wasi: add stub for sock-accept

Refs: nodejs/uvwasi#185

Add stub for sock-accept so that we have stubs for all snapshot 1
methods. Since they changed the spec late in the same it is
awkward but I think it is semver minor at most to add the missing
stub.

Depends on the uvwasi nodejs/uvwasi#185
to land first and to have an updated uvwasi version pulled into
Node.js.

Signed-off-by: Michael Dawson <mdawson@devrus.com>

src/node_wasi.cc

@@ -1234,6 +1234,38 @@ uint32_t WASI::SockShutdown(WASI& wasi,
   return uvwasi_sock_shutdown(&wasi.uvw_, sock, how);
 }
 
+void WASI::SockAccept(const FunctionCallbackInfo<Value>& args) {
+  WASI* wasi;
+  uint32_t sock;
+  uint32_t flags;
+  uint32_t fd_ptr;
+  char* memory;
+  size_t mem_size;
+  RETURN_IF_BAD_ARG_COUNT(args, 3);
+  CHECK_TO_TYPE_OR_RETURN(args, args[0], Uint32, sock);
+  CHECK_TO_TYPE_OR_RETURN(args, args[1], Uint32, flags);
+  CHECK_TO_TYPE_OR_RETURN(args, args[2], Uint32, fd_ptr);
+  ASSIGN_INITIALIZED_OR_RETURN_UNWRAP(&wasi, args.This());
+  Debug(wasi,
+        "sock_accept(%d, %d, %d)\n",
+        sock,
+        flags,
+        fd_ptr);
+  GET_BACKING_STORE_OR_RETURN(wasi, args, &memory, &mem_size);
+  CHECK_BOUNDS_OR_RETURN(args, mem_size, fd_ptr, UVWASI_SERDES_SIZE_fd_t);
+
+  uvwasi_fd_t fd;
+  uvwasi_errno_t err =  uvwasi_sock_accept(&wasi->uvw_,
+                                           sock,
+                                           flags,
+                                           &fd);
+
+  if (err == UVWASI_ESUCCESS)
+    uvwasi_serdes_write_size_t(memory, fd_ptr, fd);
+
+  args.GetReturnValue().Set(err);
+}
+
 void WASI::_SetMemory(const FunctionCallbackInfo<Value>& args) {
   WASI* wasi;
   ASSIGN_OR_RETURN_UNWRAP(&wasi, args.This());

src/node_wasi.h

@@ -142,6 +142,7 @@ class WASI : public BaseObject,
   static uint32_t SockSend(
       WASI&, WasmMemory, uint32_t, uint32_t, uint32_t, uint32_t, uint32_t);
   static uint32_t SockShutdown(WASI&, WasmMemory, uint32_t, uint32_t);
+  static void SockAccept(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   static void _SetMemory(const v8::FunctionCallbackInfo<v8::Value>& args);