Merge pull request #8428 from jordan-woyak/better-hotkeys

InputCommon: Add hotkey support to input expressions.

12 files changed, 576 insertions, 109 deletions

diff --git a/Source/Core/Core/HW/GCPadEmu.cpp b/Source/Core/Core/HW/GCPadEmu.cpp
index 8b16173312..02e4efe4d3 100644
--- a/Source/Core/Core/HW/GCPadEmu.cpp
+++ b/Source/Core/Core/HW/GCPadEmu.cpp
@@ -187,10 +187,10 @@ void GCPad::LoadDefaults(const ControllerInterface& ciface)
   m_buttons->SetControlExpression(3, "S");  // Y
   m_buttons->SetControlExpression(4, "D");  // Z
 #ifdef _WIN32
-  m_buttons->SetControlExpression(5, "!LMENU & RETURN");  // Start
+  m_buttons->SetControlExpression(5, "RETURN");  // Start
 #else
   // OS X/Linux
-  m_buttons->SetControlExpression(5, "!`Alt_L` & Return");  // Start
+  m_buttons->SetControlExpression(5, "Return");  // Start
 #endif
 
   // stick modifiers to 50 %
diff --git a/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp b/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp
index 2702ae5b6b..549251aed1 100644
--- a/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/WiimoteEmu.cpp
@@ -603,9 +603,9 @@ void Wiimote::LoadDefaults(const ControllerInterface& ciface)
   m_buttons->SetControlExpression(5, "E");    // +
 
 #ifdef _WIN32
-  m_buttons->SetControlExpression(6, "!LMENU & RETURN");  // Home
+  m_buttons->SetControlExpression(6, "RETURN");  // Home
 #else
-  m_buttons->SetControlExpression(6, "!`Alt_L` & Return");  // Home
+  m_buttons->SetControlExpression(6, "Return");    // Home
 #endif
 
   // Shake
@@ -625,10 +625,10 @@ void Wiimote::LoadDefaults(const ControllerInterface& ciface)
   m_dpad->SetControlExpression(2, "LEFT");   // Left
   m_dpad->SetControlExpression(3, "RIGHT");  // Right
 #elif __APPLE__
-  m_dpad->SetControlExpression(0, "Up Arrow");              // Up
-  m_dpad->SetControlExpression(1, "Down Arrow");            // Down
-  m_dpad->SetControlExpression(2, "Left Arrow");            // Left
-  m_dpad->SetControlExpression(3, "Right Arrow");           // Right
+  m_dpad->SetControlExpression(0, "Up Arrow");     // Up
+  m_dpad->SetControlExpression(1, "Down Arrow");   // Down
+  m_dpad->SetControlExpression(2, "Left Arrow");   // Left
+  m_dpad->SetControlExpression(3, "Right Arrow");  // Right
 #else
   m_dpad->SetControlExpression(0, "Up");     // Up
   m_dpad->SetControlExpression(1, "Down");   // Down
diff --git a/Source/Core/Core/HotkeyManager.cpp b/Source/Core/Core/HotkeyManager.cpp
index 235b6f739d..656542032d 100644
--- a/Source/Core/Core/HotkeyManager.cpp
+++ b/Source/Core/Core/HotkeyManager.cpp
@@ -409,83 +409,72 @@ void HotkeyManager::LoadDefaults(const ControllerInterface& ciface)
 {
   EmulatedController::LoadDefaults(ciface);
 
-#ifdef _WIN32
-  const std::string NON = "(!(LMENU | RMENU) & !(LSHIFT | RSHIFT) & !(LCONTROL | RCONTROL))";
-  const std::string ALT = "((LMENU | RMENU) & !(LSHIFT | RSHIFT) & !(LCONTROL | RCONTROL))";
-  const std::string SHIFT = "(!(LMENU | RMENU) & (LSHIFT | RSHIFT) & !(LCONTROL | RCONTROL))";
-  const std::string CTRL = "(!(LMENU | RMENU) & !(LSHIFT | RSHIFT) & (LCONTROL | RCONTROL))";
-#elif __APPLE__
-  const std::string NON =
-      "(!`Left Alt` & !(`Left Shift`| `Right Shift`) & !(`Left Control` | `Right Control`))";
-  const std::string ALT =
-      "(`Left Alt` & !(`Left Shift`| `Right Shift`) & !(`Left Control` | `Right Control`))";
-  const std::string SHIFT =
-      "(!`Left Alt` & (`Left Shift`| `Right Shift`) & !(`Left Control` | `Right Control`))";
-  const std::string CTRL =
-      "(!`Left Alt` & !(`Left Shift`| `Right Shift`) & (`Left Control` | `Right Control`))";
-#else
-  const std::string NON = "(!`Alt_L` & !(`Shift_L` | `Shift_R`) & !(`Control_L` | `Control_R` ))";
-  const std::string ALT = "(`Alt_L` & !(`Shift_L` | `Shift_R`) & !(`Control_L` | `Control_R` ))";
-  const std::string SHIFT = "(!`Alt_L` & (`Shift_L` | `Shift_R`) & !(`Control_L` | `Control_R` ))";
-  const std::string CTRL = "(!`Alt_L` & !(`Shift_L` | `Shift_R`) & (`Control_L` | `Control_R` ))";
-#endif
-
   auto set_key_expression = [this](int index, const std::string& expression) {
     m_keys[FindGroupByID(index)]
         ->controls[GetIndexForGroup(FindGroupByID(index), index)]
         ->control_ref->SetExpression(expression);
   };
 
