[fix] correct Windows remote control session routing and key mapping

apps/desktop/src/platform/windows/service/interactive_desktop.h

@@ -8,6 +8,7 @@
 #define _INTERACTIVE_DESKTOP_H_
 
 #include <Windows.h>
+#include <WtsApi32.h>
 
 #include <string>
 
@@ -33,6 +34,52 @@ inline std::wstring GetDesktopNameW(HDESK desktop) {
   return name;
 }
 
+inline bool IsDesktopReceivingInput(HDESK desktop) {
+  BOOL receiving_input = FALSE;
+  return desktop != nullptr &&
+         GetUserObjectInformationW(desktop, UOI_IO, &receiving_input,
+                                   sizeof(receiving_input), nullptr) &&
+         receiving_input != FALSE;
+}
+
+inline bool IsCurrentProcessSession(DWORD session_id) {
+  DWORD process_session_id = 0xFFFFFFFF;
+  return session_id != 0xFFFFFFFF &&
+         ProcessIdToSessionId(GetCurrentProcessId(), &process_session_id) &&
+         session_id == process_session_id;
+}
+
+inline bool IsCurrentSessionUnlocked() {
+  DWORD session_id = 0xFFFFFFFF;
+  if (!ProcessIdToSessionId(GetCurrentProcessId(), &session_id)) return false;
+  PWTSINFOEXW info = nullptr;
+  DWORD bytes = 0;
+  if (!WTSQuerySessionInformationW(
+          WTS_CURRENT_SERVER_HANDLE, session_id, WTSSessionInfoEx,
+          reinterpret_cast<LPWSTR*>(&info), &bytes)) {
+    return false;
+  }
+  const bool unlocked =
+      info != nullptr && bytes >= sizeof(WTSINFOEXW) && info->Level == 1 &&
+      info->Data.WTSInfoExLevel1.SessionState == WTSActive &&
+      info->Data.WTSInfoExLevel1.SessionFlags == WTS_SESSIONSTATE_UNLOCK;
+  if (info != nullptr) WTSFreeMemory(info);
+  return unlocked;
+}
+
+inline bool IsCurrentSessionUserDesktopActive() {
+  // LockApp can be visible on Default while the session is still locked.
+  if (!IsCurrentSessionUnlocked()) return false;
+  HDESK desktop = OpenInputDesktop(0, FALSE, DESKTOP_READOBJECTS);
+  if (desktop == nullptr) return false;
+  // OpenInputDesktop also succeeds in disconnected RDP sessions. The name
+  // alone does not tell us whether this desktop can currently receive input.
+  const bool active = IsDesktopReceivingInput(desktop) &&
+                      _wcsicmp(GetDesktopNameW(desktop).c_str(), L"Default") == 0;
+  CloseDesktop(desktop);
+  return active;
+}
+
 // Use only on worker threads without windows or hooks. Restore the original
 // desktop before closing the handle: Windows cannot close a desktop in use.
 class ScopedInteractiveDesktop {
@@ -88,6 +135,10 @@ class ScopedInteractiveDesktop {
     return !name_.empty() && _wcsicmp(name_.c_str(), input_name.c_str()) == 0;
   }
 
+  bool IsReceivingInput() const {
+    return IsDesktopReceivingInput(desktop_);
+  }
+
   const std::wstring& name() const { return name_; }
 
  private: