Golang sha256.New函數代碼示例

// sum256Reader calculate sha256 sum for an input read seeker
func sum256Reader(reader io.ReadSeeker) ([]byte, error) {
	h := sha256.New()
	var err error

	start, _ := reader.Seek(0, 1)
	defer reader.Seek(start, 0)

	for err == nil {
		length := 0
		byteBuffer := make([]byte, 1024*1024)
		length, err = reader.Read(byteBuffer)
		byteBuffer = byteBuffer[0:length]
		h.Write(byteBuffer)
	}

	if err != io.EOF {
		return nil, err
	}

	return h.Sum(nil), nil
}

// createObject - internal wrapper function called by CreateObjectPart
func (donut API) createObjectPart(bucket, key, uploadID string, partID int, contentType, expectedMD5Sum string, size int64, data io.Reader, signature *Signature) (string, error) {
	if !IsValidBucket(bucket) {
		return "", iodine.New(BucketNameInvalid{Bucket: bucket}, nil)
	}
	if !IsValidObjectName(key) {
		return "", iodine.New(ObjectNameInvalid{Object: key}, nil)
	}
	if !donut.storedBuckets.Exists(bucket) {
		return "", iodine.New(BucketNotFound{Bucket: bucket}, nil)
	}
	storedBucket := donut.storedBuckets.Get(bucket).(storedBucket)
	// Verify upload id
	if storedBucket.multiPartSession[key].uploadID != uploadID {
		return "", iodine.New(InvalidUploadID{UploadID: uploadID}, nil)
	}

	// get object key
	if _, ok := storedBucket.partMetadata[partID]; ok {
		return storedBucket.partMetadata[partID].ETag, nil
	}

	if contentType == "" {
		contentType = "application/octet-stream"
	}
	contentType = strings.TrimSpace(contentType)
	if strings.TrimSpace(expectedMD5Sum) != "" {
		expectedMD5SumBytes, err := base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// pro-actively close the connection
			return "", iodine.New(InvalidDigest{Md5: expectedMD5Sum}, nil)
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	// calculate md5
	hash := md5.New()
	sha256hash := sha256.New()

	var err error
	var totalLength int64
	for err == nil {
		var length int
		byteBuffer := make([]byte, 1024*1024)
		length, err = data.Read(byteBuffer)
		hash.Write(byteBuffer[0:length])
		sha256hash.Write(byteBuffer[0:length])
		ok := donut.multiPartObjects[uploadID].Append(partID, byteBuffer[0:length])
		if !ok {
			return "", iodine.New(InternalError{}, nil)
		}
		totalLength += int64(length)
		go debug.FreeOSMemory()
	}
	if totalLength != size {
		donut.multiPartObjects[uploadID].Delete(partID)
		return "", iodine.New(IncompleteBody{Bucket: bucket, Object: key}, nil)
	}
	if err != io.EOF {
		return "", iodine.New(err, nil)
	}

	md5SumBytes := hash.Sum(nil)
	md5Sum := hex.EncodeToString(md5SumBytes)
	// Verify if the written object is equal to what is expected, only if it is requested as such
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if err := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum); err != nil {
			return "", iodine.New(BadDigest{}, nil)
		}
	}

	if signature != nil {
		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sha256hash.Sum(nil)))
		if err != nil {
			return "", iodine.New(err, nil)
		}
		if !ok {
			return "", iodine.New(SignatureDoesNotMatch{}, nil)
		}
	}

	newPart := PartMetadata{
		PartNumber:   partID,
		LastModified: time.Now().UTC(),
		ETag:         md5Sum,
		Size:         totalLength,
	}

	storedBucket.partMetadata[partID] = newPart
	multiPartSession := storedBucket.multiPartSession[key]
	multiPartSession.totalParts++
	storedBucket.multiPartSession[key] = multiPartSession
	donut.storedBuckets.Set(bucket, storedBucket)
	return md5Sum, nil
}