+  auto hotkey_string = [](std::vector<std::string_view> inputs) {
+    std::string result;
+    for (auto& input : inputs)
+    {
+      if (!result.empty())
+        result += '+';
+      result += input;
+    }
+    return "@(" + result + ')';
+  };
+
   // General hotkeys
-  set_key_expression(HK_OPEN, CTRL + " & O");
-  set_key_expression(HK_PLAY_PAUSE, NON + " & `F10`");
+  set_key_expression(HK_OPEN, hotkey_string({"Ctrl", "O"}));
+  set_key_expression(HK_PLAY_PAUSE, "F10");
 #ifdef _WIN32
-  set_key_expression(HK_STOP, NON + " & ESCAPE");
-  set_key_expression(HK_FULLSCREEN, ALT + " & RETURN");
+  set_key_expression(HK_STOP, "ESCAPE");
+  set_key_expression(HK_FULLSCREEN, hotkey_string({"Alt", "RETURN"}));
 #else
-  set_key_expression(HK_STOP, NON + " & Escape");
-  set_key_expression(HK_FULLSCREEN, ALT + " & Return");
+  set_key_expression(HK_STOP, "Escape");
+  set_key_expression(HK_FULLSCREEN, hotkey_string({"Alt", "Return"}));
 #endif
-  set_key_expression(HK_STEP, NON + " & `F11`");
-  set_key_expression(HK_STEP_OVER, SHIFT + " & `F10`");
-  set_key_expression(HK_STEP_OUT, SHIFT + " & `F11`");
-  set_key_expression(HK_BP_TOGGLE, SHIFT + " & `F9`");
-  set_key_expression(HK_SCREENSHOT, NON + " & `F9`");
-  set_key_expression(HK_WIIMOTE1_CONNECT, ALT + " & `F5`");
-  set_key_expression(HK_WIIMOTE2_CONNECT, ALT + " & `F6`");
-  set_key_expression(HK_WIIMOTE3_CONNECT, ALT + " & `F7`");
-  set_key_expression(HK_WIIMOTE4_CONNECT, ALT + " & `F8`");
-  set_key_expression(HK_BALANCEBOARD_CONNECT, ALT + " & `F9`");
+  set_key_expression(HK_STEP, "F11");
+  set_key_expression(HK_STEP_OVER, hotkey_string({"Shift", "F10"}));
+  set_key_expression(HK_STEP_OUT, hotkey_string({"Shift", "F11"}));
+  set_key_expression(HK_BP_TOGGLE, hotkey_string({"Shift", "F9"}));
+  set_key_expression(HK_SCREENSHOT, "F9");
+  set_key_expression(HK_WIIMOTE1_CONNECT, hotkey_string({"Alt", "F5"}));
+  set_key_expression(HK_WIIMOTE2_CONNECT, hotkey_string({"Alt", "F6"}));
+  set_key_expression(HK_WIIMOTE3_CONNECT, hotkey_string({"Alt", "F7"}));
+  set_key_expression(HK_WIIMOTE4_CONNECT, hotkey_string({"Alt", "F8"}));
+  set_key_expression(HK_BALANCEBOARD_CONNECT, hotkey_string({"Alt", "F9"}));
 #ifdef _WIN32
-  set_key_expression(HK_TOGGLE_THROTTLE, NON + " & TAB");
+  set_key_expression(HK_TOGGLE_THROTTLE, "TAB");
 #else
-  set_key_expression(HK_TOGGLE_THROTTLE, NON + " & Tab");
+  set_key_expression(HK_TOGGLE_THROTTLE, "Tab");
 #endif
 
   // Freelook
-  set_key_expression(HK_FREELOOK_DECREASE_SPEED, SHIFT + " & `1`");
-  set_key_expression(HK_FREELOOK_INCREASE_SPEED, SHIFT + " & `2`");
-  set_key_expression(HK_FREELOOK_RESET_SPEED, SHIFT + " & F");
-  set_key_expression(HK_FREELOOK_UP, SHIFT + " & E");
-  set_key_expression(HK_FREELOOK_DOWN, SHIFT + " & Q");
-  set_key_expression(HK_FREELOOK_LEFT, SHIFT + " & A");
-  set_key_expression(HK_FREELOOK_RIGHT, SHIFT + " & D");
-  set_key_expression(HK_FREELOOK_ZOOM_IN, SHIFT + " & W");
-  set_key_expression(HK_FREELOOK_ZOOM_OUT, SHIFT + " & S");
-  set_key_expression(HK_FREELOOK_RESET, SHIFT + " & R");
-  set_key_expression(HK_FREELOOK_INCREASE_FOV_X, SHIFT + " & `Axis Z+`");
-  set_key_expression(HK_FREELOOK_DECREASE_FOV_X, SHIFT + " & `Axis Z-`");
-  set_key_expression(HK_FREELOOK_INCREASE_FOV_Y, SHIFT + " & `Axis Z+`");
-  set_key_expression(HK_FREELOOK_DECREASE_FOV_Y, SHIFT + " & `Axis Z-`");
+  set_key_expression(HK_FREELOOK_DECREASE_SPEED, hotkey_string({"Shift", "1"}));
+  set_key_expression(HK_FREELOOK_INCREASE_SPEED, hotkey_string({"Shift", "2"}));
+  set_key_expression(HK_FREELOOK_RESET_SPEED, hotkey_string({"Shift", "F"}));
+  set_key_expression(HK_FREELOOK_UP, hotkey_string({"Shift", "E"}));
+  set_key_expression(HK_FREELOOK_DOWN, hotkey_string({"Shift", "Q"}));
+  set_key_expression(HK_FREELOOK_LEFT, hotkey_string({"Shift", "A"}));
+  set_key_expression(HK_FREELOOK_RIGHT, hotkey_string({"Shift", "D"}));
+  set_key_expression(HK_FREELOOK_ZOOM_IN, hotkey_string({"Shift", "W"}));
+  set_key_expression(HK_FREELOOK_ZOOM_OUT, hotkey_string({"Shift", "S"}));
+  set_key_expression(HK_FREELOOK_RESET, hotkey_string({"Shift", "R"}));
+  set_key_expression(HK_FREELOOK_INCREASE_FOV_X, hotkey_string({"Shift", "`Axis Z+`"}));
+  set_key_expression(HK_FREELOOK_DECREASE_FOV_X, hotkey_string({"Shift", "`Axis Z-`"}));
+  set_key_expression(HK_FREELOOK_INCREASE_FOV_Y, hotkey_string({"Shift", "`Axis Z+`"}));
+  set_key_expression(HK_FREELOOK_DECREASE_FOV_Y, hotkey_string({"Shift", "`Axis Z-`"}));
 
