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check size of items

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This commit is contained in:
Florian Stecker
2024-03-01 13:31:34 -05:00
parent bc852d6b6a
commit b41547ddcb
4 changed files with 84 additions and 80 deletions
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90
btrfs_parse_derive/src/lib.rs
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@@ -1,9 +1,4 @@
extern crate proc_macro;
extern crate syn;
#[macro_use]
extern crate quote;
extern crate proc_macro2;
use quote::{quote, format_ident};
use proc_macro2::Span;
use proc_macro::TokenStream;
use syn::{DeriveInput, Data::Enum, parse_macro_input};
@@ -40,7 +35,7 @@ pub fn derive_parse_bin(input: TokenStream) -> TokenStream {
syn::Data::Struct(struct_item) => {
match struct_item.fields {
syn::Fields::Named(fields_named) => {
return derive_parse_bin_struct(&name, &fields_named.named);
derive_parse_bin_struct(&name, &fields_named.named)
},
syn::Fields::Unnamed(fields_unnamed) => {
if fields_unnamed.unnamed.len() != 1 {
@@ -48,13 +43,13 @@ pub fn derive_parse_bin(input: TokenStream) -> TokenStream {
}
let inner_type = fields_unnamed.unnamed.into_iter().next().unwrap().ty;
return derive_parse_bin_alias(name, inner_type);
derive_parse_bin_alias(name, inner_type)
},
_ => panic!("ParseBin on unit structs makes no sense!"),
}
},
_ => panic!("ParseBin only works on structs so far!"),
};
}
}
fn derive_parse_bin_alias(name: syn::Ident, ty: syn::Type) -> TokenStream {
@@ -113,49 +108,48 @@ fn derive_parse_bin_struct<'a, T>(name: &syn::Ident, fields: T) -> TokenStream
if let Some(varname) = veclen {
let field_name_item = format_ident!("{}_item", field_name);
let field_type_item: &syn::Type = match &field_type {
syn::Type::Path(tp) => {
match tp.path.segments.iter().next() {
Some(single) => {
if &single.ident.to_string() == "Vec" {
match &single.arguments {
syn::PathArguments::AngleBracketed(args) => {
match args.args.iter().next() {
Some(firstarg) => {
match firstarg {
syn::GenericArgument::Type(ty) => {
Some(ty)
},
_ => None,
}
},
None => None,
}
},
_ => None,
}
} else {
None
}
},
None => None,
}
},
_ => None,
}.expect("The len attribute is only allowed on type Vec<_>");
enum FieldType<'a> {
Vec(&'a syn::Type),
CString,
}
let syn::Type::Path(tp) = &field_type else { panic!() };
let single = tp.path.segments.iter().next().unwrap();
let field_type = if &single.ident.to_string() == "Vec" {
let syn::PathArguments::AngleBracketed(args) = &single.arguments else { panic!() };
let firstarg = args.args.iter().next().unwrap();
let syn::GenericArgument::Type(ty) = firstarg else { panic!() };
FieldType::Vec(ty)
} else if &single.ident.to_string() == "CString" {
FieldType::CString
} else {
panic!("The len attribute is only allowed on Vec<_> or CString")
};
let varname_ident = syn::Ident::new(&varname, Span::call_site());
parsing_statements.push(quote!{
let mut #field_name = Vec::new();
for i in 0 .. #varname_ident.0 as usize {
let #field_name_item = <#field_type_item>::parse_len(&bytes[__parse_bin_derive_size..])?;
__parse_bin_derive_size += #field_name_item.1;
#field_name.push(#field_name_item.0);
}
});
combining_expressions.push(quote!(#field_name: #field_name));
match field_type {
FieldType::Vec(field_type_item) => {
parsing_statements.push(quote!{
let mut #field_name = Vec::new();
for i in 0 .. #varname_ident.0 as usize {
let #field_name_item = <#field_type_item>::parse_len(&bytes[__parse_bin_derive_size..])?;
__parse_bin_derive_size += #field_name_item.1;
#field_name.push(#field_name_item.0);
}
});
combining_expressions.push(quote!(#field_name: #field_name));
},
FieldType::CString => {
parsing_statements.push(quote!{
let #field_name = CString::parse_len(&bytes[__parse_bin_derive_size .. __parse_bin_derive_size + #varname_ident.0 as usize])?;
__parse_bin_derive_size += #varname_ident.0 as usize;
});
combining_expressions.push(quote!(#field_name: #field_name.0));
},
}
} else {
parsing_statements.push(quote!{
let #field_name = <#field_type>::parse_len(&bytes[__parse_bin_derive_size..])?;