// readObjectData -
func (b bucket) readObjectData(objectName string, writer *io.PipeWriter, objMetadata ObjectMetadata) {
	readers, err := b.getObjectReaders(objectName, "data")
	if err != nil {
		writer.CloseWithError(probe.WrapError(err))
		return
	}
	for _, reader := range readers {
		defer reader.Close()
	}
	var expected512Sum, expectedMd5sum []byte
	{
		var err error
		expectedMd5sum, err = hex.DecodeString(objMetadata.MD5Sum)
		if err != nil {
			writer.CloseWithError(probe.WrapError(probe.NewError(err)))
			return
		}
		expected512Sum, err = hex.DecodeString(objMetadata.SHA512Sum)
		if err != nil {
			writer.CloseWithError(probe.WrapError(probe.NewError(err)))
			return
		}
	}
	hasher := md5.New()
	sum512hasher := sha256.New()
	mwriter := io.MultiWriter(writer, hasher, sum512hasher)
	switch len(readers) > 1 {
	case true:
		if objMetadata.ErasureTechnique == "" {
			writer.CloseWithError(probe.WrapError(probe.NewError(MissingErasureTechnique{})))
			return
		}
		encoder, err := newEncoder(objMetadata.DataDisks, objMetadata.ParityDisks, objMetadata.ErasureTechnique)
		if err != nil {
			writer.CloseWithError(probe.WrapError(err))
			return
		}
		totalLeft := objMetadata.Size
		for i := 0; i < objMetadata.ChunkCount; i++ {
			decodedData, err := b.decodeEncodedData(totalLeft, int64(objMetadata.BlockSize), readers, encoder, writer)
			if err != nil {
				writer.CloseWithError(probe.WrapError(err))
				return
			}
			if _, err := io.Copy(mwriter, bytes.NewReader(decodedData)); err != nil {
				writer.CloseWithError(probe.WrapError(probe.NewError(err)))
				return
			}
			totalLeft = totalLeft - int64(objMetadata.BlockSize)
		}
	case false:
		_, err := io.Copy(writer, readers[0])
		if err != nil {
			writer.CloseWithError(probe.WrapError(probe.NewError(err)))
			return
		}
	}
	// check if decodedData md5sum matches
	if !bytes.Equal(expectedMd5sum, hasher.Sum(nil)) {
		writer.CloseWithError(probe.WrapError(probe.NewError(ChecksumMismatch{})))
		return
	}
	if !bytes.Equal(expected512Sum, sum512hasher.Sum(nil)) {
		writer.CloseWithError(probe.WrapError(probe.NewError(ChecksumMismatch{})))
		return
	}
	writer.Close()
	return
}

// WriteObject - write a new object into bucket
func (b bucket) WriteObject(objectName string, objectData io.Reader, size int64, expectedMD5Sum string, metadata map[string]string, signature *Signature) (ObjectMetadata, *probe.Error) {
	b.lock.Lock()
	defer b.lock.Unlock()
	if objectName == "" || objectData == nil {
		return ObjectMetadata{}, probe.NewError(InvalidArgument{})
	}
	writers, err := b.getObjectWriters(normalizeObjectName(objectName), "data")
	if err != nil {
		return ObjectMetadata{}, err.Trace()
	}
	sumMD5 := md5.New()
	sum512 := sha512.New()
	var sum256 hash.Hash
	var mwriter io.Writer

	if signature != nil {
		sum256 = sha256.New()
		mwriter = io.MultiWriter(sumMD5, sum256, sum512)
	} else {
		mwriter = io.MultiWriter(sumMD5, sum512)
	}
	objMetadata := ObjectMetadata{}
	objMetadata.Version = objectMetadataVersion
	objMetadata.Created = time.Now().UTC()
	// if total writers are only '1' do not compute erasure
	switch len(writers) == 1 {
	case true:
		mw := io.MultiWriter(writers[0], mwriter)
		totalLength, err := io.Copy(mw, objectData)
		if err != nil {
			CleanupWritersOnError(writers)
			return ObjectMetadata{}, probe.NewError(err)
		}
		objMetadata.Size = totalLength
	case false:
		// calculate data and parity dictated by total number of writers
		k, m, err := b.getDataAndParity(len(writers))
		if err != nil {
			CleanupWritersOnError(writers)
			return ObjectMetadata{}, err.Trace()
		}
		// write encoded data with k, m and writers
		chunkCount, totalLength, err := b.writeObjectData(k, m, writers, objectData, size, mwriter)
		if err != nil {
			CleanupWritersOnError(writers)
			return ObjectMetadata{}, err.Trace()
		}
		/// donutMetadata section
		objMetadata.BlockSize = blockSize
		objMetadata.ChunkCount = chunkCount
		objMetadata.DataDisks = k
		objMetadata.ParityDisks = m
		objMetadata.ErasureTechnique = "Cauchy"
		objMetadata.Size = int64(totalLength)
	}
	objMetadata.Bucket = b.getBucketName()
	objMetadata.Object = objectName
	dataMD5sum := sumMD5.Sum(nil)
	dataSHA512sum := sum512.Sum(nil)
	if signature != nil {
		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sum256.Sum(nil)))
		if err != nil {
			// error occurred while doing signature calculation, we return and also cleanup any temporary writers.
			CleanupWritersOnError(writers)
			return ObjectMetadata{}, err.Trace()
		}
		if !ok {
			// purge all writers, when control flow reaches here
			//
			// Signature mismatch occurred all temp files to be removed and all data purged.
			CleanupWritersOnError(writers)
			return ObjectMetadata{}, probe.NewError(SignatureDoesNotMatch{})
		}
	}
	objMetadata.MD5Sum = hex.EncodeToString(dataMD5sum)
	objMetadata.SHA512Sum = hex.EncodeToString(dataSHA512sum)