   // Savestates
-  const std::string non_fmt = NON + " & `F{}`";
-  const std::string shift_fmt = SHIFT + " & `F{}`";
   for (int i = 0; i < 8; i++)
   {
-    set_key_expression(HK_LOAD_STATE_SLOT_1 + i, fmt::format(non_fmt, i + 1));
-    set_key_expression(HK_SAVE_STATE_SLOT_1 + i, fmt::format(shift_fmt, i + 1));
+    set_key_expression(HK_LOAD_STATE_SLOT_1 + i, fmt::format("F%d", i + 1));
+    set_key_expression(HK_SAVE_STATE_SLOT_1 + i,
+                       hotkey_string({"Shift", fmt::format("F%d", i + 1)}));
   }
-  set_key_expression(HK_UNDO_LOAD_STATE, NON + " & `F12`");
-  set_key_expression(HK_UNDO_SAVE_STATE, SHIFT + " & `F12`");
+  set_key_expression(HK_UNDO_LOAD_STATE, "F12");
+  set_key_expression(HK_UNDO_SAVE_STATE, hotkey_string({"Shift", "F12"}));
 }
diff --git a/Source/Core/DolphinQt/Config/Mapping/MappingCommon.cpp b/Source/Core/DolphinQt/Config/Mapping/MappingCommon.cpp
index bbd15ad831..eb61963300 100644
--- a/Source/Core/DolphinQt/Config/Mapping/MappingCommon.cpp
+++ b/Source/Core/DolphinQt/Config/Mapping/MappingCommon.cpp
@@ -5,6 +5,7 @@
 #include "DolphinQt/Config/Mapping/MappingCommon.h"
 
 #include <tuple>
+#include <vector>
 
 #include <QApplication>
 #include <QPushButton>
@@ -14,14 +15,23 @@
 
 #include "DolphinQt/QtUtils/BlockUserInputFilter.h"
 #include "InputCommon/ControlReference/ControlReference.h"
-#include "InputCommon/ControllerInterface/Device.h"
 
 #include "Common/Thread.h"
 
 namespace MappingCommon
 {
-constexpr int INPUT_DETECT_TIME = 3000;
-constexpr int OUTPUT_TEST_TIME = 2000;
+constexpr auto INPUT_DETECT_INITIAL_TIME = std::chrono::seconds(3);
+constexpr auto INPUT_DETECT_CONFIRMATION_TIME = std::chrono::milliseconds(500);
+constexpr auto INPUT_DETECT_MAXIMUM_TIME = std::chrono::seconds(5);
+
+constexpr auto OUTPUT_TEST_TIME = std::chrono::seconds(2);
+
+// Pressing inputs at the same time will result in the & operator vs a hotkey expression.
+constexpr auto HOTKEY_VS_CONJUNCION_THRESHOLD = std::chrono::milliseconds(50);
+
+// Some devices (e.g. DS4) provide an analog and digital input for the trigger.
+// We prefer just the analog input for simultaneous digital+analog input detections.
+constexpr auto SPURIOUS_TRIGGER_COMBO_THRESHOLD = std::chrono::milliseconds(150);
 
 QString GetExpressionForControl(const QString& control_name,
                                 const ciface::Core::DeviceQualifier& control_device,
@@ -68,7 +78,11 @@ QString DetectExpression(QPushButton* button, ciface::Core::DeviceContainer& dev
   // Avoid that the button press itself is registered as an event
   Common::SleepCurrentThread(50);
 
-  const auto [device, input] = device_container.DetectInput(INPUT_DETECT_TIME, device_strings);
+  auto detections =
+      device_container.DetectInput(device_strings, INPUT_DETECT_INITIAL_TIME,
+                                   INPUT_DETECT_CONFIRMATION_TIME, INPUT_DETECT_MAXIMUM_TIME);
+
+  RemoveSpuriousTriggerCombinations(&detections);
 
   const auto timer = new QTimer(button);
 
@@ -83,14 +97,7 @@ QString DetectExpression(QPushButton* button, ciface::Core::DeviceContainer& dev
 
   button->setText(old_text);
 
