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use crate::{BinaryReader, Result};
use core::fmt;
use core::ops::Range;
/// A reader for custom sections of a WebAssembly module.
#[derive(Clone)]
pub struct CustomSectionReader<'a> {
name: &'a str,
reader: BinaryReader<'a>,
}
impl<'a> CustomSectionReader<'a> {
/// Constructs a new `CustomSectionReader` for the given data and offset.
pub fn new(mut reader: BinaryReader<'a>) -> Result<CustomSectionReader<'a>> {
let name = reader.read_string()?;
Ok(CustomSectionReader { name, reader })
}
/// The name of the custom section.
pub fn name(&self) -> &'a str {
self.name
}
/// The offset, relative to the start of the original module or component,
/// that the `data` payload for this custom section starts at.
pub fn data_offset(&self) -> usize {
self.reader.original_position()
}
/// The actual contents of the custom section.
pub fn data(&self) -> &'a [u8] {
self.reader.remaining_buffer()
}
/// The range of bytes that specify this whole custom section (including
/// both the name of this custom section and its data) specified in
/// offsets relative to the start of the byte stream.
pub fn range(&self) -> Range<usize> {
self.reader.range()
}
/// Attempts to match and see if this custom section is statically known to
/// `wasmparser` with any known section reader.
///
/// This will inspect `self.name()` and return a [`KnownCustom`] if the name
/// matches a known custom section where there is a parser available for it.
/// This can also be used as a convenience function for creating such
/// parsers.
///
/// If the custom section name is not known, or if a reader could not be
/// created, then `KnownCustom::Unknown` is returned.
pub fn as_known(&self) -> KnownCustom<'a> {
match self.name() {
"name" => KnownCustom::Name(crate::NameSectionReader::new(self.reader.shrink())),
#[cfg(feature = "component-model")]
"component-name" => KnownCustom::ComponentName(crate::ComponentNameSectionReader::new(
self.reader.shrink(),
)),
"metadata.code.branch_hint" => {
match crate::BranchHintSectionReader::new(self.reader.shrink()) {
Ok(s) => KnownCustom::BranchHints(s),
Err(_) => KnownCustom::Unknown,
}
}
"producers" => match crate::ProducersSectionReader::new(self.reader.shrink()) {
Ok(s) => KnownCustom::Producers(s),
Err(_) => KnownCustom::Unknown,
},
"dylink.0" => {
KnownCustom::Dylink0(crate::Dylink0SectionReader::new(self.reader.shrink()))
}
"core" => match crate::CoreDumpSection::new(self.reader.shrink()) {
Ok(s) => KnownCustom::CoreDump(s),
Err(_) => KnownCustom::Unknown,
},
"coremodules" => match crate::CoreDumpModulesSection::new(self.reader.shrink()) {
Ok(s) => KnownCustom::CoreDumpModules(s),
Err(_) => KnownCustom::Unknown,
},
"coreinstances" => match crate::CoreDumpInstancesSection::new(self.reader.shrink()) {
Ok(s) => KnownCustom::CoreDumpInstances(s),
Err(_) => KnownCustom::Unknown,
},
"corestack" => match crate::CoreDumpStackSection::new(self.reader.shrink()) {
Ok(s) => KnownCustom::CoreDumpStack(s),
Err(_) => KnownCustom::Unknown,
},
"linking" => match crate::LinkingSectionReader::new(self.reader.shrink()) {
Ok(s) => KnownCustom::Linking(s),
Err(_) => KnownCustom::Unknown,
},
s if s.starts_with("reloc.") => {
match crate::RelocSectionReader::new(self.reader.shrink()) {
Ok(s) => KnownCustom::Reloc(s),
Err(_) => KnownCustom::Unknown,
}
}
_ => KnownCustom::Unknown,
}
}
}
/// Return value of [`CustomSectionReader::as_known`].
///
/// Note that this is `#[non_exhaustive]` because depending on crate features
/// this enumeration will different entries.
#[allow(missing_docs)]
#[non_exhaustive]
pub enum KnownCustom<'a> {
Name(crate::NameSectionReader<'a>),
#[cfg(feature = "component-model")]
ComponentName(crate::ComponentNameSectionReader<'a>),
BranchHints(crate::BranchHintSectionReader<'a>),
Producers(crate::ProducersSectionReader<'a>),
Dylink0(crate::Dylink0SectionReader<'a>),
CoreDump(crate::CoreDumpSection<'a>),
CoreDumpStack(crate::CoreDumpStackSection<'a>),
CoreDumpInstances(crate::CoreDumpInstancesSection),
CoreDumpModules(crate::CoreDumpModulesSection<'a>),
Linking(crate::LinkingSectionReader<'a>),
Reloc(crate::RelocSectionReader<'a>),
Unknown,
}
impl<'a> fmt::Debug for CustomSectionReader<'a> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("CustomSectionReader")
.field("name", &self.name)
.field("data_offset", &self.data_offset())
.field("data", &"...")
.field("range", &self.range())
.finish()
}
}