Replace balanced Core::PauseAndLock calls with RunAsCPUThread

Core::PauseAndLock requires all calls to it to be balanced, like this:

    const bool was_unpaused = Core::PauseAndLock(true);
    // do stuff on the CPU thread
    Core::PauseAndLock(false, was_unpaused);

Aside from being a bit cumbersome, it turns out all callers really
don't need to know about was_unpaused at all. They just need to do
something on the CPU thread safely, including locking/unlocking.

So this commit replaces Core::PauseAndLock with a function that
makes both the purpose and the scope of what is being run on the
CPU thread visually clear. This makes it harder to accidentally run
something on the wrong thread, or forget the second call to
PauseAndLock to unpause, or forget that it needs to be passed
was_unpaused at the end.

We also don't need comments to indicate code X is being run on the
CPU thread anymore, as the function name makes it obvious.

Source/Core/Core/Core.cpp

@@ -759,7 +759,7 @@ void RequestRefreshInfo()
   s_request_refresh_info = true;
 }
 
-bool PauseAndLock(bool do_lock, bool unpause_on_unlock)
+static bool PauseAndLock(bool do_lock, bool unpause_on_unlock)
 {
   // WARNING: PauseAndLock is not fully threadsafe so is only valid on the Host Thread
   if (!IsRunning())
@@ -806,6 +806,19 @@ bool PauseAndLock(bool do_lock, bool unpause_on_unlock)
   return was_unpaused;
 }
 
+void RunAsCPUThread(std::function<void()> function)
+{
+  const bool is_cpu_thread = IsCPUThread();
+  bool was_unpaused = false;
+  if (!is_cpu_thread)
+    was_unpaused = PauseAndLock(true, true);
+
+  function();
+
+  if (!is_cpu_thread)
+    PauseAndLock(false, was_unpaused);
+}
+
 // Display FPS info
 // This should only be called from VI
 void VideoThrottle()
@@ -955,22 +968,20 @@ void UpdateWantDeterminism(bool initial)
   {
     NOTICE_LOG(COMMON, "Want determinism <- %s", new_want_determinism ? "true" : "false");
 
-    bool was_unpaused = Core::PauseAndLock(true);
+    RunAsCPUThread([&] {
-
       s_wants_determinism = new_want_determinism;
       const auto ios = IOS::HLE::GetIOS();
       if (ios)
         ios->UpdateWantDeterminism(new_want_determinism);
       Fifo::UpdateWantDeterminism(new_want_determinism);
-    // We need to clear the cache because some parts of the JIT depend on want_determinism, e.g. use
+      // We need to clear the cache because some parts of the JIT depend on want_determinism,
-    // of FMA.
+      // e.g. use of FMA.
       JitInterface::ClearCache();
 
       // Don't call InitializeWiiRoot during boot, because IOS already does it.
       if (!initial)
         Core::InitializeWiiRoot(s_wants_determinism);
-
+    });
-    Core::PauseAndLock(false, was_unpaused);
   }
 }
 

Source/Core/Core/Core.h

@@ -74,12 +74,14 @@ void RequestRefreshInfo();
 
 void UpdateTitle();
 
-// waits until all systems are paused and fully idle, and acquires a lock on that state.
+// Run a function as the CPU thread.
-// or, if doLock is false, releases a lock on that state and optionally unpauses.
+//
-// calls must be balanced (once with doLock true, then once with doLock false) but may be recursive.
+// If called from the Host thread, the CPU thread is paused and the current thread temporarily
-// the return value of the first call should be passed in as the second argument of the second call.
+// becomes the CPU thread while running the function.
-// [NOT THREADSAFE] Host only
+// If called from the CPU thread, the function will be run directly.
-bool PauseAndLock(bool doLock, bool unpauseOnUnlock = true);
+//
+// This should only be called from the CPU thread or the host thread.
+void RunAsCPUThread(std::function<void()> function);
 
 // for calling back into UI code without introducing a dependency on it in core
 using StoppedCallbackFunc = std::function<void()>;

Source/Core/Core/HW/DVD/DVDInterface.cpp

@@ -476,12 +476,7 @@ static void InsertDiscCallback(u64 userdata, s64 cyclesLate)
 // Can only be called by the host thread
 void ChangeDiscAsHost(const std::string& new_path)
 {
-  bool was_unpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] { ChangeDiscAsCPU(new_path); });
-
-  // The host thread is now temporarily the CPU thread
-  ChangeDiscAsCPU(new_path);
-
-  Core::PauseAndLock(false, was_unpaused);
 }
 
