interface/wx/config.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        config.h
   3 // Purpose:     interface of wxConfigBase
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows licence
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxConfigBase
  11
  12     wxConfigBase defines the basic interface of all config classes. It cannot
  13     be used by itself (it is an abstract base class) and you will always use
  14     one of its derivations: wxFileConfig, wxRegConfig or any other.
  15
  16     However, usually you don't even need to know the precise nature of the
  17     class you're working with but you would just use the wxConfigBase methods.
  18     This allows you to write the same code regardless of whether you're working
  19     with the registry under Windows or text-based config files under Unix.
  20     To make writing the portable code even easier, wxWidgets provides a typedef
  21     wxConfig which is mapped onto the native wxConfigBase implementation on the
  22     given platform: i.e. wxRegConfig under Windows and wxFileConfig otherwise.
  23
  24     See @ref overview_config for a description of all features of this class.
  25
  26     It is highly recommended to use static functions Get() and/or Set(), so
  27     please have a look at them.
  28
  29     Related Include Files:
  30
  31     @li @c <wx/config.h>   - Let wxWidgets choose a wxConfig class for your
  32                              platform.
  33     @li @c <wx/confbase.h> - Base config class.
  34     @li @c <wx/fileconf.h> - wxFileConfig class.
  35     @li @c <wx/msw/regconf.h> - wxRegConfig class, see also wxRegKey.
  36
  37
  38     @section configbase_example Example
  39
  40     Here is how you would typically use this class:
  41
  42     @code
  43     // using wxConfig instead of writing wxFileConfig or wxRegConfig enhances
  44     // portability of the code
  45     wxConfig *config = new wxConfig("MyAppName");
  46
  47     wxString str;
  48     if ( config->Read("LastPrompt", &str) ) {
  49         // last prompt was found in the config file/registry and its value is
  50         // now in str
  51         // ...
  52     }
  53     else {
  54         // no last prompt...
  55     }
  56
  57     // another example: using default values and the full path instead of just
  58     // key name: if the key is not found , the value 17 is returned
  59     long value = config->ReadLong("/LastRun/CalculatedValues/MaxValue", 17);
  60
  61     // at the end of the program we would save everything back
  62     config->Write("LastPrompt", str);
  63     config->Write("/LastRun/CalculatedValues/MaxValue", value);
  64
  65     // the changes will be written back automatically
  66     delete config;
  67     @endcode
  68
  69     This basic example, of course, doesn't show all wxConfig features, such as
  70     enumerating, testing for existence and deleting the entries and groups of
  71     entries in the config file, its abilities to automatically store the
  72     default values or expand the environment variables on the fly. However, the
  73     main idea is that using this class is easy and that it should normally do
  74     what you expect it to.
  75
  76     @note In the documentation of this class, the words "config file" also mean
  77           "registry hive" for wxRegConfig and, generally speaking, might mean
  78           any physical storage where a wxConfigBase-derived class stores its
  79           data.
  80
  81
  82     @section configbase_static Static Functions
  83
  84     The static functions provided deal with the "default" config object.
  85     Although its usage is not at all mandatory it may be convenient to use a
  86     global config object instead of creating and deleting the local config
  87     objects each time you need one (especially because creating a wxFileConfig
  88     object might be a time consuming operation). In this case, you may create
  89     this global config object in the very start of the program and Set() it as
  90     the default. Then, from anywhere in your program, you may access it using
  91     the Get() function. This global wxConfig object will be deleted by
  92     wxWidgets automatically if it exists. Note that this implies that if you do
  93     delete this object yourself (usually in wxApp::OnExit()) you must use
  94     Set(@NULL) to prevent wxWidgets from deleting it the second time.
  95
  96     As it happens, you may even further simplify the procedure described above:
  97     you may forget about calling Set(). When Get() is called and there is no
  98     current object, it will create one using Create() function. To disable this
  99     behaviour DontCreateOnDemand() is provided.
 100
 101     @note You should use either Set() or Get() because wxWidgets library itself
 102           would take advantage of it and could save various information in it.
