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Max Känner 2024-04-15 20:21:09 +02:00 committed by Max Känner
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.gitignore vendored Normal file
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# ---> Rust
# Generated by Cargo
# will have compiled files and executables
debug/
target/
# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
Cargo.lock
# These are backup files generated by rustfmt
**/*.rs.bk
# MSVC Windows builds of rustc generate these, which store debugging information
*.pdb
# Added by cargo
/target

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[package]
name = "macroconf"
version = "0.1.0"
edition = "2021"
description = "macro for creating configurations using miniconf"
license = "MIT OR Apache-2.0"
repository = "https://git.mkaenner.de/max/macroconf.git"
categories = ["config", "embedded", "data-structures"]
keywords = ["miniconf", "macro", "config"]
[lints.rust]
unsafe_code = "forbid"
[lints.clippy]
enum_glob_use = "deny"
pedantic = "deny"
nursery = "deny"
cargo = "warn"
[lib]
proc-macro = true
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
syn = { version = "2.0", features = ["full", "extra-traits"] }
proc-macro2 = "1.0"
quote = "1.0"
convert_case = "0.6.0"

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Copyright 2024 Max Känner
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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# lib-rs
Template for rust libraries

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src/lib.rs Normal file
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use std::iter::once;
use convert_case::{Case, Casing};
use proc_macro::TokenStream;
use proc_macro2::{Span as Span2, TokenStream as TokenStream2};
use quote::{format_ident, quote};
use syn::{
parse_macro_input, parse_quote, Attribute, DataStruct, DeriveInput, Expr, ExprLit, Field,
Ident, Lit, Type, Visibility,
};
/// Creates structs for the values to extend them with extra metadata.
///
/// supported metadata is `min`, `max` and `default`. Doc comments are parsed as `description`
///
/// # Panics
///
/// Panics if it is unable to generate a config struct from the input
#[proc_macro_attribute]
pub fn config(_attr: TokenStream, item: TokenStream) -> TokenStream {
let mut input = parse_macro_input!(item as DeriveInput);
let mut new_types = vec![];
match input.data {
syn::Data::Struct(DataStruct {
struct_token: _,
ref mut fields,
semi_token: _,
}) => {
for field in fields.iter_mut() {
if let Some(new_type) = generate_helper_struct(field, &input.ident, &input.vis) {
new_types.push(new_type);
}
}
}
syn::Data::Enum(_) => panic!("Enums are not supported"),
syn::Data::Union(_) => panic!("Unions are not supported"),
}
quote! {
#input
#(#new_types)*
}
.into()
}
fn generate_helper_struct(
field: &mut Field,
input_ident: &Ident,
input_visibility: &Visibility,
) -> Option<TokenStream2> {
let ty = field.ty.clone();
let new_type_ident = format_ident!(
"__{}{}",
input_ident,
field
.ident
.as_ref()
.map_or("Value".to_owned(), |v| v.to_string().to_case(Case::Pascal))
);
let mut new_type_impls = TokenStream2::new();
let mut new_type_miniconf_names = vec![];
let mut new_type_miniconf_consts = vec![];
let mut extra_new_checks = TokenStream2::new();
let mut generate_new_type = false;
