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1 /////////////////////////////////////////////////////////////////////////////
3 // Purpose: interface of wxConfigBase
4 // Author: wxWidgets team
6 // Licence: wxWindows license
7 /////////////////////////////////////////////////////////////////////////////
12 wxConfigBase defines the basic interface of all config classes. It can not
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.
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 Win32 or text-based config files under Unix (or
20 even Windows 3.1 .INI files if you're really unlucky). To make writing the
21 portable code even easier, wxWidgets provides a typedef wxConfig which is
22 mapped onto the native wxConfigBase implementation on the given platform:
23 i.e. wxRegConfig under Win32 and wxFileConfig otherwise.
25 See @ref overview_config for a description of all features of this class.
27 It is highly recommended to use static functions Get() and/or Set(), so
28 please have a look at them.
30 Related Include Files:
32 @li @c <wx/config.h> - Let wxWidgets choose a wxConfig class for your
34 @li @c <wx/confbase.h> - Base config class.
35 @li @c <wx/fileconf.h> - wxFileConfig class.
36 @li @c <wx/msw/regconf.h> - wxRegConfig class, see also wxRegKey.
39 @section configbase_example Example
41 Here is how you would typically use this class:
44 // using wxConfig instead of writing wxFileConfig or wxRegConfig enhances
45 // portability of the code
46 wxConfig *config = new wxConfig("MyAppName");
49 if ( config->Read("LastPrompt", &str) ) {
50 // last prompt was found in the config file/registry and its value is
58 // another example: using default values and the full path instead of just
59 // key name: if the key is not found , the value 17 is returned
60 long value = config->ReadLong("/LastRun/CalculatedValues/MaxValue", 17);
62 // at the end of the program we would save everything back
63 config->Write("LastPrompt", str);
64 config->Write("/LastRun/CalculatedValues/MaxValue", value);
66 // the changes will be written back automatically
70 This basic example, of course, doesn't show all wxConfig features, such as
71 enumerating, testing for existence and deleting the entries and groups of
72 entries in the config file, its abilities to automatically store the
73 default values or expand the environment variables on the fly. However, the
74 main idea is that using this class is easy and that it should normally do
75 what you expect it to.
77 @note In the documentation of this class, the words "config file" also mean
78 "registry hive" for wxRegConfig and, generally speaking, might mean
79 any physical storage where a wxConfigBase-derived class stores its
83 @section configbase_static Static Functions
85 The static functions provided deal with the "default" config object.
86 Although its usage is not at all mandatory it may be convenient to use a
87 global config object instead of creating and deleting the local config
88 objects each time you need one (especially because creating a wxFileConfig
89 object might be a time consuming operation). In this case, you may create
90 this global config object in the very start of the program and Set() it as
91 the default. Then, from anywhere in your program, you may access it using
92 the Get() function. This global wxConfig object will be deleted by
93 wxWidgets automatically if it exists. Note that this implies that if you do
94 delete this object yourself (usually in wxApp::OnExit()) you must use
95 Set(@NULL) to prevent wxWidgets from deleting it the second time.
97 As it happens, you may even further simplify the procedure described above:
98 you may forget about calling Set(). When Get() is called and there is no
99 current object, it will create one using Create() function. To disable this
100 behaviour DontCreateOnDemand() is provided.
102 @note You should use either Set() or Get() because wxWidgets library itself
103 would take advantage of it and could save various information in it.
104 For example wxFontMapper or Unix version of wxFileDialog have the
105 ability to use wxConfig class.