 103           For example wxFontMapper or Unix version of wxFileDialog have the
 104           ability to use wxConfig class.
 105
 106
 107     @section configbase_paths Path Management
 108
 109     As explained in the @ref overview_config "config overview", the config
 110     classes support a file system-like hierarchy of keys (files) and groups
 111     (directories). As in the file system case, to specify a key in the config
 112     class you must use a path to it. Config classes also support the notion of
 113     the current group, which makes it possible to use the relative paths. To
 114     clarify all this, here is an example (it is only for the sake of
 115     demonstration, it doesn't do anything sensible!):
 116
 117     @code
 118     wxConfig *config = new wxConfig("FooBarApp");
 119
 120     // right now the current path is '/'
 121     conf->Write("RootEntry", 1);
 122
 123     // go to some other place: if the group(s) don't exist, they will be created
 124     conf->SetPath("/Group/Subgroup");
 125
 126     // create an entry in subgroup
 127     conf->Write("SubgroupEntry", 3);
 128
 129     // '..' is understood
 130     conf->Write("../GroupEntry", 2);
 131     conf->SetPath("..");
 132
 133     wxASSERT( conf->ReadLong("Subgroup/SubgroupEntry", 0) == 3 );
 134
 135     // use absolute path: it is allowed, too
 136     wxASSERT( conf->ReadLong("/RootEntry", 0) == 1 );
 137     @endcode
 138
 139     It is highly recommended that you restore the path to its old value on
 140     function exit:
 141
 142     @code
 143     void foo(wxConfigBase *config)
 144     {
 145         wxString strOldPath = config->GetPath();
 146
 147         config->SetPath("/Foo/Data");
 148         // ...
 149
 150         config->SetPath(strOldPath);
 151     }
 152     @endcode
 153
 154     Otherwise the assert in the following example will surely fail (we suppose
 155     here that the foo() function is the same as above except that it doesn’t
 156     save and restore the path):
 157
 158     @code
 159     void bar(wxConfigBase *config)
 160     {
 161         config->Write("Test", 17);
 162
 163         foo(config);
 164
 165         // we're reading "/Foo/Data/Test" here! -1 will probably be returned...
 166         wxASSERT( config->ReadLong("Test", -1) == 17 );
 167     }
 168     @endcode
 169
 170     Finally, the path separator in wxConfigBase and derived classes is always
 171     "/", regardless of the platform (i.e. it is not "\\" under Windows).
 172
 173
 174     @section configbase_enumeration Enumeration
 175
 176     The enumeration functions allow you to enumerate all entries and groups in
 177     the config file. All functions here return @false when there are no more
 178     items.
 179
 180     You must pass the same index to GetNext() and GetFirst() (don't modify it).
 181     Please note that it is not the index of the current item (you will have
 182     some great surprises with wxRegConfig if you assume this) and you shouldn't
 183     even look at it: it is just a "cookie" which stores the state of the
 184     enumeration. It can't be stored inside the class because it would prevent
 185     you from running several enumerations simultaneously, that's why you must
 186     pass it explicitly.
 187
 188     Having said all this, enumerating the config entries/groups is very simple:
 189
 190     @code
 191     wxConfigBase *config = ...;
 192     wxArrayString aNames;
 193
 194     // enumeration variables
 195     wxString str;
 196     long dummy;
 197
 198     // first enum all entries
 199     bool bCont = config->GetFirstEntry(str, dummy);
 200     while ( bCont ) {
 201         aNames.Add(str);
 202
 203         bCont = GetConfig()->GetNextEntry(str, dummy);
 204     }
 205
 206     // ... we have all entry names in aNames...
 207
 208     // now all groups...
 209     bCont = GetConfig()->GetFirstGroup(str, dummy);
 210     while ( bCont ) {
 211         aNames.Add(str);
 212
 213         bCont = GetConfig()->GetNextGroup(str, dummy);
 214     }
 215
 216     // ... we have all group (and entry) names in aNames...
