Add LoadAll()

backend/utils.go

@@ -0,0 +1,18 @@
+package backend
+
+// LoadAll reads all data stored in the backend for the handle. The buffer buf
+// is resized to accomodate all data in the blob.
+func LoadAll(be Backend, h Handle, buf []byte) ([]byte, error) {
+	fi, err := be.Stat(h)
+	if err != nil {
+		return nil, err
+	}
+
+	if fi.Size > int64(len(buf)) {
+		buf = make([]byte, int(fi.Size))
+	}
+
+	n, err := be.Load(h, buf, 0)
+	buf = buf[:n]
+	return buf, err
+}

backend/utils_test.go

@@ -0,0 +1,44 @@
+package backend_test
+
+import (
+	"bytes"
+	"math/rand"
+	"testing"
+
+	"github.com/restic/restic/backend"
+	"github.com/restic/restic/backend/mem"
+	. "github.com/restic/restic/test"
+)
+
+const KiB = 1 << 10
+const MiB = 1 << 20
+
+func TestLoadAll(t *testing.T) {
+	b := mem.New()
+
+	for i := 0; i < 20; i++ {
+		data := Random(23+i, rand.Intn(MiB)+500*KiB)
+
+		id := backend.Hash(data)
+
+		blob, err := b.Create()
+		OK(t, err)
+
+		_, err = blob.Write([]byte(data))
+		OK(t, err)
+		OK(t, blob.Finalize(backend.Data, id.String()))
+
+		buf, err := backend.LoadAll(b, backend.Handle{Type: backend.Data, Name: id.String()}, nil)
+		OK(t, err)
+
+		if len(buf) != len(data) {
+			t.Errorf("length of returned buffer does not match, want %d, got %d", len(data), len(buf))
+			continue
+		}
+
+		if !bytes.Equal(buf, data) {
+			t.Errorf("wrong data returned")
+			continue
+		}
+	}
+}