info.go

Documentation: cloud.google.com/go/auth/credentials/internal/externalaccount

     1  // Copyright 2023 Google LLC
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package externalaccount
    16  
    17  import (
    18  	"runtime"
    19  	"strings"
    20  	"unicode"
    21  )
    22  
    23  var (
    24  	// version is a package internal global variable for testing purposes.
    25  	version = runtime.Version
    26  )
    27  
    28  // versionUnknown is only used when the runtime version cannot be determined.
    29  const versionUnknown = "UNKNOWN"
    30  
    31  // goVersion returns a Go runtime version derived from the runtime environment
    32  // that is modified to be suitable for reporting in a header, meaning it has no
    33  // whitespace. If it is unable to determine the Go runtime version, it returns
    34  // versionUnknown.
    35  func goVersion() string {
    36  	const develPrefix = "devel +"
    37  
    38  	s := version()
    39  	if strings.HasPrefix(s, develPrefix) {
    40  		s = s[len(develPrefix):]
    41  		if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
    42  			s = s[:p]
    43  		}
    44  		return s
    45  	} else if p := strings.IndexFunc(s, unicode.IsSpace); p >= 0 {
    46  		s = s[:p]
    47  	}
    48  
    49  	notSemverRune := func(r rune) bool {
    50  		return !strings.ContainsRune("0123456789.", r)
    51  	}
    52  
    53  	if strings.HasPrefix(s, "go1") {
    54  		s = s[2:]
    55  		var prerelease string
    56  		if p := strings.IndexFunc(s, notSemverRune); p >= 0 {
    57  			s, prerelease = s[:p], s[p:]
    58  		}
    59  		if strings.HasSuffix(s, ".") {
    60  			s += "0"
    61  		} else if strings.Count(s, ".") < 2 {
    62  			s += ".0"
    63  		}
    64  		if prerelease != "" {
    65  			// Some release candidates already have a dash in them.
    66  			if !strings.HasPrefix(prerelease, "-") {
    67  				prerelease = "-" + prerelease
    68  			}
    69  			s += prerelease
    70  		}
    71  		return s
    72  	}
    73  	return versionUnknown
    74  }
    75
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