[#1310] object: Move target initialization to separate package

* Split the logic of write target initialization to different packages;
* Refactor patch and put services: since both service initialize the target
  themselves.

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

pkg/services/object/common/writer/common.go

@@ -0,0 +1,118 @@
+package writer
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"sync/atomic"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
+	svcutil "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object/util"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/services/object_manager/placement"
+	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	"go.uber.org/zap"
+)
+
+type NodeIterator struct {
+	Traversal
+	cfg *Config
+}
+
+func (c *Config) NewNodeIterator(opts []placement.Option) *NodeIterator {
+	return &NodeIterator{
+		Traversal: Traversal{
+			Opts:    opts,
+			Exclude: make(map[string]*bool),
+		},
+		cfg: c,
+	}
+}
+
+func (n *NodeIterator) ForEachNode(ctx context.Context, f func(context.Context, NodeDescriptor) error) error {
+	traverser, err := placement.NewTraverser(n.Traversal.Opts...)
+	if err != nil {
+		return fmt.Errorf("could not create object placement traverser: %w", err)
+	}
+
+	resErr := &atomic.Value{}
+
+	// Must iterate over all replicas, regardless of whether there are identical nodes there.
+	// At the same time need to exclude identical nodes from processing.
+	for {
+		addrs := traverser.Next()
+		if len(addrs) == 0 {
+			break
+		}
+
+		if n.forEachAddress(ctx, traverser, addrs, f, resErr) {
+			break
+		}
+	}
+
+	if !traverser.Success() {
+		var err errIncompletePut
+		err.singleErr, _ = resErr.Load().(error)
+		return err
+	}
+
+	// perform additional container broadcast if needed
+	if n.Traversal.submitPrimaryPlacementFinish() {
+		err := n.ForEachNode(ctx, f)
+		if err != nil {
+			n.cfg.Logger.Error(logs.PutAdditionalContainerBroadcastFailure, zap.Error(err))
+			// we don't fail primary operation because of broadcast failure
+		}
+	}
+
+	return nil
+}
+
+func (n *NodeIterator) forEachAddress(ctx context.Context, traverser *placement.Traverser, addrs []placement.Node, f func(context.Context, NodeDescriptor) error, resErr *atomic.Value) bool {
+	var wg sync.WaitGroup
+
+	for _, addr := range addrs {
+		if ok := n.Exclude[string(addr.PublicKey())]; ok != nil {
+			if *ok {
+				traverser.SubmitSuccess()
+			}
+			// This can happen only during additional container broadcast.
+			continue
+		}
+
+		workerPool, isLocal := n.cfg.getWorkerPool(addr.PublicKey())
+
+		item := new(bool)
+		wg.Add(1)
+		if err := workerPool.Submit(func() {
+			defer wg.Done()
+
+			err := f(ctx, NodeDescriptor{Local: isLocal, Info: addr})
+			if err != nil {
+				resErr.Store(err)
+				svcutil.LogServiceError(n.cfg.Logger, "PUT", addr.Addresses(), err)
+				return
+			}
+
+			traverser.SubmitSuccess()
+			*item = true
+		}); err != nil {
+			wg.Done()
+			svcutil.LogWorkerPoolError(n.cfg.Logger, "PUT", err)
+			return true
+		}
+
+		// Mark the container node as processed in order to exclude it
+		// in subsequent container broadcast. Note that we don't
+		// process this node during broadcast if primary placement
+		// on it failed.
+		n.Traversal.submitProcessed(addr, item)
+	}
+
+	wg.Wait()
+
+	return false
+}
+
+func NeedAdditionalBroadcast(obj *objectSDK.Object, localOnly bool) bool {
+	return len(obj.Children()) > 0 || (!localOnly && (obj.Type() == objectSDK.TypeTombstone || obj.Type() == objectSDK.TypeLock))
+}