--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dep/animone/src/a11y/win32.cc	Wed Jun 19 23:13:55 2024 -0400
@@ -0,0 +1,243 @@
+#include <functional>
+#include <string>
+#include <vector>
+
+#include <windows.h>
+#include <uiautomation.h>
+
+#include "animone/a11y.h"
+#include "animone/a11y/win32.h"
+
+namespace animone::internal::win32 {
+
+// Windows Accessibility API reference:
+// https://msdn.microsoft.com/en-us/library/windows/desktop/ff486375.aspx
+
+// Commonly used interfaces
+using Element = IUIAutomationElement;
+using TreeWalker = IUIAutomationTreeWalker;
+using ValuePattern = IUIAutomationValuePattern;
+
+using element_proc_t = std::function<TreeScope(Element&)>;
+using properties_t = std::vector<std::pair<long, bool>>;
+
+// The main interface that is used throughout this file. Must be initialized
+// before it can be used for the first time.
+static ComInterface<IUIAutomation> ui_automation;
+
+////////////////////////////////////////////////////////////////////////////////
+
+static bool InitializeUIAutomation() {
+	if (ui_automation)
+		return true;
+
+	// COM library must be initialized on the current thread before calling
+	// CoCreateInstance.
+	::CoInitialize(nullptr);
+
+	IUIAutomation* ui_automation_interface = nullptr;
+	const auto result = ::CoCreateInstance(
+			CLSID_CUIAutomation, nullptr, CLSCTX_INPROC_SERVER, IID_IUIAutomation,
+			reinterpret_cast<void**>(&ui_automation_interface));
+	ui_automation.reset(ui_automation_interface);
+
+	return SUCCEEDED(result);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+static Element* GetElementFromHandle(HWND hwnd) {
+	Element* element = nullptr;
+	ui_automation->ElementFromHandle(static_cast<UIA_HWND>(hwnd), &element);
+	return element;
+}
+
+static std::wstring GetElementName(Element& element) {
+	std::wstring element_name;
+
+	BSTR bstr = nullptr;
+	if (SUCCEEDED(element.get_CurrentName(&bstr)) && bstr) {
+		element_name = bstr;
+		::SysFreeString(bstr);
+	}
+
+	return element_name;
+}
+
+static std::wstring GetElementValue(Element& element) {
+	std::wstring element_value;
+
+	ValuePattern* value_pattern_interface = nullptr;
+	element.GetCurrentPatternAs(
+			UIA_ValuePatternId, IID_PPV_ARGS(&value_pattern_interface));
+	ComInterface<ValuePattern> value_pattern(value_pattern_interface);
+
+	if (value_pattern) {
+		BSTR bstr = nullptr;
+		if (SUCCEEDED(value_pattern->get_CurrentValue(&bstr)) && bstr) {
+			element_value = bstr;
+			::SysFreeString(bstr);
+		}
+	}
+
+	return element_value;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+static bool VerifyElementProperties(Element& element, const properties_t& properties) {
+	VARIANT v = {};
+	for (const auto& pair : properties) {
+		if (FAILED(element.GetCurrentPropertyValue(pair.first, &v)))
+			return false;
+		if (v.boolVal != (pair.second ? VARIANT_TRUE : VARIANT_FALSE))
+			return false;
+	}
+
+	return true;
+}
+
+static bool IsAddressBarElement(Element& element) {
+	static const properties_t properties = {
+		{UIA_IsEnabledPropertyId, true},
+		{UIA_IsKeyboardFocusablePropertyId, true},
+		{UIA_IsValuePatternAvailablePropertyId, true},
+		{UIA_ValueIsReadOnlyPropertyId, false},
+	};
+
+	return VerifyElementProperties(element, properties);
+}
+
+static bool IsTabsElement(Element& element) {
+	static const properties_t properties = {
+		{UIA_ValueIsReadOnlyPropertyId, true},
+	};
+
+	return VerifyElementProperties(element, properties);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+static void WalkElements(TreeWalker& tree_walker, Element& parent, TreeScope scope,
+                         size_t depth, element_proc_t element_proc) {
+	constexpr size_t kMaxTreeDepth = 16;  // arbitrary value
+	if (depth > kMaxTreeDepth)
+		return;
+
+	if (scope & TreeScope_Element)
+		scope = element_proc(parent);
+
