awesome-widgets/CONTRIBUTING.md

229 lines
9.7 KiB
Markdown

Code style
----------
The recommended code style is Qt one. See [this document](https://wiki.qt.io/Qt_Coding_Style)
for more details. To avoid manual labor there is automatic cmake target named
`clangformat` (see below). Some additional detail see below.
* Indent is only spaces. 4 spaces.
* Any private variable should start with `m_` prefix (`m_foo`). The only one
exception is `Ui` object which should be named as `ui`.
* Avoid to create a large methods. Exception: if method contains lambda functions.
* If some method is called only once, it is recommended to use lambda functions.
Exception is `Q_INVOKABLE` methods.
* STL containers are not recommended, use Qt ones instead.
* In other hand Qt specific variables types (`qint`, `qfloat`, etc) are not
recommended.
* Do not repeat yourself ([DRY](https://en.wikipedia.org/wiki/Don't_repeat_yourself)).
* Headers declaration:
* Include only those headers which are strictly necessary inside headers. Use
forward class declaration instead. Exception is base class header declaration.
* In a`*.cpp` file header declaration should have the following order separated
by a new line in the alphabet order:
1. Class header.
2. KDE specific headers.
3. Qt specific headers.
4. Third party headers.
5. Project headers.
* Any header should have [include guard](https://en.wikipedia.org/wiki/Include_guard)
named as `CLASSNAMECAPS_H`
* If any `#if` directive is used condition should be mentioned in `#endif`:
```
#if (FOO)
someCodeInside();
#endif /* FOO */
```
* `Q_PROPERTY` macro is allowed and recommended for QObject based classes.
* Qt macros (e.g. `signals`, `slots`, `Q_OBJECT`, etc) are allowed. In other hand
`Q_FOREACH` (`foreach`) is not allowed use `for (auto &foo : bar)` instead.
* Current project standard is **C++17**.
* Do not use C-like code:
* C-like style iteration if possible. Use `for (auto &foo : bar)` and
`std::for_each` instead if possible. It is also recommended to use iterators.
* C-like casts, use `const_cast`, `static_cast`, `dymanic_Cast` instead. Using
of `reinterpret_cast` is not recommended. It is highly recommended to use
`dynamic_cast` with the exception catching. It is also possible to use
`qvariant_cast` if required.
* C-like `NULL`, use `nullptr` instead.
* C-like constant definition, use `const vartype foo = bar` definition instead.
* Abstract classes (which have at least one pure virtual method) are allowed.
* Templates are allowed and recommended. Templates usually should be described
inside header not source code file.
* Hardcode is not recommended. But it is possible to use cmake variables to
configure some items during build time.
* Build should not require any additional system variable declaration/changing.
* Any line should not end with space.
* Do not hesitate move public methods to private one if possible.
* Do not hesitate use `const` modifier. In other hand `volatile` modifier is not
recommended.
* New lines rules:
* One line after license header.
* One line between header group declaration (see above).
* Two lines after header declaration and before declaration at the end of a
file.
* One line after class and types forward declarations in headers.
* One line before each method modifiers (`public`, `public slots`, etc).
* Two lines between methods inside source code (`*.cpp`).
* One line after `qCDebug()` information (see below).
* One line inside a method to improve code reading.
* Each destructor should be virtual.
* Class constructor should have default arguments. Use `QObject *parent` property
for QObject based classes.
* QObject based classes constructors should have explicit modifier.
* Create one file (source and header) per class.
* `else if` construction is allowed and recommended.
* 'true ? foo : bar' construction is allowed and recommended for one-line assignment.
* Any global pointer should be assign to `nullptr` after deletion and before
initialization. Exception: if object is deleted into class destructor.
* Do not use semicolon in qml files unless it is required.
* Any method argument including class constructors should start with `_`.
Comments
--------
Please do not hesitate to use comments inside source code (especially in non-obvious
blocks). Comments also may use the following keywords:
* **TODO** - indicates that some new code should be implemented here later. Please
note that usually these methods should be implemented before the next release.
* **FIXME** - some dirty hacks and/or methods which should be done better.