 // Can only be called by the CPU thread

Source/Core/Core/Movie.cpp

@@ -544,8 +544,7 @@ bool BeginRecordingInput(int controllers)
   if (s_playMode != MODE_NONE || controllers == 0)
     return false;
 
-  bool was_unpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([controllers] {
-
     s_controllers = controllers;
     s_currentFrame = s_totalFrames = 0;
     s_currentLagCount = s_totalLagCount = 0;
@@ -604,8 +603,7 @@ bool BeginRecordingInput(int controllers)
 
     if (Core::IsRunning())
       Core::UpdateWantDeterminism();
-
+  });
-  Core::PauseAndLock(false, was_unpaused);
 
   Core::DisplayMessage("Starting movie recording", 2000);
   return true;

Source/Core/Core/PowerPC/BreakPoints.cpp

@@ -174,14 +174,14 @@ void MemChecks::Add(const TMemCheck& memory_check)
   if (GetMemCheck(memory_check.start_address) == nullptr)
   {
     bool had_any = HasAny();
-    bool lock = Core::PauseAndLock(true);
+    Core::RunAsCPUThread([&] {
       m_mem_checks.push_back(memory_check);
       // If this is the first one, clear the JIT cache so it can switch to
       // watchpoint-compatible code.
       if (!had_any && g_jit)
         g_jit->ClearCache();
       PowerPC::DBATUpdated();
-    Core::PauseAndLock(false, lock);
+    });
   }
 }
 
@@ -191,12 +191,12 @@ void MemChecks::Remove(u32 address)
   {
     if (i->start_address == address)
     {
-      bool lock = Core::PauseAndLock(true);
+      Core::RunAsCPUThread([&] {
         m_mem_checks.erase(i);
         if (!HasAny() && g_jit)
           g_jit->ClearCache();
         PowerPC::DBATUpdated();
-      Core::PauseAndLock(false, lock);
+      });
       return;
     }
   }

Source/Core/Core/State.cpp

@@ -207,19 +207,16 @@ void LoadFromBuffer(std::vector<u8>& buffer)
     return;
   }
 
-  bool wasUnpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] {
-
     u8* ptr = &buffer[0];
     PointerWrap p(&ptr, PointerWrap::MODE_READ);
     DoState(p);
-
+  });
-  Core::PauseAndLock(false, wasUnpaused);
 }
 
 void SaveToBuffer(std::vector<u8>& buffer)
 {
-  bool wasUnpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] {
-
     u8* ptr = nullptr;
     PointerWrap p(&ptr, PointerWrap::MODE_MEASURE);
 
@@ -230,19 +227,16 @@ void SaveToBuffer(std::vector<u8>& buffer)
     ptr = &buffer[0];
     p.SetMode(PointerWrap::MODE_WRITE);
     DoState(p);
-
+  });
-  Core::PauseAndLock(false, wasUnpaused);
 }
 
 void VerifyBuffer(std::vector<u8>& buffer)
 {
-  bool wasUnpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] {
-
     u8* ptr = &buffer[0];
     PointerWrap p(&ptr, PointerWrap::MODE_VERIFY);
     DoState(p);
-
+  });
-  Core::PauseAndLock(false, wasUnpaused);
 }
 
 // return state number not in map
@@ -399,9 +393,7 @@ static void CompressAndDumpState(CompressAndDumpState_args save_args)
 
 void SaveAs(const std::string& filename, bool wait)
 {
-  // Pause the core while we save the state
+  Core::RunAsCPUThread([&] {
-  bool wasUnpaused = Core::PauseAndLock(true);
-
     // Measure the size of the buffer.
     u8* ptr = nullptr;
     PointerWrap p(&ptr, PointerWrap::MODE_MEASURE);
@@ -438,9 +430,7 @@ void SaveAs(const std::string& filename, bool wait)
       // someone aborted the save by changing the mode?
       Core::DisplayMessage("Unable to save: Internal DoState Error", 4000);
     }
-
+  });
-  // Resume the core and disable stepping
-  Core::PauseAndLock(false, wasUnpaused);
 }
 
 bool ReadHeader(const std::string& filename, StateHeader& header)
@@ -549,9 +539,7 @@ void LoadAs(const std::string& filename)
     return;
   }
 
