"
 	"strings"
 
 	"github.com/ipfs/go-datastore"
@@ -21,12 +22,27 @@ type Mount struct {
 	Datastore datastore.Datastore
 }
 
+type MountSlice []Mount
+
+func (m MountSlice) Len() int {
+	return len(m)
+}
+
+func (m MountSlice) Less(i, j int) bool {
+	return m[i].Prefix.String() > m[j].Prefix.String()
+}
+
+func (m MountSlice) Swap(i, j int) {
+	m[i], m[j] = m[j], m[i]
+}
+
 func New(mounts []Mount) *Datastore {
 	// make a copy so we're sure it doesn't mutate
 	m := make([]Mount, len(mounts))
 	for i, v := range mounts {
 		m[i] = v
 	}
+	sort.Sort(MountSlice(m))
 	return &Datastore{mounts: m}
 }
 

mount/mount_test.go

@@ -239,3 +239,40 @@ func TestQuerySimple(t *testing.T) {
 		t.Errorf("did not see wanted key %q in %+v", myKey, entries)
 	}
 }
+
+func TestLookupPrio(t *testing.T) {
+	mapds0 := datastore.NewMapDatastore()
+	mapds1 := datastore.NewMapDatastore()
+
+	m := mount.New([]mount.Mount{
+		{Prefix: datastore.NewKey("/"), Datastore: mapds0},
+		{Prefix: datastore.NewKey("/foo"), Datastore: mapds1},
+	})
+
+	m.Put(datastore.NewKey("/foo/bar"), "123")
+	m.Put(datastore.NewKey("/baz"), "234")
+
+	found, err := mapds0.Has(datastore.NewKey("/baz"))
+	if err != nil {
+		t.Fatalf("Has error: %v", err)
+	}
+	if g, e := found, true; g != e {
+		t.Fatalf("wrong value: %v != %v", g, e)
+	}
+
+	found, err = mapds0.Has(datastore.NewKey("/foo/bar"))
+	if err != nil {
+		t.Fatalf("Has error: %v", err)
+	}
+	if g, e := found, false; g != e {
+		t.Fatalf("wrong value: %v != %v", g, e)
+	}
+
+	found, err = mapds1.Has(datastore.NewKey("/bar"))
+	if err != nil {
+		t.Fatalf("Has error: %v", err)
+	}
+	if g, e := found, true; g != e {
+		t.Fatalf("wrong value: %v != %v", g, e)
+	}
+}

syncmount/mount.go

@@ -5,6 +5,7 @@ package syncmount
 import (
 	"errors"
 	"io"
+	"sort"
 	"strings"
 	"sync"
 
@@ -22,12 +23,27 @@ type Mount struct {
 	Datastore ds.Datastore
 }
 
+type MountSlice []Mount
+
+func (m MountSlice) Len() int {
+	return len(m)
+}
+
+func (m MountSlice) Less(i, j int) bool {
+	return m[i].Prefix.String() > m[j].Prefix.String()
+}
+
+func (m MountSlice) Swap(i, j int) {
+	m[i], m[j] = m[j], m[i]
+}
+
 func New(mounts []Mount) *Datastore {
 	// make a copy so we're sure it doesn't mutate
 	m := make([]Mount, len(mounts))
 	for i, v := range mounts {
 		m[i] = v
 	}
+	sort.Sort(MountSlice(m))
 	return &Datastore{mounts: m}
 }
 

syncmount/mount_test.go

@@ -4,8 +4,8 @@ import (
 	"testing"
 
 	"github.com/ipfs/go-datastore"
-	"github.com/ipfs/go-datastore/mount"
 	"github.com/ipfs/go-datastore/query"
+	mount "github.com/ipfs/go-datastore/syncmount"
 )
 
 func TestPutBadNothing(t *testing.T) {
@@ -239,3 +239,40 @@ func TestQuerySimple(t *testing.T) {
 		t.Errorf("did not see wanted key %q in %+v", myKey, entries)
 	}
 }
+
+func TestLookupPrio(t *testing.T) {
+	mapds0 := datastore.NewMapDatastore()
+	mapds1 := datastore.NewMapDatastore()
+
+	m := mount.New([]mount.Mount{
+		{Prefix: datastore.NewKey("/"), Datastore: mapds0},
+		{Prefix: datastore.NewKey("/foo"), Datastore: mapds1},
+	})
+
+	m.Put(datastore.NewKey("/foo/bar"), "123")
+	m.Put(datastore.NewKey("/baz"), "234")
+
+	found, err := mapds0.Has(datastore.NewKey("/baz"))
+	if err != nil {
+		t.Fatalf("Has error: %v", err)
+	}
+	if g, e := found, true; g != e {
+		t.Fatalf("wrong value: %v != %v", g, e)
+	}
+
+	found, err = mapds0.Has(datastore.NewKey("/foo/bar"))
+	if err != nil {
+		t.Fatalf("Has error: %v", err)
+	}
+	if g, e := found, false; g != e {
+		t.Fatalf("wrong value: %v != %v", g, e)
+	}
+
+	found, err = mapds1.Has(datastore.NewKey("/bar"))
+	if err != nil {
+		t.Fatalf("Has error: %v", err)
+	}
+	if g, e := found, true; g != e {
+		t.Fatalf("wrong value: %v != %v", g, e)
+	}
+}