108 @section configbase_paths Path Management
110 As explained in the @ref overview_config "config overview", the config
111 classes support a file system-like hierarchy of keys (files) and groups
112 (directories). As in the file system case, to specify a key in the config
113 class you must use a path to it. Config classes also support the notion of
114 the current group, which makes it possible to use the relative paths. To
115 clarify all this, here is an example (it is only for the sake of
116 demonstration, it doesn't do anything sensible!):
119 wxConfig *config = new wxConfig("FooBarApp");
121 // right now the current path is '/'
122 conf->Write("RootEntry", 1);
124 // go to some other place: if the group(s) don't exist, they will be created
125 conf->SetPath("/Group/Subgroup");
127 // create an entry in subgroup
128 conf->Write("SubgroupEntry", 3);
130 // '..' is understood
131 conf->Write("../GroupEntry", 2);
134 wxASSERT( conf->ReadLong("Subgroup/SubgroupEntry", 0) == 3 );
136 // use absolute path: it is allowed, too
137 wxASSERT( conf->ReadLong("/RootEntry", 0) == 1 );
140 It is highly recommended that you restore the path to its old value on
144 void foo(wxConfigBase *config)
146 wxString strOldPath = config->GetPath();
148 config->SetPath("/Foo/Data");
151 config->SetPath(strOldPath);
155 Otherwise the assert in the following example will surely fail (we suppose
156 here that the foo() function is the same as above except that it doesn’t
157 save and restore the path):
160 void bar(wxConfigBase *config)
162 config->Write("Test", 17);
166 // we're reading "/Foo/Data/Test" here! -1 will probably be returned...
167 wxASSERT( config->ReadLong("Test", -1) == 17 );
171 Finally, the path separator in wxConfigBase and derived classes is always
172 "/", regardless of the platform (i.e. it is not "\\" under Windows).
175 @section configbase_enumeration Enumeration
177 The enumeration functions allow you to enumerate all entries and groups in
178 the config file. All functions here return @false when there are no more
181 You must pass the same index to GetNext() and GetFirst() (don't modify it).
182 Please note that it is not the index of the current item (you will have
183 some great surprises with wxRegConfig if you assume this) and you shouldn't
184 even look at it: it is just a "cookie" which stores the state of the
185 enumeration. It can't be stored inside the class because it would prevent
186 you from running several enumerations simultaneously, that's why you must
189 Having said all this, enumerating the config entries/groups is very simple:
192 wxConfigBase *config = ...;
193 wxArrayString aNames;
195 // enumeration variables
199 // first enum all entries
200 bool bCont = config->GetFirstEntry(str, dummy);
204 bCont = GetConfig()->GetNextEntry(str, dummy);
207 // ... we have all entry names in aNames...
210 bCont = GetConfig()->GetFirstGroup(str, dummy);
214 bCont = GetConfig()->GetNextGroup(str, dummy);
217 // ... we have all group (and entry) names in aNames...
220 There are also functions to get the number of entries/subgroups without
221 actually enumerating them, but you will probably never need them.
224 @section configbase_keyaccess Key Access
226 The key access functions are the core of wxConfigBase class: they allow you
227 to read and write config file data. All Read() functions take a default
228 value which will be returned if the specified key is not found in the
231 Currently, supported types of data are: wxString, @c long, @c double,
232 @c bool, wxColour and any other types for which the functions
233 wxToString() and wxFromString() are defined.
235 Try not to read long values into string variables and vice versa:
236 although it just might work with wxFileConfig, you will get a system
237 error with wxRegConfig because in the Windows registry the different
238 types of entries are indeed used.
240 Final remark: the @a szKey parameter for all these functions can
241 contain an arbitrary path (either relative or absolute), not just the
245 In place of a single overloaded method name, wxPython implements the
247 - Read(key, default="") - Returns a string.
248 - ReadInt(key, default=0) - Returns an integer.
249 - ReadFloat(key, default=0.0) - Returns a floating point number.
250 - ReadBool(key, default=0) - Returns a boolean.
251 - Write(key, value) - Writes a string.
252 - WriteInt(key, value) - Writes an int.
253 - WriteFloat(key, value) - Writes a floating point number.
260 class wxConfigBase
: public wxObject
264 This is the default and only constructor of the wxConfigBase class, and
268 The application name. If this is empty, the class will normally use
269 wxApp::GetAppName() to set it. The application name is used in the
270 registry key on Windows, and can be used to deduce the local
271 filename parameter if that is missing.
273 The vendor name. If this is empty, it is assumed that no vendor
274 name is wanted, if this is optional for the current config class.
275 The vendor name is appended to the application name for
278 Some config classes require a local filename. If this is not
279 present, but required, the application name will be used instead.
280 @param globalFilename
281 Some config classes require a global filename. If this is not
282 present, but required, the application name will be used instead.