-  // Stop the core while we load the state
+  Core::RunAsCPUThread([&] {
-  bool wasUnpaused = Core::PauseAndLock(true);
-
     g_loadDepth++;
 
     // Save temp buffer for undo load state
@@ -612,9 +600,7 @@ void LoadAs(const std::string& filename)
       s_on_after_load_callback();
 
     g_loadDepth--;
-
+  });
-  // resume dat core
-  Core::PauseAndLock(false, wasUnpaused);
 }
 
 void SetOnAfterLoadCallback(AfterLoadCallbackFunc callback)
@@ -624,8 +610,7 @@ void SetOnAfterLoadCallback(AfterLoadCallbackFunc callback)
 
 void VerifyAt(const std::string& filename)
 {
-  bool wasUnpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] {
-
     std::vector<u8> buffer;
     LoadFileStateData(filename, buffer);
 
@@ -640,8 +625,7 @@ void VerifyAt(const std::string& filename)
       else
         Core::DisplayMessage("Unable to Verify : Can't verify state from other revisions !", 4000);
     }
-
+  });
-  Core::PauseAndLock(false, wasUnpaused);
 }
 
 void Init()

Source/Core/DolphinNoGUI/MainNoGUI.cpp

@@ -137,13 +137,13 @@ void Host_ConnectWiimote(int wm_idx, bool connect)
     const auto ios = IOS::HLE::GetIOS();
     if (!ios || SConfig::GetInstance().m_bt_passthrough_enabled)
       return;
-    bool was_unpaused = Core::PauseAndLock(true);
+    Core::RunAsCPUThread([&] {
       const auto bt = std::static_pointer_cast<IOS::HLE::Device::BluetoothEmu>(
           ios->GetDeviceByName("/dev/usb/oh1/57e/305"));
       if (bt)
         bt->AccessWiiMote(wm_idx | 0x100)->Activate(connect);
       Host_UpdateMainFrame();
-    Core::PauseAndLock(false, was_unpaused);
+    });
   });
 }
 

Source/Core/DolphinQt2/Config/Mapping/IOWindow.cpp

@@ -237,8 +237,7 @@ void IOWindow::UpdateDeviceList()
   m_block.Set(true);
   m_devices_combo->clear();
 
-  const bool paused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] {
-
     g_controller_interface.RefreshDevices();
     m_controller->UpdateReferences(g_controller_interface);
     m_controller->UpdateDefaultDevice();
@@ -255,7 +254,7 @@ void IOWindow::UpdateDeviceList()
     }
 
     m_devices_combo->setCurrentIndex(0);
+  });
 
-  Core::PauseAndLock(false, paused);
   m_block.Set(false);
 }

Source/Core/DolphinQt2/Config/Mapping/MappingWindow.cpp

@@ -229,8 +229,7 @@ void MappingWindow::RefreshDevices()
 {
   m_devices_combo->clear();
 
-  const bool paused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] {
-
     g_controller_interface.RefreshDevices();
     m_controller->UpdateReferences(g_controller_interface);
     m_controller->UpdateDefaultDevice();
@@ -246,8 +245,7 @@ void MappingWindow::RefreshDevices()
     }
 
     m_devices_combo->setCurrentIndex(0);
-
+  });
-  Core::PauseAndLock(false, paused);
 }
 
 void MappingWindow::ChangeMappingType(MappingWindow::Type type)

Source/Core/DolphinWX/Config/GCAdapterConfigDiag.cpp

@@ -71,12 +71,12 @@ void GCAdapterConfigDiag::ScheduleAdapterUpdate()
 
 void GCAdapterConfigDiag::OnUpdateAdapter(wxCommandEvent& WXUNUSED(event))
 {
-  bool unpause = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([this] {
     if (GCAdapter::IsDetected())
       m_adapter_status->SetLabelText(_("Adapter Detected"));
     else
       m_adapter_status->SetLabelText(_("Adapter Not Detected"));
-  Core::PauseAndLock(false, unpause);
+  });
 }
 
 void GCAdapterConfigDiag::OnAdapterRumble(wxCommandEvent& event)

Source/Core/DolphinWX/Frame.cpp

@@ -1249,9 +1249,7 @@ void CFrame::DoExclusiveFullscreen(bool enable_fullscreen)
   if (!g_renderer || g_renderer->IsFullscreen() == enable_fullscreen)
     return;
 
