s3 cache client-side support

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

vendor/github.com/aws/smithy-go/middleware/step_initialize.go

@@ -0,0 +1,211 @@
+package middleware
+
+import "context"
+
+// 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 {
+	ids *orderedIDs
+}
+
+// NewInitializeStep returns an InitializeStep ready to have middleware for
+// initialization added to it.
+func NewInitializeStep() *InitializeStep {
+	return &InitializeStep{
+		ids: newOrderedIDs(),
+	}
+}
+
+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,
+) {
+	order := s.ids.GetOrder()
+
+	var h InitializeHandler = initializeWrapHandler{Next: next}
+	for i := len(order) - 1; i >= 0; i-- {
+		h = decoratedInitializeHandler{
+			Next: h,
+			With: order[i].(InitializeMiddleware),
+		}
+	}
+
+	sIn := InitializeInput{
+		Parameters: in,
+	}
+
+	res, metadata, err := h.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) {
+	get, ok := s.ids.Get(id)
+	if !ok {
+		return nil, false
+	}
+	return get.(InitializeMiddleware), ok
+}
+
+// Add injects the middleware to the relative position of the middleware group.
+// Returns an error if the middleware already exists.
+func (s *InitializeStep) Add(m InitializeMiddleware, pos RelativePosition) error {
+	return s.ids.Add(m, pos)
+}
+
+// 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 {
+	return s.ids.Insert(m, relativeTo, pos)
+}
+
+// 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) {
+	removed, err := s.ids.Swap(id, m)
+	if err != nil {
+		return nil, err
+	}
+
+	return removed.(InitializeMiddleware), nil
+}
+
+// Remove removes the middleware by id. Returns error if the middleware
+// doesn't exist.
+func (s *InitializeStep) Remove(id string) (InitializeMiddleware, error) {
+	removed, err := s.ids.Remove(id)
+	if err != nil {
+		return nil, err
+	}
+
+	return removed.(InitializeMiddleware), nil
+}
+
+// List returns a list of the middleware in the step.
+func (s *InitializeStep) List() []string {
+	return s.ids.List()
+}
+
+// Clear removes all middleware in the step.
+func (s *InitializeStep) Clear() {
+	s.ids.Clear()
+}
+
+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 an initialize middleware handler.
+type InitializeHandlerFunc func(context.Context, InitializeInput) (InitializeOutput, Metadata, error)
+
+// HandleInitialize calls the wrapped function with the provided arguments.
+func (i InitializeHandlerFunc) HandleInitialize(ctx context.Context, in InitializeInput) (InitializeOutput, Metadata, error) {
+	return i(ctx, in)
+}
+
+var _ InitializeHandler = InitializeHandlerFunc(nil)