[#83] Allow to split objects in the client

Signed-off-by: Anton Nikiforov <an.nikiforov@yadro.com>

client/object_put_transformer.go

@@ -0,0 +1,88 @@
+package client
+
+import (
+	"context"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/transformer"
+)
+
+func (c *Client) objectPutInitTransformer(prm PrmObjectPutInit) (*objectWriterTransformer, error) {
+	var w objectWriterTransformer
+	w.it = internalTarget{
+		client: c,
+		prm:    prm,
+	}
+	key := &c.prm.key
+	if prm.key != nil {
+		key = prm.key
+	}
+	w.ot = transformer.NewPayloadSizeLimiter(transformer.Params{
+		Key:                    key,
+		NextTargetInit:         func() transformer.ObjectTarget { return &w.it },
+		MaxSize:                prm.maxSize,
+		WithoutHomomorphicHash: prm.withoutHomomorphicHash,
+		NetworkState:           prm.epochSource,
+	})
+	return &w, nil
+}
+
+type objectWriterTransformer struct {
+	ot  transformer.ObjectTarget
+	it  internalTarget
+	err error
+}
+
+func (x *objectWriterTransformer) WriteHeader(ctx context.Context, hdr object.Object) bool {
+	x.err = x.ot.WriteHeader(ctx, &hdr)
+	return x.err == nil
+}
+
+func (x *objectWriterTransformer) WritePayloadChunk(ctx context.Context, chunk []byte) bool {
+	_, x.err = x.ot.Write(ctx, chunk)
+	return x.err == nil
+}
+
+func (x *objectWriterTransformer) Close(ctx context.Context) (*ResObjectPut, error) {
+	if ai, err := x.ot.Close(ctx); err != nil {
+		return nil, err
+	} else {
+		if ai != nil && ai.ParentID != nil {
+			x.it.res.obj = *ai.ParentID
+		}
+		return x.it.res, nil
+	}
+}
+
+type internalTarget struct {
+	current *object.Object
+	client  *Client
+	res     *ResObjectPut
+	prm     PrmObjectPutInit
+	payload []byte
+}
+
+func (it *internalTarget) WriteHeader(_ context.Context, object *object.Object) error {
+	it.current = object
+	return nil
+}
+
+func (it *internalTarget) Write(_ context.Context, p []byte) (n int, err error) {
+	it.payload = append(it.payload, p...)
+	return len(p), nil
+}
+
+func (it *internalTarget) Close(ctx context.Context) (*transformer.AccessIdentifiers, error) {
+	it.current.SetPayload(it.payload)
+	wrt, err := it.client.objectPutInitRaw(ctx, it.prm)
+	if err != nil {
+		return nil, err
+	}
+	if wrt.WriteHeader(ctx, *it.current) {
+		wrt.WritePayloadChunk(ctx, it.current.Payload())
+	}
+	it.res, err = wrt.Close(ctx)
+	it.current = nil
+	it.payload = nil
+	return nil, err
+}