// Code generated by private/model/cli/gen-api/main.go. DO NOT EDIT.

package s3

import (
	"context"
	"fmt"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/internal/awsutil"
	"github.com/aws/aws-sdk-go-v2/private/protocol"
	"github.com/aws/aws-sdk-go-v2/service/s3/internal/arn"
)

type HeadObjectInput struct {
	_ struct{} `type:"structure"`

	// The name of the bucket containing the object.
	//
	// Bucket is a required field
	Bucket *string `location:"uri" locationName:"Bucket" type:"string" required:"true"`

	// Return the object only if its entity tag (ETag) is the same as the one specified,
	// otherwise return a 412 (precondition failed).
	IfMatch *string `location:"header" locationName:"If-Match" type:"string"`

	// Return the object only if it has been modified since the specified time,
	// otherwise return a 304 (not modified).
	IfModifiedSince *time.Time `location:"header" locationName:"If-Modified-Since" type:"timestamp"`

	// Return the object only if its entity tag (ETag) is different from the one
	// specified, otherwise return a 304 (not modified).
	IfNoneMatch *string `location:"header" locationName:"If-None-Match" type:"string"`

	// Return the object only if it has not been modified since the specified time,
	// otherwise return a 412 (precondition failed).
	IfUnmodifiedSince *time.Time `location:"header" locationName:"If-Unmodified-Since" type:"timestamp"`

	// The object key.
	//
	// Key is a required field
	Key *string `location:"uri" locationName:"Key" min:"1" type:"string" required:"true"`

	// Part number of the object being read. This is a positive integer between
	// 1 and 10,000. Effectively performs a 'ranged' HEAD request for the part specified.
	// Useful querying about the size of the part and the number of parts in this
	// object.
	PartNumber *int64 `location:"querystring" locationName:"partNumber" type:"integer"`

	// Downloads the specified range bytes of an object. For more information about
	// the HTTP Range header, see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35.
	//
	// Amazon S3 doesn't support retrieving multiple ranges of data per GET request.
	Range *string `location:"header" locationName:"Range" type:"string"`

	// Confirms that the requester knows that they will be charged for the request.
	// Bucket owners need not specify this parameter in their requests. For information
	// about downloading objects from requester pays buckets, see Downloading Objects
	// in Requestor Pays Buckets (https://docs.aws.amazon.com/AmazonS3/latest/dev/ObjectsinRequesterPaysBuckets.html)
	// in the Amazon S3 Developer Guide.
	RequestPayer RequestPayer `location:"header" locationName:"x-amz-request-payer" type:"string" enum:"true"`

	// Specifies the algorithm to use to when encrypting the object (for example,
	// AES256).
	SSECustomerAlgorithm *string `location:"header" locationName:"x-amz-server-side-encryption-customer-algorithm" type:"string"`

	// Specifies the customer-provided encryption key for Amazon S3 to use in encrypting
	// data. This value is used to store the object and then it is discarded; Amazon
	// S3 does not store the encryption key. The key must be appropriate for use
	// with the algorithm specified in the x-amz-server-side​-encryption​-customer-algorithm
	// header.
	SSECustomerKey *string `location:"header" locationName:"x-amz-server-side-encryption-customer-key" type:"string" sensitive:"true"`

	// Specifies the 128-bit MD5 digest of the encryption key according to RFC 1321.
	// Amazon S3 uses this header for a message integrity check to ensure that the
	// encryption key was transmitted without error.
	SSECustomerKeyMD5 *string `location:"header" locationName:"x-amz-server-side-encryption-customer-key-MD5" type:"string"`

	// VersionId used to reference a specific version of the object.
	VersionId *string `location:"querystring" locationName:"versionId" type:"string"`
}

// String returns the string representation
func (s HeadObjectInput) String() string {
	return awsutil.Prettify(s)
}

// Validate inspects the fields of the type to determine if they are valid.
func (s *HeadObjectInput) Validate() error {
	invalidParams := aws.ErrInvalidParams{Context: "HeadObjectInput"}

	if s.Bucket == nil {
		invalidParams.Add(aws.NewErrParamRequired("Bucket"))
	}

	if s.Key == nil {
		invalidParams.Add(aws.NewErrParamRequired("Key"))
	}
	if s.Key != nil && len(*s.Key) < 1 {
		invalidParams.Add(aws.NewErrParamMinLen("Key", 1))
	}

	if invalidParams.Len() > 0 {
		return invalidParams
	}
	return nil
}

func (s *HeadObjectInput) getBucket() (v string) {
	if s.Bucket == nil {
		return v
	}
	return *s.Bucket
}

func (s *HeadObjectInput) getSSECustomerKey() (v string) {
	if s.SSECustomerKey == nil {
		return v
	}
	return *s.SSECustomerKey
}