-  if (!input)
-    return {};
-
-  ciface::Core::DeviceQualifier device_qualifier;
-  device_qualifier.FromDevice(device.get());
-
-  return MappingCommon::GetExpressionForControl(QString::fromStdString(input->GetName()),
-                                                device_qualifier, default_device, quote);
+  return BuildExpression(detections, default_device, quote);
 }
 
 void TestOutput(QPushButton* button, OutputReference* reference)
@@ -102,10 +109,103 @@ void TestOutput(QPushButton* button, OutputReference* reference)
   QApplication::processEvents();
 
   reference->State(1.0);
-  Common::SleepCurrentThread(OUTPUT_TEST_TIME);
+  std::this_thread::sleep_for(OUTPUT_TEST_TIME);
   reference->State(0.0);
 
   button->setText(old_text);
 }
 
+void RemoveSpuriousTriggerCombinations(
+    std::vector<ciface::Core::DeviceContainer::InputDetection>* detections)
+{
+  const auto is_spurious = [&](auto& detection) {
+    return std::any_of(detections->begin(), detections->end(), [&](auto& d) {
+      // This is a suprious digital detection if a "smooth" (analog) detection is temporally near.
+      return &d != &detection && d.smoothness > 1 &&
+             abs(d.press_time - detection.press_time) < SPURIOUS_TRIGGER_COMBO_THRESHOLD;
+    });
+  };
+
+  detections->erase(std::remove_if(detections->begin(), detections->end(), is_spurious),
+                    detections->end());
+}
+
+QString
+BuildExpression(const std::vector<ciface::Core::DeviceContainer::InputDetection>& detections,
+                const ciface::Core::DeviceQualifier& default_device, Quote quote)
+{
+  std::vector<const ciface::Core::DeviceContainer::InputDetection*> pressed_inputs;
+
+  QStringList alternations;
+
+  const auto get_control_expression = [&](auto& detection) {
+    // Return the parent-most name if there is one for better hotkey strings.
+    // Detection of L/R_Ctrl will be changed to just Ctrl.
+    // Users can manually map L_Ctrl if they so desire.
+    const auto input = (quote == Quote::On) ?
+                           detection.device->GetParentMostInput(detection.input) :
+                           detection.input;
+
+    ciface::Core::DeviceQualifier device_qualifier;
+    device_qualifier.FromDevice(detection.device.get());
+
+    return MappingCommon::GetExpressionForControl(QString::fromStdString(input->GetName()),
+                                                  device_qualifier, default_device, quote);
+  };
+
+  bool new_alternation = false;
+
+  const auto handle_press = [&](auto& detection) {
+    pressed_inputs.emplace_back(&detection);
+    new_alternation = true;
+  };
+
+  const auto handle_release = [&]() {
+    if (!new_alternation)
+      return;
+
+    new_alternation = false;
+
+    QStringList alternation;
+    for (auto* input : pressed_inputs)
+      alternation.push_back(get_control_expression(*input));
+
+    const bool is_hotkey = pressed_inputs.size() >= 2 &&
+                           (pressed_inputs[1]->press_time - pressed_inputs[0]->press_time) >
+                               HOTKEY_VS_CONJUNCION_THRESHOLD;
+
+    if (is_hotkey)
+    {
+      alternations.push_back(QStringLiteral("@(%1)").arg(alternation.join(QLatin1Char('+'))));
+    }
+    else
+    {
+      alternation.sort();
+      alternations.push_back(alternation.join(QLatin1Char('&')));
+    }
+  };
+
+  for (auto& detection : detections)
+  {
+    // Remove since released inputs.
+    for (auto it = pressed_inputs.begin(); it != pressed_inputs.end();)
+    {
+      if (!((*it)->release_time > detection.press_time))
+      {
+        handle_release();
+        it = pressed_inputs.erase(it);
+      }
+      else
+        ++it;
+    }
+
+    handle_press(detection);
+  }
+
+  handle_release();
+
+  alternations.removeDuplicates();
+  return alternations.join(QLatin1Char('|'));
+}
+
 }  // namespace MappingCommon
diff --git a/Source/Core/DolphinQt/Config/Mapping/MappingCommon.h b/Source/Core/DolphinQt/Config/Mapping/MappingCommon.h
index f3372bdb27..27a3cf7041 100644
--- a/Source/Core/DolphinQt/Config/Mapping/MappingCommon.h
+++ b/Source/Core/DolphinQt/Config/Mapping/MappingCommon.h
@@ -7,16 +7,12 @@
 #include <string>
 #include <vector>
 
+#include "InputCommon/ControllerInterface/Device.h"
+
 class QString;
 class OutputReference;
 class QPushButton;
 
-namespace ciface::Core
-{
-class DeviceContainer;
-class DeviceQualifier;
-}  // namespace ciface::Core
-
 namespace MappingCommon
 {
 enum class Quote
@@ -37,4 +33,9 @@ QString DetectExpression(QPushButton* button, ciface::Core::DeviceContainer& dev
 
 void TestOutput(QPushButton* button, OutputReference* reference);
 
+void RemoveSpuriousTriggerCombinations(std::vector<ciface::Core::DeviceContainer::InputDetection>*);
+
+QString BuildExpression(const std::vector<ciface::Core::DeviceContainer::InputDetection>&,
+                        const ciface::Core::DeviceQualifier& default_device, Quote quote);
+
 }  // namespace MappingCommon
diff --git a/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp b/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
index 1b1a24753c..d4f93450e3 100644
--- a/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
+++ b/Source/Core/InputCommon/ControlReference/ExpressionParser.cpp
@@ -2,9 +2,11 @@
 // Licensed under GPLv2+
 // Refer to the license.txt file included.
 
