podman

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// Copyright 2013 The Go Authors. All rights reserved.
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//
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file or at
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// https://developers.google.com/open-source/licenses/bsd.
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// this file was taken from the github.com/golang/gddo repository
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package middleware
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import (
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	"net/http"
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	"strings"
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	"github.com/go-openapi/runtime/middleware/header"
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)
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// NegotiateContentEncoding returns the best offered content encoding for the
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// request's Accept-Encoding header. If two offers match with equal weight and
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// then the offer earlier in the list is preferred. If no offers are
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// acceptable, then "" is returned.
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func NegotiateContentEncoding(r *http.Request, offers []string) string {
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	bestOffer := "identity"
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	bestQ := -1.0
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	specs := header.ParseAccept(r.Header, "Accept-Encoding")
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	for _, offer := range offers {
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		for _, spec := range specs {
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			if spec.Q > bestQ &&
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				(spec.Value == "*" || spec.Value == offer) {
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				bestQ = spec.Q
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				bestOffer = offer
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			}
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		}
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	}
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	if bestQ == 0 {
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		bestOffer = ""
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	}
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	return bestOffer
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}
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// NegotiateContentType returns the best offered content type for the request's
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// Accept header. If two offers match with equal weight, then the more specific
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// offer is preferred.  For example, text/* trumps */*. If two offers match
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// with equal weight and specificity, then the offer earlier in the list is
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// preferred. If no offers match, then defaultOffer is returned.
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func NegotiateContentType(r *http.Request, offers []string, defaultOffer string) string {
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	bestOffer := defaultOffer
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	bestQ := -1.0
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	bestWild := 3
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	specs := header.ParseAccept(r.Header, "Accept")
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	for _, rawOffer := range offers {
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		offer := normalizeOffer(rawOffer)
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		// No Accept header: just return the first offer.
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		if len(specs) == 0 {
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			return rawOffer
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		}
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		for _, spec := range specs {
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			switch {
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			case spec.Q == 0.0:
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				// ignore
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			case spec.Q < bestQ:
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				// better match found
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			case spec.Value == "*/*":
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				if spec.Q > bestQ || bestWild > 2 {
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					bestQ = spec.Q
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					bestWild = 2
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					bestOffer = rawOffer
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				}
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			case strings.HasSuffix(spec.Value, "/*"):
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				if strings.HasPrefix(offer, spec.Value[:len(spec.Value)-1]) &&
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					(spec.Q > bestQ || bestWild > 1) {
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					bestQ = spec.Q
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					bestWild = 1
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					bestOffer = rawOffer
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				}
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			default:
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				if spec.Value == offer &&
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					(spec.Q > bestQ || bestWild > 0) {
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					bestQ = spec.Q
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					bestWild = 0
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					bestOffer = rawOffer
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				}
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			}
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		}
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	}
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	return bestOffer
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}
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func normalizeOffers(orig []string) (norm []string) {
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	for _, o := range orig {
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		norm = append(norm, normalizeOffer(o))
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	}
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	return
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}
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func normalizeOffer(orig string) string {
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	return strings.SplitN(orig, ";", 2)[0]
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}
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