Use `enum struct` and drop prefixes

This does a few enums; the rest will be gotten in subsequent commits.

21 files changed, 149 insertions, 134 deletions

diff --git a/src/libstore/binary-cache-store.cc b/src/libstore/binary-cache-store.cc
index 3a2d84861..a650bbfa6 100644
--- a/src/libstore/binary-cache-store.cc
+++ b/src/libstore/binary-cache-store.cc
@@ -134,7 +134,7 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, const ref<std::str
     auto narInfo = make_ref<NarInfo>(info);
 
     narInfo->narSize = nar->size();
-    narInfo->narHash = hashString(htSHA256, *nar);
+    narInfo->narHash = hashString(HashType::SHA256, *nar);
 
     if (info.narHash && info.narHash != narInfo->narHash)
         throw Error("refusing to copy corrupted path '%1%' to binary cache", printStorePath(info.path));
@@ -169,16 +169,16 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, const ref<std::str
     auto now1 = std::chrono::steady_clock::now();
     auto narCompressed = compress(compression, *nar, parallelCompression);
     auto now2 = std::chrono::steady_clock::now();
-    narInfo->fileHash = hashString(htSHA256, *narCompressed);
+    narInfo->fileHash = hashString(HashType::SHA256, *narCompressed);
     narInfo->fileSize = narCompressed->size();
 
     auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(now2 - now1).count();
-    printMsg(lvlTalkative, "copying path '%1%' (%2% bytes, compressed %3$.1f%% in %4% ms) to binary cache",
+    printMsg(Verbosity::Talkative, "copying path '%1%' (%2% bytes, compressed %3$.1f%% in %4% ms) to binary cache",
         printStorePath(narInfo->path), narInfo->narSize,
         ((1.0 - (double) narCompressed->size() / nar->size()) * 100.0),
         duration);
 
-    narInfo->url = "nar/" + narInfo->fileHash.to_string(Base32, false) + ".nar"
+    narInfo->url = "nar/" + narInfo->fileHash.to_string(Base::Base32, false) + ".nar"
         + (compression == "xz" ? ".xz" :
            compression == "bzip2" ? ".bz2" :
            compression == "br" ? ".br" :
@@ -206,7 +206,7 @@ void BinaryCacheStore::addToStore(const ValidPathInfo & info, const ref<std::str
                 // to a GC'ed file, so overwriting might be useful...
                 if (fileExists(key)) return;
 
-                printMsg(lvlTalkative, "creating debuginfo link from '%s' to '%s'", key, target);
+                printMsg(Verbosity::Talkative, "creating debuginfo link from '%s' to '%s'", key, target);
 
                 upsertFile(key, json.dump(), "application/json");
             };
@@ -299,7 +299,7 @@ void BinaryCacheStore::queryPathInfoUncached(const StorePath & storePath,
 {
     auto uri = getUri();
     auto storePathS = printStorePath(storePath);
-    auto act = std::make_shared<Activity>(*logger, lvlTalkative, actQueryPathInfo,
+    auto act = std::make_shared<Activity>(*logger, Verbosity::Talkative, ActivityType::QueryPathInfo,
         fmt("querying info about '%s' on '%s'", storePathS, uri), Logger::Fields{storePathS, uri});
     PushActivity pact(act->id);
 
diff --git a/src/libstore/build.cc b/src/libstore/build.cc
index 0e3a23a4d..0259cfd0b 100644
--- a/src/libstore/build.cc
+++ b/src/libstore/build.cc
@@ -107,7 +107,13 @@ typedef std::map<StorePath, WeakGoalPtr> WeakGoalMap;
 class Goal : public std::enable_shared_from_this<Goal>
 {
 public:
-    typedef enum {ecBusy, ecSuccess, ecFailed, ecNoSubstituters, ecIncompleteClosure} ExitCode;
+    enum struct ExitCode {
+        Busy,
+        Success,
+        Failed,
+        NoSubstituters,
+        IncompleteClosure,
+    };
 
 protected:
 
@@ -141,7 +147,7 @@ protected:
     Goal(Worker & worker) : worker(worker)
     {
         nrFailed = nrNoSubstituters = nrIncompleteClosure = 0;
-        exitCode = ecBusy;
+        exitCode = ExitCode::Busy;
     }
 
     virtual ~Goal()
@@ -361,8 +367,8 @@ public:
     {
         actDerivations.progress(doneBuilds, expectedBuilds + doneBuilds, runningBuilds, failedBuilds);
         actSubstitutions.progress(doneSubstitutions, expectedSubstitutions + doneSubstitutions, runningSubstitutions, failedSubstitutions);
-        act.setExpected(actDownload, expectedDownloadSize + doneDownloadSize);
-        act.setExpected(actCopyPath, expectedNarSize + doneNarSize);
+        act.setExpected(ActivityType::Download, expectedDownloadSize + doneDownloadSize);
+        act.setExpected(ActivityType::CopyPath, expectedNarSize + doneNarSize);
     }
 };
 
@@ -395,13 +401,13 @@ void Goal::waiteeDone(GoalPtr waitee, ExitCode result)
     trace(format("waitee '%1%' done; %2% left") %
         waitee->name % waitees.size());
 
-    if (result == ecFailed || result == ecNoSubstituters || result == ecIncompleteClosure) ++nrFailed;
+    if (result == ExitCode::Failed || result == ExitCode::NoSubstituters || result == ExitCode::IncompleteClosure) ++nrFailed;
 
-    if (result == ecNoSubstituters) ++nrNoSubstituters;
+    if (result == ExitCode::NoSubstituters) ++nrNoSubstituters;
 
-    if (result == ecIncompleteClosure) ++nrIncompleteClosure;
+    if (result == ExitCode::IncompleteClosure) ++nrIncompleteClosure;
 
-    if (waitees.empty() || (result == ecFailed && !settings.keepGoing)) {
+    if (waitees.empty() || (result == ExitCode::Failed && !settings.keepGoing)) {
 
         /* If we failed and keepGoing is not set, we remove all
            remaining waitees. */
@@ -421,8 +427,8 @@ void Goal::waiteeDone(GoalPtr waitee, ExitCode result)
 void Goal::amDone(ExitCode result)
 {
     trace("done");
-    assert(exitCode == ecBusy);
-    assert(result == ecSuccess || result == ecFailed || result == ecNoSubstituters || result == ecIncompleteClosure);
+    assert(exitCode == ExitCode::Busy);
+    assert(result == ExitCode::Success || result == ExitCode::Failed || result == ExitCode::NoSubstituters || result == ExitCode::IncompleteClosure);
     exitCode = result;
     for (auto & i : waiters) {
         GoalPtr goal = i.lock();
@@ -668,7 +674,7 @@ HookInstance::HookInstance()
 