+#include <algorithm>
 #include <cassert>
 #include <cmath>
 #include <iostream>
+#include <map>
 #include <memory>
 #include <regex>
 #include <string>
@@ -21,6 +23,55 @@ namespace ciface::ExpressionParser
 {
 using namespace ciface::Core;
 
+class ControlExpression;
+
+class HotkeySuppressions
+{
+public:
+  using Modifiers = std::vector<std::unique_ptr<ControlExpression>>;
+
+  struct InvokingDeleter
+  {
+    template <typename T>
+    void operator()(T* func)
+    {
+      (*func)();
+    }
+  };
+
+  using Suppressor = std::unique_ptr<std::function<void()>, InvokingDeleter>;
+
+  bool IsSuppressed(Device::Input* input) const
+  {
+    // Input is suppressed if it exists in the map at all.
+    return m_suppressions.lower_bound({input, nullptr}) !=
+           m_suppressions.lower_bound({input + 1, nullptr});
+  }
+
+  bool IsSuppressedIgnoringModifiers(Device::Input* input, const Modifiers& ignore_modifiers) const;
+
+  // Suppresses each input + modifier pair.
+  // The returned object removes the suppression on destruction.
+  Suppressor MakeSuppressor(const Modifiers* modifiers,
+                            const std::unique_ptr<ControlExpression>* final_input);
+
+private:
+  using Suppression = std::pair<Device::Input*, Device::Input*>;
+  using SuppressionLevel = u16;
+
+  void RemoveSuppression(Device::Input* modifier, Device::Input* final_input)
+  {
+    auto it = m_suppressions.find({final_input, modifier});
+    if ((--it->second) == 0)
+      m_suppressions.erase(it);
+  }
+
+  // Holds counts of suppressions for each input/modifier pair.
+  std::map<Suppression, SuppressionLevel> m_suppressions;
+};
+
+static HotkeySuppressions s_hotkey_suppressions;
+
 Token::Token(TokenType type_) : type(type_)
 {
 }
@@ -112,6 +163,8 @@ Token Lexer::NextToken()
     return Token(TOK_LPAREN);
   case ')':
     return Token(TOK_RPAREN);
+  case '@':
+    return Token(TOK_HOTKEY);
   case '&':
     return Token(TOK_AND);
   case '|':
@@ -196,8 +249,17 @@ public:
   std::shared_ptr<Device> m_device;
 
   explicit ControlExpression(ControlQualifier qualifier_) : qualifier(qualifier_) {}
+
   ControlState GetValue() const override
   {
+    if (s_hotkey_suppressions.IsSuppressed(input))
+      return 0;
+    else
+      return GetValueIgnoringSuppression();
+  }
+
+  ControlState GetValueIgnoringSuppression() const
+  {
     if (!input)
       return 0.0;
 
@@ -222,12 +284,46 @@ public:
     output = env.FindOutput(qualifier);
   }
 
+  Device::Input* GetInput() const { return input; };
+
 private:
   ControlQualifier qualifier;
   Device::Input* input = nullptr;
   Device::Output* output = nullptr;
 };
 
+bool HotkeySuppressions::IsSuppressedIgnoringModifiers(Device::Input* input,
+                                                       const Modifiers& ignore_modifiers) const
+{
+  // Input is suppressed if it exists in the map with a modifier that we aren't ignoring.
+  auto it = m_suppressions.lower_bound({input, nullptr});
+  auto it_end = m_suppressions.lower_bound({input + 1, nullptr});
+
+  // We need to ignore L_Ctrl R_Ctrl when supplied Ctrl and vice-versa.
+  const auto is_same_modifier = [](Device::Input* i1, Device::Input* i2) {
+    return i1 == i2 || i1->IsChild(i2) || i2->IsChild(i1);
+  };
+
+  return std::any_of(it, it_end, [&](auto& s) {
+    return std::none_of(begin(ignore_modifiers), end(ignore_modifiers),
+                        [&](auto& m) { return is_same_modifier(m->GetInput(), s.first.second); });
+  });
+}
+
+HotkeySuppressions::Suppressor
+HotkeySuppressions::MakeSuppressor(const Modifiers* modifiers,
+                                   const std::unique_ptr<ControlExpression>* final_input)
+{
+  for (auto& modifier : *modifiers)
+    ++m_suppressions[{(*final_input)->GetInput(), modifier->GetInput()}];
+
+  return Suppressor(std::make_unique<std::function<void()>>([this, modifiers, final_input]() {
+                      for (auto& modifier : *modifiers)
+                        RemoveSuppression(modifier->GetInput(), (*final_input)->GetInput());
+                    }).release(),
+                    InvokingDeleter{});
+}
+
 class BinaryExpression : public Expression
 {
 public:
@@ -374,6 +470,90 @@ protected:
   ControlState* m_value_ptr{};
 };
 
+class HotkeyExpression : public Expression
+{
+public:
+  HotkeyExpression(std::vector<std::unique_ptr<ControlExpression>> inputs)
+      : m_modifiers(std::move(inputs))
+  {
+    m_final_input = std::move(m_modifiers.back());
+    m_modifiers.pop_back();
+  }
+
+  ControlState GetValue() const override
+  {
+    const bool modifiers_pressed = std::all_of(m_modifiers.begin(), m_modifiers.end(),
+                                               [](const std::unique_ptr<ControlExpression>& input) {
+                                                 return input->GetValue() > CONDITION_THRESHOLD;
+                                               });
+
+    const auto final_input_state = m_final_input->GetValueIgnoringSuppression();
+
+    if (modifiers_pressed)
+    {
+      // Ignore suppression of our own modifiers. This also allows superset modifiers to function.
+      const bool is_suppressed = s_hotkey_suppressions.IsSuppressedIgnoringModifiers(
+          m_final_input->GetInput(), m_modifiers);
+
+      if (final_input_state < CONDITION_THRESHOLD)
+        m_is_blocked = false;
+
+      // If some other hotkey suppressed us, require a release of final input to be ready again.
+      if (is_suppressed)
+        m_is_blocked = true;
+
+      if (m_is_blocked)
+        return 0;
+
+      EnableSuppression();
+
+      // Our modifiers are active. Pass through the final input.
+      return final_input_state;
+    }
+    else
+    {
+      m_suppressor = {};
+      m_is_blocked = final_input_state > CONDITION_THRESHOLD;
+    }
+
+    return 0;
+  }
+
+  void SetValue(ControlState) override {}
+
+  int CountNumControls() const override
+  {
+    int result = 0;
+    for (auto& input : m_modifiers)
+      result += input->CountNumControls();
+    return result + m_final_input->CountNumControls();
+  }
+
+  void UpdateReferences(ControlEnvironment& env) override
+  {
+    for (auto& input : m_modifiers)
+      input->UpdateReferences(env);
+
+    m_final_input->UpdateReferences(env);
+
+    // We must update our suppression with valid pointers.
+    if (m_suppressor)
+      EnableSuppression();
+  }
+
+private:
+  void EnableSuppression() const
+  {
+    if (!m_suppressor)
+      m_suppressor = s_hotkey_suppressions.MakeSuppressor(&m_modifiers, &m_final_input);
+  }
+
+  HotkeySuppressions::Modifiers m_modifiers;
+  std::unique_ptr<ControlExpression> m_final_input;
+  mutable HotkeySuppressions::Suppressor m_suppressor;
+  mutable bool m_is_blocked = false;
+};
+
 // This class proxies all methods to its either left-hand child if it has bound controls, or its
 // right-hand child. Its intended use is for supporting old-style barewords expressions.
 class CoalesceExpression : public Expression
@@ -600,6 +780,10 @@ private:
     {
       return ParseParens();
     }
+    case TOK_HOTKEY:
+    {
+      return ParseHotkeys();
+    }
     case TOK_SUB:
     {
       // An atom was expected but we got a subtraction symbol.
@@ -684,6 +868,39 @@ private:
     return result;
   }
 
