vendor/github.com/googleapis/gax-go/v2/header.go - cos/cos-extensions - Git at Google

 // Copyright 2018, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 // copyright notice, this list of conditions and the following disclaimer
 // in the documentation and/or other materials provided with the
 // distribution.
 //     * Neither the name of Google Inc. nor the names of its
 // contributors may be used to endorse or promote products derived from
 // this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 package gax

 import (
 	"bytes"
 	"context"
 	"fmt"
 	"net/http"
 	"runtime"
 	"strings"
 	"unicode"

 	"github.com/googleapis/gax-go/v2/callctx"
 	"google.golang.org/grpc/metadata"
 )

 var (
 	// GoVersion is a header-safe representation of the current runtime
 	// environment's Go version. This is for GAX consumers that need to
 	// report the Go runtime version in API calls.
 	GoVersion string
 	// version is a package internal global variable for testing purposes.
 	version = runtime.Version
 )

 // versionUnknown is only used when the runtime version cannot be determined.
 const versionUnknown = "UNKNOWN"

 func init() {
 	GoVersion = goVersion()
 }

 // goVersion returns a Go runtime version derived from the runtime environment
 // that is modified to be suitable for reporting in a header, meaning it has no
 // whitespace. If it is unable to determine the Go runtime version, it returns
 // versionUnknown.
 func goVersion() string {
 	const develPrefix = "devel +"

 	s := version()
 	if strings.HasPrefix(s, develPrefix) {
 		s = s[len(develPrefix):]
 		if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
 			s = s[:p]
 		}
 		return s
 	} else if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
 		s = s[:p]
 	}

 	notSemverRune := func(r rune) bool {
 		return !strings.ContainsRune("0123456789.", r)
 	}

 	if strings.HasPrefix(s, "go1") {
 		s = s[2:]
 		var prerelease string
 		if p := strings.IndexFunc(s, notSemverRune); p >= 0 {
 			s, prerelease = s[:p], s[p:]
 		}
 		if strings.HasSuffix(s, ".") {
 			s += "0"
 		} else if strings.Count(s, ".") < 2 {
 			s += ".0"
 		}
 		if prerelease != "" {
 			// Some release candidates already have a dash in them.
 			if !strings.HasPrefix(prerelease, "-") {
 				prerelease = "-" + prerelease
 			}
 			s += prerelease
 		}
 		return s
 	}
 	return "UNKNOWN"
 }

 // XGoogHeader is for use by the Google Cloud Libraries only. See package
 // [github.com/googleapis/gax-go/v2/callctx] for help setting/retrieving
 // request/response headers.
 //
 // XGoogHeader formats key-value pairs.
 // The resulting string is suitable for x-goog-api-client header.
 func XGoogHeader(keyval ...string) string {
 	if len(keyval) == 0 {
 		return ""
 	}
 	if len(keyval)%2 != 0 {
 		panic("gax.Header: odd argument count")
 	}
 	var buf bytes.Buffer
 	for i := 0; i < len(keyval); i += 2 {
 		buf.WriteByte(' ')
 		buf.WriteString(keyval[i])
 		buf.WriteByte('/')
 		buf.WriteString(keyval[i+1])
 	}
 	return buf.String()[1:]
 }

 // InsertMetadataIntoOutgoingContext is for use by the Google Cloud Libraries
 // only. See package [github.com/googleapis/gax-go/v2/callctx] for help
 // setting/retrieving request/response headers.
 //
 // InsertMetadataIntoOutgoingContext returns a new context that merges the
 // provided keyvals metadata pairs with any existing metadata/headers in the
 // provided context. keyvals should have a corresponding value for every key
 // provided. If there is an odd number of keyvals this method will panic.
 // Existing values for keys will not be overwritten, instead provided values
 // will be appended to the list of existing values.
 func InsertMetadataIntoOutgoingContext(ctx context.Context, keyvals ...string) context.Context {
 	return metadata.NewOutgoingContext(ctx, insertMetadata(ctx, keyvals...))
 }