         Strings args = {
             std::string(baseNameOf(settings.buildHook.get())),
-            std::to_string(verbosity),
+            std::to_string((uint64_t)verbosity),
         };
 
         execv(settings.buildHook.get().c_str(), stringsToCharPtrs(args).data());
@@ -1445,7 +1451,7 @@ void DerivationGoal::tryToBuild()
             "building '%s'", worker.store.printStorePath(drvPath), curRound, nrRounds);
         fmt("building '%s'", worker.store.printStorePath(drvPath));
         if (hook) msg += fmt(" on '%s'", machineName);
-        act = std::make_unique<Activity>(*logger, lvlInfo, actBuild, msg,
+        act = std::make_unique<Activity>(*logger, Verbosity::Info, ActivityType::Build, msg,
             Logger::Fields{worker.store.printStorePath(drvPath), hook ? machineName : "", curRound, nrRounds});
         mcRunningBuilds = std::make_unique<MaintainCount<uint64_t>>(worker.runningBuilds);
         worker.updateProgress();
@@ -1625,7 +1631,7 @@ void DerivationGoal::buildDone()
         registerOutputs();
 
         if (settings.postBuildHook != "") {
-            Activity act(*logger, lvlInfo, actPostBuildHook,
+            Activity act(*logger, Verbosity::Info, ActivityType::PostBuildHook,
                 fmt("running post-build-hook '%s'", settings.postBuildHook),
                 Logger::Fields{worker.store.printStorePath(drvPath)});
             PushActivity pact(act.id);
@@ -1660,7 +1666,7 @@ void DerivationGoal::buildDone()
                     if (settings.verboseBuild) {
                         printError("post-build-hook: " + currentLine);
                     } else {
-                        act.result(resPostBuildLogLine, currentLine);
+                        act.result(ResultType::PostBuildLogLine, currentLine);
                     }
                     currentLine.clear();
                 }
@@ -2078,7 +2084,7 @@ void DerivationGoal::startBuilder()
         /* Clean up the chroot directory automatically. */
         autoDelChroot = std::make_shared<AutoDelete>(chrootRootDir);
 
-        printMsg(lvlChatty, format("setting up chroot environment in '%1%'") % chrootRootDir);
+        printMsg(Verbosity::Chatty, format("setting up chroot environment in '%1%'") % chrootRootDir);
 
         if (mkdir(chrootRootDir.c_str(), 0750) == -1)
             throw SysError(format("cannot create '%1%'") % chrootRootDir);
@@ -2187,7 +2193,7 @@ void DerivationGoal::startBuilder()
     }
 
     if (useChroot && settings.preBuildHook != "" && dynamic_cast<Derivation *>(drv.get())) {
-        printMsg(lvlChatty, format("executing pre-build hook '%1%'")
+        printMsg(Verbosity::Chatty, format("executing pre-build hook '%1%'")
             % settings.preBuildHook);
         auto args = useChroot ? Strings({worker.store.printStorePath(drvPath), chrootRootDir}) :
             Strings({ worker.store.printStorePath(drvPath) });
@@ -2229,7 +2235,7 @@ void DerivationGoal::startBuilder()
         startDaemon();
 
     /* Run the builder. */
-    printMsg(lvlChatty, format("executing builder '%1%'") % drv->builder);
+    printMsg(Verbosity::Chatty, format("executing builder '%1%'") % drv->builder);
 
     /* Create the log file. */
     Path logFile = openLogFile();
@@ -2462,8 +2468,8 @@ void DerivationGoal::initTmpDir() {
             if (passAsFile.find(i.first) == passAsFile.end()) {
                 env[i.first] = i.second;
             } else {
-                auto hash = hashString(htSHA256, i.first);
-                string fn = ".attr-" + hash.to_string(Base32, false);
+                auto hash = hashString(HashType::SHA256, i.first);
+                string fn = ".attr-" + hash.to_string(Base::Base32, false);
                 Path p = tmpDir + "/" + fn;
                 writeFile(p, i.second);
                 chownToBuilder(p);
@@ -2712,7 +2718,7 @@ struct RestrictedStore : public LocalFSStore
     { throw Error("queryPathFromHashPart"); }
 
     StorePath addToStore(const string & name, const Path & srcPath,
-        bool recursive = true, HashType hashAlgo = htSHA256,
+        bool recursive = true, HashType hashAlgo = HashType::SHA256,
         PathFilter & filter = defaultPathFilter, RepairFlag repair = NoRepair) override
     { throw Error("addToStore"); }
 
@@ -2725,7 +2731,7 @@ struct RestrictedStore : public LocalFSStore
     }
 
     StorePath addToStoreFromDump(const string & dump, const string & name,
-        bool recursive = true, HashType hashAlgo = htSHA256, RepairFlag repair = NoRepair) override
+        bool recursive = true, HashType hashAlgo = HashType::SHA256, RepairFlag repair = NoRepair) override
     {
         auto path = next->addToStoreFromDump(dump, name, recursive, hashAlgo, repair);
         goal.addDependency(path);
@@ -3670,7 +3676,7 @@ void DerivationGoal::registerOutputs()
                 worker.hashMismatch = true;
                 delayedException = std::make_exception_ptr(
                     BuildError("hash mismatch in fixed-output derivation '%s':\n  wanted: %s\n  got:    %s",
-                        worker.store.printStorePath(dest), h.to_string(SRI), h2.to_string(SRI)));
+                        worker.store.printStorePath(dest), h.to_string(Base::SRI), h2.to_string(Base::SRI)));
 
                 Path actualDest = worker.store.Store::toRealPath(dest);
 
@@ -4114,7 +4120,7 @@ void DerivationGoal::flushLine()
             if (logTail.size() > settings.logLines) logTail.pop_front();
         }
 
-        act->result(resBuildLogLine, currentLogLine);
+        act->result(ResultType::BuildLogLine, currentLogLine);
     }
 
     currentLogLine = "";
@@ -4141,7 +4147,7 @@ void DerivationGoal::addHashRewrite(const StorePath & path)
     auto h1 = std::string(((std::string_view) path.to_string()).substr(0, 32));
     auto p = worker.store.makeStorePath(
         "rewrite:" + std::string(drvPath.to_string()) + ":" + std::string(path.to_string()),
-        Hash(htSHA256), path.name());
+        Hash(HashType::SHA256), path.name());
     auto h2 = std::string(((std::string_view) p.to_string()).substr(0, 32));
     deletePath(worker.store.printStorePath(p));
     inputRewrites[h1] = h2;
@@ -4154,7 +4160,7 @@ void DerivationGoal::done(BuildResult::Status status, const string & msg)
 {
     result.status = status;
     result.errorMsg = msg;
-    amDone(result.success() ? ecSuccess : ecFailed);
+    amDone(result.success() ? ExitCode::Success : ExitCode::Failed);
     if (result.status == BuildResult::TimedOut)
         worker.timedOut = true;
     if (result.status == BuildResult::PermanentFailure)
@@ -4295,7 +4301,7 @@ void SubstitutionGoal::init()
 
     /* If the path already exists we're done. */
     if (!repair && worker.store.isValidPath(storePath)) {
-        amDone(ecSuccess);
+        amDone(ExitCode::Success);
         return;
     }
 
@@ -4320,7 +4326,7 @@ void SubstitutionGoal::tryNext()
         /* Hack: don't indicate failure if there were no substituters.
            In that case the calling derivation should just do a
            build. */
-        amDone(substituterFailed ? ecFailed : ecNoSubstituters);
+        amDone(substituterFailed ? ExitCode::Failed : ExitCode::NoSubstituters);
 
         if (substituterFailed) {
             worker.failedSubstitutions++;
@@ -4403,7 +4409,7 @@ void SubstitutionGoal::referencesValid()
 
     if (nrFailed > 0) {
         debug("some references of path '%s' could not be realised", worker.store.printStorePath(storePath));
-        amDone(nrNoSubstituters > 0 || nrIncompleteClosure > 0 ? ecIncompleteClosure : ecFailed);
+        amDone(nrNoSubstituters > 0 || nrIncompleteClosure > 0 ? ExitCode::IncompleteClosure : ExitCode::Failed);
         return;
     }
 
