Make IPC opt-in and configurable

1 files changed, 135 insertions, 29 deletions

@@ -15,18 +15,21 @@
 #include <tuple>
 #include <wswrap.hpp>
 
+#include "ap_state.h"
 #include "logger.h"
 #include "tracker_frame.h"
 
 namespace {
 
-constexpr const char* kIpcAddress = "ws://127.0.0.1:41253";
-
 struct IPCState {
   std::mutex state_mutex;
   TrackerFrame* tracker_frame = nullptr;
 
   // Protected state
+  bool initialized = false;
+  std::string address;
+  bool should_disconnect = false;
+
   std::optional<std::string> status_message;
 
   bool slot_matches = false;
@@ -38,16 +41,27 @@ struct IPCState {
   std::optional<std::tuple<int, int>> player_position;
   std::set<std::string> solved_panels;
 
-  int backoff_amount = 0;
-
   // Thread state
   std::unique_ptr<wswrap::WS> ws;
   bool connected = false;
 
-  void Start(TrackerFrame* frame) {
-    tracker_frame = frame;
+  void SetTrackerFrame(TrackerFrame* frame) { tracker_frame = frame; }
+
+  void Connect(std::string a) {
+    // This is the main concurrency concern, as it mutates protected state in an
+    // important way. Thread() is documented with how it interacts with this
+    // function.
+    std::lock_guard state_guard(state_mutex);
+
+    if (!initialized) {
+      std::thread([this]() { Thread(); }).detach();
 
-    std::thread([this]() { Thread(); }).detach();
+      initialized = true;
+    } else if (address != a) {
+      should_disconnect = true;
+    }
+
+    address = a;
   }
 
   std::optional<std::string> GetStatusMessage() {
@@ -57,6 +71,13 @@ struct IPCState {
   }
 
   void SetTrackerSlot(std::string server, std::string user) {
+    // This is function is called from the APState thread, not the main thread,
+    // and it mutates protected state. It only really competes with OnMessage(),
+    // when a "Connect" message is received. If this is called right before,
+    // and the tracker slot does not match the old game slot, it will initiate a
+    // disconnect, and then the OnMessage() handler will see should_disconnect
+    // and stop processing the "Connect" message. If this is called right after
+    // and the slot does not match, IPC will disconnect, which is tolerable.
     std::lock_guard state_guard(state_mutex);
 
     tracker_ap_server = std::move(server);
@@ -64,7 +85,10 @@ struct IPCState {
 
     CheckIfSlotMatches();
 
-    backoff_amount = 0;
+    if (!slot_matches) {
+      should_disconnect = true;
+      address.clear();
+    }
   }
 
   bool IsConnected() {
@@ -88,54 +112,126 @@ struct IPCState {
  private:
   void Thread() {
     for (;;) {
-      player_position = std::nullopt;
-
-      TrackerLog("Looking for game over IPC...");
+      SetStatusMessage("Disconnected from game.");
 
+      // initialized is definitely true because it is set to true when the thread
+      // is created and only set to false within this block, when the thread is
+      // killed. Thus, a call to Connect would always at most set
+      // should_disconnect and address. If this happens before this block, it is
+      // as if we are starting from a new thread anyway because should_disconnect
+      // is immediately reset. If a call to Connect happens after this block,
+      // then a connection attempt will be made to the wrong address, but the
+      // thread will grab the mutex right after this and back out the wrong
+      // connection.
+      std::string ipc_address;
       {
         std::lock_guard state_guard(state_mutex);
-        backoff_amount = 0;
-      }
 
-      while (!TryConnect() || !connected) {
-        int backoff_limit;
-        {
-          std::lock_guard state_guard(state_mutex);
-          backoff_limit = (backoff_amount + 1) * 10;
+        should_disconnect = false;
+
+        slot_matches = false;
+        game_ap_server.clear();
+        game_ap_user.clear();
+
+        player_position = std::nullopt;
+        solved_panels.clear();
+
+        if (address.empty()) {
+          initialized = false;
+          return;
         }
 
+        ipc_address = address;
+      }
+
+      int backoff_amount = 0;
+
+      SetStatusMessage("Connecting to game...");
+      TrackerLog(fmt::format("Looking for game over IPC ({})...", ipc_address));
+
+      while (!TryConnect(ipc_address) || !connected) {
+        int backoff_limit = (backoff_amount + 1) * 10;
+
         for (int i = 0; i < backoff_limit && !connected; i++) {
+          // If Connect is called right before this block, we will see and handle
+          // should_disconnect. If it is called right after, we will do one bad
+          // poll, one sleep, and then grab the mutex again right after.
+          {
+            std::lock_guard state_guard(state_mutex);
+            if (should_disconnect) {
+              break;
+            }
+          }
+
           ws->poll();
 
           // Back off
           std::this_thread::sleep_for(std::chrono::milliseconds(100));
         }
 
+        backoff_amount++;
+
+        // If Connect is called right before this block, we will see and handle
+        // should_disconnect. If it is called right after, and the connection
+        // was unsuccessful, we will grab the mutex after one bad connection
+        // attempt. If the connection was successful, we grab the mutex right
+        // after exiting the loop.
         {
           std::lock_guard state_guard(state_mutex);
-          backoff_amount = std::min(9, backoff_amount + 1);
 
-          if (!connected) {
-            TrackerLog(fmt::format("Retrying IPC in {} second(s)...",
-                                   backoff_amount + 1));
+          if (should_disconnect) {
+            break;
+          } else if (!connected) {
+            if (backoff_amount >= 10) {
+              should_disconnect = true;
+              address.clear();
+
+              TrackerLog("Giving up on IPC.");
+              SetStatusMessage("Disconnected from game.");
+
+              wxMessageBox("Connection to Lingo timed out.",
+                           "Connection failed", wxOK | wxICON_ERROR);
+
+              break;
+            } else {
+              TrackerLog(fmt::format("Retrying IPC in {} second(s)...",
+                                     backoff_amount + 1));
+            }
           }
         }
       }
 
+      // Pretty much every lock guard in the thread is the same. We check for
+      // should_disconnect, and if it gets set directly after the block, we do
+      // minimal bad work before checking for it again.
+      {
+        std::lock_guard state_guard(state_mutex);
+        if (should_disconnect) {
+          ws.reset();
+          continue;
+        }
+      }
+
       while (connected) {
         ws->poll();
 
         std::this_thread::sleep_for(std::chrono::milliseconds(100));
-      }
 
-      SetStatusMessage("Disconnected from game.");
+        {
+          std::lock_guard state_guard(state_mutex);
+          if (should_disconnect) {
+            ws.reset();
+            break;
+          }
+        }
+      }
     }
   }
 
-  bool TryConnect() {
+  bool TryConnect(std::string ipc_address) {
     try {
       ws = std::make_unique<wswrap::WS>(
-          kIpcAddress, [this]() { OnConnect(); }, [this]() { OnClose(); },
+          ipc_address, [this]() { OnConnect(); }, [this]() { OnClose(); },
           [this](const std::string& s) { OnMessage(s); },
           [this](const std::string& s) { OnError(s); });
       return true;
@@ -174,11 +270,19 @@ struct IPCState {
 
     if (msg["cmd"] == "Connect") {
       std::lock_guard state_guard(state_mutex);
+      if (should_disconnect) {
+        return;
+      }
 
       game_ap_server = msg["slot"]["server"];
       game_ap_user = msg["slot"]["player"];
 
       CheckIfSlotMatches();
+
+      if (!slot_matches) {
+        tracker_frame->ConnectToAp(game_ap_server, game_ap_user,
+                                   msg["slot"]["password"]);
+      }
     } else if (msg["cmd"] == "UpdatePosition") {
       std::lock_guard state_guard(state_mutex);
 
@@ -207,8 +311,6 @@ struct IPCState {
       status_message = "Connected to game.";
 
       Sync();
-    } else if (tracker_ap_server.empty()) {
-      status_message = std::nullopt;
     } else if (connected) {
       status_message = "Local game doesn't match AP slot.";
     }
@@ -240,7 +342,11 @@ IPCState& GetState() {
 
 }  // namespace
 
-void IPC_Start(TrackerFrame* tracker_frame) { GetState().Start(tracker_frame); }
+void IPC_SetTrackerFrame(TrackerFrame* tracker_frame) {
+  GetState().SetTrackerFrame(tracker_frame);
+}
+
+void IPC_Connect(std::string address) { GetState().Connect(address); }
 
 std::optional<std::string> IPC_GetStatusMessage() {
   return GetState().GetStatusMessage();