path: root/third_party/nix/src/nix/hash.cc

#include "libutil/hash.hh"

#include "libmain/shared.hh"
#include "nix/command.hh"
#include "nix/legacy.hh"

using namespace nix;

struct CmdHash final : Command {
  enum Mode { mFile, mPath };
  Mode mode;
  Base base = SRI;
  bool truncate = false;
  HashType ht = htSHA256;
  std::vector<std::string> paths;

  explicit CmdHash(Mode mode) : mode(mode) {
    mkFlag(0, "sri", "print hash in SRI format", &base, SRI);
    mkFlag(0, "base64", "print hash in base-64", &base, Base64);
    mkFlag(0, "base32", "print hash in base-32 (Nix-specific)", &base, Base32);
    mkFlag(0, "base16", "print hash in base-16", &base, Base16);
    mkFlag().longName("type").mkHashTypeFlag(&ht);
    expectArgs("paths", &paths);
  }

  std::string name() override {
    return mode == mFile ? "hash-file" : "hash-path";
  }

  std::string description() override {
    return mode == mFile
               ? "print cryptographic hash of a regular file"
               : "print cryptographic hash of the NAR serialisation of a path";
  }

  void run() override {
    for (const auto& path : paths) {
      Hash h = mode == mFile ? hashFile(ht, path) : hashPath(ht, path).first;
      if (truncate && h.hashSize > 20) {
        h = compressHash(h, 20);
      }
      std::cout << format("%1%\n") % h.to_string(base, base == SRI);
    }
  }
};

static RegisterCommand r1(make_ref<CmdHash>(CmdHash::mFile));
static RegisterCommand r2(make_ref<CmdHash>(CmdHash::mPath));

struct CmdToBase final : Command {
  Base base;
  HashType ht = htUnknown;
  std::vector<std::string> args;

  explicit CmdToBase(Base base) : base(base) {
    mkFlag().longName("type").mkHashTypeFlag(&ht);
    expectArgs("strings", &args);
  }

  std::string name() override {
    return base == Base16
               ? "to-base16"
               : base == Base32 ? "to-base32"
                                : base == Base64 ? "to-base64" : "to-sri";
  }

  std::string description() override {
    return fmt(
        "convert a hash to %s representation",
        base == Base16
            ? "base-16"
            : base == Base32 ? "base-32" : base == Base64 ? "base-64" : "SRI");
  }

  void run() override {
    for (const auto& s : args) {
      auto hash_ = Hash::deserialize(s, ht);
      if (hash_.ok()) {
        std::cout << hash_->to_string(base, base == SRI) << "\n";
      } else {
        std::cerr << "failed to parse: " << hash_.status().ToString() << "\n";
        // create a matching blank line, for scripting
        std::cout << "\n";
      }
    }
  }
};

static RegisterCommand r3(make_ref<CmdToBase>(Base16));
static RegisterCommand r4(make_ref<CmdToBase>(Base32));
static RegisterCommand r5(make_ref<CmdToBase>(Base64));
static RegisterCommand r6(make_ref<CmdToBase>(SRI));

/* Legacy nix-hash command. */
static int compatNixHash(int argc, char** argv) {
  HashType ht = htMD5;
  bool flat = false;
  bool base32 = false;
  bool truncate = false;
  enum { opHash, opTo32, opTo16 } op = opHash;
  std::vector<std::string> ss;

  parseCmdLine(argc, argv,
               [&](Strings::iterator& arg, const Strings::iterator& end) {
                 if (*arg == "--help") {
                   showManPage("nix-hash");
                 } else if (*arg == "--version") {
                   printVersion("nix-hash");
                 } else if (*arg == "--flat") {
                   flat = true;
                 } else if (*arg == "--base32") {
                   base32 = true;
                 } else if (*arg == "--truncate") {
                   truncate = true;
                 } else if (*arg == "--type") {
                   std::string s = getArg(*arg, arg, end);
                   ht = parseHashType(s);
                   if (ht == htUnknown) {
                     throw UsageError(format("unknown hash type '%1%'") % s);
                   }
                 } else if (*arg == "--to-base16") {
                   op = opTo16;
                 } else if (*arg == "--to-base32") {
                   op = opTo32;
                 } else if (*arg != "" && arg->at(0) == '-') {
                   return false;
                 } else {
                   ss.push_back(*arg);
                 }
                 return true;
               });

  if (op == opHash) {
    CmdHash cmd(flat ? CmdHash::mFile : CmdHash::mPath);
    cmd.ht = ht;
    cmd.base = base32 ? Base32 : Base16;
    cmd.truncate = truncate;
    cmd.paths = ss;
    cmd.run();
  }

  else {
    CmdToBase cmd(op == opTo32 ? Base32 : Base16);
    cmd.args = ss;
    cmd.ht = ht;
    cmd.run();
  }

  return 0;
}

static RegisterLegacyCommand s1("nix-hash", compatNixHash);