// MarshalFields encodes the AWS API shape using the passed in protocol encoder.
func (s HeadObjectInput) MarshalFields(e protocol.FieldEncoder) error {

	if s.IfMatch != nil {
		v := *s.IfMatch

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "If-Match", protocol.StringValue(v), metadata)
	}
	if s.IfModifiedSince != nil {
		v := *s.IfModifiedSince

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "If-Modified-Since",
			protocol.TimeValue{V: v, Format: protocol.RFC822TimeFormatName, QuotedFormatTime: false}, metadata)
	}
	if s.IfNoneMatch != nil {
		v := *s.IfNoneMatch

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "If-None-Match", protocol.StringValue(v), metadata)
	}
	if s.IfUnmodifiedSince != nil {
		v := *s.IfUnmodifiedSince

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "If-Unmodified-Since",
			protocol.TimeValue{V: v, Format: protocol.RFC822TimeFormatName, QuotedFormatTime: false}, metadata)
	}
	if s.Range != nil {
		v := *s.Range

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Range", protocol.StringValue(v), metadata)
	}
	if len(s.RequestPayer) > 0 {
		v := s.RequestPayer

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-request-payer", v, metadata)
	}
	if s.SSECustomerAlgorithm != nil {
		v := *s.SSECustomerAlgorithm

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-server-side-encryption-customer-algorithm", protocol.StringValue(v), metadata)
	}
	if s.SSECustomerKey != nil {
		v := *s.SSECustomerKey

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-server-side-encryption-customer-key", protocol.StringValue(v), metadata)
	}
	if s.SSECustomerKeyMD5 != nil {
		v := *s.SSECustomerKeyMD5

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-server-side-encryption-customer-key-MD5", protocol.StringValue(v), metadata)
	}
	if s.Bucket != nil {
		v := *s.Bucket

		metadata := protocol.Metadata{}
		e.SetValue(protocol.PathTarget, "Bucket", protocol.StringValue(v), metadata)
	}
	if s.Key != nil {
		v := *s.Key

		metadata := protocol.Metadata{}
		e.SetValue(protocol.PathTarget, "Key", protocol.StringValue(v), metadata)
	}
	if s.PartNumber != nil {
		v := *s.PartNumber

		metadata := protocol.Metadata{}
		e.SetValue(protocol.QueryTarget, "partNumber", protocol.Int64Value(v), metadata)
	}
	if s.VersionId != nil {
		v := *s.VersionId

		metadata := protocol.Metadata{}
		e.SetValue(protocol.QueryTarget, "versionId", protocol.StringValue(v), metadata)
	}
	return nil
}

func (s *HeadObjectInput) getEndpointARN() (arn.Resource, error) {
	if s.Bucket == nil {
		return nil, fmt.Errorf("member Bucket is nil")
	}
	return parseEndpointARN(*s.Bucket)
}

func (s *HeadObjectInput) hasEndpointARN() bool {
	if s.Bucket == nil {
		return false
	}
	return arn.IsARN(*s.Bucket)
}

type HeadObjectOutput struct {
	_ struct{} `type:"structure"`

	// Indicates that a range of bytes was specified.
	AcceptRanges *string `location:"header" locationName:"accept-ranges" type:"string"`

	// Specifies caching behavior along the request/reply chain.
	CacheControl *string `location:"header" locationName:"Cache-Control" type:"string"`

	// Specifies presentational information for the object.
	ContentDisposition *string `location:"header" locationName:"Content-Disposition" type:"string"`

	// Specifies what content encodings have been applied to the object and thus
	// what decoding mechanisms must be applied to obtain the media-type referenced
	// by the Content-Type header field.
	ContentEncoding *string `location:"header" locationName:"Content-Encoding" type:"string"`

	// The language the content is in.
	ContentLanguage *string `location:"header" locationName:"Content-Language" type:"string"`

	// Size of the body in bytes.
	ContentLength *int64 `location:"header" locationName:"Content-Length" type:"long"`