+  ParseResult ParseHotkeys()
+  {
+    Token tok = Chew();
+    if (tok.type != TOK_LPAREN)
+      return ParseResult::MakeErrorResult(tok, _trans("Expected opening paren."));
+
+    std::vector<std::unique_ptr<ControlExpression>> inputs;
+
+    while (true)
+    {
+      tok = Chew();
+
+      if (tok.type != TOK_CONTROL && tok.type != TOK_BAREWORD)
+        return ParseResult::MakeErrorResult(tok, _trans("Expected name of input."));
+
+      ControlQualifier cq;
+      cq.FromString(tok.data);
+      inputs.emplace_back(std::make_unique<ControlExpression>(std::move(cq)));
+
+      tok = Chew();
+
+      if (tok.type == TOK_ADD)
+        continue;
+
+      if (tok.type == TOK_RPAREN)
+        break;
+
+      return ParseResult::MakeErrorResult(tok, _trans("Expected + or closing paren."));
+    }
+
+    return ParseResult::MakeSuccessfulResult(std::make_unique<HotkeyExpression>(std::move(inputs)));
+  }
+
   ParseResult ParseToplevel() { return ParseBinary(); }
 };  // namespace ExpressionParser
 
diff --git a/Source/Core/InputCommon/ControlReference/ExpressionParser.h b/Source/Core/InputCommon/ControlReference/ExpressionParser.h
index c0d807bf17..a879528d4b 100644
--- a/Source/Core/InputCommon/ControlReference/ExpressionParser.h
+++ b/Source/Core/InputCommon/ControlReference/ExpressionParser.h
@@ -26,6 +26,7 @@ enum TokenType
   TOK_VARIABLE,
   TOK_BAREWORD,
   TOK_COMMENT,
+  TOK_HOTKEY,
   // Binary Ops:
   TOK_BINARY_OPS_BEGIN,
   TOK_AND = TOK_BINARY_OPS_BEGIN,
diff --git a/Source/Core/InputCommon/ControllerInterface/DInput/DInputKeyboardMouse.cpp b/Source/Core/InputCommon/ControllerInterface/DInput/DInputKeyboardMouse.cpp
index 1e617d6c24..5aca9f5280 100644
--- a/Source/Core/InputCommon/ControllerInterface/DInput/DInputKeyboardMouse.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/DInput/DInputKeyboardMouse.cpp
@@ -87,6 +87,11 @@ KeyboardMouse::KeyboardMouse(const LPDIRECTINPUTDEVICE8 kb_device,
   for (u8 i = 0; i < sizeof(named_keys) / sizeof(*named_keys); ++i)
     AddInput(new Key(i, m_state_in.keyboard[named_keys[i].code]));
 
+  // Add combined left/right modifiers with consistent naming across platforms.
+  AddCombinedInput("Alt", {"LMENU", "RMENU"});
+  AddCombinedInput("Shift", {"LSHIFT", "RSHIFT"});
+  AddCombinedInput("Ctrl", {"LCONTROL", "RCONTROL"});
+
   // MOUSE
   DIDEVCAPS mouse_caps = {};
   mouse_caps.dwSize = sizeof(mouse_caps);
diff --git a/Source/Core/InputCommon/ControllerInterface/Device.cpp b/Source/Core/InputCommon/ControllerInterface/Device.cpp
index ebed1ad421..2fd7fb02e7 100644
--- a/Source/Core/InputCommon/ControllerInterface/Device.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/Device.cpp
@@ -13,13 +13,47 @@
 
 #include <fmt/format.h>
 
+#include "Common/MathUtil.h"
 #include "Common/Thread.h"
 
 namespace ciface::Core
 {
 // Compared to an input's current state (ideally 1.0) minus abs(initial_state) (ideally 0.0).
+// Note: Detect() logic assumes this is greater than 0.5.
 constexpr ControlState INPUT_DETECT_THRESHOLD = 0.55;
 
