nix-super/src/libstore/path-info.cc

#include <nlohmann/json.hpp>

#include "path-info.hh"
#include "store-api.hh"
#include "json-utils.hh"
#include "comparator.hh"

namespace nix {

GENERATE_CMP_EXT(
    ,
    std::weak_ordering,
    UnkeyedValidPathInfo,
    me->deriver,
    me->narHash,
    me->references,
    me->registrationTime,
    me->narSize,
    //me->id,
    me->ultimate,
    me->sigs,
    me->ca);

std::string ValidPathInfo::fingerprint(const Store & store) const
{
    if (narSize == 0)
        throw Error("cannot calculate fingerprint of path '%s' because its size is not known",
            store.printStorePath(path));
    return
            "1;" + store.printStorePath(path) + ";"
            + narHash.to_string(HashFormat::Nix32, true) + ";"
            + std::to_string(narSize) + ";"
        + dropEmptyInitThenConcatStringsSep(",", store.printStorePathSet(references));
}


void ValidPathInfo::sign(const Store & store, const Signer & signer)
{
    sigs.insert(signer.signDetached(fingerprint(store)));
}

std::optional<ContentAddressWithReferences> ValidPathInfo::contentAddressWithReferences() const
{
    if (! ca)
        return std::nullopt;

    switch (ca->method.raw) {
        case ContentAddressMethod::Raw::Text:
        {
            assert(references.count(path) == 0);
            return TextInfo {
                .hash = ca->hash,
                .references = references,
            };
        }

        case ContentAddressMethod::Raw::Flat:
        case ContentAddressMethod::Raw::NixArchive:
        case ContentAddressMethod::Raw::Git:
        default:
        {
            auto refs = references;
            bool hasSelfReference = false;
            if (refs.count(path)) {
                hasSelfReference = true;
                refs.erase(path);
            }
            return FixedOutputInfo {
                .method = ca->method.getFileIngestionMethod(),
                .hash = ca->hash,
                .references = {
                    .others = std::move(refs),
                    .self = hasSelfReference,
                },
            };
        }
    }
}

bool ValidPathInfo::isContentAddressed(const Store & store) const
{
    auto fullCaOpt = contentAddressWithReferences();

    if (! fullCaOpt)
        return false;

    auto caPath = store.makeFixedOutputPathFromCA(path.name(), *fullCaOpt);

    bool res = caPath == path;

    if (!res)
        printError("warning: path '%s' claims to be content-addressed but isn't", store.printStorePath(path));

    return res;
}


size_t ValidPathInfo::checkSignatures(const Store & store, const PublicKeys & publicKeys) const
{
    if (isContentAddressed(store)) return maxSigs;

    size_t good = 0;
    for (auto & sig : sigs)
        if (checkSignature(store, publicKeys, sig))
            good++;
    return good;
}


bool ValidPathInfo::checkSignature(const Store & store, const PublicKeys & publicKeys, const std::string & sig) const
{
    return verifyDetached(fingerprint(store), sig, publicKeys);
}


Strings ValidPathInfo::shortRefs() const
{
    Strings refs;
    for (auto & r : references)
        refs.push_back(std::string(r.to_string()));
    return refs;
}

ValidPathInfo::ValidPathInfo(
    const Store & store,
    std::string_view name,
    ContentAddressWithReferences && ca,
    Hash narHash)
      : UnkeyedValidPathInfo(narHash)
      , path(store.makeFixedOutputPathFromCA(name, ca))
{
    this->ca = ContentAddress {
        .method = ca.getMethod(),
        .hash = ca.getHash(),
    };
    std::visit(overloaded {
        [this](TextInfo && ti) {
            this->references = std::move(ti.references);
        },
        [this](FixedOutputInfo && foi) {
            this->references = std::move(foi.references.others);
            if (foi.references.self)
                this->references.insert(path);
        },
    }, std::move(ca).raw);
}


nlohmann::json UnkeyedValidPathInfo::toJSON(
    const Store & store,
    bool includeImpureInfo,
    HashFormat hashFormat) const
{
    using nlohmann::json;

    auto jsonObject = json::object();

    jsonObject["narHash"] = narHash.to_string(hashFormat, true);
    jsonObject["narSize"] = narSize;

    {
        auto & jsonRefs = jsonObject["references"] = json::array();
        for (auto & ref : references)
            jsonRefs.emplace_back(store.printStorePath(ref));
    }

    jsonObject["ca"] = ca ? (std::optional { renderContentAddress(*ca) }) : std::nullopt;

    if (includeImpureInfo) {
        jsonObject["deriver"] = deriver ? (std::optional { store.printStorePath(*deriver) }) : std::nullopt;

        jsonObject["registrationTime"] = registrationTime ? (std::optional { registrationTime }) : std::nullopt;

        jsonObject["ultimate"] = ultimate;

        auto & sigsObj = jsonObject["signatures"] = json::array();
        for (auto & sig : sigs)
            sigsObj.push_back(sig);
    }

    return jsonObject;
}

UnkeyedValidPathInfo UnkeyedValidPathInfo::fromJSON(
    const Store & store,
    const nlohmann::json & _json)
{
    UnkeyedValidPathInfo res {
        Hash(Hash::dummy),
    };

    auto & json = getObject(_json);
    res.narHash = Hash::parseAny(getString(valueAt(json, "narHash")), std::nullopt);
    res.narSize = getInteger(valueAt(json, "narSize"));

    try {
        auto references = getStringList(valueAt(json, "references"));
        for (auto & input : references)
            res.references.insert(store.parseStorePath(static_cast<const std::string &>
(input)));
    } catch (Error & e) {
        e.addTrace({}, "while reading key 'references'");
        throw;
    }

    // New format as this as nullable but mandatory field; handling
    // missing is for back-compat.
    if (json.contains("ca"))
        if (auto * rawCa = getNullable(valueAt(json, "ca")))
            res.ca = ContentAddress::parse(getString(*rawCa));

    if (json.contains("deriver"))
        if (auto * rawDeriver = getNullable(valueAt(json, "deriver")))
            res.deriver = store.parseStorePath(getString(*rawDeriver));

    if (json.contains("registrationTime"))
        if (auto * rawRegistrationTime = getNullable(valueAt(json, "registrationTime")))
            res.registrationTime = getInteger(*rawRegistrationTime);

    if (json.contains("ultimate"))
        res.ultimate = getBoolean(valueAt(json, "ultimate"));

    if (json.contains("signatures"))
        res.sigs = getStringSet(valueAt(json, "signatures"));

    return res;
}

}