wxConfigBase class defines the basic interface of all config classes. It can
not be used by itself (it is an abstract base class) and you will always use one
-of its derivations: wxIniConfig, wxFileConfig, wxRegConfig or any other.
+of its derivations: \helpref{wxFileConfig}{wxfileconfig},
+wxRegConfig or any other.
However, usually you don't even need to know the precise nature of the class
you're working with but you would just use the wxConfigBase methods. This
allows you to write the same code regardless of whether you're working with
the registry under Win32 or text-based config files under Unix (or even
Windows 3.1 .INI files if you're really unlucky). To make writing the portable
-code even easier, wxWindows provides a typedef wxConfig
+code even easier, wxWidgets provides a typedef wxConfig
which is mapped onto the native wxConfigBase implementation on the given
-platform: i.e. wxRegConfig under Win32, wxIniConfig under Win16 and
+platform: i.e. wxRegConfig under Win32 and
wxFileConfig otherwise.
See \helpref{config overview}{wxconfigoverview} for the descriptions of all
\wxheading{Include files}
-<wx/config.h> (to let wxWindows choose a wxConfig class for your platform)\\
+<wx/config.h> (to let wxWidgets choose a wxConfig class for your platform)\\
<wx/confbase.h> (base config class)\\
-<wx/fileconf.h> (wxFileconfig class)\\
-<wx/msw/regconf.h> (wxRegConfig class)\\
-<wx/msw/iniconf.h> (wxIniConfig class)
+<wx/fileconf.h> (wxFileConfig class)\\
+<wx/msw/regconf.h> (wxRegConfig class)
\wxheading{Example}
// another example: using default values and the full path instead of just
// key name: if the key is not found , the value 17 is returned
- long value = config->Read("/LastRun/CalculatedValues/MaxValue", -1);
+ long value = config->Read("/LastRun/CalculatedValues/MaxValue", 17);
...
...
...
\latexignore{\rtfignore{\wxheading{Function groups}}}
+
\membersection{Static functions}\label{wxconfigstaticfunctions}
These functions deal with the "default" config object. Although its usage is
one (especially because creating a wxFileConfig object might be a time
consuming operation). In this case, you may create this global config object
in the very start of the program and {\it Set()} it as the default. Then, from
-anywhere in your program, you may access it using the {\it Get()} function. Of
-course, you should delete it on the program termination (otherwise, not only a
-memory leak will result, but even more importantly the changes won't be
-written back!).
+anywhere in your program, you may access it using the {\it Get()} function.
+Note that you must delete this object (usually in \helpref{wxApp::OnExit}{wxapponexit})
+in order to avoid memory leaks, wxWidgets won't do it automatically.
As it happens, you may even further simplify the procedure described above:
you may forget about calling {\it Set()}. When {\it Get()} is called and there
is no current object, it will create one using {\it Create()} function. To
disable this behaviour {\it DontCreateOnDemand()} is provided.
-{\bf Note:} You should use either {\it Set()} or {\it Get()} because wxWindows
+{\bf Note:} You should use either {\it Set()} or {\it Get()} because wxWidgets
library itself would take advantage of it and could save various information
in it. For example \helpref{wxFontMapper}{wxfontmapper} or Unix version
of \helpref{wxFileDialog}{wxfiledialog} have ability to use wxConfig class.
\helpref{Create}{wxconfigbasecreate}\\
\helpref{DontCreateOnDemand}{wxconfigbasedontcreateondemand}
-\membersection{Constructor and destructor}
+
+\membersection{Constructor and destructor}\label{congigconstructordestructor}
\helpref{wxConfigBase}{wxconfigbasector}\\
\helpref{\destruct{wxConfigBase}}{wxconfigbasedtor}
-\membersection{Path management}
+
+\membersection{Path management}\label{configpathmanagement}
As explained in \helpref{config overview}{wxconfigoverview}, the config classes
support a file system-like hierarchy of keys (files) and groups (directories).
\helpref{SetPath}{wxconfigbasesetpath}\\
\helpref{GetPath}{wxconfigbasegetpath}
-\membersection{Enumeration}
+
+\membersection{Enumeration}\label{configenumeration}
The functions in this section allow to enumerate all entries and groups in the
-config file. All functions here return FALSE when there are no more items.
+config file. All functions here return false when there are no more items.