 217     @endcode
 218
 219     There are also functions to get the number of entries/subgroups without
 220     actually enumerating them, but you will probably never need them.
 221
 222
 223     @section configbase_keyaccess Key Access
 224
 225     The key access functions are the core of wxConfigBase class: they allow you
 226     to read and write config file data. All Read() functions take a default
 227     value which will be returned if the specified key is not found in the
 228     config file.
 229
 230     Currently, supported types of data are: wxString, @c long, @c double,
 231     @c bool, wxColour and any other types for which the functions
 232     wxToString() and wxFromString() are defined.
 233
 234     Try not to read long values into string variables and vice versa:
 235     although it just might work with wxFileConfig, you will get a system
 236     error with wxRegConfig because in the Windows registry the different
 237     types of entries are indeed used.
 238
 239     Final remark: the @a szKey parameter for all these functions can
 240     contain an arbitrary path (either relative or absolute), not just the
 241     key name.
 242
 243     @beginWxPythonOnly
 244     In place of a single overloaded method name, wxPython implements the
 245     following methods:
 246     - Read(key, default="") - Returns a string.
 247     - ReadInt(key, default=0) - Returns an integer.
 248     - ReadFloat(key, default=0.0) - Returns a floating point number.
 249     - ReadBool(key, default=0) - Returns a boolean.
 250     - Write(key, value) - Writes a string.
 251     - WriteInt(key, value) - Writes an int.
 252     - WriteFloat(key, value) - Writes a floating point number.
 253     @endWxPythonOnly
 254
 255
 256     @library{wxbase}
 257     @category{cfg}
 258 */
 259 class wxConfigBase : public wxObject
 260 {
 261 public:
 262     /**
 263         This is the default and only constructor of the wxConfigBase class, and
 264         derived classes.
 265
 266         @param appName
 267             The application name. If this is empty, the class will normally use
 268             wxApp::GetAppName() to set it. The application name is used in the
 269             registry key on Windows, and can be used to deduce the local
 270             filename parameter if that is missing.
 271         @param vendorName
 272             The vendor name. If this is empty, it is assumed that no vendor
 273             name is wanted, if this is optional for the current config class.
 274             The vendor name is appended to the application name for
 275             wxRegConfig.
 276         @param localFilename
 277             Some config classes require a local filename. If this is not
 278             present, but required, the application name will be used instead.
 279         @param globalFilename
 280             Some config classes require a global filename. If this is not
 281             present, but required, the application name will be used instead.
 282         @param style
 283             Can be one of @c wxCONFIG_USE_LOCAL_FILE and @c wxCONFIG_USE_GLOBAL_FILE.
 284             @n The style interpretation depends on the config class and is ignored
 285             by some implementations. For wxFileConfig, these styles determine
 286             whether a local or global config file is created or used: if
 287             @c wxCONFIG_USE_GLOBAL_FILE is used, then settings are read from the
 288             global config file and if @c wxCONFIG_USE_LOCAL_FILE is used, settings
 289             are read from and written to local config file (if they are both
 290             set, global file is read first, then local file, overwriting global
 291             settings). If the flag is present but the parameter is empty, the
 292             parameter will be set to a default. If the parameter is present but
 293             the style flag not, the relevant flag will be added to the style.
 294             For wxRegConfig, the GLOBAL flag refers to the @c HKLM key while LOCAL
 295             one is for the usual @c HKCU one.
 296             @n For wxFileConfig you can also add @c wxCONFIG_USE_RELATIVE_PATH by
 297             logically or'ing it to either of the _FILE options to tell
 298             wxFileConfig to use relative instead of absolute paths.
 299             @n On non-VMS Unix systems, the default local configuration file is
 300             "~/.appname". However, this path may be also used as user data
 301             directory (see wxStandardPaths::GetUserDataDir()) if the
 302             application has several data files. In this case
 303             @c wxCONFIG_USE_SUBDIR flag, which changes the default local
 304             configuration file to "~/.appname/appname" should be used. Notice
 305             that this flag is ignored if @a localFilename is provided.