+	auto descend = [](TreeScope scope) {
+		return (scope & TreeScope_Children) || (scope & TreeScope_Descendants);
+	};
+
+	if (descend(scope)) {
+		Element* first_element = nullptr;
+		tree_walker.GetFirstChildElement(&parent, &first_element);
+		ComInterface<Element> element(first_element);
+
+		while (element) {
+			scope = element_proc(*element);
+
+			if (descend(scope))
+				WalkElements(tree_walker, *element, scope, depth + 1, element_proc);
+
+			Element* next_element = nullptr;
+			tree_walker.GetNextSiblingElement(element.get(), &next_element);
+			element.reset(next_element);
+		}
+	}
+}
+
+static bool FindWebBrowserElements(Element& parent, std::wstring& address,
+                                   std::vector<std::wstring>& tabs) {
+	TreeWalker* tree_walker_interface = nullptr;
+	ui_automation->get_ControlViewWalker(&tree_walker_interface);
+	ComInterface<TreeWalker> tree_walker(tree_walker_interface);
+
+	if (!tree_walker)
+		return false;
+
+	auto element_proc = [&](Element& element) -> TreeScope {
+		CONTROLTYPEID control_type_id = 0;
+		element.get_CurrentControlType(&control_type_id);
+
+		switch (control_type_id) {
+			default:
+				// Are we done?
+				if (!address.empty() && !tabs.empty())
+					return TreeScope_Element;
+				// Otherwise continue descending the tree.
+				return TreeScope_Descendants;
+
+			case UIA_DocumentControlTypeId:
+			case UIA_MenuBarControlTypeId:
+			case UIA_TitleBarControlTypeId:
+				// We do not need to walk through these nodes. In fact, skipping
+				// documents dramatically improves our performance on worst case
+				// scenarios. This is the whole reason we are walking the tree rather
+				// than using FindFirst and FindAll methods.
+				return TreeScope_Element;
+
+			case UIA_EditControlTypeId:
+				// Here we assume that the first edit control that fits our properties
+				// is the address bar (e.g. "Omnibox" on Chrome, "Awesome Bar" on
+				// Firefox). This element is named differently on each web browser
+				// (e.g. "Address and search bar" on Chrome, "Search or enter address"
+				// on Firefox). This name can change depending on the browser
+				// language. However, we are only interested in the element value,
+				// which usually gives us the URL of the current page.
+				if (address.empty() && IsAddressBarElement(element)) {
+					address = GetElementValue(element);
+					return TreeScope_Element;
+				} else {
+					// Opera has an edit control ("Address field") within another edit
+					// control ("Address bar").
+					return TreeScope_Descendants;
+				}
+
+			case UIA_TabControlTypeId:
+				if (tabs.empty() && IsTabsElement(element))
+					return TreeScope_Children;
+				return TreeScope_Element;
+
+			case UIA_TabItemControlTypeId:
+				tabs.push_back(GetElementName(element));
+				return TreeScope_Element;
+		}
+	};
+
+	WalkElements(*tree_walker, parent, TreeScope_Subtree, 0, element_proc);
+	return true;
+}
+
+/* ------------------------------------------------------------------------------------ */
+
+bool GetWebBrowserInformation(const Window& window, web_browser_proc_t web_browser_proc) {
+	if (!web_browser_proc)
+		return false;
+
+	if (!InitializeUIAutomation())
+		return false;
+
+	ComInterface<Element> parent(GetElementFromHandle(hwnd));
+	if (!parent)
+		return false;
+
+	const std::string title = ToUtf8String(GetElementName(*parent));
+	web_browser_proc({WebBrowserInformationType::Title, title});
+
+	std::wstring address;
+	std::vector<std::wstring> tabs;
+
+	if (!FindWebBrowserElements(*parent, address, tabs))
+		return false;
+
+	web_browser_proc({WebBrowserInformationType::Address, ToUtf8String(address)});
+	for (const auto& tab : tabs)
+		web_browser_proc({WebBrowserInformationType::Tab, ToUtf8String(tab)});
+
+	return true;
+}
+
+}  // namespace animone::internal::win32