copyright.go

Documentation: golang.org/x/tools/copyright

     1  // Copyright 2020 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 copyright checks that files have the correct copyright notices.
     6  package copyright
     7  
     8  import (
     9  	"go/ast"
    10  	"go/parser"
    11  	"go/token"
    12  	"io/fs"
    13  	"os"
    14  	"path/filepath"
    15  	"regexp"
    16  	"strings"
    17  )
    18  
    19  func checkCopyright(dir string) ([]string, error) {
    20  	var files []string
    21  	err := filepath.WalkDir(dir, func(path string, d fs.DirEntry, err error) error {
    22  		if err != nil {
    23  			return err
    24  		}
    25  		if d.IsDir() {
    26  			// Skip directories like ".git".
    27  			if strings.HasPrefix(d.Name(), ".") {
    28  				return filepath.SkipDir
    29  			}
    30  			// Skip any directory that starts with an underscore, as the go
    31  			// command would.
    32  			if strings.HasPrefix(d.Name(), "_") {
    33  				return filepath.SkipDir
    34  			}
    35  			return nil
    36  		}
    37  		needsCopyright, err := checkFile(dir, path)
    38  		if err != nil {
    39  			return err
    40  		}
    41  		if needsCopyright {
    42  			files = append(files, path)
    43  		}
    44  		return nil
    45  	})
    46  	return files, err
    47  }
    48  
    49  var copyrightRe = regexp.MustCompile(`Copyright \d{4} The Go Authors. All rights reserved.
    50  Use of this source code is governed by a BSD-style
    51  license that can be found in the LICENSE file.`)
    52  
    53  func checkFile(toolsDir, filename string) (bool, error) {
    54  	// Only check Go files.
    55  	if !strings.HasSuffix(filename, "go") {
    56  		return false, nil
    57  	}
    58  	// Don't check testdata files.
    59  	normalized := strings.TrimPrefix(filepath.ToSlash(filename), filepath.ToSlash(toolsDir))
    60  	if strings.Contains(normalized, "/testdata/") {
    61  		return false, nil
    62  	}
    63  	// goyacc is the only file with a different copyright header.
    64  	if strings.HasSuffix(normalized, "cmd/goyacc/yacc.go") {
    65  		return false, nil
    66  	}
    67  	content, err := os.ReadFile(filename)
    68  	if err != nil {
    69  		return false, err
    70  	}
    71  	fset := token.NewFileSet()
    72  	parsed, err := parser.ParseFile(fset, filename, content, parser.ParseComments)
    73  	if err != nil {
    74  		return false, err
    75  	}
    76  	// Don't require headers on generated files.
    77  	if isGenerated(fset, parsed) {
    78  		return false, nil
    79  	}
    80  	shouldAddCopyright := true
    81  	for _, c := range parsed.Comments {
    82  		// The copyright should appear before the package declaration.
    83  		if c.Pos() > parsed.Package {
    84  			break
    85  		}
    86  		if copyrightRe.MatchString(c.Text()) {
    87  			shouldAddCopyright = false
    88  			break
    89  		}
    90  	}
    91  	return shouldAddCopyright, nil
    92  }
    93  
    94  // Copied from golang.org/x/tools/gopls/internal/golang/util.go.
    95  // Matches cgo generated comment as well as the proposed standard:
    96  //
    97  //	https://golang.org/s/generatedcode
    98  var generatedRx = regexp.MustCompile(`// .*DO NOT EDIT\.?`)
    99  
   100  func isGenerated(fset *token.FileSet, file *ast.File) bool {
   101  	for _, commentGroup := range file.Comments {
   102  		for _, comment := range commentGroup.List {
   103  			if matched := generatedRx.MatchString(comment.Text); !matched {
   104  				continue
   105  			}
   106  			// Check if comment is at the beginning of the line in source.
   107  			if pos := fset.Position(comment.Slash); pos.Column == 1 {
   108  				return true
   109  			}
   110  		}
   111  	}
   112  	return false
   113  }
   114
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