 306             @c wxCONFIG_USE_SUBDIR is new since wxWidgets version 2.8.2.
 307             @n For wxFileConfig, you can also add
 308             @c wxCONFIG_USE_NO_ESCAPE_CHARACTERS which will turn off character
 309             escaping for the values of entries stored in the config file: for
 310             example a foo key with some backslash characters will be stored as
 311             "foo=C:\mydir" instead of the usual storage of "foo=C:\\mydir".
 312             @n The @c wxCONFIG_USE_NO_ESCAPE_CHARACTERS style can be helpful if your
 313             config file must be read or written to by a non-wxWidgets program
 314             (which might not understand the escape characters). Note, however,
 315             that if @c wxCONFIG_USE_NO_ESCAPE_CHARACTERS style is used, it is is
 316             now your application's responsibility to ensure that there is no
 317             newline or other illegal characters in a value, before writing that
 318             value to the file.
 319         @param conv
 320             This parameter is only used by wxFileConfig when compiled in
 321             Unicode mode. It specifies the encoding in which the configuration
 322             file is written.
 323
 324         @remarks By default, environment variable expansion is on and recording
 325                  defaults is off.
 326     */
 327     wxConfigBase(const wxString& appName = wxEmptyString,
 328                  const wxString& vendorName = wxEmptyString,
 329                  const wxString& localFilename = wxEmptyString,
 330                  const wxString& globalFilename = wxEmptyString,
 331                  long style = 0,
 332                  const wxMBConv& conv = wxConvAuto());
 333
 334     /**
 335         Empty but ensures that dtor of all derived classes is virtual.
 336     */
 337     virtual ~wxConfigBase();
 338
 339
 340     /**
 341         @name Path Management
 342
 343         See @ref configbase_paths
 344     */
 345     //@{
 346
 347     /**
 348         Retrieve the current path (always as absolute path).
 349     */
 350     virtual const wxString& GetPath() const = 0;
 351
 352     /**
 353         Set current path: if the first character is '/', it is the absolute
 354         path, otherwise it is a relative path. '..' is supported. If @a strPath
 355         doesn't exist it is created.
 356     */
 357     virtual void SetPath(const wxString& strPath) = 0;
 358
 359     //@}
 360
 361
 362     /**
 363         @name Enumeration
 364
 365         See @ref configbase_enumeration
 366     */
 367     //@{
 368
 369     /**
 370         Gets the first entry.
 371
 372         @beginWxPythonOnly
 373         The wxPython version of this method returns a 3-tuple consisting of the
 374         continue flag, the value string, and the index for the next call.
 375         @endWxPythonOnly
 376
 377         @beginWxPerlOnly
 378         In wxPerl this method takes no parameters and returns a 3-element
 379         list (continue_flag, string, index_for_getnextentry).
 380         @endWxPerlOnly
 381     */
 382     virtual bool GetFirstEntry(wxString& str, long& index) const = 0;
 383
 384     /**
 385         Gets the first group.
 386
 387         @beginWxPythonOnly
 388         The wxPython version of this method returns a 3-tuple consisting of the
 389         continue flag, the value string, and the index for the next call.
 390         @endWxPythonOnly
 391
 392         @beginWxPerlOnly
 393         In wxPerl this method takes no parameters and returns a 3-element
 394         list (continue_flag, string, index_for_getnextentry).
 395         @endWxPerlOnly
 396     */
 397     virtual bool GetFirstGroup(wxString& str, long& index) const = 0;
 398
 399     /**
 400         Gets the next entry.
 401
 402         @beginWxPythonOnly
 403         The wxPython version of this method returns a 3-tuple consisting of the
 404         continue flag, the value string, and the index for the next call.
 405         @endWxPythonOnly
 406
 407         @beginWxPerlOnly
 408         In wxPerl this method only takes the @a index parameter and
 409         returns a 3-element list (continue_flag, string,
 410         index_for_getnextentry).
