mkzip.go

     1  // Copyright 2022 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  // Mkzip writes a zoneinfo.zip with the content of the current directory
     8  // and its subdirectories, with no compression, suitable for package time.
     9  //
    10  // Usage:
    11  //
    12  //	go run ../../mkzip.go ../../zoneinfo.zip
    13  //
    14  // We use this program instead of 'zip -0 -r ../../zoneinfo.zip *' to get
    15  // a reproducible generator that does not depend on which version of the
    16  // external zip tool is used or the ordering of file names in a directory
    17  // or the current time.
    18  package main
    19  
    20  import (
    21  	"archive/zip"
    22  	"bytes"
    23  	"flag"
    24  	"fmt"
    25  	"hash/crc32"
    26  	"io/fs"
    27  	"log"
    28  	"os"
    29  	"path/filepath"
    30  	"strings"
    31  )
    32  
    33  func usage() {
    34  	fmt.Fprintf(os.Stderr, "usage: go run mkzip.go ../../zoneinfo.zip\n")
    35  	os.Exit(2)
    36  }
    37  
    38  func main() {
    39  	log.SetPrefix("mkzip: ")
    40  	log.SetFlags(0)
    41  	flag.Usage = usage
    42  	flag.Parse()
    43  	args := flag.Args()
    44  	if len(args) != 1 || !strings.HasSuffix(args[0], ".zip") {
    45  		usage()
    46  	}
    47  
    48  	var zb bytes.Buffer
    49  	zw := zip.NewWriter(&zb)
    50  	seen := make(map[string]bool)
    51  	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
    52  		if d.IsDir() {
    53  			return nil
    54  		}
    55  		data, err := os.ReadFile(path)
    56  		if err != nil {
    57  			log.Fatal(err)
    58  		}
    59  		if strings.HasSuffix(path, ".zip") {
    60  			log.Fatalf("unexpected file during walk: %s", path)
    61  		}
    62  		name := filepath.ToSlash(path)
    63  		w, err := zw.CreateRaw(&zip.FileHeader{
    64  			Name:               name,
    65  			Method:             zip.Store,
    66  			CompressedSize64:   uint64(len(data)),
    67  			UncompressedSize64: uint64(len(data)),
    68  			CRC32:              crc32.ChecksumIEEE(data),
    69  		})
    70  		if err != nil {
    71  			log.Fatal(err)
    72  		}
    73  		if _, err := w.Write(data); err != nil {
    74  			log.Fatal(err)
    75  		}
    76  		seen[name] = true
    77  		return nil
    78  	})
    79  	if err != nil {
    80  		log.Fatal(err)
    81  	}
    82  	if err := zw.Close(); err != nil {
    83  		log.Fatal(err)
    84  	}
    85  	if len(seen) == 0 {
    86  		log.Fatalf("did not find any files to add")
    87  	}
    88  	if !seen["US/Eastern"] {
    89  		log.Fatalf("did not find US/Eastern to add")
    90  	}
    91  	if err := os.WriteFile(args[0], zb.Bytes(), 0666); err != nil {
    92  		log.Fatal(err)
    93  	}
    94  }
    95
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