headscan.go

     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  //go:build ignore
     6  
     7  /*
     8  	The headscan command extracts comment headings from package files;
     9  	it is used to detect false positives which may require an adjustment
    10  	to the comment formatting heuristics in comment.go.
    11  
    12  	Usage: headscan [-root root_directory]
    13  
    14  	By default, the $GOROOT/src directory is scanned.
    15  */
    16  package main
    17  
    18  import (
    19  	"bytes"
    20  	"flag"
    21  	"fmt"
    22  	"go/doc"
    23  	"go/parser"
    24  	"go/token"
    25  	"io/fs"
    26  	"os"
    27  	"path/filepath"
    28  	"regexp"
    29  	"runtime"
    30  	"strings"
    31  )
    32  
    33  var (
    34  	root    = flag.String("root", filepath.Join(runtime.GOROOT(), "src"), "root of filesystem tree to scan")
    35  	verbose = flag.Bool("v", false, "verbose mode")
    36  )
    37  
    38  // ToHTML in comment.go assigns a (possibly blank) ID to each heading
    39  var html_h = regexp.MustCompile(`<h3 id="[^"]*">`)
    40  
    41  const html_endh = "</h3>\n"
    42  
    43  func isGoFile(fi fs.FileInfo) bool {
    44  	return strings.HasSuffix(fi.Name(), ".go") &&
    45  		!strings.HasSuffix(fi.Name(), "_test.go")
    46  }
    47  
    48  func appendHeadings(list []string, comment string) []string {
    49  	var buf bytes.Buffer
    50  	doc.ToHTML(&buf, comment, nil)
    51  	for s := buf.String(); s != ""; {
    52  		loc := html_h.FindStringIndex(s)
    53  		if len(loc) == 0 {
    54  			break
    55  		}
    56  		var inner string
    57  		inner, s, _ = strings.Cut(s[loc[1]:], html_endh)
    58  		list = append(list, inner)
    59  	}
    60  	return list
    61  }
    62  
    63  func main() {
    64  	flag.Parse()
    65  	fset := token.NewFileSet()
    66  	nheadings := 0
    67  	err := filepath.WalkDir(*root, func(path string, info fs.DirEntry, err error) error {
    68  		if !info.IsDir() {
    69  			return nil
    70  		}
    71  		pkgs, err := parser.ParseDir(fset, path, isGoFile, parser.ParseComments)
    72  		if err != nil {
    73  			if *verbose {
    74  				fmt.Fprintln(os.Stderr, err)
    75  			}
    76  			return nil
    77  		}
    78  		for _, pkg := range pkgs {
    79  			d := doc.New(pkg, path, doc.Mode(0))
    80  			list := appendHeadings(nil, d.Doc)
    81  			for _, d := range d.Consts {
    82  				list = appendHeadings(list, d.Doc)
    83  			}
    84  			for _, d := range d.Types {
    85  				list = appendHeadings(list, d.Doc)
    86  			}
    87  			for _, d := range d.Vars {
    88  				list = appendHeadings(list, d.Doc)
    89  			}
    90  			for _, d := range d.Funcs {
    91  				list = appendHeadings(list, d.Doc)
    92  			}
    93  			if len(list) > 0 {
    94  				// directories may contain multiple packages;
    95  				// print path and package name
    96  				fmt.Printf("%s (package %s)\n", path, pkg.Name)
    97  				for _, h := range list {
    98  					fmt.Printf("\t%s\n", h)
    99  				}
   100  				nheadings += len(list)
   101  			}
   102  		}
   103  		return nil
   104  	})
   105  	if err != nil {
   106  		fmt.Fprintln(os.Stderr, err)
   107  		os.Exit(1)
   108  	}
   109  	fmt.Println(nheadings, "headings found")
   110  }
   111
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