 411         @endWxPerlOnly
 412     */
 413     virtual bool GetNextEntry(wxString& str, long& index) const = 0;
 414
 415     /**
 416         Gets the next group.
 417
 418         @beginWxPythonOnly
 419         The wxPython version of this method returns a 3-tuple consisting of the
 420         continue flag, the value string, and the index for the next call.
 421         @endWxPythonOnly
 422
 423         @beginWxPerlOnly
 424         In wxPerl this method only takes the @a index parameter and
 425         returns a 3-element list (continue_flag, string,
 426         index_for_getnextentry).
 427         @endWxPerlOnly
 428     */
 429     virtual bool GetNextGroup(wxString& str, long& index) const = 0;
 430
 431     /**
 432         Get number of entries in the current group.
 433     */
 434     virtual size_t GetNumberOfEntries(bool bRecursive = false) const = 0;
 435
 436     /**
 437         Get number of entries/subgroups in the current group, with or without
 438         its subgroups.
 439     */
 440     virtual size_t GetNumberOfGroups(bool bRecursive = false) const = 0;
 441
 442     //@}
 443
 444
 445     enum EntryType
 446     {
 447         Type_Unknown,
 448         Type_String,
 449         Type_Boolean,
 450         Type_Integer,
 451         Type_Float
 452     };
 453
 454     /**
 455         @name Tests of Existence
 456     */
 457     //@{
 458
 459     /**
 460         @return @true if either a group or an entry with a given name exists.
 461     */
 462     bool Exists(const wxString& strName) const;
 463
 464     /**
 465         Returns the type of the given entry or @e Unknown if the entry doesn't
 466         exist. This function should be used to decide which version of Read()
 467         should be used because some of wxConfig implementations will complain
 468         about type mismatch otherwise: e.g., an attempt to read a string value
 469         from an integer key with wxRegConfig will fail.
 470     */
 471     virtual wxConfigBase::EntryType GetEntryType(const wxString& name) const;
 472
 473     /**
 474         @return @true if the entry by this name exists.
 475     */
 476     virtual bool HasEntry(const wxString& strName) const = 0;
 477
 478     /**
 479         @return @true if the group by this name exists.
 480     */
 481     virtual bool HasGroup(const wxString& strName) const = 0;
 482
 483     //@}
 484
 485
 486     /**
 487         @name Miscellaneous Functions
 488     */
 489     //@{
 490
 491     /**
 492         Returns the application name.
 493     */
 494     wxString GetAppName() const;
 495
 496     /**
 497         Returns the vendor name.
 498     */
 499     wxString GetVendorName() const;
 500
 501     //@}
 502
 503
 504     /**
 505         @name Key Access
 506
 507         See @ref configbase_keyaccess
 508     */
 509     //@{
 510
 511     /**
 512         Permanently writes all changes (otherwise, they're only written from
 513         object's destructor).
 514     */
 515     virtual bool Flush(bool bCurrentOnly = false) = 0;
 516
 517     /**
 518         Read a string from the key, returning @true if the value was read. If
 519         the key was not found, @a str is not changed.
 520
 521         @beginWxPerlOnly
 522         Not supported by wxPerl.
 523         @endWxPerlOnly
 524     */
 525     bool Read(const wxString& key, wxString* str) const;
 526     /**
 527         Read a string from the key. The default value is returned if the key
 528         was not found.
 529
 530         @return @true if value was really read, @false if the default was used.
 531
 532         @beginWxPerlOnly
 533         Not supported by wxPerl.
 534         @endWxPerlOnly
 535     */
 536     bool Read(const wxString& key, wxString* str,
 537               const wxString& defaultVal) const;
 538     /**
 539         Another version of Read(), returning the string value directly.
 540
 541         @beginWxPerlOnly
 542         In wxPerl, this can be called as:
 543         - Read(key): returns the empty string if no key is found
 544         - Read(key, default): returns the default value if no key is found
 545         @endWxPerlOnly
 546     */
 547     const wxString Read(const wxString& key,
 548                         const wxString& defaultVal) const;
 549     /**
 550         Reads a long value, returning @true if the value was found. If the
 551         value was not found, @a l is not changed.
