201 lines
		
	
	
		
			6.7 KiB
		
	
	
	
		
			Go
		
	
	
	
			
		
		
	
	
			201 lines
		
	
	
		
			6.7 KiB
		
	
	
	
		
			Go
		
	
	
	
| // Copyright 2018, Google Inc.
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| // All rights reserved.
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| //
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| // Redistribution and use in source and binary forms, with or without
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| // modification, are permitted provided that the following conditions are
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| // met:
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| //
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| //     * Redistributions of source code must retain the above copyright
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| // notice, this list of conditions and the following disclaimer.
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| //     * Redistributions in binary form must reproduce the above
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| // copyright notice, this list of conditions and the following disclaimer
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| // in the documentation and/or other materials provided with the
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| // distribution.
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| //     * Neither the name of Google Inc. nor the names of its
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| // contributors may be used to endorse or promote products derived from
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| // this software without specific prior written permission.
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| //
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| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 
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| package gax
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| 
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| import (
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| 	"bytes"
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| 	"context"
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| 	"fmt"
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| 	"net/http"
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| 	"runtime"
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| 	"strings"
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| 	"unicode"
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| 
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| 	"github.com/googleapis/gax-go/v2/callctx"
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| 	"google.golang.org/grpc/metadata"
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| )
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| 
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| var (
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| 	// GoVersion is a header-safe representation of the current runtime
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| 	// environment's Go version. This is for GAX consumers that need to
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| 	// report the Go runtime version in API calls.
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| 	GoVersion string
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| 	// version is a package internal global variable for testing purposes.
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| 	version = runtime.Version
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| )
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| 
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| // versionUnknown is only used when the runtime version cannot be determined.
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| const versionUnknown = "UNKNOWN"
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| 
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| func init() {
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| 	GoVersion = goVersion()
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| }
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| 
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| // goVersion returns a Go runtime version derived from the runtime environment
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| // that is modified to be suitable for reporting in a header, meaning it has no
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| // whitespace. If it is unable to determine the Go runtime version, it returns
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| // versionUnknown.
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| func goVersion() string {
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| 	const develPrefix = "devel +"
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| 
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| 	s := version()
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| 	if strings.HasPrefix(s, develPrefix) {
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| 		s = s[len(develPrefix):]
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| 		if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
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| 			s = s[:p]
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| 		}
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| 		return s
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| 	} else if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
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| 		s = s[:p]
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| 	}
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| 
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| 	notSemverRune := func(r rune) bool {
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| 		return !strings.ContainsRune("0123456789.", r)
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| 	}
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| 
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| 	if strings.HasPrefix(s, "go1") {
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| 		s = s[2:]
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| 		var prerelease string
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| 		if p := strings.IndexFunc(s, notSemverRune); p >= 0 {
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| 			s, prerelease = s[:p], s[p:]
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| 		}
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| 		if strings.HasSuffix(s, ".") {
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| 			s += "0"
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| 		} else if strings.Count(s, ".") < 2 {
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| 			s += ".0"
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| 		}
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| 		if prerelease != "" {
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| 			// Some release candidates already have a dash in them.
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| 			if !strings.HasPrefix(prerelease, "-") {
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| 				prerelease = "-" + prerelease
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| 			}
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| 			s += prerelease
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| 		}
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| 		return s
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| 	}
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| 	return "UNKNOWN"
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| }
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| 
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| // XGoogHeader is for use by the Google Cloud Libraries only. See package
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| // [github.com/googleapis/gax-go/v2/callctx] for help setting/retrieving
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| // request/response headers.
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| //
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| // XGoogHeader formats key-value pairs.
