Source File
	api_op_HeadObject.go

Belonging Package
	github.com/aws/aws-sdk-go-v2/service/s3

// Code generated by smithy-go-codegen DO NOT EDIT.

package s3

import (
	"context"
	"errors"
	"fmt"
	awsmiddleware "github.com/aws/aws-sdk-go-v2/aws/middleware"
	"github.com/aws/aws-sdk-go-v2/aws/signer/v4"
	s3cust "github.com/aws/aws-sdk-go-v2/service/s3/internal/customizations"
	"github.com/aws/aws-sdk-go-v2/service/s3/types"
	smithy "github.com/aws/smithy-go"
	"github.com/aws/smithy-go/middleware"
	smithytime "github.com/aws/smithy-go/time"
	smithyhttp "github.com/aws/smithy-go/transport/http"
	smithywaiter "github.com/aws/smithy-go/waiter"
	"time"
)

// The HEAD action retrieves metadata from an object without returning the object
// itself. This action 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 action on an object. The response is identical to the GET
// response except that there is no response body. Because of this, if the HEAD
// request generates an error, it returns a generic 404 Not Found or 403 Forbidden
// code. It is not possible to retrieve the exact exception beyond these error
// codes. 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 KMS keys
// (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.
//
// * The last modified property in this case is the creation
// date of the object.
//
// 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 relevant read
// object (or version) 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 actions are related to HeadObject:
//
// * GetObject
// (https://docs.aws.amazon.com/AmazonS3/latest/API/API_GetObject.html)
//
// *
// GetObjectAttributes
// (https://docs.aws.amazon.com/AmazonS3/latest/API/API_GetObjectAttributes.html)
func (c *Client) HeadObject(ctx context.Context, params *HeadObjectInput, optFns ...func(*Options)) (*HeadObjectOutput, error) {
	if params == nil {
		params = &HeadObjectInput{}
	}

	result, metadata, err := c.invokeOperation(ctx, "HeadObject", params, optFns, c.addOperationHeadObjectMiddlewares)
	if err != nil {
		return nil, err
	}

	out := result.(*HeadObjectOutput)
	out.ResultMetadata = metadata
	return out, nil
}

type HeadObjectInput struct {

	// The name of the bucket containing the object. When using this action with an
	// access point, you must direct requests to the access point hostname. The access
	// point hostname takes the form
	// AccessPointName-AccountId.s3-accesspoint.Region.amazonaws.com. When using this
	// action with an access point through the Amazon Web Services SDKs, you provide
	// the access point ARN in place of the bucket name. For more information about
	// access point ARNs, see Using access points
	// (https://docs.aws.amazon.com/AmazonS3/latest/userguide/using-access-points.html)
	// in the Amazon S3 User Guide. When using this action with Amazon S3 on Outposts,
	// you must direct requests to the S3 on Outposts hostname. The S3 on Outposts
	// hostname takes the form
	// AccessPointName-AccountId.outpostID.s3-outposts.Region.amazonaws.com. When using
	// this action with S3 on Outposts through the Amazon Web Services SDKs, you
	// provide the Outposts bucket ARN in place of the bucket name. For more
	// information about S3 on Outposts ARNs, see Using Amazon S3 on Outposts
	// (https://docs.aws.amazon.com/AmazonS3/latest/userguide/S3onOutposts.html) in the
	// Amazon S3 User Guide.
	//
	// This member is required.
	Bucket *string

	// The object key.
	//
	// This member is required.
	Key *string

	// To retrieve the checksum, this parameter must be enabled. In addition, if you
	// enable ChecksumMode and the object is encrypted with Amazon Web Services Key
	// Management Service (Amazon Web Services KMS), you must have permission to use
	// the kms:Decrypt action for the request to succeed.
	ChecksumMode types.ChecksumMode

	// The account ID of the expected bucket owner. If the bucket is owned by a
	// different account, the request fails with the HTTP status code 403 Forbidden
	// (access denied).
	ExpectedBucketOwner *string

	// Return the object only if its entity tag (ETag) is the same as the one
	// specified; otherwise, return a 412 (precondition failed) error.
	IfMatch *string

	// Return the object only if it has been modified since the specified time;
	// otherwise, return a 304 (not modified) error.
	IfModifiedSince *time.Time

	// Return the object only if its entity tag (ETag) is different from the one
	// specified; otherwise, return a 304 (not modified) error.
	IfNoneMatch *string

	// Return the object only if it has not been modified since the specified time;
	// otherwise, return a 412 (precondition failed) error.
	IfUnmodifiedSince *time.Time

