src

step_initialize.go (8683B)

---

 // Code generated by smithy-go/middleware/generate.go DO NOT EDIT.
 package middleware
 
 import (
 	"context"
 	"fmt"
 )
 
 // InitializeInput wraps the input parameters for the InitializeMiddlewares to
 // consume. InitializeMiddleware may modify the parameter value before
 // forwarding it along to the next InitializeHandler.
 
 type InitializeInput struct {
 	Parameters interface{}
 }
 
 // InitializeOutput provides the result returned by the next InitializeHandler.
 type InitializeOutput struct {
 	Result interface{}
 }
 
 // InitializeHandler provides the interface for the next handler the
 // InitializeMiddleware will call in the middleware chain.
 type InitializeHandler interface {
 	HandleInitialize(ctx context.Context, in InitializeInput) (
 		out InitializeOutput, metadata Metadata, err error,
 	)
 }
 
 // InitializeMiddleware provides the interface for middleware specific to the
 // initialize step. Delegates to the next InitializeHandler for further
 // processing.
 type InitializeMiddleware interface {
 	// ID returns a unique ID for the middleware in the InitializeStep. The step does not
 	// allow duplicate IDs.
 	ID() string
 
 	// HandleInitialize invokes the middleware behavior which must delegate to the next handler
 	// for the middleware chain to continue. The method must return a result or
 	// error to its caller.
 	HandleInitialize(ctx context.Context, in InitializeInput, next InitializeHandler) (
 		out InitializeOutput, metadata Metadata, err error,
 	)
 }
 
 // InitializeMiddlewareFunc returns a InitializeMiddleware with the unique ID provided,
 // and the func to be invoked.
 func InitializeMiddlewareFunc(id string, fn func(context.Context, InitializeInput, InitializeHandler) (InitializeOutput, Metadata, error)) InitializeMiddleware {
 	return initializeMiddlewareFunc{
 		id: id,
 		fn: fn,
 	}
 }
 
 type initializeMiddlewareFunc struct {
 	// Unique ID for the middleware.
 	id string
 
 	// Middleware function to be called.
 	fn func(context.Context, InitializeInput, InitializeHandler) (
 		InitializeOutput, Metadata, error,
 	)
 }
 
 // ID returns the unique ID for the middleware.
 func (s initializeMiddlewareFunc) ID() string { return s.id }
 
 // HandleInitialize invokes the middleware Fn.
 func (s initializeMiddlewareFunc) HandleInitialize(ctx context.Context, in InitializeInput, next InitializeHandler) (
 	out InitializeOutput, metadata Metadata, err error,
 ) {
 	return s.fn(ctx, in, next)
 }
 
 var _ InitializeMiddleware = (initializeMiddlewareFunc{})
 
 // InitializeStep provides the ordered grouping of InitializeMiddleware to be
 // invoked on a handler.
 type InitializeStep struct {
 	head *decoratedInitializeHandler
 	tail *decoratedInitializeHandler
 }
 
 // NewInitializeStep returns an InitializeStep ready to have middleware for
 // initialize added to it.
 func NewInitializeStep() *InitializeStep {
 	return &InitializeStep{}
 }
 
 var _ Middleware = (*InitializeStep)(nil)
 
 // ID returns the unique ID of the step as a middleware.
 func (s *InitializeStep) ID() string {
 	return "Initialize stack step"
 }
 
 // HandleMiddleware invokes the middleware by decorating the next handler
 // provided. Returns the result of the middleware and handler being invoked.
 //
 // Implements Middleware interface.
 func (s *InitializeStep) HandleMiddleware(ctx context.Context, in interface{}, next Handler) (
 	out interface{}, metadata Metadata, err error,
 ) {
 	sIn := InitializeInput{
 		Parameters: in,
 	}
 
 	wh := &initializeWrapHandler{next}
 	if s.head == nil {
 		res, metadata, err := wh.HandleInitialize(ctx, sIn)
 		return res.Result, metadata, err
 	}
 
 	s.tail.Next = wh
 	res, metadata, err := s.head.HandleInitialize(ctx, sIn)
 	return res.Result, metadata, err
 }
 
 // Get retrieves the middleware identified by id. If the middleware is not present, returns false.
 func (s *InitializeStep) Get(id string) (InitializeMiddleware, bool) {
 	found, _ := s.get(id)
 	if found == nil {
 		return nil, false
 	}
 
 	return found.With, true
 }
 
 // Add injects the middleware to the relative position of the middleware group.
 //
 // Add never returns an error. It used to for duplicate phases but this
 // behavior has since been removed as part of a performance optimization. The
 // return value from Add can be ignored.
 func (s *InitializeStep) Add(m InitializeMiddleware, pos RelativePosition) error {
 	if s.head == nil {
 		s.head = &decoratedInitializeHandler{nil, m}
 		s.tail = s.head
 		return nil
 	}
 
 	if pos == Before {
 		s.head = &decoratedInitializeHandler{s.head, m}
 	} else {
 		tail := &decoratedInitializeHandler{nil, m}
 		s.tail.Next = tail
 		s.tail = tail
 	}
 
