2.6 KiB
Conventions
In order to achieve our goal of wrapping libc code in idiomatic rust constructs with minimal performance overhead, we follow the following conventions.
Note that, thus far, not all the code follows these conventions and not all conventions we try to follow have been documented here. If you find an instance of either, feel free to remedy the flaw by opening a pull request with appropriate changes or additions.
Change Log
We follow the conventions laid out in Keep A CHANGELOG.
libc constants, functions and structs
We do not define integer constants ourselves, but use or reexport them from the libc crate.
We use the functions exported from libc instead of writing our own
extern declarations.
We use the struct definitions from libc internally instead of writing
our own. If we want to add methods to a libc type, we use the newtype pattern.
For example,
pub struct SigSet(libc::sigset_t);
impl SigSet {
...
}
When creating newtypes, we use Rust's CamelCase type naming convention.
Bitflags
Many C functions have flags parameters that are combined from constants using
bitwise operations. We represent the types of these parameters by types defined
using our libc_bitflags! macro, which is a convenience wrapper around the
bitflags! macro from the bitflags crate that brings in the
constant value from libc.
We name the type for a set of constants whose element's names start with FOO_
FooFlags.
For example,
libc_bitflags!{
pub struct ProtFlags: libc::c_int {
PROT_NONE;
PROT_READ;
PROT_WRITE;
PROT_EXEC;
#[cfg(any(target_os = "linux", target_os = "android"))]
PROT_GROWSDOWN;
#[cfg(any(target_os = "linux", target_os = "android"))]
PROT_GROWSUP;
}
}
Enumerations
We represent sets of constants that are intended as mutually exclusive arguments to parameters of functions by enumerations.
Structures Initialized by libc Functions
Whenever we need to use a libc function to properly initialize a
variable and said function allows us to use uninitialized memory, we use
std::mem::MaybeUninit when defining the variable. This
allows us to avoid the overhead incurred by zeroing or otherwise initializing
the variable.