for attr in &field.attrs {
if let Some((new_type_impl, new_check, const_ident, key)) =
parse_min(&new_type_ident, attr, &ty)
{
new_type_impls.extend(new_type_impl);
new_type_miniconf_consts.push(const_ident);
new_type_miniconf_names.push(key);
extra_new_checks.extend(new_check);
generate_new_type = true;
}
if let Some((new_type_impl, new_check, const_ident, key)) =
parse_max(&new_type_ident, attr, &ty)
{
new_type_impls.extend(new_type_impl);
new_type_miniconf_consts.push(const_ident);
new_type_miniconf_names.push(key);
extra_new_checks.extend(new_check);
generate_new_type = true;
}
if let Some((new_type_impl, const_ident, key)) = parse_default(&new_type_ident, attr, &ty) {
new_type_impls.extend(new_type_impl);
new_type_miniconf_consts.push(const_ident);
new_type_miniconf_names.push(key);
generate_new_type = true;
}
if let Some((new_type_impl, const_ident, key)) = parse_description(&new_type_ident, attr) {
new_type_impls.extend(new_type_impl);
new_type_miniconf_consts.push(const_ident);
new_type_miniconf_names.push(key);
}
}
if !generate_new_type {
return None;
}
field.attrs.retain(|attr| {
!["min", "max", "default"]
.iter()
.any(|key| attr.path().is_ident(key))
});
field.attrs.push(parse_quote!(#[tree(depth(1))]));
let vis = if matches!(field.vis, Visibility::Public(_))
|| matches!(field.vis, Visibility::Inherited)
{
input_visibility
} else {
&field.vis
};
field.ty = parse_quote!(#new_type_ident);
let miniconf_fields = new_type_miniconf_names.len() + 1;
let new = generate_new(&new_type_ident, &ty, &extra_new_checks);
let serde = generate_serde(&new_type_ident, &ty, !extra_new_checks.is_empty());
let tree_key = generate_tree_key(&new_type_ident, new_type_miniconf_names.iter());
let tree_serialize = generate_tree_serialize(&new_type_ident, &new_type_miniconf_consts[..]);
let tree_deserialize = generate_tree_deserialize(&new_type_ident, miniconf_fields);
Some(quote! {
#[allow(clippy::derive_partial_eq_without_eq)]
#[derive(Debug, PartialEq, PartialOrd, Clone, Copy)]
#vis struct #new_type_ident(#ty);
#new_type_impls
#new
#serde
#tree_key
#tree_serialize
#tree_deserialize
})
}
fn parse_min(
ident: &Ident,
attr: &Attribute,
ty: &Type,
) -> Option<(TokenStream2, Option<TokenStream2>, Ident, &'static str)> {
const KEY: &str = "min";
if !attr.path().is_ident(KEY) {
return None;
}
let const_ident = Ident::new(KEY.to_case(Case::Upper).as_str(), Span2::mixed_site());
let (value, new_check) = attr.meta.require_path_only().map_or_else(
|_| {
let value = &attr.meta.require_name_value().unwrap().value;
(
quote!(#value),
Some(quote! {
if (value < Self::#const_ident.0) {
return None;
}
}),
)
},
|_| (quote!(#ty::#const_ident), None),
);
let impl_quote = quote! {
impl #ident {
const #const_ident: Self = Self(#value);
}
};
Some((impl_quote, new_check, const_ident, KEY))
}
fn parse_max(
ident: &Ident,
attr: &Attribute,
ty: &Type,
) -> Option<(TokenStream2, Option<TokenStream2>, Ident, &'static str)> {
const KEY: &str = "max";
if !attr.path().is_ident(KEY) {
return None;
}
let const_ident = Ident::new(KEY.to_case(Case::Upper).as_str(), Span2::mixed_site());
let (value, new_check) = attr.meta.require_path_only().map_or_else(
|_| {
let value = &attr.meta.require_name_value().unwrap().value;
(
quote!(#value),
Some(quote! {
if (value > Self::#const_ident.0) {
return None;
}
}),
)
},
|_| (quote!(#ty::#const_ident), None),
);
let impl_quote = quote! {
impl #ident {
const #const_ident: Self = Self(#value);
}
};
Some((impl_quote, new_check, const_ident, KEY))
}
fn parse_default(
ident: &Ident,
attr: &Attribute,
ty: &Type,
) -> Option<(TokenStream2, Ident, &'static str)> {
const KEY: &str = "default";
if !attr.path().is_ident(KEY) {
return None;
}
let const_ident = Ident::new(KEY.to_case(Case::Upper).as_str(), Span2::mixed_site());
let value = attr.meta.require_path_only().map_or_else(
|_| {
let value = &attr.meta.require_name_value().unwrap().value;
quote!(#value)
},
|_| quote!(#ty::#const_ident),
);
let impl_quote = quote! {
impl #ident {
const #const_ident: Self = Self(#value);
}
impl ::core::default::Default for #ident {
fn default() -> Self {
Self::#const_ident
}
}
};
Some((impl_quote, const_ident, KEY))
}
fn parse_description(
ident: &Ident,
attr: &Attribute,
) -> Option<(TokenStream2, Ident, &'static str)> {
const KEY: &str = "description";
if !attr.path().is_ident("doc") {
return None;
}
let const_ident = Ident::new(KEY.to_case(Case::Upper).as_str(), Span2::mixed_site());
let value = &attr.meta.require_name_value().ok()?.value;
let value = match value {
Expr::Lit(ExprLit {
attrs: _,
lit: Lit::Str(ref string),
}) => string.value(),
_ => panic!("doc comment must be a string"),
};
let trimmed_value = value.trim();
let impl_quote = quote! {
impl #ident {
const #const_ident: &'static str = #trimmed_value;
}
};
Some((impl_quote, const_ident, KEY))
}
fn generate_new(ident: &Ident, ty: &Type, extra_checks: &TokenStream2) -> TokenStream2 {
if extra_checks.is_empty() {
quote! {
impl #ident {
pub const fn new(value: #ty) -> Self {
Self(value)
}
}
impl ::core::ops::Deref for #ident {
type Target = #ty;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl ::core::ops::DerefMut for #ident {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
}
} else {
let const_new = if [
parse_quote!(u8),
parse_quote!(u16),
parse_quote!(u32),
parse_quote!(u64),
parse_quote!(u128),
parse_quote!(i8),
parse_quote!(i16),
parse_quote!(i32),
parse_quote!(i64),
parse_quote!(i128),
]
.contains(ty)
{
Some(quote!(const))
} else {
None
};
quote! {
impl #ident {
pub #const_new fn new(value: #ty) -> ::core::option::Option<Self> {
#extra_checks
::core::option::Option::Some(Self(value))
}
#[allow(dead_code)]
const unsafe fn new_unchecked(value: #ty) -> Self {
Self(value)
}
}
impl ::core::ops::Deref for #ident {
type Target = #ty;
fn deref(&self) -> &Self::Target {
&self.0
}
}
}
}
}
fn generate_serde(ident: &Ident, ty: &Type, checked_new: bool) -> TokenStream2 {
let conversion = if checked_new {
quote! {
Self::new(value).ok_or_else(|| {
D::Error::custom("checking value bounds")
})
}
} else {
quote! {
Ok(Self::new(value))
}
};
quote! {
impl ::serde::Serialize for #ident {
fn serialize<S>(&self, serializer: S) -> ::core::result::Result<S::Ok, S::Error>
where
S: ::serde::Serializer,
{
self.0.serialize(serializer)
}
}
impl<'de> ::serde::Deserialize<'de> for #ident {
fn deserialize<D>(deserializer: D) -> ::core::result::Result<Self, D::Error>
where
D: ::serde::Deserializer<'de>,
{
type T = #ty;
let value = T::deserialize(deserializer)?;
#conversion
}
}
}
}
fn generate_tree_key<'a>(
ident: &Ident,
keys: impl Iterator<Item = &'a &'a str> + ExactSizeIterator + Clone,
) -> TokenStream2 {
let keys = once(&"value").chain(keys);