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| // The resulting string is suitable for x-goog-api-client header.
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| func XGoogHeader(keyval ...string) string {
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| 	if len(keyval) == 0 {
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| 		return ""
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| 	}
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| 	if len(keyval)%2 != 0 {
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| 		panic("gax.Header: odd argument count")
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| 	}
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| 	var buf bytes.Buffer
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| 	for i := 0; i < len(keyval); i += 2 {
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| 		buf.WriteByte(' ')
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| 		buf.WriteString(keyval[i])
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| 		buf.WriteByte('/')
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| 		buf.WriteString(keyval[i+1])
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| 	}
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| 	return buf.String()[1:]
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| }
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| 
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| // InsertMetadataIntoOutgoingContext is for use by the Google Cloud Libraries
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| // only. See package [github.com/googleapis/gax-go/v2/callctx] for help
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| // setting/retrieving request/response headers.
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| //
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| // InsertMetadataIntoOutgoingContext returns a new context that merges the
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| // provided keyvals metadata pairs with any existing metadata/headers in the
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| // provided context. keyvals should have a corresponding value for every key
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| // provided. If there is an odd number of keyvals this method will panic.
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| // Existing values for keys will not be overwritten, instead provided values
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| // will be appended to the list of existing values.
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| func InsertMetadataIntoOutgoingContext(ctx context.Context, keyvals ...string) context.Context {
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| 	return metadata.NewOutgoingContext(ctx, insertMetadata(ctx, keyvals...))
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| }
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| 
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| // BuildHeaders is for use by the Google Cloud Libraries only. See package
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| // [github.com/googleapis/gax-go/v2/callctx] for help setting/retrieving
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| // request/response headers.
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| //
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| // BuildHeaders returns a new http.Header that merges the provided
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| // keyvals header pairs with any existing metadata/headers in the provided
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| // context. keyvals should have a corresponding value for every key provided.
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| // If there is an odd number of keyvals this method will panic.
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| // Existing values for keys will not be overwritten, instead provided values
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| // will be appended to the list of existing values.
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| func BuildHeaders(ctx context.Context, keyvals ...string) http.Header {
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| 	return http.Header(insertMetadata(ctx, keyvals...))
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| }
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| 
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| func insertMetadata(ctx context.Context, keyvals ...string) metadata.MD {
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| 	if len(keyvals)%2 != 0 {
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| 		panic(fmt.Sprintf("gax: an even number of key value pairs must be provided, got %d", len(keyvals)))
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| 	}
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| 	out, ok := metadata.FromOutgoingContext(ctx)
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| 	if !ok {
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| 		out = metadata.MD(make(map[string][]string))
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| 	}
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| 	headers := callctx.HeadersFromContext(ctx)
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| 
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| 	// x-goog-api-client is a special case that we want to make sure gets merged
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| 	// into a single header.
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| 	const xGoogHeader = "x-goog-api-client"
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| 	var mergedXgoogHeader strings.Builder
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| 
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| 	for k, vals := range headers {
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| 		if k == xGoogHeader {
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| 			// Merge all values for the x-goog-api-client header set on the ctx.
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| 			for _, v := range vals {
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| 				mergedXgoogHeader.WriteString(v)
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| 				mergedXgoogHeader.WriteRune(' ')
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| 			}
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| 			continue
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| 		}
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| 		out[k] = append(out[k], vals...)
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| 	}
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| 	for i := 0; i < len(keyvals); i = i + 2 {
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| 		out[keyvals[i]] = append(out[keyvals[i]], keyvals[i+1])
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| 
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| 		if keyvals[i] == xGoogHeader {
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| 			// Merge the x-goog-api-client header values set on the ctx with any
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| 			// values passed in for it from the client.
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| 			mergedXgoogHeader.WriteString(keyvals[i+1])
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| 			mergedXgoogHeader.WriteRune(' ')
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| 		}
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| 	}
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| 
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| 	// Add the x goog header back in, replacing the separate values that were set.
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| 	if mergedXgoogHeader.Len() > 0 {
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| 		out[xGoogHeader] = []string{mergedXgoogHeader.String()[:mergedXgoogHeader.Len()-1]}
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| 	}
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| 
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| 	return out
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| }
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