	// 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 int32

	// Because HeadObject returns only the metadata for an object, this parameter has
	// no effect.
	Range *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 Requester Pays Buckets
	// (https://docs.aws.amazon.com/AmazonS3/latest/dev/ObjectsinRequesterPaysBuckets.html)
	// in the Amazon S3 User Guide.
	RequestPayer types.RequestPayer

	// Specifies the algorithm to use to when encrypting the object (for example,
	// AES256).
	SSECustomerAlgorithm *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

	// 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

	// VersionId used to reference a specific version of the object.
	VersionId *string

	noSmithyDocumentSerde
}

type HeadObjectOutput struct {

	// Indicates that a range of bytes was specified.
	AcceptRanges *string

	// The archive state of the head object.
	ArchiveStatus types.ArchiveStatus

	// Indicates whether the object uses an S3 Bucket Key for server-side encryption
	// with Amazon Web Services KMS (SSE-KMS).
	BucketKeyEnabled bool

	// Specifies caching behavior along the request/reply chain.
	CacheControl *string

	// The base64-encoded, 32-bit CRC32 checksum of the object. This will only be
	// present if it was uploaded with the object. With multipart uploads, this may not
	// be a checksum value of the object. For more information about how checksums are
	// calculated with multipart uploads, see  Checking object integrity
	// (https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html#large-object-checksums)
	// in the Amazon S3 User Guide.
	ChecksumCRC32 *string

	// The base64-encoded, 32-bit CRC32C checksum of the object. This will only be
	// present if it was uploaded with the object. With multipart uploads, this may not
	// be a checksum value of the object. For more information about how checksums are
	// calculated with multipart uploads, see  Checking object integrity
	// (https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html#large-object-checksums)
	// in the Amazon S3 User Guide.
	ChecksumCRC32C *string

	// The base64-encoded, 160-bit SHA-1 digest of the object. This will only be
	// present if it was uploaded with the object. With multipart uploads, this may not
	// be a checksum value of the object. For more information about how checksums are
	// calculated with multipart uploads, see  Checking object integrity
	// (https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html#large-object-checksums)
	// in the Amazon S3 User Guide.
	ChecksumSHA1 *string

	// The base64-encoded, 256-bit SHA-256 digest of the object. This will only be
	// present if it was uploaded with the object. With multipart uploads, this may not
	// be a checksum value of the object. For more information about how checksums are
	// calculated with multipart uploads, see  Checking object integrity
	// (https://docs.aws.amazon.com/AmazonS3/latest/userguide/checking-object-integrity.html#large-object-checksums)
	// in the Amazon S3 User Guide.
	ChecksumSHA256 *string

	// Specifies presentational information for the object.
	ContentDisposition *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

	// The language the content is in.
	ContentLanguage *string

	// Size of the body in bytes.
	ContentLength int64

	// A standard MIME type describing the format of the object data.
	ContentType *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

	// An entity tag (ETag) is an opaque identifier assigned by a web server to a
	// specific version of a resource found at a URL.
	ETag *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

	// The date and time at which the object is no longer cacheable.
	Expires *time.Time

	// Creation date of the object.
	LastModified *time.Time

	// A map of metadata to store with the object in S3.
	//
	// Map keys will be normalized to lower-case.
	Metadata map[string]string

	// 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 int32

	// 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 types.ObjectLockLegalHoldStatus

	// 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 types.ObjectLockMode

	// 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

	// The count of parts this object has. This value is only returned if you specify
	// partNumber in your request and the object was uploaded as a multipart upload.
	PartsCount int32

	// Amazon S3 can return this header if your request involves a bucket that is
	// either a source or a destination in a replication rule. In replication, you have
	// a source bucket on which you configure replication and destination bucket or
	// buckets 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 a 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 and there is no replica modification
	// replication in progress.
	//
	// * When replicating objects to multiple destination
	// buckets, the x-amz-replication-status header acts differently. The header of the
	// source object will only return a value of COMPLETED when replication is
	// successful to all destinations. The header will remain at value PENDING until
	// replication has completed for all destinations. If one or more destinations
	// fails replication the header will return FAILED.
	//
	// For more information, see
	// Replication
	// (https://docs.aws.amazon.com/AmazonS3/latest/dev/NotificationHowTo.html).
	ReplicationStatus types.ReplicationStatus

	// If present, indicates that the requester was successfully charged for the
	// request.
	RequestCharged types.RequestCharged

