// Package s3 provides an interface to Amazon S3 oject storage
package s3

// FIXME need to prevent anything but ListDir working for s3://

/*
Progress of port to aws-sdk

 * Don't really need o.meta at all?

What happens if you CTRL-C a multipart upload
  * get an incomplete upload
  * disappears when you delete the bucket
*/

import (
	"encoding/base64"
	"encoding/hex"
	"fmt"
	"io"
	"net/http"
	"path"
	"regexp"
	"strings"
	"sync"
	"time"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/awserr"
	"github.com/aws/aws-sdk-go/aws/corehandlers"
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds"
	"github.com/aws/aws-sdk-go/aws/defaults"
	"github.com/aws/aws-sdk-go/aws/ec2metadata"
	"github.com/aws/aws-sdk-go/aws/request"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/s3"
	"github.com/aws/aws-sdk-go/service/s3/s3manager"
	"github.com/ncw/rclone/fs"
	"github.com/ncw/rclone/fs/config/configmap"
	"github.com/ncw/rclone/fs/config/configstruct"
	"github.com/ncw/rclone/fs/fserrors"
	"github.com/ncw/rclone/fs/fshttp"
	"github.com/ncw/rclone/fs/hash"
	"github.com/ncw/rclone/fs/walk"
	"github.com/ncw/rclone/lib/pacer"
	"github.com/ncw/rclone/lib/rest"
	"github.com/ncw/swift"
	"github.com/pkg/errors"
)

