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use std::borrow::Cow;
use crate::{encoding_size, CustomSection, Encode, Section, SectionId};
/// An encoder for the custom `name` section.
///
/// # Example
///
/// ```
/// use wasm_encoder::{Module, NameSection, NameMap};
///
/// let mut names = NameSection::new();
/// names.module("the module name");
///
/// let mut function_names = NameMap::new();
/// function_names.append(0, "name of function 0");
/// function_names.append(1, "a better function");
/// function_names.append(3, "the best function");
/// names.functions(&function_names);
///
/// let mut module = Module::new();
/// module.section(&names);
///
/// let wasm_bytes = module.finish();
/// ```
#[derive(Clone, Debug, Default)]
pub struct NameSection {
bytes: Vec<u8>,
}
enum Subsection {
// Currently specified in the wasm spec's appendix
Module = 0,
Function = 1,
Local = 2,
// specified as part of the extended name section proposal
//
Label = 3,
Type = 4,
Table = 5,
Memory = 6,
Global = 7,
Element = 8,
Data = 9,
Field = 10,
Tag = 11,
}
impl NameSection {
/// Creates a new blank `name` custom section.
pub fn new() -> Self {
Self::default()
}
/// Appends a module name subsection to this section.
///
/// This will indicate that the name of the entire module should be the
/// `name` specified. Note that this should be encoded first before other
/// subsections.
pub fn module(&mut self, name: &str) {
let len = encoding_size(u32::try_from(name.len()).unwrap());
self.subsection_header(Subsection::Module, len + name.len());
name.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all functions in this wasm module.
///
/// Function names are declared in the `names` map provided where the index
/// in the map corresponds to the wasm index of the function. This section
/// should come after the module name subsection (if present) and before the
/// locals subsection (if present).
pub fn functions(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Function, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of locals within functions in this
/// wasm module.
///
/// This section should come after the function name subsection (if present)
/// and before the labels subsection (if present).
pub fn locals(&mut self, names: &IndirectNameMap) {
self.subsection_header(Subsection::Local, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of labels within functions in this
/// wasm module.
///
/// This section should come after the local name subsection (if present)
/// and before the type subsection (if present).
pub fn labels(&mut self, names: &IndirectNameMap) {
self.subsection_header(Subsection::Label, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all types in this wasm module.
///
/// This section should come after the label name subsection (if present)
/// and before the table subsection (if present).
pub fn types(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Type, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all tables in this wasm module.
///
/// This section should come after the type name subsection (if present)
/// and before the memory subsection (if present).
pub fn tables(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Table, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all memories in this wasm module.
///
/// This section should come after the table name subsection (if present)
/// and before the global subsection (if present).
pub fn memories(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Memory, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all globals in this wasm module.
///
/// This section should come after the memory name subsection (if present)
/// and before the element subsection (if present).
pub fn globals(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Global, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all elements in this wasm module.
///
/// This section should come after the global name subsection (if present)
/// and before the data subsection (if present).
pub fn elements(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Element, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all data in this wasm module.
///
/// This section should come after the element name subsection (if present)
/// and before the field subsection (if present).
pub fn data(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Data, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all tags in this wasm module.
///
/// This section should come after the data name subsection (if present).
pub fn tag(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Tag, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of fields within types in this
/// wasm module.
///
/// This section should come after the data name subsection (if present)
/// and before the tag subsection (if present).
pub fn fields(&mut self, names: &IndirectNameMap) {
self.subsection_header(Subsection::Field, names.size());
names.encode(&mut self.bytes);
}
/// Appends a subsection for the names of all tags in this wasm module.
///
/// This section should come after the field name subsection (if present).
pub fn tags(&mut self, names: &NameMap) {
self.subsection_header(Subsection::Tag, names.size());
names.encode(&mut self.bytes);
}
fn subsection_header(&mut self, id: Subsection, len: usize) {
self.bytes.push(id as u8);
len.encode(&mut self.bytes);
}
/// View the encoded section as a CustomSection.
pub fn as_custom<'a>(&'a self) -> CustomSection<'a> {
CustomSection {
name: "name".into(),
data: Cow::Borrowed(&self.bytes),
}
}
}
impl Encode for NameSection {
fn encode(&self, sink: &mut Vec<u8>) {
self.as_custom().encode(sink);
}
}
impl Section for NameSection {
fn id(&self) -> u8 {
SectionId::Custom.into()
}
}
/// A map used to name items in a wasm module, organized by naming each
/// individual index.
///
/// This is used in conjunction with [`NameSection::functions`] and simlar
/// methods.
#[derive(Clone, Debug, Default)]
pub struct NameMap {
bytes: Vec<u8>,
count: u32,
}
impl NameMap {
/// Creates a new empty `NameMap`.
pub fn new() -> NameMap {
NameMap {
bytes: vec![],
count: 0,
}
}
/// Adds a an entry where the item at `idx` has the `name` specified.
///
/// Note that indices should be appended in ascending order of the index
/// value. Each index may only be named once, but not all indices must be
/// named (e.g. `0 foo; 1 bar; 7 qux` is valid but `0 foo; 0 bar` is not).
/// Names do not have to be unique (e.g. `0 foo; 1 foo; 2 foo` is valid).
pub fn append(&mut self, idx: u32, name: &str) {
idx.encode(&mut self.bytes);
name.encode(&mut self.bytes);
self.count += 1;
}
pub(crate) fn size(&self) -> usize {
encoding_size(self.count) + self.bytes.len()
}
/// Returns whether no names have been added to this map.
pub fn is_empty(&self) -> bool {
self.count == 0
}
}
impl Encode for NameMap {
fn encode(&self, sink: &mut Vec<u8>) {
self.count.encode(sink);
sink.extend(&self.bytes);
}
}
/// A map used to describe names with two levels of indirection, as opposed to a
/// [`NameMap`] which has one level of indirection.
///
/// This naming map is used with [`NameSection::locals`], for example.
#[derive(Clone, Debug, Default)]
pub struct IndirectNameMap {
bytes: Vec<u8>,
count: u32,
}
impl IndirectNameMap {
/// Creates a new empty name map.
pub fn new() -> IndirectNameMap {
IndirectNameMap {
bytes: vec![],
count: 0,
}
}
/// Adds a new entry where the item at `idx` has sub-items named within
/// `names` as specified.
///
/// For example if this is describing local names then `idx` is a function
/// index where the indexes within `names` are local indices.
pub fn append(&mut self, idx: u32, names: &NameMap) {
idx.encode(&mut self.bytes);
names.encode(&mut self.bytes);
self.count += 1;
}
fn size(&self) -> usize {
encoding_size(self.count) + self.bytes.len()
}
}
impl Encode for IndirectNameMap {
fn encode(&self, sink: &mut Vec<u8>) {
self.count.encode(sink);
sink.extend(&self.bytes);
}
}