	// Verify if the written object is equal to what is expected, only if it is requested as such
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if err := b.isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), objMetadata.MD5Sum); err != nil {
			return ObjectMetadata{}, err.Trace()
		}
	}
	objMetadata.Metadata = metadata
	// write object specific metadata
	if err := b.writeObjectMetadata(normalizeObjectName(objectName), objMetadata); err != nil {
		// purge all writers, when control flow reaches here
		CleanupWritersOnError(writers)
		return ObjectMetadata{}, err.Trace()
	}
	// close all writers, when control flow reaches here
	for _, writer := range writers {
		writer.Close()
	}
	return objMetadata, nil
}

// createObject - PUT object to cache buffer
func (donut API) createObject(bucket, key, contentType, expectedMD5Sum string, size int64, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
	if len(donut.config.NodeDiskMap) == 0 {
		if size > int64(donut.config.MaxSize) {
			generic := GenericObjectError{Bucket: bucket, Object: key}
			return ObjectMetadata{}, probe.NewError(EntityTooLarge{
				GenericObjectError: generic,
				Size:               strconv.FormatInt(size, 10),
				MaxSize:            strconv.FormatUint(donut.config.MaxSize, 10),
			})
		}
	}
	if !IsValidBucket(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}
	if !IsValidObjectName(key) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Object: key})
	}
	if !donut.storedBuckets.Exists(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
	}
	storedBucket := donut.storedBuckets.Get(bucket).(storedBucket)
	// get object key
	objectKey := bucket + "/" + key
	if _, ok := storedBucket.objectMetadata[objectKey]; ok == true {
		return ObjectMetadata{}, probe.NewError(ObjectExists{Object: key})
	}

	if contentType == "" {
		contentType = "application/octet-stream"
	}
	contentType = strings.TrimSpace(contentType)
	if strings.TrimSpace(expectedMD5Sum) != "" {
		expectedMD5SumBytes, err := base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// pro-actively close the connection
			return ObjectMetadata{}, probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	if len(donut.config.NodeDiskMap) > 0 {
		objMetadata, err := donut.putObject(
			bucket,
			key,
			expectedMD5Sum,
			data,
			size,
			map[string]string{
				"contentType":   contentType,
				"contentLength": strconv.FormatInt(size, 10),
			},
			signature,
		)
		if err != nil {
			return ObjectMetadata{}, err.Trace()
		}
		storedBucket.objectMetadata[objectKey] = objMetadata
		donut.storedBuckets.Set(bucket, storedBucket)
		return objMetadata, nil
	}
	// calculate md5
	hash := md5.New()
	sha256hash := sha256.New()

	var err error
	var totalLength int64
	for err == nil {
		var length int
		byteBuffer := make([]byte, 1024*1024)
		length, err = data.Read(byteBuffer)
		hash.Write(byteBuffer[0:length])
		sha256hash.Write(byteBuffer[0:length])
		ok := donut.objects.Append(objectKey, byteBuffer[0:length])
		if !ok {
			return ObjectMetadata{}, probe.NewError(InternalError{})
		}
		totalLength += int64(length)
		go debug.FreeOSMemory()
	}
	if totalLength != size {
		// Delete perhaps the object is already saved, due to the nature of append()
		donut.objects.Delete(objectKey)
		return ObjectMetadata{}, probe.NewError(IncompleteBody{Bucket: bucket, Object: key})
	}
	if err != io.EOF {
		return ObjectMetadata{}, probe.NewError(err)
	}
	md5SumBytes := hash.Sum(nil)
	md5Sum := hex.EncodeToString(md5SumBytes)
	// Verify if the written object is equal to what is expected, only if it is requested as such
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if err := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum); err != nil {
			return ObjectMetadata{}, probe.NewError(BadDigest{})
		}
	}
	if signature != nil {
		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sha256hash.Sum(nil)))
		if err != nil {
			return ObjectMetadata{}, err.Trace()
//.........這裏部分代碼省略.........

// PutBucketHandler - PUT Bucket
// ----------
// This implementation of the PUT operation creates a new bucket for authenticated request
func (api storageAPI) PutBucketHandler(w http.ResponseWriter, r *http.Request) {
	vars := mux.Vars(r)
	bucket := vars["bucket"]

	if isRequestRequiresACLCheck(r) {
		writeErrorResponse(w, r, AccessDenied, r.URL.Path)
		return
	}

	// read from 'x-amz-acl'
	aclType := getACLType(r)
	if aclType == unsupportedACLType {
		writeErrorResponse(w, r, NotImplemented, r.URL.Path)
		return
	}

	// if body of request is non-nil then check for validity of Content-Length
	if r.Body != nil {
		/// if Content-Length is unknown/missing, deny the request
		if r.ContentLength == -1 && !contains(r.TransferEncoding, "chunked") {
			writeErrorResponse(w, r, MissingContentLength, r.URL.Path)
			return
		}
	}