// Register with Fs
func init() {
	fs.Register(&fs.RegInfo{
		Name:        "s3",
		Description: "Amazon S3 Compliant Storage Provider (AWS, Alibaba, Ceph, Digital Ocean, Dreamhost, IBM COS, Minio, etc)",
		NewFs:       NewFs,
		Options: []fs.Option{{
			Name: fs.ConfigProvider,
			Help: "Choose your S3 provider.",
			Examples: []fs.OptionExample{{
				Value: "AWS",
				Help:  "Amazon Web Services (AWS) S3",
			}, {
				Value: "Alibaba",
				Help:  "Alibaba Cloud Object Storage System (OSS) formerly Aliyun",
			}, {
				Value: "Ceph",
				Help:  "Ceph Object Storage",
			}, {
				Value: "DigitalOcean",
				Help:  "Digital Ocean Spaces",
			}, {
				Value: "Dreamhost",
				Help:  "Dreamhost DreamObjects",
			}, {
				Value: "IBMCOS",
				Help:  "IBM COS S3",
			}, {
				Value: "Minio",
				Help:  "Minio Object Storage",
			}, {
				Value: "Netease",
				Help:  "Netease Object Storage (NOS)",
			}, {
				Value: "Wasabi",
				Help:  "Wasabi Object Storage",
			}, {
				Value: "Other",
				Help:  "Any other S3 compatible provider",
			}},
		}, {
			Name:    "env_auth",
			Help:    "Get AWS credentials from runtime (environment variables or EC2/ECS meta data if no env vars).\nOnly applies if access_key_id and secret_access_key is blank.",
			Default: false,
			Examples: []fs.OptionExample{{
				Value: "false",
				Help:  "Enter AWS credentials in the next step",
			}, {
				Value: "true",
				Help:  "Get AWS credentials from the environment (env vars or IAM)",
			}},
		}, {
			Name: "access_key_id",
			Help: "AWS Access Key ID.\nLeave blank for anonymous access or runtime credentials.",
		}, {
			Name: "secret_access_key",
			Help: "AWS Secret Access Key (password)\nLeave blank for anonymous access or runtime credentials.",
		}, {
			Name:     "region",
			Help:     "Region to connect to.",
			Provider: "AWS",
			Examples: []fs.OptionExample{{
				Value: "us-east-1",
				Help:  "The default endpoint - a good choice if you are unsure.\nUS Region, Northern Virginia or Pacific Northwest.\nLeave location constraint empty.",
			}, {
				Value: "us-east-2",
				Help:  "US East (Ohio) Region\nNeeds location constraint us-east-2.",
			}, {
				Value: "us-west-2",
				Help:  "US West (Oregon) Region\nNeeds location constraint us-west-2.",
			}, {
				Value: "us-west-1",
				Help:  "US West (Northern California) Region\nNeeds location constraint us-west-1.",
			}, {
				Value: "ca-central-1",
				Help:  "Canada (Central) Region\nNeeds location constraint ca-central-1.",
			}, {
				Value: "eu-west-1",
				Help:  "EU (Ireland) Region\nNeeds location constraint EU or eu-west-1.",
			}, {
				Value: "eu-west-2",
				Help:  "EU (London) Region\nNeeds location constraint eu-west-2.",
			}, {
				Value: "eu-north-1",
				Help:  "EU (Stockholm) Region\nNeeds location constraint eu-north-1.",
			}, {
				Value: "eu-central-1",
				Help:  "EU (Frankfurt) Region\nNeeds location constraint eu-central-1.",
			}, {
				Value: "ap-southeast-1",
				Help:  "Asia Pacific (Singapore) Region\nNeeds location constraint ap-southeast-1.",
			}, {
				Value: "ap-southeast-2",
				Help:  "Asia Pacific (Sydney) Region\nNeeds location constraint ap-southeast-2.",
			}, {
				Value: "ap-northeast-1",
				Help:  "Asia Pacific (Tokyo) Region\nNeeds location constraint ap-northeast-1.",
			}, {
				Value: "ap-northeast-2",
				Help:  "Asia Pacific (Seoul)\nNeeds location constraint ap-northeast-2.",
			}, {
				Value: "ap-south-1",
				Help:  "Asia Pacific (Mumbai)\nNeeds location constraint ap-south-1.",
			}, {
				Value: "sa-east-1",
				Help:  "South America (Sao Paulo) Region\nNeeds location constraint sa-east-1.",
			}},
		}, {
			Name:     "region",
			Help:     "Region to connect to.\nLeave blank if you are using an S3 clone and you don't have a region.",
			Provider: "!AWS,Alibaba",
			Examples: []fs.OptionExample{{
				Value: "",
				Help:  "Use this if unsure. Will use v4 signatures and an empty region.",
			}, {
				Value: "other-v2-signature",
				Help:  "Use this only if v4 signatures don't work, eg pre Jewel/v10 CEPH.",
			}},
		}, {
			Name:     "endpoint",
			Help:     "Endpoint for S3 API.\nLeave blank if using AWS to use the default endpoint for the region.",
			Provider: "AWS",
		}, {
			Name:     "endpoint",
			Help:     "Endpoint for IBM COS S3 API.\nSpecify if using an IBM COS On Premise.",
			Provider: "IBMCOS",
			Examples: []fs.OptionExample{{
				Value: "s3-api.us-geo.objectstorage.softlayer.net",
				Help:  "US Cross Region Endpoint",
			}, {
				Value: "s3-api.dal.us-geo.objectstorage.softlayer.net",
				Help:  "US Cross Region Dallas Endpoint",
			}, {
				Value: "s3-api.wdc-us-geo.objectstorage.softlayer.net",
				Help:  "US Cross Region Washington DC Endpoint",
			}, {
				Value: "s3-api.sjc-us-geo.objectstorage.softlayer.net",
				Help:  "US Cross Region San Jose Endpoint",
			}, {
				Value: "s3-api.us-geo.objectstorage.service.networklayer.com",
				Help:  "US Cross Region Private Endpoint",
			}, {
				Value: "s3-api.dal-us-geo.objectstorage.service.networklayer.com",
				Help:  "US Cross Region Dallas Private Endpoint",
			}, {
				Value: "s3-api.wdc-us-geo.objectstorage.service.networklayer.com",
				Help:  "US Cross Region Washington DC Private Endpoint",
			}, {
				Value: "s3-api.sjc-us-geo.objectstorage.service.networklayer.com",
				Help:  "US Cross Region San Jose Private Endpoint",
			}, {
				Value: "s3.us-east.objectstorage.softlayer.net",
				Help:  "US Region East Endpoint",
			}, {
				Value: "s3.us-east.objectstorage.service.networklayer.com",
				Help:  "US Region East Private Endpoint",
			}, {
				Value: "s3.us-south.objectstorage.softlayer.net",
				Help:  "US Region South Endpoint",
			}, {
				Value: "s3.us-south.objectstorage.service.networklayer.com",
				Help:  "US Region South Private Endpoint",
			}, {
				Value: "s3.eu-geo.objectstorage.softlayer.net",
				Help:  "EU Cross Region Endpoint",
			}, {
				Value: "s3.fra-eu-geo.objectstorage.softlayer.net",
				Help:  "EU Cross Region Frankfurt Endpoint",
			}, {
				Value: "s3.mil-eu-geo.objectstorage.softlayer.net",
				Help:  "EU Cross Region Milan Endpoint",
			}, {
				Value: "s3.ams-eu-geo.objectstorage.softlayer.net",
				Help:  "EU Cross Region Amsterdam Endpoint",
			}, {
				Value: "s3.eu-geo.objectstorage.service.networklayer.com",
				Help:  "EU Cross Region Private Endpoint",
			}, {
				Value: "s3.fra-eu-geo.objectstorage.service.networklayer.com",
				Help:  "EU Cross Region Frankfurt Private Endpoint",
			}, {
				Value: "s3.mil-eu-geo.objectstorage.service.networklayer.com",
				Help:  "EU Cross Region Milan Private Endpoint",
			}, {
				Value: "s3.ams-eu-geo.objectstorage.service.networklayer.com",
				Help:  "EU Cross Region Amsterdam Private Endpoint",
			}, {
				Value: "s3.eu-gb.objectstorage.softlayer.net",
				Help:  "Great Britain Endpoint",
			}, {
				Value: "s3.eu-gb.objectstorage.service.networklayer.com",
				Help:  "Great Britain Private Endpoint",
			}, {
				Value: "s3.ap-geo.objectstorage.softlayer.net",
				Help:  "APAC Cross Regional Endpoint",
			}, {
				Value: "s3.tok-ap-geo.objectstorage.softlayer.net",
				Help:  "APAC Cross Regional Tokyo Endpoint",
			}, {
				Value: "s3.hkg-ap-geo.objectstorage.softlayer.net",
				Help:  "APAC Cross Regional HongKong Endpoint",
			}, {
				Value: "s3.seo-ap-geo.objectstorage.softlayer.net",
				Help:  "APAC Cross Regional Seoul Endpoint",
			}, {
				Value: "s3.ap-geo.objectstorage.service.networklayer.com",
				Help:  "APAC Cross Regional Private Endpoint",
			}, {
				Value: "s3.tok-ap-geo.objectstorage.service.networklayer.com",
				Help:  "APAC Cross Regional Tokyo Private Endpoint",
			}, {
				Value: "s3.hkg-ap-geo.objectstorage.service.networklayer.com",
				Help:  "APAC Cross Regional HongKong Private Endpoint",
			}, {
				Value: "s3.seo-ap-geo.objectstorage.service.networklayer.com",
				Help:  "APAC Cross Regional Seoul Private Endpoint",
			}, {
				Value: "s3.mel01.objectstorage.softlayer.net",
				Help:  "Melbourne Single Site Endpoint",
			}, {
				Value: "s3.mel01.objectstorage.service.networklayer.com",
				Help:  "Melbourne Single Site Private Endpoint",
			}, {
				Value: "s3.tor01.objectstorage.softlayer.net",
				Help:  "Toronto Single Site Endpoint",
			}, {
				Value: "s3.tor01.objectstorage.service.networklayer.com",
				Help:  "Toronto Single Site Private Endpoint",
			}},
		}, {
			// oss endpoints: https://help.aliyun.com/document_detail/31837.html
			Name:     "endpoint",
			Help:     "Endpoint for OSS API.",
			Provider: "Alibaba",
			Examples: []fs.OptionExample{{
				Value: "oss-cn-hangzhou.aliyuncs.com",
				Help:  "East China 1 (Hangzhou)",
			}, {
				Value: "oss-cn-shanghai.aliyuncs.com",
				Help:  "East China 2 (Shanghai)",
			}, {
				Value: "oss-cn-qingdao.aliyuncs.com",
				Help:  "North China 1 (Qingdao)",
			}, {
				Value: "oss-cn-beijing.aliyuncs.com",
				Help:  "North China 2 (Beijing)",
			}, {
				Value: "oss-cn-zhangjiakou.aliyuncs.com",
				Help:  "North China 3 (Zhangjiakou)",
			}, {
				Value: "oss-cn-huhehaote.aliyuncs.com",
				Help:  "North China 5 (Huhehaote)",
			}, {
				Value: "oss-cn-shenzhen.aliyuncs.com",
				Help:  "South China 1 (Shenzhen)",
			}, {
				Value: "oss-cn-hongkong.aliyuncs.com",
				Help:  "Hong Kong (Hong Kong)",
			}, {
				Value: "oss-us-west-1.aliyuncs.com",
				Help:  "US West 1 (Silicon Valley)",
			}, {
				Value: "oss-us-east-1.aliyuncs.com",
				Help:  "US East 1 (Virginia)",
			}, {
				Value: "oss-ap-southeast-1.aliyuncs.com",
				Help:  "Southeast Asia Southeast 1 (Singapore)",
			}, {
				Value: "oss-ap-southeast-2.aliyuncs.com",
				Help:  "Asia Pacific Southeast 2 (Sydney)",
			}, {
				Value: "oss-ap-southeast-3.aliyuncs.com",
				Help:  "Southeast Asia Southeast 3 (Kuala Lumpur)",
			}, {
				Value: "oss-ap-southeast-5.aliyuncs.com",
				Help:  "Asia Pacific Southeast 5 (Jakarta)",
			}, {
				Value: "oss-ap-northeast-1.aliyuncs.com",
				Help:  "Asia Pacific Northeast 1 (Japan)",
			}, {
				Value: "oss-ap-south-1.aliyuncs.com",
				Help:  "Asia Pacific South 1 (Mumbai)",
			}, {
				Value: "oss-eu-central-1.aliyuncs.com",
				Help:  "Central Europe 1 (Frankfurt)",
			}, {
				Value: "oss-eu-west-1.aliyuncs.com",
				Help:  "West Europe (London)",
			}, {
				Value: "oss-me-east-1.aliyuncs.com",
				Help:  "Middle East 1 (Dubai)",
			}},
		}, {
			Name:     "endpoint",
			Help:     "Endpoint for S3 API.\nRequired when using an S3 clone.",
			Provider: "!AWS,IBMCOS,Alibaba",
			Examples: []fs.OptionExample{{
				Value:    "objects-us-east-1.dream.io",
				Help:     "Dream Objects endpoint",
				Provider: "Dreamhost",
			}, {
				Value:    "nyc3.digitaloceanspaces.com",
				Help:     "Digital Ocean Spaces New York 3",
				Provider: "DigitalOcean",
			}, {
				Value:    "ams3.digitaloceanspaces.com",
				Help:     "Digital Ocean Spaces Amsterdam 3",
				Provider: "DigitalOcean",
			}, {
				Value:    "sgp1.digitaloceanspaces.com",
				Help:     "Digital Ocean Spaces Singapore 1",
				Provider: "DigitalOcean",
			}, {
				Value:    "s3.wasabisys.com",
				Help:     "Wasabi US East endpoint",
				Provider: "Wasabi",
			}, {
				Value:    "s3.us-west-1.wasabisys.com",
				Help:     "Wasabi US West endpoint",
				Provider: "Wasabi",
			}},
		}, {
			Name:     "location_constraint",
			Help:     "Location constraint - must be set to match the Region.\nUsed when creating buckets only.",
			Provider: "AWS",
			Examples: []fs.OptionExample{{
				Value: "",
				Help:  "Empty for US Region, Northern Virginia or Pacific Northwest.",
			}, {
				Value: "us-east-2",
				Help:  "US East (Ohio) Region.",
			}, {
				Value: "us-west-2",
				Help:  "US West (Oregon) Region.",
			}, {
				Value: "us-west-1",
				Help:  "US West (Northern California) Region.",
			}, {
				Value: "ca-central-1",
				Help:  "Canada (Central) Region.",
			}, {
				Value: "eu-west-1",
				Help:  "EU (Ireland) Region.",
			}, {
				Value: "eu-west-2",
				Help:  "EU (London) Region.",
			}, {
				Value: "eu-north-1",
				Help:  "EU (Stockholm) Region.",
			}, {
				Value: "EU",
				Help:  "EU Region.",
			}, {
				Value: "ap-southeast-1",
				Help:  "Asia Pacific (Singapore) Region.",
			}, {
				Value: "ap-southeast-2",
				Help:  "Asia Pacific (Sydney) Region.",
			}, {
				Value: "ap-northeast-1",
				Help:  "Asia Pacific (Tokyo) Region.",
			}, {
				Value: "ap-northeast-2",
				Help:  "Asia Pacific (Seoul)",
			}, {
				Value: "ap-south-1",
				Help:  "Asia Pacific (Mumbai)",
			}, {
				Value: "sa-east-1",
				Help:  "South America (Sao Paulo) Region.",
			}},
		}, {
			Name:     "location_constraint",
			Help:     "Location constraint - must match endpoint when using IBM Cloud Public.\nFor on-prem COS, do not make a selection from this list, hit enter",
			Provider: "IBMCOS",
			Examples: []fs.OptionExample{{
				Value: "us-standard",
				Help:  "US Cross Region Standard",
			}, {
				Value: "us-vault",
				Help:  "US Cross Region Vault",
			}, {
				Value: "us-cold",
				Help:  "US Cross Region Cold",
			}, {
				Value: "us-flex",
				Help:  "US Cross Region Flex",
			}, {
				Value: "us-east-standard",
				Help:  "US East Region Standard",
			}, {
				Value: "us-east-vault",
				Help:  "US East Region Vault",
			}, {
				Value: "us-east-cold",
				Help:  "US East Region Cold",
			}, {
				Value: "us-east-flex",
				Help:  "US East Region Flex",
			}, {
				Value: "us-south-standard",
				Help:  "US South Region Standard",
			}, {
				Value: "us-south-vault",
				Help:  "US South Region Vault",
			}, {
				Value: "us-south-cold",
				Help:  "US South Region Cold",
			}, {
				Value: "us-south-flex",
				Help:  "US South Region Flex",
			}, {
				Value: "eu-standard",
				Help:  "EU Cross Region Standard",
			}, {
				Value: "eu-vault",
				Help:  "EU Cross Region Vault",
			}, {
				Value: "eu-cold",
				Help:  "EU Cross Region Cold",
			}, {
				Value: "eu-flex",
				Help:  "EU Cross Region Flex",
			}, {
				Value: "eu-gb-standard",
				Help:  "Great Britain Standard",
			}, {
				Value: "eu-gb-vault",
				Help:  "Great Britain Vault",
			}, {
				Value: "eu-gb-cold",
				Help:  "Great Britain Cold",
			}, {
				Value: "eu-gb-flex",
				Help:  "Great Britain Flex",
			}, {
				Value: "ap-standard",
				Help:  "APAC Standard",
			}, {
				Value: "ap-vault",
				Help:  "APAC Vault",
			}, {
				Value: "ap-cold",
				Help:  "APAC Cold",
			}, {
				Value: "ap-flex",
				Help:  "APAC Flex",
			}, {
				Value: "mel01-standard",
				Help:  "Melbourne Standard",
			}, {
				Value: "mel01-vault",
				Help:  "Melbourne Vault",
			}, {
				Value: "mel01-cold",
				Help:  "Melbourne Cold",
			}, {
				Value: "mel01-flex",
				Help:  "Melbourne Flex",
			}, {
				Value: "tor01-standard",
				Help:  "Toronto Standard",
			}, {
				Value: "tor01-vault",
				Help:  "Toronto Vault",
			}, {
				Value: "tor01-cold",
				Help:  "Toronto Cold",
			}, {
				Value: "tor01-flex",
				Help:  "Toronto Flex",
			}},
		}, {
			Name:     "location_constraint",
			Help:     "Location constraint - must be set to match the Region.\nLeave blank if not sure. Used when creating buckets only.",
			Provider: "!AWS,IBMCOS,Alibaba",
		}, {
			Name: "acl",
			Help: `Canned ACL used when creating buckets and storing or copying objects.

