drop checkInterrupt from ThreadPool items

all of them block on a promise very soon after starting. only
queryValidPaths needs to make sure not to swallow Interrupted
exceptions to exit quickly instead of trying all paths first.

Change-Id: I4f99f5d75d7057bad109dc0131aa58e84275e362

lix/libstore/binary-cache-store.cc

@@ -226,8 +226,6 @@ try {
                               std::string member,
                               std::string key,
                               std::string target) {
-                checkInterrupt();
-
                 JSON json;
                 json["archive"] = target;
                 json["member"] = member;

lix/libstore/store-api.cc

@@ -760,8 +760,6 @@ try {
     ThreadPool pool{"queryValidPaths pool"};
 
     auto doQuery = [&](AsyncIoRoot & aio, const StorePath & path) {
-        checkInterrupt();
-
         bool exists = false;
         std::exception_ptr newExc{};
 
@@ -769,6 +767,8 @@ try {
             aio.blockOn(queryPathInfo(path));
             exists = true;
         } catch (InvalidPath &) {
+        } catch (Interrupted &) {
+            throw;
         } catch (...) {
             newExc = std::current_exception();
         }

lix/nix/sigs.cc

@@ -46,9 +46,6 @@ struct CmdCopySigs : StorePathsCommand
         std::atomic<size_t> added{0};
 
         auto doPath = [&](AsyncIoRoot & aio, const Path & storePathS) {
-
-            checkInterrupt();
-
             auto storePath = store->parseStorePath(storePathS);
 
             auto info = aio.blockOn(store->queryPathInfo(storePath));
@@ -124,9 +121,6 @@ struct CmdSign : StorePathsCommand
         std::atomic<size_t> added{0};
 
         auto doPath = [&](AsyncIoRoot & aio, const Path & storePathS) {
-
-            checkInterrupt();
-
             auto storePath = store->parseStorePath(storePathS);
 
             auto info = aio.blockOn(store->queryPathInfo(storePath));

lix/nix/verify.cc

@@ -86,8 +86,6 @@ struct CmdVerify : StorePathsCommand
 
         auto doPath = [&](AsyncIoRoot & aio, const StorePath & storePath) {
             try {
-                checkInterrupt();
-
                 MaintainCount<std::atomic<size_t>> mcActive(active);
                 update();
 
@@ -145,7 +143,9 @@ struct CmdVerify : StorePathsCommand
                             if (validSigs >= actualSigsNeeded) break;
                             try {
                                 auto info2 = aio.blockOn(store2->queryPathInfo(info->path));
-                                if (info2->isContentAddressed(*store)) validSigs = ValidPathInfo::maxSigs;
+                                if (info2->isContentAddressed(*store)) {
+                                    validSigs = ValidPathInfo::maxSigs;
+                                }
                                 doSigs(info2->sigs);
                             } catch (InvalidPath &) {
                             } catch (Error & e) {