From ade86cc80db32956ed77bd3de1ff3628e19d102e Mon Sep 17 00:00:00 2001
From: ABeltramo <beltramo.ale@gmail.com>
Date: Tue, 23 Jul 2024 19:00:36 +0100
Subject: [PATCH] feat: implemented Moonlight keyboard modifiers

---
 src/moonlight-protocol/moonlight/control.hpp  | 17 +++++++++++-
 .../control/input_handler.cpp                 | 22 ++++++++++++++++
 tests/platforms/linux/wayland-display.cpp     | 26 +++++++++++++++++++
 3 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/src/moonlight-protocol/moonlight/control.hpp b/src/moonlight-protocol/moonlight/control.hpp
index bb05bad1..71212d7d 100644
--- a/src/moonlight-protocol/moonlight/control.hpp
+++ b/src/moonlight-protocol/moonlight/control.hpp
@@ -98,6 +98,21 @@ enum CONTROLLER_BTN : unsigned int {
   Y = 0x8000
 };
 
+enum KEYBOARD_MODIFIERS : char {
+  NONE = 0x00,
+  SHIFT = 0x01,
+  CTRL = 0x02,
+  ALT = 0x04,
+  META = 0x08
+};
+
+enum MOONLIGHT_MODIFIERS : short {
+  M_SHIFT = 0x10,
+  M_CTRL = 0x11,
+  M_ALT = 0xA4,
+  M_META = 0x5B
+};
+
 // make sure these structs are allocated in 1-byte blocks so the data aligns
 // right
 #pragma pack(push, 1)
@@ -141,7 +156,7 @@ struct MOUSE_HSCROLL_PACKET : INPUT_PKT {
 struct KEYBOARD_PACKET : INPUT_PKT {
   unsigned char flags;
   short key_code;
-  unsigned char modifiers;
+  char modifiers;
   short zero1;
 };
 
diff --git a/src/moonlight-server/control/input_handler.cpp b/src/moonlight-server/control/input_handler.cpp
index 072e1f8b..34650f7d 100644
--- a/src/moonlight-server/control/input_handler.cpp
+++ b/src/moonlight-server/control/input_handler.cpp
@@ -298,7 +298,29 @@ void keyboard_key(const KEYBOARD_PACKET &pkt, state::StreamSession &session) {
   short moonlight_key = (short)boost::endian::little_to_native(pkt.key_code) & (short)0x7fff;
   if (session.keyboard->has_value()) {
     if (pkt.type == KEY_PRESS) {
+      // Press the virtual modifiers
+      if (pkt.modifiers & KEYBOARD_MODIFIERS::SHIFT && moonlight_key != M_SHIFT)
+        std::visit([](auto &keyboard) { keyboard.press(M_SHIFT); }, session.keyboard->value());
+      if (pkt.modifiers & KEYBOARD_MODIFIERS::CTRL && moonlight_key != M_CTRL)
+        std::visit([](auto &keyboard) { keyboard.press(M_CTRL); }, session.keyboard->value());
+      if (pkt.modifiers & KEYBOARD_MODIFIERS::ALT && moonlight_key != M_ALT)
+        std::visit([](auto &keyboard) { keyboard.press(M_ALT); }, session.keyboard->value());
+      if (pkt.modifiers & KEYBOARD_MODIFIERS::META && moonlight_key != M_META)
+        std::visit([](auto &keyboard) { keyboard.press(M_META); }, session.keyboard->value());
+
+      // Press the actual key
       std::visit([moonlight_key](auto &keyboard) { keyboard.press(moonlight_key); }, session.keyboard->value());
+
+      // Release the virtual modifiers
+      if (pkt.modifiers & KEYBOARD_MODIFIERS::SHIFT && moonlight_key != M_SHIFT)
+        std::visit([](auto &keyboard) { keyboard.release(M_SHIFT); }, session.keyboard->value());
+      if (pkt.modifiers & KEYBOARD_MODIFIERS::CTRL && moonlight_key != M_CTRL)
+        std::visit([](auto &keyboard) { keyboard.release(M_CTRL); }, session.keyboard->value());
+      if (pkt.modifiers & KEYBOARD_MODIFIERS::ALT && moonlight_key != M_ALT)
+        std::visit([](auto &keyboard) { keyboard.release(M_ALT); }, session.keyboard->value());
+      if (pkt.modifiers & KEYBOARD_MODIFIERS::META && moonlight_key != M_META)
+        std::visit([](auto &keyboard) { keyboard.release(M_META); }, session.keyboard->value());
+
     } else {
       std::visit([moonlight_key](auto &keyboard) { keyboard.release(moonlight_key); }, session.keyboard->value());
     }
diff --git a/tests/platforms/linux/wayland-display.cpp b/tests/platforms/linux/wayland-display.cpp
index e6e4af55..fc04c2b5 100644
--- a/tests/platforms/linux/wayland-display.cpp
+++ b/tests/platforms/linux/wayland-display.cpp
@@ -124,6 +124,32 @@ TEST_CASE("Wayland virtual inputs", "[WAYLAND]") {
     REQUIRE(!k_ev->pressed);
   }
 
+  { // Testing modifiers
+    auto press_SHIFT_A =
+        pkts::KEYBOARD_PACKET{.key_code = boost::endian::native_to_little((short)0x41), .modifiers = pkts::SHIFT};
+    press_SHIFT_A.type = pkts::KEY_PRESS;
+    control::handle_input(session, {}, &press_SHIFT_A);
+    wl_display_roundtrip(wd.get());
+
+    auto k_ev = kb_events_q->pop();
+    // Press SHIFT
+    REQUIRE(k_ev.has_value());
+    REQUIRE(k_ev->keycode == 42);
+    REQUIRE(k_ev->pressed);
+
+    // Press A
+    k_ev = kb_events_q->pop();
+    REQUIRE(k_ev.has_value());
+    REQUIRE(k_ev->keycode == 30);
+    REQUIRE(k_ev->pressed);
+
+    // Release SHIFT
+    k_ev = kb_events_q->pop();
+    REQUIRE(k_ev.has_value());
+    REQUIRE(k_ev->keycode == 42);
+    REQUIRE(!k_ev->pressed);
+  }
+
   // Mouse tests: scroll
   {
     short scroll_amt = 10;