This ACL is used for creating objects and if bucket_acl isn't set, for creating buckets too.

For more info visit https://docs.aws.amazon.com/AmazonS3/latest/dev/acl-overview.html#canned-acl

Note that this ACL is applied when server side copying objects as S3
doesn't copy the ACL from the source but rather writes a fresh one.`,
			Examples: []fs.OptionExample{{
				Value:    "private",
				Help:     "Owner gets FULL_CONTROL. No one else has access rights (default).",
				Provider: "!IBMCOS",
			}, {
				Value:    "public-read",
				Help:     "Owner gets FULL_CONTROL. The AllUsers group gets READ access.",
				Provider: "!IBMCOS",
			}, {
				Value:    "public-read-write",
				Help:     "Owner gets FULL_CONTROL. The AllUsers group gets READ and WRITE access.\nGranting this on a bucket is generally not recommended.",
				Provider: "!IBMCOS",
			}, {
				Value:    "authenticated-read",
				Help:     "Owner gets FULL_CONTROL. The AuthenticatedUsers group gets READ access.",
				Provider: "!IBMCOS",
			}, {
				Value:    "bucket-owner-read",
				Help:     "Object owner gets FULL_CONTROL. Bucket owner gets READ access.\nIf you specify this canned ACL when creating a bucket, Amazon S3 ignores it.",
				Provider: "!IBMCOS",
			}, {
				Value:    "bucket-owner-full-control",
				Help:     "Both the object owner and the bucket owner get FULL_CONTROL over the object.\nIf you specify this canned ACL when creating a bucket, Amazon S3 ignores it.",
				Provider: "!IBMCOS",
			}, {
				Value:    "private",
				Help:     "Owner gets FULL_CONTROL. No one else has access rights (default). This acl is available on IBM Cloud (Infra), IBM Cloud (Storage), On-Premise COS",
				Provider: "IBMCOS",
			}, {
				Value:    "public-read",
				Help:     "Owner gets FULL_CONTROL. The AllUsers group gets READ access. This acl is available on IBM Cloud (Infra), IBM Cloud (Storage), On-Premise IBM COS",
				Provider: "IBMCOS",
			}, {
				Value:    "public-read-write",
				Help:     "Owner gets FULL_CONTROL. The AllUsers group gets READ and WRITE access. This acl is available on IBM Cloud (Infra), On-Premise IBM COS",
				Provider: "IBMCOS",
			}, {
				Value:    "authenticated-read",
				Help:     "Owner gets FULL_CONTROL. The AuthenticatedUsers group gets READ access. Not supported on Buckets. This acl is available on IBM Cloud (Infra) and On-Premise IBM COS",
				Provider: "IBMCOS",
			}},
		}, {
			Name: "bucket_acl",
			Help: `Canned ACL used when creating buckets.

For more info visit https://docs.aws.amazon.com/AmazonS3/latest/dev/acl-overview.html#canned-acl

Note that this ACL is applied when only when creating buckets.  If it
isn't set then "acl" is used instead.`,
			Advanced: true,
			Examples: []fs.OptionExample{{
				Value: "private",
				Help:  "Owner gets FULL_CONTROL. No one else has access rights (default).",
			}, {
				Value: "public-read",
				Help:  "Owner gets FULL_CONTROL. The AllUsers group gets READ access.",
			}, {
				Value: "public-read-write",
				Help:  "Owner gets FULL_CONTROL. The AllUsers group gets READ and WRITE access.\nGranting this on a bucket is generally not recommended.",
			}, {
				Value: "authenticated-read",
				Help:  "Owner gets FULL_CONTROL. The AuthenticatedUsers group gets READ access.",
			}},
		}, {
			Name:     "server_side_encryption",
			Help:     "The server-side encryption algorithm used when storing this object in S3.",
			Provider: "AWS",
			Examples: []fs.OptionExample{{
				Value: "",
				Help:  "None",
			}, {
				Value: "AES256",
				Help:  "AES256",
			}, {
				Value: "aws:kms",
				Help:  "aws:kms",
			}},
		}, {
			Name:     "sse_kms_key_id",
			Help:     "If using KMS ID you must provide the ARN of Key.",
			Provider: "AWS",
			Examples: []fs.OptionExample{{
				Value: "",
				Help:  "None",
			}, {
				Value: "arn:aws:kms:us-east-1:*",
				Help:  "arn:aws:kms:*",
			}},
		}, {
			Name:     "storage_class",
			Help:     "The storage class to use when storing new objects in S3.",
			Provider: "AWS",
			Examples: []fs.OptionExample{{
				Value: "",
				Help:  "Default",
			}, {
				Value: "STANDARD",
				Help:  "Standard storage class",
			}, {
				Value: "REDUCED_REDUNDANCY",
				Help:  "Reduced redundancy storage class",
			}, {
				Value: "STANDARD_IA",
				Help:  "Standard Infrequent Access storage class",
			}, {
				Value: "ONEZONE_IA",
				Help:  "One Zone Infrequent Access storage class",
			}, {
				Value: "GLACIER",
				Help:  "Glacier storage class",
			}, {
				Value: "DEEP_ARCHIVE",
				Help:  "Glacier Deep Archive storage class",
			}},
		}, {
			// Mapping from here: https://www.alibabacloud.com/help/doc-detail/64919.htm
			Name:     "storage_class",
			Help:     "The storage class to use when storing new objects in OSS.",
			Provider: "Alibaba",
			Examples: []fs.OptionExample{{
				Value: "",
				Help:  "Default",
			}, {
				Value: "STANDARD",
				Help:  "Standard storage class",
			}, {
				Value: "GLACIER",
				Help:  "Archive storage mode.",
			}, {
				Value: "STANDARD_IA",
				Help:  "Infrequent access storage mode.",
			}},
		}, {
			Name: "upload_cutoff",
			Help: `Cutoff for switching to chunked upload

Any files larger than this will be uploaded in chunks of chunk_size.
The minimum is 0 and the maximum is 5GB.`,
			Default:  defaultUploadCutoff,
			Advanced: true,
		}, {
			Name: "chunk_size",
			Help: `Chunk size to use for uploading.

