(#15) getActiveWindow implementation on Linux

Author: s1hofmann

src/linux/window_manager.cc

@@ -11,8 +11,20 @@ Display* connectToX() {
     return xDisplay;
 }
 
-int32_t disconnectFromX(Display* connection) {
-    return XCloseDisplay(connection);
+void disconnectFromX(Display* connection) {
+    XCloseDisplay(connection);
+}
+
+WindowHandle getActiveWindow() {
+    Display* xServer = connectToX();
+    Window window;
+    if (xServer != nullptr) {
+        int32_t revertToWindow;
+        XGetInputFocus(xServer, &window, &revertToWindow);
+        disconnectFromX(xServer);
+        return window;
+    }
+    return NULL;
 }
 
 std::vector<WindowHandle> getWindows() {

src/main.cc

@@ -669,6 +669,13 @@ Napi::Number _highlight(const Napi::CallbackInfo &info)
 	return Napi::Number::New(env, 1);
 }
 
+Napi::Number _getActiveWindow(const Napi::CallbackInfo &info) {
+	Napi::Env env = info.Env();
+
+	WindowHandle windowHandle = getActiveWindow();
+	return Napi::Number::New(env, windowHandle);
+}
+
 Napi::Array _getWindows(const Napi::CallbackInfo &info) {
 	Napi::Env env = info.Env();
 
@@ -786,6 +793,7 @@ Napi::Object Init(Napi::Env env, Napi::Object exports) {
 	exports.Set(Napi::String::New(env, "getScreenSize"), Napi::Function::New(env, _getScreenSize));
 	exports.Set(Napi::String::New(env, "highlight"), Napi::Function::New(env, _highlight));
 	exports.Set(Napi::String::New(env, "getWindows"), Napi::Function::New(env, _getWindows));
+	exports.Set(Napi::String::New(env, "getActiveWindow"), Napi::Function::New(env, _getActiveWindow));
 	exports.Set(Napi::String::New(env, "getWindowRect"), Napi::Function::New(env, _getWindowRect));
 	exports.Set(Napi::String::New(env, "getWindowTitle"), Napi::Function::New(env, _getWindowTitle));
 	exports.Set(Napi::String::New(env, "captureScreen"), Napi::Function::New(env, _captureScreen));

src/window_manager.h

@@ -7,6 +7,7 @@
 #include "types.h"
 
 std::vector<WindowHandle> getWindows();
+WindowHandle getActiveWindow();
 
 std::string getWindowTitle(const WindowHandle windowHandle);
 MMRect getWindowRect(const WindowHandle windowHandle);