-  bool was_unpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([enable_fullscreen] { g_renderer->SetFullscreen(enable_fullscreen); });
-  g_renderer->SetFullscreen(enable_fullscreen);
-  Core::PauseAndLock(false, was_unpaused);
 }
 
 void CFrame::PollHotkeys(wxTimerEvent& event)

Source/Core/DolphinWX/FrameTools.cpp

@@ -1411,7 +1411,7 @@ void CFrame::ConnectWiimote(int wm_idx, bool connect)
   if (Core::IsRunning() && SConfig::GetInstance().bWii &&
       !SConfig::GetInstance().m_bt_passthrough_enabled)
   {
-    bool was_unpaused = Core::PauseAndLock(true);
+    Core::RunAsCPUThread([&] {
       const auto ios = IOS::HLE::GetIOS();
       if (!ios)
         return;
@@ -1423,7 +1423,7 @@ void CFrame::ConnectWiimote(int wm_idx, bool connect)
       const char* message = connect ? "Wii Remote %i connected" : "Wii Remote %i disconnected";
       Core::DisplayMessage(StringFromFormat(message, wm_idx + 1), 3000);
       Host_UpdateMainFrame();
-    Core::PauseAndLock(false, was_unpaused);
+    });
   }
 }
 
@@ -1432,13 +1432,13 @@ void CFrame::OnConnectWiimote(wxCommandEvent& event)
   const auto ios = IOS::HLE::GetIOS();
   if (!ios || SConfig::GetInstance().m_bt_passthrough_enabled)
     return;
-  bool was_unpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] {
     const auto bt = std::static_pointer_cast<IOS::HLE::Device::BluetoothEmu>(
         ios->GetDeviceByName("/dev/usb/oh1/57e/305"));
     const bool is_connected =
         bt && bt->AccessWiiMote((event.GetId() - IDM_CONNECT_WIIMOTE1) | 0x100)->IsConnected();
     ConnectWiimote(event.GetId() - IDM_CONNECT_WIIMOTE1, !is_connected);
-  Core::PauseAndLock(false, was_unpaused);
+  });
 }
 
 // Toggle fullscreen. In Windows the fullscreen mode is accomplished by expanding the m_panel to
@@ -1603,7 +1603,7 @@ void CFrame::UpdateGUI()
   GetMenuBar()->FindItem(IDM_CONNECT_BALANCEBOARD)->Enable(ShouldEnableWiimotes);
   if (ShouldEnableWiimotes)
   {
-    bool was_unpaused = Core::PauseAndLock(true);
+    Core::RunAsCPUThread([&] {
       GetMenuBar()->FindItem(IDM_CONNECT_WIIMOTE1)->Check(bt->AccessWiiMote(0x0100)->IsConnected());
       GetMenuBar()->FindItem(IDM_CONNECT_WIIMOTE2)->Check(bt->AccessWiiMote(0x0101)->IsConnected());
       GetMenuBar()->FindItem(IDM_CONNECT_WIIMOTE3)->Check(bt->AccessWiiMote(0x0102)->IsConnected());
@@ -1611,7 +1611,7 @@ void CFrame::UpdateGUI()
       GetMenuBar()
           ->FindItem(IDM_CONNECT_BALANCEBOARD)
           ->Check(bt->AccessWiiMote(0x0104)->IsConnected());
-    Core::PauseAndLock(false, was_unpaused);
+    });
   }
 
   GetMenuBar()->FindItem(IDM_RECORD_READ_ONLY)->Enable(Running || Paused);

Source/Core/DolphinWX/Input/InputConfigDiag.cpp

@@ -915,8 +915,7 @@ void InputConfigDialog::UpdateDeviceComboBox()
 
 void InputConfigDialog::RefreshDevices(wxCommandEvent&)
 {
-  bool was_unpaused = Core::PauseAndLock(true);
+  Core::RunAsCPUThread([&] {
-
     // refresh devices
     g_controller_interface.RefreshDevices();
 
@@ -932,8 +931,7 @@ void InputConfigDialog::RefreshDevices(wxCommandEvent&)
     HotkeyManagerEmu::LoadConfig();
 
     UpdateGUI();
-
+  });
-  Core::PauseAndLock(false, was_unpaused);
 }
 
 ControlGroupBox::~ControlGroupBox()