When uploading files larger than upload_cutoff they will be uploaded
as multipart uploads using this chunk size.

Note that "--s3-upload-concurrency" chunks of this size are buffered
in memory per transfer.

If you are transferring large files over high speed links and you have
enough memory, then increasing this will speed up the transfers.`,
			Default:  minChunkSize,
			Advanced: true,
		}, {
			Name:     "disable_checksum",
			Help:     "Don't store MD5 checksum with object metadata",
			Default:  false,
			Advanced: true,
		}, {
			Name:     "session_token",
			Help:     "An AWS session token",
			Advanced: true,
		}, {
			Name: "upload_concurrency",
			Help: `Concurrency for multipart uploads.

This is the number of chunks of the same file that are uploaded
concurrently.

If you are uploading small numbers of large file over high speed link
and these uploads do not fully utilize your bandwidth, then increasing
this may help to speed up the transfers.`,
			Default:  4,
			Advanced: true,
		}, {
			Name: "force_path_style",
			Help: `If true use path style access if false use virtual hosted style.

If this is true (the default) then rclone will use path style access,
if false then rclone will use virtual path style. See [the AWS S3
docs](https://docs.aws.amazon.com/AmazonS3/latest/dev/UsingBucket.html#access-bucket-intro)
for more info.

Some providers (eg Aliyun OSS or Netease COS) require this set to false.`,
			Default:  true,
			Advanced: true,
		}, {
			Name: "v2_auth",
			Help: `If true use v2 authentication.

If this is false (the default) then rclone will use v4 authentication.
If it is set then rclone will use v2 authentication.

Use this only if v4 signatures don't work, eg pre Jewel/v10 CEPH.`,
			Default:  false,
			Advanced: true,
		}, {
			Name:     "use_accelerate_endpoint",
			Provider: "AWS",
			Help: `If true use the AWS S3 accelerated endpoint.

See: [AWS S3 Transfer acceleration](https://docs.aws.amazon.com/AmazonS3/latest/dev/transfer-acceleration-examples.html)`,
			Default:  false,
			Advanced: true,
		}},
	})
}

// Constants
const (
	metaMtime           = "Mtime"                       // the meta key to store mtime in - eg X-Amz-Meta-Mtime
	metaMD5Hash         = "Md5chksum"                   // the meta key to store md5hash in
	listChunkSize       = 1000                          // number of items to read at once
	maxRetries          = 10                            // number of retries to make of operations
	maxSizeForCopy      = 5 * 1024 * 1024 * 1024        // The maximum size of object we can COPY
	maxFileSize         = 5 * 1024 * 1024 * 1024 * 1024 // largest possible upload file size
	minChunkSize        = fs.SizeSuffix(s3manager.MinUploadPartSize)
	defaultUploadCutoff = fs.SizeSuffix(200 * 1024 * 1024)
	maxUploadCutoff     = fs.SizeSuffix(5 * 1024 * 1024 * 1024)
	minSleep            = 10 * time.Millisecond // In case of error, start at 10ms sleep.
)

// Options defines the configuration for this backend
type Options struct {
	Provider              string        `config:"provider"`
	EnvAuth               bool          `config:"env_auth"`
	AccessKeyID           string        `config:"access_key_id"`
	SecretAccessKey       string        `config:"secret_access_key"`
	Region                string        `config:"region"`
	Endpoint              string        `config:"endpoint"`
	LocationConstraint    string        `config:"location_constraint"`
	ACL                   string        `config:"acl"`
	BucketACL             string        `config:"bucket_acl"`
	ServerSideEncryption  string        `config:"server_side_encryption"`
	SSEKMSKeyID           string        `config:"sse_kms_key_id"`
	StorageClass          string        `config:"storage_class"`
	UploadCutoff          fs.SizeSuffix `config:"upload_cutoff"`
	ChunkSize             fs.SizeSuffix `config:"chunk_size"`
	DisableChecksum       bool          `config:"disable_checksum"`
	SessionToken          string        `config:"session_token"`
	UploadConcurrency     int           `config:"upload_concurrency"`
	ForcePathStyle        bool          `config:"force_path_style"`
	V2Auth                bool          `config:"v2_auth"`
	UseAccelerateEndpoint bool          `config:"use_accelerate_endpoint"`
}

// Fs represents a remote s3 server
type Fs struct {
	name          string           // the name of the remote
	root          string           // root of the bucket - ignore all objects above this
	opt           Options          // parsed options
	features      *fs.Features     // optional features
	c             *s3.S3           // the connection to the s3 server
	ses           *session.Session // the s3 session
	bucket        string           // the bucket we are working on
	bucketOKMu    sync.Mutex       // mutex to protect bucket OK
	bucketOK      bool             // true if we have created the bucket
	bucketDeleted bool             // true if we have deleted the bucket
	pacer         *fs.Pacer        // To pace the API calls
	srv           *http.Client     // a plain http client
}

// Object describes a s3 object
type Object struct {
	// Will definitely have everything but meta which may be nil
	//
	// List will read everything but meta & mimeType - to fill
	// that in you need to call readMetaData
	fs           *Fs                // what this object is part of
	remote       string             // The remote path
	etag         string             // md5sum of the object
	bytes        int64              // size of the object
	lastModified time.Time          // Last modified
	meta         map[string]*string // The object metadata if known - may be nil
	mimeType     string             // MimeType of object - may be ""
}

// ------------------------------------------------------------

// Name of the remote (as passed into NewFs)
func (f *Fs) Name() string {
	return f.name
}

// Root of the remote (as passed into NewFs)
func (f *Fs) Root() string {
	if f.root == "" {
		return f.bucket
	}
	return f.bucket + "/" + f.root
}

// String converts this Fs to a string
func (f *Fs) String() string {
	if f.root == "" {
		return fmt.Sprintf("S3 bucket %s", f.bucket)
	}
	return fmt.Sprintf("S3 bucket %s path %s", f.bucket, f.root)
}

// Features returns the optional features of this Fs
func (f *Fs) Features() *fs.Features {
	return f.features
}

// retryErrorCodes is a slice of error codes that we will retry
// See: https://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html
var retryErrorCodes = []int{
	// 409, // Conflict - various states that could be resolved on a retry
	503, // Service Unavailable/Slow Down - "Reduce your request rate"
}

//S3 is pretty resilient, and the built in retry handling is probably sufficient
// as it should notice closed connections and timeouts which are the most likely
// sort of failure modes
func (f *Fs) shouldRetry(err error) (bool, error) {
	// If this is an awserr object, try and extract more useful information to determine if we should retry
	if awsError, ok := err.(awserr.Error); ok {
		// Simple case, check the original embedded error in case it's generically retryable
		if fserrors.ShouldRetry(awsError.OrigErr()) {
			return true, err
		}
		// Failing that, if it's a RequestFailure it's probably got an http status code we can check
		if reqErr, ok := err.(awserr.RequestFailure); ok {
			// 301 if wrong region for bucket
			if reqErr.StatusCode() == http.StatusMovedPermanently {
				urfbErr := f.updateRegionForBucket()
				if urfbErr != nil {
					fs.Errorf(f, "Failed to update region for bucket: %v", urfbErr)
					return false, err
				}
				return true, err
			}
			for _, e := range retryErrorCodes {
				if reqErr.StatusCode() == e {
					return true, err
				}
			}
		}
	}
	// Ok, not an awserr, check for generic failure conditions
	return fserrors.ShouldRetry(err), err
}

