Coding Standard for the ANGLE Project

Google Style Guide

We generally use the [Google C++ Style Guide] (http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml) as a basis for our Coding Standard, however we will deviate from it in a few areas, as noted below.

Items marked {DEV} indicate a deviation from the Google guidelines. Items marked {DO} are reiterating points from the Google guidelines.

Before you upload code to Gerrit, use git cl format to auto-format your code. This will catch most of the trivial formatting errors and save you time.

Header Files

• We will use .h for C++ headers.
• {DEV} #define guards should be of the form: <PATH>_<FILE>_H_. (Compiler codebase is varied, including <PROJECT>_ makes the names excessively long).

Scoping

• {DO} avoid globally scoped variables, unless absolutely necessary.

Classes

• {DEV} Inherit (privately) from angle::NonCopyable helper class (defined in common/angleutils.h) to disable default copy and assignment operators.

Other C++ Features

• {DEV} all parameters passed by reference, except for STL containers (e.g. std::vector, std::list), must be labeled const. For return parameters other than STL containers, use a pointer.
• {DO} avoid use of default arguments.
• {DONT} use C++ exceptions, they are disabled in the builds and not caught.
• {DO} use nullptr (instead of 0 or NULL) for pointers.
• {DO} use size_t for loop iterators and size values.
• {DO} use uint8_t pointers instead of void pointers to denote binary data.
• {DO} use C++11 according to the [Chromium guide on C++11] (http://chromium-cpp.appspot.com/).

Naming

File Names

• {DEV} Filenames should be all lowercase and can include underscores (_). If the file is an implementation of a class, the filename may be capitalized the same as the major class.
• {DEV} We use .cpp (instead of .cc), .h and .inl (inlined files) for C++ files and headers.

Directory Names

• Directory names should be all lowercase, unless following an externally imposed capitalization (eg include/EGL, or src/libGLESv2, etc)

Variable Names

Use the following guidelines, they do deviate somewhat from the Google guidelines.

• class and type names: start with capital letter and use CamelCase.
• {DEV} class member variables: use an m prefix instead of trailing underscore and use CamelCase.
• global variables (if they must be used): use a g_ prefix.
• {DEV} variable names: start with lower case and use CamelCase (chosen for consistency)
• {DEV} function names: Member functions start with lower case and use CamelCase. Non-member functions start with capital letter and use CamelCase (chosen for consistency)
• Constants: start with a k and use CamelCase
• namespaces: use all lower case
• Enum Names - use class enums, and the values should be uppercase with underscores.
• macros: all uppercase with underscores
• exceptions to naming: use common sense!

Comments

• {DO} read and follow Google's recommendations.
• Each file must start with the following boilerplate notice:

//
//  Copyright (c) 2016 The ANGLE Project Authors. All rights reserved.
//  Use of this source code is governed by a BSD-style license that can be
//  found in the LICENSE file.
//

Formatting

• {DEV} Avoid excessively long lines. Please keep lines under 100 columns long.
• Use unix-style newlines.
• {DO} use only spaces. No tab characters. Configure your editor to emit spaces when you hit the TAB-key.
• {DEV} indent 4 spaces at a time.
• conditionals: place space outside the parenthesis. No spaces inside.
• switch statements: use the output of git cl format.
• class format(eg private, public, protected): indent by 2 spaces. Regular 4-space indent from the outer scope for declarations/definitions.
• pointers and references: * and & tight against the variable
• namespaces: are not indented.
• extern code blocks: are not indented.
• {DEV} braces should go on a separate line, except for functions defined in a header file where the whole function declaration and definition fit on one line.

Examples:

if (conditional)
{
    stuff();
}
else
{
    otherstuff()
}

switch (conditional)
{
  case foo:
    dostuff();
    break;
  case bar:
    otherstuff();
    break;
  default:
    WTFBBQ();
}

class MyClass : public Foo
{
  public:
    MyClass();
    ~MyClass() {};
  private:
    DISALLOW_COPY_AND_ASSIGN(MyClass);
};

char *c;
const string &str;

Exceptions to the Rules

• If modifying pre-existing code that does not match the standard, the altered portions of the code should be changed to match the standard.