	// Set http request for signature.
	auth := api.Signature.SetHTTPRequestToVerify(r)
	if isRequestPresignedSignatureV4(r) {
		ok, err := auth.DoesPresignedSignatureMatch()
		if err != nil {
			errorIf(err.Trace(r.URL.String()), "Presigned signature verification failed.", nil)
			writeErrorResponse(w, r, SignatureDoesNotMatch, r.URL.Path)
			return
		}
		if !ok {
			writeErrorResponse(w, r, SignatureDoesNotMatch, r.URL.Path)
			return
		}
	} else if isRequestSignatureV4(r) {
		// Verify signature for the incoming body if any.
		locationBytes, e := ioutil.ReadAll(r.Body)
		if e != nil {
			errorIf(probe.NewError(e), "MakeBucket failed.", nil)
			writeErrorResponse(w, r, InternalError, r.URL.Path)
			return
		}
		sh := sha256.New()
		sh.Write(locationBytes)
		ok, err := auth.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
		if err != nil {
			errorIf(err.Trace(), "MakeBucket failed.", nil)
			writeErrorResponse(w, r, InternalError, r.URL.Path)
			return
		}
		if !ok {
			writeErrorResponse(w, r, SignatureDoesNotMatch, r.URL.Path)
			return
		}
	}

	// Make bucket.
	err := api.Filesystem.MakeBucket(bucket, getACLTypeString(aclType))
	if err != nil {
		errorIf(err.Trace(), "MakeBucket failed.", nil)
		switch err.ToGoError().(type) {
		case fs.BucketNameInvalid:
			writeErrorResponse(w, r, InvalidBucketName, r.URL.Path)
		case fs.BucketExists:
			writeErrorResponse(w, r, BucketAlreadyExists, r.URL.Path)
		default:
			writeErrorResponse(w, r, InternalError, r.URL.Path)
		}
		return
	}
	// Make sure to add Location information here only for bucket
	w.Header().Set("Location", "/"+bucket)
	writeSuccessResponse(w, nil)
}

// CreateObject - create an object.
func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size int64, data io.Reader, signature *signV4.Signature) (ObjectMetadata, *probe.Error) {
	di, e := disk.GetInfo(fs.path)
	if e != nil {
		return ObjectMetadata{}, probe.NewError(e)
	}

	// Remove 5% from total space for cumulative disk space used for
	// journalling, inodes etc.
	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
	if int64(availableDiskSpace) <= fs.minFreeDisk {
		return ObjectMetadata{}, probe.NewError(RootPathFull{Path: fs.path})
	}

	// Check bucket name valid.
	if !IsValidBucketName(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, e = os.Stat(bucketPath); e != nil {
		if os.IsNotExist(e) {
			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return ObjectMetadata{}, probe.NewError(e)
	}

	// Verify object path legal.
	if !IsValidObjectName(object) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	// Get object path.
	objectPath := filepath.Join(bucketPath, object)
	if strings.TrimSpace(expectedMD5Sum) != "" {
		var expectedMD5SumBytes []byte
		expectedMD5SumBytes, e = base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if e != nil {
			// Pro-actively close the connection.
			return ObjectMetadata{}, probe.NewError(InvalidDigest{MD5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	// Write object.
	file, e := atomic.FileCreateWithPrefix(objectPath, "$tmpobject")
	if e != nil {
		switch e := e.(type) {
		case *os.PathError:
			if e.Op == "mkdir" {
				if strings.Contains(e.Error(), "not a directory") {
					return ObjectMetadata{}, probe.NewError(ObjectExistsAsPrefix{Bucket: bucket, Prefix: object})
				}
			}
			return ObjectMetadata{}, probe.NewError(e)
		default:
			return ObjectMetadata{}, probe.NewError(e)
		}
	}

	// Instantiate checksum hashers and create a multiwriter.
	md5Hasher := md5.New()
	sha256Hasher := sha256.New()
	objectWriter := io.MultiWriter(file, md5Hasher, sha256Hasher)

	if size > 0 {
		if _, e = io.CopyN(objectWriter, data, size); e != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(e)
		}
	} else {
		if _, e = io.Copy(objectWriter, data); e != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(e)
		}
	}

	md5Sum := hex.EncodeToString(md5Hasher.Sum(nil))
	// Verify if the written object is equal to what is expected, only
	// if it is requested as such.
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if !isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum) {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(BadDigest{MD5: expectedMD5Sum, Bucket: bucket, Object: object})
		}
	}
	sha256Sum := hex.EncodeToString(sha256Hasher.Sum(nil))
	if signature != nil {
		ok, err := signature.DoesSignatureMatch(sha256Sum)
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, err.Trace()
		}
		if !ok {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(signV4.SigDoesNotMatch{})
		}
	}
	file.Close()
//.........這裏部分代碼省略.........