// Pattern to match a s3 path
var matcher = regexp.MustCompile(`^/*([^/]*)(.*)$`)

// parseParse parses a s3 'url'
func s3ParsePath(path string) (bucket, directory string, err error) {
	parts := matcher.FindStringSubmatch(path)
	if parts == nil {
		err = errors.Errorf("couldn't parse bucket out of s3 path %q", path)
	} else {
		bucket, directory = parts[1], parts[2]
		directory = strings.Trim(directory, "/")
	}
	return
}

// s3Connection makes a connection to s3
func s3Connection(opt *Options) (*s3.S3, *session.Session, error) {
	// Make the auth
	v := credentials.Value{
		AccessKeyID:     opt.AccessKeyID,
		SecretAccessKey: opt.SecretAccessKey,
		SessionToken:    opt.SessionToken,
	}

	lowTimeoutClient := &http.Client{Timeout: 1 * time.Second} // low timeout to ec2 metadata service
	def := defaults.Get()
	def.Config.HTTPClient = lowTimeoutClient

	// first provider to supply a credential set "wins"
	providers := []credentials.Provider{
		// use static credentials if they're present (checked by provider)
		&credentials.StaticProvider{Value: v},

		// * Access Key ID:     AWS_ACCESS_KEY_ID or AWS_ACCESS_KEY
		// * Secret Access Key: AWS_SECRET_ACCESS_KEY or AWS_SECRET_KEY
		&credentials.EnvProvider{},

		// A SharedCredentialsProvider retrieves credentials
		// from the current user's home directory.  It checks
		// AWS_SHARED_CREDENTIALS_FILE and AWS_PROFILE too.
		&credentials.SharedCredentialsProvider{},

		// Pick up IAM role if we're in an ECS task
		defaults.RemoteCredProvider(*def.Config, def.Handlers),

		// Pick up IAM role in case we're on EC2
		&ec2rolecreds.EC2RoleProvider{
			Client: ec2metadata.New(session.New(), &aws.Config{
				HTTPClient: lowTimeoutClient,
			}),
			ExpiryWindow: 3,
		},
	}
	cred := credentials.NewChainCredentials(providers)

	switch {
	case opt.EnvAuth:
		// No need for empty checks if "env_auth" is true
	case v.AccessKeyID == "" && v.SecretAccessKey == "":
		// if no access key/secret and iam is explicitly disabled then fall back to anon interaction
		cred = credentials.AnonymousCredentials
	case v.AccessKeyID == "":
		return nil, nil, errors.New("access_key_id not found")
	case v.SecretAccessKey == "":
		return nil, nil, errors.New("secret_access_key not found")
	}

	if opt.Region == "" && opt.Endpoint == "" {
		opt.Endpoint = "https://s3.amazonaws.com/"
	}
	if opt.Region == "" {
		opt.Region = "us-east-1"
	}
	if opt.Provider == "Alibaba" || opt.Provider == "Netease" || opt.UseAccelerateEndpoint {
		opt.ForcePathStyle = false
	}
	awsConfig := aws.NewConfig().
		WithMaxRetries(maxRetries).
		WithCredentials(cred).
		WithHTTPClient(fshttp.NewClient(fs.Config)).
		WithS3ForcePathStyle(opt.ForcePathStyle).
		WithS3UseAccelerate(opt.UseAccelerateEndpoint)
	if opt.Region != "" {
		awsConfig.WithRegion(opt.Region)
	}
	if opt.Endpoint != "" {
		awsConfig.WithEndpoint(opt.Endpoint)
	}

	// awsConfig.WithLogLevel(aws.LogDebugWithSigning)
	awsSessionOpts := session.Options{
		Config: *awsConfig,
	}
	if opt.EnvAuth && opt.AccessKeyID == "" && opt.SecretAccessKey == "" {
		// Enable loading config options from ~/.aws/config (selected by AWS_PROFILE env)
		awsSessionOpts.SharedConfigState = session.SharedConfigEnable
		// The session constructor (aws/session/mergeConfigSrcs) will only use the user's preferred credential source
		// (from the shared config file) if the passed-in Options.Config.Credentials is nil.
		awsSessionOpts.Config.Credentials = nil
	}
	ses, err := session.NewSessionWithOptions(awsSessionOpts)
	if err != nil {
		return nil, nil, err
	}
	c := s3.New(ses)
	if opt.V2Auth || opt.Region == "other-v2-signature" {
		fs.Debugf(nil, "Using v2 auth")
		signer := func(req *request.Request) {
			// Ignore AnonymousCredentials object
			if req.Config.Credentials == credentials.AnonymousCredentials {
				return
			}
			sign(v.AccessKeyID, v.SecretAccessKey, req.HTTPRequest)
		}
		c.Handlers.Sign.Clear()
		c.Handlers.Sign.PushBackNamed(corehandlers.BuildContentLengthHandler)
		c.Handlers.Sign.PushBack(signer)
	}
	return c, ses, nil
}

func checkUploadChunkSize(cs fs.SizeSuffix) error {
	if cs < minChunkSize {
		return errors.Errorf("%s is less than %s", cs, minChunkSize)
	}
	return nil
}

func (f *Fs) setUploadChunkSize(cs fs.SizeSuffix) (old fs.SizeSuffix, err error) {
	err = checkUploadChunkSize(cs)
	if err == nil {
		old, f.opt.ChunkSize = f.opt.ChunkSize, cs
	}
	return
}

func checkUploadCutoff(cs fs.SizeSuffix) error {
	if cs > maxUploadCutoff {
		return errors.Errorf("%s is greater than %s", cs, maxUploadCutoff)
	}
	return nil
}

func (f *Fs) setUploadCutoff(cs fs.SizeSuffix) (old fs.SizeSuffix, err error) {
	err = checkUploadCutoff(cs)
	if err == nil {
		old, f.opt.UploadCutoff = f.opt.UploadCutoff, cs
	}
	return
}

// NewFs constructs an Fs from the path, bucket:path
func NewFs(name, root string, m configmap.Mapper) (fs.Fs, error) {
	// Parse config into Options struct
	opt := new(Options)
	err := configstruct.Set(m, opt)
	if err != nil {
		return nil, err
	}
	err = checkUploadChunkSize(opt.ChunkSize)
	if err != nil {
		return nil, errors.Wrap(err, "s3: chunk size")
	}
	err = checkUploadCutoff(opt.UploadCutoff)
	if err != nil {
		return nil, errors.Wrap(err, "s3: upload cutoff")
	}
	bucket, directory, err := s3ParsePath(root)
	if err != nil {
		return nil, err
	}
	if opt.ACL == "" {
		opt.ACL = "private"
	}
	if opt.BucketACL == "" {
		opt.BucketACL = opt.ACL
	}
	c, ses, err := s3Connection(opt)
	if err != nil {
		return nil, err
	}
	f := &Fs{
		name:   name,
		root:   directory,
		opt:    *opt,
		c:      c,
		bucket: bucket,
		ses:    ses,
		pacer:  fs.NewPacer(pacer.NewS3(pacer.MinSleep(minSleep))),
		srv:    fshttp.NewClient(fs.Config),
	}
	f.features = (&fs.Features{
		ReadMimeType:  true,
		WriteMimeType: true,
		BucketBased:   true,
	}).Fill(f)
	if f.root != "" {
		f.root += "/"
		// Check to see if the object exists
		req := s3.HeadObjectInput{
			Bucket: &f.bucket,
			Key:    &directory,
		}
		err = f.pacer.Call(func() (bool, error) {
			_, err = f.c.HeadObject(&req)
			return f.shouldRetry(err)
		})
		if err == nil {
			f.root = path.Dir(directory)
			if f.root == "." {
				f.root = ""
			} else {
				f.root += "/"
			}
			// return an error with an fs which points to the parent
			return f, fs.ErrorIsFile
		}
	}
	// f.listMultipartUploads()
	return f, nil
}

// Return an Object from a path
//
//If it can't be found it returns the error ErrorObjectNotFound.
func (f *Fs) newObjectWithInfo(remote string, info *s3.Object) (fs.Object, error) {
	o := &Object{
		fs:     f,
		remote: remote,
	}
	if info != nil {
		// Set info but not meta
		if info.LastModified == nil {
			fs.Logf(o, "Failed to read last modified")
			o.lastModified = time.Now()
		} else {
			o.lastModified = *info.LastModified
		}
		o.etag = aws.StringValue(info.ETag)
		o.bytes = aws.Int64Value(info.Size)
	} else {
		err := o.readMetaData() // reads info and meta, returning an error
		if err != nil {
			return nil, err
		}
	}
	return o, nil
}

