use crate::prelude::*;
use crate::{BinaryReader, Result, Subsection, Subsections, SymbolFlags};
use core::ops::Range;
/// Parser for the dynamic linking `dylink.0` custom section.
///
/// This format is currently defined upstream at
/// <
https://github.com/WebAssembly/tool-conventions/blob/main/DynamicLinking.md>.
pub type Dylink0SectionReader<'a> = Subsections<'a, Dylink0Subsection<'a>>;
const WASM_DYLINK_MEM_INFO: u8 = 1;
const WASM_DYLINK_NEEDED: u8 = 2;
const WASM_DYLINK_EXPORT_INFO: u8 = 3;
const WASM_DYLINK_IMPORT_INFO: u8 = 4;
/// Represents a `WASM_DYLINK_MEM_INFO` field
#[derive(Debug, Copy, Clone)]
pub struct MemInfo {
/// Size of the memory area the loader should reserve for the module, which
/// will begin at `env.__memory_base`.
pub memory_size: u32,
/// The required alignment of the memory area, in bytes, encoded as a power
/// of 2.
pub memory_alignment: u32,
/// Size of the table area the loader should reserve for the module, which
/// will begin at `env.__table_base`.
pub table_size: u32,
/// The required alignment of the table area, in elements, encoded as a
/// power of 2.
pub table_alignment: u32,
}
#[allow(missing_docs)]
#[derive(Debug)]
pub struct ExportInfo<'a> {
pub name: &'a str,
pub flags: SymbolFlags,
}
#[allow(missing_docs)]
#[derive(Debug)]
pub struct ImportInfo<'a> {
pub module: &'a str,
pub field: &'a str,
pub flags: SymbolFlags,
}
/// Possible subsections of the `dylink.0` custom section.
#[derive(Debug)]
#[allow(missing_docs)]
pub enum Dylink0Subsection<'a> {
MemInfo(MemInfo),
Needed(Vec<&'a str>),
ExportInfo(Vec<ExportInfo<'a>>),
ImportInfo(Vec<ImportInfo<'a>>),
Unknown {
ty: u8,
data: &'a [u8],
range: Range<usize>,
},
}
impl<'a> Subsection<'a> for Dylink0Subsection<'a> {
fn from_reader(id: u8, mut reader: BinaryReader<'a>) -> Result<Self> {
let data = reader.remaining_buffer();
let offset = reader.original_position();
Ok(match id {
WASM_DYLINK_MEM_INFO => Self::MemInfo(MemInfo {
memory_size: reader.read_var_u32()?,
memory_alignment: reader.read_var_u32()?,
table_size: reader.read_var_u32()?,
table_alignment: reader.read_var_u32()?,
}),
WASM_DYLINK_NEEDED => Self::Needed(
(0..reader.read_var_u32()?)
.map(|_| reader.read_string())
.collect::<Result<_, _>>()?,
),
WASM_DYLINK_EXPORT_INFO => Self::ExportInfo(
(0..reader.read_var_u32()?)
.map(|_| {
Ok(ExportInfo {
name: reader.read_string()?,
flags: reader.read()?,
})
})
.collect::<Result<_, _>>()?,
),
WASM_DYLINK_IMPORT_INFO => Self::ImportInfo(
(0..reader.read_var_u32()?)
.map(|_| {
Ok(ImportInfo {
module: reader.read_string()?,
field: reader.read_string()?,
flags: reader.read()?,
})
})
.collect::<Result<_, _>>()?,
),
ty => Self::Unknown {
ty,
data,
range: offset..offset + data.len(),
},
})
}
}
