lix/src/libstore/path-info.hh

#pragma once
///@file

#include "crypto.hh"
#include "path.hh"
#include "hash.hh"
#include "content-address.hh"

#include <string>
#include <optional>

namespace nix {


class Store;


struct SubstitutablePathInfo
{
    std::optional<StorePath> deriver;
    StorePathSet references;
    /**
     * 0 = unknown or inapplicable
     */
    uint64_t downloadSize;
    /**
     * 0 = unknown
     */
    uint64_t narSize;
};

typedef std::map<StorePath, SubstitutablePathInfo> SubstitutablePathInfos;


struct ValidPathInfo
{
    StorePath path;
    std::optional<StorePath> deriver;
    /**
     * \todo document this
     */
    Hash narHash;
    StorePathSet references;
    time_t registrationTime = 0;
    uint64_t narSize = 0; // 0 = unknown
    uint64_t id; // internal use only

    /**
     * Whether the path is ultimately trusted, that is, it's a
     * derivation output that was built locally.
     */
    bool ultimate = false;

    StringSet sigs; // note: not necessarily verified

    /**
     * If non-empty, an assertion that the path is content-addressed,
     * i.e., that the store path is computed from a cryptographic hash
     * of the contents of the path, plus some other bits of data like
     * the "name" part of the path. Such a path doesn't need
     * signatures, since we don't have to trust anybody's claim that
     * the path is the output of a particular derivation. (In the
     * extensional store model, we have to trust that the *contents*
     * of an output path of a derivation were actually produced by
     * that derivation. In the intensional model, we have to trust
     * that a particular output path was produced by a derivation; the
     * path then implies the contents.)
     *
     * Ideally, the content-addressability assertion would just be a Boolean,
     * and the store path would be computed from the name component, ‘narHash’
     * and ‘references’. However, we support many types of content addresses.
     */
    std::optional<ContentAddress> ca;

    bool operator == (const ValidPathInfo & i) const
    {
        return
            path == i.path
            && narHash == i.narHash
            && references == i.references;
    }

    /**
     * Return a fingerprint of the store path to be used in binary
     * cache signatures. It contains the store path, the base-32
     * SHA-256 hash of the NAR serialisation of the path, the size of
     * the NAR, and the sorted references. The size field is strictly
     * speaking superfluous, but might prevent endless/excessive data
     * attacks.
     */
    std::string fingerprint(const Store & store) const;

    void sign(const Store & store, const SecretKey & secretKey);

    /**
     * @return true iff the path is verifiably content-addressed.
     */
    bool isContentAddressed(const Store & store) const;

    static const size_t maxSigs = std::numeric_limits<size_t>::max();

    /**
     * Return the number of signatures on this .narinfo that were
     * produced by one of the specified keys, or maxSigs if the path
     * is content-addressed.
     */
    size_t checkSignatures(const Store & store, const PublicKeys & publicKeys) const;

    /**
     * Verify a single signature.
     */
    bool checkSignature(const Store & store, const PublicKeys & publicKeys, const std::string & sig) const;

    Strings shortRefs() const;

    ValidPathInfo(const ValidPathInfo & other) = default;

    ValidPathInfo(StorePath && path, Hash narHash) : path(std::move(path)), narHash(narHash) { };
    ValidPathInfo(const StorePath & path, Hash narHash) : path(path), narHash(narHash) { };

    virtual ~ValidPathInfo() { }

    static ValidPathInfo read(Source & source, const Store & store, unsigned int format);
    static ValidPathInfo read(Source & source, const Store & store, unsigned int format, StorePath && path);

    void write(Sink & sink, const Store & store, unsigned int format, bool includePath = true) const;
};

typedef std::map<StorePath, ValidPathInfo> ValidPathInfos;

}