// NewObject finds the Object at remote.  If it can't be found
// it returns the error fs.ErrorObjectNotFound.
func (f *Fs) NewObject(remote string) (fs.Object, error) {
	return f.newObjectWithInfo(remote, nil)
}

// Gets the bucket location
func (f *Fs) getBucketLocation() (string, error) {
	req := s3.GetBucketLocationInput{
		Bucket: &f.bucket,
	}
	var resp *s3.GetBucketLocationOutput
	var err error
	err = f.pacer.Call(func() (bool, error) {
		resp, err = f.c.GetBucketLocation(&req)
		return f.shouldRetry(err)
	})
	if err != nil {
		return "", err
	}
	return s3.NormalizeBucketLocation(aws.StringValue(resp.LocationConstraint)), nil
}

// Updates the region for the bucket by reading the region from the
// bucket then updating the session.
func (f *Fs) updateRegionForBucket() error {
	region, err := f.getBucketLocation()
	if err != nil {
		return errors.Wrap(err, "reading bucket location failed")
	}
	if aws.StringValue(f.c.Config.Endpoint) != "" {
		return errors.Errorf("can't set region to %q as endpoint is set", region)
	}
	if aws.StringValue(f.c.Config.Region) == region {
		return errors.Errorf("region is already %q - not updating", region)
	}

	// Make a new session with the new region
	oldRegion := f.opt.Region
	f.opt.Region = region
	c, ses, err := s3Connection(&f.opt)
	if err != nil {
		return errors.Wrap(err, "creating new session failed")
	}
	f.c = c
	f.ses = ses

	fs.Logf(f, "Switched region to %q from %q", region, oldRegion)
	return nil
}

// listFn is called from list to handle an object.
type listFn func(remote string, object *s3.Object, isDirectory bool) error

// list the objects into the function supplied
//
// dir is the starting directory, "" for root
//
// Set recurse to read sub directories
func (f *Fs) list(dir string, recurse bool, fn listFn) error {
	root := f.root
	if dir != "" {
		root += dir + "/"
	}
	maxKeys := int64(listChunkSize)
	delimiter := ""
	if !recurse {
		delimiter = "/"
	}
	var marker *string
	for {
		// FIXME need to implement ALL loop
		req := s3.ListObjectsInput{
			Bucket:    &f.bucket,
			Delimiter: &delimiter,
			Prefix:    &root,
			MaxKeys:   &maxKeys,
			Marker:    marker,
		}
		var resp *s3.ListObjectsOutput
		var err error
		err = f.pacer.Call(func() (bool, error) {
			resp, err = f.c.ListObjects(&req)
			return f.shouldRetry(err)
		})
		if err != nil {
			if awsErr, ok := err.(awserr.RequestFailure); ok {
				if awsErr.StatusCode() == http.StatusNotFound {
					err = fs.ErrorDirNotFound
				}
			}
			return err
		}
		rootLength := len(f.root)
		if !recurse {
			for _, commonPrefix := range resp.CommonPrefixes {
				if commonPrefix.Prefix == nil {
					fs.Logf(f, "Nil common prefix received")
					continue
				}
				remote := *commonPrefix.Prefix
				if !strings.HasPrefix(remote, f.root) {
					fs.Logf(f, "Odd name received %q", remote)
					continue
				}
				remote = remote[rootLength:]
				if strings.HasSuffix(remote, "/") {
					remote = remote[:len(remote)-1]
				}
				err = fn(remote, &s3.Object{Key: &remote}, true)
				if err != nil {
					return err
				}
			}
		}
		for _, object := range resp.Contents {
			key := aws.StringValue(object.Key)
			if !strings.HasPrefix(key, f.root) {
				fs.Logf(f, "Odd name received %q", key)
				continue
			}
			remote := key[rootLength:]
			// is this a directory marker?
			if (strings.HasSuffix(remote, "/") || remote == "") && *object.Size == 0 {
				if recurse && remote != "" {
					// add a directory in if --fast-list since will have no prefixes
					remote = remote[:len(remote)-1]
					err = fn(remote, &s3.Object{Key: &remote}, true)
					if err != nil {
						return err
					}
				}
				continue // skip directory marker
			}
			err = fn(remote, object, false)
			if err != nil {
				return err
			}
		}
		if !aws.BoolValue(resp.IsTruncated) {
			break
		}
		// Use NextMarker if set, otherwise use last Key
		if resp.NextMarker == nil || *resp.NextMarker == "" {
			if len(resp.Contents) == 0 {
				return errors.New("s3 protocol error: received listing with IsTruncated set, no NextMarker and no Contents")
			}
			marker = resp.Contents[len(resp.Contents)-1].Key
		} else {
			marker = resp.NextMarker
		}
	}
	return nil
}

// Convert a list item into a DirEntry
func (f *Fs) itemToDirEntry(remote string, object *s3.Object, isDirectory bool) (fs.DirEntry, error) {
	if isDirectory {
		size := int64(0)
		if object.Size != nil {
			size = *object.Size
		}
		d := fs.NewDir(remote, time.Time{}).SetSize(size)
		return d, nil
	}
	o, err := f.newObjectWithInfo(remote, object)
	if err != nil {
		return nil, err
	}
	return o, nil
}

// mark the bucket as being OK
func (f *Fs) markBucketOK() {
	if f.bucket != "" {
		f.bucketOKMu.Lock()
		f.bucketOK = true
		f.bucketDeleted = false
		f.bucketOKMu.Unlock()
	}
}

// listDir lists files and directories to out
func (f *Fs) listDir(dir string) (entries fs.DirEntries, err error) {
	// List the objects and directories
	err = f.list(dir, false, func(remote string, object *s3.Object, isDirectory bool) error {
		entry, err := f.itemToDirEntry(remote, object, isDirectory)
		if err != nil {
			return err
		}
		if entry != nil {
			entries = append(entries, entry)
		}
		return nil
	})
	if err != nil {
		return nil, err
	}
	// bucket must be present if listing succeeded
	f.markBucketOK()
	return entries, nil
}

// listBuckets lists the buckets to out
func (f *Fs) listBuckets(dir string) (entries fs.DirEntries, err error) {
	if dir != "" {
		return nil, fs.ErrorListBucketRequired
	}
	req := s3.ListBucketsInput{}
	var resp *s3.ListBucketsOutput
	err = f.pacer.Call(func() (bool, error) {
		resp, err = f.c.ListBuckets(&req)
		return f.shouldRetry(err)
	})
	if err != nil {
		return nil, err
	}
	for _, bucket := range resp.Buckets {
		d := fs.NewDir(aws.StringValue(bucket.Name), aws.TimeValue(bucket.CreationDate))
		entries = append(entries, d)
	}
	return entries, nil
}

// List the objects and directories in dir into entries.  The
// entries can be returned in any order but should be for a
// complete directory.
//
// dir should be "" to list the root, and should not have
// trailing slashes.
//
// This should return ErrDirNotFound if the directory isn't
// found.
func (f *Fs) List(dir string) (entries fs.DirEntries, err error) {
	if f.bucket == "" {
		return f.listBuckets(dir)
	}
	return f.listDir(dir)
}

// ListR lists the objects and directories of the Fs starting
// from dir recursively into out.
//
// dir should be "" to start from the root, and should not
// have trailing slashes.
//
// This should return ErrDirNotFound if the directory isn't
// found.
//
// It should call callback for each tranche of entries read.
// These need not be returned in any particular order.  If
// callback returns an error then the listing will stop
// immediately.
//
// Don't implement this unless you have a more efficient way
// of listing recursively that doing a directory traversal.
func (f *Fs) ListR(dir string, callback fs.ListRCallback) (err error) {
	if f.bucket == "" {
		return fs.ErrorListBucketRequired
	}
	list := walk.NewListRHelper(callback)
	err = f.list(dir, true, func(remote string, object *s3.Object, isDirectory bool) error {
		entry, err := f.itemToDirEntry(remote, object, isDirectory)
		if err != nil {
			return err
		}
		return list.Add(entry)
	})
	if err != nil {
		return err
	}
	// bucket must be present if listing succeeded
	f.markBucketOK()
	return list.Flush()
}

// Put the Object into the bucket
func (f *Fs) Put(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
	// Temporary Object under construction
	fs := &Object{
		fs:     f,
		remote: src.Remote(),
	}
	return fs, fs.Update(in, src, options...)
}