@@ -4441,7 +4447,7 @@ void SubstitutionGoal::tryToRun()
             /* Wake up the worker loop when we're done. */
             Finally updateStats([this]() { outPipe.writeSide = -1; });
 
-            Activity act(*logger, actSubstitute, Logger::Fields{worker.store.printStorePath(storePath), sub->getUri()});
+            Activity act(*logger, ActivityType::Substitute, Logger::Fields{worker.store.printStorePath(storePath), sub->getUri()});
             PushActivity pact(act.id);
 
             copyStorePath(ref<Store>(sub), ref<Store>(worker.store.shared_from_this()),
@@ -4490,7 +4496,7 @@ void SubstitutionGoal::finished()
 
     worker.markContentsGood(storePath.clone());
 
-    printMsg(lvlChatty, "substitution of path '%s' succeeded", worker.store.printStorePath(storePath));
+    printMsg(Verbosity::Chatty, "substitution of path '%s' succeeded", worker.store.printStorePath(storePath));
 
     maintainRunningSubstitutions.reset();
 
@@ -4508,7 +4514,7 @@ void SubstitutionGoal::finished()
 
     worker.updateProgress();
 
-    amDone(ecSuccess);
+    amDone(ExitCode::Success);
 }
 
 
@@ -4527,9 +4533,9 @@ void SubstitutionGoal::handleEOF(int fd)
 
 
 Worker::Worker(LocalStore & store)
-    : act(*logger, actRealise)
-    , actDerivations(*logger, actBuilds)
-    , actSubstitutions(*logger, actCopyPaths)
+    : act(*logger, ActivityType::Realise)
+    , actDerivations(*logger, ActivityType::Builds)
+    , actSubstitutions(*logger, ActivityType::CopyPaths)
     , store(store)
 {
     /* Debugging: prevent recursive workers. */
@@ -4613,7 +4619,7 @@ void Worker::removeGoal(GoalPtr goal)
         topGoals.erase(goal);
         /* If a top-level goal failed, then kill all other goals
            (unless keepGoing was set). */
-        if (goal->getExitCode() == Goal::ecFailed && !settings.keepGoing)
+        if (goal->getExitCode() == Goal::ExitCode::Failed && !settings.keepGoing)
             topGoals.clear();
     }
 
@@ -4757,7 +4763,7 @@ void Worker::run(const Goals & _topGoals)
 
 void Worker::waitForInput()
 {
-    printMsg(lvlVomit, "waiting for children");
+    printMsg(Verbosity::Vomit, "waiting for children");
 
     /* Process output from the file descriptors attached to the
        children, namely log output and output path creation commands.
@@ -4852,7 +4858,7 @@ void Worker::waitForInput()
                     if (errno != EINTR)
                         throw SysError("%s: read failed", goal->getName());
                 } else {
-                    printMsg(lvlVomit, format("%1%: read %2% bytes")
+                    printMsg(Verbosity::Vomit, format("%1%: read %2% bytes")
                         % goal->getName() % rd);
                     string data((char *) buffer.data(), rd);
                     j->lastOutput = after;
@@ -4861,7 +4867,7 @@ void Worker::waitForInput()
             }
         }
 
-        if (goal->getExitCode() == Goal::ecBusy &&
+        if (goal->getExitCode() == Goal::ExitCode::Busy &&
             0 != settings.maxSilentTime &&
             j->respectTimeouts &&
             after - j->lastOutput >= std::chrono::seconds(settings.maxSilentTime))
@@ -4872,7 +4878,7 @@ void Worker::waitForInput()
             goal->timedOut();
         }
 
-        else if (goal->getExitCode() == Goal::ecBusy &&
+        else if (goal->getExitCode() == Goal::ExitCode::Busy &&
             0 != settings.buildTimeout &&
             j->respectTimeouts &&
             after - j->timeStarted >= std::chrono::seconds(settings.buildTimeout))
@@ -4934,7 +4940,7 @@ bool Worker::pathContentsGood(const StorePath & path)
         res = false;
     else {
         HashResult current = hashPath(info->narHash.type, store.printStorePath(path));
-        Hash nullHash(htSHA256);
+        Hash nullHash(HashType::SHA256);
         res = info->narHash == nullHash || info->narHash == current.first;
     }
     pathContentsGoodCache.insert_or_assign(path.clone(), res);
@@ -4983,7 +4989,7 @@ void LocalStore::buildPaths(const std::vector<StorePathWithOutputs> & drvPaths,
 
     StorePathSet failed;
     for (auto & i : goals) {
-        if (i->getExitCode() != Goal::ecSuccess) {
+        if (i->getExitCode() != Goal::ExitCode::Success) {
             DerivationGoal * i2 = dynamic_cast<DerivationGoal *>(i.get());
             if (i2) failed.insert(i2->getDrvPath());
             else failed.insert(dynamic_cast<SubstitutionGoal *>(i.get())->getStorePath());
@@ -5028,7 +5034,7 @@ void LocalStore::ensurePath(const StorePath & path)
 
     worker.run(goals);
 
-    if (goal->getExitCode() != Goal::ecSuccess)
+    if (goal->getExitCode() != Goal::ExitCode::Success)
         throw Error(worker.exitStatus(), "path '%s' does not exist and cannot be created", printStorePath(path));
 }
 
@@ -5041,7 +5047,7 @@ void LocalStore::repairPath(const StorePath & path)
 
     worker.run(goals);
 
-    if (goal->getExitCode() != Goal::ecSuccess) {
+    if (goal->getExitCode() != Goal::ExitCode::Success) {
         /* Since substituting the path didn't work, if we have a valid
            deriver, then rebuild the deriver. */
         auto info = queryPathInfo(path);
diff --git a/src/libstore/builtins/fetchurl.cc b/src/libstore/builtins/fetchurl.cc
index f6ae5d2e6..809689d44 100644
--- a/src/libstore/builtins/fetchurl.cc
+++ b/src/libstore/builtins/fetchurl.cc
@@ -65,7 +65,7 @@ void builtinFetchurl(const BasicDerivation & drv, const std::string & netrcData)
                 if (!hasSuffix(hashedMirror, "/")) hashedMirror += '/';
                 auto ht = parseHashType(getAttr("outputHashAlgo"));
                 auto h = Hash(getAttr("outputHash"), ht);
-                fetch(hashedMirror + printHashType(h.type) + "/" + h.to_string(Base16, false));
+                fetch(hashedMirror + printHashType(h.type) + "/" + h.to_string(Base::Base16, false));
                 return;
             } catch (Error & e) {
                 debug(e.what());
diff --git a/src/libstore/daemon.cc b/src/libstore/daemon.cc
index 8e9f9d71b..f854d1ebd 100644
--- a/src/libstore/daemon.cc
+++ b/src/libstore/daemon.cc
@@ -114,7 +114,13 @@ struct TunnelLogger : public Logger
         }
 
         StringSink buf;
-        buf << STDERR_START_ACTIVITY << act << lvl << type << s << fields << parent;
+        buf << STDERR_START_ACTIVITY 
+            << act
+            << (uint64_t) lvl
+            << (uint64_t) type
+            << s
+            << fields
+            << parent;
         enqueueMsg(*buf.s);
     }
 