You must pass the same index to GetNext and GetFirst (don't modify it).
Please note that it is {\bf not} the index of the current item (you will have
-some great surprizes with wxRegConfig if you assume this) and you shouldn't
+some great surprises with wxRegConfig if you assume this) and you shouldn't
even look at it: it is just a "cookie" which stores the state of the
enumeration. It can't be stored inside the class because it would prevent you
from running several enumerations simultaneously, that's why you must pass it
\helpref{GetNumberOfEntries}{wxconfigbasegetnumberofentries}\\
\helpref{GetNumberOfGroups}{wxconfigbasegetnumberofgroups}
-\membersection{Tests of existence}
+
+\membersection{Tests of existence}\label{configtestsofexistence}
\helpref{HasGroup}{wxconfigbasehasgroup}\\
\helpref{HasEntry}{wxconfigbasehasentry}\\
\helpref{Exists}{wxconfigbaseexists}\\
\helpref{GetEntryType}{wxconfigbasegetentrytype}
-\membersection{Miscellaneous functions}
+
+\membersection{Miscellaneous functions}\label{configmiscellaneous}
\helpref{GetAppName}{wxconfigbasegetappname}\\
\helpref{GetVendorName}{wxconfigbasegetvendorname}\\
\helpref{SetUmask}{wxfileconfigsetumask}
-\membersection{Key access}
+
+\membersection{Key access}\label{configkeyaccess}
These function are the core of wxConfigBase class: they allow you to read and
write config file data. All {\it Read} function take a default value which
change in the near future). To work with other types: for {\it int} or {\it
bool} you can work with function taking/returning {\it long} and just use the
casts. Better yet, just use {\it long} for all variables which you're going to
-save in the config file: chances are that \verb$sizeof(bool) == sizeof(int) == sizeof(long)$ anyhow on your system. For {\it float}, {\it double} and, in
+save in the config file: chances are that {\tt sizeof(bool) == sizeof(int) == sizeof(long)} anyhow on your system. For {\it float}, {\it double} and, in
general, any other type you'd have to translate them to/from string
representation and use string functions.
\helpref{Write}{wxconfigbasewrite}\\
\helpref{Flush}{wxconfigbaseflush}
-\membersection{Rename entries/groups}
+
+\membersection{Rename entries/groups}\label{configrenaming}
The functions in this section allow to rename entries or subgroups of the
-current group. They will return FALSE on error. typically because either the
+current group. They will return false on error. typically because either the
entry/group with the original name doesn't exist, because the entry/group with
the new name already exists or because the function is not supported in this
wxConfig implementation.
\helpref{RenameEntry}{wxconfigbaserenameentry}\\
\helpref{RenameGroup}{wxconfigbaserenamegroup}
-\membersection{Delete entries/groups}
+
+\membersection{Delete entries/groups}\label{configdeleting}
The functions in this section delete entries and/or groups of entries from the
config file. {\it DeleteAll()} is especially useful if you want to erase all
\helpref{DeleteGroup}{wxconfigbasedeletegroup}\\
\helpref{DeleteAll}{wxconfigbasedeleteall}
-\membersection{Options}
+
+\membersection{Options}\label{configoptions}
Some aspects of wxConfigBase behaviour can be changed during run-time. The
first of them is the expansion of environment variables in the string values
# the following syntax is valud only under Windows
UserData = %windir%\\data.dat
\end{verbatim}
-
-the call to \verb$config->Read("UserData")$ will return something like
-\verb$"/home/zeitlin/data"$ if you're lucky enough to run a Linux system ;-)
+% $ % help EMACS syntax highlighting...
+the call to {\tt config->Read("UserData")} will return something like
+{\tt "/home/zeitlin/data"} if you're lucky enough to run a Linux system ;-)
Although this feature is very useful, it may be annoying if you read a value
which containts '\$' or '\%' symbols (\% is used for environment variables
expansion under Windows) which are not used for environment variable
-expansion. In this situation you may call SetExpandEnvVars(FALSE) just before
-reading this value and SetExpandEnvVars(TRUE) just after. Another solution
+expansion. In this situation you may call SetExpandEnvVars(false) just before
+reading this value and SetExpandEnvVars(true) just after. Another solution
would be to prefix the offending symbols with a backslash.
