rhai/codegen/src/module.rs

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use quote::{quote, ToTokens};
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use syn::{parse::Parse, parse::ParseStream};
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use crate::function::ExportedFn;
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use crate::rhai_module::ExportedConst;
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#[cfg(no_std)]
use alloc::vec as new_vec;
#[cfg(not(no_std))]
use std::vec as new_vec;
#[cfg(no_std)]
use core::mem;
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#[cfg(not(no_std))]
use std::mem;
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use std::borrow::Cow;
use crate::attrs::{AttrItem, ExportInfo, ExportScope, ExportedParams};
use crate::function::ExportedFnParams;
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#[derive(Debug, Clone, Eq, PartialEq, Hash, Default)]
pub(crate) struct ExportedModParams {
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pub name: String,
skip: bool,
pub scope: ExportScope,
}
impl Parse for ExportedModParams {
fn parse(args: ParseStream) -> syn::Result<Self> {
if args.is_empty() {
return Ok(ExportedModParams::default());
}
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let info = crate::attrs::parse_attr_items(args)?;
Self::from_info(info)
}
}
impl ExportedParams for ExportedModParams {
fn parse_stream(args: ParseStream) -> syn::Result<Self> {
Self::parse(args)
}
fn no_attrs() -> Self {
Default::default()
}
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fn from_info(info: ExportInfo) -> syn::Result<Self> {
let ExportInfo { items: attrs, .. } = info;
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let mut name = Default::default();
let mut skip = false;
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let mut scope = None;
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for attr in attrs {
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let AttrItem { key, value, .. } = attr;
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match (key.to_string().as_ref(), value) {
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("name", Some(s)) => {
let new_name = s.value();
if name == new_name {
return Err(syn::Error::new(key.span(), "conflicting name"));
}
name = new_name;
}
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("name", None) => return Err(syn::Error::new(key.span(), "requires value")),
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("skip", None) => skip = true,
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("skip", Some(s)) => return Err(syn::Error::new(s.span(), "extraneous value")),
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("export_prefix", Some(_)) | ("export_all", None) if scope.is_some() => {
return Err(syn::Error::new(key.span(), "duplicate export scope"));
}
("export_prefix", Some(s)) => scope = Some(ExportScope::Prefix(s.value())),
("export_prefix", None) => {
return Err(syn::Error::new(key.span(), "requires value"))
}
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("export_all", None) => scope = Some(ExportScope::All),
("export_all", Some(s)) => {
return Err(syn::Error::new(s.span(), "extraneous value"))
}
(attr, _) => {
return Err(syn::Error::new(
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key.span(),
format!("unknown attribute '{}'", attr),
))
}
}
}
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Ok(ExportedModParams {
name,
skip,
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scope: scope.unwrap_or_default(),
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..Default::default()
})
}
}
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#[derive(Debug)]
pub(crate) struct Module {
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mod_all: syn::ItemMod,
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fns: Vec<ExportedFn>,
consts: Vec<ExportedConst>,
submodules: Vec<Module>,
params: ExportedModParams,
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}
impl Module {
pub fn set_params(&mut self, params: ExportedModParams) -> syn::Result<()> {
self.params = params;
Ok(())
}
}
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impl Parse for Module {
fn parse(input: ParseStream) -> syn::Result<Self> {
let mut mod_all: syn::ItemMod = input.parse()?;
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let fns: Vec<_>;
let mut consts: Vec<_> = new_vec![];
let mut submodules: Vec<_> = Vec::new();
if let Some((_, ref mut content)) = mod_all.content {
// Gather and parse functions.
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fns = content
.iter_mut()
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.filter_map(|item| match item {
syn::Item::Fn(f) => Some(f),
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_ => None,
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})
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.try_fold(Vec::new(), |mut vec, itemfn| {
// #[cfg] attributes are not allowed on functions
crate::attrs::deny_cfg_attr(&itemfn.attrs)?;
let params: ExportedFnParams =
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match crate::attrs::inner_item_attributes(&mut itemfn.attrs, "rhai_fn") {
Ok(p) => p,
Err(e) => return Err(e),
};
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syn::parse2::<ExportedFn>(itemfn.to_token_stream())
.and_then(|mut f| {
f.set_params(params)?;
Ok(f)
})
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.map(|f| vec.push(f))
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.map(|_| vec)
})?;
// Gather and parse constants definitions.
for item in content.iter() {
match item {
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syn::Item::Const(syn::ItemConst {
vis,
ref expr,
ident,
attrs,
ty,
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..