284 Can be one of wxCONFIG_USE_LOCAL_FILE and wxCONFIG_USE_GLOBAL_FILE.
285 The style interpretation depends on the config class and is ignored
286 by some implementations. For wxFileConfig, these styles determine
287 whether a local or global config file is created or used: if
288 wxCONFIG_USE_GLOBAL_FILE is used, then settings are read from the
289 global config file and if wxCONFIG_USE_LOCAL_FILE is used, settings
290 are read from and written to local config file (if they are both
291 set, global file is read first, then local file, overwriting global
292 settings). If the flag is present but the parameter is empty, the
293 parameter will be set to a default. If the parameter is present but
294 the style flag not, the relevant flag will be added to the style.
295 For wxRegConfig, thie GLOBAL flag refers to HKLM key while LOCAL
296 one is for the usual HKCU one.
297 @n For wxFileConfig you can also add wxCONFIG_USE_RELATIVE_PATH by
298 logically or'ing it to either of the _FILE options to tell
299 wxFileConfig to use relative instead of absolute paths.
300 @n On non-VMS Unix systems, the default local configuration file is
301 "~/.appname". However, this path may be also used as user data
302 directory (see wxStandardPaths::GetUserDataDir()) if the
303 application has several data files. In this case
304 wxCONFIG_USE_SUBDIR flag, which changes the default local
305 configuration file to "~/.appname/appname" should be used. Notice
306 that this flag is ignored if localFilename is provided.
307 wxCONFIG_USE_SUBDIR is new since wxWidgets version 2.8.2.
308 @n For wxFileConfig, you can also add
309 wxCONFIG_USE_NO_ESCAPE_CHARACTERS which will turn off character
310 escaping for the values of entries stored in the config file: for
311 example a foo key with some backslash characters will be stored as
312 "foo=C:\mydir" instead of the usual storage of "foo=C:\\mydir".
313 @n The wxCONFIG_USE_NO_ESCAPE_CHARACTERS style can be helpful if your
314 config file must be read or written to by a non-wxWidgets program
315 (which might not understand the escape characters). Note, however,
316 that if wxCONFIG_USE_NO_ESCAPE_CHARACTERS style is used, it is is
317 now your application's responsibility to ensure that there is no
318 newline or other illegal characters in a value, before writing that
321 This parameter is only used by wxFileConfig when compiled in
322 Unicode mode. It specifies the encoding in which the configuration
325 @remarks By default, environment variable expansion is on and recording
328 wxConfigBase(const wxString
& appName
= wxEmptyString
,
329 const wxString
& vendorName
= wxEmptyString
,
330 const wxString
& localFilename
= wxEmptyString
,
331 const wxString
& globalFilename
= wxEmptyString
,
333 const wxMBConv
& conv
= wxConvAuto());
336 Empty but ensures that dtor of all derived classes is virtual.
342 @name Path Management
344 See @ref configbase_paths
349 Retrieve the current path (always as absolute path).
351 const wxString
GetPath() const;
354 Set current path: if the first character is '/', it is the absolute
355 path, otherwise it is a relative path. '..' is supported. If @a strPath
356 doesn't exist it is created.
358 void SetPath(const wxString
& strPath
);
366 See @ref configbase_enumeration
371 Gets the first entry.
374 The wxPython version of this method returns a 3-tuple consisting of the
375 continue flag, the value string, and the index for the next call.
378 bool GetFirstEntry(wxString
& str
, long& index
) const;
381 Gets the first group.
384 The wxPython version of this method returns a 3-tuple consisting of the
385 continue flag, the value string, and the index for the next call.
388 bool GetFirstGroup(wxString
& str
, long& index
) const;
394 The wxPython version of this method returns a 3-tuple consisting of the
395 continue flag, the value string, and the index for the next call.
398 bool GetNextEntry(wxString
& str
, long& index
) const;
404 The wxPython version of this method returns a 3-tuple consisting of the
405 continue flag, the value string, and the index for the next call.
408 bool GetNextGroup(wxString
& str
, long& index
) const;
411 Get number of entries in the current group.
413 uint
GetNumberOfEntries(bool bRecursive
= false) const;
416 Get number of entries/subgroups in the current group, with or without
419 uint
GetNumberOfGroups(bool bRecursive
= false) const;
434 @name Tests of Existence
439 @return @true if either a group or an entry with a given name exists.
441 bool Exists(wxString
& strName
) const;
444 Returns the type of the given entry or @e Unknown if the entry doesn't
445 exist. This function should be used to decide which version of Read()
446 should be used because some of wxConfig implementations will complain
447 about type mismatch otherwise: e.g., an attempt to read a string value
448 from an integer key with wxRegConfig will fail.