	// A standard MIME type describing the format of the object data.
	ContentType *string `location:"header" locationName:"Content-Type" type:"string"`

	// Specifies whether the object retrieved was (true) or was not (false) a Delete
	// Marker. If false, this response header does not appear in the response.
	DeleteMarker *bool `location:"header" locationName:"x-amz-delete-marker" type:"boolean"`

	// An ETag is an opaque identifier assigned by a web server to a specific version
	// of a resource found at a URL.
	ETag *string `location:"header" locationName:"ETag" type:"string"`

	// If the object expiration is configured (see PUT Bucket lifecycle), the response
	// includes this header. It includes the expiry-date and rule-id key-value pairs
	// providing object expiration information. The value of the rule-id is URL
	// encoded.
	Expiration *string `location:"header" locationName:"x-amz-expiration" type:"string"`

	// The date and time at which the object is no longer cacheable.
	Expires *string `location:"header" locationName:"Expires" type:"string"`

	// Last modified date of the object
	LastModified *time.Time `location:"header" locationName:"Last-Modified" type:"timestamp"`

	// A map of metadata to store with the object in S3.
	Metadata map[string]string `location:"headers" locationName:"x-amz-meta-" type:"map"`

	// This is set to the number of metadata entries not returned in x-amz-meta
	// headers. This can happen if you create metadata using an API like SOAP that
	// supports more flexible metadata than the REST API. For example, using SOAP,
	// you can create metadata whose values are not legal HTTP headers.
	MissingMeta *int64 `location:"header" locationName:"x-amz-missing-meta" type:"integer"`

	// Specifies whether a legal hold is in effect for this object. This header
	// is only returned if the requester has the s3:GetObjectLegalHold permission.
	// This header is not returned if the specified version of this object has never
	// had a legal hold applied. For more information about S3 Object Lock, see
	// Object Lock (https://docs.aws.amazon.com/AmazonS3/latest/dev/object-lock.html).
	ObjectLockLegalHoldStatus ObjectLockLegalHoldStatus `location:"header" locationName:"x-amz-object-lock-legal-hold" type:"string" enum:"true"`

	// The Object Lock mode, if any, that's in effect for this object. This header
	// is only returned if the requester has the s3:GetObjectRetention permission.
	// For more information about S3 Object Lock, see Object Lock (https://docs.aws.amazon.com/AmazonS3/latest/dev/object-lock.html).
	ObjectLockMode ObjectLockMode `location:"header" locationName:"x-amz-object-lock-mode" type:"string" enum:"true"`

	// The date and time when the Object Lock retention period expires. This header
	// is only returned if the requester has the s3:GetObjectRetention permission.
	ObjectLockRetainUntilDate *time.Time `location:"header" locationName:"x-amz-object-lock-retain-until-date" type:"timestamp" timestampFormat:"iso8601"`

	// The count of parts this object has.
	PartsCount *int64 `location:"header" locationName:"x-amz-mp-parts-count" type:"integer"`

	// Amazon S3 can return this header if your request involves a bucket that is
	// either a source or destination in a replication rule.
	//
	// In replication, you have a source bucket on which you configure replication
	// and destination bucket where Amazon S3 stores object replicas. When you request
	// an object (GetObject) or object metadata (HeadObject) from these buckets,
	// Amazon S3 will return the x-amz-replication-status header in the response
	// as follows:
	//
	//    * If requesting an object from the source bucket — Amazon S3 will return
	//    the x-amz-replication-status header if the object in your request is eligible
	//    for replication. For example, suppose that in your replication configuration,
	//    you specify object prefix TaxDocs requesting Amazon S3 to replicate objects
	//    with key prefix TaxDocs. Any objects you upload with this key name prefix,
	//    for example TaxDocs/document1.pdf, are eligible for replication. For any
	//    object request with this key name prefix, Amazon S3 will return the x-amz-replication-status
	//    header with value PENDING, COMPLETED or FAILED indicating object replication
	//    status.
	//
	//    * If requesting an object from the destination bucket — Amazon S3 will
	//    return the x-amz-replication-status header with value REPLICA if the object
	//    in your request is a replica that Amazon S3 created.
	//
	// For more information, see Replication (https://docs.aws.amazon.com/AmazonS3/latest/dev/NotificationHowTo.html).
	ReplicationStatus ReplicationStatus `location:"header" locationName:"x-amz-replication-status" type:"string" enum:"true"`

