From b49e5cfc7013cef7e9af79d17e04f7e7e4c377d4 Mon Sep 17 00:00:00 2001
From: Kahrl <kahrl@gmx.net>
Date: Fri, 24 Oct 2014 16:22:05 +0200
Subject: [PATCH] Remove m_ext_ptr in GUIFormSpecMenu, replaced by refcount
 mechanism

---
 src/game.cpp            | 26 ++++++++++++++++++++++----
 src/guiEngine.cpp       |  5 ++---
 src/guiFormSpecMenu.cpp |  9 +--------
 src/guiFormSpecMenu.h   |  2 --
 src/modalMenu.h         |  2 ++
 5 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/src/game.cpp b/src/game.cpp
index 2f228b0ed..2e4485e36 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -944,9 +944,16 @@ static inline void create_formspec_menu(GUIFormSpecMenu** cur_formspec,
 
 	if (*cur_formspec == 0) {
 		*cur_formspec = new GUIFormSpecMenu(device, guiroot, -1, &g_menumgr,
-				invmgr, gamedef, tsrc, fs_src, txt_dest, cur_formspec, client);
+				invmgr, gamedef, tsrc, fs_src, txt_dest, client);
 		(*cur_formspec)->doPause = false;
-		(*cur_formspec)->drop();
+
+		/*
+			Caution: do not call (*cur_formspec)->drop() here --
+			the reference might outlive the menu, so we will
+			periodically check if *cur_formspec is the only
+			remaining reference (i.e. the menu was removed)
+			and delete it in that case.
+		*/
 	}
 	else {
 		(*cur_formspec)->setFormSource(fs_src);
@@ -3417,10 +3424,16 @@ void the_game(bool &kill, bool random_input, InputHandler *input,
 		}
 
 		/*
-			make sure menu is on top
+			1. Delete formspec menu reference if menu was removed
+			2. Else, make sure formspec menu is on top
 		*/
-		if ((!noMenuActive()) && (current_formspec)) {
+		if (current_formspec) {
+			if (current_formspec->getReferenceCount() == 1) {
+				current_formspec->drop();
+				current_formspec = NULL;
+			} else if (!noMenuActive()) {
 				guiroot->bringToFront(current_formspec);
+			}
 		}
 
 		/*
@@ -3509,6 +3522,11 @@ void the_game(bool &kill, bool random_input, InputHandler *input,
 		g_menumgr.m_stack.front()->setVisible(false);
 		g_menumgr.deletingMenu(g_menumgr.m_stack.front());
 	}
+	if (current_formspec) {
+		current_formspec->drop();
+		current_formspec = NULL;
+	}
+
 	/*
 		Draw a "shutting down" screen, which will be shown while the map
 		generator and other stuff quits
diff --git a/src/guiEngine.cpp b/src/guiEngine.cpp
index 41a522caf..e53b52b01 100644
--- a/src/guiEngine.cpp
+++ b/src/guiEngine.cpp
@@ -190,7 +190,7 @@ GUIEngine::GUIEngine(	irr::IrrlichtDevice* dev,
 			m_texture_source,
 			m_formspecgui,
 			m_buttonhandler,
-			NULL, NULL);
+			NULL);
 
 	m_menu->allowClose(false);
 	m_menu->lockSize(true,v2u32(800,600));
@@ -220,8 +220,7 @@ GUIEngine::GUIEngine(	irr::IrrlichtDevice* dev,
 	}
 
 	m_menu->quitMenu();
-	m_menu->remove();
-	delete m_menu;
+	m_menu->drop();
 	m_menu = NULL;
 }
 
diff --git a/src/guiFormSpecMenu.cpp b/src/guiFormSpecMenu.cpp
index a502c9682..e82ea829c 100644
--- a/src/guiFormSpecMenu.cpp
+++ b/src/guiFormSpecMenu.cpp
@@ -68,12 +68,11 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 /*
 	GUIFormSpecMenu
 */
-
 GUIFormSpecMenu::GUIFormSpecMenu(irr::IrrlichtDevice* dev,
 		gui::IGUIElement* parent, s32 id, IMenuManager *menumgr,
 		InventoryManager *invmgr, IGameDef *gamedef,
 		ISimpleTextureSource *tsrc, IFormSource* fsrc, TextDest* tdst,
-		GUIFormSpecMenu** ext_ptr, Client* client) :
+		Client* client) :
 	GUIModalMenu(dev->getGUIEnvironment(), parent, id, menumgr),
 	m_device(dev),
 	m_invmgr(invmgr),
@@ -89,7 +88,6 @@ GUIFormSpecMenu::GUIFormSpecMenu(irr::IrrlichtDevice* dev,
 	m_lock(false),
 	m_form_src(fsrc),
 	m_text_dst(tdst),
-	m_ext_ptr(ext_ptr),
 	m_font(dev->getGUIEnvironment()->getSkin()->getFont()),
 	m_formspec_version(0)
 #ifdef __ANDROID__
@@ -130,11 +128,6 @@ GUIFormSpecMenu::~GUIFormSpecMenu()
 	if (m_text_dst != NULL) {
 		delete m_text_dst;
 	}
-
-	if (m_ext_ptr != NULL) {
-		assert(*m_ext_ptr == this);
-		*m_ext_ptr = NULL;
-	}
 }
 
 void GUIFormSpecMenu::removeChildren()
diff --git a/src/guiFormSpecMenu.h b/src/guiFormSpecMenu.h
index 40be59b46..d38e9ec46 100644
--- a/src/guiFormSpecMenu.h
+++ b/src/guiFormSpecMenu.h
@@ -210,7 +210,6 @@ public:
 			ISimpleTextureSource *tsrc,
 			IFormSource* fs_src,
 			TextDest* txt_dst,
-			GUIFormSpecMenu** ext_ptr,
 			Client* client
 			);
 
@@ -346,7 +345,6 @@ protected:
 private:
 	IFormSource      *m_form_src;
 	TextDest         *m_text_dst;
-	GUIFormSpecMenu **m_ext_ptr;
 	gui::IGUIFont    *m_font;
 	unsigned int      m_formspec_version;
 
diff --git a/src/modalMenu.h b/src/modalMenu.h
index 2c512d3ca..72ecedcb9 100644
--- a/src/modalMenu.h
+++ b/src/modalMenu.h
@@ -96,6 +96,8 @@ public:
 
 		WARNING: THIS DEALLOCATES THE MENU FROM MEMORY. Return
 		immediately if you call this from the menu itself.
+
+		(More precisely, this decrements the reference count.)
 	*/
 	void quitMenu()
 	{