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ctkPimpl Class Reference

Utility macros for handling private implementations. It is in addition to QtGlobal: Q_DECLARE_PRIVATE, Q_DECLARE_PUBLIC, Q_D and Q_Q. More...

#include <Code/ExternalCode/ctk/ctkPimpl.h>

Related Functions

(Note that these are not member functions.)

#define CTK_CONSTRUCTOR_1_ARG_CPP(PUB, _ARG1)
 
#define CTK_CONSTRUCTOR_NO_ARG_CPP(PUB)
 
#define CTK_GET_CPP(PUB, _TYPE, _NAME, _VARNAME)
 
#define CTK_SET_CPP(PUB, _TYPE, _NAME, _VARNAME)
 

Detailed Description

Utility macros for handling private implementations. It is in addition to QtGlobal: Q_DECLARE_PRIVATE, Q_DECLARE_PUBLIC, Q_D and Q_Q.

Application code generally doesn't have to be concerned about hiding its implementation details, but when writing library code it is important to maintain a constant interface, both source and binary. Maintaining a constant source interface is easy enough, but keeping the binary interface constant means moving implementation details into a private class. The PIMPL, or d-pointer, idiom is a common method of implementing this separation. ctkPimpl offers a convenient way to connect the public and private sides of your class.

Getting Started

Before you declare the public class, you need to make a forward declaration of the private class. The private class must have the same name as the public class, followed by the word Private.

The Public Class

Generally, you shouldn't keep any data members in the public class without a good reason. Functions that are part of the public interface should be declared in the public class, and functions that need to be available to subclasses (for calling or overriding) should be in the protected section of the public class. To connect the private class to the public class, include the Q_DECLARE_PRIVATE macro in the private section of the public class.

Additionally, you must construct the d_ptr pointer in the constructor of the public class.

The Private Class

As mentioned above, data members should usually be kept in the private class. This allows the memory layout of the private class to change without breaking binary compatibility for the public class. Functions that exist only as implementation details, or functions that need access to private data members, should be implemented here.

To define the private class, nothing special needs to be done, except if you want the private class to have access to the public class. Then use Q_DECLARE_PUBLIC and create a public class pointer member. The constructor of the private class should take a public class reference as a parameter.

Accessing Private Members

Use the Q_D() macros from functions in the public class to access the private class. Similarly, functions in the private class can invoke functions in the public class by using the Q_Q() macro.

Friends And Related Function Documentation

#define CTK_CONSTRUCTOR_1_ARG_CPP (   PUB,
  _ARG1 
)
related
Value:
PUB::PUB(_ARG1 _parent) \
: Superclass( _parent ) \
, d_ptr(new PUB##Private) \
{ \
}

Define a public class constructor with one argument

Also make sure the Pimpl is initalized

Definition at line 71 of file ctkPimpl.h.

#define CTK_CONSTRUCTOR_NO_ARG_CPP (   PUB)
related
Value:
PUB::PUB(): d_ptr(new PUB##Private) \
{ \
}

Define a public class constructor with no argument

Also make sure the Pimpl is initalized

Definition at line 61 of file ctkPimpl.h.

#define CTK_GET_CPP (   PUB,
  _TYPE,
  _NAME,
  _VARNAME 
)
related
Value:
_TYPE PUB::_NAME()const \
{ \
Q_D(const PUB); \
return d->_VARNAME; \
}

Define the setter in the public class.

This should be put in the .cxx file of the public class. The parameter are the name of the public class (PUB), the type of the argument to return (_TYPE), the name of the setter(_NAME) and the name of the variable in the Private class(_VARNAME).

Definition at line 99 of file ctkPimpl.h.

#define CTK_SET_CPP (   PUB,
  _TYPE,
  _NAME,
  _VARNAME 
)
related
Value:
void PUB::_NAME(_TYPE var) \
{ \
Q_D(PUB); \
d->_VARNAME = var; \
}

Define the setter in the public class.

This should be put in the .cxx file of the public class. The parameter are the name of the public class (PUB), the type of the argument to return (_TYPE), the name of the getter(_NAME) and the name of the variable in the Private class(_VARNAME).

Definition at line 85 of file ctkPimpl.h.


The documentation for this class was generated from the following file: