[fix] restore Windows lock-screen control and improve capture performance, fixes #98

2026-10-20 19:14:39 +08:00 · 2026-09-07 05:29:42 +08:00
parent 2000654792
commit e0cd761bdc
7 changed files with 770 additions and 524 deletions
@@ -0,0 +1,101 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-09-07
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _INTERACTIVE_DESKTOP_H_
+#define _INTERACTIVE_DESKTOP_H_
+
+#include <Windows.h>
+
+#include <string>
+
+namespace crossdesk {
+
+inline std::wstring GetDesktopNameW(HDESK desktop) {
+  DWORD bytes_needed = 0;
+  if (desktop == nullptr) {
+    return {};
+  }
+  GetUserObjectInformationW(desktop, UOI_NAME, nullptr, 0, &bytes_needed);
+  if (bytes_needed == 0) {
+    return {};
+  }
+  std::wstring name(bytes_needed / sizeof(wchar_t), L'\0');
+  if (!GetUserObjectInformationW(desktop, UOI_NAME, name.data(), bytes_needed,
+                                 &bytes_needed)) {
+    return {};
+  }
+  while (!name.empty() && name.back() == L'\0') {
+    name.pop_back();
+  }
+  return name;
+}
+
+// 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 {
+ public:
+  ScopedInteractiveDesktop()
+      : original_(GetThreadDesktop(GetCurrentThreadId())) {}
+  ScopedInteractiveDesktop(const ScopedInteractiveDesktop&) = delete;
+  ScopedInteractiveDesktop& operator=(const ScopedInteractiveDesktop&) = delete;
+
+  ~ScopedInteractiveDesktop() {
+    if (desktop_ != nullptr) {
+      SetThreadDesktop(original_);
+      CloseDesktop(desktop_);
+    }
+  }
+
+  bool Bind(const std::wstring& fallback_name) {
+    constexpr ACCESS_MASK access =
+        DESKTOP_CREATEWINDOW | DESKTOP_WRITEOBJECTS | DESKTOP_READOBJECTS |
+        DESKTOP_SWITCHDESKTOP | DESKTOP_JOURNALPLAYBACK;
+    // SendInput requires playback access on the attached desktop; otherwise
+    // it returns ERROR_ACCESS_DENIED even for a correctly attached SYSTEM helper.
+    // The service's stage/name can lag a lock, unlock, or UAC transition.
+    // Opening a cached desktop can succeed even when it is no longer visible.
+    HDESK desktop = OpenInputDesktop(0, FALSE, access);
+    if (desktop == nullptr && !fallback_name.empty()) {
+      desktop = OpenDesktopW(fallback_name.c_str(), 0, FALSE, access);
+    }
+    if (desktop == nullptr) {
+      return false;
+    }
+    if (!SetThreadDesktop(desktop)) {
+      const DWORD error = GetLastError();
+      CloseDesktop(desktop);
+      SetLastError(error);
+      return false;
+    }
+    if (desktop_ != nullptr) {
+      CloseDesktop(desktop_);
+    }
+    desktop_ = desktop;
+    name_ = GetDesktopNameW(desktop_);
+    return true;
+  }
+
+  bool IsInputDesktop() const {
+    HDESK input = OpenInputDesktop(0, FALSE, DESKTOP_READOBJECTS);
+    if (input == nullptr) {
+      return false;
+    }
+    const std::wstring input_name = GetDesktopNameW(input);
+    CloseDesktop(input);
+    return !name_.empty() && _wcsicmp(name_.c_str(), input_name.c_str()) == 0;
+  }
+
+  const std::wstring& name() const { return name_; }
+
+ private:
+  HDESK original_ = nullptr;
+  HDESK desktop_ = nullptr;
+  std::wstring name_;
+};
+
+}  // namespace crossdesk
+
+#endif