fce_wit_parser/extractor/
wit.rs

1/*
2 * Copyright 2020 Fluence Labs Limited
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17use crate::custom::IT_SECTION_NAME;
18use crate::errors::WITParserError;
19use crate::Result;
20
21use walrus::IdsToIndices;
22use wasmer_wit::ast::Interfaces;
23use wasmer_core::Module as WasmerModule;
24
25use std::borrow::Cow;
26use std::path::Path;
27
28/// Extracts WIT section of provided Wasm binary and converts it to a string.
29pub fn extract_text_wit<P>(wasm_file_path: P) -> Result<String>
30where
31    P: AsRef<Path>,
32{
33    let module = walrus::ModuleConfig::new()
34        .parse_file(wasm_file_path)
35        .map_err(WITParserError::CorruptedWasmFile)?;
36
37    let raw_custom_section = extract_custom_section(&module)?;
38    let wit_section_bytes = raw_custom_section.as_ref();
39    let wit = extract_wit_from_bytes(wit_section_bytes)?;
40
41    Ok((&wit).to_string())
42}
43
44/// Extracts WIT section of provided Wasm binary and converts it to a FCEWITInterfaces.
45pub fn extract_wit_from_module(wasmer_module: &WasmerModule) -> Result<Interfaces<'_>> {
46    let wit_sections = wasmer_module
47        .custom_sections(IT_SECTION_NAME)
48        .ok_or(WITParserError::NoITSection)?;
49
50    if wit_sections.len() > 1 {
51        return Err(WITParserError::MultipleITSections);
52    }
53
54    extract_wit_from_bytes(&wit_sections[0])
55}
56
57pub fn extract_version_from_module(module: &walrus::Module) -> Result<semver::Version> {
58    let raw_custom_section = extract_custom_section(&module)?;
59    let wit_section_bytes = raw_custom_section.as_ref();
60    let wit = extract_wit_from_bytes(wit_section_bytes)?;
61
62    Ok(wit.version)
63}
64
65pub(crate) fn extract_wit_from_bytes(wit_section_bytes: &[u8]) -> Result<Interfaces<'_>> {
66    match wasmer_wit::decoders::binary::parse::<(&[u8], nom::error::ErrorKind)>(wit_section_bytes) {
67        Ok((remainder, wit)) if remainder.is_empty() => Ok(wit),
68        Ok(_) => Err(WITParserError::ITRemainderNotEmpty),
69        Err(e) => Err(WITParserError::CorruptedITSection(e.to_owned())),
70    }
71}
72
73pub(crate) fn extract_custom_section(module: &walrus::Module) -> Result<Cow<'_, [u8]>> {
74    let sections = module
75        .customs
76        .iter()
77        .filter(|(_, section)| section.name() == IT_SECTION_NAME)
78        .collect::<Vec<_>>();
79
80    if sections.is_empty() {
81        return Err(WITParserError::NoITSection);
82    }
83    if sections.len() > 1 {
84        return Err(WITParserError::MultipleITSections);
85    }
86
87    let default_ids = IdsToIndices::default();
88    Ok(sections[0].1.data(&default_ids))
89}
fce_wit_parser/extractor/wit.rs

fce_wit_parser/extractor/
wit.rs