+class CombinedInput final : public Device::Input
+{
+public:
+  using Inputs = std::pair<Device::Input*, Device::Input*>;
+
+  CombinedInput(std::string name, const Inputs& inputs) : m_name(std::move(name)), m_inputs(inputs)
+  {
+  }
+  ControlState GetState() const override
+  {
+    ControlState result = 0;
+
+    if (m_inputs.first)
+      result = m_inputs.first->GetState();
+
+    if (m_inputs.second)
+      result = std::max(result, m_inputs.second->GetState());
+
+    return result;
+  }
+  std::string GetName() const override { return m_name; }
+  bool IsDetectable() const override { return false; }
+  bool IsChild(const Input* input) const override
+  {
+    return m_inputs.first == input || m_inputs.second == input;
+  }
+
+private:
+  const std::string m_name;
+  const std::pair<Device::Input*, Device::Input*> m_inputs;
+};
+
 Device::~Device()
 {
   // delete inputs
@@ -51,6 +85,20 @@ std::string Device::GetQualifiedName() const
   return fmt::format("{}/{}/{}", GetSource(), GetId(), GetName());
 }
 
+auto Device::GetParentMostInput(Input* child) const -> Input*
+{
+  for (auto* input : m_inputs)
+  {
+    if (input->IsChild(child))
+    {
+      // Running recursively is currently unnecessary but it doesn't hurt.
+      return GetParentMostInput(input);
+    }
+  }
+
+  return child;
+}
+
 Device::Input* Device::FindInput(std::string_view name) const
 {
   for (Input* input : m_inputs)
@@ -102,6 +150,11 @@ bool Device::FullAnalogSurface::IsMatchingName(std::string_view name) const
   return old_name == name;
 }
 
+void Device::AddCombinedInput(std::string name, const std::pair<std::string, std::string>& inputs)
+{
+  AddInput(new CombinedInput(std::move(name), {FindInput(inputs.first), FindInput(inputs.second)}));
+}
+
 //
 // DeviceQualifier :: ToString
 //
@@ -249,18 +302,54 @@ bool DeviceContainer::HasConnectedDevice(const DeviceQualifier& qualifier) const
   return device != nullptr && device->IsValid();
 }
 
-// Wait for input on a particular device.
-// Inputs are considered if they are first seen in a neutral state.
+// Wait for inputs on supplied devices.
+// Inputs are only considered if they are first seen in a neutral state.
 // This is useful for crazy flightsticks that have certain buttons that are always held down
 // and also properly handles detection when using "FullAnalogSurface" inputs.
-// Upon input, return the detected Device and Input, else return nullptrs
-std::pair<std::shared_ptr<Device>, Device::Input*>
-DeviceContainer::DetectInput(u32 wait_ms, const std::vector<std::string>& device_strings) const
+// Multiple detections are returned until the various timeouts have been reached.
+auto DeviceContainer::DetectInput(const std::vector<std::string>& device_strings,
+                                  std::chrono::milliseconds initial_wait,
+                                  std::chrono::milliseconds confirmation_wait,
+                                  std::chrono::milliseconds maximum_wait) const
+    -> std::vector<InputDetection>
 {
   struct InputState
   {
-    ciface::Core::Device::Input& input;
-    ControlState initial_state;
+    InputState(ciface::Core::Device::Input* input_) : input{input_} { stats.Push(0.0); }
+
+    ciface::Core::Device::Input* input;
+    ControlState initial_state = input->GetState();
+    ControlState last_state = initial_state;
+    MathUtil::RunningVariance<ControlState> stats;
+
+    // Prevent multiiple detections until after release.
+    bool is_ready = true;
+
+    void Update()
+    {
+      const auto new_state = input->GetState();
+
+      if (!is_ready && new_state < (1 - INPUT_DETECT_THRESHOLD))
+      {
+        last_state = new_state;
+        is_ready = true;
+        stats.Clear();
+      }
+
+      const auto difference = new_state - last_state;
+      stats.Push(difference);
+      last_state = new_state;
+    }
+
+    bool IsPressed()
+    {
+      if (!is_ready)
+        return false;
+
+      // We want an input that was initially 0.0 and currently 1.0.
+      const auto detection_score = (last_state - std::abs(initial_state));
+      return detection_score > INPUT_DETECT_THRESHOLD;
+    }
   };
 
   struct DeviceState
@@ -285,13 +374,13 @@ DeviceContainer::DetectInput(u32 wait_ms, const std::vector<std::string>& device
 
     for (auto* input : device->Inputs())
     {
-      // Don't detect things like absolute cursor position.
+      // Don't detect things like absolute cursor positions, accelerometers, or gyroscopes.
       if (!input->IsDetectable())
         continue;
 
       // Undesirable axes will have negative values here when trying to map a
       // "FullAnalogSurface".
-      input_states.push_back({*input, input->GetState()});
+      input_states.push_back(InputState{input});
     }
 
     if (!input_states.empty())
@@ -301,27 +390,59 @@ DeviceContainer::DetectInput(u32 wait_ms, const std::vector<std::string>& device
   if (device_states.empty())
     return {};
 
-  u32 time = 0;
-  while (time < wait_ms)
+  std::vector<InputDetection> detections;
+
+  const auto start_time = Clock::now();
+  while (true)
   {
+    const auto now = Clock::now();
+    const auto elapsed_time = now - start_time;
+
+    if (elapsed_time >= maximum_wait || (detections.empty() && elapsed_time >= initial_wait) ||
+        (!detections.empty() && detections.back().release_time.has_value() &&
+         now >= *detections.back().release_time + confirmation_wait))
+    {
+      break;
+    }
+
     Common::SleepCurrentThread(10);
-    time += 10;
 
