libstore: asyncify getDefaultSubstituters

Change-Id: I078c5575f4941ab0d06ef9bf1e549b789e695afc

lix/libcmd/repl.cc

@@ -729,7 +729,7 @@ ProcessLineResult NixRepl::processLine(std::string line)
         Finally roModeReset([&]() {
             settings.readOnlyMode = false;
         });
-        auto subs = getDefaultSubstituters();
+        auto subs = state.aio.blockOn(getDefaultSubstituters());
 
         subs.push_front(evaluator.store);
 

lix/libstore/build/drv-output-substitution-goal.cc

@@ -34,7 +34,7 @@ try {
         co_return WorkResult{ecSuccess};
     }
 
-    subs = settings.useSubstitutes ? getDefaultSubstituters() : std::list<ref<Store>>();
+    subs = settings.useSubstitutes ? TRY_AWAIT(getDefaultSubstituters()) : std::list<ref<Store>>();
     co_return co_await tryNext();
 } catch (...) {
     co_return result::current_exception();

lix/libstore/build/substitution-goal.cc

@@ -62,7 +62,7 @@ try {
     if (settings.readOnlyMode)
         throw Error("cannot substitute path '%s' - no write access to the Nix store", worker.store.printStorePath(storePath));
 
-    subs = settings.useSubstitutes ? getDefaultSubstituters() : std::list<ref<Store>>();
+    subs = settings.useSubstitutes ? TRY_AWAIT(getDefaultSubstituters()) : std::list<ref<Store>>();
 
     BOOST_OUTCOME_CO_TRY(auto result, co_await tryNext());
     result.storePath = storePath;

lix/libstore/local-store.cc

@@ -1072,7 +1072,7 @@ try {
 
     StorePathSet res;
 
-    for (auto & sub : getDefaultSubstituters()) {
+    for (auto & sub : TRY_AWAIT(getDefaultSubstituters())) {
         if (remaining.empty()) break;
         if (sub->config().storeDir != config_.storeDir) continue;
         if (!sub->config().wantMassQuery) continue;

lix/libstore/misc.cc

@@ -251,7 +251,7 @@ struct QueryMissingContext
                     continue;
 
                 bool found = false;
-                for (auto &sub : getDefaultSubstituters()) {
+                for (auto &sub : aio.blockOn(getDefaultSubstituters())) {
                     auto realisation = sub->queryRealisation({hash, outputName});
                     if (!realisation)
                         continue;

lix/libstore/store-api.cc

@@ -607,7 +607,7 @@ StorePathSet Store::queryDerivationOutputs(const StorePath & path)
 kj::Promise<Result<void>> Store::querySubstitutablePathInfos(const StorePathCAMap & paths, SubstitutablePathInfos & infos)
 try {
     if (!settings.useSubstitutes) co_return result::success();
-    for (auto & sub : getDefaultSubstituters()) {
+    for (auto & sub : TRY_AWAIT(getDefaultSubstituters())) {
         for (auto & path : paths) {
             if (infos.count(path.first))
                 // Choose first succeeding substituter.
@@ -1566,8 +1566,8 @@ ref<Store> openStore(const std::string & uri_,
     throw Error("don't know how to open Nix store '%s'", uri_);
 }
 
-std::list<ref<Store>> getDefaultSubstituters()
-{
+kj::Promise<Result<std::list<ref<Store>>>> getDefaultSubstituters()
+try {
     static auto stores([]() {
         std::list<ref<Store>> stores;
 
@@ -1592,7 +1592,9 @@ std::list<ref<Store>> getDefaultSubstituters()
         return stores;
     } ());
 
-    return stores;
+    co_return stores;
+} catch (...) {
+    co_return result::current_exception();
 }
 
 std::vector<StoreFactory> * StoreImplementations::registered = 0;

lix/libstore/store-api.hh

@@ -1008,7 +1008,7 @@ ref<Store> openStore(const std::string & uri = settings.storeUri.get(),
  * @return the default substituter stores, defined by the
  * ‘substituters’ option and various legacy options.
  */
-std::list<ref<Store>> getDefaultSubstituters();
+kj::Promise<Result<std::list<ref<Store>>>> getDefaultSubstituters();
 
 struct StoreFactory
 {

lix/nix/log.cc

@@ -26,7 +26,7 @@ struct CmdLog : InstallableCommand
     {
         settings.readOnlyMode = true;
 
-        auto subs = getDefaultSubstituters();
+        auto subs = aio().blockOn(getDefaultSubstituters());
 
         subs.push_front(store);