// CompleteMultipartUpload - complete a multipart upload and persist the data
func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, data io.Reader, signature *signV4.Signature) (ObjectMetadata, *probe.Error) {
	// Check bucket name is valid.
	if !IsValidBucketName(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	// Verify object path is legal.
	if !IsValidObjectName(object) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	// Verify if valid upload for incoming object.
	if !fs.isValidUploadID(object, uploadID) {
		return ObjectMetadata{}, probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, e := os.Stat(bucketPath); e != nil {
		// Check bucket exists.
		if os.IsNotExist(e) {
			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return ObjectMetadata{}, probe.NewError(InternalError{})
	}

	objectPath := filepath.Join(bucketPath, object)
	file, e := atomic.FileCreateWithPrefix(objectPath, "$tmpobject")
	if e != nil {
		return ObjectMetadata{}, probe.NewError(e)
	}
	md5Hasher := md5.New()
	objectWriter := io.MultiWriter(file, md5Hasher)

	partBytes, e := ioutil.ReadAll(data)
	if e != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(e)
	}
	if signature != nil {
		sh := sha256.New()
		sh.Write(partBytes)
		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, err.Trace()
		}
		if !ok {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(signV4.SigDoesNotMatch{})
		}
	}
	completeMultipartUpload := &CompleteMultipartUpload{}
	if e := xml.Unmarshal(partBytes, completeMultipartUpload); e != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(MalformedXML{})
	}
	if !sort.IsSorted(completedParts(completeMultipartUpload.Part)) {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(InvalidPartOrder{})
	}

	// Save parts for verification.
	parts := completeMultipartUpload.Part

	// Critical region requiring read lock.
	fs.rwLock.RLock()
	savedParts := fs.multiparts.ActiveSession[uploadID].Parts
	fs.rwLock.RUnlock()

	if !doPartsMatch(parts, savedParts) {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(InvalidPart{})
	}

	// Parts successfully validated, save all the parts.
	partPathPrefix := objectPath + uploadID
	if err := saveParts(partPathPrefix, objectWriter, parts); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, err.Trace(partPathPrefix)
	}
	// Successfully saved, remove all parts.
	removeParts(partPathPrefix, savedParts)

	// Critical region requiring write lock.
	fs.rwLock.Lock()
	delete(fs.multiparts.ActiveSession, uploadID)
	if err := saveMultipartsSession(*fs.multiparts); err != nil {
		fs.rwLock.Unlock()
		file.CloseAndPurge()
		return ObjectMetadata{}, err.Trace(partPathPrefix)
	}
	file.Close()
	fs.rwLock.Unlock()

	// Send stat again to get object metadata.
	st, e := os.Stat(objectPath)
	if e != nil {
		return ObjectMetadata{}, probe.NewError(e)
//.........這裏部分代碼省略.........

// CreateObjectPart - create a part in a multipart session
func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum string, partID int, size int64, data io.Reader, signature *signV4.Signature) (string, *probe.Error) {
	di, err := disk.GetInfo(fs.path)
	if err != nil {
		return "", probe.NewError(err)
	}

	// Remove 5% from total space for cumulative disk space used for
	// journalling, inodes etc.
	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
	if int64(availableDiskSpace) <= fs.minFreeDisk {
		return "", probe.NewError(RootPathFull{Path: fs.path})
	}

	// Part id cannot be negative.
	if partID <= 0 {
		return "", probe.NewError(errors.New("invalid part id, cannot be zero or less than zero"))
	}

	// Check bucket name valid.
	if !IsValidBucketName(bucket) {
		return "", probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	// Verify object path legal.
	if !IsValidObjectName(object) {
		return "", probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	// Verify upload is valid for the incoming object.
	if !fs.isValidUploadID(object, uploadID) {
		return "", probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	if strings.TrimSpace(expectedMD5Sum) != "" {
		var expectedMD5SumBytes []byte
		expectedMD5SumBytes, err = base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// Pro-actively close the connection
			return "", probe.NewError(InvalidDigest{MD5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	bucket = fs.denormalizeBucket(bucket)
	bucketPath := filepath.Join(fs.path, bucket)
	if _, err = os.Stat(bucketPath); err != nil {
		// Check bucket exists.
		if os.IsNotExist(err) {
			return "", probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return "", probe.NewError(err)
	}

	objectPath := filepath.Join(bucketPath, object)
	partPathPrefix := objectPath + uploadID
	partPath := partPathPrefix + expectedMD5Sum + fmt.Sprintf("$%d-$multiparts", partID)
	partFile, e := atomic.FileCreateWithPrefix(partPath, "$multiparts")
	if e != nil {
		return "", probe.NewError(e)
	}

	md5Hasher := md5.New()
	sha256Hasher := sha256.New()
	partWriter := io.MultiWriter(partFile, md5Hasher, sha256Hasher)
	if _, e = io.CopyN(partWriter, data, size); e != nil {
		partFile.CloseAndPurge()
		return "", probe.NewError(e)
	}

	md5sum := hex.EncodeToString(md5Hasher.Sum(nil))
	// Verify if the written object is equal to what is expected, only
	// if it is requested as such.
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if !isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5sum) {
			partFile.CloseAndPurge()
			return "", probe.NewError(BadDigest{MD5: expectedMD5Sum, Bucket: bucket, Object: object})
		}
	}
	if signature != nil {
		ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sha256Hasher.Sum(nil)))
		if err != nil {
			partFile.CloseAndPurge()
			return "", err.Trace()
		}
		if !ok {
			partFile.CloseAndPurge()
			return "", probe.NewError(signV4.SigDoesNotMatch{})
		}
	}
	partFile.Close()

	fi, e := os.Stat(partPath)
	if e != nil {
		return "", probe.NewError(e)
	}
	partMetadata := PartMetadata{}
	partMetadata.ETag = md5sum
	partMetadata.PartNumber = partID
	partMetadata.Size = fi.Size()
//.........這裏部分代碼省略.........

