Implement finding grandchildren windows on X11

Fixes #33, improves code structure and uses variable names in accordance with X11 manual

Author: dancesWithBugs

src/linux/window_manager.cc

@@ -2,69 +2,124 @@
 #include <X11/Xutil.h>
 #include "../window_manager.h"
 extern "C" {
-    #include "../xdisplay.h"
+	#include "../xdisplay.h"
 }
 
 WindowHandle getActiveWindow() {
-    Display* xServer = XGetMainDisplay();
-    Window window;
-    if (xServer != NULL) {
-        int32_t revertToWindow;
-        XGetInputFocus(xServer, &window, &revertToWindow);
-        return window;
-    }
-    return -1;
+	Display* display;
+	Window focus;
+	int32_t revert_to;
+
+	display = XGetMainDisplay();
+	if (display == NULL) {
+		return -1;
+	}
+
+	XGetInputFocus(display, &focus, &revert_to);
+	return focus;
+}
+
+std::vector<WindowHandle> getWindowsRecursive(Display* display, Window w) {
+	std::vector<WindowHandle> windowHandles;
+	std::vector<WindowHandle> childrenWindowHandles;
+	Window root, parent;
+	Window* children;
+	uint32_t nchildren;
+
+	if (!XQueryTree(display, w, &root, &parent, &children, &nchildren)) {
+		return windowHandles;
+	}
+
+	if (children != NULL) {
+		for (uint32_t i = 0; i < nchildren; i++) {
+			windowHandles.push_back(children[i]);
+			childrenWindowHandles = getWindowsRecursive(display, children[i]);
+			windowHandles.insert(windowHandles.end(), childrenWindowHandles.begin(), childrenWindowHandles.end());
+		}
+		XFree(children);
+	}
+
+	return windowHandles;
 }
 
 std::vector<WindowHandle> getWindows() {
-    Display* xServer = XGetMainDisplay();
-    std::vector<WindowHandle> windowHandles;
-    if (xServer != NULL) {
-        Window defaultRootWindow = DefaultRootWindow(xServer);
-        Window rootWindow;
-        Window parentWindow;
-        Window* windowList;
-        uint32_t windowCount;
-
-        Status queryTreeResult = XQueryTree(xServer, defaultRootWindow, &rootWindow, &parentWindow, &windowList, &windowCount);
-        if (queryTreeResult > 0) {
-            for (size_t idx = 0; idx < windowCount; ++idx) {
-                windowHandles.push_back(windowList[idx]);
-            }
-        }
-    }
-    return windowHandles;
+	Display* display;
+	Window root;
+	std::vector<WindowHandle> windowHandles;
+
+	display = XGetMainDisplay();
+	if (display == NULL) {
+		return windowHandles;
+	}
+
+	root = DefaultRootWindow(display);
+	windowHandles = getWindowsRecursive(display, root);
+
+	return windowHandles;
 }
 
 std::string getWindowTitle(const WindowHandle windowHandle) {
-    Display* xServer = XGetMainDisplay();
-    std::string windowName = "";
-    if (xServer != NULL && windowHandle >= 0) {
-        /*
-         * While there's also `XFetchName` to retrieve a window's `WM_NAME` property, in my tests `XFetchName` always failed and return 0
-         * `XGetWMName` on the other hand just worked as expected.
-         * Keep that in mind in case you're considering changing this implementation
-         */
-        XTextProperty windowTextProperty;
-        Status getWMNameResult = XGetWMName(xServer, windowHandle, &windowTextProperty);
-        if (getWMNameResult > 0) {
-            windowName = std::string(reinterpret_cast<const char*>(windowTextProperty.value));
-        }
-    }
-    return windowName;
+	Display* display;
+	XTextProperty text_prop;
+
+	display = XGetMainDisplay();
+	if (display == NULL || windowHandle < 0) {
+		return "";
+	}
+
+	/*
+	* While there's also `XFetchName` to retrieve a window's `WM_NAME` property, in my tests `XFetchName` always failed and return 0
+	* `XGetWMName` on the other hand just worked as expected.
+	* Keep that in mind in case you're considering changing this implementation
+	*/
+	if (!XGetWMName(display, windowHandle, &text_prop)) {
+		return "";
+	}
+
+	return std::string(reinterpret_cast<const char*>(text_prop.value));
+}
+
+MMPoint getAbsoluteOriginRecursive(Display* display, const WindowHandle w, MMPoint origin) {
+	Window root, parent;
+	Window* children;
+	int32_t x, y;
+	uint32_t width, height, border_width, border_height, nchildren;
+
+	if (!XQueryTree(display, w, &root, &parent, &children, &nchildren)) {
+		return MMPointMake(0,0);
+	}
+	if (children != NULL) {
+		XFree(children);
+	}
+	if (parent == root) {
+		return origin;
+	}
+
+	if (!XGetGeometry(display, parent, &root, &x, &y, &width, &height, &border_width, &border_height)) {
+		return MMPointMake(0,0);
+	}
+	origin.x += x;
+	origin.y += y;
+
+	return getAbsoluteOriginRecursive(display, parent, origin);
 }
 
-MMRect getWindowRect(const WindowHandle windowHandle) {
-    Display* xServer = XGetMainDisplay();
-    MMRect windowRect = MMRectMake(0, 0, 0, 0);
-    if (xServer != NULL && windowHandle >= 0) {
-        Window rootWindow;
-        int32_t x, y;
-        uint32_t width, height, border_width, border_height;
-        Status getXGeometryResult = XGetGeometry(xServer, windowHandle, &rootWindow, &x, &y, &width, &height, &border_width, &border_height);
-        if (getXGeometryResult > 0) {
-            windowRect = MMRectMake(x, y, width, height);
-        }
-    }
-    return windowRect;
+MMRect getWindowRect(const WindowHandle w) {
+	Display* display;
+	Window root;
+	int32_t x, y;
+	uint32_t width, height, border_width, border_height;
+	MMPoint absoluteOrigin;
+
+	display = XGetMainDisplay();
+	if (display == NULL || w < 0) {
+		return MMRectMake(0, 0, 0, 0);
+	}
+
+	if (!XGetGeometry(display, w, &root, &x, &y, &width, &height, &border_width, &border_height)) {
+		return MMRectMake(0, 0, 0, 0);
+	}
+	absoluteOrigin = getAbsoluteOriginRecursive(display, w, MMPointMake(x, y));
+
+	return MMRectMake(absoluteOrigin.x, absoluteOrigin.y, width, height);
 }