repository: move backend.LoadAll to repository.LoadRaw

LoadRaw also includes improved context cancellation handling similar to the
implementation in repository.LoadUnpacked.

The removed cache backend test will be added again later on.

internal/repository/raw_test.go

@@ -0,0 +1,91 @@
+package repository_test
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"math/rand"
+	"testing"
+
+	"github.com/restic/restic/internal/backend"
+	"github.com/restic/restic/internal/backend/mem"
+	"github.com/restic/restic/internal/backend/mock"
+	"github.com/restic/restic/internal/errors"
+	"github.com/restic/restic/internal/repository"
+	"github.com/restic/restic/internal/restic"
+	rtest "github.com/restic/restic/internal/test"
+)
+
+const KiB = 1 << 10
+const MiB = 1 << 20
+
+func TestLoadAll(t *testing.T) {
+	b := mem.New()
+	repo, err := repository.New(b, repository.Options{})
+	rtest.OK(t, err)
+
+	for i := 0; i < 5; i++ {
+		data := rtest.Random(23+i, rand.Intn(MiB)+500*KiB)
+
+		id := restic.Hash(data)
+		h := backend.Handle{Name: id.String(), Type: backend.PackFile}
+		err := b.Save(context.TODO(), h, backend.NewByteReader(data, b.Hasher()))
+		rtest.OK(t, err)
+
+		buf, err := repo.LoadRaw(context.TODO(), backend.PackFile, id)
+		rtest.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
+		}
+	}
+}
+
+type quickRetryBackend struct {
+	backend.Backend
+}
+
+func (be *quickRetryBackend) Load(ctx context.Context, h backend.Handle, length int, offset int64, fn func(rd io.Reader) error) error {
+	err := be.Backend.Load(ctx, h, length, offset, fn)
+	if err != nil {
+		// retry
+		err = be.Backend.Load(ctx, h, length, offset, fn)
+	}
+	return err
+}
+
+func TestLoadAllBroken(t *testing.T) {
+	b := mock.NewBackend()
+	repo, err := repository.New(b, repository.Options{})
+	rtest.OK(t, err)
+
+	data := rtest.Random(23, rand.Intn(MiB)+500*KiB)
+	id := restic.Hash(data)
+	// damage buffer
+	data[0] ^= 0xff
+
+	b.OpenReaderFn = func(ctx context.Context, h backend.Handle, length int, offset int64) (io.ReadCloser, error) {
+		return io.NopCloser(bytes.NewReader(data)), nil
+	}
+
+	// must fail on first try
+	_, err = repo.LoadRaw(context.TODO(), backend.PackFile, id)
+	rtest.Assert(t, errors.Is(err, restic.ErrInvalidData), "missing expected ErrInvalidData error, got %v", err)
+
+	// must return the broken data after a retry
+	be := &quickRetryBackend{Backend: b}
+	repo, err = repository.New(be, repository.Options{})
+	rtest.OK(t, err)
+	buf, err := repo.LoadRaw(context.TODO(), backend.PackFile, id)
+	rtest.Assert(t, errors.Is(err, restic.ErrInvalidData), "missing expected ErrInvalidData error, got %v", err)
+
+	if !bytes.Equal(buf, data) {
+		t.Fatalf("wrong data returned")
+	}
+}