[Base] Add cvar class, a better, more flexible implementation of storing configuration variables than gflags

src/xenia/base/cvar.cc

@@ -0,0 +1,56 @@
+#include "cvar.h"
+
+namespace cvar {
+cxxopts::Options options("xenia", "Xbox 360 Emulator");
+std::map<std::string, ICommandVar*>* CmdVars;
+std::map<std::string, IConfigVar*>* ConfigVars;
+
+void PrintHelpAndExit() {
+  std::cout << options.help({""}) << std::endl;
+  std::cout << "For the full list of command line arguments, see xenia.cfg."
+            << std::endl;
+  exit(0);
+}
+
+void ParseLaunchArguments(int argc, char** argv) {
+  options.add_options()("help", "Prints help and exit.");
+  if (!CmdVars) CmdVars = new std::map<std::string, ICommandVar*>();
+  if (!ConfigVars) ConfigVars = new std::map<std::string, IConfigVar*>();
+  for (auto& it : *CmdVars) {
+    auto cmdVar = it.second;
+    cmdVar->AddToLaunchOptions(&options);
+  }
+  std::vector<IConfigVar*> vars;
+  for (const auto& s : *ConfigVars) vars.push_back(s.second);
+
+  for (auto& it : *ConfigVars) {
+    auto configVar = it.second;
+    configVar->AddToLaunchOptions(&options);
+  }
+  try {
+    options.positional_help("[Path to .iso/.xex]");
+    options.parse_positional({"target"});
+
+    auto result = options.parse(argc, argv);
+    if (result.count("help")) {
+      PrintHelpAndExit();
+    }
+    for (auto& it : *CmdVars) {
+      auto cmdVar = static_cast<ICommandVar*>(it.second);
+      if (result.count(cmdVar->GetName())) {
+        cmdVar->LoadFromLaunchOptions(&result);
+      }
+    }
+    for (auto& it : *ConfigVars) {
+      auto configVar = static_cast<IConfigVar*>(it.second);
+      if (result.count(configVar->GetName())) {
+        configVar->LoadFromLaunchOptions(&result);
+      }
+    }
+  } catch (const cxxopts::OptionException& e) {
+    std::cout << e.what() << std::endl;
+    PrintHelpAndExit();
+  }
+}
+
+}  // namespace cvar