450 wxConfigBase::EntryType
GetEntryType(const wxString
& name
) const;
453 @return @true if the entry by this name exists.
455 bool HasEntry(wxString
& strName
) const;
458 @return @true if the group by this name exists.
460 bool HasGroup(const wxString
& strName
) const;
466 @name Miscellaneous Functions
471 Returns the application name.
473 wxString
GetAppName() const;
476 Returns the vendor name.
478 wxString
GetVendorName() const;
486 See @ref configbase_keyaccess
491 Permanently writes all changes (otherwise, they're only written from
492 object's destructor).
494 bool Flush(bool bCurrentOnly
= false);
497 Read a string from the key, returning @true if the value was read. If
498 the key was not found, @a str is not changed.
500 bool Read(const wxString
& key
, wxString
* str
) const;
502 Read a string from the key. The default value is returned if the key
505 @return @true if value was really read, @false if the default was used.
507 const bool Read(const wxString
& key
, wxString
* str
,
508 const wxString
& defaultVal
) const;
510 Another version of Read(), returning the string value directly.
512 const wxString
Read(const wxString
& key
,
513 const wxString
& defaultVal
) const;
515 Reads a long value, returning @true if the value was found. If the
516 value was not found, @a l is not changed.
518 const bool Read(const wxString
& key
, long* l
) const;
520 Reads a long value, returning @true if the value was found. If the
521 value was not found, @a defaultVal is used instead.
523 const bool Read(const wxString
& key
, long* l
,
524 long defaultVal
) const;
526 Reads a double value, returning @true if the value was found. If the
527 value was not found, @a d is not changed.
529 const bool Read(const wxString
& key
, double* d
) const;
531 Reads a double value, returning @true if the value was found. If the
532 value was not found, @a defaultVal is used instead.
534 const bool Read(const wxString
& key
, double* d
,
535 double defaultVal
) const;
537 Reads a bool value, returning @true if the value was found. If the
538 value was not found, @a b is not changed.
540 const bool Read(const wxString
& key
, bool* b
) const;
542 Reads a bool value, returning @true if the value was found. If the
543 value was not found, @a defaultVal is used instead.
545 const bool Read(const wxString
& key
, bool* d
,
546 bool defaultVal
) const;
548 Reads a binary block, returning @true if the value was found. If the
549 value was not found, @a buf is not changed.
551 const bool Read(const wxString
& key
, wxMemoryBuffer
* buf
) const;
553 Reads a value of type T, for which function wxFromString() is defined,
554 returning @true if the value was found. If the value was not found,
555 @a value is not changed.
557 const bool Read(const wxString
& key
, T
* value
) const;
559 Reads a value of type T, for which function wxFromString() is defined,
560 returning @true if the value was found. If the value was not found,
561 @a defaultVal is used instead.
563 const bool Read(const wxString
& key
, T
* value
,
564 const T
& defaultVal
) const;
567 Reads a bool value from the key and returns it. @a defaultVal is
568 returned if the key is not found.
570 long ReadBool(const wxString
& key
, bool defaultVal
) const;
573 Reads a double value from the key and returns it. @a defaultVal is
574 returned if the key is not found.
576 long ReadDouble(const wxString
& key
, double defaultVal
) const;
579 Reads a long value from the key and returns it. @a defaultVal is
580 returned if the key is not found.
582 long ReadLong(const wxString
& key
, long defaultVal
) const;
585 Reads a value of type T (for which the function wxFromString() must be
586 defined) from the key and returns it. @a defaultVal is returned if the
589 T
ReadObject(const wxString
& key
, T
const& defaultVal
) const;
592 Writes the wxString value to the config file and returns @true on
595 bool Write(const wxString
& key
, const wxString
& value
);
597 Writes the long value to the config file and returns @true on success.
599 bool Write(const wxString
& key
, long value
);
601 Writes the double value to the config file and returns @true on
604 bool Write(const wxString
& key
, double value
);
606 Writes the bool value to the config file and returns @true on success.
608 bool Write(const wxString
& key
, bool value
);
610 Writes the wxMemoryBuffer value to the config file and returns @true on
613 bool Write(const wxString
& key
, const wxMemoryBuffer
& buf
);
615 Writes the specified value to the config file and returns @true on
616 success. The function wxToString() must be defined for type @e T.