The following functions control this option:
}}
+
\membersection{wxConfigBase::wxConfigBase}\label{wxconfigbasector}
\func{}{wxConfigBase}{\param{const wxString\& }{appName = wxEmptyString},
\param{const wxString\& }{vendorName = wxEmptyString},
\param{const wxString\& }{localFilename = wxEmptyString},
\param{const wxString\& }{globalFilename = wxEmptyString},
- \param{long}{ style = 0}}
+ \param{long}{ style = 0},
+ \param{wxMBConv\&}{ conv = wxConvUTF8}}
This is the default and only constructor of the wxConfigBase class, and
derived classes.
the parameter is empty, the parameter will be set to a default. If the
parameter is present but the style flag not, the relevant flag will be added
to the style. For wxFileConfig you can also add wxCONFIG\_USE\_RELATIVE\_PATH
-by logicaly or'ing it to either of the \_FILE options to tell wxFileConfig to
-use relative instead of absolute paths. }
+by logically or'ing it to either of the \_FILE options to tell wxFileConfig to
+use relative instead of absolute paths. For wxFileConfig, you can also
+add wxCONFIG\_USE\_NO\_ESCAPE\_CHARACTERS which will turn off character
+escaping for the values of entries stored in the config file: for example
+a {\it foo} key with some backslash characters will be stored as {\tt foo=C:$\backslash$mydir} instead
+of the usual storage of {\tt foo=C:$\backslash\backslash$mydir}.
+
+The wxCONFIG\_USE\_NO\_ESCAPE\_CHARACTERS style can be helpful if your config
+file must be read or written to by a non-wxWidgets program (which might not
+understand the escape characters). Note, however, that if
+wxCONFIG\_USE\_NO\_ESCAPE\_CHARACTERS style is used, it is is now
+your application's responsibility to ensure that there is no newline or
+other illegal characters in a value, before writing that value to the file.}
+
+\docparam{conv}{This parameter is only used by wxFileConfig when compiled
+in Unicode mode. It specifies the encoding in which the configuration file
+is written.}
+
\wxheading{Remarks}
By default, environment variable expansion is on and recording defaults is
off.
+
\membersection{wxConfigBase::\destruct{wxConfigBase}}\label{wxconfigbasedtor}
\func{}{\destruct{wxConfigBase}}{\void}
Empty but ensures that dtor of all derived classes is virtual.
+
\membersection{wxConfigBase::Create}\label{wxconfigbasecreate}
\func{static wxConfigBase *}{Create}{\void}
near the definition of wxCONFIG\_WIN32\_NATIVE for details. It returns the
created object and also sets it as the current one.
+
\membersection{wxConfigBase::DontCreateOnDemand}\label{wxconfigbasedontcreateondemand}
\func{void}{DontCreateOnDemand}{\void}
new config object if the current one is NULL. It might be useful to call it
near the program end to prevent new config object "accidental" creation.
+
\membersection{wxConfigBase::DeleteAll}\label{wxconfigbasedeleteall}
\func{bool}{DeleteAll}{\void}
Delete the whole underlying object (disk file, registry key, ...). Primarly
for use by desinstallation routine.
+
\membersection{wxConfigBase::DeleteEntry}\label{wxconfigbasedeleteentry}
-\func{bool}{DeleteEntry}{\param{const wxString\& }{ key}, \param{bool}{ bDeleteGroupIfEmpty = TRUE}}
+\func{bool}{DeleteEntry}{\param{const wxString\& }{ key}, \param{bool}{ bDeleteGroupIfEmpty = true}}
Deletes the specified entry and the group it belongs to if it was the last key
in it and the second parameter is true.
+
\membersection{wxConfigBase::DeleteGroup}\label{wxconfigbasedeletegroup}
\func{bool}{DeleteGroup}{\param{const wxString\& }{ key}}
Delete the group (with all subgroups)
+
\membersection{wxConfigBase::Exists}\label{wxconfigbaseexists}
\constfunc{bool}{Exists}{\param{wxString\& }{strName}}
-returns TRUE if either a group or an entry with a given name exists
+returns true if either a group or an entry with a given name exists
+
\membersection{wxConfigBase::Flush}\label{wxconfigbaseflush}
-\func{bool}{Flush}{\param{bool }{bCurrentOnly = FALSE}}
+\func{bool}{Flush}{\param{bool }{bCurrentOnly = false}}
permanently writes all changes (otherwise, they're only written from object's
destructor)
+
\membersection{wxConfigBase::Get}\label{wxconfigbaseget}
-\func{wxConfigBase *}{Get}{\param{bool }{CreateOnDemand = TRUE}}
+\func{static wxConfigBase *}{Get}{\param{bool }{CreateOnDemand = true}}
Get the current config object. If there is no current object and
-{\it CreateOnDemand} is TRUE, creates one
+{\it CreateOnDemand} is true, creates one
(using {\it Create}) unless DontCreateOnDemand was called previously.
