Usb2Snes: fix race between data and connection update

black-sliver · Jul 29, 2024 · ce24865 · ce24865
1 parent eb92d9c
commit ce24865
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Showing 3 changed files with 53 additions and 7 deletions.
diff --git a/src/core/autotracker.h b/src/core/autotracker.h
@@ -215,12 +215,19 @@ class AutoTracker final : public LuaInterface<AutoTracker>{
                 _snes->connect();
             else
                 _snes->connect(_snesAddresses);
-            if (_snes->dostuff()) {
+
+            USB2SNES::Change changed = _snes->poll();
+            if (!!changed) {
                 int index = _backendIndex[_snes];
                 State oldState = _state[index];
                 bool wsConnected = _snes->wsConnected();
                 bool snesConnected = wsConnected ? _snes->snesConnected() : false;
 
+                if (!snesConnected && !!(changed & USB2SNES::Change::DATA)) {
+                    // fire data change before firing disconnect
+                    onDataChange.emit(this);
+                }
+
                 if (snesConnected) {
                     _state[index] = State::ConsoleConnected;
                 } else if (wsConnected) {
@@ -231,7 +238,10 @@ class AutoTracker final : public LuaInterface<AutoTracker>{
 
                 if (_state[index] != oldState) {
                     onStateChange.emit(this, index, _state[index]);
-                } else if (_state[index] == State::ConsoleConnected) {
+                }
+
+                if (snesConnected && !!(changed & USB2SNES::Change::DATA)) {
+                    // fire data change after firing connect
                     onDataChange.emit(this);
                 }
 

diff --git a/src/usb2snes/usb2snes.cpp b/src/usb2snes/usb2snes.cpp
@@ -448,17 +448,20 @@ bool USB2SNES::disconnect()
     std::this_thread::sleep_for(std::chrono::milliseconds(1));
     return true;
 }
-bool USB2SNES::dostuff()
+
+USB2SNES::Change USB2SNES::poll()
 {
-    bool res = false;
+    USB2SNES::Change res = USB2SNES::Change::NONE;
     {
         std::lock_guard<std::mutex> datalock(datamutex);
-        res |= data_changed;
+        if (data_changed)
+            res |= Change::DATA;
         data_changed = false;
     }
     {
         std::lock_guard<std::mutex> statelock(statemutex);
-        res |= state_changed;
+        if (state_changed)
+            res |= Change::STATE;
         state_changed = false;
     }
     return res;

diff --git a/src/usb2snes/usb2snes.h b/src/usb2snes/usb2snes.h
@@ -8,6 +8,7 @@
 #include <chrono>
 #include <vector>
 #include <string>
+#include <type_traits>
 
 class USB2SNES {
     public:
@@ -20,11 +21,17 @@ class USB2SNES {
             SA1,
         };
 
+        enum class Change : unsigned {
+            NONE = 0,
+            STATE = 1,
+            DATA = 2,
+        };
+
         USB2SNES(const std::string& appname);
         ~USB2SNES();
         bool connect(std::vector<std::string> uris = {QUSB2SNES_URI,LEGACY_URI});
         bool disconnect();
-        bool dostuff();
+        Change poll();
         static constexpr auto QUSB2SNES_URI = "ws://localhost:23074";
         static constexpr auto LEGACY_URI = "ws://localhost:8080";
         bool wsConnected();
@@ -159,5 +166,31 @@ T USB2SNES::readInt(uint32_t addr)
     return res;
 }
 
+static inline USB2SNES::Change operator|(USB2SNES::Change lhs, USB2SNES::Change rhs)
+{
+    return static_cast<USB2SNES::Change>(
+            static_cast<typename std::underlying_type<USB2SNES::Change>::type>(lhs) |
+            static_cast<typename std::underlying_type<USB2SNES::Change>::type>(rhs)
+    );
+}
+
+static inline USB2SNES::Change& operator|=(USB2SNES::Change& lhs, USB2SNES::Change rhs)
+{
+    return lhs = lhs | rhs;
+}
+
+static inline USB2SNES::Change operator&(USB2SNES::Change lhs, USB2SNES::Change rhs)
+{
+    return static_cast<USB2SNES::Change>(
+            static_cast<typename std::underlying_type<USB2SNES::Change>::type>(lhs) &
+            static_cast<typename std::underlying_type<USB2SNES::Change>::type>(rhs)
+    );
+}
+
+static inline bool operator!(USB2SNES::Change e) {
+    return e == static_cast<USB2SNES::Change>(0);
+}
+
+
 #endif // _USB2SNES_H_INCLUDED