View source for Kexi/Junior Jobs/Add d-pointers

'''Status: done'''<div style="float:right;padding:1em;">https://developers.google.com/open-source/gci/2012/logo.png</div>

*maintainer of this task: staniek at kde.org
*DIFFICULTY=2/5
*Offered within [http://www.google-melange.com/gci/homepage/google/gci2012 Google Code-IN] program; splitted to two tasks:
**[http://www.google-melange.com/gci/task/view/google/gci2012/7971213 Part 1]
**[https://google-melange.appspot.com/gci/task/view/google/gci2012/8009216 Part 2]

==Goal==
Improve internal APIs in Kexi. This can be done easily by introducing d-pointers to classes that lack them.

==Introduction==
Read section about d-pointers on [http://techbase.kde.org/Policies/Library_Code_Policy#D-Pointers|KDE Techbase] (d-pointers only, not shared d-pointers).

Classes that have to be converted are in this form:

<source lang="cpp-qt">
 // MyClass.h
 class MyClass {
 public:
  MyClass();
 private:
  Foo m_foo;
 };
 
 // MyClass.cpp
 MyClass::MyClass() {
  m_foo/doSomething();
 }
</source>

After converting to d-pointer it should be:

<source lang="cpp-qt">
 // MyClass.h
 class MyClass {
 public:
  MyClass();
 private:
  class Private;
  Private * const d;
 };
 
 // MyClass.cpp
 class MyClass::Private {
 public:
  Private() 
  Foo foo;
 };
 
 MyClass::MyClass()
  : d(new Private)
 {
  d->foo.doSomething();
 }
 
 MyClass::~MyClass()
 {
  delete d;
 }
</source>

==Further tasks==
Converting non-trivial classes to use d-pointer may also require:
*any code in the class' .cpp file referring to m_foo attribute should be changed to d->foo
*if there were public or protected member variables, move them to the d-pointer class and add accessors and setters for them as in the example below. Read about guildelines for accessors and setters on [http://techbase.kde.org/Policies/Library_Code_Policy#Naming_Conventions Techbase].
<source lang="cpp-qt">
 // MyClass.h
 class MyClass {
 public:
  MyClass();
  bool isBlack;
 };
</source>

After converting to d-pointer it should be:

<source lang="cpp-qt">
 // MyClass.h
 class MyClass {
 public:
  MyClass();
  bool isBlack() const; // notice the const
  void setBlack(bool black);
 private:
  class Private;
  Private * const d;
 };
 
 // MyClass.cpp
 class MyClass::Private {
 public:
  Private() 
  bool isBlack;
 };
 
 MyClass::MyClass()
  : d(new Private)
 {
  d->foo.doSomething();
 }
 
 MyClass::~MyClass()
 {
  delete d;
 }
 
 bool isBlack() const
 {
  return d->isBlack;
 }
 void setBlack(bool black)
 {
  d->isBlack = black;
 }
</source>

*The class typically should be "non-copyable" and thus add Q_DISABLE_COPY(...) line in private section of the class as presented below to avoid copying what would conflict with the d-pointer. This macro disables copy constructor and assignment operator. See the [http://doc.qt.io/qt-5/qobject.html#Q_DISABLE_COPY Qt docs] for more information.
<source lang="cpp-qt">
 class MyClass
 {                                                                   
  // ...
 private:
  Q_DISABLE_COPY(MyClass)
  // ...
 };
</source>
*Alter any code outside of the class that uses the class' API so that the code compiles and runs in exactly the same way as before.
*If there is inline code in header file that uses member variable, move the variable to d-pointer class if you know for sure the inline code isn't there for optimization. If unsure, ask the mentor or the task maintainer.
*After the work is done, the code should be compiled and possibly the program should be executed to check if there are no regressions.

==List of files==
This list can be extended if student finished the work. If you're looking for more please contact the mentor. Please prepend items with with [done] tag here when done. Please do not change any other APIs without prior contacting the mentor. '''Please read Notes below''' and make sure you understand them (as if unsure).

===Part 1===
For [http://www.google-melange.com/gci/task/view/google/gci2012/7971213 Part 1] of the task.


