_wat2wasm.py

from . import _ffi as ffi
from ctypes import *
from wasmtime import WasmtimeError
import typing


def wat2wasm(wat: typing.Union[str, bytes]) -> bytearray:
    """
    Converts the [WebAssembly Text format][wat] to the binary format.

    This function is intended to be a convenience function for local
    development and you likely don't want to use it extensively in production.
    It's much faster to parse and compile the binary format than it is to
    process the text format.

    Takes a `str` as input, raises an error if it fails to parse, and returns
    a `bytes` if conversion/parsing was successful.

    >>> wat2wasm('(module)')
    bytearray(b'\\x00asm\\x01\\x00\\x00\\x00')

    [wat]: https://webassembly.github.io/spec/core/text/index.html
    """

    if isinstance(wat, str):
        wat = wat.encode('utf8')
    wat_buffer = create_string_buffer(wat)
    wasm = ffi.wasm_byte_vec_t()
    error = ffi.wasmtime_wat2wasm(wat_buffer, len(wat), byref(wasm))
    if error:
        raise WasmtimeError._from_ptr(error)
    else:
        ret = ffi.to_bytes(wasm)
        ffi.wasm_byte_vec_delete(byref(wasm))
        return ret