QExt

Purpose

QExt is an add-on library for Qt developers with no other dependancies. The aims of QExt in a nutshell are:

• Ease C++14/C++17 use with Qt
• Limit "rolling-your-own"
• Extend Qt's capabilities in common scenarios

Features

QExt makes "Qt-style" pImpl development easier, such as support for Qt's d-ptr (also known as the compiler firewall), including Private class inheritance and back links (see qe::PublicBase and qe::PrivateBase in the core module).

Modern C++

C++14 is used throughout the library to speed, ease, and simplify development. One of the benefits of this are macros that replace Q_D and Q_Q without needing a class name declaration (QE_D and QE_Q). This is legal code in QExt:

void MyPublicClass::setFoo(const Foo &f)
{
   //Q_D(MyPublicClass); <--Not needed
   QE_D; //This works instead, along with QE_DPTR
   d->foo = f;
}

bool MyPublicClass::hasFoo() const 
{
    //Q_D(const MyPublicClass); <--nope
    QE_CONST_D; //QE_CD is an option for brevity
    return d->foo;
}

Another feature of QExt is a "moveable QScopedPointer", implemented as qe::UniquePointer. It's essentially QScopedPointer with move semantics and is compatible with QScopedPointerDeleter. However, it was designed with modern C++ in mind and written with both Standard Library-style and Qt-style accessors (e.g. get() and data() are synonymous).

Windows and COM

qe::windows::UnknownPointer<T> is a header-only wrapper around IUnknown pointers. It will add your ->AddRef()s and release your ->Release()'s. It will copy and move intelligently. It also returns itself as T** via ptr.addressOf() and even as void * and void ** with ptr.pVoid() and ptr.ppVoid().

The qe::windows::shell namespace and member classes make handling PIDLs and IShellItem/IShellFolder interfaces much easier. qe::windows::shell::IdList is an efficient, header only wrapper around an ITEMIDLIST pointer. It provides platform-safe casting between the many PIDL typedefs, a const_iterator, and noexcept member functions that replace common IL* ShlObj.h functions. IdList will even guess at the type of data it represents based on the abID[0] value of the final element.

Eventual plans for QExt include a library of useful widgets (QeWidgets) and more Windows/COM tools in QeWindows.

Status

QExt is currently beta in the QeCore module and unstable (pre-alpha) in the QeWindows module.

QeCore

The core module is relatively stable. API changes are unlikely. Classes and functions may be added in the future, but in their own headers.

QeWidgets

This module needs a lot of love. It has not been merged because of this.

QeWindows

• VARIANT and PROPVARIANT to QVariant conversion functions are done except for &%$@ing SAFEARRAY values and unconvertible (to Qt) types, like VT_CY.
• Numerous low-level functions done
• shell::IdList is working and nearly complete
• ShellNode: needs a unit test
• ShellNodeInfo: missing lots of functionality at present

License

QExt is released under the GNU General Public License Version 3.

Contributing

This is a hobby project, so development may be slow. That said, this is GitHub. Branch (and fork) away.

Coding Style

QExt is written in a form of the Qt development style, which is (circularly) dependant upon the KDE style. That is, classes are InitialCaps, functions are camelCased.

Note that QExt supports namespaces, and is written within them. Qt-style type aliases are available with logical names. For example: qecore/uniquepointer.h contains the definition of qe::UniquePointer with an including using declaration for QeUniquePointer. Use the preprocessor defintion QEXT_NO_CLUTTER to disable these typedefs.

In QExt, a namespace will always be lower cased in order to distinguish namespaces from classes.