}) => {
// #[cfg] attributes are not allowed on const declarations
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crate::attrs::deny_cfg_attr(&attrs)?;
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if let syn::Visibility::Public(_) = vis {
consts.push((ident.to_string(), ty.clone(), expr.as_ref().clone()));
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}
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}
_ => {}
}
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}
// Gather and parse submodule definitions.
//
// They are actually removed from the module's body, because they will need
// re-generating later when generated code is added.
submodules.reserve(content.len() - fns.len() - consts.len());
let mut i = 0;
while i < content.len() {
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if let syn::Item::Mod(_) = &content[i] {
let mut itemmod = match content.remove(i) {
syn::Item::Mod(m) => m,
_ => unreachable!(),
};
let params: ExportedModParams =
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match crate::attrs::inner_item_attributes(&mut itemmod.attrs, "rhai_mod") {
Ok(p) => p,
Err(e) => return Err(e),
};
let module =
syn::parse2::<Module>(itemmod.to_token_stream()).and_then(|mut m| {
m.set_params(params)?;
Ok(m)
})?;
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submodules.push(module);
} else {
i += 1;
}
}
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} else {
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fns = new_vec![];
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}
Ok(Module {
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mod_all,
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fns,
consts,
submodules,
params: ExportedModParams::default(),
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})
}
}
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#[allow(dead_code)]
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impl Module {
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pub fn attrs(&self) -> &Vec<syn::Attribute> {
&self.mod_all.attrs
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}
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pub fn module_name(&self) -> &syn::Ident {
&self.mod_all.ident
}
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pub fn exported_name(&self) -> Cow<str> {
if !self.params.name.is_empty() {
self.params.name.as_str().into()
} else {
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self.module_name().to_string().into()
}
}
pub fn update_scope(&mut self, parent_scope: &ExportScope) {
let keep = match (self.params.skip, parent_scope) {
(true, _) => false,
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(_, ExportScope::PubOnly) => matches!(self.mod_all.vis, syn::Visibility::Public(_)),
(_, ExportScope::Prefix(s)) => self.mod_all.ident.to_string().starts_with(s),
(_, ExportScope::All) => true,
};
self.params.skip = !keep;
}
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pub fn skipped(&self) -> bool {
self.params.skip
}
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pub fn generate(self) -> proc_macro2::TokenStream {
match self.generate_inner() {
Ok(tokens) => tokens,
Err(e) => e.to_compile_error(),
}
}
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fn generate_inner(self) -> Result<proc_macro2::TokenStream, syn::Error> {
// Check for collisions if the "name" attribute was used on inner functions.
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crate::rhai_module::check_rename_collisions(&self.fns)?;
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// Extract the current structure of the module.
let Module {
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mut mod_all,
mut fns,
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consts,
mut submodules,
params,
..
} = self;
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let mod_name = mod_all.ident.clone();
let (_, orig_content) = mod_all.content.take().unwrap();
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let mod_attrs = mem::take(&mut mod_all.attrs);
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if !params.skip {
// Generate new module items.
//
// This is done before inner module recursive generation, because that is destructive.
let mod_gen = crate::rhai_module::generate_body(
&mut fns,
&consts,
&mut submodules,
&params.scope,
);
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// NB: submodules must have their new items for exporting generated in depth-first order
// to avoid issues caused by re-parsing them
let inner_modules: Vec<proc_macro2::TokenStream> = submodules.drain(..)
.try_fold::<Vec<proc_macro2::TokenStream>, _,
Result<Vec<proc_macro2::TokenStream>, syn::Error>>(
Vec::new(), |mut acc, m| { acc.push(m.generate_inner()?); Ok(acc) })?;
// Regenerate the module with the new content added.
Ok(quote! {
#(#mod_attrs)*
pub mod #mod_name {
#(#orig_content)*
#(#inner_modules)*
#mod_gen
}
})
} else {
// Regenerate the original module as-is.
Ok(quote! {
#(#mod_attrs)*
pub mod #mod_name {
#(#orig_content)*
}
})
}
}
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pub fn name(&self) -> &syn::Ident {
&self.mod_all.ident
}
pub fn consts(&self) -> &[ExportedConst] {
&self.consts
}
pub fn fns(&self) -> &[ExportedFn] {
&self.fns
}
pub fn submodules(&self) -> &[Module] {
&self.submodules
}
pub fn content(&self) -> Option<&Vec<syn::Item>> {
match self.mod_all {
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syn::ItemMod {
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content: Some((_, ref vec)),
..
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} => Some(vec),
_ => None,
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}
}
}