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extern crate proc_macro;
#[macro_use] mod error;
mod gen;
use crate::error::{DeriveError, DeriveResult};
use crate::gen::InputType;
use proc_macro::TokenStream;
use proc_macro2::{TokenStream as TokenStream2};
#[cfg(feature = "dump-expansions--unstable")]
use proc_macro2::{Ident as Ident2};
use quote::quote;
#[cfg(feature = "dump-expansions--unstable")]
use std::fs::{remove_file, File, OpenOptions};
#[cfg(feature = "dump-expansions--unstable")]
use std::io::Write;
#[cfg(feature = "dump-expansions--unstable")]
use std::path::{Path, PathBuf};
use syn::{parse_macro_input, DeriveInput};
#[proc_macro_derive(Delta, attributes(delta))]
pub fn derive(input: TokenStream) -> TokenStream {
let input = parse_macro_input!(input as DeriveInput);
let output: TokenStream2 = derive_internal(input).unwrap(
);
TokenStream::from(output)
}
#[allow(non_snake_case)]
fn derive_internal(input: DeriveInput) -> DeriveResult<TokenStream2> {
let input_type: InputType = InputType::parse(&input)?;
let delta_type_definition = input_type.define_delta_type()?;
let impl_Debug = input_type.define_Debug_impl()?;
let impl_Core = input_type.define_Core_impl()?;
let impl_Apply = input_type.define_Apply_impl()?;
let impl_Delta = input_type.define_Delta_impl()?;
let impl_FromDelta = input_type.define_FromDelta_impl()?;
let impl_IntoDelta = input_type.define_IntoDelta_impl()?;
let output: TokenStream2 = quote! {
#delta_type_definition
#impl_Debug
#impl_Core
#impl_Apply
#impl_Delta
#impl_FromDelta
#impl_IntoDelta
};
#[cfg(feature = "print-expansions--unstable")]
print_generated_code(
&delta_type_definition,
&impl_Debug,
&impl_Core,
&impl_Apply,
&impl_Delta,
&impl_FromDelta,
&impl_IntoDelta,
);
#[cfg(feature = "dump-expansions--unstable")]
write_generated_code_to_file(
input_type.type_name()?,
&delta_type_definition,
&impl_Debug,
&impl_Core,
&impl_Apply,
&impl_Delta,
&impl_FromDelta,
&impl_IntoDelta,
);
Ok(output)
}
#[cfg(feature = "print-expansions--unstable")]
#[allow(unused, non_snake_case)]
fn print_generated_code(
delta_type_definition: &TokenStream2,
impl_Debug: &TokenStream2,
impl_Core: &TokenStream2,
impl_Apply: &TokenStream2,
impl_Delta: &TokenStream2,
impl_FromDelta: &TokenStream2,
impl_IntoDelta: &TokenStream2,
) {
println!("{}\n", delta_type_definition);
println!("{}\n", impl_Debug);
println!("{}\n", impl_Core);
println!("{}\n", impl_Apply);
println!("{}\n", impl_Delta);
println!("{}\n", impl_FromDelta);
println!("{}\n", impl_IntoDelta);
println!("\n\n\n\n");
}
#[cfg(feature = "dump-expansions--unstable")]
#[allow(unused, non_snake_case)]
fn write_generated_code_to_file(
type_name: &Ident2,
delta_type_definition: &TokenStream2,
impl_Debug: &TokenStream2,
impl_Core: &TokenStream2,
impl_Apply: &TokenStream2,
impl_Delta: &TokenStream2,
impl_FromDelta: &TokenStream2,
impl_IntoDelta: &TokenStream2,
) {
let manifest_dir: &Path = Path::new(env!("CARGO_MANIFEST_DIR"));
let expanded_dir: PathBuf = manifest_dir.join("expanded");
let filename: PathBuf = expanded_dir.join(&format!("{}.rs", type_name));
create_dir(&expanded_dir);
let _ = remove_file(&filename);
let mut file: File = open_file(&filename);
println!("wrote {}", filename.display());
file.write_all(format!("{}", delta_type_definition).as_bytes())
.expect("Failed to write delta_type_definition");
file.write_all("\n\n".as_bytes()).expect("Failed to write newlines");
file.write_all(format!("{}", impl_Debug).as_bytes())
.expect("Failed to write impl_Debug");
file.write_all("\n\n".as_bytes()).expect("Failed to write newlines");
file.write_all(format!("{}", impl_Core).as_bytes())
.expect("Failed to write impl_Core");
file.write_all("\n\n".as_bytes()).expect("Failed to write newlines");
file.write_all(format!("{}", impl_Apply).as_bytes())
.expect("Failed to write impl_Apply");
file.write_all("\n\n".as_bytes()).expect("Failed to write newlines");
file.write_all(format!("{}", impl_Delta).as_bytes())
.expect("Failed to write impl_Delta");
file.write_all("\n\n".as_bytes()).expect("Failed to write newlines");
file.write_all(format!("{}", impl_FromDelta).as_bytes())
.expect("Failed to write impl_FromDelta");
file.write_all("\n\n".as_bytes()).expect("Failed to write newlines");
file.write_all(format!("{}", impl_IntoDelta).as_bytes())
.expect("Failed to write impl_IntoDelta");
file.write_all("\n\n".as_bytes()).expect("Failed to write newlines");
file.flush().expect(&format!("Failed to flush {}", filename.display()));
std::process::Command::new("rustfmt")
.args(&[
"--emit", "files", "--edition", "2018",
&format!("{}", filename.display())
])
.output()
.expect("failed to execute rustfmt;");
}
#[cfg(feature = "dump-expansions--unstable")]
fn create_dir<P: AsRef<Path>>(path: P) {
let path = path.as_ref();
std::fs::DirBuilder::new()
.recursive(true)
.create(path)
.expect(&format!("Failed to create dir {}", path.display()));
}
#[cfg(feature = "dump-expansions--unstable")]
fn open_file<P: AsRef<Path>>(path: P) -> File {
let path = path.as_ref();
OpenOptions::new()
.create_new(true)
.write(true)
.truncate(true)
.open(path)
.expect(&format!("Failed to open {}", path.display()))
}