	// If present, indicates that the requester was successfully charged for the
	// request.
	RequestCharged RequestCharged `location:"header" locationName:"x-amz-request-charged" type:"string" enum:"true"`

	// If the object is an archived object (an object whose storage class is GLACIER),
	// the response includes this header if either the archive restoration is in
	// progress (see RestoreObject or an archive copy is already restored.
	//
	// If an archive copy is already restored, the header value indicates when Amazon
	// S3 is scheduled to delete the object copy. For example:
	//
	// x-amz-restore: ongoing-request="false", expiry-date="Fri, 23 Dec 2012 00:00:00
	// GMT"
	//
	// If the object restoration is in progress, the header returns the value ongoing-request="true".
	//
	// For more information about archiving objects, see Transitioning Objects:
	// General Considerations (https://docs.aws.amazon.com/AmazonS3/latest/dev/object-lifecycle-mgmt.html#lifecycle-transition-general-considerations).
	Restore *string `location:"header" locationName:"x-amz-restore" type:"string"`

	// If server-side encryption with a customer-provided encryption key was requested,
	// the response will include this header confirming the encryption algorithm
	// used.
	SSECustomerAlgorithm *string `location:"header" locationName:"x-amz-server-side-encryption-customer-algorithm" type:"string"`

	// If server-side encryption with a customer-provided encryption key was requested,
	// the response will include this header to provide round-trip message integrity
	// verification of the customer-provided encryption key.
	SSECustomerKeyMD5 *string `location:"header" locationName:"x-amz-server-side-encryption-customer-key-MD5" type:"string"`

	// If present, specifies the ID of the AWS Key Management Service (AWS KMS)
	// symmetric customer managed customer master key (CMK) that was used for the
	// object.
	SSEKMSKeyId *string `location:"header" locationName:"x-amz-server-side-encryption-aws-kms-key-id" type:"string" sensitive:"true"`

	// If the object is stored using server-side encryption either with an AWS KMS
	// customer master key (CMK) or an Amazon S3-managed encryption key, the response
	// includes this header with the value of the server-side encryption algorithm
	// used when storing this object in Amazon S3 (for example, AES256, aws:kms).
	ServerSideEncryption ServerSideEncryption `location:"header" locationName:"x-amz-server-side-encryption" type:"string" enum:"true"`

	// Provides storage class information of the object. Amazon S3 returns this
	// header for all objects except for S3 Standard storage class objects.
	//
	// For more information, see Storage Classes (https://docs.aws.amazon.com/AmazonS3/latest/dev/storage-class-intro.html).
	StorageClass StorageClass `location:"header" locationName:"x-amz-storage-class" type:"string" enum:"true"`

	// Version of the object.
	VersionId *string `location:"header" locationName:"x-amz-version-id" type:"string"`

	// If the bucket is configured as a website, redirects requests for this object
	// to another object in the same bucket or to an external URL. Amazon S3 stores
	// the value of this header in the object metadata.
	WebsiteRedirectLocation *string `location:"header" locationName:"x-amz-website-redirect-location" type:"string"`
}

// String returns the string representation
func (s HeadObjectOutput) String() string {
	return awsutil.Prettify(s)
}

// MarshalFields encodes the AWS API shape using the passed in protocol encoder.
func (s HeadObjectOutput) MarshalFields(e protocol.FieldEncoder) error {
	if s.AcceptRanges != nil {
		v := *s.AcceptRanges

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "accept-ranges", protocol.StringValue(v), metadata)
	}
	if s.CacheControl != nil {
		v := *s.CacheControl

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Cache-Control", protocol.StringValue(v), metadata)
	}
	if s.ContentDisposition != nil {
		v := *s.ContentDisposition

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Content-Disposition", protocol.StringValue(v), metadata)
	}
	if s.ContentEncoding != nil {
		v := *s.ContentEncoding

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Content-Encoding", protocol.StringValue(v), metadata)
	}
	if s.ContentLanguage != nil {
		v := *s.ContentLanguage

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Content-Language", protocol.StringValue(v), metadata)
	}
	if s.ContentLength != nil {
		v := *s.ContentLength

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Content-Length", protocol.Int64Value(v), metadata)
	}
	if s.ContentType != nil {
		v := *s.ContentType

