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use crate::{encode_section, Encode, Section, SectionId};
/// An encoder for the tag section.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Module, TagSection, TagType, TagKind};
///
/// let mut tags = TagSection::new();
/// tags.tag(TagType {
/// kind: TagKind::Exception,
/// func_type_idx: 0,
/// });
///
/// let mut module = Module::new();
/// module.section(&tags);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Default, Debug)]
pub struct TagSection {
bytes: Vec<u8>,
num_added: u32,
}
impl TagSection {
/// Create a new tag section encoder.
pub fn new() -> Self {
Self::default()
}
/// The number of tags in the section.
pub fn len(&self) -> u32 {
self.num_added
}
/// Determines if the section is empty.
pub fn is_empty(&self) -> bool {
self.num_added == 0
}
/// Define a tag.
pub fn tag(&mut self, tag_type: TagType) -> &mut Self {
tag_type.encode(&mut self.bytes);
self.num_added += 1;
self
}
}
impl Encode for TagSection {
fn encode(&self, sink: &mut Vec<u8>) {
encode_section(sink, self.num_added, &self.bytes);
}
}
impl Section for TagSection {
fn id(&self) -> u8 {
SectionId::Tag.into()
}
}
/// Represents a tag kind.
#[repr(u8)]
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum TagKind {
/// The tag is an exception type.
Exception = 0x0,
}
#[cfg(feature = "wasmparser")]
impl From<wasmparser::TagKind> for TagKind {
fn from(kind: wasmparser::TagKind) -> Self {
match kind {
wasmparser::TagKind::Exception => TagKind::Exception,
}
}
}
/// A tag's type.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct TagType {
/// The kind of tag
pub kind: TagKind,
/// The function type this tag uses
pub func_type_idx: u32,
}
impl Encode for TagType {
fn encode(&self, sink: &mut Vec<u8>) {
sink.push(self.kind as u8);
self.func_type_idx.encode(sink);
}
}
#[cfg(feature = "wasmparser")]
impl From<wasmparser::TagType> for TagType {
fn from(tag_ty: wasmparser::TagType) -> Self {
TagType {
kind: tag_ty.kind.into(),
func_type_idx: tag_ty.func_type_idx,
}
}
}