public WasmLoader()

in dubbo-wasm/dubbo-wasm-api/src/main/java/org/apache/dubbo/wasm/WasmLoader.java [93:146]
48 lines of code
17 McCabe index (conditional complexity)

    public WasmLoader(final Class<?> wasmClass,
                      final Function<Class<?>, String> nameInitializer,
                      final BiFunction<Store<Void>, Supplier<ByteBuffer>, Map<String, Func>> initializer) {
        final Class<?> clazz = Objects.nonNull(wasmClass) ? wasmClass : this.getClass();
        String wasmName = null;
        try {
            if (Objects.nonNull(nameInitializer)) {
                wasmName = nameInitializer.apply(clazz);
            }
            if (Objects.isNull(wasmName) || wasmName.isEmpty()) {
                wasmName = buildWasmName(clazz);
            }
            if (Objects.isNull(wasmName) || wasmName.isEmpty()) {
                throw new DubboWasmInitException("Illegal WASM file name");
            }
            this.wasmName = wasmName.endsWith(".wasm") ? wasmName : wasmName + ".wasm";
            // locate `.wasm` lib.
            URL resource = clazz.getClassLoader().getResource(wasmName);
            if (Objects.isNull(resource)) {
                throw new DubboWasmInitException("Can't find wasm file: " + wasmName);
            }
            // Reads the WebAssembly module as bytes.
            byte[] wasmBytes = Files.readAllBytes(Paths.get(resource.toURI()));
            // Instantiates the WebAssembly module.
            if (Objects.nonNull(initializer)) {
                Map<String, Func> wasmFunctionMap = initializer.apply(store, this::getBuffer);
                if (Objects.nonNull(wasmFunctionMap) && !wasmFunctionMap.isEmpty()) {
                    wasmCallJavaFuncMap.putAll(wasmFunctionMap);
                }
            }
            Map<String, Func> wasmFunctionMap = initWasmCallJavaFunc(store, this::getBuffer);
            if (Objects.nonNull(wasmFunctionMap) && !wasmFunctionMap.isEmpty()) {
                wasmCallJavaFuncMap.putAll(wasmFunctionMap);
            }
            this.module = Module.fromBinary(store.engine(), wasmBytes);
            WasiCtx.addToLinker(linker);
            // maybe need define many functions
            if (!wasmCallJavaFuncMap.isEmpty()) {
                wasmCallJavaFuncMap.forEach((funcName, wasmCallJavaFunc) ->
                    linker.define(store, IMPORT_WASM_MODULE_NAME, funcName, Extern.fromFunc(wasmCallJavaFunc)));
            }
            linker.module(store, "", module);
            // Let the `wasmCallJavaFunc` function to refer this as a placeholder of Memory because
            // we have to add the function as import before loading the module exporting Memory.
            Optional<Extern> extern = this.getWasmExtern(MEMORY_METHOD_NAME);
            if (!extern.isPresent()) {
                throw new DubboWasmInitException(MEMORY_METHOD_NAME + " function not find in wasm file: " + wasmName);
            }
            this.memRef.set(extern.get().memory());
            Runtime.getRuntime().addShutdownHook(new Thread(this::close));
        } catch (URISyntaxException | IOException e) {
            throw new DubboWasmInitException(e);
        }
    }