lix/src/nix/hash.cc
Eelco Dolstra b2d6c6161e Move 'nix hash-*' and 'nix to-*' to 'nix hash'
From the 'nix' UX review.
2020-12-03 17:55:55 +01:00

195 lines
5.5 KiB
C++

#include "command.hh"
#include "hash.hh"
#include "content-address.hh"
#include "legacy.hh"
#include "shared.hh"
#include "references.hh"
#include "archive.hh"
using namespace nix;
struct CmdHashBase : Command
{
FileIngestionMethod mode;
Base base = SRI;
bool truncate = false;
HashType ht = htSHA256;
std::vector<std::string> paths;
std::optional<std::string> modulus;
CmdHashBase(FileIngestionMethod 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);
addFlag(Flag::mkHashTypeFlag("type", &ht));
#if 0
mkFlag()
.longName("modulo")
.description("compute hash modulo specified string")
.labels({"modulus"})
.dest(&modulus);
#endif
expectArgs({
.label = "paths",
.handler = {&paths},
.completer = completePath
});
}
std::string description() override
{
const char* d;
switch (mode) {
case FileIngestionMethod::Flat:
d = "print cryptographic hash of a regular file";
break;
case FileIngestionMethod::Recursive:
d = "print cryptographic hash of the NAR serialisation of a path";
};
return d;
}
void run() override
{
for (auto path : paths) {
std::unique_ptr<AbstractHashSink> hashSink;
if (modulus)
hashSink = std::make_unique<HashModuloSink>(ht, *modulus);
else
hashSink = std::make_unique<HashSink>(ht);
switch (mode) {
case FileIngestionMethod::Flat:
readFile(path, *hashSink);
break;
case FileIngestionMethod::Recursive:
dumpPath(path, *hashSink);
break;
}
Hash h = hashSink->finish().first;
if (truncate && h.hashSize > 20) h = compressHash(h, 20);
logger->cout(h.to_string(base, base == SRI));
}
}
};
struct CmdToBase : Command
{
Base base;
std::optional<HashType> ht;
std::vector<std::string> args;
CmdToBase(Base base) : base(base)
{
addFlag(Flag::mkHashTypeOptFlag("type", &ht));
expectArgs("strings", &args);
}
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 (auto s : args)
logger->cout(Hash::parseAny(s, ht).to_string(base, base == SRI));
}
};
struct CmdHash : NixMultiCommand
{
CmdHash()
: MultiCommand({
{"file", []() { return make_ref<CmdHashBase>(FileIngestionMethod::Flat);; }},
{"path", []() { return make_ref<CmdHashBase>(FileIngestionMethod::Recursive); }},
{"to-base16", []() { return make_ref<CmdToBase>(Base16); }},
{"to-base32", []() { return make_ref<CmdToBase>(Base32); }},
{"to-base64", []() { return make_ref<CmdToBase>(Base64); }},
{"to-sri", []() { return make_ref<CmdToBase>(SRI); }},
})
{ }
std::string description() override
{
return "compute and convert cryptographic hashes";
}
Category category() override { return catUtility; }
void run() override
{
if (!command)
throw UsageError("'nix hash' requires a sub-command.");
command->second->prepare();
command->second->run();
}
void printHelp(const string & programName, std::ostream & out) override
{
MultiCommand::printHelp(programName, out);
}
};
static auto rCmdHash = registerCommand<CmdHash>("hash");
/* 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") {
string s = getArg(*arg, arg, end);
ht = parseHashType(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) {
CmdHashBase cmd(flat ? FileIngestionMethod::Flat : FileIngestionMethod::Recursive);
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 r_nix_hash("nix-hash", compatNixHash);