[#248] client: Introduce object patcher

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

client/object_patch.go

@@ -0,0 +1,249 @@
+package client
+
+import (
+	"context"
+	"crypto/ecdsa"
+	"errors"
+	"fmt"
+	"io"
+
+	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/acl"
+	v2object "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/object"
+	rpcapi "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/rpc"
+	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/rpc/client"
+	v2session "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/session"
+	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/signature"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/bearer"
+	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
+	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/session"
+)
+
+// ObjectPatcher is designed to patch an object.
+//
+// Must be initialized using Client.ObjectPatchInit, any other
+// usage is unsafe.
+type ObjectPatcher interface {
+	// Patch patches the object.
+	//
+	// If object.Patch parameter sets `NewAttributes`, `ReplaceAttributes` or both fields, then the
+	// request is taken for patching the object's attributes. Attributes can be patched no more than once,
+	// otherwise, the server returns an error.
+	//
+	// If object.Patch parameter sets `PayloadPatch` with a large `Chunk`, then this patch is splitted
+	// into a few patches. After split each `PayloadPatch` has a `Chunk` with the size <= `MaxChunkLength`.
+	//
+	// Result means success. Failure reason can be received via Close.
+	Patch(_ context.Context, patch *object.Patch) bool
+	// Close ends patching the object and returns the result of the operation
+	// along with the final results. Must be called after using the ObjectPatcher.
+	//
+	// Exactly one return value is non-nil. By default, server status is returned in res structure.
+	// Any client's internal or transport errors are returned as Go built-in error.
+	// If Client is tuned to resolve FrostFS API statuses, then FrostFS failures
+	// codes are returned as error.
+	//
+	// Return statuses:
+	//   - global (see Client docs);
+	//   - *apistatus.ContainerNotFound;
+	//   - *apistatus.ContainerAccessDenied;
+	//   - *apistatus.ObjectAccessDenied;
+	//   - *apistatus.ObjectAlreadyRemoved;
+	//   - *apistatus.ObjectLocked;
+	//   - *apistatus.ObjectOutOfRange;
+	//   - *apistatus.SessionTokenNotFound;
+	//   - *apistatus.SessionTokenExpired.
+	Close(_ context.Context) (*ResObjectPatch, error)
+}
+
+// ResObjectPatch groups resulting values of ObjectPatch operation.
+type ResObjectPatch struct {
+	statusRes
+
+	obj oid.ID
+}
+
+// ObjectID returns an object ID of the patched object.
+func (r ResObjectPatch) ObjectID() oid.ID {
+	return r.obj
+}
+
+// PrmObjectPatch groups parameters of ObjectPatch operation.
+type PrmObjectPatch struct {
+	XHeaders []string
+
+	BearerToken *bearer.Token
+
+	Session *session.Object
+
+	Local bool
+
+	Address oid.Address
+
+	Key *ecdsa.PrivateKey
+
+	MaxChunkLength int
+}
+
+// ObjectPatchInit initializes object patcher.
+func (c *Client) ObjectPatchInit(ctx context.Context, prm PrmObjectPatch) (ObjectPatcher, error) {
+	if len(prm.XHeaders)%2 != 0 {
+		return nil, errorInvalidXHeaders
+	}
+
+	var objectPatcher objectPatcher
+	stream, err := rpcapi.Patch(&c.c, &objectPatcher.respV2, client.WithContext(ctx))
+	if err != nil {
+		return nil, fmt.Errorf("open stream: %w", err)
+	}
+
+	objectPatcher.key = &c.prm.Key