 552
 553         @beginWxPerlOnly
 554         Not supported by wxPerl.
 555         @endWxPerlOnly
 556     */
 557     bool Read(const wxString& key, long* l) const;
 558     /**
 559         Reads a long value, returning @true if the value was found. If the
 560         value was not found, @a defaultVal is used instead.
 561
 562         @beginWxPerlOnly
 563         In wxPerl, this can be called as:
 564         - ReadInt(key): returns the 0 if no key is found
 565         - ReadInt(key, default): returns the default value if no key is found
 566         @endWxPerlOnly
 567     */
 568     bool Read(const wxString& key, long* l,
 569               long defaultVal) const;
 570     /**
 571         Reads a double value, returning @true if the value was found. If the
 572         value was not found, @a d is not changed.
 573
 574         @beginWxPerlOnly
 575         Not supported by wxPerl.
 576         @endWxPerlOnly
 577     */
 578     bool Read(const wxString& key, double* d) const;
 579     /**
 580         Reads a double value, returning @true if the value was found. If the
 581         value was not found, @a defaultVal is used instead.
 582
 583         @beginWxPerlOnly
 584         In wxPerl, this can be called as:
 585         - ReadFloat(key): returns the 0.0 if no key is found
 586         - ReadFloat(key, default): returns the default value if no key is found
 587         @endWxPerlOnly
 588     */
 589     bool Read(const wxString& key, double* d,
 590                      double defaultVal) const;
 591
 592     /**
 593         Reads a float value, returning @true if the value was found.
 594
 595         With the second overload, if the value was not found, @a defaultVal is
 596         used instead.
 597
 598         Notice that the value is read as a double but must be in a valid range
 599         for floats for the function to return @true.
 600
 601         @since 2.9.1
 602
 603         @beginWxPerlOnly
 604         Not supported by wxPerl.
 605         @endWxPerlOnly
 606     */
 607     //@{
 608     bool Read(const wxString& key, float* f) const;
 609     bool Read(const wxString& key, float* f, float defaultVal) const;
 610     //@}
 611
 612     /**
 613         Reads a float value, returning @true if the value was found. If the
 614         value was not found, @a b is not changed.
 615
 616         @since 2.9.1
 617
 618         @beginWxPerlOnly
 619         Not supported by wxPerl.
 620         @endWxPerlOnly
 621     */
 622     bool Read(const wxString& key, bool* b) const;
 623     /**
 624         Reads a bool value, returning @true if the value was found. If the
 625         value was not found, @a defaultVal is used instead.
 626
 627         @beginWxPerlOnly
 628         In wxPerl, this can be called as:
 629         - ReadBool(key): returns false if no key is found
 630         - ReadBool(key, default): returns the default value if no key is found
 631         @endWxPerlOnly
 632     */
 633     bool Read(const wxString& key, bool* d,
 634               bool defaultVal) const;
 635     /**
 636         Reads a binary block, returning @true if the value was found. If the
 637         value was not found, @a buf is not changed.
 638     */
 639     bool Read(const wxString& key, wxMemoryBuffer* buf) const;
 640     /**
 641         Reads a value of type T, for which function wxFromString() is defined,
 642         returning @true if the value was found. If the value was not found,
 643         @a value is not changed.
 644     */
 645     bool Read(const wxString& key, T* value) const;
 646     /**
 647         Reads a value of type T, for which function wxFromString() is defined,
 648         returning @true if the value was found. If the value was not found,
 649         @a defaultVal is used instead.
 650     */
 651     bool Read(const wxString& key, T* value,
 652               const T& defaultVal) const;
 653
 654     /**
 655         Reads a bool value from the key and returns it. @a defaultVal is
 656         returned if the key is not found.
 657     */
 658     bool ReadBool(const wxString& key, bool defaultVal) const;
 659
 660     /**
 661         Reads a double value from the key and returns it. @a defaultVal is
 662         returned if the key is not found.
