include/wx/persist.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/persist.h
   3 // Purpose:     common classes for persistence support
   4 // Author:      Vadim Zeitlin
   5 // Created:     2009-01-18
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 2009 Vadim Zeitlin <vadim@wxwidgets.org>
   8 // Licence:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef _WX_PERSIST_H_
  12 #define _WX_PERSIST_H_
  13
  14 #include "wx/string.h"
  15 #include "wx/hashmap.h"
  16 #include "wx/confbase.h"
  17
  18 class wxPersistentObject;
  19
  20 WX_DECLARE_VOIDPTR_HASH_MAP(wxPersistentObject *, wxPersistentObjectsMap);
  21
  22 // ----------------------------------------------------------------------------
  23 // global functions
  24 // ----------------------------------------------------------------------------
  25
  26 /*
  27    We do _not_ declare this function as doing this would force us to specialize
  28    it for the user classes deriving from the standard persistent classes.
  29    However we do define overloads of wxCreatePersistentObject() for all the wx
  30    classes which means that template wxPersistentObject::Restore() picks up the
  31    right overload to use provided that the header defining the correct overload
  32    is included before calling it. And a compilation error happens if this is
  33    not done.
  34
  35 template <class T>
  36 wxPersistentObject *wxCreatePersistentObject(T *obj);
  37
  38  */
  39
  40 // ----------------------------------------------------------------------------
  41 // wxPersistenceManager: global aspects of persistent windows
  42 // ----------------------------------------------------------------------------
  43
  44 class WXDLLIMPEXP_CORE wxPersistenceManager
  45 {
  46 public:
  47     // accessor to the unique persistence manager object
  48     static wxPersistenceManager& Get();
  49
  50     // trivial but virtual dtor
  51     //
  52     // FIXME-VC6: this only needs to be public because of VC6 bug
  53     virtual ~wxPersistenceManager();
  54
  55
  56     // globally disable restoring or saving the persistent properties (both are
  57     // enabled by default)
  58     void DisableSaving() { m_doSave = false; }
  59     void DisableRestoring() { m_doRestore = false; }
  60
  61
  62     // register an object with the manager: when using the first overload,
  63     // wxCreatePersistentObject() must be specialized for this object class;
  64     // with the second one the persistent adapter is created by the caller
  65     //
  66     // the object shouldn't be already registered with us
  67     template <class T>
  68     wxPersistentObject *Register(T *obj)
  69     {
  70         return Register(obj, wxCreatePersistentObject(obj));
  71     }
  72
  73     wxPersistentObject *Register(void *obj, wxPersistentObject *po);
  74
  75     // check if the object is registered and return the associated
  76     // wxPersistentObject if it is or NULL otherwise
  77     wxPersistentObject *Find(void *obj) const;
  78
  79     // unregister the object, this is called by wxPersistentObject itself so
  80     // there is usually no need to do it explicitly
  81     //
  82     // deletes the associated wxPersistentObject
  83     void Unregister(void *obj);
  84
  85
  86     // save/restore the state of an object
  87     //
  88     // these methods do nothing if DisableSaving/Restoring() was called
  89     //
  90     // Restore() returns true if the object state was really restored
  91     void Save(void *obj);
  92     bool Restore(void *obj);
  93
  94     // combines both Save() and Unregister() calls
  95     void SaveAndUnregister(void *obj)
  96     {
  97         Save(obj);
  98         Unregister(obj);
  99     }
 100
 101     // combines both Register() and Restore() calls
 102     template <class T>
 103     bool RegisterAndRestore(T *obj)
 104     {
 105         return Register(obj) && Restore(obj);
 106     }
 107
 108     bool RegisterAndRestore(void *obj, wxPersistentObject *po)
 109     {
 110         return Register(obj, po) && Restore(obj);
 111     }
 112
 113
 114     // methods used by the persistent objects to save and restore the data
 115     //
 116     // currently these methods simply use wxConfig::Get() but they may be
 117     // overridden in the derived class (once we allow creating custom
 118     // persistent managers)
 119 #define wxPERSIST_DECLARE_SAVE_RESTORE_FOR(Type)                              \
 120     virtual bool SaveValue(const wxPersistentObject& who,                     \
 121                            const wxString& name,                              \
 122                            Type value);                                       \
