C++ style guide

The Fuchsia project follows the Google C++ style guide, with a few exceptions.

By policy, code should be formatted by clang-format which should handle many decisions.

Exceptions

Braces

Always use braces { } when the contents of a block are more than one line. This is something you need to watch since Clang-format doesn't know to add these.

// Don't do this.
while (!done)
  doSomethingWithAReallyLongLine(
       wrapped_arg);

// Correct.
while (!done) {
  doSomethingWithAReallyLongLine(
       wrapped_arg);
}

Conditionals and loops

Do not use spaces inside parentheses (the Google style guide discourages but permits this).

Do not use the single-line form for short conditionals and loops (the Google style guide permits both forms):

// Don't do this:
if (x == kFoo) return new Foo();

// Correct.
if (x == kFoo)
  return new Foo;

Namespace Names

Nested namespaces are forbidden, with the following exceptions:
- internal (when required to hide implementation details of templated code)
- code generated by the FIDL compiler
The following top-level namespaces are forbidden:
- internal
- fuchsia (except in code generated by the FIDL compiler)
Namespaces in SDK libraries must be kept to as short a list as possible. A later document will provide an explicit list of allowed namespaces; in the meantime, new namespaces should be introduced thoughtfully.
Namespaces in non-SDK libraries should also be chosen so as to reduce the risk of clashes. Very generic nouns (eg. media) are best avoided.

Rationale: Tip of the Week #130: Namespace Naming

`#include`s

#includes use either <angle brackets> or "quotes" depending on context.

Use "" if the path is from the root of the source tree (e.g. "garnet/foo/bar/baz.h") or if the include is in the same directory as the includer (e.g. "baz.h").
Use <> otherwise, which typically means the header is a “public” header of some sort (e.g. <lib/foo/bar.h> or <zircon/foo.h>).