Files
wasmtime/crates/misc/dotnet/src/Engine.cs
Alex Crichton 77e17d8f71 Add a wasmtime-specific wasmtime_wat2wasm C API (#1206)
* Add a wasmtime-specific `wasmtime_wat2wasm` C API

This commit implements a wasmtime-specific C API for converting the text
format to the binary format. An upstream spec issue exists for adding
this to the C API, but in the meantime we can experiment with our own
version of this API and use it in the C# extension, for example!

Closes #1000

* Reorder arguments

* Use wasm_byte_vec_t for input `*.wat`

* Mark wat input as const

* Return an error message and use `fixed`

* Actually include the error message

* Use `fixed` in `Module.cs` as well
2020-03-03 10:29:20 -06:00

86 lines
2.8 KiB
C#

using System;
using System.Text;
using System.Runtime.InteropServices;
namespace Wasmtime
{
/// <summary>
/// Represents the Wasmtime engine.
/// </summary>
public class Engine : IDisposable
{
/// <summary>
/// Constructs a new <see cref="Engine" />.
/// </summary>
public Engine()
{
Handle = Interop.wasm_engine_new();
if (Handle.IsInvalid)
{
throw new WasmtimeException("Failed to create Wasmtime engine.");
}
}
internal Engine(Interop.WasmConfigHandle config)
{
Handle = Interop.wasm_engine_new_with_config(config);
config.SetHandleAsInvalid();
if (Handle.IsInvalid)
{
throw new WasmtimeException("Failed to create Wasmtime engine.");
}
}
/// <summary>
/// Creates a new Wasmtime <see cref="Store" />.
/// </summary>
/// <returns>Returns the new <see cref="Store" />.</returns>
public Store CreateStore()
{
return new Store(this);
}
/// <summary>
/// Converts the WebAssembly text format to the binary format
/// </summary>
/// <returns>Returns the binary-encoded wasm module.</returns>
public byte[] WatToWasm(string wat)
{
var watBytes = Encoding.UTF8.GetBytes(wat);
unsafe
{
fixed (byte *ptr = watBytes)
{
Interop.wasm_byte_vec_t watByteVec;
watByteVec.size = (UIntPtr)watBytes.Length;
watByteVec.data = ptr;
if (!Interop.wasmtime_wat2wasm(Handle, ref watByteVec, out var bytes, out var error)) {
var errorSpan = new ReadOnlySpan<byte>(error.data, checked((int)error.size));
var message = Encoding.UTF8.GetString(errorSpan);
Interop.wasm_byte_vec_delete(ref error);
throw new WasmtimeException("failed to parse input wat: " + message);
}
var byteSpan = new ReadOnlySpan<byte>(bytes.data, checked((int)bytes.size));
var ret = byteSpan.ToArray();
Interop.wasm_byte_vec_delete(ref bytes);
return ret;
}
}
}
/// <inheritdoc/>
public void Dispose()
{
if (!Handle.IsInvalid)
{
Handle.Dispose();
Handle.SetHandleAsInvalid();
}
}
internal Interop.EngineHandle Handle { get; private set; }
}
}