// PutStream uploads to the remote path with the modTime given of indeterminate size
func (f *Fs) PutStream(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) (fs.Object, error) {
	return f.Put(in, src, options...)
}

// Check if the bucket exists
//
// NB this can return incorrect results if called immediately after bucket deletion
func (f *Fs) dirExists() (bool, error) {
	req := s3.HeadBucketInput{
		Bucket: &f.bucket,
	}
	err := f.pacer.Call(func() (bool, error) {
		_, err := f.c.HeadBucket(&req)
		return f.shouldRetry(err)
	})
	if err == nil {
		return true, nil
	}
	if err, ok := err.(awserr.RequestFailure); ok {
		if err.StatusCode() == http.StatusNotFound {
			return false, nil
		}
	}
	return false, err
}

// Mkdir creates the bucket if it doesn't exist
func (f *Fs) Mkdir(dir string) error {
	f.bucketOKMu.Lock()
	defer f.bucketOKMu.Unlock()
	if f.bucketOK {
		return nil
	}
	if !f.bucketDeleted {
		exists, err := f.dirExists()
		if err == nil {
			f.bucketOK = exists
		}
		if err != nil || exists {
			return err
		}
	}
	req := s3.CreateBucketInput{
		Bucket: &f.bucket,
		ACL:    &f.opt.BucketACL,
	}
	if f.opt.LocationConstraint != "" {
		req.CreateBucketConfiguration = &s3.CreateBucketConfiguration{
			LocationConstraint: &f.opt.LocationConstraint,
		}
	}
	err := f.pacer.Call(func() (bool, error) {
		_, err := f.c.CreateBucket(&req)
		return f.shouldRetry(err)
	})
	if err, ok := err.(awserr.Error); ok {
		if err.Code() == "BucketAlreadyOwnedByYou" {
			err = nil
		}
	}
	if err == nil {
		f.bucketOK = true
		f.bucketDeleted = false
		fs.Infof(f, "Bucket created with ACL %q", *req.ACL)
	}
	return err
}

// Rmdir deletes the bucket if the fs is at the root
//
// Returns an error if it isn't empty
func (f *Fs) Rmdir(dir string) error {
	f.bucketOKMu.Lock()
	defer f.bucketOKMu.Unlock()
	if f.root != "" || dir != "" {
		return nil
	}
	req := s3.DeleteBucketInput{
		Bucket: &f.bucket,
	}
	err := f.pacer.Call(func() (bool, error) {
		_, err := f.c.DeleteBucket(&req)
		return f.shouldRetry(err)
	})
	if err == nil {
		f.bucketOK = false
		f.bucketDeleted = true
		fs.Infof(f, "Bucket deleted")
	}
	return err
}

// Precision of the remote
func (f *Fs) Precision() time.Duration {
	return time.Nanosecond
}

// pathEscape escapes s as for a URL path.  It uses rest.URLPathEscape
// but also escapes '+' for S3 and Digital Ocean spaces compatibility
func pathEscape(s string) string {
	return strings.Replace(rest.URLPathEscape(s), "+", "%2B", -1)
}

// Copy src to this remote using server side copy operations.
//
// This is stored with the remote path given
//
// It returns the destination Object and a possible error
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantCopy
func (f *Fs) Copy(src fs.Object, remote string) (fs.Object, error) {
	err := f.Mkdir("")
	if err != nil {
		return nil, err
	}
	srcObj, ok := src.(*Object)
	if !ok {
		fs.Debugf(src, "Can't copy - not same remote type")
		return nil, fs.ErrorCantCopy
	}
	srcFs := srcObj.fs
	key := f.root + remote
	source := pathEscape(srcFs.bucket + "/" + srcFs.root + srcObj.remote)
	req := s3.CopyObjectInput{
		Bucket:            &f.bucket,
		ACL:               &f.opt.ACL,
		Key:               &key,
		CopySource:        &source,
		MetadataDirective: aws.String(s3.MetadataDirectiveCopy),
	}
	if f.opt.ServerSideEncryption != "" {
		req.ServerSideEncryption = &f.opt.ServerSideEncryption
	}
	if f.opt.SSEKMSKeyID != "" {
		req.SSEKMSKeyId = &f.opt.SSEKMSKeyID
	}
	if f.opt.StorageClass != "" {
		req.StorageClass = &f.opt.StorageClass
	}
	err = f.pacer.Call(func() (bool, error) {
		_, err = f.c.CopyObject(&req)
		return f.shouldRetry(err)
	})
	if err != nil {
		return nil, err
	}
	return f.NewObject(remote)
}

// Hashes returns the supported hash sets.
func (f *Fs) Hashes() hash.Set {
	return hash.Set(hash.MD5)
}

// ------------------------------------------------------------

// Fs returns the parent Fs
func (o *Object) Fs() fs.Info {
	return o.fs
}

// Return a string version
func (o *Object) String() string {
	if o == nil {
		return "<nil>"
	}
	return o.remote
}

// Remote returns the remote path
func (o *Object) Remote() string {
	return o.remote
}

var matchMd5 = regexp.MustCompile(`^[0-9a-f]{32}$`)

// Hash returns the Md5sum of an object returning a lowercase hex string
func (o *Object) Hash(t hash.Type) (string, error) {
	if t != hash.MD5 {
		return "", hash.ErrUnsupported
	}
	hash := strings.Trim(strings.ToLower(o.etag), `"`)
	// Check the etag is a valid md5sum
	if !matchMd5.MatchString(hash) {
		err := o.readMetaData()
		if err != nil {
			return "", err
		}

		if md5sum, ok := o.meta[metaMD5Hash]; ok {
			md5sumBytes, err := base64.StdEncoding.DecodeString(*md5sum)
			if err != nil {
				return "", err
			}
			hash = hex.EncodeToString(md5sumBytes)
		} else {
			hash = ""
		}
	}
	return hash, nil
}

// Size returns the size of an object in bytes
func (o *Object) Size() int64 {
	return o.bytes
}

// readMetaData gets the metadata if it hasn't already been fetched
//
// it also sets the info
func (o *Object) readMetaData() (err error) {
	if o.meta != nil {
		return nil
	}
	key := o.fs.root + o.remote
	req := s3.HeadObjectInput{
		Bucket: &o.fs.bucket,
		Key:    &key,
	}
	var resp *s3.HeadObjectOutput
	err = o.fs.pacer.Call(func() (bool, error) {
		var err error
		resp, err = o.fs.c.HeadObject(&req)
		return o.fs.shouldRetry(err)
	})
	if err != nil {
		if awsErr, ok := err.(awserr.RequestFailure); ok {
			if awsErr.StatusCode() == http.StatusNotFound {
				return fs.ErrorObjectNotFound
			}
		}
		return err
	}
	var size int64
	// Ignore missing Content-Length assuming it is 0
	// Some versions of ceph do this due their apache proxies
	if resp.ContentLength != nil {
		size = *resp.ContentLength
	}
	o.etag = aws.StringValue(resp.ETag)
	o.bytes = size
	o.meta = resp.Metadata
	if resp.LastModified == nil {
		fs.Logf(o, "Failed to read last modified from HEAD: %v", err)
		o.lastModified = time.Now()
	} else {
		o.lastModified = *resp.LastModified
	}
	o.mimeType = aws.StringValue(resp.ContentType)
	return nil
}

// ModTime returns the modification time of the object
//
// It attempts to read the objects mtime and if that isn't present the
// LastModified returned in the http headers
func (o *Object) ModTime() time.Time {
	if fs.Config.UseServerModTime {
		return o.lastModified
	}
	err := o.readMetaData()
	if err != nil {
		fs.Logf(o, "Failed to read metadata: %v", err)
		return time.Now()
	}
	// read mtime out of metadata if available
	d, ok := o.meta[metaMtime]
	if !ok || d == nil {
		// fs.Debugf(o, "No metadata")
		return o.lastModified
	}
	modTime, err := swift.FloatStringToTime(*d)
	if err != nil {
		fs.Logf(o, "Failed to read mtime from object: %v", err)
		return o.lastModified
	}
	return modTime
}

// SetModTime sets the modification time of the local fs object
func (o *Object) SetModTime(modTime time.Time) error {
	err := o.readMetaData()
	if err != nil {
		return err
	}
	o.meta[metaMtime] = aws.String(swift.TimeToFloatString(modTime))

	if o.bytes >= maxSizeForCopy {
		fs.Debugf(o, "SetModTime is unsupported for objects bigger than %v bytes", fs.SizeSuffix(maxSizeForCopy))
		return nil
	}

