dirhash.go

/*
 * File: dirhash.go
 * Project: mrsign
 * Created Date: Tuesday, October 19th 2021, 12:16:54 pm
 * Authors: Marcello Russo, Fabio Zito
 * -----
 * Last Modified:
 * Modified By:
 * -----
 * MIT License
 *
 * Copyright (c) 2021 MR&&Z
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 * -----
 * HISTORY:
 * Date      	By	Comments
 * ----------	---	----------------------------------------------------------
 */

package main

import (
	"crypto/sha256"
	"encoding/base64"
	"fmt"
	"io"
	"log"
	"os"
	"path/filepath"
	"sort"
	"strings"
)

type Hash func(files []string, open func(string) (io.ReadCloser, error)) (string, error)

func Hash256(files []string, open func(string) (io.ReadCloser, error)) (string, error) {
	h := sha256.New()
	files = append([]string(nil), files...)
	sort.Strings(files)
	for _, file := range files {
		if strings.Contains(file, "\n") {
			log.Print("dirhash: filenames with newlines are not supported")
			continue
		}
		r, err := open(file)
		if err != nil {
			return "", err
		}
		hf := sha256.New()
		_, err = io.Copy(hf, r)
		_ = r.Close()
		if err != nil {
			return "", err
		}
		_, _ = fmt.Fprintf(h, "%x  %s\n", hf.Sum(nil), file)
	}
	return "h1:" + base64.StdEncoding.EncodeToString(h.Sum(nil)), nil
}

func HashDir(dir string, prefix string, exclude []string, hash Hash) (string, error) {
	e := make(map[string]bool)
	for _, l := range exclude {
		e[l] = true
	}
	files, err := DirFiles(dir, prefix, e)
	if err != nil {
		return "", err
	}
	osOpen := func(name string) (io.ReadCloser, error) {
		return os.Open(filepath.Join(dir, strings.TrimPrefix(name, prefix)))
	}
	return hash(files, osOpen)
}

func DirFiles(dir string, prefix string, e map[string]bool) ([]string, error) {
	var files []string
	dir = filepath.Clean(dir)
	err := filepath.Walk(dir, func(file string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if info.IsDir() {
			return nil
		}
		if _, ok := e[info.Name()]; ok {
			return nil
		}
		rel := file
		if dir != "." {
			rel = file[len(dir)+1:]
		}
		f := filepath.Join(prefix, rel)
		files = append(files, filepath.ToSlash(f))

		//fmt.Println("adding ", filepath.ToSlash(f))
		return nil
	})
	if err != nil {
		return nil, err
	}
	return files, nil
}