reminder-bot/regex_command_attr/src/structures.rs

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use crate::util::{Argument, Parenthesised};
use proc_macro2::Span;
use proc_macro2::TokenStream as TokenStream2;
use quote::{quote, ToTokens};
use syn::{
braced,
parse::{Error, Parse, ParseStream, Result},
spanned::Spanned,
Attribute, Block, FnArg, Ident, Pat, Path, PathSegment, ReturnType, Stmt,
Token, Type, Visibility,
};
fn parse_argument(arg: FnArg) -> Result<Argument> {
match arg {
FnArg::Typed(typed) => {
let pat = typed.pat;
let kind = typed.ty;
match *pat {
Pat::Ident(id) => {
let name = id.ident;
let mutable = id.mutability;
Ok(Argument {
mutable,
name,
kind: *kind,
})
}
Pat::Wild(wild) => {
let token = wild.underscore_token;
let name = Ident::new("_", token.spans[0]);
Ok(Argument {
mutable: None,
name,
kind: *kind,
})
}
_ => Err(Error::new(
pat.span(),
format_args!("unsupported pattern: {:?}", pat),
)),
}
}
FnArg::Receiver(_) => Err(Error::new(
arg.span(),
format_args!("`self` arguments are prohibited: {:?}", arg),
)),
}
}
/// Test if the attribute is cooked.
fn is_cooked(attr: &Attribute) -> bool {
const COOKED_ATTRIBUTE_NAMES: &[&str] = &[
"cfg",
"cfg_attr",
"doc",
"derive",
"inline",
"allow",
"warn",
"deny",
"forbid",
];
COOKED_ATTRIBUTE_NAMES.iter().any(|n| attr.path.is_ident(n))
}
/// Removes cooked attributes from a vector of attributes. Uncooked attributes are left in the vector.
///
/// # Return
///
/// Returns a vector of cooked attributes that have been removed from the input vector.
fn remove_cooked(attrs: &mut Vec<Attribute>) -> Vec<Attribute> {
let mut cooked = Vec::new();
// FIXME: Replace with `Vec::drain_filter` once it is stable.
let mut i = 0;
while i < attrs.len() {
if !is_cooked(&attrs[i]) {
i += 1;
continue;
}
cooked.push(attrs.remove(i));
}
cooked
}
#[derive(Debug)]
pub struct CommandFun {
/// `#[...]`-style attributes.
pub attributes: Vec<Attribute>,
/// Populated cooked attributes. These are attributes outside of the realm of this crate's procedural macros
/// and will appear in generated output.
pub cooked: Vec<Attribute>,
pub visibility: Visibility,
pub name: Ident,
pub args: Vec<Argument>,
pub ret: Type,
pub body: Vec<Stmt>,
}
impl Parse for CommandFun {
fn parse(input: ParseStream<'_>) -> Result<Self> {
let mut attributes = input.call(Attribute::parse_outer)?;
// `#[doc = "..."]` is a cooked attribute but it is special-cased for commands.
for attr in &mut attributes {
// Rename documentation comment attributes (`#[doc = "..."]`) to `#[description = "..."]`.
if attr.path.is_ident("doc") {
attr.path = Path::from(PathSegment::from(Ident::new(
"description",
Span::call_site(),
)));
}
}
let cooked = remove_cooked(&mut attributes);
let visibility = input.parse::<Visibility>()?;
input.parse::<Token![async]>()?;
input.parse::<Token![fn]>()?;
let name = input.parse()?;
// (...)
let Parenthesised(args) = input.parse::<Parenthesised<FnArg>>()?;
let ret = match input.parse::<ReturnType>()? {
ReturnType::Type(_, t) => (*t).clone(),
ReturnType::Default => {
return Err(input
.error("expected a result type of either `CommandResult` or `CheckResult`"))
}
};
// { ... }
let bcont;
braced!(bcont in input);
let body = bcont.call(Block::parse_within)?;
let args = args
.into_iter()
.map(parse_argument)
.collect::<Result<Vec<_>>>()?;
Ok(Self {
attributes,
cooked,
visibility,
name,
args,
ret,
body,
})
}
}
impl ToTokens for CommandFun {
fn to_tokens(&self, stream: &mut TokenStream2) {
let Self {
attributes: _,
cooked,
visibility,
name,
args,
ret,
body,
} = self;
stream.extend(quote! {
#(#cooked)*
#visibility async fn #name (#(#args),*) -> #ret {
#(#body)*
}
});
}
}
#[derive(Debug)]
pub enum PermissionLevel {
Unrestricted,
Managed,
Restricted,
}
impl Default for PermissionLevel {
fn default() -> Self {
Self::Unrestricted
}
}
impl PermissionLevel {
pub fn from_str(s: &str) -> Option<Self> {
Some(match s.to_uppercase().as_str() {
"UNRESTRICTED" => Self::Unrestricted,
"MANAGED" => Self::Managed,
"RESTRICTED" => Self::Restricted,
_ => return None,
})
}
}
impl ToTokens for PermissionLevel {
fn to_tokens(&self, stream: &mut TokenStream2) {
let path = quote!(crate::framework::PermissionLevel);
let variant;
match self {
Self::Unrestricted => {
variant = quote!(Unrestricted);
}
Self::Managed => {
variant = quote!(Managed);
}
Self::Restricted => {
variant = quote!(Restricted);
}
}
stream.extend(quote! {
#path::#variant
});
}
}
#[derive(Debug, Default)]
pub struct Options {
pub permission_level: PermissionLevel,
pub supports_dm: bool,
pub can_blacklist: bool,
}
impl Options {
#[inline]
pub fn new() -> Self {
let mut options = Self::default();
options.can_blacklist = true;
options.supports_dm = true;
options
}
}