public ObjectMetadata ResumableDownloadObject()

in sdk/OssClient.cs [1406:1481]
69 lines of code
10 McCabe index (conditional complexity)

        public ObjectMetadata ResumableDownloadObject(DownloadObjectRequest request)
        {
            ThrowIfNullRequest(request);
            ThrowIfNullRequest(request.BucketName);
            ThrowIfNullRequest(request.Key);
            ThrowIfNullRequest(request.DownloadFile);

            if (!Directory.GetParent(request.DownloadFile).Exists)
            {
                throw new ArgumentException(String.Format("Invalid file path {0}. The parent folder does not exist.", request.DownloadFile));
            }

            var metaRequest = new GetObjectMetadataRequest(request.BucketName, request.Key)
            {
                RequestPayer = request.RequestPayer,
                VersionId = request.VersionId
            };
            ObjectMetadata objectMeta = this.GetObjectMetadata(metaRequest);
            var fileSize = objectMeta.ContentLength;

            // Adjusts part size
            long actualPartSize = AdjustPartSize(request.PartSize);
            var config = OssUtils.GetClientConfiguration(_serviceClient);
            if (fileSize <= actualPartSize)
            {
                using (Stream fs = File.Open(request.DownloadFile, FileMode.Create))
                {
                    using (var ossObject = GetObject(request.ToGetObjectRequest()))
                    {
                        var streamWrapper = ossObject.Content;
                        try
                        {
                            if (config.EnalbeMD5Check && !string.IsNullOrEmpty(objectMeta.ContentMd5))
                            {
                                byte[] expectedHashDigest = Convert.FromBase64String(objectMeta.ContentMd5); ;
                                streamWrapper = new MD5Stream(ossObject.Content, expectedHashDigest, fileSize);
                            }
                            else if (config.EnableCrcCheck && !string.IsNullOrEmpty(objectMeta.Crc64))
                            {
                                ulong crcVal = 0;
                                if (UInt64.TryParse(objectMeta.Crc64, out crcVal))
                                {
                                    byte[] expectedHashDigest = BitConverter.GetBytes(crcVal);
                                    streamWrapper = new Crc64Stream(ossObject.Content, expectedHashDigest, fileSize);
                                }
                            }

                            if (request.StreamTransferProgress != null)
                            {
                                streamWrapper = this.SetupProgressListeners(streamWrapper,
                                                                            objectMeta.ContentLength,
                                                                            0,
                                                                            config.ProgressUpdateInterval,
                                                                            request.StreamTransferProgress);
                            }
                            ResumableDownloadManager.WriteTo(streamWrapper, fs);
                        }
                        finally
                        {
                            if (!Object.Equals(streamWrapper, fs))
                            {
                                streamWrapper.Dispose();
                            }
                        }
                    }
                }

                return objectMeta;
            }

            ResumableDownloadContext resumableContext = this.LoadResumableDownloadContext(request.BucketName, request.Key, request.VersionId, objectMeta, request.CheckpointDir, actualPartSize);
            ResumableDownloadManager resumableDownloadManager = new ResumableDownloadManager(this, ((RetryableServiceClient)_serviceClient).MaxRetryTimes, config);
            resumableDownloadManager.ResumableDownloadWithRetry(request, resumableContext);
            resumableContext.Clear();
            return objectMeta;
        }