	// 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
	// (https://docs.aws.amazon.com/AmazonS3/latest/API/API_RestoreObject.html) 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, 21 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

	// 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

	// 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

	// If present, specifies the ID of the Amazon Web Services Key Management Service
	// (Amazon Web Services KMS) symmetric customer managed key that was used for the
	// object.
	SSEKMSKeyId *string

	// If the object is stored using server-side encryption either with an Amazon Web
	// Services KMS key 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 types.ServerSideEncryption

	// 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 types.StorageClass

	// Version of the object.
	VersionId *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

	// Metadata pertaining to the operation's result.
	ResultMetadata middleware.Metadata

	noSmithyDocumentSerde
}

func (c *Client) addOperationHeadObjectMiddlewares(stack *middleware.Stack, options Options) (err error) {
	err = stack.Serialize.Add(&awsRestxml_serializeOpHeadObject{}, middleware.After)
	if err != nil {
		return err
	}
	err = stack.Deserialize.Add(&awsRestxml_deserializeOpHeadObject{}, middleware.After)
	if err != nil {
		return err
	}
	if err = addSetLoggerMiddleware(stack, options); err != nil {
		return err
	}
	if err = awsmiddleware.AddClientRequestIDMiddleware(stack); err != nil {
		return err
	}
	if err = smithyhttp.AddComputeContentLengthMiddleware(stack); err != nil {
		return err
	}
	if err = addResolveEndpointMiddleware(stack, options); err != nil {
		return err
	}
	if err = v4.AddComputePayloadSHA256Middleware(stack); err != nil {
		return err
	}
	if err = addRetryMiddlewares(stack, options); err != nil {
		return err
	}
	if err = addHTTPSignerV4Middleware(stack, options); err != nil {
		return err
	}
	if err = awsmiddleware.AddRawResponseToMetadata(stack); err != nil {
		return err
	}
	if err = awsmiddleware.AddRecordResponseTiming(stack); err != nil {
		return err
	}
	if err = addClientUserAgent(stack); err != nil {
		return err
	}
	if err = smithyhttp.AddErrorCloseResponseBodyMiddleware(stack); err != nil {
		return err
	}
	if err = smithyhttp.AddCloseResponseBodyMiddleware(stack); err != nil {
		return err
	}
	if err = swapWithCustomHTTPSignerMiddleware(stack, options); err != nil {
		return err
	}
	if err = addOpHeadObjectValidationMiddleware(stack); err != nil {
		return err
	}
	if err = stack.Initialize.Add(newServiceMetadataMiddleware_opHeadObject(options.Region), middleware.Before); err != nil {
		return err
	}
	if err = addMetadataRetrieverMiddleware(stack); err != nil {
		return err
	}
	if err = addHeadObjectUpdateEndpoint(stack, options); err != nil {
		return err
	}
	if err = addResponseErrorMiddleware(stack); err != nil {
		return err
	}
	if err = v4.AddContentSHA256HeaderMiddleware(stack); err != nil {
		return err
	}
	if err = disableAcceptEncodingGzip(stack); err != nil {
		return err
	}
	if err = addRequestResponseLogging(stack, options); err != nil {
		return err
	}
	return nil
}

// HeadObjectAPIClient is a client that implements the HeadObject operation.
type HeadObjectAPIClient interface {
	HeadObject(context.Context, *HeadObjectInput, ...func(*Options)) (*HeadObjectOutput, error)
}

var _ HeadObjectAPIClient = (*Client)(nil)

// ObjectExistsWaiterOptions are waiter options for ObjectExistsWaiter
type ObjectExistsWaiterOptions struct {

	// Set of options to modify how an operation is invoked. These apply to all
	// operations invoked for this client. Use functional options on operation call to
	// modify this list for per operation behavior.
	APIOptions []func(*middleware.Stack) error

	// MinDelay is the minimum amount of time to delay between retries. If unset,
	// ObjectExistsWaiter will use default minimum delay of 5 seconds. Note that
	// MinDelay must resolve to a value lesser than or equal to the MaxDelay.
	MinDelay time.Duration

	// MaxDelay is the maximum amount of time to delay between retries. If unset or set
	// to zero, ObjectExistsWaiter will use default max delay of 120 seconds. Note that
	// MaxDelay must resolve to value greater than or equal to the MinDelay.
	MaxDelay time.Duration

	// LogWaitAttempts is used to enable logging for waiter retry attempts
	LogWaitAttempts bool