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Content-Type", protocol.StringValue(v), metadata)
	}
	if s.DeleteMarker != nil {
		v := *s.DeleteMarker

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-delete-marker", protocol.BoolValue(v), metadata)
	}
	if s.ETag != nil {
		v := *s.ETag

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "ETag", protocol.StringValue(v), metadata)
	}
	if s.Expiration != nil {
		v := *s.Expiration

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-expiration", protocol.StringValue(v), metadata)
	}
	if s.Expires != nil {
		v := *s.Expires

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Expires", protocol.StringValue(v), metadata)
	}
	if s.LastModified != nil {
		v := *s.LastModified

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "Last-Modified",
			protocol.TimeValue{V: v, Format: protocol.RFC822TimeFormatName, QuotedFormatTime: false}, metadata)
	}
	if s.MissingMeta != nil {
		v := *s.MissingMeta

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-missing-meta", protocol.Int64Value(v), metadata)
	}
	if len(s.ObjectLockLegalHoldStatus) > 0 {
		v := s.ObjectLockLegalHoldStatus

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-object-lock-legal-hold", v, metadata)
	}
	if len(s.ObjectLockMode) > 0 {
		v := s.ObjectLockMode

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-object-lock-mode", v, metadata)
	}
	if s.ObjectLockRetainUntilDate != nil {
		v := *s.ObjectLockRetainUntilDate

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-object-lock-retain-until-date",
			protocol.TimeValue{V: v, Format: "iso8601", QuotedFormatTime: false}, metadata)
	}
	if s.PartsCount != nil {
		v := *s.PartsCount

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-mp-parts-count", protocol.Int64Value(v), metadata)
	}
	if len(s.ReplicationStatus) > 0 {
		v := s.ReplicationStatus

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-replication-status", v, metadata)
	}
	if len(s.RequestCharged) > 0 {
		v := s.RequestCharged

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-request-charged", v, metadata)
	}
	if s.Restore != nil {
		v := *s.Restore

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-restore", protocol.StringValue(v), metadata)
	}
	if s.SSECustomerAlgorithm != nil {
		v := *s.SSECustomerAlgorithm

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-server-side-encryption-customer-algorithm", protocol.StringValue(v), metadata)
	}
	if s.SSECustomerKeyMD5 != nil {
		v := *s.SSECustomerKeyMD5

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-server-side-encryption-customer-key-MD5", protocol.StringValue(v), metadata)
	}
	if s.SSEKMSKeyId != nil {
		v := *s.SSEKMSKeyId

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-server-side-encryption-aws-kms-key-id", protocol.StringValue(v), metadata)
	}
	if len(s.ServerSideEncryption) > 0 {
		v := s.ServerSideEncryption

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-server-side-encryption", v, metadata)
	}
	if len(s.StorageClass) > 0 {
		v := s.StorageClass

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-storage-class", v, metadata)
	}
	if s.VersionId != nil {
		v := *s.VersionId

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-version-id", protocol.StringValue(v), metadata)
	}
	if s.WebsiteRedirectLocation != nil {
		v := *s.WebsiteRedirectLocation

		metadata := protocol.Metadata{}
		e.SetValue(protocol.HeaderTarget, "x-amz-website-redirect-location", protocol.StringValue(v), metadata)
	}
	if s.Metadata != nil {
		v := s.Metadata

		metadata := protocol.Metadata{}
		ms0 := e.Map(protocol.HeadersTarget, "x-amz-meta-", metadata)
		ms0.Start()
		for k1, v1 := range v {
			ms0.MapSetValue(k1, protocol.StringValue(v1))
		}
		ms0.End()

	}
	return nil
}

const opHeadObject = "HeadObject"

