timeline refactor, bit broken rn

src/loader.cpp

@@ -1,5 +1,7 @@
 #include "loader.h"
 
+#include <cstdint>
+
 #include <imgui/backends/imgui_impl_opengl3.h>
 #include <imgui/backends/imgui_impl_sdl3.h>
 
@@ -8,11 +10,57 @@
 #include "filesystem_.h"
 #include "log.h"
 
+#include "socket.h"
+
 using namespace anm2ed::types;
 using namespace anm2ed::util;
 
 namespace anm2ed
 {
+  constexpr auto SOCKET_ADDRESS = "127.0.0.1";
+  constexpr auto SOCKET_PORT = 11414;
+
+  namespace
+  {
+    bool socket_paths_send(Socket& socket, const std::vector<std::string>& paths)
+    {
+      uint32_t count = htonl(static_cast<uint32_t>(paths.size()));
+      if (!socket.send(&count, sizeof(count))) return false;
+
+      for (const auto& path : paths)
+      {
+        uint32_t length = htonl(static_cast<uint32_t>(path.size()));
+        if (!socket.send(&length, sizeof(length))) return false;
+        if (!path.empty() && !socket.send(path.data(), path.size())) return false;
+      }
+
+      return true;
+    }
+
+    std::vector<std::string> socket_paths_receive(Socket& socket)
+    {
+      uint32_t count{};
+      if (!socket.receive(&count, sizeof(count))) return {};
+      count = ntohl(count);
+
+      std::vector<std::string> paths;
+      paths.reserve(count);
+
+      for (uint32_t i = 0; i < count; ++i)
+      {
+        uint32_t length{};
+        if (!socket.receive(&length, sizeof(length))) return {};
+        length = ntohl(length);
+
+        std::string path(length, '\0');
+        if (length > 0 && !socket.receive(path.data(), length)) return {};
+        paths.emplace_back(std::move(path));
+      }
+
+      return paths;
+    }
+  }
+
   std::string Loader::settings_path()
   {
     return filesystem::path_preferences_get() + "settings.ini";
@@ -23,6 +71,45 @@ namespace anm2ed
     for (int i = 1; i < argc; i++)
       arguments.emplace_back(argv[i]);
 
+    Socket testSocket;
+    if (!testSocket.open(SERVER))
+      logger.warning(std::format("Failed to open socket; single instancing will not work."));
+
+    bool isPrimaryInstance = false;
+
+    if (testSocket.bind({SOCKET_ADDRESS, SOCKET_PORT}))
+    {
+      socket = std::move(testSocket);
+
+      if (!socket.listen())
+        logger.warning("Could not listen on socket; single instancing disabled.");
+      else
+      {
+        isPrimaryInstance = true;
+        isSocketThread = true;
+        logger.info(std::format("Opened socket at {}:{}", SOCKET_ADDRESS, SOCKET_PORT));
+      }
+    }
+    else
+    {
+      logger.info(std::format("Existing instance of program exists; passing arguments..."));
+      Socket clientSocket;
+      if (!clientSocket.open(CLIENT))
+        logger.warning("Could not open client socket to forward arguments.");
+      else if (!clientSocket.connect({SOCKET_ADDRESS, SOCKET_PORT}))
+        logger.warning("Could not connect to existing instance.");
+      else if (!socket_paths_send(clientSocket, arguments))
+        logger.warning("Failed to transfer arguments to existing instance.");
+      else
+        logger.info("Sent arguments to existing instance. Exiting.");
+
+      if (!isPrimaryInstance)
+      {
+        isError = true;
+        return;
+      }
+    }
+
     settings = Settings(settings_path());
 
     if (!SDL_Init(SDL_INIT_VIDEO))
@@ -93,10 +180,54 @@ namespace anm2ed
     io.ConfigWindowsMoveFromTitleBarOnly = true;
 
     ImGui::LoadIniSettingsFromDisk(settings_path().c_str());
+
+    if (isSocketThread)
+    {
+      isSocketRunning = true;
+      socketThread = std::thread(
+          [this]()
+          {
+            while (isSocketRunning)
+            {
+              auto client = socket.accept();
+              if (!client.is_valid())
+              {
+                if (!isSocketRunning) break;
+                continue;
+              }
+
+              auto paths = socket_paths_receive(client);
+              for (auto& path : paths)
+              {
+                if (path.empty()) continue;
+                SDL_Event event{};
+                event.type = SDL_EVENT_DROP_FILE;
+                event.drop.data = SDL_strdup(path.c_str());
+                event.drop.windowID = window ? SDL_GetWindowID(window) : 0;
+                SDL_PushEvent(&event);
+              }
+            }
+          });
+    }
   }
 
   Loader::~Loader()
   {
+    if (isSocketThread)
+    {
+      isSocketRunning = false;
+
+      if (socket.is_valid())
+      {
+        Socket wakeSocket;
+        if (wakeSocket.open(CLIENT) && wakeSocket.connect({SOCKET_ADDRESS, SOCKET_PORT}))
+          socket_paths_send(wakeSocket, {});
+      }
+
+      socket.close();
+      if (socketThread.joinable()) socketThread.join();
+    }
+
     if (ImGui::GetCurrentContext())
     {
       settings.save(settings_path(), ImGui::SaveIniSettingsToMemory(nullptr));
@@ -115,4 +246,4 @@ namespace anm2ed
       SDL_Quit();
     }
   }
-}
+}