	// Retryable is function that can be used to override the service defined
	// waiter-behavior based on operation output, or returned error. This function is
	// used by the waiter to decide if a state is retryable or a terminal state. By
	// default service-modeled logic will populate this option. This option can thus be
	// used to define a custom waiter state with fall-back to service-modeled waiter
	// state mutators.The function returns an error in case of a failure state. In case
	// of retry state, this function returns a bool value of true and nil error, while
	// in case of success it returns a bool value of false and nil error.
	Retryable func(context.Context, *HeadObjectInput, *HeadObjectOutput, error) (bool, error)
}

// ObjectExistsWaiter defines the waiters for ObjectExists
type ObjectExistsWaiter struct {
	client HeadObjectAPIClient

	options ObjectExistsWaiterOptions
}

// NewObjectExistsWaiter constructs a ObjectExistsWaiter.
func NewObjectExistsWaiter(client HeadObjectAPIClient, optFns ...func(*ObjectExistsWaiterOptions)) *ObjectExistsWaiter {
	options := ObjectExistsWaiterOptions{}
	options.MinDelay = 5 * time.Second
	options.MaxDelay = 120 * time.Second
	options.Retryable = objectExistsStateRetryable

	for _, fn := range optFns {
		fn(&options)
	}
	return &ObjectExistsWaiter{
		client:  client,
		options: options,
	}
}

// Wait calls the waiter function for ObjectExists waiter. The maxWaitDur is the
// maximum wait duration the waiter will wait. The maxWaitDur is required and must
// be greater than zero.
func (w *ObjectExistsWaiter) Wait(ctx context.Context, params *HeadObjectInput, maxWaitDur time.Duration, optFns ...func(*ObjectExistsWaiterOptions)) error {
	_, err := w.WaitForOutput(ctx, params, maxWaitDur, optFns...)
	return err
}

// WaitForOutput calls the waiter function for ObjectExists waiter and returns the
// output of the successful operation. The maxWaitDur is the maximum wait duration
// the waiter will wait. The maxWaitDur is required and must be greater than zero.
func (w *ObjectExistsWaiter) WaitForOutput(ctx context.Context, params *HeadObjectInput, maxWaitDur time.Duration, optFns ...func(*ObjectExistsWaiterOptions)) (*HeadObjectOutput, error) {
	if maxWaitDur <= 0 {
		return nil, fmt.Errorf("maximum wait time for waiter must be greater than zero")
	}

	options := w.options
	for _, fn := range optFns {
		fn(&options)
	}

	if options.MaxDelay <= 0 {
		options.MaxDelay = 120 * time.Second
	}

	if options.MinDelay > options.MaxDelay {
		return nil, fmt.Errorf("minimum waiter delay %v must be lesser than or equal to maximum waiter delay of %v.", options.MinDelay, options.MaxDelay)
	}

	ctx, cancelFn := context.WithTimeout(ctx, maxWaitDur)
	defer cancelFn()

	logger := smithywaiter.Logger{}
	remainingTime := maxWaitDur

	var attempt int64
	for {

		attempt++
		apiOptions := options.APIOptions
		start := time.Now()

		if options.LogWaitAttempts {
			logger.Attempt = attempt
			apiOptions = append([]func(*middleware.Stack) error{}, options.APIOptions...)
			apiOptions = append(apiOptions, logger.AddLogger)
		}

		out, err := w.client.HeadObject(ctx, params, func(o *Options) {
			o.APIOptions = append(o.APIOptions, apiOptions...)
		})

		retryable, err := options.Retryable(ctx, params, out, err)
		if err != nil {
			return nil, err
		}
		if !retryable {
			return out, nil
		}

		remainingTime -= time.Since(start)
		if remainingTime < options.MinDelay || remainingTime <= 0 {
			break
		}

		// compute exponential backoff between waiter retries
		delay, err := smithywaiter.ComputeDelay(
			attempt, options.MinDelay, options.MaxDelay, remainingTime,
		)
		if err != nil {
			return nil, fmt.Errorf("error computing waiter delay, %w", err)
		}

		remainingTime -= delay
		// sleep for the delay amount before invoking a request
		if err := smithytime.SleepWithContext(ctx, delay); err != nil {
			return nil, fmt.Errorf("request cancelled while waiting, %w", err)
		}
	}
	return nil, fmt.Errorf("exceeded max wait time for ObjectExists waiter")
}

func objectExistsStateRetryable(ctx context.Context, input *HeadObjectInput, output *HeadObjectOutput, err error) (bool, error) {

	if err == nil {
		return false, nil
	}

	if err != nil {
		var apiErr smithy.APIError
		ok := errors.As(err, &apiErr)
		if !ok {
			return false, fmt.Errorf("expected err to be of type smithy.APIError, got %w", err)
		}

		if "NotFound" == apiErr.ErrorCode() {
			return true, nil
		}
	}

	return true, nil
}

// ObjectNotExistsWaiterOptions are waiter options for ObjectNotExistsWaiter
type ObjectNotExistsWaiterOptions struct {