+
\membersection{wxConfigBase::GetAppName}\label{wxconfigbasegetappname}
\constfunc{wxString}{GetAppName}{\void}
Returns the application name.
+
\membersection{wxConfigBase::GetEntryType}\label{wxconfigbasegetentrytype}
\constfunc{enum wxConfigBase::EntryType}{GetEntryType}{\param{const wxString\& }{name}}
};
\end{verbatim}
+
\membersection{wxConfigBase::GetFirstGroup}\label{wxconfigbasegetfirstgroup}
\constfunc{bool}{GetFirstGroup}{\param{wxString\& }{str}, \param{long\&}{ index}}
consisting of the continue flag, the value string, and the index for
the next call.}
+\perlnote{In wxPerl this method takes no arguments and returns a 3-element
+list {\tt ( continue, str, index )}.}
+
+
\membersection{wxConfigBase::GetFirstEntry}\label{wxconfigbasegetfirstentry}
\constfunc{bool}{GetFirstEntry}{\param{wxString\& }{str}, \param{long\&}{ index}}
consisting of the continue flag, the value string, and the index for
the next call.}
+\perlnote{In wxPerl this method takes no arguments and returns a 3-element
+list {\tt ( continue, str, index )}.}
+
+
\membersection{wxConfigBase::GetNextGroup}\label{wxconfigbasegetnextgroup}
\constfunc{bool}{GetNextGroup}{\param{wxString\& }{str}, \param{long\&}{ index}}
consisting of the continue flag, the value string, and the index for
the next call.}
+\perlnote{In wxPerl this method only takes the {\tt index} parameter
+and returns a 3-element list {\tt ( continue, str, index )}.}
+
+
\membersection{wxConfigBase::GetNextEntry}\label{wxconfigbasegetnextentry}
\constfunc{bool}{GetNextEntry}{\param{wxString\& }{str}, \param{long\&}{ index}}
consisting of the continue flag, the value string, and the index for
the next call.}
+\perlnote{In wxPerl this method only takes the {\tt index} parameter
+and returns a 3-element list {\tt ( continue, str, index )}.}
+
+
\membersection{wxConfigBase::GetNumberOfEntries}\label{wxconfigbasegetnumberofentries}
-\constfunc{uint }{GetNumberOfEntries}{\param{bool }{bRecursive = FALSE}}
+\constfunc{uint }{GetNumberOfEntries}{\param{bool }{bRecursive = false}}
+
\membersection{wxConfigBase::GetNumberOfGroups}\label{wxconfigbasegetnumberofgroups}
-\constfunc{uint}{GetNumberOfGroups}{\param{bool }{bRecursive = FALSE}}
+\constfunc{uint}{GetNumberOfGroups}{\param{bool }{bRecursive = false}}
Get number of entries/subgroups in the current group, with or without its
subgroups.
+
\membersection{wxConfigBase::GetPath}\label{wxconfigbasegetpath}
\constfunc{const wxString\&}{GetPath}{\void}
Retrieve the current path (always as absolute path).
+
\membersection{wxConfigBase::GetVendorName}\label{wxconfigbasegetvendorname}
\constfunc{wxString}{GetVendorName}{\void}
Returns the vendor name.
+
\membersection{wxConfigBase::HasEntry}\label{wxconfigbasehasentry}
\constfunc{bool}{HasEntry}{\param{wxString\& }{strName}}
-returns TRUE if the entry by this name exists
+returns true if the entry by this name exists
+
\membersection{wxConfigBase::HasGroup}\label{wxconfigbasehasgroup}
\constfunc{bool}{HasGroup}{\param{const wxString\& }{strName}}
-returns TRUE if the group by this name exists
+returns true if the group by this name exists
+
\membersection{wxConfigBase::IsExpandingEnvVars}\label{wxconfigbaseisexpandingenvvars}
\constfunc{bool}{IsExpandingEnvVars}{\void}
-Returns TRUE if we are expanding environment variables in key values.
