src

step_build.go (8065B)

---

 // Code generated by smithy-go/middleware/generate.go DO NOT EDIT.
 package middleware
 
 import (
 	"context"
 	"fmt"
 )
 
 // BuildInput provides the input parameters for the BuildMiddleware to consume.
 // BuildMiddleware may modify the Request value before forwarding the input
 // along to the next BuildHandler.
 type BuildInput struct {
 	Request interface{}
 }
 
 // BuildOutput provides the result returned by the next BuildHandler.
 type BuildOutput struct {
 	Result interface{}
 }
 
 // BuildHandler provides the interface for the next handler the
 // BuildMiddleware will call in the middleware chain.
 type BuildHandler interface {
 	HandleBuild(ctx context.Context, in BuildInput) (
 		out BuildOutput, metadata Metadata, err error,
 	)
 }
 
 // BuildMiddleware provides the interface for middleware specific to the
 // build step. Delegates to the next BuildHandler for further
 // processing.
 type BuildMiddleware interface {
 	// ID returns a unique ID for the middleware in the BuildStep. The step does not
 	// allow duplicate IDs.
 	ID() string
 
 	// HandleBuild 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.
 	HandleBuild(ctx context.Context, in BuildInput, next BuildHandler) (
 		out BuildOutput, metadata Metadata, err error,
 	)
 }
 
 // BuildMiddlewareFunc returns a BuildMiddleware with the unique ID provided,
 // and the func to be invoked.
 func BuildMiddlewareFunc(id string, fn func(context.Context, BuildInput, BuildHandler) (BuildOutput, Metadata, error)) BuildMiddleware {
 	return buildMiddlewareFunc{
 		id: id,
 		fn: fn,
 	}
 }
 
 type buildMiddlewareFunc struct {
 	// Unique ID for the middleware.
 	id string
 
 	// Middleware function to be called.
 	fn func(context.Context, BuildInput, BuildHandler) (
 		BuildOutput, Metadata, error,
 	)
 }
 
 // ID returns the unique ID for the middleware.
 func (s buildMiddlewareFunc) ID() string { return s.id }
 
 // HandleBuild invokes the middleware Fn.
 func (s buildMiddlewareFunc) HandleBuild(ctx context.Context, in BuildInput, next BuildHandler) (
 	out BuildOutput, metadata Metadata, err error,
 ) {
 	return s.fn(ctx, in, next)
 }
 
 var _ BuildMiddleware = (buildMiddlewareFunc{})
 
 // BuildStep provides the ordered grouping of BuildMiddleware to be
 // invoked on a handler.
 type BuildStep struct {
 	head *decoratedBuildHandler
 	tail *decoratedBuildHandler
 }
 
 // NewBuildStep returns an BuildStep ready to have middleware for
 // build added to it.
 func NewBuildStep() *BuildStep {
 	return &BuildStep{}
 }
 
 var _ Middleware = (*BuildStep)(nil)
 
 // ID returns the unique ID of the step as a middleware.
 func (s *BuildStep) ID() string {
 	return "Build 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 *BuildStep) HandleMiddleware(ctx context.Context, in interface{}, next Handler) (
 	out interface{}, metadata Metadata, err error,
 ) {
 	sIn := BuildInput{
 		Request: in,
 	}
 
 	wh := &buildWrapHandler{next}
 	if s.head == nil {
 		res, metadata, err := wh.HandleBuild(ctx, sIn)
 		return res.Result, metadata, err
 	}
 
 	s.tail.Next = wh
 	res, metadata, err := s.head.HandleBuild(ctx, sIn)
 	return res.Result, metadata, err
 }
 
 // Get retrieves the middleware identified by id. If the middleware is not present, returns false.
 func (s *BuildStep) Get(id string) (BuildMiddleware, 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 *BuildStep) Add(m BuildMiddleware, pos RelativePosition) error {
 	if s.head == nil {
 		s.head = &decoratedBuildHandler{nil, m}
 		s.tail = s.head
 		return nil
 	}
 
 	if pos == Before {
 		s.head = &decoratedBuildHandler{s.head, m}
 	} else {
 		tail := &decoratedBuildHandler{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 *BuildStep) Insert(m BuildMiddleware, 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 = &decoratedBuildHandler{s.head, m}
 		} else { // somewhere in the middle
 			prev.Next = &decoratedBuildHandler{found, m}
 		}
 	} else {
 		if found.Next == nil { // at the end
 			tail := &decoratedBuildHandler{nil, m}
 			s.tail.Next = tail
 			s.tail = tail
 		} else { // somewhere in the middle
 			found.Next = &decoratedBuildHandler{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 *BuildStep) Swap(id string, m BuildMiddleware) (BuildMiddleware, 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 *BuildStep) Remove(id string) (BuildMiddleware, 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.(*decoratedBuildHandler)
 	} 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 *BuildStep) 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
 		// *buildWrapHandler, make sure to check for that
 		if hnext, ok := h.Next.(*decoratedBuildHandler); ok {
 			h = hnext
 		} else {
 			break
 		}
 	}
 	return ids
 }
 
 // Clear removes all middleware in the step.
 func (s *BuildStep) Clear() {
 	s.head = nil
 	s.tail = nil
 }
 
 func (s *BuildStep) get(id string) (found, prev *decoratedBuildHandler) {
 	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
 		// *buildWrapHandler
 		h, _ = h.Next.(*decoratedBuildHandler)
 	}
 	return
 }
 
 type buildWrapHandler struct {
 	Next Handler
 }
 
 var _ BuildHandler = (*buildWrapHandler)(nil)
 
 // HandleBuild implements BuildHandler, converts types and delegates to underlying
 // generic handler.
 func (w buildWrapHandler) HandleBuild(ctx context.Context, in BuildInput) (
 	out BuildOutput, metadata Metadata, err error,
 ) {
 	res, metadata, err := w.Next.Handle(ctx, in.Request)
 	return BuildOutput{
 		Result: res,
 	}, metadata, err
 }
 
 type decoratedBuildHandler struct {
 	Next BuildHandler
 	With BuildMiddleware
 }
 
 var _ BuildHandler = (*decoratedBuildHandler)(nil)
 
 func (h decoratedBuildHandler) HandleBuild(ctx context.Context, in BuildInput) (
 	out BuildOutput, metadata Metadata, err error,
 ) {
 	return h.With.HandleBuild(ctx, in, h.Next)
 }
 
 // BuildHandlerFunc provides a wrapper around a function to be used as buildMiddleware.
 type BuildHandlerFunc func(context.Context, BuildInput) (BuildOutput, Metadata, error)
 
 // HandleBuild calls the wrapped function with the provided arguments.
 func (f BuildHandlerFunc) HandleBuild(ctx context.Context, in BuildInput) (BuildOutput, Metadata, error) {
 	return f(ctx, in)
 }
 
 var _ BuildHandler = BuildHandlerFunc(nil)