calamares/HACKING.md

Hacking on Calamares

Join #calamares on Freenode.

Patches go to github.com/calamares.

Formatting

• Spaces, not tabs.
• Indentation is 4 spaces.
• Lines should be limited to 90 characters.
• Spaces between brackets and argument functions, including for template arguments
• No space before brackets, except for keywords, for example function( argument ) but if ( condition ).
• For pointer and reference variable declarations, put a space before the variable name and no space between the type and the * or &.
• for, if, else, while and similar statements put the brackets on the next line, although brackets are not needed for single statements.
• Function and class definitions have their brackets on separate lines.
• A function implementation's return type is on its own line.
• CamelCase.{cpp,h} style file names.

Example:

bool
MyClass::myMethod( QStringList list, const QString& name )
{
    if ( list.isEmpty() )
        return false;

    foreach ( const QString& string, list )
        cDebug() << "Current string is " << string;

    switch ( m_enumValue )
    {
    case Something:
        return true;
    case SomethingElse:
        doSomething();
        break;
    }
}

Naming

• Use CamelCase for everything.
• Local variables should start out with a lowercase letter.
• Class names are captialized
• Prefix class member variables with m_, e.g. m_queue.
• Prefix static member variables with s_, e.g. s_instance.
• Functions are named in the Qt style, like Java's, without the 'get' prefix.
  • A getter is variable().
  • If it's a getter for a boolean, prefix with 'is', so isCondition().
  • A setter is setVariable( arg ).

Includes

Header includes should be listed in the following order:

• own header,
• Calamares includes,
• includes for Qt-based libraries,
• Qt includes,
• other includes.

They should also be sorted alphabetically for ease of locating them.

Includes in a header file should be kept to the absolute minimum, as to keep compile times short. This can be achieved by using forward declarations instead of includes, like class QListView;.

Example:

#include "Settings.h"

#include "CalamaresApplication.h"
#include "utils/CalamaresUtils.h"
#include "utils/Logger.h"
#include "YamlUtils.h"

#include <QDir>
#include <QFile>

#include <yaml-cpp/yaml.h>

Use include guards, not #pragma once.

C++ tips

All C++11 features are acceptable, and the use of new C++11 features is encouraged when it makes the code easier to understand and more maintainable.

The use of nullptr is preferred over the use of 0 or NULL.

For Qt containers it is better to use Qt's own foreach. For all other containers, the range-based for syntax introduced with C++11 is preferred (see this blog post).

When reimplementing a virtual method, always add the override keyword.

Try to keep your code const correct. Declare methods const if they don't mutate the object, and use const variables. It improves safety, and also makes it easier to understand the code.

For the Qt signal-slot system, the new (Qt5) syntax is to be preferred because it allows the compiler to check for the existence of signals and slots. As an added benefit, the new syntax can also be used with tr1::bind and C++11 lambdas. For more information, see the Qt wiki.

Example:

connect( m_next, &QPushButton::clicked, this, &ViewManager::next );

connect( m_moduleManager, &Calamares::ModuleManager::modulesLoaded, [this]
{
    m_mainwindow->show();
});

Debugging

Use cDebug() and cLog() from utils/Logger.h.