// HeadObjectRequest returns a request value for making API operation for
// Amazon Simple Storage Service.
//
// The HEAD operation retrieves metadata from an object without returning the
// object itself. This operation is useful if you're only interested in an object's
// metadata. To use HEAD, you must have READ access to the object.
//
// A HEAD request has the same options as a GET operation on an object. The
// response is identical to the GET response except that there is no response
// body.
//
// If you encrypt an object by using server-side encryption with customer-provided
// encryption keys (SSE-C) when you store the object in Amazon S3, then when
// you retrieve the metadata from the object, you must use the following headers:
//
//    * x-amz-server-side​-encryption​-customer-algorithm
//
//    * x-amz-server-side​-encryption​-customer-key
//
//    * x-amz-server-side​-encryption​-customer-key-MD5
//
// For more information about SSE-C, see Server-Side Encryption (Using Customer-Provided
// Encryption Keys) (https://docs.aws.amazon.com/AmazonS3/latest/dev/ServerSideEncryptionCustomerKeys.html).
//
// Encryption request headers, like x-amz-server-side-encryption, should not
// be sent for GET requests if your object uses server-side encryption with
// CMKs stored in AWS KMS (SSE-KMS) or server-side encryption with Amazon S3–managed
// encryption keys (SSE-S3). If your object does use these types of keys, you’ll
// get an HTTP 400 BadRequest error.
//
// Request headers are limited to 8 KB in size. For more information, see Common
// Request Headers (https://docs.aws.amazon.com/AmazonS3/latest/API/RESTCommonRequestHeaders.html).
//
// Consider the following when using request headers:
//
//    * Consideration 1 – If both of the If-Match and If-Unmodified-Since
//    headers are present in the request as follows: If-Match condition evaluates
//    to true, and; If-Unmodified-Since condition evaluates to false; Then Amazon
//    S3 returns 200 OK and the data requested.
//
//    * Consideration 2 – If both of the If-None-Match and If-Modified-Since
//    headers are present in the request as follows: If-None-Match condition
//    evaluates to false, and; If-Modified-Since condition evaluates to true;
//    Then Amazon S3 returns the 304 Not Modified response code.
//
// For more information about conditional requests, see RFC 7232 (https://tools.ietf.org/html/rfc7232).
//
// Permissions
//
// You need the s3:GetObject permission for this operation. For more information,
// see Specifying Permissions in a Policy (https://docs.aws.amazon.com/AmazonS3/latest/dev/using-with-s3-actions.html).
// If the object you request does not exist, the error Amazon S3 returns depends
// on whether you also have the s3:ListBucket permission.
//
//    * If you have the s3:ListBucket permission on the bucket, Amazon S3 returns
//    an HTTP status code 404 ("no such key") error.
//
//    * If you don’t have the s3:ListBucket permission, Amazon S3 returns
//    an HTTP status code 403 ("access denied") error.
//
// The following operation is related to HeadObject:
//
//    * GetObject
//
// See http://docs.aws.amazon.com/AmazonS3/latest/API/ErrorResponses.html#RESTErrorResponses
// for more information on returned errors.
//
//    // Example sending a request using HeadObjectRequest.
//    req := client.HeadObjectRequest(params)
//    resp, err := req.Send(context.TODO())
//    if err == nil {
//        fmt.Println(resp)
//    }
//
// Please also see https://docs.aws.amazon.com/goto/WebAPI/s3-2006-03-01/HeadObject
func (c *Client) HeadObjectRequest(input *HeadObjectInput) HeadObjectRequest {
	op := &aws.Operation{
		Name:       opHeadObject,
		HTTPMethod: "HEAD",
		HTTPPath:   "/{Bucket}/{Key+}",
	}

	if input == nil {
		input = &HeadObjectInput{}
	}

	req := c.newRequest(op, input, &HeadObjectOutput{})

	return HeadObjectRequest{Request: req, Input: input, Copy: c.HeadObjectRequest}
}

// HeadObjectRequest is the request type for the
// HeadObject API operation.
type HeadObjectRequest struct {
	*aws.Request
	Input *HeadObjectInput
	Copy  func(*HeadObjectInput) HeadObjectRequest
}

// Send marshals and sends the HeadObject API request.
func (r HeadObjectRequest) Send(ctx context.Context) (*HeadObjectResponse, error) {
	r.Request.SetContext(ctx)
	err := r.Request.Send()
	if err != nil {
		return nil, err
	}

	resp := &HeadObjectResponse{
		HeadObjectOutput: r.Request.Data.(*HeadObjectOutput),
		response:         &aws.Response{Request: r.Request},
	}

	return resp, nil
}

// HeadObjectResponse is the response type for the
// HeadObject API operation.
type HeadObjectResponse struct {
	*HeadObjectOutput

	response *aws.Response
}

// SDKResponseMetdata returns the response metadata for the
// HeadObject request.
func (r *HeadObjectResponse) SDKResponseMetdata() *aws.Response {
	return r.response
}