 123                                                                               \
 124     virtual bool                                                              \
 125     RestoreValue(const wxPersistentObject& who,                               \
 126                  const wxString& name,                                        \
 127                  Type *value)
 128
 129     wxPERSIST_DECLARE_SAVE_RESTORE_FOR(bool);
 130     wxPERSIST_DECLARE_SAVE_RESTORE_FOR(int);
 131     wxPERSIST_DECLARE_SAVE_RESTORE_FOR(long);
 132     wxPERSIST_DECLARE_SAVE_RESTORE_FOR(wxString);
 133
 134 #undef wxPERSIST_DECLARE_SAVE_RESTORE_FOR
 135
 136 private:
 137     // ctor is private, use Get()
 138     wxPersistenceManager()
 139     {
 140         m_doSave =
 141         m_doRestore = true;
 142     }
 143
 144
 145     // helpers of Save/Restore()
 146     //
 147     // TODO: make this customizable by allowing
 148     //          (a) specifying custom wxConfig object to use
 149     //          (b) allowing to use something else entirely
 150     wxConfigBase *GetConfig() const { return wxConfigBase::Get(); }
 151     wxString GetKey(const wxPersistentObject& who, const wxString& name) const;
 152
 153
 154     // map with the registered objects as keys and associated
 155     // wxPersistentObjects as values
 156     wxPersistentObjectsMap m_persistentObjects;
 157
 158     // true if we should restore/save the settings (it doesn't make much sense
 159     // to use this class when both of them are false but setting one of them to
 160     // false may make sense in some situations)
 161     bool m_doSave,
 162          m_doRestore;
 163
 164     wxDECLARE_NO_COPY_CLASS(wxPersistenceManager);
 165 };
 166
 167 // ----------------------------------------------------------------------------
 168 // wxPersistentObject: ABC for anything persistent
 169 // ----------------------------------------------------------------------------
 170
 171 class wxPersistentObject
 172 {
 173 public:
 174     // ctor associates us with the object whose options we save/restore
 175     wxPersistentObject(void *obj) : m_obj(obj) { }
 176
 177     // trivial but virtual dtor
 178     virtual ~wxPersistentObject() { }
 179
 180
 181     // methods used by wxPersistenceManager
 182     // ------------------------------------
 183
 184     // save/restore the corresponding objects settings
 185     //
 186     // these methods shouldn't be used directly as they don't respect the
 187     // global wxPersistenceManager::DisableSaving/Restoring() settings, use
 188     // wxPersistenceManager methods with the same name instead
 189     virtual void Save() const = 0;
 190     virtual bool Restore() = 0;
 191
 192
 193     // get the kind of the objects we correspond to, e.g. "Frame"
 194     virtual wxString GetKind() const = 0;
 195
 196     // get the name of the object we correspond to, e.g. "Main"
 197     virtual wxString GetName() const = 0;
 198
 199
 200     // return the associated object
 201     void *GetObject() const { return m_obj; }
 202
 203 protected:
 204     // wrappers for wxPersistenceManager methods which don't require passing
 205     // "this" as the first parameter all the time
 206     template <typename T>
 207     bool SaveValue(const wxString& name, T value) const
 208     {
 209         return wxPersistenceManager::Get().SaveValue(*this, name, value);
 210     }
 211
 212     template <typename T>
 213     bool RestoreValue(const wxString& name, T *value)
 214     {
 215         return wxPersistenceManager::Get().RestoreValue(*this, name, value);
 216     }
 217
 218 private:
 219     void * const m_obj;
 220
 221     wxDECLARE_NO_COPY_CLASS(wxPersistentObject);
 222 };
 223
 224 // FIXME-VC6: VC6 has troubles with template methods of DLL-exported classes,
 225 //            apparently it believes they should be defined in the DLL (which
 226 //            is, of course, impossible as the DLL doesn't know for which types
 227 //            will they be instantiated) instead of compiling them when
 228 //            building the main application itself. Because of this problem
 229 //            (which only arises in debug build!) we can't use the usual
 230 //            RegisterAndRestore(obj) with it and need to explicitly create the
 231 //            persistence adapter. To hide this ugliness we define a global
 232 //            function which does it for us.
 233 template <typename T>
 234 inline bool wxPersistentRegisterAndRestore(T *obj)
 235 {
 236     wxPersistentObject * const pers = wxCreatePersistentObject(obj);
 237
 238     return wxPersistenceManager::Get().RegisterAndRestore(obj, pers);
 239
 240 }
 241
 242 #endif // _WX_PERSIST_H_
 243