[fix][cleanup] Use std::unique_ptr for TextBox, and so fix memory…

…leak.

include/guisan/widgets/textbox.hpp

@@ -57,15 +57,15 @@
 #ifndef GCN_TEXTBOX_HPP
 #define GCN_TEXTBOX_HPP
 
-#include <ctime>
-#include <string>
-#include <vector>
-
 #include "guisan/keylistener.hpp"
 #include "guisan/mouselistener.hpp"
 #include "guisan/platform.hpp"
 #include "guisan/widget.hpp"
 
+#include <memory>
+#include <string>
+#include <vector>
+
 namespace gcn
 {
     class Text;
@@ -91,6 +91,11 @@ namespace gcn
          */
         TextBox(const std::string& text);
 
+        /**
+         * Destructor.
+         */
+        ~TextBox() override;
+
         /**
          * Sets the text of the text box.
          *
@@ -272,7 +277,7 @@ namespace gcn
         /**
          * Holds the text of the text box.
          */
-        Text* mText = nullptr;
+        std::unique_ptr<Text> mText;
 
         /**
          * True if the text box is editable, false otherwise.

src/widgets/textbox.cpp

@@ -71,7 +71,7 @@ namespace gcn
     TextBox::TextBox() : TextBox("")
     {}
 
-    TextBox::TextBox(const std::string& text) : mText(new Text(text))
+    TextBox::TextBox(const std::string& text) : mText(std::make_unique<Text>(text))
     {
         setFocusable(true);
 
@@ -81,6 +81,8 @@ namespace gcn
         setFrameSize(1);
     }
 
+    TextBox::~TextBox() = default;
+
     void TextBox::setText(const std::string& text)
     {
         mText->setContent(text);