feat: implement findChild* methods

Plugins/ZShell/zutils.cpp

@@ -214,6 +214,74 @@ QString ZUtils::enumToString(
 	return QString::fromUtf8(key);
 }
 
+namespace {
+
+template <typename Predicate>
+QQuickItem* findChildDfs(QQuickItem* root, Predicate&& match) {
+	const auto children = root->childItems();
+	for (QQuickItem* const child : children) {
+		if (match(child)) {
+			return child;
+		}
+		if (QQuickItem* const found = findChildDfs(child, match)) {
+			return found;
+		}
+	}
+	return nullptr;
+}
+
+template <typename Predicate>
+void findChildrenDfs(
+	QQuickItem* root, Predicate&& match, QList<QQuickItem*>& out) {
+	const auto children = root->childItems();
+	for (QQuickItem* const child : children) {
+		if (match(child)) {
+			out.append(child);
+		}
+		findChildrenDfs(child, match, out);
+	}
+}
+
+} // namespace
+
+QQuickItem* ZUtils::findChild(QQuickItem* root, const QString& name) {
+	if (!root) {
+		return nullptr;
+	}
+
+	return findChildDfs(root, [&name](const QQuickItem* item) {
+		return item->objectName() == name;
+	});
+}
+
+QList<QQuickItem*> ZUtils::findChildren(QQuickItem* root, const QString& name) {
+	QList<QQuickItem*> children;
+	if (root) {
+		findChildrenDfs(
+			root,
+			[&name](const QQuickItem* item) {
+				return item->objectName() == name;
+			},
+			children);
+	}
+	return children;
+}
+
+QList<QQuickItem*> ZUtils::findChildrenMatching(
+	QQuickItem* root, const QString& pattern) {
+	QList<QQuickItem*> children;
+	if (root) {
+		const QRegularExpression re(pattern);
+		findChildrenDfs(
+			root,
+			[&re](const QQuickItem* item) {
+				return re.match(item->objectName()).hasMatch();
+			},
+			children);
+	}
+	return children;
+}
+
 #ifndef ZSHELL_VERSION
 #define ZSHELL_VERSION ""
 #endif