// PutBucketHandler - PUT Bucket
// ----------
// This implementation of the PUT operation creates a new bucket for authenticated request
func (api CloudStorageAPI) PutBucketHandler(w http.ResponseWriter, req *http.Request) {
	vars := mux.Vars(req)
	bucket := vars["bucket"]

	if isRequestRequiresACLCheck(req) {
		writeErrorResponse(w, req, AccessDenied, req.URL.Path)
		return
	}

	// read from 'x-amz-acl'
	aclType := getACLType(req)
	if aclType == unsupportedACLType {
		writeErrorResponse(w, req, NotImplemented, req.URL.Path)
		return
	}

	var signature *v4.Signature
	// Init signature V4 verification
	if isRequestSignatureV4(req) {
		var err *probe.Error
		signature, err = initSignatureV4(req)
		if err != nil {
			switch err.ToGoError() {
			case errInvalidRegion:
				errorIf(err.Trace(), "Unknown region in authorization header.", nil)
				writeErrorResponse(w, req, AuthorizationHeaderMalformed, req.URL.Path)
				return
			case errAccessKeyIDInvalid:
				errorIf(err.Trace(), "Invalid access key id.", nil)
				writeErrorResponse(w, req, InvalidAccessKeyID, req.URL.Path)
				return
			default:
				errorIf(err.Trace(), "Initializing signature v4 failed.", nil)
				writeErrorResponse(w, req, InternalError, req.URL.Path)
				return
			}
		}
	}

	// if body of request is non-nil then check for validity of Content-Length
	if req.Body != nil {
		/// if Content-Length is unknown/missing, deny the request
		if req.ContentLength == -1 && !contains(req.TransferEncoding, "chunked") {
			writeErrorResponse(w, req, MissingContentLength, req.URL.Path)
			return
		}
		if signature != nil {
			locationBytes, e := ioutil.ReadAll(req.Body)
			if e != nil {
				errorIf(probe.NewError(e), "MakeBucket failed.", nil)
				writeErrorResponse(w, req, InternalError, req.URL.Path)
				return
			}
			sh := sha256.New()
			sh.Write(locationBytes)
			ok, err := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
			if err != nil {
				errorIf(err.Trace(), "MakeBucket failed.", nil)
				writeErrorResponse(w, req, InternalError, req.URL.Path)
				return
			}
			if !ok {
				writeErrorResponse(w, req, SignatureDoesNotMatch, req.URL.Path)
				return
			}
		}
	}

	err := api.Filesystem.MakeBucket(bucket, getACLTypeString(aclType))
	if err != nil {
		errorIf(err.Trace(), "MakeBucket failed.", nil)
		switch err.ToGoError().(type) {
		case fs.BucketNameInvalid:
			writeErrorResponse(w, req, InvalidBucketName, req.URL.Path)
		case fs.BucketExists:
			writeErrorResponse(w, req, BucketAlreadyExists, req.URL.Path)
		default:
			writeErrorResponse(w, req, InternalError, req.URL.Path)
		}
		return
	}
	// Make sure to add Location information here only for bucket
	w.Header().Set("Location", "/"+bucket)
	writeSuccessResponse(w, nil)
}

// createObject - internal wrapper function called by CreateObjectPart
func (donut API) createObjectPart(bucket, key, uploadID string, partID int, contentType, expectedMD5Sum string, size int64, data io.Reader, signature *Signature) (string, *probe.Error) {
	if !IsValidBucket(bucket) {
		return "", probe.NewError(BucketNameInvalid{Bucket: bucket})
	}
	if !IsValidObjectName(key) {
		return "", probe.NewError(ObjectNameInvalid{Object: key})
	}
	// TODO: multipart support for donut is broken, since we haven't finalized the format in which
	//       it can be stored, disabling this for now until we get the underlying layout stable.
	//
	/*
		if len(donut.config.NodeDiskMap) > 0 {
			metadata := make(map[string]string)
			if contentType == "" {
				contentType = "application/octet-stream"
			}
			contentType = strings.TrimSpace(contentType)
			metadata["contentType"] = contentType
			if strings.TrimSpace(expectedMD5Sum) != "" {
				expectedMD5SumBytes, err := base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
				if err != nil {
					// pro-actively close the connection
					return "", probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
				}
				expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
			}
			partMetadata, err := donut.putObjectPart(bucket, key, expectedMD5Sum, uploadID, partID, data, size, metadata, signature)
			if err != nil {
				return "", err.Trace()
			}
			return partMetadata.ETag, nil
		}
	*/
	if !donut.storedBuckets.Exists(bucket) {
		return "", probe.NewError(BucketNotFound{Bucket: bucket})
	}
	strBucket := donut.storedBuckets.Get(bucket).(storedBucket)
	// Verify upload id
	if strBucket.multiPartSession[key].UploadID != uploadID {
		return "", probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	// get object key
	parts := strBucket.partMetadata[key]
	if _, ok := parts[partID]; ok {
		return parts[partID].ETag, nil
	}