+Returns true if we are expanding environment variables in key values.
+
\membersection{wxConfigBase::IsRecordingDefaults}\label{wxconfigbaseisrecordingdefaults}
\constfunc{bool}{IsRecordingDefaults}{\void}
-Returns TRUE if we are writing defaults back to the config file.
+Returns true if we are writing defaults back to the config file.
+
\membersection{wxConfigBase::Read}\label{wxconfigbaseread}
\constfunc{bool}{Read}{\param{const wxString\& }{key}, \param{wxString*}{ str}}
-Read a string from the key, returning TRUE if the value was read. If the key
+Read a string from the key, returning true if the value was read. If the key
was not found, {\it str} is not changed.
\constfunc{bool}{Read}{\param{const wxString\& }{key}, \param{wxString*}{ str}, \param{const wxString\& }{defaultVal}}
Read a string from the key. The default value is returned if the key was not
found.
-Returns TRUE if value was really read, FALSE if the default was used.
+Returns true if value was really read, false if the default was used.
\constfunc{wxString}{Read}{\param{const wxString\& }{key}, \param{const
wxString\& }{defaultVal}}
\constfunc{bool}{Read}{\param{const wxString\& }{ key}, \param{long*}{ l}}
-Reads a long value, returning TRUE if the value was found. If the value was
+Reads a long value, returning true if the value was found. If the value was
not found, {\it l} is not changed.
\constfunc{bool}{Read}{\param{const wxString\& }{ key}, \param{long*}{ l},
\param{long}{ defaultVal}}
-Reads a long value, returning TRUE if the value was found. If the value was
+Reads a long value, returning true if the value was found. If the value was
not found, {\it defaultVal} is used instead.
\constfunc{long }{Read}{\param{const wxString\& }{key}, \param{long}{ defaultVal}}
NB: writing
-{\small \begin{verbatim} conf->Read("key", 0); \end{verbatim} }
+{\small
+\begin{verbatim}
+ conf->Read("key", 0);
+\end{verbatim}
+}
won't work because the call is ambiguous: compiler can not choose between two
{\it Read} functions. Instead, write:
-{\small \begin{verbatim} conf->Read("key", 0l); \end{verbatim} }
+{\small
+\begin{verbatim}
+ conf->Read("key", 0l);
+\end{verbatim}
+}
\constfunc{bool}{Read}{\param{const wxString\& }{ key}, \param{double*}{ d}}
-Reads a double value, returning TRUE if the value was found. If the value was
+Reads a double value, returning true if the value was found. If the value was
not found, {\it d} is not changed.
\constfunc{bool}{Read}{\param{const wxString\& }{ key}, \param{double*}{ d},
\param{double}{ defaultVal}}
-Reads a double value, returning TRUE if the value was found. If the value was
+Reads a double value, returning true if the value was found. If the value was
not found, {\it defaultVal} is used instead.
\constfunc{bool}{Read}{\param{const wxString\& }{ key}, \param{bool*}{ b}}
-Reads a bool value, returning TRUE if the value was found. If the value was
+Reads a bool value, returning true if the value was found. If the value was
not found, {\it b} is not changed.
\constfunc{bool}{Read}{\param{const wxString\& }{ key}, \param{bool*}{ d},
\param{bool}{ defaultVal}}
-Reads a bool value, returning TRUE if the value was found. If the value was
+Reads a bool value, returning true if the value was found. If the value was
not found, {\it defaultVal} is used instead.
\pythonnote{In place of a single overloaded method name, wxPython
\end{twocollist}}
}
+\perlnote{In place of a single overloaded method, wxPerl uses:\par
+\indented{2cm}{\begin{twocollist}
+\twocolitem{{\bf Read(key, default="")}}{Returns a string}
+\twocolitem{{\bf ReadInt(key, default=0)}}{Returns an integer}
+\twocolitem{{\bf ReadFloat(key, default=0.0)}}{Returns a floating point number}
+\twocolitem{{\bf ReadBool(key, default=0)}}{Returns a boolean}
+\end{twocollist}
+}}
+
+
\membersection{wxConfigBase::RenameEntry}\label{wxconfigbaserenameentry}
\func{bool}{RenameEntry}{\param{const wxString\& }{ oldName}, \param{const wxString\& }{ newName}}
the new one) shouldn't contain backslashes, i.e. only simple names and not
arbitrary paths are accepted by this function.