*In kexi/widget/
**[done]kexicharencodingcombobox.*
**[done]kexidbconnectionwidget.*
**[done]kexidbdrivercombobox.*
**[done]KexiConnectionSelectorWidget.* (not submitted)
**[done]KexiProjectSelectorWidget.*
**[done]kexiscrollview.*
**[done]KexiNameDialog.* (not submitted)
**[done]KexiNameWidget.* (not submitted)
**[done]KexiTableViewColumn.* (not submitted)
**[done]kexidataawarepropertyset.* (not submitted)
**[done]kexidataawareview.* (not submitted)
**[done]KexiFieldListModelItem.* (not submitted)
**[done]KexiFieldListView.* (not submitted)
**[done]kexislider.* (not submitted)
**[done]KexiProjectModelItem.* (not submitted)
**[done]KexiProjectNavigator.* (not submitted)
**[done]KexiDockableWidget.* (not submitted)
**[done]kexicomboboxdropdownbutton.* (not submitted)
**[done]kexidatetimeformatter.* (not submitted)
**[done]kexitooltip.* (not submitted)

*In kexi/plugins/forms/
**[done]kexiformscrollview.*
**[done]kexiformview.* (not submitted)
**[done]kexidbutils.* (not submitted)

*In kexi/plugins/reports/
**[done]kexireportdata.* (not submitted)
**[done]kexisourceselector.* (not submitted)
**[done]keximigratereportdata.* (not submitted)

*In kexi/plugins/importexport/csv/
**[done]kexicsvwidgets.* (not submitted)

*In kexi/migration/
**[done]importwizard.* (not submitted)
**[done]keximigrate.* (not submitted)

===Part 2===
For [https://google-melange.appspot.com/gci/task/view/google/gci2012/8009216 Part 2] of the task.

*In kexi/core/
**[done]kexidataiteminterface.*
**[done]kexiinternalpart.*
**[done]kexipartmanager.*
**[done]kexiprojectconnectiondata.*
**[done]kexistartupdata.*
**[done]kexitextmsghandler.*
**[done]KexiView.* (just m_defaultIconName)

*In kexi/main/
**[done]KexiStartup.*
**[done]KexiTemplatesModel.*

*In kexi/kexiutils/
**[done]FlowLayout.* (and move all inline code to .cpp)
**[done]longlongvalidator.*
**[done]SmallToolButton.* (KexiToolBarSeparator)

*In kexi/formeditor/
**[done]connectiondialog.*
**[done]container.*
**[done]events.*
**[done]FormWidget.*
**[done]kexiformeventhandler.*
**[done]libactionwidget.*
**[done]objecttree.*
**[done]resizehandle.*
**[done]richtextdialog.*
**[done]tabstopdialog.*
**[done]widgetfactory.*
**[done]WidgetTreeWidget.*
**[done]widgetwithsubpropertiesinterface.*

==Required skills==
Average C++ needed, at least beginner, Qt knowledge welcome.

==Notes==
*To start, build Kexi ([[Calligra/Building]]) from master git branch
*If you want to write proper code, please get accustomed with KDE Policies [http://techbase.kde.org/Policies Policies], especially coding style (inherited from KDElibs) policies; see also [http://techbase.kde.org/Development/Tutorials/Common_Programming_Mistakes Common programming mistakes]
*A lot of changes will be needed to make Kexi build properly again after removing m_* attributes (getters/setters will be used instead of attributes)
*Please take care about constness of returned value (if needed), make getters const, and setters non-const
*Do not return by reference -- use the advantage of [http://doc.qt.digia.com/qt/implicit-sharing.html implicit sharing]
*If the attribute was private, do not add getter/setter for it
*If the attribute was protected, add protected getter/setter for it
*If the attribute was public, add public getter/setter for it
*Do not add d-pointer to internal structures, often indicated by *_p.h name of the header (this makes no sense)
*This task can be naturally splited to many students but please have consistency in mind
*Results are stored within a new branch kexi-dpointers-gci, should be created and maintained by mentor
*The resulting patche(s) should be also uploaded to http://git.reviewboard.kde.org:
**split patches per-directory (e.g. kexi/widget/) to make the patches smaller (so it's easier to review)
**For more comfortable work: on reviewboard, when given issue gets fixed, please click Fixed button; see [http://www.reviewboard.org/docs/manual/1.7/users/reviews/issue-tracking/#responding-to-issues]
*The final commits to git will go to the '''master''' branch and should be splitted per class
*The mentor should synchronize students' work within the single branch
*Please always emphasize importance of coding style to students and check that - it's so easier to maintain the style from day one instead of fixing afterwards. Show [http://techbase.kde.org/Policies/Kdelibs_Coding_Style Techbase articles] for that.
*Take care of coding practices too (see [http://techbase.kde.org/Development/Tutorials/Common_Programming_Mistakes Techbase articles])