wasm_encoder/core/
imports.rs

1use crate::{
2    encode_section, Encode, GlobalType, MemoryType, Section, SectionId, TableType, TagType,
3    CORE_FUNCTION_SORT, CORE_GLOBAL_SORT, CORE_MEMORY_SORT, CORE_TABLE_SORT, CORE_TAG_SORT,
4};
5use alloc::vec::Vec;
6
7/// The type of an entity.
8#[derive(Debug, Clone, Copy, PartialEq, Eq)]
9pub enum EntityType {
10    /// A function type.
11    ///
12    /// The value is an index into the types section.
13    Function(u32),
14    /// A table type.
15    Table(TableType),
16    /// A memory type.
17    Memory(MemoryType),
18    /// A global type.
19    Global(GlobalType),
20    /// A tag type.
21    ///
22    /// This variant is used with the exception handling proposal.
23    Tag(TagType),
24}
25
26impl Encode for EntityType {
27    fn encode(&self, sink: &mut Vec<u8>) {
28        match self {
29            Self::Function(i) => {
30                sink.push(CORE_FUNCTION_SORT);
31                i.encode(sink);
32            }
33            Self::Table(t) => {
34                sink.push(CORE_TABLE_SORT);
35                t.encode(sink);
36            }
37            Self::Memory(t) => {
38                sink.push(CORE_MEMORY_SORT);
39                t.encode(sink);
40            }
41            Self::Global(t) => {
42                sink.push(CORE_GLOBAL_SORT);
43                t.encode(sink);
44            }
45            Self::Tag(t) => {
46                sink.push(CORE_TAG_SORT);
47                t.encode(sink);
48            }
49        }
50    }
51}
52
53impl From<TableType> for EntityType {
54    fn from(t: TableType) -> Self {
55        Self::Table(t)
56    }
57}
58
59impl From<MemoryType> for EntityType {
60    fn from(t: MemoryType) -> Self {
61        Self::Memory(t)
62    }
63}
64
65impl From<GlobalType> for EntityType {
66    fn from(t: GlobalType) -> Self {
67        Self::Global(t)
68    }
69}
70
71impl From<TagType> for EntityType {
72    fn from(t: TagType) -> Self {
73        Self::Tag(t)
74    }
75}
76
77/// An encoder for the import section of WebAssembly modules.
78///
79/// # Example
80///
81/// ```rust
82/// use wasm_encoder::{MemoryType, Module, ImportSection};
83///
84/// let mut imports = ImportSection::new();
85/// imports.import(
86///     "env",
87///     "memory",
88///     MemoryType {
89///         minimum: 1,
90///         maximum: None,
91///         memory64: false,
92///         shared: false,
93///         page_size_log2: None,
94///     }
95/// );
96///
97/// let mut module = Module::new();
98/// module.section(&imports);
99///
100/// let bytes = module.finish();
101/// ```
102#[derive(Clone, Debug, Default)]
103pub struct ImportSection {
104    bytes: Vec<u8>,
105    num_added: u32,
106}
107
108impl ImportSection {
109    /// Create a new import section encoder.
110    pub fn new() -> Self {
111        Self::default()
112    }
113
114    /// The number of imports in the section.
115    pub fn len(&self) -> u32 {
116        self.num_added
117    }
118
119    /// Determines if the section is empty.
120    pub fn is_empty(&self) -> bool {
121        self.num_added == 0
122    }
123
124    /// Define an import in the import section.
125    pub fn import(&mut self, module: &str, field: &str, ty: impl Into<EntityType>) -> &mut Self {
126        module.encode(&mut self.bytes);
127        field.encode(&mut self.bytes);
128        ty.into().encode(&mut self.bytes);
129        self.num_added += 1;
130        self
131    }
132}
133
134impl Encode for ImportSection {
135    fn encode(&self, sink: &mut Vec<u8>) {
136        encode_section(sink, self.num_added, &self.bytes);
137    }
138}
139
140impl Section for ImportSection {
141    fn id(&self) -> u8 {
142        SectionId::Import.into()
143    }
144}
wasm_encoder/core/imports.rs

wasm_encoder/core/
imports.rs
