You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

129 lines
3.3 KiB

//! The available formats to convert
use super::*;
use std::io;
use std::convert::TryFrom;
use object::Object;
/// `Format` impl for JSON.
pub mod json;
/// `Format` impl for S expressions.
pub mod sexpr;
/// `Format` impl for CBOR.
pub mod cbor;
use error::*;
pub mod config;
use config::*;
/// A directive for a format on how to encode and decode objects.
#[derive(Clone, Copy)]
pub struct FormatDirective
{
encode: fn (&Config, &mut dyn io::Write, &Object) -> Result<usize, Error>,
decode: fn (&Config, &mut dyn io::Read) -> Result<(Object, usize), Error>,
}
impl FormatDirective
{
/// Call the decode method of this directive
#[inline(always)] pub fn call_decode(&self, cfg: &Config, mut stream: impl io::Read) -> Result<(Object, usize), Error>
{
let call = self.decode;
call(cfg, &mut stream)
}
/// Call the encode method of this directive
#[inline(always)] pub fn call_encode(&self, cfg: &Config, mut stream: impl io::Write, obj: &Object) -> Result<usize, Error>
{
let call = self.encode;
call(cfg, &mut stream, obj)
}
}
/// Trait for statically implementing formatters to/from `Object`.
pub trait Format
{
fn encode<W: io::Write>(cfg: &Config, to: W, obj: &Object) -> Result<usize, ErrorKind>;
fn decode<R: io::Read>(cfg: &Config, from: R) -> Result<Object, ErrorKind>;
}
macro_rules! directive {
($($name:literal),+ => $encode:expr, $decode:expr) => {
(&[$($name),+], FormatDirective {
encode: $encode,
decode: $decode,
})
};
(for $fmt:path => $($name:literal),+) => {
directive!($($name),+ => |c, w, o| {
<$fmt as Format>::encode(c, w, o).map_err(Error::encode)
}, |c, r| {
let mut r = r.with_counter();
let obj = <$fmt as Format>::decode(c, &mut r).map_err(Error::decode)?;
Ok((obj, r.count()))
})
}
}
/// All format directives and their name(s)
pub static FORMATS: &[(&'static [&'static str], FormatDirective)] = &[
directive!(for json::JsonFormatter => "json", "js", "javascript"),
directive!(for sexpr::SExpressionFormatter => "s-expression", "sexpr", "lisp", "lexpr"),
directive!(for cbor::CborFormatter => "cbor"),
];
/// Directives in a lookup stream
pub static DIRECTIVES: &[&'static FormatDirective; 3] = &[
&FORMATS[0].1,
&FORMATS[1].1,
&FORMATS[2].1,
];
pub(crate) const FORMAT_KIND_JSON: u32 = FormatKind::Json as u32;
pub(crate) const FORMAT_KIND_SEXPR: u32 = FormatKind::SExpr as u32;
pub(crate) const FORMAT_KIND_CBOR: u32 = FormatKind::CBor as u32;
/// The formats available for conversion
#[derive(Debug, Clone, PartialEq, Eq, Hash, Copy, PartialOrd, Ord)]
#[repr(C)]
pub enum FormatKind
{
Json = 1,
SExpr = 2,
CBor = 3,
}
impl FormatKind
{
/// Get the directive for this format kind
#[inline] pub fn directive(&self) -> &FormatDirective
{
DIRECTIVES[u32::from(*self) as usize]
}
}
impl From<FormatKind> for u32
{
fn from(from: FormatKind) -> Self
{
from as Self
}
}
impl TryFrom<u32> for FormatKind
{
type Error = ErrorKind;
fn try_from(from: u32) -> Result<Self, Self::Error>
{
Ok(match from {
FORMAT_KIND_JSON => Self::Json,
FORMAT_KIND_SEXPR => Self::SExpr,
FORMAT_KIND_CBOR => Self::CBor,
_ => return Err(ErrorKind::UnknownFormat(from)),
})
}
}
//const _: &[u8; 0] = &[0u8; std::mem::size_of::<Error>()]; // Size of error type check (unboxed 56 -> boxed 16)