werf/werf

package util

import (
    "crypto/sha256"
    "fmt"
    "io"
    "os"
    "path/filepath"
    "strings"

    "github.com/spaolacci/murmur3"
    "golang.org/x/crypto/sha3"
    "golang.org/x/mod/sumdb/dirhash"
)

// LegacyMurmurHash function returns a hash of non-fixed length (1-8 symbols)
func LegacyMurmurHash(args ...string) string {
    h32 := murmur3.New32()
    h32.Write([]byte(prepareHashArgs(args...)))
    sum := h32.Sum32()
    return fmt.Sprintf("%x", sum)

    // TODO: use byte slice instead of uint32
    // bytes := (*[4]byte)(unsafe.Pointer(&sum))
    // return fmt.Sprintf("%x", *bytes)
}

func Sha3_224Hash(args ...string) string {
    sum := sha3.Sum224([]byte(prepareHashArgs(args...)))
    return fmt.Sprintf("%x", sum)
}

func Sha256Hash(args ...string) string {
    sum := sha256.Sum256([]byte(prepareHashArgs(args...)))
    return fmt.Sprintf("%x", sum)
}

// For file: hash contents of file with its name.
// For directory: hash contents of all files in directory, along with their relative filenames.
func HashContentsAndPathsRecurse(path string) (string, error) {
    path = filepath.Clean(path)

    fi, err := os.Stat(path)
    if err != nil {
        return "", fmt.Errorf("unable to stat %q: %w", path, err)
    }

    var hash string
    if fi.IsDir() {
        if hash, err = dirhash.HashDir(path, "/", dirhash.Hash1); err != nil {
            return "", fmt.Errorf("unable to calculate hash for dir %q: %w", path, err)
        }
    } else {
        if hash, err = dirhash.Hash1([]string{filepath.Base(path)}, func(_ string) (io.ReadCloser, error) {
            return os.Open(path)
        }); err != nil {
            return "", fmt.Errorf("unable to calculate hash for file %q: %w", path, err)
        }
    }

    return hash, nil
}

func prepareHashArgs(args ...string) string {
    return strings.Join(args, ":::")
}