0.3.0

Notable Changes

This release features support for elixir function that can be exported to WASM.

It also supports the latest wasmer v 1.0 🎉.
Wasmer 1.0 is a partial rewrite of the WASM engine we use that promises to be up to 9 times faster module compilation.

Added

• added the instances first memory into the callback context

imports = %{
  env: %{
    read_and_set_memory:
      {:fn, [], [:i32],
        fn context, a, b, c ->
          memory = Map.get(context, :memory)
          42 = Wasmex.Memory.get(memory, :uint8, 0, 0) # assert that the first byte in the memory was set to 42
          Wasmex.Memory.set(memory, :uint8, 0, 0, 23)
          0
        end},
  }
}

instance = start_supervised!({Wasmex, %{bytes: @import_test_bytes, imports: imports}})
Wasmex.Memory.set(memory, :uint8, 0, 0, 42)

# asserts that the byte at memory[0] was set to 42 and then sets it to 23
{:ok, _} = Wasmex.call_function(instance, :a_wasm_fn_that_calls_read_and_set_memory, [])

assert 23 == Wasmex.Memory.get(memory, :uint8, 0, 0)

• added support for function imports

imports = %{
  env: %{
    sum3: {:fn, [:i32, :i32, :i32], [:i32], fn (_context, a, b, c) -> a + b + c end},
  }
}
instance = start_supervised!({Wasmex, %{bytes: @import_test_bytes, imports: imports}})

{:ok, [6]} = Wasmex.call_function(instance, "use_the_imported_sum_fn", [1, 2, 3])

Thanks to

• @bamorim for helping me plan and architect,
• @myobie for help in implementation, especially for implementing the function signature checks,
• @rylev for a second eye on our Rust code,
• the @wasmerio team for the recent addition of DynFunc which made this feature possible, and
• @bitcrowd for sponsoring me to work on this feature

Changed

• Changed writing and reading strings from/to memory to be based on string length and not expect null-byte terminated strings.
  This allows for a more flexible memory handling when writing arbitrary data or strings containing null bytes to/from memory.
  Thanks @myobie for implementing this feature
• Support writing non-string binaries to memory. Before we could only write valid UTF-8 strings to WASM memory.
  Thanks again, @myobie, for implementing this feature
• Updated the wasmer version, now supporting wasmer 1.0.
• Updated to elixir 1.11 and Erlang OTP 23.2. Older versions might work, but are not officially tested

Fixed

• could not convert callback result param to expected return signature error for a void callback.