github.com/xushiwei/go@v0.0.0-20130601165731-2b9d83f45bc9/src/cmd/go/env.go (about)

     1  // Copyright 2012 The Go Authors.  All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package main
     6  
     7  import (
     8  	"fmt"
     9  	"os"
    10  	"runtime"
    11  	"strings"
    12  )
    13  
    14  var cmdEnv = &Command{
    15  	Run:       runEnv,
    16  	UsageLine: "env [var ...]",
    17  	Short:     "print Go environment information",
    18  	Long: `
    19  Env prints Go environment information.
    20  
    21  By default env prints information as a shell script
    22  (on Windows, a batch file).  If one or more variable
    23  names is given as arguments,  env prints the value of
    24  each named variable on its own line.
    25  	`,
    26  }
    27  
    28  type envVar struct {
    29  	name, value string
    30  }
    31  
    32  func mkEnv() []envVar {
    33  	var b builder
    34  	b.init()
    35  
    36  	env := []envVar{
    37  		{"GOARCH", goarch},
    38  		{"GOBIN", gobin},
    39  		{"GOCHAR", archChar},
    40  		{"GOEXE", exeSuffix},
    41  		{"GOHOSTARCH", runtime.GOARCH},
    42  		{"GOHOSTOS", runtime.GOOS},
    43  		{"GOOS", goos},
    44  		{"GOPATH", os.Getenv("GOPATH")},
    45  		{"GORACE", os.Getenv("GORACE")},
    46  		{"GOROOT", goroot},
    47  		{"GOTOOLDIR", toolDir},
    48  	}
    49  
    50  	if goos != "plan9" {
    51  		cmd := b.gccCmd(".")
    52  		env = append(env, envVar{"CC", cmd[0]})
    53  		env = append(env, envVar{"GOGCCFLAGS", strings.Join(cmd[3:], " ")})
    54  	}
    55  
    56  	if buildContext.CgoEnabled {
    57  		env = append(env, envVar{"CGO_ENABLED", "1"})
    58  	} else {
    59  		env = append(env, envVar{"CGO_ENABLED", "0"})
    60  	}
    61  
    62  	return env
    63  }
    64  
    65  func findEnv(env []envVar, name string) string {
    66  	for _, e := range env {
    67  		if e.name == name {
    68  			return e.value
    69  		}
    70  	}
    71  	return ""
    72  }
    73  
    74  func runEnv(cmd *Command, args []string) {
    75  	env := mkEnv()
    76  	if len(args) > 0 {
    77  		for _, name := range args {
    78  			fmt.Printf("%s\n", findEnv(env, name))
    79  		}
    80  		return
    81  	}
    82  
    83  	switch runtime.GOOS {
    84  	default:
    85  		for _, e := range env {
    86  			fmt.Printf("%s=\"%s\"\n", e.name, e.value)
    87  		}
    88  	case "plan9":
    89  		for _, e := range env {
    90  			fmt.Printf("%s='%s'\n", e.name, strings.Replace(e.value, "'", "''", -1))
    91  		}
    92  	case "windows":
    93  		for _, e := range env {
    94  			fmt.Printf("set %s=%s\n", e.name, e.value)
    95  		}
    96  	}
    97  }