@@ -130,7 +136,10 @@ struct TunnelLogger : public Logger
     {
         if (GET_PROTOCOL_MINOR(clientVersion) < 20) return;
         StringSink buf;
-        buf << STDERR_RESULT << act << type << fields;
+        buf << STDERR_RESULT
+            << act
+            << (uint64_t) type
+            << fields;
         enqueueMsg(*buf.s);
     }
 };
@@ -302,7 +311,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         logger->startWork();
         auto hash = store->queryPathInfo(path)->narHash;
         logger->stopWork();
-        to << hash.to_string(Base16, false);
+        to << hash.to_string(Base::Base16, false);
         break;
     }
 
@@ -542,7 +551,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         clientSettings.maxBuildJobs = readInt(from);
         clientSettings.maxSilentTime = readInt(from);
         readInt(from); // obsolete useBuildHook
-        clientSettings.verboseBuild = lvlError == (Verbosity) readInt(from);
+        clientSettings.verboseBuild = Verbosity::Error == (Verbosity) readInt(from);
         readInt(from); // obsolete logType
         readInt(from); // obsolete printBuildTrace
         clientSettings.buildCores = readInt(from);
@@ -627,7 +636,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
             if (GET_PROTOCOL_MINOR(clientVersion) >= 17)
                 to << 1;
             to << (info->deriver ? store->printStorePath(*info->deriver) : "")
-               << info->narHash.to_string(Base16, false);
+               << info->narHash.to_string(Base::Base16, false);
             writeStorePaths(*store, to, info->references);
             to << info->registrationTime << info->narSize;
             if (GET_PROTOCOL_MINOR(clientVersion) >= 16) {
@@ -687,7 +696,7 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
         auto deriver = readString(from);
         if (deriver != "")
             info.deriver = store->parseStorePath(deriver);
-        info.narHash = Hash(readString(from), htSHA256);
+        info.narHash = Hash(readString(from), HashType::SHA256);
         info.references = readStorePaths<StorePathSet>(*store, from);
         from >> info.registrationTime >> info.narSize >> info.ultimate;
         info.sigs = readStrings<StringSet>(from);
@@ -770,7 +779,7 @@ void processConnection(
 
     Finally finally([&]() {
         _isInterrupted = false;
-        prevLogger->log(lvlDebug, fmt("%d operations", opCount));
+        prevLogger->log(Verbosity::Debug, fmt("%d operations", opCount));
     });
 
     if (GET_PROTOCOL_MINOR(clientVersion) >= 14 && readInt(from)) {
diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc
index 973ddc86a..38b4122dd 100644
--- a/src/libstore/derivations.cc
+++ b/src/libstore/derivations.cc
@@ -20,7 +20,7 @@ void DerivationOutput::parseHashInfo(bool & recursive, Hash & hash) const
     }
 
     HashType hashType = parseHashType(algo);
-    if (hashType == htUnknown)
+    if (hashType == HashType::Unknown)
         throw Error("unknown hash algorithm '%s'", algo);
 
     hash = Hash(this->hash, hashType);
@@ -364,7 +364,7 @@ Hash hashDerivationModulo(Store & store, const Derivation & drv, bool maskOutput
     /* Return a fixed hash for fixed-output derivations. */
     if (drv.isFixedOutput()) {
         DerivationOutputs::const_iterator i = drv.outputs.begin();
-        return hashString(htSHA256, "fixed:out:"
+        return hashString(HashType::SHA256, "fixed:out:"
             + i->second.hashAlgo + ":"
             + i->second.hash + ":"
             + store.printStorePath(i->second.path));
@@ -380,10 +380,10 @@ Hash hashDerivationModulo(Store & store, const Derivation & drv, bool maskOutput
             h = drvHashes.insert_or_assign(i.first.clone(), hashDerivationModulo(store,
                 readDerivation(store, store.toRealPath(store.printStorePath(i.first))), false)).first;
         }
-        inputs2.insert_or_assign(h->second.to_string(Base16, false), i.second);
+        inputs2.insert_or_assign(h->second.to_string(Base::Base16, false), i.second);
     }
 
-    return hashString(htSHA256, drv.unparse(store, maskOutputs, &inputs2));
+    return hashString(HashType::SHA256, drv.unparse(store, maskOutputs, &inputs2));
 }
 
 
@@ -453,7 +453,7 @@ void writeDerivation(Sink & out, const Store & store, const BasicDerivation & dr
 std::string hashPlaceholder(const std::string & outputName)
 {
     // FIXME: memoize?
-    return "/" + hashString(htSHA256, "nix-output:" + outputName).to_string(Base32, false);
+    return "/" + hashString(HashType::SHA256, "nix-output:" + outputName).to_string(Base::Base32, false);
 }
 
 
diff --git a/src/libstore/download.cc b/src/libstore/download.cc
index 149c84765..99ce291f4 100644
--- a/src/libstore/download.cc
+++ b/src/libstore/download.cc
@@ -85,7 +85,7 @@ struct CurlDownloader : public Downloader
             Callback<DownloadResult> && callback)
             : downloader(downloader)
             , request(request)
-            , act(*logger, lvlTalkative, actDownload,
+            , act(*logger, Verbosity::Talkative, ActivityType::Download,
                 fmt(request.data ? "uploading '%s'" : "downloading '%s'", request.uri),
                 {request.uri}, request.parentAct)
             , callback(std::move(callback))
@@ -164,7 +164,7 @@ struct CurlDownloader : public Downloader
         {
             size_t realSize = size * nmemb;
             std::string line((char *) contents, realSize);
-            printMsg(lvlVomit, format("got header for '%s': %s") % request.uri % trim(line));
+            printMsg(Verbosity::Vomit, format("got header for '%s': %s") % request.uri % trim(line));
             if (line.compare(0, 5, "HTTP/") == 0) { // new response starts
                 result.etag = "";
                 auto ss = tokenizeString<vector<string>>(line, " ");
@@ -247,7 +247,7 @@ struct CurlDownloader : public Downloader
 
             curl_easy_reset(req);
 
-            if (verbosity >= lvlVomit) {
+            if (verbosity >= Verbosity::Vomit) {
                 curl_easy_setopt(req, CURLOPT_VERBOSE, 1);
                 curl_easy_setopt(req, CURLOPT_DEBUGFUNCTION, DownloadItem::debugCallback);
             }
@@ -826,7 +826,7 @@ CachedDownloadResult Downloader::downloadCached(
     Path cacheDir = getCacheDir() + "/nix/tarballs";
     createDirs(cacheDir);
 
-    string urlHash = hashString(htSHA256, name + std::string("\0"s) + url).to_string(Base32, false);
+    string urlHash = hashString(HashType::SHA256, name + std::string("\0"s) + url).to_string(Base::Base32, false);
 