     for (auto& device_state : device_states)
     {
-      for (auto& input_state : device_state.input_states)
+      for (std::size_t i = 0; i != device_state.input_states.size(); ++i)
       {
-        // We want an input that was initially 0.0 and currently 1.0.
-        const auto detection_score =
-            (input_state.input.GetState() - std::abs(input_state.initial_state));
-
-        if (detection_score > INPUT_DETECT_THRESHOLD)
-          return {device_state.device, &input_state.input};
+        auto& input_state = device_state.input_states[i];
+        input_state.Update();
+
+        if (input_state.IsPressed())
+        {
+          input_state.is_ready = false;
+
+          // Digital presses will evaluate as 1 here.
+          // Analog presses will evaluate greater than 1.
+          const auto smoothness =
+              1 / std::sqrt(input_state.stats.Variance() / input_state.stats.Mean());
+
+          InputDetection new_detection;
+          new_detection.device = device_state.device;
+          new_detection.input = input_state.input;
+          new_detection.press_time = Clock::now();
+          new_detection.smoothness = smoothness;
+
+          // We found an input. Add it to our detections.
+          detections.emplace_back(std::move(new_detection));
+        }
       }
     }
+
+    // Check for any releases of our detected inputs.
+    for (auto& d : detections)
+    {
+      if (!d.release_time.has_value() && d.input->GetState() < (1 - INPUT_DETECT_THRESHOLD))
+        d.release_time = Clock::now();
+    }
   }
 
-  // No input was detected. :'(
-  return {};
+  return detections;
 }
 }  // namespace ciface::Core
diff --git a/Source/Core/InputCommon/ControllerInterface/Device.h b/Source/Core/InputCommon/ControllerInterface/Device.h
index d923d97076..2612f59627 100644
--- a/Source/Core/InputCommon/ControllerInterface/Device.h
+++ b/Source/Core/InputCommon/ControllerInterface/Device.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <chrono>
 #include <memory>
 #include <mutex>
 #include <optional>
@@ -85,6 +86,11 @@ public:
     virtual ControlState GetState() const = 0;
 
     Input* ToInput() override { return this; }
+
+    // Overridden by CombinedInput,
+    // so hotkey logic knows Ctrl, L_Ctrl, and R_Ctrl are the same,
+    // and so input detection can return the parent name.
+    virtual bool IsChild(const Input*) const { return false; }
   };
 
   //
@@ -119,6 +125,8 @@ public:
   const std::vector<Input*>& Inputs() const { return m_inputs; }
   const std::vector<Output*>& Outputs() const { return m_outputs; }
 
+  Input* GetParentMostInput(Input* input) const;
+
   Input* FindInput(std::string_view name) const;
   Output* FindOutput(std::string_view name) const;
 
@@ -147,6 +155,8 @@ protected:
     AddInput(new FullAnalogSurface(high, low));
   }
 
+  void AddCombinedInput(std::string name, const std::pair<std::string, std::string>& inputs);
+
 private:
   int m_id;
   std::vector<Input*> m_inputs;
@@ -185,6 +195,17 @@ public:
 class DeviceContainer
 {
 public:
+  using Clock = std::chrono::steady_clock;
+
+  struct InputDetection
+  {
+    std::shared_ptr<Device> device;
+    Device::Input* input;
+    Clock::time_point press_time;
+    std::optional<Clock::time_point> release_time;
+    ControlState smoothness;
+  };
+
   Device::Input* FindInput(std::string_view name, const Device* def_dev) const;
   Device::Output* FindOutput(std::string_view name, const Device* def_dev) const;
 
@@ -194,8 +215,10 @@ public:
 
   bool HasConnectedDevice(const DeviceQualifier& qualifier) const;
 
-  std::pair<std::shared_ptr<Device>, Device::Input*>
-  DetectInput(u32 wait_ms, const std::vector<std::string>& device_strings) const;
+  std::vector<InputDetection> DetectInput(const std::vector<std::string>& device_strings,
+                                          std::chrono::milliseconds initial_wait,
+                                          std::chrono::milliseconds confirmation_wait,
+                                          std::chrono::milliseconds maximum_wait) const;
 
 protected:
   mutable std::recursive_mutex m_devices_mutex;
diff --git a/Source/Core/InputCommon/ControllerInterface/Quartz/QuartzKeyboardAndMouse.mm b/Source/Core/InputCommon/ControllerInterface/Quartz/QuartzKeyboardAndMouse.mm
index 7c4673acd7..d594ac9e5f 100644
--- a/Source/Core/InputCommon/ControllerInterface/Quartz/QuartzKeyboardAndMouse.mm
+++ b/Source/Core/InputCommon/ControllerInterface/Quartz/QuartzKeyboardAndMouse.mm
@@ -143,6 +143,11 @@ KeyboardAndMouse::KeyboardAndMouse(void* window)
   for (int keycode = 0; keycode < 0x80; ++keycode)
     AddInput(new Key(keycode));
 
+  // Add combined left/right modifiers with consistent naming across platforms.
+  AddCombinedInput("Alt", {"Left Alt", "Right Alt"});
+  AddCombinedInput("Shift", {"Left Shift", "Right Shift"});
+  AddCombinedInput("Ctrl", {"Left Control", "Right Control"});
+
   m_windowid = [[reinterpret_cast<NSView*>(window) window] windowNumber];
 
   // cursor, with a hax for-loop
diff --git a/Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp b/Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp
index d049f22c8c..9ec1c2be35 100644
--- a/Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/Xlib/XInput2.cpp
@@ -172,6 +172,11 @@ KeyboardMouse::KeyboardMouse(Window window, int opcode, int pointer, int keyboar
       delete temp_key;
   }
 
+  // Add combined left/right modifiers with consistent naming across platforms.
+  AddCombinedInput("Alt", {"Alt_L", "Alt_R"});
+  AddCombinedInput("Shift", {"Shift_L", "Shift_R"});
+  AddCombinedInput("Ctrl", {"Control_L", "Control_R"});
+
   // Mouse Buttons
   for (int i = 0; i < 32; i++)
     AddInput(new Button(i, &m_state.buttons));