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#![feature(proc_macro_span)]
extern crate proc_macro;
use std::fs::File;
use std::path::PathBuf;
use std::str::from_utf8;
use libflate::deflate::Encoder;
use proc_macro::{TokenStream};
use proc_macro2::{Literal, Span};
use quote::quote;
use syn::{Error, LitStr, Result};
#[proc_macro]
pub fn deflate_file(ts: TokenStream) -> TokenStream {
match inner(ts, false) {
Ok(ts) => ts.into(),
Err(err) => err.to_compile_error().into(),
}
}
#[proc_macro]
pub fn deflate_utf8_file(ts: TokenStream) -> TokenStream {
match inner(ts, true) {
Ok(ts) => ts.into(),
Err(err) => err.to_compile_error().into(),
}
}
fn inner(ts: TokenStream, utf8: bool) -> Result<impl Into<TokenStream>> {
let dir = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
let lit = syn::parse::<LitStr>(ts)?;
let path = PathBuf::from(lit.value());
let target = if path.is_relative() {
dir.join(path)
} else {
path
};
fn emap<E: std::fmt::Display>(error: E) -> Error {
Error::new(Span::call_site(), error)
}
let mut file = File::open(target).map_err(emap)?;
let mut encoder = Encoder::new(Vec::<u8>::new());
if utf8 {
use std::io::Write;
let mut vec = Vec::<u8>::new();
std::io::copy(&mut file, &mut vec).map_err(emap)?;
from_utf8(&vec).map_err(emap)?;
encoder.write_all(&vec).map_err(emap)?;
} else {
std::io::copy(&mut file, &mut encoder).map_err(emap)?;
}
let bytes = encoder.finish().into_result().map_err(emap)?;
let bytes = bytes.into_iter().map(|byte| Literal::u8_suffixed(byte));
let result = quote!(&[#(#bytes),*]);
Ok(result)
}