Improve API's metadata list caching

Don't create two copies of the lists on load, instead internally copy
their data when calling EvalAllConditions for the first time.

src/api/api_database.cpp

@@ -64,17 +64,15 @@ void ApiDatabase::LoadLists(const std::string& masterlistPath,
   }
 
   game_.GetMasterlist() = temp;
-  unevaluatedMasterlist_ = temp;
   game_.GetUserlist() = userTemp;
-  unevaluatedUserlist_ = userTemp;
 }
 
 void ApiDatabase::EvalLists() {
   // Clear caches before evaluating conditions.
   game_.ClearCachedConditions();
 
-  Masterlist temp = unevaluatedMasterlist_;
-  MetadataList userTemp = unevaluatedUserlist_;
+  Masterlist temp = game_.GetMasterlist();
+  MetadataList userTemp = game_.GetUserlist();
 
   // Refresh active plugins before evaluating conditions.
   temp.EvalAllConditions(game_);
@@ -107,7 +105,6 @@ bool ApiDatabase::UpdateMasterlist(const std::string& masterlistPath,
   Masterlist masterlist;
   if (masterlist.Update(masterlistPath, remoteURL, remoteBranch)) {
     game_.GetMasterlist() = masterlist;
-    unevaluatedMasterlist_ = masterlist;
     return true;
   }
 

src/api/api_database.h

@@ -72,9 +72,6 @@ struct ApiDatabase : public DatabaseInterface {
   void DiscardAllUserMetadata();
 private:
   Game& game_;
-
-  Masterlist unevaluatedMasterlist_;
-  MetadataList unevaluatedUserlist_;
 };
 }
 

src/api/metadata_list.cpp

@@ -154,20 +154,33 @@ void MetadataList::AppendMessage(const Message& message) {
 
 void MetadataList::EvalAllConditions(Game& game) {
   ConditionEvaluator evaluator(&game);
-  std::unordered_set<PluginMetadata> replacementSet;
-  for (auto &plugin : plugins_) {
-    replacementSet.insert(evaluator.evaluateAll(plugin));
+
+  if (unevaluatedPlugins_.empty())
+    unevaluatedPlugins_.swap(plugins_);
+  else
+    plugins_.clear();
+
+  for (const auto& plugin : unevaluatedPlugins_) {
+    plugins_.insert(evaluator.evaluateAll(plugin));
   }
-  plugins_ = replacementSet;
-  for (auto &plugin : regexPlugins_) {
+
+  if (unevaluatedRegexPlugins_.empty())
+    unevaluatedRegexPlugins_ = regexPlugins_;
+  else
+    regexPlugins_ = unevaluatedRegexPlugins_;
+
+  for (auto& plugin : regexPlugins_) {
     plugin = evaluator.evaluateAll(plugin);
   }
 
-  for (auto it = std::begin(messages_); it != std::end(messages_);) {
-    if (!evaluator.evaluate(it->GetCondition()))
-      it = messages_.erase(it);
-    else
-      ++it;
+  if (unevaluatedMessages_.empty())
+    unevaluatedMessages_.swap(messages_);
+  else
+    messages_.clear();
+
+  for (const auto& message : unevaluatedMessages_) {
+    if (evaluator.evaluate(message.GetCondition()))
+      messages_.push_back(message);
   }
 }
 }

src/api/metadata_list.h

@@ -64,6 +64,10 @@ protected:
   std::unordered_set<PluginMetadata> plugins_;
   std::list<PluginMetadata> regexPlugins_;
   std::vector<Message> messages_;
+
+  std::unordered_set<PluginMetadata> unevaluatedPlugins_;
+  std::list<PluginMetadata> unevaluatedRegexPlugins_;
+  std::vector<Message> unevaluatedMessages_;
 };
 }