wasm_metadata/
payload.rs

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
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
use std::ops::Range;

use anyhow::Result;
use serde_derive::Serialize;
use wasmparser::{KnownCustom, Parser, Payload::*};

use crate::{
    Author, ComponentNames, Description, Homepage, Licenses, Metadata, ModuleNames, Producers,
    Revision, Source,
};

/// Data representing either a Wasm Component or module
///
/// Each payload has additional [`Metadata`] associated with it,
/// but if it's a Component it may have also additional `Payloads` associated
/// with it.
#[derive(Debug, Serialize)]
#[serde(rename_all = "lowercase")]
pub enum Payload {
    /// A representation of a Wasm Component
    Component {
        /// The metadata associated with the Component
        metadata: Metadata,
        /// The metadata of nested Components or Modules
        children: Vec<Payload>,
    },
    /// A representation of a Wasm Module
    Module(Metadata),
}

impl Payload {
    /// Parse metadata from a WebAssembly binary. Supports both core WebAssembly modules, and
    /// WebAssembly components.
    pub fn from_binary(input: &[u8]) -> Result<Self> {
        let mut output = Vec::new();

        for payload in Parser::new(0).parse_all(&input) {
            match payload? {
                Version { encoding, .. } => {
                    if output.is_empty() {
                        match encoding {
                            wasmparser::Encoding::Module => {
                                output.push(Self::empty_module(0..input.len()))
                            }
                            wasmparser::Encoding::Component => {
                                output.push(Self::empty_component(0..input.len()))
                            }
                        }
                    }
                }
                ModuleSection {
                    unchecked_range: range,
                    ..
                } => output.push(Self::empty_module(range)),
                ComponentSection {
                    unchecked_range: range,
                    ..
                } => output.push(Self::empty_component(range)),
                End { .. } => {
                    let finished = output.pop().expect("non-empty metadata stack");
                    if output.is_empty() {
                        return Ok(finished);
                    } else {
                        output.last_mut().unwrap().push_child(finished);
                    }
                }
                CustomSection(c) => match c.as_known() {
                    KnownCustom::Name(_) => {
                        let names = ModuleNames::from_bytes(c.data(), c.data_offset())?;
                        if let Some(name) = names.get_name() {
                            output
                                .last_mut()
                                .expect("non-empty metadata stack")
                                .metadata_mut()
                                .name = Some(name.clone());
                        }
                    }
                    KnownCustom::ComponentName(_) => {
                        let names = ComponentNames::from_bytes(c.data(), c.data_offset())?;
                        if let Some(name) = names.get_name() {
                            output
                                .last_mut()
                                .expect("non-empty metadata stack")
                                .metadata_mut()
                                .name = Some(name.clone());
                        }
                    }
                    KnownCustom::Producers(_) => {
                        let producers = Producers::from_bytes(c.data(), c.data_offset())?;
                        output
                            .last_mut()
                            .expect("non-empty metadata stack")
                            .metadata_mut()
                            .producers = Some(producers);
                    }
                    KnownCustom::Unknown if c.name() == "author" => {
                        let a = Author::parse_custom_section(&c)?;
                        let Metadata { author, .. } = output
                            .last_mut()
                            .expect("non-empty metadata stack")
                            .metadata_mut();
                        *author = Some(a);
                    }
                    KnownCustom::Unknown if c.name() == "description" => {
                        let a = Description::parse_custom_section(&c)?;
                        let Metadata { description, .. } = output
                            .last_mut()
                            .expect("non-empty metadata stack")
                            .metadata_mut();
                        *description = Some(a);
                    }
                    KnownCustom::Unknown if c.name() == "licenses" => {
                        let a = Licenses::parse_custom_section(&c)?;
                        let Metadata { licenses, .. } = output
                            .last_mut()
                            .expect("non-empty metadata stack")
                            .metadata_mut();
                        *licenses = Some(a);
                    }
                    KnownCustom::Unknown if c.name() == "source" => {
                        let a = Source::parse_custom_section(&c)?;
                        let Metadata { source, .. } = output
                            .last_mut()
                            .expect("non-empty metadata stack")
                            .metadata_mut();
                        *source = Some(a);
                    }
                    KnownCustom::Unknown if c.name() == "homepage" => {
                        let a = Homepage::parse_custom_section(&c)?;
                        let Metadata { homepage, .. } = output
                            .last_mut()
                            .expect("non-empty metadata stack")
                            .metadata_mut();
                        *homepage = Some(a);
                    }
                    KnownCustom::Unknown if c.name() == "revision" => {
                        let a = Revision::parse_custom_section(&c)?;
                        let Metadata { revision, .. } = output
                            .last_mut()
                            .expect("non-empty metadata stack")
                            .metadata_mut();
                        *revision = Some(a);
                    }
                    KnownCustom::Unknown if c.name() == "version" => {
                        let a = crate::Version::parse_custom_section(&c)?;
                        let Metadata { version, .. } = output
                            .last_mut()
                            .expect("non-empty metadata stack")
                            .metadata_mut();
                        *version = Some(a);
                    }
                    _ => {}
                },
                _ => {}
            }
        }
        Err(anyhow::anyhow!(
            "malformed wasm binary, should have reached end"
        ))
    }

    /// Get a reference te the metadata
    pub fn metadata(&self) -> &Metadata {
        match self {
            Payload::Component { metadata, .. } => metadata,
            Payload::Module(metadata) => metadata,
        }
    }

    /// Get a mutable reference te the metadata
    pub fn metadata_mut(&mut self) -> &mut Metadata {
        match self {
            Payload::Component { metadata, .. } => metadata,
            Payload::Module(metadata) => metadata,
        }
    }

    fn empty_component(range: Range<usize>) -> Self {
        let mut this = Self::Component {
            metadata: Metadata::default(),
            children: vec![],
        };
        this.metadata_mut().range = range;
        this
    }

    fn empty_module(range: Range<usize>) -> Self {
        let mut this = Self::Module(Metadata::default());
        this.metadata_mut().range = range;
        this
    }

    fn push_child(&mut self, child: Self) {
        match self {
            Self::Module { .. } => panic!("module shouldnt have children"),
            Self::Component { children, .. } => children.push(child),
        }
    }
}