1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128

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())),
            "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`].
#[allow(missing_docs)]
pub enum KnownCustom<'a> {
    Name(crate::NameSectionReader<'a>),
    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()
    }
}