618 bool Write(const wxString
& key
, T
const& buf
);
624 @name Rename Entries/Groups
626 These functions allow renaming entries or subgroups of the current
627 group. They will return @false on error, typically because either the
628 entry/group with the original name doesn't exist, because the
629 entry/group with the new name already exists or because the function is
630 not supported in this wxConfig implementation.
635 Renames an entry in the current group. The entries names (both the old
636 and the new one) shouldn't contain backslashes, i.e. only simple names
637 and not arbitrary paths are accepted by this function.
639 @return @false if @a oldName doesn't exist or if @a newName already
642 bool RenameEntry(const wxString
& oldName
, const wxString
& newName
);
645 Renames a subgroup of the current group. The subgroup names (both the
646 old and the new one) shouldn't contain backslashes, i.e. only simple
647 names and not arbitrary paths are accepted by this function.
649 @return @false if @a oldName doesn't exist or if @a newName already
652 bool RenameGroup(const wxString
& oldName
, const wxString
& newName
);
658 @name Delete Entries/Groups
660 These functions delete entries and/or groups of entries from the config
661 file. DeleteAll() is especially useful if you want to erase all traces
662 of your program presence: for example, when you uninstall it.
667 Delete the whole underlying object (disk file, registry key, ...).
668 Primarly for use by uninstallation routine.
673 Deletes the specified entry and the group it belongs to if it was the
674 last key in it and the second parameter is @true.
676 bool DeleteEntry(const wxString
& key
,
677 bool bDeleteGroupIfEmpty
= true);
680 Delete the group (with all subgroups). If the current path is under the
681 group being deleted it is changed to its deepest still existing
682 component. E.g. if the current path is @c "/A/B/C/D" and the group @c C
683 is deleted, the path becomes @c "/A/B".
685 bool DeleteGroup(const wxString
& key
);
693 Some aspects of wxConfigBase behaviour can be changed during run-time.
694 The first of them is the expansion of environment variables in the
695 string values read from the config file: for example, if you have the
696 following in your config file:
699 # config file for my program
700 UserData = $HOME/data
702 # the following syntax is valud only under Windows
703 UserData = %windir%\\data.dat
706 The call to Read("UserData") will return something like
707 @c "/home/zeitlin/data" on linux for example.
709 Although this feature is very useful, it may be annoying if you read a
710 value which containts '$' or '%' symbols (% is used for environment
711 variables expansion under Windows) which are not used for environment
712 variable expansion. In this situation you may call
713 SetExpandEnvVars(@false) just before reading this value and
714 SetExpandEnvVars(@true) just after. Another solution would be to prefix
715 the offending symbols with a backslash.
720 Returns @true if we are expanding environment variables in key values.
722 bool IsExpandingEnvVars() const;
725 Returns @true if we are writing defaults back to the config file.
727 bool IsRecordingDefaults() const;
730 Determine whether we wish to expand environment variables in key
733 void SetExpandEnvVars(bool bDoIt
= true);
736 Sets whether defaults are recorded to the config file whenever an
737 attempt to read the value which is not present in it is done.
739 If on (default is off) all default values for the settings used by the
740 program are written back to the config file. This allows the user to
741 see what config options may be changed and is probably useful only for
744 void SetRecordDefaults(bool bDoIt
= true);
750 Create a new config object: this function will create the "best"
751 implementation of wxConfig available for the current platform, see
752 comments near the definition of wxCONFIG_WIN32_NATIVE for details. It
753 returns the created object and also sets it as the current one.
755 static wxConfigBase
* Create();
758 Calling this function will prevent @e Get() from automatically creating
759 a new config object if the current one is @NULL. It might be useful to
760 call it near the program end to prevent "accidental" creation of a new
763 static void DontCreateOnDemand();
766 Get the current config object. If there is no current object and
767 @a CreateOnDemand is @true, this creates one (using Create()) unless
768 DontCreateOnDemand() was called previously.
770 static wxConfigBase
* Get(bool CreateOnDemand
= true);
773 Sets the config object as the current one, returns the pointer to the
774 previous current object (both the parameter and returned value may be
777 static wxConfigBase
* Set(wxConfigBase
* pConfig
);