 663     */
 664     double ReadDouble(const wxString& key, double defaultVal) const;
 665
 666     /**
 667         Reads a long value from the key and returns it. @a defaultVal is
 668         returned if the key is not found.
 669     */
 670     long ReadLong(const wxString& key, long defaultVal) const;
 671
 672     /**
 673         Reads a value of type T (for which the function wxFromString() must be
 674         defined) from the key and returns it. @a defaultVal is returned if the
 675         key is not found.
 676     */
 677     T ReadObject(const wxString& key, T const& defaultVal) const;
 678
 679     /**
 680         Writes the wxString value to the config file and returns @true on
 681         success.
 682     */
 683     bool Write(const wxString& key, const wxString& value);
 684     /**
 685         Writes the long value to the config file and returns @true on success.
 686     */
 687     bool Write(const wxString& key, long value);
 688     /**
 689         Writes the double value to the config file and returns @true on
 690         success.
 691
 692         Notice that if floating point numbers are saved as strings (as is the
 693         case with the configuration files used by wxFileConfig), this function
 694         uses the C locale for writing out the number, i.e. it will always use a
 695         period as the decimal separator, irrespectively of the current locale.
 696         This behaviour is new since wxWidgets 2.9.1 as the current locale was
 697         used before, but the change should be transparent because both C and
 698         current locales are tried when reading the numbers back.
 699     */
 700     bool Write(const wxString& key, double value);
 701     /**
 702         Writes the bool value to the config file and returns @true on success.
 703     */
 704     bool Write(const wxString& key, bool value);
 705     /**
 706         Writes the wxMemoryBuffer value to the config file and returns @true on
 707         success.
 708     */
 709     bool Write(const wxString& key, const wxMemoryBuffer& buf);
 710     /**
 711         Writes the specified value to the config file and returns @true on
 712         success. The function wxToString() must be defined for type @e T.
 713     */
 714     bool Write(const wxString& key, T const& buf);
 715
 716     //@}
 717
 718
 719     /**
 720         @name Rename Entries/Groups
 721
 722         These functions allow renaming entries or subgroups of the current
 723         group. They will return @false on error, typically because either the
 724         entry/group with the original name doesn't exist, because the
 725         entry/group with the new name already exists or because the function is
 726         not supported in this wxConfig implementation.
 727     */
 728     //@{
 729
 730     /**
 731         Renames an entry in the current group. The entries names (both the old
 732         and the new one) shouldn't contain backslashes, i.e. only simple names
 733         and not arbitrary paths are accepted by this function.
 734
 735         @return @false if @a oldName doesn't exist or if @a newName already
 736                 exists.
 737     */
 738     virtual bool RenameEntry(const wxString& oldName,
 739                              const wxString& newName) = 0;
 740
 741     /**
 742         Renames a subgroup of the current group. The subgroup names (both the
 743         old and the new one) shouldn't contain backslashes, i.e. only simple
 744         names and not arbitrary paths are accepted by this function.
 745
 746         @return @false if @a oldName doesn't exist or if @a newName already
 747                 exists.
 748     */
 749     virtual bool RenameGroup(const wxString& oldName,
 750                              const wxString& newName) = 0;
 751
 752     //@}
 753
 754
 755     /**
 756         @name Delete Entries/Groups
 757
 758         These functions delete entries and/or groups of entries from the config
 759         file. DeleteAll() is especially useful if you want to erase all traces
 760         of your program presence: for example, when you uninstall it.
 761     */
 762     //@{
 763
 764     /**
 765         Delete the whole underlying object (disk file, registry key, ...).
 766         Primarly for use by uninstallation routine.
 767     */
 768     virtual bool DeleteAll() = 0;
 769
 770     /**
 771         Deletes the specified entry and the group it belongs to if it was the
 772         last key in it and the second parameter is @true.
 773     */
 774     virtual bool DeleteEntry(const wxString& key,
 775                              bool bDeleteGroupIfEmpty = true) = 0;
 776
 777     /**
 778         Delete the group (with all subgroups). If the current path is under the
 779         group being deleted it is changed to its deepest still existing
 780         component. E.g. if the current path is @c "/A/B/C/D" and the group @c C
 781         is deleted, the path becomes @c "/A/B".