	// Set of options to modify how an operation is invoked. These apply to all
	// operations invoked for this client. Use functional options on operation call to
	// modify this list for per operation behavior.
	APIOptions []func(*middleware.Stack) error

	// MinDelay is the minimum amount of time to delay between retries. If unset,
	// ObjectNotExistsWaiter will use default minimum delay of 5 seconds. Note that
	// MinDelay must resolve to a value lesser than or equal to the MaxDelay.
	MinDelay time.Duration

	// MaxDelay is the maximum amount of time to delay between retries. If unset or set
	// to zero, ObjectNotExistsWaiter will use default max delay of 120 seconds. Note
	// that MaxDelay must resolve to value greater than or equal to the MinDelay.
	MaxDelay time.Duration

	// LogWaitAttempts is used to enable logging for waiter retry attempts
	LogWaitAttempts bool

	// Retryable is function that can be used to override the service defined
	// waiter-behavior based on operation output, or returned error. This function is
	// used by the waiter to decide if a state is retryable or a terminal state. By
	// default service-modeled logic will populate this option. This option can thus be
	// used to define a custom waiter state with fall-back to service-modeled waiter
	// state mutators.The function returns an error in case of a failure state. In case
	// of retry state, this function returns a bool value of true and nil error, while
	// in case of success it returns a bool value of false and nil error.
	Retryable func(context.Context, *HeadObjectInput, *HeadObjectOutput, error) (bool, error)
}

// ObjectNotExistsWaiter defines the waiters for ObjectNotExists
type ObjectNotExistsWaiter struct {
	client HeadObjectAPIClient

	options ObjectNotExistsWaiterOptions
}

// NewObjectNotExistsWaiter constructs a ObjectNotExistsWaiter.
func NewObjectNotExistsWaiter(client HeadObjectAPIClient, optFns ...func(*ObjectNotExistsWaiterOptions)) *ObjectNotExistsWaiter {
	options := ObjectNotExistsWaiterOptions{}
	options.MinDelay = 5 * time.Second
	options.MaxDelay = 120 * time.Second
	options.Retryable = objectNotExistsStateRetryable

	for _, fn := range optFns {
		fn(&options)
	}
	return &ObjectNotExistsWaiter{
		client:  client,
		options: options,
	}
}

// Wait calls the waiter function for ObjectNotExists waiter. The maxWaitDur is the
// maximum wait duration the waiter will wait. The maxWaitDur is required and must
// be greater than zero.
func (w *ObjectNotExistsWaiter) Wait(ctx context.Context, params *HeadObjectInput, maxWaitDur time.Duration, optFns ...func(*ObjectNotExistsWaiterOptions)) error {
	_, err := w.WaitForOutput(ctx, params, maxWaitDur, optFns...)
	return err
}

// WaitForOutput calls the waiter function for ObjectNotExists waiter and returns
// the output of the successful operation. The maxWaitDur is the maximum wait
// duration the waiter will wait. The maxWaitDur is required and must be greater
// than zero.
func (w *ObjectNotExistsWaiter) WaitForOutput(ctx context.Context, params *HeadObjectInput, maxWaitDur time.Duration, optFns ...func(*ObjectNotExistsWaiterOptions)) (*HeadObjectOutput, error) {
	if maxWaitDur <= 0 {
		return nil, fmt.Errorf("maximum wait time for waiter must be greater than zero")
	}

	options := w.options
	for _, fn := range optFns {
		fn(&options)
	}

	if options.MaxDelay <= 0 {
		options.MaxDelay = 120 * time.Second
	}

	if options.MinDelay > options.MaxDelay {
		return nil, fmt.Errorf("minimum waiter delay %v must be lesser than or equal to maximum waiter delay of %v.", options.MinDelay, options.MaxDelay)
	}

	ctx, cancelFn := context.WithTimeout(ctx, maxWaitDur)
	defer cancelFn()

	logger := smithywaiter.Logger{}
	remainingTime := maxWaitDur

	var attempt int64
	for {

		attempt++
		apiOptions := options.APIOptions
		start := time.Now()

