Let BALM::{X|Y}Tabs be in multiple BALMLayouts, if they are friendly.

headers/libs/alm/ALMLayout.h

@@ -151,6 +151,17 @@ private:
 								BALMLayout(const BALMLayout&);
 			void				operator =(const BALMLayout&);
 
+	struct XTabRemover;
+	struct XTabRemoverFunc;
+
+	struct YTabRemover;
+	struct YTabRemoverFunc;
+
+	friend struct XTabRemover;
+	friend struct XTabRemoverFunc;
+
+	friend struct YTabRemover;
+	friend struct YTabRemoverFunc;
 
 	friend class XTab;
 	friend class YTab;
@@ -159,6 +170,9 @@ private:
 			float				InsetForTab(XTab* tab) const;
 			float				InsetForTab(YTab* tab) const;
 
+			void				_RemoveSelfFromTab(XTab* tab);
+			void				_RemoveSelfFromTab(YTab* tab);
+
 			BLayoutItem*		_LayoutItemToAdd(BView* view);
 
 			void				_UpdateAreaConstraints();

headers/libs/alm/Tab.h

@@ -29,7 +29,14 @@ protected:
 								XTab(BALMLayout* layout);
 
 private:
-			BALMLayout*			fALMLayout;
+			struct BALMLayoutList;
+
+			bool				IsInLayout(BALMLayout* layout);
+			bool				AddedToLayout(BALMLayout* layout);
+			void				LayoutLeaving(BALMLayout* layout);
+			bool				IsSuitableFor(BALMLayout* layout);
+
+			BALMLayoutList*		fLayouts;
 
 			uint32				_reserved[2];
 };
@@ -44,7 +51,12 @@ protected:
 								YTab(BALMLayout* layout);
 
 private:
-			BALMLayout*			fALMLayout;
+			bool				IsInLayout(BALMLayout* layout);
+			bool				AddedToLayout(BALMLayout* layout);
+			void				LayoutLeaving(BALMLayout* layout);
+			bool				IsSuitableFor(BALMLayout* layout);
+
+			XTab::BALMLayoutList* fLayouts;
 
 			uint32				_reserved[2];
 };

src/libs/alm/ALMLayout.cpp

@@ -11,18 +11,70 @@
 
 #include <vector>
 
+#include <AutoDeleter.h>
 #include <ControlLook.h>
 
 #include "RowColumnManager.h"
 #include "ViewLayoutItem.h"
 
 
+using BPrivate::AutoDeleter;
 using namespace LinearProgramming;
 
 
 const BSize kUnsetSize(B_SIZE_UNSET, B_SIZE_UNSET);
 
 
+struct BALMLayout::XTabRemoverFunc {
+	void operator()(XTab* tab)
+	{
+		if (tab)
+			layout->_RemoveSelfFromTab(tab);
+	}
+
+	BALMLayout* layout;
+};
+
+
+struct BALMLayout::XTabRemover
+	: public AutoDeleter<XTab, BALMLayout::XTabRemoverFunc> {
+	
+	typedef AutoDeleter<XTab, BALMLayout::XTabRemoverFunc> Base;
+
+	XTabRemover(BALMLayout* layout, XTab* tab = NULL)
+		:
+		Base(tab)
+	{
+		fDelete.layout = layout;
+	}
+};
+
+
+struct BALMLayout::YTabRemoverFunc {
+	void operator()(YTab* tab)
+	{
+		if (tab)
+			layout->_RemoveSelfFromTab(tab);
+	}
+
+	BALMLayout* layout;
+};
+
+
+struct BALMLayout::YTabRemover
+	: public AutoDeleter<YTab, BALMLayout::YTabRemoverFunc> {
+	
+	typedef AutoDeleter<YTab, BALMLayout::YTabRemoverFunc> Base;
+
+	YTabRemover(BALMLayout* layout, YTab* tab = NULL)
+		:
+		Base(tab)
+	{
+		fDelete.layout = layout;
+	}
+};
+
+
 BALM::BALMLayout::BadLayoutPolicy::~BadLayoutPolicy()
 {
 }
@@ -105,6 +157,10 @@ BALMLayout::AddXTab()
 		return NULL;
 
 	fXTabList.AddItem(tab);
+	if (!tab->AddedToLayout(this)) {
+		fXTabList.RemoveItem(tab);
+		return NULL;
+	}
 	return tab;
 }
 
@@ -140,6 +196,10 @@ BALMLayout::AddYTab()
 		return NULL;
 
 	fYTabList.AddItem(tab);
+	if (!tab->AddedToLayout(this)) {
+		fYTabList.RemoveItem(tab);
+		return NULL;
+	}
 	return tab;
 }
 
@@ -480,6 +540,11 @@ Area*
 BALMLayout::AddItem(BLayoutItem* item, XTab* left, YTab* top, XTab* _right,
 	YTab* _bottom)
 {
+	if (!left->IsSuitableFor(this) || !top->IsSuitableFor(this)
+			|| (_right && !_right->IsSuitableFor(this))
+			|| (_bottom && !_bottom->IsSuitableFor(this)))
+		debugger("Tab added to unfriendly layout!");
+
 	BReference<XTab> right = _right;
 	if (right.Get() == NULL)
 		right = AddXTab();
@@ -487,16 +552,51 @@ BALMLayout::AddItem(BLayoutItem* item, XTab* left, YTab* top, XTab* _right,
 	if (bottom.Get() == NULL)
 		bottom = AddYTab();
 
