From ca0a76af1a3671b17cb745293c87eaebe639d9bb Mon Sep 17 00:00:00 2001
From: Arisotura <thetotalworm@gmail.com>
Date: Sat, 11 Mar 2023 13:46:29 +0100
Subject: [PATCH] make cross-instance pause work without being a shitshow

---
 src/frontend/qt_sdl/IPC.cpp  | 50 +++++++++++++++++++++++++-----------
 src/frontend/qt_sdl/IPC.h    |  3 +++
 src/frontend/qt_sdl/main.cpp | 28 +++++++++++++++++++-
 src/frontend/qt_sdl/main.h   |  3 +++
 4 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/src/frontend/qt_sdl/IPC.cpp b/src/frontend/qt_sdl/IPC.cpp
index 05c7f82e..0ceb7b2c 100644
--- a/src/frontend/qt_sdl/IPC.cpp
+++ b/src/frontend/qt_sdl/IPC.cpp
@@ -61,6 +61,8 @@ const u32 kMaxCommandSize = 0x800;
 const u32 kCommandStart = sizeof(BufferHeader);
 const u32 kCommandEnd = kBufferSize;
 
+bool CmdRecvFlags[Cmd_MAX];
+
 
 void Init()
 {
@@ -109,6 +111,8 @@ void Init()
     }
     Buffer->unlock();
 
+    memset(CmdRecvFlags, 0, sizeof(CmdRecvFlags));
+
     printf("IPC: instance ID %d\n", InstanceID);
 }
 
@@ -185,6 +189,8 @@ void FIFOWrite(void* buf, int len)
 
 void Process()
 {
+    memset(CmdRecvFlags, 0, sizeof(CmdRecvFlags));
+
     Buffer->lock();
     u8* data = (u8*)Buffer->data();
     BufferHeader* header = (BufferHeader*)&data[0];
@@ -211,13 +217,18 @@ void Process()
         if (!(cmdheader.Recipients & (1<<InstanceID)))
             continue;
 
+        if (cmdheader.Command >= Cmd_MAX)
+            continue;
+
         // handle this command
-        switch (cmdheader.Command)
+        /*switch (cmdheader.Command)
         {
         case Cmd_Pause:
             Input::ExtHotkeyPress(HK_Pause);
             break;
-        }
+        }*/
+        CmdRecvFlags[cmdheader.Command] = true;
+        // TODO: store the command data, for future commands that will need it
     }
 
     Buffer->unlock();
@@ -225,6 +236,22 @@ void Process()
 
 bool SendCommand(u16 recipients, u16 command, u16 len, void* cmddata)
 {
+    if (command >= Cmd_MAX)
+    {
+        printf("IPC: invalid command %d\n", command);
+        return false;
+    }
+    if (len && cmddata==nullptr)
+    {
+        printf("IPC: ????? sending command with NULL buffer\n");
+        return false;
+    }
+    if (len > kMaxCommandSize)
+    {
+        printf("IPC: command too long\n");
+        return false;
+    }
+
     Buffer->lock();
     u8* data = (u8*)Buffer->data();
     BufferHeader* header = (BufferHeader*)&data[0];
@@ -237,19 +264,6 @@ bool SendCommand(u16 recipients, u16 command, u16 len, void* cmddata)
         return false;
     }
 
-    if (len && cmddata==nullptr)
-    {
-        printf("IPC: ????? sending command with NULL buffer\n");
-        Buffer->unlock();
-        return false;
-    }
-    if (len > kMaxCommandSize)
-    {
-        printf("IPC: command too long\n");
-        Buffer->unlock();
-        return false;
-    }
-
     CommandHeader cmdheader;
     cmdheader.Magic = 0x4D434C4D;
     cmdheader.SenderID = InstanceID;
@@ -264,4 +278,10 @@ bool SendCommand(u16 recipients, u16 command, u16 len, void* cmddata)
     return true;
 }
 
+bool CommandReceived(u16 command)
+{
+    if (command >= Cmd_MAX) return false;
+    return CmdRecvFlags[command];
+}
+
 }
diff --git a/src/frontend/qt_sdl/IPC.h b/src/frontend/qt_sdl/IPC.h
index 80546ec1..5016836d 100644
--- a/src/frontend/qt_sdl/IPC.h
+++ b/src/frontend/qt_sdl/IPC.h
@@ -27,6 +27,8 @@ namespace IPC
 enum
 {
     Cmd_Pause = 1,
+
+    Cmd_MAX
 };
 
 extern int InstanceID;
@@ -37,6 +39,7 @@ void DeInit();
 void Process();
 
 bool SendCommand(u16 recipients, u16 command, u16 len, void* data);
+bool CommandReceived(u16 command);
 
 }
 
diff --git a/src/frontend/qt_sdl/main.cpp b/src/frontend/qt_sdl/main.cpp
index 8436068d..10d459c6 100644
--- a/src/frontend/qt_sdl/main.cpp
+++ b/src/frontend/qt_sdl/main.cpp
@@ -198,6 +198,8 @@ EmuThread::EmuThread(QObject* parent) : QThread(parent)
     connect(this, SIGNAL(swapScreensToggle()), mainWindow->actScreenSwap, SLOT(trigger()));
     connect(this, SIGNAL(screenEmphasisToggle()), mainWindow, SLOT(onScreenEmphasisToggled()));
 
+    connect(this, SIGNAL(windowIPCPause()), mainWindow, SLOT(onIPCPause()));
+
     static_cast<ScreenPanelGL*>(mainWindow->panel)->transferLayout(this);
 }
 
@@ -359,6 +361,8 @@ void EmuThread::run()
     {
         IPC::Process();
 
+        if (IPC::CommandReceived(IPC::Cmd_Pause)) emit windowIPCPause();
+
         Input::Process();
 
         if (Input::HotkeyPressed(HK_FastForwardToggle)) emit windowLimitFPSChange();
@@ -2707,10 +2711,32 @@ void MainWindow::onPause(bool checked)
         pausedManually = false;
     }
 
-    if (Platform::InstanceID()==0) // HAX
     IPC::SendCommand(0xFFFF, IPC::Cmd_Pause, 0, nullptr);
 }
 
+void MainWindow::onIPCPause()
+{
+    // for IPC, using the normal way to trigger a pause (actPause->trigger())
+    // isn't viable, because it would lead to broadcasting more IPC 'pause' messages
+    // so we have to replicate it this way
+
+    actPause->toggle(); // changes visual state, without triggering onPause()
+    bool checked = actPause->isChecked();
+
+    if (checked)
+    {
+        emuThread->emuPause();
+        OSD::AddMessage(0, "Paused");
+        pausedManually = true;
+    }
+    else
+    {
+        emuThread->emuUnpause();
+        OSD::AddMessage(0, "Resumed");
+        pausedManually = false;
+    }
+}
+
 void MainWindow::onReset()
 {
     if (!RunningSomething) return;
diff --git a/src/frontend/qt_sdl/main.h b/src/frontend/qt_sdl/main.h
index 073a4da0..f1adaeec 100644
--- a/src/frontend/qt_sdl/main.h
+++ b/src/frontend/qt_sdl/main.h
@@ -78,6 +78,8 @@ signals:
     void windowEmuReset();
     void windowEmuFrameStep();
 
+    void windowIPCPause();
+
     void windowLimitFPSChange();
 
     void screenLayoutChange();
@@ -296,6 +298,7 @@ private slots:
     void onQuit();
 
     void onPause(bool checked);
+    void onIPCPause();
     void onReset();
     void onStop();
     void onFrameStep();