* **HACK** - hacks inside code which requires to avoid some restrictions and/or
which adds additional non-obvious optimizations.
Do not use dots at the end of the comment line.
Development
-----------
* Officially the latest libraries versions should be used. In addition it is
possible to add workarounds for all versions (usually by using preprocessor
directives); in this case patches should be placed to `packages` directory.
* Build should not contain any warning.
* Try to minimize message in Release build with logging disabled. It is highly
recommended to fix KDE/Qt specific warning if possible
* Do not use dependency to KDE libraries if there are no any strictly necessary.
Exceptions are KNotification and KI18n libraries.
* It is highly recommended to use submodules for third party libraries if possible.
* The main branch is **development**. Changes in this branch may be merged to the
master one only if it is a 'stable' build.
* For experimental features development new branch `feature-foo` creation is allowed
and recommended.
* Experimental features should be added inside `BUILD_FUTURE` definition:
```
#ifdef BUILD_FUTURE
someTestFunctionInside();
#endif /* BUILD_FUTURE */
```
* Any project specific build variable should be mentioned inside `version.h` as
well.
* Recommended compiler is `clang`.
HIG
---
The recommended HIG is [KDE one](https://techbase.kde.org/Projects/Usability/HIG).
Avoid to paint interfaces inside plugin because QML and C++ parts may have different
theming.
Licensing
---------
All files should be licensed under GPLv3, the owner of the license should be the
project (i.e. **awesome-widgets**). See **Tools** section for more details.
Logging
-------
For logging please use [QLoggingCategory](http://doc.qt.io/qt-5/qloggingcategory.html).
Available categories should be declared in `awdebug.*` files. The following log
levels should be used:
* **debug** (`qCDebug()`) - method arguments information. Please note that it
is recommended to logging all arguments in the one line.
* **info** (`qCInfo()`) - additional information inside methods.
* **warning** (`qCWarning()`) - not critical information, which may be caused by
mistakes in configuration for example.
* **critical** (`qCCritical()`) - a critical error. After this error program may
be terminated.
The empty log string (e.g. `qCDebug();`) is not allowed because the method names
will be stripped by compiler with `Release` build type. To log class constructor
and destructor use `__PRETTY_FUNCTION__` macro.
Testing
-------
* Any changes should be tested by using `plasmawindowed` and `plasmashell` applications.
(It is also possible to use `plasmaengineexplorer` and `plasmoidviewer` in addition.)
* Any test should be performed on real (not Virtual Machine) system.
* Test builds should be:
1. `-DCMAKE_BUILD_TYPE=Debug`.
2. `-DCMAKE_BUILD_TYPE=Debug -DBUILD_TESTING=ON`.
3. `-DCMAKE_BUILD_TYPE=Release`.
* Additional test functions should be declated and used only inside `BUILD_TESTING`
definition.
Tools
-----
* For QString concatenation use `QString::arg` method.
* Any source file should have license header:
```
/***************************************************************************
* This file is part of awesome-widgets *
* *
* awesome-widgets is free software: you can redistribute it and/or *
* modify it under the terms of the GNU General Public License as *
* published by the Free Software Foundation, either version 3 of the *
* License, or (at your option) any later version. *
* *
* awesome-widgets is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with awesome-widgets. If not, see http://www.gnu.org/licenses/ *
***************************************************************************/
```
* Recommended class constructor for QObject based classes:
```
FooClass::FooClass(QObject *_parent, const QVariant _var)
: QObject(_parent)
, m_var(_var)
{
qCDebug(LOG_AW) << __PRETTY_FUNCTION__;
// some code below if any
}
```
* Property usage:
```
Q_PROPERTY(bool prop READ prop WRITE setProp);
public:
bool prop() const
{
return m_prop;
};
void setProp(const bool _prop)
{
// error checking if required
m_prop = _prop
}
private:
// declare with default value
bool m_prop = false;
```
* Use `cppcheck` to avoid common errors in the code. To start application just
run `make cppcheck`.
* Use `clang-format` to apply valid code format. To start application just run
`make clangformat`.