let num_keys = keys
.size_hint()
.1
.expect("safe because both iterators (once and original keys) are exact");
let max_length = keys.clone().map(|v| v.len()).max();
quote! {
impl #ident {
const __MINICONF_NAMES: [&'static str; #num_keys] = [#(#keys,)*];
}
impl ::miniconf::TreeKey<1> for #ident {
fn name_to_index(name: &str) -> ::core::option::Option<usize> {
Self::__MINICONF_NAMES.iter().position(|&n| n == name)
}
fn traverse_by_key<K, F, E>(mut keys: K, mut func: F) -> ::core::result::Result<usize, ::miniconf::Error<E>>
where
K: ::core::iter::Iterator,
K::Item: ::miniconf::Key,
// Writing this to return an iterator instead of using a callback
// would have worse performance (O(n^2) instead of O(n) for matching)
F: FnMut(usize, &str) -> ::core::result::Result<(), E>,
{
let ::core::option::Option::Some(key) = keys.next() else { return ::core::result::Result::Ok(0) };
let index = ::miniconf::Key::find::<1, Self>(&key).ok_or(::miniconf::Error::NotFound(1))?;
let name = Self::__MINICONF_NAMES
.get(index)
.ok_or(::miniconf::Error::NotFound(1))?;
func(index, name)?;
::miniconf::Increment::increment(::core::result::Result::Ok(0))
}
fn metadata() -> miniconf::Metadata {
let mut metadata = miniconf::Metadata::default();
metadata.max_depth = 1;
metadata.count = #num_keys;
metadata.max_length = #max_length;
metadata
}
}
}
}
fn generate_tree_serialize(ident: &Ident, consts: &[Ident]) -> TokenStream2 {
let matches = consts.iter().enumerate().map(|(i, ident)| {
let index = i + 1;
quote! {
#index => ::miniconf::Serialize::serialize(&Self::#ident, ser)?,
}
});
quote! {
impl ::miniconf::TreeSerialize<1> for #ident {
fn serialize_by_key<K, S>(
&self,
mut keys: K,
ser: S,
) -> ::core::result::Result<usize, ::miniconf::Error<S::Error>>
where
K: ::core::iter::Iterator,
K::Item: ::miniconf::Key,
S: ::serde::Serializer,
{
let ::core::option::Option::Some(key) = keys.next() else {
return ::miniconf::Increment::increment({
::miniconf::Serialize::serialize(&self.0, ser)?;
::core::result::Result::Ok(0)
});
};
let index = ::miniconf::Key::find::<1, Self>(&key).ok_or(miniconf::Error::NotFound(1))?;
if keys.next().is_some() {
return ::core::result::Result::Err(::miniconf::Error::TooLong(1));
}
::miniconf::Increment::increment({
match index {
0 => ::miniconf::Serialize::serialize(&self.0, ser)?,
#(#matches)*
_ => unreachable!(),
};
::core::result::Result::Ok(0)
})
}
}
}
}
fn generate_tree_deserialize(ident: &Ident, num_keys: usize) -> TokenStream2 {
quote! {
impl<'de> ::miniconf::TreeDeserialize<'de, 1> for #ident {
fn deserialize_by_key<K, D>(
&mut self,
mut keys: K,
de: D,
) -> ::core::result::Result<usize, ::miniconf::Error<D::Error>>
where
K: ::core::iter::Iterator,
K::Item: ::miniconf::Key,
D: ::serde::Deserializer<'de>,
{
let ::core::option::Option::Some(key) = keys.next() else {
self.0 = ::miniconf::Deserialize::deserialize(de)?;
return ::core::result::Result::Ok(0);
};
let index = ::miniconf::Key::find::<1, Self>(&key).ok_or(::miniconf::Error::NotFound(1))?;
if keys.next().is_some() {
return ::core::result::Result::Err(miniconf::Error::TooLong(1));
}
match index {
0 => ::miniconf::Increment::increment({
self.0 = ::miniconf::Deserialize::deserialize(de)?;
Ok(0)
}),
1..=#num_keys => ::core::result::Result::Err(::miniconf::Error::Absent(0)),
_ => unreachable!(),
}
}
}
}
}