     Path dataFile = cacheDir + "/" + urlHash + ".info";
     Path fileLink = cacheDir + "/" + urlHash + "-file";
@@ -874,9 +874,9 @@ CachedDownloadResult Downloader::downloadCached(
             if (!res.cached) {
                 StringSink sink;
                 dumpString(*res.data, sink);
-                Hash hash = hashString(request.expectedHash ? request.expectedHash.type : htSHA256, *res.data);
+                Hash hash = hashString(request.expectedHash ? request.expectedHash.type : HashType::SHA256, *res.data);
                 ValidPathInfo info(store->makeFixedOutputPath(false, hash, name));
-                info.narHash = hashString(htSHA256, *sink.s);
+                info.narHash = hashString(HashType::SHA256, *sink.s);
                 info.narSize = sink.s->size();
                 info.ca = makeFixedOutputCA(false, hash);
                 store->addToStore(info, sink.s, NoRepair, NoCheckSigs);
@@ -914,7 +914,7 @@ CachedDownloadResult Downloader::downloadCached(
             if (members.size() != 1)
                 throw nix::Error("tarball '%s' contains an unexpected number of top-level files", url);
             auto topDir = tmpDir + "/" + members.begin()->name;
-            unpackedStorePath = store->addToStore(name, topDir, true, htSHA256, defaultPathFilter, NoRepair);
+            unpackedStorePath = store->addToStore(name, topDir, true, HashType::SHA256, defaultPathFilter, NoRepair);
         }
         replaceSymlink(store->printStorePath(*unpackedStorePath), unpackedLink);
         storePath = std::move(*unpackedStorePath);
diff --git a/src/libstore/export-import.cc b/src/libstore/export-import.cc
index 4692d1a7b..8a5e9d08e 100644
--- a/src/libstore/export-import.cc
+++ b/src/libstore/export-import.cc
@@ -10,7 +10,7 @@ struct HashAndWriteSink : Sink
 {
     Sink & writeSink;
     HashSink hashSink;
-    HashAndWriteSink(Sink & writeSink) : writeSink(writeSink), hashSink(htSHA256)
+    HashAndWriteSink(Sink & writeSink) : writeSink(writeSink), hashSink(HashType::SHA256)
     {
     }
     virtual void operator () (const unsigned char * data, size_t len)
@@ -33,7 +33,7 @@ void Store::exportPaths(const StorePathSet & paths, Sink & sink)
     //logger->incExpected(doneLabel, sorted.size());
 
     for (auto & path : sorted) {
-        //Activity act(*logger, lvlInfo, format("exporting path '%s'") % path);
+        //Activity act(*logger, Verbosity::Info, format("exporting path '%s'") % path);
         sink << 1;
         exportPath(path, sink);
         //logger->incProgress(doneLabel);
@@ -85,7 +85,7 @@ StorePaths Store::importPaths(Source & source, std::shared_ptr<FSAccessor> acces
 
         ValidPathInfo info(parseStorePath(readString(source)));
 
-        //Activity act(*logger, lvlInfo, format("importing path '%s'") % info.path);
+        //Activity act(*logger, Verbosity::Info, format("importing path '%s'") % info.path);
 
         info.references = readStorePaths<StorePathSet>(*this, source);
 
@@ -93,7 +93,7 @@ StorePaths Store::importPaths(Source & source, std::shared_ptr<FSAccessor> acces
         if (deriver != "")
             info.deriver = parseStorePath(deriver);
 
-        info.narHash = hashString(htSHA256, *tee.source.data);
+        info.narHash = hashString(HashType::SHA256, *tee.source.data);
         info.narSize = tee.source.data->size();
 
         // Ignore optional legacy signature.
diff --git a/src/libstore/gc.cc b/src/libstore/gc.cc
index 0c3d89611..d201958f5 100644
--- a/src/libstore/gc.cc
+++ b/src/libstore/gc.cc
@@ -78,7 +78,7 @@ void LocalStore::syncWithGC()
 
 void LocalStore::addIndirectRoot(const Path & path)
 {
-    string hash = hashString(htSHA1, path).to_string(Base32, false);
+    string hash = hashString(HashType::SHA1, path).to_string(Base::Base32, false);
     Path realRoot = canonPath((format("%1%/%2%/auto/%3%")
         % stateDir % gcRootsDir % hash).str());
     makeSymlink(realRoot, path);
@@ -632,7 +632,7 @@ void LocalStore::tryToDelete(GCState & state, const Path & path)
     auto realPath = realStoreDir + "/" + std::string(baseNameOf(path));
     if (realPath == linksDir || realPath == trashDir) return;
 
-    //Activity act(*logger, lvlDebug, format("considering whether to delete '%1%'") % path);
+    //Activity act(*logger, Verbosity::Debug, format("considering whether to delete '%1%'") % path);
 
     auto storePath = maybeParseStorePath(path);
 
@@ -697,7 +697,7 @@ void LocalStore::removeUnusedLinks(const GCState & state)
             continue;
         }
 
-        printMsg(lvlTalkative, format("deleting unused link '%1%'") % path);
+        printMsg(Verbosity::Talkative, format("deleting unused link '%1%'") % path);
 
         if (unlink(path.c_str()) == -1)
             throw SysError(format("deleting '%1%'") % path);
diff --git a/src/libstore/legacy-ssh-store.cc b/src/libstore/legacy-ssh-store.cc
index 458266be0..f123efe01 100644
--- a/src/libstore/legacy-ssh-store.cc
+++ b/src/libstore/legacy-ssh-store.cc
@@ -139,7 +139,7 @@ struct LegacySSHStore : public Store
                 << cmdAddToStoreNar
                 << printStorePath(info.path)
                 << (info.deriver ? printStorePath(*info.deriver) : "")
-                << info.narHash.to_string(Base16, false);
+                << info.narHash.to_string(Base::Base16, false);
             writeStorePaths(*this, conn->to, info.references);
             conn->to
                 << info.registrationTime
diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc
index ae7513ad8..f293ecb4a 100644
--- a/src/libstore/local-store.cc
+++ b/src/libstore/local-store.cc
@@ -580,7 +580,7 @@ uint64_t LocalStore::addValidPath(State & state,
 
     state.stmtRegisterValidPath.use()
         (printStorePath(info.path))
-        (info.narHash.to_string(Base16))
+        (info.narHash.to_string(Base::Base16))
         (info.registrationTime == 0 ? time(0) : info.registrationTime)
         (info.deriver ? printStorePath(*info.deriver) : "", (bool) info.deriver)
         (info.narSize, info.narSize != 0)
@@ -680,7 +680,7 @@ void LocalStore::updatePathInfo(State & state, const ValidPathInfo & info)
 {
     state.stmtUpdatePathInfo.use()
         (info.narSize, info.narSize != 0)
-        (info.narHash.to_string(Base16))
+        (info.narHash.to_string(Base::Base16))
         (info.ultimate ? 1 : 0, info.ultimate)
         (concatStringsSep(" ", info.sigs), !info.sigs.empty())
         (info.ca, !info.ca.empty())
@@ -908,7 +908,7 @@ void LocalStore::registerValidPaths(const ValidPathInfos & infos)
         StorePathSet paths;
 
         for (auto & i : infos) {
-            assert(i.narHash.type == htSHA256);
+            assert(i.narHash.type == HashType::SHA256);
             if (isValidPath_(*state, i.path))
                 updatePathInfo(*state, i);
             else
@@ -1006,9 +1006,9 @@ void LocalStore::addToStore(const ValidPathInfo & info, Source & source,
                of the NAR. */
             std::unique_ptr<AbstractHashSink> hashSink;
             if (info.ca == "" || !info.references.count(info.path))
-                hashSink = std::make_unique<HashSink>(htSHA256);
+                hashSink = std::make_unique<HashSink>(HashType::SHA256);
             else
-                hashSink = std::make_unique<HashModuloSink>(htSHA256, storePathToHash(printStorePath(info.path)));
+                hashSink = std::make_unique<HashModuloSink>(HashType::SHA256, storePathToHash(printStorePath(info.path)));
 