-	// Area is added int ItemAdded
+		// TODO: make sure all tabs get into the lists
+	XTabRemover leftRemover(this);
+	if (!left->IsInLayout(this)) {
+		if (!left->AddedToLayout(this))
+			return NULL;
+		leftRemover.SetTo(left);
+	}
+
+	YTabRemover topRemover(this);
+	if (!top->IsInLayout(this)) {
+		if (!top->AddedToLayout(this))
+			return NULL;
+		topRemover.SetTo(top);
+	}
+
+	XTabRemover rightRemover(this);
+	if (_right != NULL && !right->IsInLayout(this)) {
+		if (!right->AddedToLayout(this))
+			return NULL;
+		rightRemover.SetTo(right);
+	}
+
+	YTabRemover bottomRemover(this);
+	if (_bottom != NULL && !bottom->IsInLayout(this)) {
+		if (!bottom->AddedToLayout(this))
+			return NULL;
+		bottomRemover.SetTo(bottom);
+	}
+			
+	// Area is added in ItemAdded
 	if (!BAbstractLayout::AddItem(-1, item))
 		return NULL;
 	Area* area = AreaFor(item);
-	if (!area)
+	if (!area) {
+		RemoveItem(item);
 		return NULL;
+	}
 
 	area->_Init(fSolver, left, top, right, bottom, fRowColumnManager);
-
 	fRowColumnManager->AddArea(area);
+
+	leftRemover.Detach();
+	rightRemover.Detach();
+	topRemover.Detach();
+	bottomRemover.Detach();
 	return area;
 }
 
@@ -907,6 +1007,20 @@ BALMLayout::InsetForTab(YTab* tab) const
 }
 
 
+void
+BALMLayout::_RemoveSelfFromTab(XTab* tab)
+{
+	tab->LayoutLeaving(this);
+}
+
+
+void
+BALMLayout::_RemoveSelfFromTab(YTab* tab)
+{
+	tab->LayoutLeaving(this);
+}
+
+
 BLayoutItem*
 BALMLayout::_LayoutItemToAdd(BView* view)
 {

src/libs/alm/Tab.cpp

@@ -10,29 +10,144 @@
 #include <ALMLayout.h>
 
 
+using std::nothrow;
+
+
+struct XTab::BALMLayoutList {
+	BALMLayoutList(BALMLayout* _layout, BALMLayoutList* _next = NULL)
+		:
+		next(_next),
+		layout(_layout)
+	{
+	}
+
+	~BALMLayoutList()
+	{
+		delete next;
+	}
+
+	bool HasLayout(BALMLayout* search)
+	{
+		if (layout == search)
+			return true;
+		return next ? next->HasLayout(search) : false;
+	}
+
+	BALMLayoutList* Remove(BALMLayout* remove)
+	{
+		if (layout == remove) {
+			BALMLayoutList* _next = next;
+			delete this;
+			return _next;
+		}
+		if (next)
+			next = next->Remove(remove);
+		return this;
+	}
+
+	BALMLayoutList*		next;
+	BALMLayout*			layout;
+};
+
+
 XTab::XTab(BALMLayout* layout)
 	:
 	Variable(layout->Solver()),
-	fALMLayout(layout)
+	fLayouts(new BALMLayoutList(layout))
 {
 }
 
 
 XTab::~XTab()
 {
-	fALMLayout->fXTabList.RemoveItem(this);
+	BALMLayoutList* layouts = fLayouts;
+	while (layouts) {
+		layouts->layout->fXTabList.RemoveItem(this);
+		layouts = layouts->next;
+	}
+	delete fLayouts;
+}
+
+
+bool
+XTab::IsInLayout(BALMLayout* layout)
+{
+	return fLayouts->HasLayout(layout);
+}
+
+
+bool
+XTab::AddedToLayout(BALMLayout* layout)
+{
+	BALMLayoutList* newHead = new (nothrow) BALMLayoutList(layout, fLayouts);
+	if (newHead == NULL)
+		return false;
+	fLayouts = newHead;
+	return true;
+}
+
+
+void
+XTab::LayoutLeaving(BALMLayout* layout)
+{
+	fLayouts = fLayouts->Remove(layout);
+}
+
+
+bool
+XTab::IsSuitableFor(BALMLayout* layout)
+{
+	return (fLayouts->layout->Solver() == layout->Solver());
 }
 
 
 YTab::YTab(BALMLayout* layout)
 	:
 	Variable(layout->Solver()),
-	fALMLayout(layout)
+	fLayouts(new XTab::BALMLayoutList(layout))
 {
 }
 
 
 YTab::~YTab()
 {
-	fALMLayout->fYTabList.RemoveItem(this);
+	XTab::BALMLayoutList* layouts = fLayouts;
+	while (layouts) {
+		layouts->layout->fYTabList.RemoveItem(this);
+		layouts = layouts->next;
+	}
+	delete fLayouts;
+}
+
+
+bool
+YTab::IsInLayout(BALMLayout* layout)
+{
+	return fLayouts->HasLayout(layout);
+}
+
+
+bool
+YTab::AddedToLayout(BALMLayout* layout)
+{
+	XTab::BALMLayoutList* newHead
+		= new (nothrow) XTab::BALMLayoutList(layout, fLayouts);
+	if (newHead == NULL)
+		return false;
+	fLayouts = newHead;
+	return true;
+}
+
+
+void
+YTab::LayoutLeaving(BALMLayout* layout)
+{
+	fLayouts = fLayouts->Remove(layout);
+}
+
+
+bool
+YTab::IsSuitableFor(BALMLayout* layout)
+{
+	return (fLayouts->layout->Solver() == layout->Solver());
 }