From c02c7bee5b11dd020e36ce2ec1808e1d1ea889fe Mon Sep 17 00:00:00 2001
From: Alex Vanin <alexey@nspcc.ru>
Date: Wed, 27 Oct 2021 17:51:58 +0300
Subject: [PATCH] [#948] engine: Add ListWithCursor method

Interface for shard.ListWithCursor invocations.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>
---
 pkg/local_object_storage/engine/list.go      | 74 ++++++++++++++++++++
 pkg/local_object_storage/engine/list_test.go | 60 ++++++++++++++++
 2 files changed, 134 insertions(+)
 create mode 100644 pkg/local_object_storage/engine/list.go
 create mode 100644 pkg/local_object_storage/engine/list_test.go

diff --git a/pkg/local_object_storage/engine/list.go b/pkg/local_object_storage/engine/list.go
new file mode 100644
index 000000000..64e1e3540
--- /dev/null
+++ b/pkg/local_object_storage/engine/list.go
@@ -0,0 +1,74 @@
+package engine
+
+import (
+	"github.com/nspcc-dev/neofs-api-go/pkg/object"
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/shard"
+)
+
+// ListWithCursorPrm contains parameters for ListWithCursor operation.
+type ListWithCursorPrm struct {
+	count  uint32
+	cursor string
+	shard  shard.ID
+}
+
+// WithCount sets maximum amount of addresses that ListWithCursor can return.
+func (p *ListWithCursorPrm) WithCount(count uint32) *ListWithCursorPrm {
+	p.count = count
+	return p
+}
+
+// WithCursor sets cursor for ListWithCursor operation. For initial request
+// ignore this param or use empty string. For continues requests, use  value
+// from ListWithCursorRes.
+func (p *ListWithCursorPrm) WithCursor(cursor string) *ListWithCursorPrm {
+	p.cursor = cursor
+	return p
+}
+
+// WithShardID sets shard where listing will process.
+func (p *ListWithCursorPrm) WithShardID(id shard.ID) *ListWithCursorPrm {
+	p.shard = id
+	return p
+}
+
+// ListWithCursorRes contains values returned from ListWithCursor operation.
+type ListWithCursorRes struct {
+	addrList []*object.Address
+	cursor   string
+}
+
+// AddressList returns addresses selected by ListWithCursor operation.
+func (l ListWithCursorRes) AddressList() []*object.Address {
+	return l.addrList
+}
+
+// Cursor returns cursor for consecutive listing requests.
+func (l ListWithCursorRes) Cursor() string {
+	return l.cursor
+}
+
+// ListWithCursor lists physical objects available in specified shard starting
+// from cursor. Includes regular,tombstone and storage group objects.
+// Does not include inhumed objects. Use cursor value from response
+// for consecutive requests.
+func (e *StorageEngine) ListWithCursor(prm *ListWithCursorPrm) (*ListWithCursorRes, error) {
+	e.mtx.RLock()
+	shardInstance, ok := e.shards[prm.shard.String()]
+	e.mtx.RUnlock()
+
+	if !ok {
+		return nil, errShardNotFound
+	}
+
+	shardPrm := new(shard.ListWithCursorPrm).WithCursor(prm.cursor).WithCount(prm.count)
+	res, err := shardInstance.ListWithCursor(shardPrm)
+	if err != nil {
+		return nil, err
+	}
+
+	return &ListWithCursorRes{
+		addrList: res.AddressList(),
+		cursor:   res.Cursor(),
+	}, nil
+}
diff --git a/pkg/local_object_storage/engine/list_test.go b/pkg/local_object_storage/engine/list_test.go
new file mode 100644
index 000000000..edaf852eb
--- /dev/null
+++ b/pkg/local_object_storage/engine/list_test.go
@@ -0,0 +1,60 @@
+package engine
+
+import (
+	"os"
+	"sort"
+	"testing"
+
+	cidtest "github.com/nspcc-dev/neofs-api-go/pkg/container/id/test"
+	"github.com/nspcc-dev/neofs-api-go/pkg/object"
+	meta "github.com/nspcc-dev/neofs-node/pkg/local_object_storage/metabase"
+	"github.com/stretchr/testify/require"
+)
+
+func TestListWithCursor(t *testing.T) {
+	s1 := testNewShard(t, 1)
+	s2 := testNewShard(t, 2)
+	e := testNewEngineWithShards(s1, s2)
+
+	t.Cleanup(func() {
+		e.Close()
+		os.RemoveAll(t.Name())
+	})
+
+	const total = 20
+
+	expected := make([]*object.Address, 0, total)
+	got := make([]*object.Address, 0, total)
+
+	for i := 0; i < total; i++ {
+		containerID := cidtest.Generate()
+		obj := generateRawObjectWithCID(t, containerID)
+		prm := new(PutPrm).WithObject(obj.Object())
+		_, err := e.Put(prm)
+		require.NoError(t, err)
+		expected = append(expected, obj.Object().Address())
+	}
+
+	expected = sortAddresses(expected)
+
+	for _, shard := range e.DumpInfo().Shards {
+		prm := new(ListWithCursorPrm).WithShardID(*shard.ID).WithCount(total)
+		res, err := e.ListWithCursor(prm)
+		require.NoError(t, err)
+		require.NotEmpty(t, res.AddressList())
+
+		got = append(got, res.AddressList()...)
+		_, err = e.ListWithCursor(prm.WithCursor(res.Cursor()))
+		require.ErrorIs(t, err, meta.ErrEndOfListing)
+	}
+
+	got = sortAddresses(got)
+	require.Equal(t, expected, got)
+}
+
+func sortAddresses(addr []*object.Address) []*object.Address {
+	sort.Slice(addr, func(i, j int) bool {
+		return addr[i].String() < addr[j].String()
+	})
+	return addr
+}