             LambdaSource wrapperSource([&](unsigned char * data, size_t len) -> size_t {
                 size_t n = source.read(data, len);
@@ -1081,10 +1081,10 @@ StorePath LocalStore::addToStoreFromDump(const string & dump, const string & nam
                sha256); otherwise, compute it here. */
             HashResult hash;
             if (recursive) {
-                hash.first = hashAlgo == htSHA256 ? h : hashString(htSHA256, dump);
+                hash.first = hashAlgo == HashType::SHA256 ? h : hashString(HashType::SHA256, dump);
                 hash.second = dump.size();
             } else
-                hash = hashPath(htSHA256, realPath);
+                hash = hashPath(HashType::SHA256, realPath);
 
             optimisePath(realPath); // FIXME: combine with hashPath()
 
@@ -1123,7 +1123,7 @@ StorePath LocalStore::addToStore(const string & name, const Path & _srcPath,
 StorePath LocalStore::addTextToStore(const string & name, const string & s,
     const StorePathSet & references, RepairFlag repair)
 {
-    auto hash = hashString(htSHA256, s);
+    auto hash = hashString(HashType::SHA256, s);
     auto dstPath = makeTextPath(name, hash, references);
 
     addTempRoot(dstPath);
@@ -1147,7 +1147,7 @@ StorePath LocalStore::addTextToStore(const string & name, const string & s,
 
             StringSink sink;
             dumpString(s, sink);
-            auto narHash = hashString(htSHA256, *sink.s);
+            auto narHash = hashString(HashType::SHA256, *sink.s);
 
             optimisePath(realPath);
 
@@ -1233,9 +1233,9 @@ bool LocalStore::verifyStore(bool checkContents, RepairFlag repair)
         printInfo("checking link hashes...");
 
         for (auto & link : readDirectory(linksDir)) {
-            printMsg(lvlTalkative, "checking contents of '%s'", link.name);
+            printMsg(Verbosity::Talkative, "checking contents of '%s'", link.name);
             Path linkPath = linksDir + "/" + link.name;
-            string hash = hashPath(htSHA256, linkPath).first.to_string(Base32, false);
+            string hash = hashPath(HashType::SHA256, linkPath).first.to_string(Base::Base32, false);
             if (hash != link.name) {
                 printError(
                     "link '%s' was modified! expected hash '%s', got '%s'",
@@ -1253,14 +1253,14 @@ bool LocalStore::verifyStore(bool checkContents, RepairFlag repair)
 
         printInfo("checking store hashes...");
 
-        Hash nullHash(htSHA256);
+        Hash nullHash(HashType::SHA256);
 
         for (auto & i : validPaths) {
             try {
                 auto info = std::const_pointer_cast<ValidPathInfo>(std::shared_ptr<const ValidPathInfo>(queryPathInfo(i)));
 
                 /* Check the content hash (optionally - slow). */
-                printMsg(lvlTalkative, "checking contents of '%s'", printStorePath(i));
+                printMsg(Verbosity::Talkative, "checking contents of '%s'", printStorePath(i));
 
                 std::unique_ptr<AbstractHashSink> hashSink;
                 if (info->ca == "" || !info->references.count(info->path))
diff --git a/src/libstore/local-store.hh b/src/libstore/local-store.hh
index 16aeab0ad..76bacd326 100644
--- a/src/libstore/local-store.hh
+++ b/src/libstore/local-store.hh
@@ -157,7 +157,7 @@ public:
        true) or simply the contents of a regular file (if recursive ==
        false). */
     StorePath addToStoreFromDump(const string & dump, const string & name,
-        bool recursive = true, HashType hashAlgo = htSHA256, RepairFlag repair = NoRepair) override;
+        bool recursive = true, HashType hashAlgo = HashType::SHA256, RepairFlag repair = NoRepair) override;
 
     StorePath addTextToStore(const string & name, const string & s,
         const StorePathSet & references, RepairFlag repair) override;
diff --git a/src/libstore/misc.cc b/src/libstore/misc.cc
index 9c47fe524..fb538a1c5 100644
--- a/src/libstore/misc.cc
+++ b/src/libstore/misc.cc
@@ -112,7 +112,7 @@ void Store::queryMissing(const std::vector<StorePathWithOutputs> & targets,
     StorePathSet & willBuild_, StorePathSet & willSubstitute_, StorePathSet & unknown_,
     unsigned long long & downloadSize_, unsigned long long & narSize_)
 {
-    Activity act(*logger, lvlDebug, actUnknown, "querying info about missing paths");
+    Activity act(*logger, Verbosity::Debug, ActivityType::Unknown, "querying info about missing paths");
 
     downloadSize_ = narSize_ = 0;
 
diff --git a/src/libstore/nar-info.cc b/src/libstore/nar-info.cc
index 1375094b5..a35886302 100644
--- a/src/libstore/nar-info.cc
+++ b/src/libstore/nar-info.cc
@@ -86,11 +86,11 @@ std::string NarInfo::to_string(const Store & store) const
     res += "URL: " + url + "\n";
     assert(compression != "");
     res += "Compression: " + compression + "\n";
-    assert(fileHash.type == htSHA256);
-    res += "FileHash: " + fileHash.to_string(Base32) + "\n";
+    assert(fileHash.type == HashType::SHA256);
+    res += "FileHash: " + fileHash.to_string(Base::Base32) + "\n";
     res += "FileSize: " + std::to_string(fileSize) + "\n";
-    assert(narHash.type == htSHA256);
-    res += "NarHash: " + narHash.to_string(Base32) + "\n";
+    assert(narHash.type == HashType::SHA256);
+    res += "NarHash: " + narHash.to_string(Base::Base32) + "\n";
     res += "NarSize: " + std::to_string(narSize) + "\n";
 
     res += "References: " + concatStringsSep(" ", shortRefs()) + "\n";
diff --git a/src/libstore/optimise-store.cc b/src/libstore/optimise-store.cc
index 8ac382e9d..5c01e1b3b 100644
--- a/src/libstore/optimise-store.cc
+++ b/src/libstore/optimise-store.cc
@@ -57,7 +57,7 @@ LocalStore::InodeHash LocalStore::loadInodeHash()
     }
     if (errno) throw SysError(format("reading directory '%1%'") % linksDir);
 
-    printMsg(lvlTalkative, format("loaded %1% hash inodes") % inodeHash.size());
+    printMsg(Verbosity::Talkative, format("loaded %1% hash inodes") % inodeHash.size());
 
     return inodeHash;
 }
@@ -149,11 +149,11 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
        Also note that if `path' is a symlink, then we're hashing the
        contents of the symlink (i.e. the result of readlink()), not
        the contents of the target (which may not even exist). */
-    Hash hash = hashPath(htSHA256, path).first;
+    Hash hash = hashPath(HashType::SHA256, path).first;
     debug(format("'%1%' has hash '%2%'") % path % hash.to_string());
 
     /* Check if this is a known hash. */
-    Path linkPath = linksDir + "/" + hash.to_string(Base32, false);
+    Path linkPath = linksDir + "/" + hash.to_string(Base::Base32, false);
 
  retry:
     if (!pathExists(linkPath)) {
@@ -199,7 +199,7 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
         goto retry;
     }
 
-    printMsg(lvlTalkative, format("linking '%1%' to '%2%'") % path % linkPath);
+    printMsg(Verbosity::Talkative, format("linking '%1%' to '%2%'") % path % linkPath);
 