		if options.LogWaitAttempts {
			logger.Attempt = attempt
			apiOptions = append([]func(*middleware.Stack) error{}, options.APIOptions...)
			apiOptions = append(apiOptions, logger.AddLogger)
		}

		out, err := w.client.HeadObject(ctx, params, func(o *Options) {
			o.APIOptions = append(o.APIOptions, apiOptions...)
		})

		retryable, err := options.Retryable(ctx, params, out, err)
		if err != nil {
			return nil, err
		}
		if !retryable {
			return out, nil
		}

		remainingTime -= time.Since(start)
		if remainingTime < options.MinDelay || remainingTime <= 0 {
			break
		}

		// compute exponential backoff between waiter retries
		delay, err := smithywaiter.ComputeDelay(
			attempt, options.MinDelay, options.MaxDelay, remainingTime,
		)
		if err != nil {
			return nil, fmt.Errorf("error computing waiter delay, %w", err)
		}

		remainingTime -= delay
		// sleep for the delay amount before invoking a request
		if err := smithytime.SleepWithContext(ctx, delay); err != nil {
			return nil, fmt.Errorf("request cancelled while waiting, %w", err)
		}
	}
	return nil, fmt.Errorf("exceeded max wait time for ObjectNotExists waiter")
}

func objectNotExistsStateRetryable(ctx context.Context, input *HeadObjectInput, output *HeadObjectOutput, err error) (bool, error) {

	if err != nil {
		var apiErr smithy.APIError
		ok := errors.As(err, &apiErr)
		if !ok {
			return false, fmt.Errorf("expected err to be of type smithy.APIError, got %w", err)
		}

		if "NotFound" == apiErr.ErrorCode() {
			return false, nil
		}
	}

	return true, nil
}

func newServiceMetadataMiddleware_opHeadObject(region string) *awsmiddleware.RegisterServiceMetadata {
	return &awsmiddleware.RegisterServiceMetadata{
		Region:        region,
		ServiceID:     ServiceID,
		SigningName:   "s3",
		OperationName: "HeadObject",
	}
}

// getHeadObjectBucketMember returns a pointer to string denoting a provided bucket
// member valueand a boolean indicating if the input has a modeled bucket name,
func getHeadObjectBucketMember(input interface{}) (*string, bool) {
	in := input.(*HeadObjectInput)
	if in.Bucket == nil {
		return nil, false
	}
	return in.Bucket, true
}
func addHeadObjectUpdateEndpoint(stack *middleware.Stack, options Options) error {
	return s3cust.UpdateEndpoint(stack, s3cust.UpdateEndpointOptions{
		Accessor: s3cust.UpdateEndpointParameterAccessor{
			GetBucketFromInput: getHeadObjectBucketMember,
		},
		UsePathStyle:                   options.UsePathStyle,
		UseAccelerate:                  options.UseAccelerate,
		SupportsAccelerate:             true,
		TargetS3ObjectLambda:           false,
		EndpointResolver:               options.EndpointResolver,
		EndpointResolverOptions:        options.EndpointOptions,
		UseARNRegion:                   options.UseARNRegion,
		DisableMultiRegionAccessPoints: options.DisableMultiRegionAccessPoints,
	})
}

// PresignHeadObject is used to generate a presigned HTTP Request which contains
// presigned URL, signed headers and HTTP method used.
func (c *PresignClient) PresignHeadObject(ctx context.Context, params *HeadObjectInput, optFns ...func(*PresignOptions)) (*v4.PresignedHTTPRequest, error) {
	if params == nil {
		params = &HeadObjectInput{}
	}
	options := c.options.copy()
	for _, fn := range optFns {
		fn(&options)
	}
	clientOptFns := append(options.ClientOptions, withNopHTTPClientAPIOption)

	result, _, err := c.client.invokeOperation(ctx, "HeadObject", params, clientOptFns,
		c.client.addOperationHeadObjectMiddlewares,
		presignConverter(options).convertToPresignMiddleware,
		addHeadObjectPayloadAsUnsigned,
	)
	if err != nil {
		return nil, err
	}

	out := result.(*v4.PresignedHTTPRequest)
	return out, nil
}

func addHeadObjectPayloadAsUnsigned(stack *middleware.Stack, options Options) error {
	v4.RemoveContentSHA256HeaderMiddleware(stack)
	v4.RemoveComputePayloadSHA256Middleware(stack)
	return v4.AddUnsignedPayloadMiddleware(stack)
}

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