github.com/zxy12/go_duplicate_112_new@v0.0.0-20200807091221-747231827200/src/cmd/go/internal/fmtcmd/fmt.go (about)

     1  // Copyright 2011 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 fmtcmd implements the ``go fmt'' command.
     6  package fmtcmd
     7  
     8  import (
     9  	"fmt"
    10  	"os"
    11  	"path/filepath"
    12  	"runtime"
    13  	"strings"
    14  	"sync"
    15  
    16  	"cmd/go/internal/base"
    17  	"cmd/go/internal/cfg"
    18  	"cmd/go/internal/load"
    19  	"cmd/go/internal/modload"
    20  	"cmd/go/internal/str"
    21  )
    22  
    23  func init() {
    24  	base.AddBuildFlagsNX(&CmdFmt.Flag)
    25  }
    26  
    27  var CmdFmt = &base.Command{
    28  	Run:       runFmt,
    29  	UsageLine: "go fmt [-n] [-x] [packages]",
    30  	Short:     "gofmt (reformat) package sources",
    31  	Long: `
    32  Fmt runs the command 'gofmt -l -w' on the packages named
    33  by the import paths. It prints the names of the files that are modified.
    34  
    35  For more about gofmt, see 'go doc cmd/gofmt'.
    36  For more about specifying packages, see 'go help packages'.
    37  
    38  The -n flag prints commands that would be executed.
    39  The -x flag prints commands as they are executed.
    40  
    41  To run gofmt with specific options, run gofmt itself.
    42  
    43  See also: go fix, go vet.
    44  	`,
    45  }
    46  
    47  func runFmt(cmd *base.Command, args []string) {
    48  	printed := false
    49  	gofmt := gofmtPath()
    50  	procs := runtime.GOMAXPROCS(0)
    51  	var wg sync.WaitGroup
    52  	wg.Add(procs)
    53  	fileC := make(chan string, 2*procs)
    54  	for i := 0; i < procs; i++ {
    55  		go func() {
    56  			defer wg.Done()
    57  			for file := range fileC {
    58  				base.Run(str.StringList(gofmt, "-l", "-w", file))
    59  			}
    60  		}()
    61  	}
    62  	for _, pkg := range load.PackagesAndErrors(args) {
    63  		if modload.Enabled() && pkg.Module != nil && !pkg.Module.Main {
    64  			if !printed {
    65  				fmt.Fprintf(os.Stderr, "go: not formatting packages in dependency modules\n")
    66  				printed = true
    67  			}
    68  			continue
    69  		}
    70  		if pkg.Error != nil {
    71  			if strings.HasPrefix(pkg.Error.Err, "build constraints exclude all Go files") {
    72  				// Skip this error, as we will format
    73  				// all files regardless.
    74  			} else {
    75  				base.Errorf("can't load package: %s", pkg.Error)
    76  				continue
    77  			}
    78  		}
    79  		// Use pkg.gofiles instead of pkg.Dir so that
    80  		// the command only applies to this package,
    81  		// not to packages in subdirectories.
    82  		files := base.RelPaths(pkg.InternalAllGoFiles())
    83  		for _, file := range files {
    84  			fileC <- file
    85  		}
    86  	}
    87  	close(fileC)
    88  	wg.Wait()
    89  }
    90  
    91  func gofmtPath() string {
    92  	gofmt := "gofmt"
    93  	if base.ToolIsWindows {
    94  		gofmt += base.ToolWindowsExtension
    95  	}
    96  
    97  	gofmtPath := filepath.Join(cfg.GOBIN, gofmt)
    98  	if _, err := os.Stat(gofmtPath); err == nil {
    99  		return gofmtPath
   100  	}
   101  
   102  	gofmtPath = filepath.Join(cfg.GOROOT, "bin", gofmt)
   103  	if _, err := os.Stat(gofmtPath); err == nil {
   104  		return gofmtPath
   105  	}
   106  
   107  	// fallback to looking for gofmt in $PATH
   108  	return "gofmt"
   109  }