	if contentType == "" {
		contentType = "application/octet-stream"
	}
	contentType = strings.TrimSpace(contentType)
	if strings.TrimSpace(expectedMD5Sum) != "" {
		expectedMD5SumBytes, err := base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// pro-actively close the connection
			return "", probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	// calculate md5
	hash := md5.New()
	sha256hash := sha256.New()

	var totalLength int64
	var err error
	for err == nil {
		var length int
		byteBuffer := make([]byte, 1024*1024)
		length, err = data.Read(byteBuffer) // do not read error return error here, we will handle this error later
		hash.Write(byteBuffer[0:length])
		sha256hash.Write(byteBuffer[0:length])
		ok := donut.multiPartObjects[uploadID].Append(partID, byteBuffer[0:length])
		if !ok {
			return "", probe.NewError(InternalError{})
		}
		totalLength += int64(length)
		go debug.FreeOSMemory()
	}
	if totalLength != size {
		donut.multiPartObjects[uploadID].Delete(partID)
		return "", probe.NewError(IncompleteBody{Bucket: bucket, Object: key})
	}
	if err != io.EOF {
		return "", probe.NewError(err)
	}

	md5SumBytes := hash.Sum(nil)
	md5Sum := hex.EncodeToString(md5SumBytes)
	// Verify if the written object is equal to what is expected, only if it is requested as such
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if err := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum); err != nil {
			return "", err.Trace()
		}
	}

	if signature != nil {
		{
//.........這裏部分代碼省略.........

// CreateObject - PUT object
func (fs API) CreateObject(bucket, object, expectedMD5Sum string, size int64, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
	fs.lock.Lock()
	defer fs.lock.Unlock()

	// check bucket name valid
	if !IsValidBucket(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}
	// check bucket exists
	if _, err := os.Stat(filepath.Join(fs.path, bucket)); os.IsNotExist(err) {
		return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
	}
	// verify object path legal
	if !IsValidObjectName(object) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	// get object path
	objectPath := filepath.Join(fs.path, bucket, object)
	if strings.TrimSpace(expectedMD5Sum) != "" {
		expectedMD5SumBytes, err := base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// pro-actively close the connection
			return ObjectMetadata{}, probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	// write object
	file, err := atomic.FileCreate(objectPath)
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}

	h := md5.New()
	sh := sha256.New()
	mw := io.MultiWriter(file, h, sh)

	if size > 0 {
		_, err = io.CopyN(mw, data, size)
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(err)
		}
	} else {
		_, err = io.Copy(mw, data)
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(err)
		}
	}

	md5Sum := hex.EncodeToString(h.Sum(nil))
	// Verify if the written object is equal to what is expected, only if it is requested as such
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if err := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum); err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(BadDigest{Md5: expectedMD5Sum, Bucket: bucket, Object: object})
		}
	}
	sha256Sum := hex.EncodeToString(sh.Sum(nil))
	if signature != nil {
		ok, perr := signature.DoesSignatureMatch(sha256Sum)
		if perr != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, perr.Trace()
		}
		if !ok {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(SignatureDoesNotMatch{})
		}
	}
	file.File.Sync()
	file.Close()

	st, err := os.Stat(objectPath)
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}
	newObject := ObjectMetadata{
		Bucket:      bucket,
		Object:      object,
		Created:     st.ModTime(),
		Size:        st.Size(),
		ContentType: "application/octet-stream",
		Md5:         md5Sum,
	}
	return newObject, nil
}

// sum256 calculate sha256 sum for an input byte array
func sum256(data []byte) []byte {
	hash := sha256.New()
	hash.Write(data)
	return hash.Sum(nil)
}

// CompleteMultipartUpload - complete a multipart upload and persist the data
func (fs API) CompleteMultipartUpload(bucket, object, uploadID string, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
	fs.lock.Lock()
	defer fs.lock.Unlock()

	// check bucket name valid
	if !IsValidBucket(bucket) {
		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	// verify object path legal
	if !IsValidObjectName(object) {
		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	if !fs.isValidUploadID(object, uploadID) {
		return ObjectMetadata{}, probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	bucketPath := filepath.Join(fs.path, bucket)
	if _, err := os.Stat(bucketPath); err != nil {
		// check bucket exists
		if os.IsNotExist(err) {
			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
		}
		return ObjectMetadata{}, probe.NewError(InternalError{})
	}

	objectPath := filepath.Join(bucketPath, object)
	file, err := atomic.FileCreate(objectPath)
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}
	h := md5.New()
	mw := io.MultiWriter(file, h)

