YQ Connector: prepare code base for S3 integration

1. Кодовая база Коннектора переписана с помощью Go дженериков так, чтобы добавление нового источника данных (в частности S3 + csv) максимально переиспользовало имеющийся код (чтобы сохранялась логика нарезания на блоки данных, учёт трафика и пр.)
2. API Connector расширено для работы с S3, но ещё пока не протестировано.

1 files changed, 167 insertions, 0 deletions

diff --git a/vendor/github.com/aws/smithy-go/transport/http/middleware_headers.go b/vendor/github.com/aws/smithy-go/transport/http/middleware_headers.go
new file mode 100644
index 0000000000..eac32b4bab
--- /dev/null
+++ b/vendor/github.com/aws/smithy-go/transport/http/middleware_headers.go
@@ -0,0 +1,167 @@
+package http
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/aws/smithy-go/middleware"
+)
+
+type isContentTypeAutoSet struct{}
+
+// SetIsContentTypeDefaultValue returns a Context specifying if the request's
+// content-type header was set to a default value.
+func SetIsContentTypeDefaultValue(ctx context.Context, isDefault bool) context.Context {
+	return context.WithValue(ctx, isContentTypeAutoSet{}, isDefault)
+}
+
+// GetIsContentTypeDefaultValue returns if the content-type HTTP header on the
+// request is a default value that was auto assigned by an operation
+// serializer. Allows middleware post serialization to know if the content-type
+// was auto set to a default value or not.
+//
+// Also returns false if the Context value was never updated to include if
+// content-type was set to a default value.
+func GetIsContentTypeDefaultValue(ctx context.Context) bool {
+	v, _ := ctx.Value(isContentTypeAutoSet{}).(bool)
+	return v
+}
+
+// AddNoPayloadDefaultContentTypeRemover Adds the DefaultContentTypeRemover
+// middleware to the stack after the operation serializer. This middleware will
+// remove the content-type header from the request if it was set as a default
+// value, and no request payload is present.
+//
+// Returns error if unable to add the middleware.
+func AddNoPayloadDefaultContentTypeRemover(stack *middleware.Stack) (err error) {
+	err = stack.Serialize.Insert(removeDefaultContentType{},
+		"OperationSerializer", middleware.After)
+	if err != nil {
+		return fmt.Errorf("failed to add %s serialize middleware, %w",
+			removeDefaultContentType{}.ID(), err)
+	}
+
+	return nil
+}
+
+// RemoveNoPayloadDefaultContentTypeRemover removes the
+// DefaultContentTypeRemover middleware from the stack. Returns an error if
+// unable to remove the middleware.
+func RemoveNoPayloadDefaultContentTypeRemover(stack *middleware.Stack) (err error) {
+	_, err = stack.Serialize.Remove(removeDefaultContentType{}.ID())
+	if err != nil {
+		return fmt.Errorf("failed to remove %s serialize middleware, %w",
+			removeDefaultContentType{}.ID(), err)
+
+	}
+	return nil
+}
+
+// removeDefaultContentType provides after serialization middleware that will
+// remove the content-type header from an HTTP request if the header was set as
+// a default value by the operation serializer, and there is no request payload.
+type removeDefaultContentType struct{}
+
+// ID returns the middleware ID
+func (removeDefaultContentType) ID() string { return "RemoveDefaultContentType" }
+
+// HandleSerialize implements the serialization middleware.
+func (removeDefaultContentType) HandleSerialize(
+	ctx context.Context, input middleware.SerializeInput, next middleware.SerializeHandler,
+) (
+	out middleware.SerializeOutput, meta middleware.Metadata, err error,
+) {
+	req, ok := input.Request.(*Request)
+	if !ok {
+		return out, meta, fmt.Errorf(
+			"unexpected request type %T for removeDefaultContentType middleware",
+			input.Request)
+	}
+
+	if GetIsContentTypeDefaultValue(ctx) && req.GetStream() == nil {
+		req.Header.Del("Content-Type")
+		input.Request = req
+	}
+
+	return next.HandleSerialize(ctx, input)
+}
+
+type headerValue struct {
+	header string
+	value  string
+	append bool
+}
+
+type headerValueHelper struct {
+	headerValues []headerValue
+}
+
+func (h *headerValueHelper) addHeaderValue(value headerValue) {
+	h.headerValues = append(h.headerValues, value)
+}
+
+func (h *headerValueHelper) ID() string {
+	return "HTTPHeaderHelper"
+}
+
+func (h *headerValueHelper) HandleBuild(ctx context.Context, in middleware.BuildInput, next middleware.BuildHandler) (out middleware.BuildOutput, metadata middleware.Metadata, err error) {
+	req, ok := in.Request.(*Request)
+	if !ok {
+		return out, metadata, fmt.Errorf("unknown transport type %T", in.Request)
+	}
+
+	for _, value := range h.headerValues {
+		if value.append {
+			req.Header.Add(value.header, value.value)
+		} else {
+			req.Header.Set(value.header, value.value)
+		}
+	}
+
+	return next.HandleBuild(ctx, in)
+}
+
+func getOrAddHeaderValueHelper(stack *middleware.Stack) (*headerValueHelper, error) {
+	id := (*headerValueHelper)(nil).ID()
+	m, ok := stack.Build.Get(id)
+	if !ok {
+		m = &headerValueHelper{}
+		err := stack.Build.Add(m, middleware.After)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	requestUserAgent, ok := m.(*headerValueHelper)
+	if !ok {
+		return nil, fmt.Errorf("%T for %s middleware did not match expected type", m, id)
+	}
+
+	return requestUserAgent, nil
+}
+
+// AddHeaderValue returns a stack mutator that adds the header value pair to header.
+// Appends to any existing values if present.
+func AddHeaderValue(header string, value string) func(stack *middleware.Stack) error {
+	return func(stack *middleware.Stack) error {
+		helper, err := getOrAddHeaderValueHelper(stack)
+		if err != nil {
+			return err
+		}
+		helper.addHeaderValue(headerValue{header: header, value: value, append: true})
+		return nil
+	}
+}
+
+// SetHeaderValue returns a stack mutator that adds the header value pair to header.
+// Replaces any existing values if present.
+func SetHeaderValue(header string, value string) func(stack *middleware.Stack) error {
+	return func(stack *middleware.Stack) error {
+		helper, err := getOrAddHeaderValueHelper(stack)
+		if err != nil {
+			return err
+		}
+		helper.addHeaderValue(headerValue{header: header, value: value, append: false})
+		return nil
+	}
+}