     /* Make the containing directory writable, but only if it's not
        the store itself (we don't want or need to mess with its
@@ -246,13 +246,13 @@ void LocalStore::optimisePath_(Activity * act, OptimiseStats & stats,
     stats.blocksFreed += st.st_blocks;
 
     if (act)
-        act->result(resFileLinked, st.st_size, st.st_blocks);
+        act->result(ResultType::FileLinked, st.st_size, st.st_blocks);
 }
 
 
 void LocalStore::optimiseStore(OptimiseStats & stats)
 {
-    Activity act(*logger, actOptimiseStore);
+    Activity act(*logger, ActivityType::OptimiseStore);
 
     auto paths = queryAllValidPaths();
     InodeHash inodeHash = loadInodeHash();
@@ -265,7 +265,7 @@ void LocalStore::optimiseStore(OptimiseStats & stats)
         addTempRoot(i);
         if (!isValidPath(i)) continue; /* path was GC'ed, probably */
         {
-            Activity act(*logger, lvlTalkative, actUnknown, fmt("optimising path '%s'", printStorePath(i)));
+            Activity act(*logger, Verbosity::Talkative, ActivityType::Unknown, fmt("optimising path '%s'", printStorePath(i)));
             optimisePath_(&act, stats, realStoreDir + "/" + std::string(i.to_string()), inodeHash);
         }
         done++;
diff --git a/src/libstore/references.cc b/src/libstore/references.cc
index 102e15921..6652e1e26 100644
--- a/src/libstore/references.cc
+++ b/src/libstore/references.cc
@@ -54,7 +54,7 @@ struct RefScanSink : Sink
 
     string tail;
 
-    RefScanSink() : hashSink(htSHA256) { }
+    RefScanSink() : hashSink(HashType::SHA256) { }
 
     void operator () (const unsigned char * data, size_t len);
 };
@@ -96,7 +96,7 @@ PathSet scanForReferences(const string & path,
         string s = string(baseName, 0, pos);
         assert(s.size() == refLength);
         assert(backMap.find(s) == backMap.end());
-        // parseHash(htSHA256, s);
+        // parseHash(HashType::SHA256, s);
         sink.hashes.insert(s);
         backMap[s] = i;
     }
diff --git a/src/libstore/remote-store.cc b/src/libstore/remote-store.cc
index 8c55da268..3fc7ddfc0 100644
--- a/src/libstore/remote-store.cc
+++ b/src/libstore/remote-store.cc
@@ -177,11 +177,11 @@ void RemoteStore::setOptions(Connection & conn)
        << settings.keepFailed
        << settings.keepGoing
        << settings.tryFallback
-       << verbosity
+       << (uint64_t) verbosity
        << settings.maxBuildJobs
        << settings.maxSilentTime
        << true
-       << (settings.verboseBuild ? lvlError : lvlVomit)
+       << (uint64_t) (settings.verboseBuild ? Verbosity::Error : Verbosity::Vomit)
        << 0 // obsolete log type
        << 0 /* obsolete print build trace */
        << settings.buildCores
@@ -375,7 +375,7 @@ void RemoteStore::queryPathInfoUncached(const StorePath & path,
             info = std::make_shared<ValidPathInfo>(path.clone());
             auto deriver = readString(conn->from);
             if (deriver != "") info->deriver = parseStorePath(deriver);
-            info->narHash = Hash(readString(conn->from), htSHA256);
+            info->narHash = Hash(readString(conn->from), HashType::SHA256);
             info->references = readStorePaths<StorePathSet>(*this, conn->from);
             conn->from >> info->registrationTime >> info->narSize;
             if (GET_PROTOCOL_MINOR(conn->daemonVersion) >= 16) {
@@ -471,7 +471,7 @@ void RemoteStore::addToStore(const ValidPathInfo & info, Source & source,
         conn->to << wopAddToStoreNar
                  << printStorePath(info.path)
                  << (info.deriver ? printStorePath(*info.deriver) : "")
-                 << info.narHash.to_string(Base16, false);
+                 << info.narHash.to_string(Base::Base16, false);
         writeStorePaths(*this, conn->to, info.references);
         conn->to << info.registrationTime << info.narSize
                  << info.ultimate << info.sigs << info.ca
@@ -493,7 +493,7 @@ StorePath RemoteStore::addToStore(const string & name, const Path & _srcPath,
     Path srcPath(absPath(_srcPath));
 
     conn->to << wopAddToStore << name
-       << ((hashAlgo == htSHA256 && recursive) ? 0 : 1) /* backwards compatibility hack */
+       << ((hashAlgo == HashType::SHA256 && recursive) ? 0 : 1) /* backwards compatibility hack */
        << (recursive ? 1 : 0)
        << printHashType(hashAlgo);
 
diff --git a/src/libstore/remote-store.hh b/src/libstore/remote-store.hh
index f301a97d8..62cff8e3f 100644
--- a/src/libstore/remote-store.hh
+++ b/src/libstore/remote-store.hh
@@ -65,7 +65,7 @@ public:
         std::shared_ptr<FSAccessor> accessor) override;
 
     StorePath addToStore(const string & name, const Path & srcPath,
-        bool recursive = true, HashType hashAlgo = htSHA256,
+        bool recursive = true, HashType hashAlgo = HashType::SHA256,
         PathFilter & filter = defaultPathFilter, RepairFlag repair = NoRepair) override;
 
     StorePath addTextToStore(const string & name, const string & s,
diff --git a/src/libstore/s3-binary-cache-store.cc b/src/libstore/s3-binary-cache-store.cc
index f2e4b63e0..fb56ee62e 100644
--- a/src/libstore/s3-binary-cache-store.cc
+++ b/src/libstore/s3-binary-cache-store.cc
@@ -68,9 +68,9 @@ static void initAWS()
            shared.cc), so don't let aws-sdk-cpp override it. */
         options.cryptoOptions.initAndCleanupOpenSSL = false;
 
-        if (verbosity >= lvlDebug) {
+        if (verbosity >= Verbosity::Debug) {
             options.loggingOptions.logLevel =
-                verbosity == lvlDebug
+                verbosity == Verbosity::Debug
                 ? Aws::Utils::Logging::LogLevel::Debug
                 : Aws::Utils::Logging::LogLevel::Trace;
             options.loggingOptions.logger_create_fn = [options]() {
diff --git a/src/libstore/ssh.cc b/src/libstore/ssh.cc
index 84548a6e4..f61c094a2 100644
--- a/src/libstore/ssh.cc
+++ b/src/libstore/ssh.cc
@@ -58,7 +58,7 @@ std::unique_ptr<SSHMaster::Connection> SSHMaster::startCommand(const std::string
             addCommonSSHOpts(args);
             if (socketPath != "")
                 args.insert(args.end(), {"-S", socketPath});
-            if (verbosity >= lvlChatty)
+            if (verbosity >= Verbosity::Chatty)
                 args.push_back("-v");
         }
 
@@ -110,7 +110,7 @@ Path SSHMaster::startMaster()
             , "-o", "LocalCommand=echo started"
             , "-o", "PermitLocalCommand=yes"
             };
-        if (verbosity >= lvlChatty)
+        if (verbosity >= Verbosity::Chatty)
             args.push_back("-v");
         addCommonSSHOpts(args);
         execvp(args.begin()->c_str(), stringsToCharPtrs(args).data());
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index b9e894a9a..98475fd4c 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -141,8 +141,8 @@ StorePath Store::makeStorePath(const string & type,
     const Hash & hash, std::string_view name) const
 {
     /* e.g., "source:sha256:1abc...:/nix/store:foo.tar.gz" */
-    string s = type + ":" + hash.to_string(Base16) + ":" + storeDir + ":" + std::string(name);
-    auto h = compressHash(hashString(htSHA256, s), 20);
+    string s = type + ":" + hash.to_string(Base::Base16) + ":" + storeDir + ":" + std::string(name);
+    auto h = compressHash(hashString(HashType::SHA256, s), 20);
     return StorePath::make(h.hash, name);
 }
 
