#include "nix/cmd/command.hh"

#include "nix/store/store-api.hh"

#include "nix/util/archive.hh"

#include "nix/util/nar-accessor.hh"

#include "nix/util/serialise.hh"

#include "nix/util/source-accessor.hh"

#include <nlohmann/json.hpp>

using namespace nix;

struct MixCat : virtual Args

{

void cat(ref<SourceAccessor> accessor, CanonPath path)

{

auto st = accessor->lstat(path);

if (st.type != SourceAccessor::Type::tRegular)

throw Error("path '%1%' is not a regular file", path.abs());

logger->stop();

writeFull(getStandardOutput(), accessor->readFile(path));

}

};

struct CmdCatStore : StoreCommand, MixCat

{

std::string path;

CmdCatStore()

{

expectArgs({.label = "path", .handler = {&path}, .completer = completePath});

}

std::string description() override

{

return "print the contents of a file in the Nix store on stdout";

}

std::string doc() override

{

return

#include "store-cat.md"

;

}

void run(ref<Store> store) override

{

auto [storePath, rest] = store->toStorePath(path);

cat(store->requireStoreObjectAccessor(storePath), CanonPath{rest});

}

};

struct CmdCatNar : StoreCommand, MixCat

{

Path narPath;

std::string path;

CmdCatNar()

{

expectArgs({.label = "nar", .handler = {&narPath}, .completer = completePath});

expectArg("path", &path);

}

std::string description() override

{

return "print the contents of a file inside a NAR file on stdout";

}

std::string doc() override

{

return

#include "nar-cat.md"

;

}

void run(ref<Store> store) override

{

AutoCloseFD fd = toDescriptor(open(narPath.c_str(), O_RDONLY));

if (!fd)

throw SysError("opening NAR file '%s'", narPath);

auto source = FdSource{fd.get()};

struct CatRegularFileSink : NullFileSystemObjectSink

{

CanonPath neededPath = CanonPath::root;

bool found = false;

void createRegularFile(const CanonPath & path, std::function<void(CreateRegularFileSink &)> crf) override

{

struct : CreateRegularFileSink, FdSink

{

void isExecutable() override {}

} crfSink;

crfSink.fd = INVALID_DESCRIPTOR;

if (path == neededPath) {

logger->stop();

crfSink.skipContents = false;

crfSink.fd = getStandardOutput();

found = true;

} else {

crfSink.skipContents = true;

}

crf(crfSink);

}

} sink;

sink.neededPath = CanonPath(path);

/* NOTE: We still parse the whole file to validate that it's a correct NAR. */

parseDump(sink, source);

if (!sink.found)

throw Error("NAR does not contain regular file '%1%'", path);

}

};

static auto rCmdCatStore = registerCommand2<CmdCatStore>({"store", "cat"});

static auto rCmdCatNar = registerCommand2<CmdCatNar>({"nar", "cat"});