 // BuildHeaders is for use by the Google Cloud Libraries only. See package
 // [github.com/googleapis/gax-go/v2/callctx] for help setting/retrieving
 // request/response headers.
 //
 // BuildHeaders returns a new http.Header that merges the provided
 // keyvals header pairs with any existing metadata/headers in the provided
 // context. keyvals should have a corresponding value for every key provided.
 // If there is an odd number of keyvals this method will panic.
 // Existing values for keys will not be overwritten, instead provided values
 // will be appended to the list of existing values.
 func BuildHeaders(ctx context.Context, keyvals ...string) http.Header {
 	return http.Header(insertMetadata(ctx, keyvals...))
 }

 func insertMetadata(ctx context.Context, keyvals ...string) metadata.MD {
 	if len(keyvals)%2 != 0 {
 		panic(fmt.Sprintf("gax: an even number of key value pairs must be provided, got %d", len(keyvals)))
 	}
 	out, ok := metadata.FromOutgoingContext(ctx)
 	if !ok {
 		out = metadata.MD(make(map[string][]string))
 	}
 	headers := callctx.HeadersFromContext(ctx)

 	// x-goog-api-client is a special case that we want to make sure gets merged
 	// into a single header.
 	const xGoogHeader = "x-goog-api-client"
 	var mergedXgoogHeader strings.Builder

 	for k, vals := range headers {
 		if k == xGoogHeader {
 			// Merge all values for the x-goog-api-client header set on the ctx.
 			for _, v := range vals {
 				mergedXgoogHeader.WriteString(v)
 				mergedXgoogHeader.WriteRune(' ')
 			}
 			continue
 		}
 		out[k] = append(out[k], vals...)
 	}
 	for i := 0; i < len(keyvals); i = i + 2 {
 		out[keyvals[i]] = append(out[keyvals[i]], keyvals[i+1])

 		if keyvals[i] == xGoogHeader {
 			// Merge the x-goog-api-client header values set on the ctx with any
 			// values passed in for it from the client.
 			mergedXgoogHeader.WriteString(keyvals[i+1])
 			mergedXgoogHeader.WriteRune(' ')
 		}
 	}

 	// Add the x goog header back in, replacing the separate values that were set.
 	if mergedXgoogHeader.Len() > 0 {
 		out[xGoogHeader] = []string{mergedXgoogHeader.String()[:mergedXgoogHeader.Len()-1]}
 	}

 	return out
 }
	// Copyright 2018, Google Inc.
	// All rights reserved.
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are
	// met:
	//
	// * Redistributions of source code must retain the above copyright
	// notice, this list of conditions and the following disclaimer.
	// * Redistributions in binary form must reproduce the above
	// copyright notice, this list of conditions and the following disclaimer
	// in the documentation and/or other materials provided with the
	// distribution.
	// * Neither the name of Google Inc. nor the names of its
	// contributors may be used to endorse or promote products derived from
	// this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	package gax

	import (
	"bytes"
	"context"
	"fmt"
	"net/http"
	"runtime"
	"strings"
	"unicode"

	"github.com/googleapis/gax-go/v2/callctx"
	"google.golang.org/grpc/metadata"
	)

	var (
	// GoVersion is a header-safe representation of the current runtime
	// environment's Go version. This is for GAX consumers that need to
	// report the Go runtime version in API calls.
	GoVersion string
	// version is a package internal global variable for testing purposes.
	version = runtime.Version
	)

	// versionUnknown is only used when the runtime version cannot be determined.
	const versionUnknown = "UNKNOWN"

	func init() {
	GoVersion = goVersion()
	}

	// goVersion returns a Go runtime version derived from the runtime environment
	// that is modified to be suitable for reporting in a header, meaning it has no
	// whitespace. If it is unable to determine the Go runtime version, it returns
	// versionUnknown.
	func goVersion() string {
	const develPrefix = "devel +"

	s := version()
	if strings.HasPrefix(s, develPrefix) {
	s = s[len(develPrefix):]
	if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
	s = s[:p]
	}
	return s
	} else if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
	s = s[:p]
	}

	notSemverRune := func(r rune) bool {
	return !strings.ContainsRune("0123456789.", r)
	}

	if strings.HasPrefix(s, "go1") {
	s = s[2:]
	var prerelease string
	if p := strings.IndexFunc(s, notSemverRune); p >= 0 {
	s, prerelease = s[:p], s[p:]
	}
	if strings.HasSuffix(s, ".") {
	s += "0"
	} else if strings.Count(s, ".") < 2 {
	s += ".0"
	}
	if prerelease != "" {
	// Some release candidates already have a dash in them.
	if !strings.HasPrefix(prerelease, "-") {
	prerelease = "-" + prerelease
	}
	s += prerelease
	}
	return s
	}
	return "UNKNOWN"
	}