 782     */
 783     virtual bool DeleteGroup(const wxString& key) = 0;
 784
 785     //@}
 786
 787
 788     /**
 789         @name Options
 790
 791         Some aspects of wxConfigBase behaviour can be changed during run-time.
 792         The first of them is the expansion of environment variables in the
 793         string values read from the config file: for example, if you have the
 794         following in your config file:
 795
 796         @code
 797         # config file for my program
 798         UserData = $HOME/data
 799
 800         # the following syntax is valud only under Windows
 801         UserData = %windir%\\data.dat
 802         @endcode
 803
 804         The call to Read("UserData") will return something like
 805         @c "/home/zeitlin/data" on linux for example.
 806
 807         Although this feature is very useful, it may be annoying if you read a
 808         value which containts '$' or '%' symbols (% is used for environment
 809         variables expansion under Windows) which are not used for environment
 810         variable expansion. In this situation you may call
 811         SetExpandEnvVars(@false) just before reading this value and
 812         SetExpandEnvVars(@true) just after. Another solution would be to prefix
 813         the offending symbols with a backslash.
 814     */
 815     //@{
 816
 817     /**
 818         Returns @true if we are expanding environment variables in key values.
 819     */
 820     bool IsExpandingEnvVars() const;
 821
 822     /**
 823         Returns @true if we are writing defaults back to the config file.
 824     */
 825     bool IsRecordingDefaults() const;
 826
 827     /**
 828         Determine whether we wish to expand environment variables in key
 829         values.
 830     */
 831     void SetExpandEnvVars(bool bDoIt = true);
 832
 833     /**
 834         Sets whether defaults are recorded to the config file whenever an
 835         attempt to read the value which is not present in it is done.
 836
 837         If on (default is off) all default values for the settings used by the
 838         program are written back to the config file. This allows the user to
 839         see what config options may be changed and is probably useful only for
 840         wxFileConfig.
 841     */
 842     void SetRecordDefaults(bool bDoIt = true);
 843
 844     //@}
 845
 846
 847     /**
 848         Create a new config object and sets it as the current one.
 849
 850         This function will create the most appropriate implementation of
 851         wxConfig available for the current platform. By default this means that
 852         the system registry will be used for storing the configuration
 853         information under MSW and a file under the user home directory (see
 854         wxStandardPaths::GetUserConfigDir()) elsewhere.
 855
 856         If you prefer to use the configuration files everywhere, you can define
 857         @c wxUSE_CONFIG_NATIVE to 0 when compiling wxWidgets. Or you can simply
 858         always create wxFileConfig explicitly.
 859
 860         Finally, if you want to create a custom wxConfig subclass you may
 861         change this function behaviour by overriding wxAppTraits::CreateConfig()
 862         to create it. An example when this could be useful could be an
 863         application which could be installed either normally (in which case the
 864         default behaviour of using wxRegConfig is appropriate) or in a
 865         "portable" way in which case a wxFileConfig with a file in the program
 866         directory would be used and the choice would be done in CreateConfig()
 867         at run-time.
 868     */
 869     static wxConfigBase* Create();
 870
 871     /**
 872         Calling this function will prevent @e Get() from automatically creating
 873         a new config object if the current one is @NULL. It might be useful to
 874         call it near the program end to prevent "accidental" creation of a new
 875         config object.
 876     */
 877     static void DontCreateOnDemand();
 878
 879     /**
 880         Get the current config object. If there is no current object and
 881         @a CreateOnDemand is @true, this creates one (using Create()) unless
 882         DontCreateOnDemand() was called previously.
 883     */
 884     static wxConfigBase* Get(bool CreateOnDemand = true);
 885
 886     /**
 887         Sets the config object as the current one, returns the pointer to the
 888         previous current object (both the parameter and returned value may be
 889         @NULL).
 890     */
 891     static wxConfigBase* Set(wxConfigBase* pConfig);
 892 };
 893