+	if prm.Key != nil {
+		objectPatcher.key = prm.Key
+	}
+	objectPatcher.client = c
+	objectPatcher.stream = stream
+	objectPatcher.addr = prm.Address
+
+	if prm.MaxChunkLength > 0 {
+		objectPatcher.maxChunkLen = prm.MaxChunkLength
+	} else {
+		objectPatcher.maxChunkLen = defaultGRPCPayloadChunkLen
+	}
+
+	objectPatcher.req.SetBody(&v2object.PatchRequestBody{})
+
+	meta := new(v2session.RequestMetaHeader)
+	writeXHeadersToMeta(prm.XHeaders, meta)
+
+	if prm.BearerToken != nil {
+		v2BearerToken := new(acl.BearerToken)
+		prm.BearerToken.WriteToV2(v2BearerToken)
+		meta.SetBearerToken(v2BearerToken)
+	}
+
+	if prm.Session != nil {
+		v2SessionToken := new(v2session.Token)
+		prm.Session.WriteToV2(v2SessionToken)
+		meta.SetSessionToken(v2SessionToken)
+	}
+
+	if prm.Local {
+		meta.SetTTL(1)
+	}
+
+	c.prepareRequest(&objectPatcher.req, meta)
+
+	return &objectPatcher, nil
+}
+
+type objectPatcher struct {
+	client *Client
+
+	stream interface {
+		Write(*v2object.PatchRequest) error
+		Close() error
+	}
+
+	key *ecdsa.PrivateKey
+	res ResObjectPatch
+	err error
+
+	addr oid.Address
+
+	req    v2object.PatchRequest
+	respV2 v2object.PatchResponse
+
+	maxChunkLen int
+}
+
+func (x *objectPatcher) Patch(_ context.Context, patch *object.Patch) bool {
+	if patch == nil {
+		x.err = errors.New("nil patch")
+		return false
+	}
+
+	patches := []*object.Patch{patch}
+	if patch.PayloadPatch != nil && len(patch.PayloadPatch.Chunk) > x.maxChunkLen {
+		patches = x.splitPatch(patch)
+	}
+
+	for _, p := range patches {
+		if !x.send(p) {
+			return false
+		}
+	}
+
+	return true
+}
+
+// splitPatch splits Patch into a few ones if the original Patch has a large PayloadPatch that is required to be splitted.
+func (x *objectPatcher) splitPatch(patch *object.Patch) []*object.Patch {
+	payloadPatches := patch.PayloadPatch.SplitByMaxChunkLength(x.maxChunkLen)
+	result := make([]*object.Patch, len(payloadPatches))
+
+	for i, pp := range payloadPatches {
+		newPatch := &object.Patch{
+			Address:      patch.Address,
+			PayloadPatch: pp,
+		}
+		if i == 0 {
+			newPatch.NewAttributes = patch.NewAttributes
+			newPatch.ReplaceAttributes = patch.ReplaceAttributes
+		}
+		result[i] = newPatch
+	}
+
+	return result
+}
+
+func (x *objectPatcher) send(patch *object.Patch) bool {
+	x.req.SetBody(patch.ToV2())
+	x.req.SetVerificationHeader(nil)
+
+	x.err = signature.SignServiceMessage(x.key, &x.req)
+	if x.err != nil {
+		x.err = fmt.Errorf("sign message: %w", x.err)
+		return false
+	}
+
+	x.err = x.stream.Write(&x.req)
+	return x.err == nil
+}
+
+func (x *objectPatcher) Close(_ context.Context) (*ResObjectPatch, error) {
+	// Ignore io.EOF error, because it is expected error for client-side
+	// stream termination by the server. E.g. when stream contains invalid
+	// message. Server returns an error in response message (in status).
+	if x.err != nil && !errors.Is(x.err, io.EOF) {
+		return nil, x.err
+	}
+
+	if x.err = x.stream.Close(); x.err != nil {
+		return nil, x.err
+	}
+
+	x.res.st, x.err = x.client.processResponse(&x.respV2)
+	if x.err != nil {
+		return nil, x.err
+	}
+
+	if !apistatus.IsSuccessful(x.res.st) {
+		return &x.res, nil
+	}
+
+	const fieldID = "ID"
+
+	idV2 := x.respV2.Body.ObjectID
+	if idV2 == nil {
+		return nil, newErrMissingResponseField(fieldID)
+	}
+
+	x.err = x.res.obj.ReadFromV2(*idV2)
+	if x.err != nil {
+		x.err = newErrInvalidResponseField(fieldID, x.err)
+	}
+
+	return &x.res, nil
+}