	// XGoogHeader is for use by the Google Cloud Libraries only. See package
	// [github.com/googleapis/gax-go/v2/callctx] for help setting/retrieving
	// request/response headers.
	//
	// XGoogHeader formats key-value pairs.
	// The resulting string is suitable for x-goog-api-client header.
	func XGoogHeader(keyval ...string) string {
	if len(keyval) == 0 {
	return ""
	}
	if len(keyval)%2 != 0 {
	panic("gax.Header: odd argument count")
	}
	var buf bytes.Buffer
	for i := 0; i < len(keyval); i += 2 {
	buf.WriteByte(' ')
	buf.WriteString(keyval[i])
	buf.WriteByte('/')
	buf.WriteString(keyval[i+1])
	}
	return buf.String()[1:]
	}

	// InsertMetadataIntoOutgoingContext is for use by the Google Cloud Libraries
	// only. See package [github.com/googleapis/gax-go/v2/callctx] for help
	// setting/retrieving request/response headers.
	//
	// InsertMetadataIntoOutgoingContext returns a new context that merges the
	// provided keyvals metadata pairs with any existing metadata/headers in the
	// provided context. keyvals should have a corresponding value for every key
	// provided. If there is an odd number of keyvals this method will panic.
	// Existing values for keys will not be overwritten, instead provided values
	// will be appended to the list of existing values.
	func InsertMetadataIntoOutgoingContext(ctx context.Context, keyvals ...string) context.Context {
	return metadata.NewOutgoingContext(ctx, insertMetadata(ctx, keyvals...))
	}

	// BuildHeaders is for use by the Google Cloud Libraries only. See package
	// [github.com/googleapis/gax-go/v2/callctx] for help setting/retrieving
	// request/response headers.
	//
	// BuildHeaders returns a new http.Header that merges the provided
	// keyvals header pairs with any existing metadata/headers in the provided
	// context. keyvals should have a corresponding value for every key provided.
	// If there is an odd number of keyvals this method will panic.
	// Existing values for keys will not be overwritten, instead provided values
	// will be appended to the list of existing values.
	func BuildHeaders(ctx context.Context, keyvals ...string) http.Header {
	return http.Header(insertMetadata(ctx, keyvals...))
	}

	func insertMetadata(ctx context.Context, keyvals ...string) metadata.MD {
	if len(keyvals)%2 != 0 {
	panic(fmt.Sprintf("gax: an even number of key value pairs must be provided, got %d", len(keyvals)))
	}
	out, ok := metadata.FromOutgoingContext(ctx)
	if !ok {
	out = metadata.MD(make(map[string][]string))
	}
	headers := callctx.HeadersFromContext(ctx)

	// x-goog-api-client is a special case that we want to make sure gets merged
	// into a single header.
	const xGoogHeader = "x-goog-api-client"
	var mergedXgoogHeader strings.Builder

	for k, vals := range headers {
	if k == xGoogHeader {
	// Merge all values for the x-goog-api-client header set on the ctx.
	for _, v := range vals {
	mergedXgoogHeader.WriteString(v)
	mergedXgoogHeader.WriteRune(' ')
	}
	continue
	}
	out[k] = append(out[k], vals...)
	}
	for i := 0; i < len(keyvals); i = i + 2 {
	out[keyvals[i]] = append(out[keyvals[i]], keyvals[i+1])

	if keyvals[i] == xGoogHeader {
	// Merge the x-goog-api-client header values set on the ctx with any
	// values passed in for it from the client.
	mergedXgoogHeader.WriteString(keyvals[i+1])
	mergedXgoogHeader.WriteRune(' ')
	}
	}

	// Add the x goog header back in, replacing the separate values that were set.
	if mergedXgoogHeader.Len() > 0 {
	out[xGoogHeader] = []string{mergedXgoogHeader.String()[:mergedXgoogHeader.Len()-1]}
	}

	return out
	}