@@ -177,13 +177,13 @@ StorePath Store::makeFixedOutputPath(
     const StorePathSet & references,
     bool hasSelfReference) const
 {
-    if (hash.type == htSHA256 && recursive) {
+    if (hash.type == HashType::SHA256 && recursive) {
         return makeStorePath(makeType(*this, "source", references, hasSelfReference), hash, name);
     } else {
         assert(references.empty());
-        return makeStorePath("output:out", hashString(htSHA256,
+        return makeStorePath("output:out", hashString(HashType::SHA256,
                 "fixed:out:" + (recursive ? (string) "r:" : "") +
-                hash.to_string(Base16) + ":"), name);
+                hash.to_string(Base::Base16) + ":"), name);
     }
 }
 
@@ -191,7 +191,7 @@ StorePath Store::makeFixedOutputPath(
 StorePath Store::makeTextPath(std::string_view name, const Hash & hash,
     const StorePathSet & references) const
 {
-    assert(hash.type == htSHA256);
+    assert(hash.type == HashType::SHA256);
     /* Stuff the references (if any) into the type.  This is a bit
        hacky, but we can't put them in `s' since that would be
        ambiguous. */
@@ -210,7 +210,7 @@ std::pair<StorePath, Hash> Store::computeStorePathForPath(std::string_view name,
 StorePath Store::computeStorePathForText(const string & name, const string & s,
     const StorePathSet & references) const
 {
-    return makeTextPath(name, hashString(htSHA256, s), references);
+    return makeTextPath(name, hashString(HashType::SHA256, s), references);
 }
 
 
@@ -423,7 +423,7 @@ string Store::makeValidityRegistration(const StorePathSet & paths,
         auto info = queryPathInfo(i);
 
         if (showHash) {
-            s += info->narHash.to_string(Base16, false) + "\n";
+            s += info->narHash.to_string(Base::Base16, false) + "\n";
             s += (format("%1%\n") % info->narSize).str();
         }
 
@@ -561,7 +561,7 @@ void copyStorePath(ref<Store> srcStore, ref<Store> dstStore,
     auto srcUri = srcStore->getUri();
     auto dstUri = dstStore->getUri();
 
-    Activity act(*logger, lvlInfo, actCopyPath,
+    Activity act(*logger, Verbosity::Info, ActivityType::CopyPath,
         srcUri == "local" || srcUri == "daemon"
         ? fmt("copying path '%s' to '%s'", srcStore->printStorePath(storePath), dstUri)
           : dstUri == "local" || dstUri == "daemon"
@@ -578,7 +578,7 @@ void copyStorePath(ref<Store> srcStore, ref<Store> dstStore,
         StringSink sink;
         srcStore->narFromPath({storePath}, sink);
         auto info2 = make_ref<ValidPathInfo>(*info);
-        info2->narHash = hashString(htSHA256, *sink.s);
+        info2->narHash = hashString(HashType::SHA256, *sink.s);
         if (!info->narSize) info2->narSize = sink.s->size();
         if (info->ultimate) info2->ultimate = false;
         info = info2;
@@ -620,7 +620,7 @@ void copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & st
 
     if (missing.empty()) return;
 
-    Activity act(*logger, lvlInfo, actCopyPaths, fmt("copying %d paths", missing.size()));
+    Activity act(*logger, Verbosity::Info, ActivityType::CopyPaths, fmt("copying %d paths", missing.size()));
 
     std::atomic<size_t> nrDone{0};
     std::atomic<size_t> nrFailed{0};
@@ -646,7 +646,7 @@ void copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & st
             auto info = srcStore->queryPathInfo(srcStore->parseStorePath(storePath));
 
             bytesExpected += info->narSize;
-            act.setExpected(actCopyPath, bytesExpected);
+            act.setExpected(ActivityType::CopyPath, bytesExpected);
 
             return srcStore->printStorePathSet(info->references);
         },
@@ -665,7 +665,7 @@ void copyPaths(ref<Store> srcStore, ref<Store> dstStore, const StorePathSet & st
                     nrFailed++;
                     if (!settings.keepGoing)
                         throw e;
-                    logger->log(lvlError, fmt("could not copy %s: %s", storePathS, e.what()));
+                    logger->log(Verbosity::Error, fmt("could not copy %s: %s", storePathS, e.what()));
                     showProgress();
                     return;
                 }
@@ -711,7 +711,7 @@ std::optional<ValidPathInfo> decodeValidPathInfo(const Store & store, std::istre
     if (hashGiven) {
         string s;
         getline(str, s);
-        info.narHash = Hash(s, htSHA256);
+        info.narHash = Hash(s, HashType::SHA256);
         getline(str, s);
         if (!string2Int(s, info.narSize)) throw Error("number expected");
     }
@@ -754,7 +754,7 @@ std::string ValidPathInfo::fingerprint(const Store & store) const
             store.printStorePath(path));
     return
         "1;" + store.printStorePath(path) + ";"
-        + narHash.to_string(Base32) + ";"
+        + narHash.to_string(Base::Base32) + ";"
         + std::to_string(narSize) + ";"
         + concatStringsSep(",", store.printStorePathSet(references));
 }
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index 0fa59be6a..4247367b5 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -359,7 +359,7 @@ public:
        path and the cryptographic hash of the contents of srcPath. */
     std::pair<StorePath, Hash> computeStorePathForPath(std::string_view name,
         const Path & srcPath, bool recursive = true,
-        HashType hashAlgo = htSHA256, PathFilter & filter = defaultPathFilter) const;
+        HashType hashAlgo = HashType::SHA256, PathFilter & filter = defaultPathFilter) const;
 
     /* Preparatory part of addTextToStore().
 
@@ -462,12 +462,12 @@ public:
        The function object `filter' can be used to exclude files (see
        libutil/archive.hh). */
     virtual StorePath addToStore(const string & name, const Path & srcPath,
-        bool recursive = true, HashType hashAlgo = htSHA256,
+        bool recursive = true, HashType hashAlgo = HashType::SHA256,
         PathFilter & filter = defaultPathFilter, RepairFlag repair = NoRepair) = 0;
 
     // FIXME: remove?
     virtual StorePath addToStoreFromDump(const string & dump, const string & name,
-        bool recursive = true, HashType hashAlgo = htSHA256, RepairFlag repair = NoRepair)
+        bool recursive = true, HashType hashAlgo = HashType::SHA256, RepairFlag repair = NoRepair)
     {
         throw Error("addToStoreFromDump() is not supported by this store");
     }
@@ -561,7 +561,7 @@ public:
        each path is included. */
     void pathInfoToJSON(JSONPlaceholder & jsonOut, const StorePathSet & storePaths,
         bool includeImpureInfo, bool showClosureSize,
-        Base hashBase = Base32,
+        Base hashBase = Base::Base32,
         AllowInvalidFlag allowInvalid = DisallowInvalid);
 
     /* Return the size of the closure of the specified path, that is,