 	return nil
 }
 
 // Insert injects the middleware relative to an existing middleware ID.
 // Returns error if the original middleware does not exist, or the middleware
 // being added already exists.
 func (s *InitializeStep) Insert(m InitializeMiddleware, relativeTo string, pos RelativePosition) error {
 	found, prev := s.get(relativeTo)
 	if found == nil {
 		return fmt.Errorf("not found: %s", m.ID())
 	}
 
 	if pos == Before {
 		if prev == nil { // at the front
 			s.head = &decoratedInitializeHandler{s.head, m}
 		} else { // somewhere in the middle
 			prev.Next = &decoratedInitializeHandler{found, m}
 		}
 	} else {
 		if found.Next == nil { // at the end
 			tail := &decoratedInitializeHandler{nil, m}
 			s.tail.Next = tail
 			s.tail = tail
 		} else { // somewhere in the middle
 			found.Next = &decoratedInitializeHandler{found.Next, m}
 		}
 	}
 
 	return nil
 }
 
 // Swap removes the middleware by id, replacing it with the new middleware.
 // Returns the middleware removed, or error if the middleware to be removed
 // doesn't exist.
 func (s *InitializeStep) Swap(id string, m InitializeMiddleware) (InitializeMiddleware, error) {
 	found, _ := s.get(id)
 	if found == nil {
 		return nil, fmt.Errorf("not found: %s", m.ID())
 	}
 
 	swapped := found.With
 	found.With = m
 	return swapped, nil
 }
 
 // Remove removes the middleware by id. Returns error if the middleware
 // doesn't exist.
 func (s *InitializeStep) Remove(id string) (InitializeMiddleware, error) {
 	found, prev := s.get(id)
 	if found == nil {
 		return nil, fmt.Errorf("not found: %s", id)
 	}
 
 	if s.head == s.tail { // it's the only one
 		s.head = nil
 		s.tail = nil
 	} else if found == s.head { // at the front
 		s.head = s.head.Next.(*decoratedInitializeHandler)
 	} else if found == s.tail { // at the end
 		prev.Next = nil
 		s.tail = prev
 	} else {
 		prev.Next = found.Next // somewhere in the middle
 	}
 
 	return found.With, nil
 }
 
 // List returns a list of the middleware in the step.
 func (s *InitializeStep) List() []string {
 	var ids []string
 	for h := s.head; h != nil; {
 		ids = append(ids, h.With.ID())
 		if h.Next == nil {
 			break
 		}
 
 		// once executed, tail.Next of the list will be set to an
 		// *initializeWrapHandler, make sure to check for that
 		if hnext, ok := h.Next.(*decoratedInitializeHandler); ok {
 			h = hnext
 		} else {
 			break
 		}
 	}
 	return ids
 }
 
 // Clear removes all middleware in the step.
 func (s *InitializeStep) Clear() {
 	s.head = nil
 	s.tail = nil
 }
 
 func (s *InitializeStep) get(id string) (found, prev *decoratedInitializeHandler) {
 	for h := s.head; h != nil; {
 		if h.With.ID() == id {
 			found = h
 			return
 		}
 		prev = h
 		if h.Next == nil {
 			return
 		}
 
 		// once executed, tail.Next of the list will be set to an
 		// *initializeWrapHandler
 		h, _ = h.Next.(*decoratedInitializeHandler)
 	}
 	return
 }
 
 type initializeWrapHandler struct {
 	Next Handler
 }
 
 var _ InitializeHandler = (*initializeWrapHandler)(nil)
 
 // HandleInitialize implements InitializeHandler, converts types and delegates to underlying
 // generic handler.
 func (w initializeWrapHandler) HandleInitialize(ctx context.Context, in InitializeInput) (
 	out InitializeOutput, metadata Metadata, err error,
 ) {
 	res, metadata, err := w.Next.Handle(ctx, in.Parameters)
 	return InitializeOutput{
 		Result: res,
 	}, metadata, err
 }
 
 type decoratedInitializeHandler struct {
 	Next InitializeHandler
 	With InitializeMiddleware
 }
 
 var _ InitializeHandler = (*decoratedInitializeHandler)(nil)
 
 func (h decoratedInitializeHandler) HandleInitialize(ctx context.Context, in InitializeInput) (
 	out InitializeOutput, metadata Metadata, err error,
 ) {
 	return h.With.HandleInitialize(ctx, in, h.Next)
 }
 
 // InitializeHandlerFunc provides a wrapper around a function to be used as initializeMiddleware.
 type InitializeHandlerFunc func(context.Context, InitializeInput) (InitializeOutput, Metadata, error)
 
 // HandleInitialize calls the wrapped function with the provided arguments.
 func (f InitializeHandlerFunc) HandleInitialize(ctx context.Context, in InitializeInput) (InitializeOutput, Metadata, error) {
 	return f(ctx, in)
 }
 
 var _ InitializeHandler = InitializeHandlerFunc(nil)