	// Guess the content type
	mimeType := fs.MimeType(o)

	// Copy the object to itself to update the metadata
	key := o.fs.root + o.remote
	sourceKey := o.fs.bucket + "/" + key
	directive := s3.MetadataDirectiveReplace // replace metadata with that passed in
	req := s3.CopyObjectInput{
		Bucket:            &o.fs.bucket,
		ACL:               &o.fs.opt.ACL,
		Key:               &key,
		ContentType:       &mimeType,
		CopySource:        aws.String(pathEscape(sourceKey)),
		Metadata:          o.meta,
		MetadataDirective: &directive,
	}
	if o.fs.opt.ServerSideEncryption != "" {
		req.ServerSideEncryption = &o.fs.opt.ServerSideEncryption
	}
	if o.fs.opt.SSEKMSKeyID != "" {
		req.SSEKMSKeyId = &o.fs.opt.SSEKMSKeyID
	}
	if o.fs.opt.StorageClass != "" {
		req.StorageClass = &o.fs.opt.StorageClass
	}
	err = o.fs.pacer.Call(func() (bool, error) {
		_, err := o.fs.c.CopyObject(&req)
		return o.fs.shouldRetry(err)
	})
	return err
}

// Storable raturns a boolean indicating if this object is storable
func (o *Object) Storable() bool {
	return true
}

// Open an object for read
func (o *Object) Open(options ...fs.OpenOption) (in io.ReadCloser, err error) {
	key := o.fs.root + o.remote
	req := s3.GetObjectInput{
		Bucket: &o.fs.bucket,
		Key:    &key,
	}
	for _, option := range options {
		switch option.(type) {
		case *fs.RangeOption, *fs.SeekOption:
			_, value := option.Header()
			req.Range = &value
		default:
			if option.Mandatory() {
				fs.Logf(o, "Unsupported mandatory option: %v", option)
			}
		}
	}
	var resp *s3.GetObjectOutput
	err = o.fs.pacer.Call(func() (bool, error) {
		var err error
		resp, err = o.fs.c.GetObject(&req)
		return o.fs.shouldRetry(err)
	})
	if err, ok := err.(awserr.RequestFailure); ok {
		if err.Code() == "InvalidObjectState" {
			return nil, errors.Errorf("Object in GLACIER, restore first: %v", key)
		}
	}
	if err != nil {
		return nil, err
	}
	return resp.Body, nil
}

// Update the Object from in with modTime and size
func (o *Object) Update(in io.Reader, src fs.ObjectInfo, options ...fs.OpenOption) error {
	err := o.fs.Mkdir("")
	if err != nil {
		return err
	}
	modTime := src.ModTime()
	size := src.Size()

	multipart := size < 0 || size >= int64(o.fs.opt.UploadCutoff)
	var uploader *s3manager.Uploader
	if multipart {
		uploader = s3manager.NewUploader(o.fs.ses, func(u *s3manager.Uploader) {
			u.Concurrency = o.fs.opt.UploadConcurrency
			u.LeavePartsOnError = false
			u.S3 = o.fs.c
			u.PartSize = int64(o.fs.opt.ChunkSize)

			if size == -1 {
				// Make parts as small as possible while still being able to upload to the
				// S3 file size limit. Rounded up to nearest MB.
				u.PartSize = (((maxFileSize / s3manager.MaxUploadParts) >> 20) + 1) << 20
				return
			}
			// Adjust PartSize until the number of parts is small enough.
			if size/u.PartSize >= s3manager.MaxUploadParts {
				// Calculate partition size rounded up to the nearest MB
				u.PartSize = (((size / s3manager.MaxUploadParts) >> 20) + 1) << 20
			}
		})
	}

	// Set the mtime in the meta data
	metadata := map[string]*string{
		metaMtime: aws.String(swift.TimeToFloatString(modTime)),
	}

	// read the md5sum if available for non multpart and if
	// disable checksum isn't present.
	var md5sum string
	if !multipart || !o.fs.opt.DisableChecksum {
		hash, err := src.Hash(hash.MD5)
		if err == nil && matchMd5.MatchString(hash) {
			hashBytes, err := hex.DecodeString(hash)
			if err == nil {
				md5sum = base64.StdEncoding.EncodeToString(hashBytes)
				if multipart {
					metadata[metaMD5Hash] = &md5sum
				}
			}
		}
	}

	// Guess the content type
	mimeType := fs.MimeType(src)

	key := o.fs.root + o.remote
	if multipart {
		req := s3manager.UploadInput{
			Bucket:      &o.fs.bucket,
			ACL:         &o.fs.opt.ACL,
			Key:         &key,
			Body:        in,
			ContentType: &mimeType,
			Metadata:    metadata,
			//ContentLength: &size,
		}
		if o.fs.opt.ServerSideEncryption != "" {
			req.ServerSideEncryption = &o.fs.opt.ServerSideEncryption
		}
		if o.fs.opt.SSEKMSKeyID != "" {
			req.SSEKMSKeyId = &o.fs.opt.SSEKMSKeyID
		}
		if o.fs.opt.StorageClass != "" {
			req.StorageClass = &o.fs.opt.StorageClass
		}
		err = o.fs.pacer.CallNoRetry(func() (bool, error) {
			_, err = uploader.Upload(&req)
			return o.fs.shouldRetry(err)
		})
		if err != nil {
			return err
		}
	} else {
		req := s3.PutObjectInput{
			Bucket:      &o.fs.bucket,
			ACL:         &o.fs.opt.ACL,
			Key:         &key,
			ContentType: &mimeType,
			Metadata:    metadata,
		}
		if md5sum != "" {
			req.ContentMD5 = &md5sum
		}
		if o.fs.opt.ServerSideEncryption != "" {
			req.ServerSideEncryption = &o.fs.opt.ServerSideEncryption
		}
		if o.fs.opt.SSEKMSKeyID != "" {
			req.SSEKMSKeyId = &o.fs.opt.SSEKMSKeyID
		}
		if o.fs.opt.StorageClass != "" {
			req.StorageClass = &o.fs.opt.StorageClass
		}

		// Create the request
		putObj, _ := o.fs.c.PutObjectRequest(&req)

		// Sign it so we can upload using a presigned request.
		//
		// Note the SDK doesn't currently support streaming to
		// PutObject so we'll use this work-around.
		url, headers, err := putObj.PresignRequest(15 * time.Minute)
		if err != nil {
			return errors.Wrap(err, "s3 upload: sign request")
		}

		// Set request to nil if empty so as not to make chunked encoding
		if size == 0 {
			in = nil
		}

		// create the vanilla http request
		httpReq, err := http.NewRequest("PUT", url, in)
		if err != nil {
			return errors.Wrap(err, "s3 upload: new request")
		}

		// set the headers we signed and the length
		httpReq.Header = headers
		httpReq.ContentLength = size

		err = o.fs.pacer.CallNoRetry(func() (bool, error) {
			resp, err := o.fs.srv.Do(httpReq)
			if err != nil {
				return o.fs.shouldRetry(err)
			}
			body, err := rest.ReadBody(resp)
			if err != nil {
				return o.fs.shouldRetry(err)
			}
			if resp.StatusCode >= 200 && resp.StatusCode < 299 {
				return false, nil
			}
			err = errors.Errorf("s3 upload: %s: %s", resp.Status, body)
			return fserrors.ShouldRetryHTTP(resp, retryErrorCodes), err
		})
		if err != nil {
			return err
		}
	}

	// Read the metadata from the newly created object
	o.meta = nil // wipe old metadata
	err = o.readMetaData()
	return err
}

// Remove an object
func (o *Object) Remove() error {
	key := o.fs.root + o.remote
	req := s3.DeleteObjectInput{
		Bucket: &o.fs.bucket,
		Key:    &key,
	}
	err := o.fs.pacer.Call(func() (bool, error) {
		_, err := o.fs.c.DeleteObject(&req)
		return o.fs.shouldRetry(err)
	})
	return err
}

// MimeType of an Object if known, "" otherwise
func (o *Object) MimeType() string {
	err := o.readMetaData()
	if err != nil {
		fs.Logf(o, "Failed to read metadata: %v", err)
		return ""
	}
	return o.mimeType
}

// Check the interfaces are satisfied
var (
	_ fs.Fs          = &Fs{}
	_ fs.Copier      = &Fs{}
	_ fs.PutStreamer = &Fs{}
	_ fs.ListRer     = &Fs{}
	_ fs.Object      = &Object{}
	_ fs.MimeTyper   = &Object{}
)
