nix/src/libstore/nar-info-disk-cache.cc

#include "nar-info-disk-cache.hh"
#include "sync.hh"
#include "sqlite.hh"
#include "globals.hh"

#include <sqlite3.h>

namespace nix {

static const char * schema = R"sql(

create table if not exists BinaryCaches (
    id        integer primary key autoincrement not null,
    url       text unique not null,
    timestamp integer not null,
    storeDir  text not null,
    wantMassQuery integer not null,
    priority  integer not null
);

create table if not exists NARs (
    cache            integer not null,
    storePath        text not null,
    url              text,
    compression      text,
    fileHash         text,
    fileSize         integer,
    narHash          text,
    narSize          integer,
    refs             text,
    deriver          text,
    sigs             text,
    timestamp        integer not null,
    primary key (cache, storePath),
    foreign key (cache) references BinaryCaches(id) on delete cascade
);

create table if not exists NARExistence (
    cache            integer not null,
    storePath        text not null,
    exist            integer not null,
    timestamp        integer not null,
    primary key (cache, storePath),
    foreign key (cache) references BinaryCaches(id) on delete cascade
);

)sql";

class NarInfoDiskCacheImpl : public NarInfoDiskCache
{
public:

    /* How long negative lookups are valid. */
    const int ttlNegative = 3600;

    struct State
    {
        SQLite db;
        SQLiteStmt insertCache, queryCache, insertNAR, queryNAR, insertNARExistence, queryNARExistence;
        std::map<std::string, int> caches;
    };

    Sync<State> _state;

    NarInfoDiskCacheImpl()
    {
        auto state(_state.lock());

        Path dbPath = getCacheDir() + "/nix/binary-cache-v3.sqlite";
        createDirs(dirOf(dbPath));

        if (sqlite3_open_v2(dbPath.c_str(), &state->db.db,
                SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE, 0) != SQLITE_OK)
            throw Error(format("cannot open store cache ‘%s’") % dbPath);

        if (sqlite3_busy_timeout(state->db, 60 * 60 * 1000) != SQLITE_OK)
            throwSQLiteError(state->db, "setting timeout");

        // We can always reproduce the cache.
        if (sqlite3_exec(state->db, "pragma synchronous = off", 0, 0, 0) != SQLITE_OK)
            throwSQLiteError(state->db, "making database asynchronous");
        if (sqlite3_exec(state->db, "pragma main.journal_mode = truncate", 0, 0, 0) != SQLITE_OK)
            throwSQLiteError(state->db, "setting journal mode");

        if (sqlite3_exec(state->db, schema, 0, 0, 0) != SQLITE_OK)
            throwSQLiteError(state->db, "initialising database schema");

        state->insertCache.create(state->db,
            "insert or replace into BinaryCaches(url, timestamp, storeDir, wantMassQuery, priority) values (?, ?, ?, ?, ?)");

        state->queryCache.create(state->db,
            "select id, storeDir, wantMassQuery, priority from BinaryCaches where url = ?");

        state->insertNAR.create(state->db,
            "insert or replace into NARs(cache, storePath, url, compression, fileHash, fileSize, narHash, "
            "narSize, refs, deriver, sigs, timestamp) values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");

        state->queryNAR.create(state->db,
            "select * from NARs where cache = ? and storePath = ?");

        state->insertNARExistence.create(state->db,
            "insert or replace into NARExistence(cache, storePath, exist, timestamp) values (?, ?, ?, ?)");

        state->queryNARExistence.create(state->db,
            "select exist, timestamp from NARExistence where cache = ? and storePath = ?");
    }

    int uriToInt(State & state, const std::string & uri)
    {
        auto i = state.caches.find(uri);
        if (i == state.caches.end()) abort();
        return i->second;
    }

    void createCache(const std::string & uri) override
    {
        auto state(_state.lock());

        // FIXME: race

        state->insertCache.use()(uri)(time(0))(settings.nixStore)(1)(0).exec();
        assert(sqlite3_changes(state->db) == 1);
        state->caches[uri] = sqlite3_last_insert_rowid(state->db);
    }

    bool cacheExists(const std::string & uri) override
    {
        auto state(_state.lock());

        auto i = state->caches.find(uri);
        if (i != state->caches.end()) return true;

        auto queryCache(state->queryCache.use()(uri));

        if (queryCache.next()) {
            state->caches[uri] = queryCache.getInt(0);
            return true;
        }

        return false;
    }

    std::pair<Outcome, std::shared_ptr<NarInfo>> lookupNarInfo(
        const std::string & uri, const Path & storePath) override
    {
        auto state(_state.lock());

        auto queryNAR(state->queryNAR.use()
            (uriToInt(*state, uri))
            (baseNameOf(storePath)));

        if (!queryNAR.next())
            // FIXME: check NARExistence
            return {oUnknown, 0};

        auto narInfo = make_ref<NarInfo>();

        // FIXME: implement TTL.

        narInfo->path = storePath;
        narInfo->url = queryNAR.getStr(2);
        narInfo->compression = queryNAR.getStr(3);
        if (!queryNAR.isNull(4))
            narInfo->fileHash = parseHash(queryNAR.getStr(4));
        narInfo->fileSize = queryNAR.getInt(5);
        narInfo->narHash = parseHash(queryNAR.getStr(6));
        narInfo->narSize = queryNAR.getInt(7);
        for (auto & r : tokenizeString<Strings>(queryNAR.getStr(8), " "))
            narInfo->references.insert(settings.nixStore + "/" + r);
        if (!queryNAR.isNull(9))
            narInfo->deriver = settings.nixStore + "/" + queryNAR.getStr(9);
        for (auto & sig : tokenizeString<Strings>(queryNAR.getStr(10), " "))
            narInfo->sigs.insert(sig);

        return {oValid, narInfo};
    }

    void upsertNarInfo(
        const std::string & uri, std::shared_ptr<ValidPathInfo> info) override
    {
        auto state(_state.lock());

        if (info) {

            auto narInfo = std::dynamic_pointer_cast<NarInfo>(info);

            state->insertNAR.use()
                (uriToInt(*state, uri))
                (baseNameOf(info->path))
                (narInfo ? narInfo->url : "", narInfo != 0)
                (narInfo ? narInfo->compression : "", narInfo != 0)
                (narInfo && narInfo->fileHash ? narInfo->fileHash.to_string() : "", narInfo && narInfo->fileHash)
                (narInfo ? narInfo->fileSize : 0, narInfo != 0 && narInfo->fileSize)
                (info->narHash.to_string())
                (info->narSize)
                (concatStringsSep(" ", info->shortRefs()))
                (info->deriver != "" ? baseNameOf(info->deriver) : "", info->deriver != "")
                (concatStringsSep(" ", info->sigs))
                (time(0)).exec();

        } else {
            // not implemented
            abort();
        }
    }
};

ref<NarInfoDiskCache> getNarInfoDiskCache()
{
    static Sync<std::shared_ptr<NarInfoDiskCache>> cache;

    auto cache_(cache.lock());
    if (!*cache_) *cache_ = std::make_shared<NarInfoDiskCacheImpl>();
    return ref<NarInfoDiskCache>(*cache_);
}

}