SERVER-46154 Pull the InProgressLookup outside of ReadThroughCache

The InProgressLookup tracking already has quite complicated logic, so it
seems prudent to pull it into a separate class, outside of the
ReadThroughCache so it can be tested independently.

3 files changed, 15 insertions, 13 deletions

diff --git a/src/mongo/db/auth/authorization_manager_impl.cpp b/src/mongo/db/auth/authorization_manager_impl.cpp
index e3552ae7332..5f6e9ab1380 100644
--- a/src/mongo/db/auth/authorization_manager_impl.cpp
+++ b/src/mongo/db/auth/authorization_manager_impl.cpp
@@ -663,14 +663,14 @@ AuthorizationManagerImpl::AuthSchemaVersionCache::AuthSchemaVersionCache(
           1 /* cacheSize */),
       _externalState(externalState) {}
 
-boost::optional<int> AuthorizationManagerImpl::AuthSchemaVersionCache::_lookup(
-    OperationContext* opCtx, int unusedKey) {
+AuthorizationManagerImpl::AuthSchemaVersionCache::LookupResult
+AuthorizationManagerImpl::AuthSchemaVersionCache::_lookup(OperationContext* opCtx, int unusedKey) {
     invariant(unusedKey == 0);
 
     int authzVersion;
     uassertStatusOK(_externalState->getStoredAuthorizationVersion(opCtx, &authzVersion));
 
-    return authzVersion;
+    return LookupResult(authzVersion);
 }
 
 AuthorizationManagerImpl::UserCacheImpl::UserCacheImpl(
@@ -689,8 +689,9 @@ AuthorizationManagerImpl::UserCacheImpl::UserCacheImpl(
       _authSchemaVersionCache(authSchemaVersionCache),
       _externalState(externalState) {}
 
-boost::optional<User> AuthorizationManagerImpl::UserCacheImpl::_lookup(OperationContext* opCtx,
-                                                                       const UserRequest& userReq) {
+AuthorizationManagerImpl::UserCacheImpl::LookupResult
+AuthorizationManagerImpl::UserCacheImpl::_lookup(OperationContext* opCtx,
+                                                 const UserRequest& userReq) {
     LOGV2_DEBUG(20238, 1, "Getting user record", "user"_attr = userReq.name);
 
     // Number of times to retry a user document that fetches due to transient AuthSchemaIncompatible
@@ -713,7 +714,7 @@ boost::optional<User> AuthorizationManagerImpl::UserCacheImpl::_lookup(Operation
 
                 User user(userReq.name);
                 uassertStatusOK(initializeUserFromPrivilegeDocument(&user, userObj));
-                return user;
+                return LookupResult(std::move(user));
             }
             case schemaVersion24:
                 _authSchemaVersionCache->invalidateAll();
diff --git a/src/mongo/db/auth/authorization_manager_impl.h b/src/mongo/db/auth/authorization_manager_impl.h
index 17a3d731f1f..611aa427662 100644
--- a/src/mongo/db/auth/authorization_manager_impl.h
+++ b/src/mongo/db/auth/authorization_manager_impl.h
@@ -158,7 +158,7 @@ private:
         // Even though the dist cache permits for lookup to return boost::none for non-existent
         // values, the contract of the authorization manager is that it should throw an exception if
         // the value can not be loaded, so if it returns, the value will always be set.
-        boost::optional<int> _lookup(OperationContext* opCtx, int unusedKey);
+        LookupResult _lookup(OperationContext* opCtx, int unusedKey);
 
         Mutex _mutex =
             MONGO_MAKE_LATCH("AuthorizationManagerImpl::AuthSchemaVersionDistCache::_mutex");
@@ -181,7 +181,7 @@ private:
         // Even though the dist cache permits for lookup to return boost::none for non-existent
         // values, the contract of the authorization manager is that it should throw an exception if
         // the value can not be loaded, so if it returns, the value will always be set.
-        boost::optional<User> _lookup(OperationContext* opCtx, const UserRequest& user);
+        LookupResult _lookup(OperationContext* opCtx, const UserRequest& user);
 
         Mutex _mutex = MONGO_MAKE_LATCH("AuthorizationManagerImpl::UserDistCacheImpl::_mutex");
 
diff --git a/src/mongo/db/read_write_concern_defaults.cpp b/src/mongo/db/read_write_concern_defaults.cpp
index f33c78215a3..3c69751348a 100644
--- a/src/mongo/db/read_write_concern_defaults.cpp
+++ b/src/mongo/db/read_write_concern_defaults.cpp
@@ -237,11 +237,12 @@ ReadWriteConcernDefaults::~ReadWriteConcernDefaults() = default;
 ReadWriteConcernDefaults::Cache::Cache(ServiceContext* service,
                                        ThreadPoolInterface& threadPool,
                                        FetchDefaultsFn fetchDefaultsFn)
-    : ReadThroughCache(_mutex,
-                       service,
-                       threadPool,
-                       [this](OperationContext* opCtx, Type) { return lookup(opCtx); },
-                       1 /* cacheSize */),
+    : ReadThroughCache(
+          _mutex,
+          service,
+          threadPool,
+          [this](OperationContext* opCtx, Type) { return LookupResult(lookup(opCtx)); },
+          1 /* cacheSize */),
       _fetchDefaultsFn(std::move(fetchDefaultsFn)) {}
 
 boost::optional<RWConcernDefault> ReadWriteConcernDefaults::Cache::lookup(OperationContext* opCtx) {