	partBytes, err := ioutil.ReadAll(data)
	if err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(err)
	}
	if signature != nil {
		sh := sha256.New()
		sh.Write(partBytes)
		ok, perr := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
		if perr != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(err)
		}
		if !ok {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(SignatureDoesNotMatch{})
		}
	}
	parts := &CompleteMultipartUpload{}
	if err := xml.Unmarshal(partBytes, parts); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(MalformedXML{})
	}
	if !sort.IsSorted(completedParts(parts.Part)) {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(InvalidPartOrder{})
	}

	if err := fs.concatParts(parts, objectPath, mw); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, err.Trace()
	}

	delete(fs.multiparts.ActiveSession, object)
	for _, part := range parts.Part {
		err = os.Remove(objectPath + fmt.Sprintf("$%d", part.PartNumber))
		if err != nil {
			file.CloseAndPurge()
			return ObjectMetadata{}, probe.NewError(err)
		}
	}
	if err := os.Remove(objectPath + "$multiparts"); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, probe.NewError(err)
	}
	if err := SaveMultipartsSession(fs.multiparts); err != nil {
		file.CloseAndPurge()
		return ObjectMetadata{}, err.Trace()
	}
	file.File.Sync()
	file.Close()

	st, err := os.Stat(objectPath)
	if err != nil {
		return ObjectMetadata{}, probe.NewError(err)
	}
	newObject := ObjectMetadata{
		Bucket:      bucket,
		Object:      object,
		Created:     st.ModTime(),
		Size:        st.Size(),
		ContentType: "application/octet-stream",
		Md5:         hex.EncodeToString(h.Sum(nil)),
	}
//.........這裏部分代碼省略.........

// CreateObjectPart - create a part in a multipart session
func (fs API) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum string, partID int, size int64, data io.Reader, signature *Signature) (string, *probe.Error) {
	fs.lock.Lock()
	defer fs.lock.Unlock()

	if partID <= 0 {
		return "", probe.NewError(errors.New("invalid part id, cannot be zero or less than zero"))
	}
	// check bucket name valid
	if !IsValidBucket(bucket) {
		return "", probe.NewError(BucketNameInvalid{Bucket: bucket})
	}

	// verify object path legal
	if !IsValidObjectName(object) {
		return "", probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
	}

	if !fs.isValidUploadID(object, uploadID) {
		return "", probe.NewError(InvalidUploadID{UploadID: uploadID})
	}

	if strings.TrimSpace(expectedMD5Sum) != "" {
		expectedMD5SumBytes, err := base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
		if err != nil {
			// pro-actively close the connection
			return "", probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
		}
		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
	}

	bucketPath := filepath.Join(fs.path, bucket)
	if _, err := os.Stat(bucketPath); err != nil {
		// check bucket exists
		if os.IsNotExist(err) {
			return "", probe.NewError(BucketNotFound{Bucket: bucket})
		}
		if err != nil {
			return "", probe.NewError(InternalError{})
		}
	}

	objectPath := filepath.Join(bucketPath, object)
	partPath := objectPath + fmt.Sprintf("$%d", partID)
	partFile, err := atomic.FileCreate(partPath)
	if err != nil {
		return "", probe.NewError(err)
	}
	h := md5.New()
	sh := sha256.New()
	mw := io.MultiWriter(partFile, h, sh)
	_, err = io.CopyN(mw, data, size)
	if err != nil {
		partFile.CloseAndPurge()
		return "", probe.NewError(err)
	}
	md5sum := hex.EncodeToString(h.Sum(nil))
	// Verify if the written object is equal to what is expected, only if it is requested as such
	if strings.TrimSpace(expectedMD5Sum) != "" {
		if err := isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5sum); err != nil {
			partFile.CloseAndPurge()
			return "", probe.NewError(BadDigest{Md5: expectedMD5Sum, Bucket: bucket, Object: object})
		}
	}
	if signature != nil {
		ok, perr := signature.DoesSignatureMatch(hex.EncodeToString(sh.Sum(nil)))
		if perr != nil {
			partFile.CloseAndPurge()
			return "", perr.Trace()
		}
		if !ok {
			partFile.CloseAndPurge()
			return "", probe.NewError(SignatureDoesNotMatch{})
		}
	}
	partFile.File.Sync()
	partFile.Close()

	fi, err := os.Stat(partPath)
	if err != nil {
		return "", probe.NewError(err)
	}
	partMetadata := PartMetadata{}
	partMetadata.ETag = md5sum
	partMetadata.PartNumber = partID
	partMetadata.Size = fi.Size()
	partMetadata.LastModified = fi.ModTime()

	multiPartfile, err := os.OpenFile(objectPath+"$multiparts", os.O_RDWR|os.O_APPEND, 0600)
	if err != nil {
		return "", probe.NewError(err)
	}
	defer multiPartfile.Close()

	var deserializedMultipartSession MultipartSession
	decoder := json.NewDecoder(multiPartfile)
	err = decoder.Decode(&deserializedMultipartSession)
	if err != nil {
		return "", probe.NewError(err)
	}
//.........這裏部分代碼省略.........