bump rust-sdk version

crates/wit-parser/src/extractor.rs

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2020 Fluence Labs Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use super::custom::WIT_SECTION_NAME;
+use super::errors::WITParserError;
+
+use walrus::{IdsToIndices, ModuleConfig};
+use wasmer_wit::ast::Interfaces;
+use wasmer_core::Module as WasmerModule;
+
+use std::path::PathBuf;
+
+/// Extracts WIT section of provided Wasm binary and converts it to a string.
+pub fn extract_text_wit(wasm_file_path: PathBuf) -> Result<String, WITParserError> {
+    let wit_section_bytes = extract_wit_section_bytes(wasm_file_path)?;
+    let wit = extract_wit_with_fn(&wit_section_bytes)?;
+    Ok((&wit).to_string())
+}
+
+/// Extracts WIT section of provided Wasm binary and converts it to a FCEWITInterfaces.
+pub fn extract_wit(wasmer_module: &WasmerModule) -> Result<Interfaces<'_>, WITParserError> {
+    let wit_sections = wasmer_module
+        .custom_sections(WIT_SECTION_NAME)
+        .ok_or_else(|| WITParserError::NoWITSection)?;
+
+    if wit_sections.len() > 1 {
+        return Err(WITParserError::MultipleWITSections);
+    }
+
+    extract_wit_with_fn(&wit_sections[0])
+}
+
+fn extract_wit_with_fn(wit_section_bytes: &[u8]) -> Result<Interfaces<'_>, WITParserError> {
+    match wasmer_wit::decoders::binary::parse::<()>(&wit_section_bytes) {
+        Ok((remainder, wit)) if remainder.is_empty() => Ok(wit),
+        Ok(_) => Err(WITParserError::WITRemainderNotEmpty),
+        Err(_) => Err(WITParserError::CorruptedWITSection),
+    }
+}
+
+fn extract_wit_section_bytes(wasm_file_path: PathBuf) -> Result<Vec<u8>, WITParserError> {
+    let module = ModuleConfig::new()
+        .parse_file(wasm_file_path)
+        .map_err(WITParserError::CorruptedWasmFile)?;
+
+    let sections = module
+        .customs
+        .iter()
+        .filter(|(_, section)| section.name() == WIT_SECTION_NAME)
+        .collect::<Vec<_>>();
+
+    if sections.is_empty() {
+        return Err(WITParserError::NoWITSection);
+    }
+    if sections.len() > 1 {
+        return Err(WITParserError::MultipleWITSections);
+    }
+
+    let default_ids = IdsToIndices::default();
+    Ok(sections[0].1.data(&default_ids).into_owned())
+}