ref-count SdrObject

Which means we can get rid of the majestic hack of ScCaptionPtr
Previously, SdrObject was manually managed, and the ownership
passed around in very complicated fashion.

Notes:

(*) SvxShape has a strong reference to SdrObject, where
previously it had a weak reference. It is now strong
since otherwise the SdrObject will go away very eagerly.

(*) SdrObject still has a weak reference to SvxShape

(*) In the existing places that an SdrObject is being
deleted, we now just clear the reference

(*) instead of SwVirtFlyDrawObj removing itself from the
page that contains inside it's destructor, make the call site
do the removing from the page.

(*) Needed to take the SolarMutex in UndoManagerHelper_Impl::impl_clear
because this can be called from UNO (e.g. sfx2_complex JUnit test)
and the SdrObjects need the SolarMutex when destructing.

(*) handle a tricky situation with SwDrawVirtObj in the SwDrawModel
destructor because the existing code wants mpDrawObj in
SwAnchoredObject to be sometimes owning, sometimes not, which
results in a cycle with the new code.

Change-Id: I4d79df1660e386388e5d51030653755bca02a163
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/138837
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 3 insertions, 106 deletions

diff --git a/sc/inc/postit.hxx b/sc/inc/postit.hxx
index 8a94402b88ad..36473542e1df 100644
--- a/sc/inc/postit.hxx
+++ b/sc/inc/postit.hxx
@@ -21,6 +21,7 @@
 
 #include <rtl/ustring.hxx>
 #include <svl/itemset.hxx>
+#include <rtl/ref.hxx>
 #include "address.hxx"
 #include "scdllapi.h"
 
@@ -36,110 +37,6 @@ class ScDocument;
 namespace tools { class Rectangle; }
 struct ScCaptionInitData;
 
-/** Some desperate attempt to fight against the caption object ownership mess,
-    to which none of shared/weak/plain pointer is a cure.
- */
-class ScCaptionPtr
-{
-public:
-    ScCaptionPtr();
-    explicit ScCaptionPtr( SdrCaptionObj* p );
-    ScCaptionPtr( const ScCaptionPtr& r );
-    ScCaptionPtr(ScCaptionPtr&& r) noexcept;
-    ~ScCaptionPtr();
-
-    ScCaptionPtr& operator=( const ScCaptionPtr& r );
-    ScCaptionPtr& operator=(ScCaptionPtr&& r) noexcept;
-    explicit operator bool() const    { return mpCaption != nullptr; }
-    const SdrCaptionObj* get() const        { return mpCaption; }
-    SdrCaptionObj* get()        { return mpCaption; }
-    const SdrCaptionObj* operator->() const { return mpCaption; }
-    SdrCaptionObj* operator->() { return mpCaption; }
-    const SdrCaptionObj& operator*() const  { return *mpCaption; }
-    SdrCaptionObj& operator*()  { return *mpCaption; }
-
-    // Does not default to nullptr to make it visually obvious where such is used.
-    void reset( SdrCaptionObj* p );
-
-    /** Insert to draw page. The caption object is owned by the draw page then.
-     */
-    void insertToDrawPage( SdrPage& rDrawPage );
-
-    /** Remove from draw page. The caption object is not owned anymore by the
-        draw page then.
-     */
-    void removeFromDrawPage( SdrPage& rDrawPage );
-
-    /** Remove from draw page and free caption object if no Undo recording.
-     */
-    void removeFromDrawPageAndFree( bool bIgnoreUndo = false );
-
-    /** Release all management of the SdrCaptionObj* in all instances of this
-        list and dissolve. The SdrCaptionObj pointer returned is ready to be
-        managed elsewhere.
-     */
-    SdrCaptionObj* release();
-
-    /** Forget the SdrCaptionObj pointer in this one instance.
-        Decrements a use count but does not destroy the object, it's up to the
-        caller to manage this mess...
-     */
-    void forget();
-
-    /** Flag that this instance is in Undo, so drawing layer owns it. */
-    void setNotOwner();
-
-    oslInterlockedCount getRefs() const;
-
-private:
-
-    struct Head
-    {
-        ScCaptionPtr*       mpFirst;        ///< first in list
-        oslInterlockedCount mnRefs;         ///< use count
-
-        Head() = delete;
-        explicit Head( ScCaptionPtr* );
-    };
-
-    Head*                 mpHead;       ///< points to the "master" entry
-    mutable ScCaptionPtr* mpNext;       ///< next in list
-    SdrCaptionObj*        mpCaption;    ///< the caption object, managed by head master
-    bool                  mbNotOwner;   ///< whether this caption object is owned by something else, e.g. held in Undo
-                                            /* TODO: can that be moved to Head?
-                                             * It's unclear when to reset, so
-                                             * each instance has its own flag.
-                                             * The last reference count
-                                             * decrement automatically has the
-                                             * then current state available.
-                                             * */
-
-    void newHead();             //< Allocate a new Head and init.
-    void incRef() const;
-    bool decRef() const;        //< @returns <TRUE/> if the last reference was decremented.
-    void decRefAndDestroy();    //< Destroys caption object if the last reference was decremented.
-
-    /** Remove from current list and close gap.
-
-        Usually there are only very few instances, so maintaining a doubly
-        linked list isn't worth memory/performance wise and a simple walk does
-        it.
-     */
-    void removeFromList();
-
-    /** Replace this instance with pNew in a list, if any.
-
-        Used by move-ctor and move assignment operator.
-     */
-    void replaceInList(ScCaptionPtr* pNew) noexcept;
-
-    /** Dissolve list when the caption object is released or gone. */
-    void dissolve();
-
-    /** Just clear everything, while dissolving the list. */
-    void clear();
-};
-
 /** Internal data for a cell annotation. */
 struct ScNoteData
 {
@@ -148,7 +45,7 @@ struct ScNoteData
     OUString     maDate;             /// Creation date of the note.
     OUString     maAuthor;           /// Author of the note.
     ScCaptionInitDataRef mxInitData;        /// Initial data for invisible notes without SdrObject.
-    ScCaptionPtr        mxCaption;          /// Drawing object representing the cell note.
+    rtl::Reference<SdrCaptionObj> mxCaption;          /// Drawing object representing the cell note.
     bool                mbShown;            /// True = note is visible.
 
     explicit            ScNoteData( bool bShown = false );
@@ -282,7 +179,7 @@ class SC_DLLPUBLIC ScNoteUtil
 public:
 
     /** Creates and returns a caption object for a temporary caption. */
-    static ScCaptionPtr CreateTempCaption( ScDocument& rDoc, const ScAddress& rPos,
+    static rtl::Reference<SdrCaptionObj> CreateTempCaption( ScDocument& rDoc, const ScAddress& rPos,
                             SdrPage& rDrawPage, std::u16string_view rUserText,
                             const tools::Rectangle& rVisRect, bool bTailFront );