-Returns FALSE if the {\it oldName} doesn't exist or if {\it newName} already
+Returns false if the {\it oldName} doesn't exist or if {\it newName} already
exists.
+
\membersection{wxConfigBase::RenameGroup}\label{wxconfigbaserenamegroup}
\func{bool}{RenameGroup}{\param{const wxString\& }{ oldName}, \param{const wxString\& }{ newName}}
the new one) shouldn't contain backslashes, i.e. only simple names and not
arbitrary paths are accepted by this function.
-Returns FALSE if the {\it oldName} doesn't exist or if {\it newName} already
+Returns false if the {\it oldName} doesn't exist or if {\it newName} already
exists.
+
\membersection{wxConfigBase::Set}\label{wxconfigbaseset}
-\func{wxConfigBase *}{Set}{\param{wxConfigBase *}{pConfig}}
+\func{static wxConfigBase *}{Set}{\param{wxConfigBase *}{pConfig}}
Sets the config object as the current one, returns the pointer to the previous
current object (both the parameter and returned value may be NULL)
+
\membersection{wxConfigBase::SetExpandEnvVars}\label{wxconfigbasesetexpandenvvars}
-\func{void}{SetExpandEnvVars }{\param{bool }{bDoIt = TRUE}}
+\func{void}{SetExpandEnvVars }{\param{bool }{bDoIt = true}}
Determine whether we wish to expand environment variables in key values.
+
\membersection{wxConfigBase::SetPath}\label{wxconfigbasesetpath}
\func{void}{SetPath}{\param{const wxString\& }{strPath}}
otherwise it is a relative path. '..' is supported. If the strPath doesn't
exist it is created.
-\membersection{wxConfigBase::SetRecordDefaults}\label{wxconfigbasesetrecorddefaults}
-
-\func{void}{SetRecordDefaults}{\param{bool }{bDoIt = TRUE}}
-
-Sets whether defaults are written back to the config file.
-If on (default is off) all default values are written back to the config file.
-This allows the user to see what config options may be changed and is probably
-useful only for wxFileConfig.
+\membersection{wxConfigBase::SetRecordDefaults}\label{wxconfigbasesetrecorddefaults}
-\membersection{wxConfigBase::SetUmask}\label{wxfileconfigsetumask}
+\func{void}{SetRecordDefaults}{\param{bool }{bDoIt = true}}
-\func{void}{SetUmask}{\param{int }{mode}}
+Sets whether defaults are recorded to the config file whenever an attempt to
+read read the value which is not present in it is done.
-{\bf NB:} this function is not in the base wxConfigBase class but is only
-implemented in wxFileConfig. Moreover, this function is Unix-specific and
-doesn't do anything on other platforms.
+If on (default is off) all default values for the settings used by the program
+are written back to the config file. This allows the user to see what config
+options may be changed and is probably useful only for wxFileConfig.
-SetUmask() allows to set the mode to be used for the config file creation.
-For example, to create a config file which is not readable by other users
-(useful if it stores some sensitive information, such as passwords), you
-should do {\tt SetUmask(0077)}.
\membersection{wxConfigBase::Write}\label{wxconfigbasewrite}
\func{bool}{Write}{\param{const wxString\& }{ key}, \param{bool}{ value}}
-These functions write the specified value to the config file and return TRUE
+These functions write the specified value to the config file and return true
on success.
\pythonnote{In place of a single overloaded method name, wxPython
\end{twocollist}}
}
+\perlnote{In place of a single overloaded method, wxPerl uses:\par
+\indented{2cm}{\begin{twocollist}
+\twocolitem{{\bf Write(key, value)}}{Writes a string}
+\twocolitem{{\bf WriteInt(key, value)}}{Writes an integer}
+\twocolitem{{\bf WriteFloat(key, value)}}{Writes a floating point number}
+\twocolitem{{\bf WriteBool(key, value)}}{Writes a boolean}
+\end{twocollist}
+}}
+
projects / wxWidgets.git / blobdiff