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#include "node_wasm_web_api.h"
#include "memory_tracker-inl.h"
#include "node_errors.h"
namespace node {
namespace wasm_web_api {
using v8::ArrayBuffer;
using v8::ArrayBufferView;
using v8::Context;
using v8::Function;
using v8::FunctionCallbackInfo;
using v8::FunctionTemplate;
using v8::Local;
using v8::MaybeLocal;
using v8::Object;
using v8::Value;
using v8::WasmStreaming;
Local<Function> WasmStreamingObject::Initialize(Environment* env) {
Local<Function> templ = env->wasm_streaming_object_constructor();
if (!templ.IsEmpty()) {
return templ;
}
Local<FunctionTemplate> t = env->NewFunctionTemplate(New);
t->Inherit(BaseObject::GetConstructorTemplate(env));
t->InstanceTemplate()->SetInternalFieldCount(
WasmStreamingObject::kInternalFieldCount);
env->SetProtoMethod(t, "setURL", SetURL);
env->SetProtoMethod(t, "push", Push);
env->SetProtoMethod(t, "finish", Finish);
env->SetProtoMethod(t, "abort", Abort);
auto function = t->GetFunction(env->context()).ToLocalChecked();
env->set_wasm_streaming_object_constructor(function);
return function;
}
void WasmStreamingObject::RegisterExternalReferences(
ExternalReferenceRegistry* registry) {
registry->Register(New);
registry->Register(Push);
registry->Register(Finish);
registry->Register(Abort);
}
void WasmStreamingObject::MemoryInfo(MemoryTracker* tracker) const {
// v8::WasmStreaming is opaque. We assume that the size of the WebAssembly
// module that is being compiled is roughly what V8 allocates (as in, off by
// only a small factor).
tracker->TrackFieldWithSize("streaming", wasm_size_);
}
MaybeLocal<Object> WasmStreamingObject::Create(
Environment* env, std::shared_ptr<WasmStreaming> streaming) {
Local<Function> ctor = Initialize(env);
Local<Object> obj;
if (!ctor->NewInstance(env->context(), 0, nullptr).ToLocal(&obj)) {
return MaybeLocal<Object>();
}
CHECK(streaming);
WasmStreamingObject* ptr = Unwrap<WasmStreamingObject>(obj);
CHECK_NOT_NULL(ptr);
ptr->streaming_ = streaming;
ptr->wasm_size_ = 0;
return obj;
}
void WasmStreamingObject::New(const FunctionCallbackInfo<Value>& args) {
CHECK(args.IsConstructCall());
Environment* env = Environment::GetCurrent(args);
new WasmStreamingObject(env, args.This());
}
void WasmStreamingObject::SetURL(const FunctionCallbackInfo<Value>& args) {
WasmStreamingObject* obj;
ASSIGN_OR_RETURN_UNWRAP(&obj, args.Holder());
CHECK(obj->streaming_);
CHECK_EQ(args.Length(), 1);
CHECK(args[0]->IsString());
Utf8Value url(Environment::GetCurrent(args)->isolate(), args[0]);
obj->streaming_->SetUrl(url.out(), url.length());
}
void WasmStreamingObject::Push(const FunctionCallbackInfo<Value>& args) {
WasmStreamingObject* obj;
ASSIGN_OR_RETURN_UNWRAP(&obj, args.Holder());
CHECK(obj->streaming_);
CHECK_EQ(args.Length(), 1);
Local<Value> chunk = args[0];
// The start of the memory section backing the ArrayBuffer(View), the offset
// of the ArrayBuffer(View) within the memory section, and its size in bytes.
const void* bytes;
size_t offset;
size_t size;
if (LIKELY(chunk->IsArrayBufferView())) {
Local<ArrayBufferView> view = chunk.As<ArrayBufferView>();
bytes = view->Buffer()->GetBackingStore()->Data();
offset = view->ByteOffset();
size = view->ByteLength();
} else if (LIKELY(chunk->IsArrayBuffer())) {
Local<ArrayBuffer> buffer = chunk.As<ArrayBuffer>();
bytes = buffer->GetBackingStore()->Data();
offset = 0;
size = buffer->ByteLength();
} else {
return node::THROW_ERR_INVALID_ARG_TYPE(
Environment::GetCurrent(args),
"chunk must be an ArrayBufferView or an ArrayBuffer");
}
// Forward the data to V8. Internally, V8 will make a copy.
obj->streaming_->OnBytesReceived(static_cast<const uint8_t*>(bytes) + offset,
size);
obj->wasm_size_ += size;
}
void WasmStreamingObject::Finish(const FunctionCallbackInfo<Value>& args) {
WasmStreamingObject* obj;
ASSIGN_OR_RETURN_UNWRAP(&obj, args.Holder());
CHECK(obj->streaming_);
CHECK_EQ(args.Length(), 0);
obj->streaming_->Finish();
}
void WasmStreamingObject::Abort(const FunctionCallbackInfo<Value>& args) {
WasmStreamingObject* obj;
ASSIGN_OR_RETURN_UNWRAP(&obj, args.Holder());
CHECK(obj->streaming_);
CHECK_EQ(args.Length(), 1);
obj->streaming_->Abort(args[0]);
}
void StartStreamingCompilation(const FunctionCallbackInfo<Value>& info) {
// V8 passes an instance of v8::WasmStreaming to this callback, which we can
// use to pass the WebAssembly module bytes to V8 as we receive them.
// Unfortunately, our fetch() implementation is a JavaScript dependency, so it
// is difficult to implement the required logic here. Instead, we create a
// a WasmStreamingObject that encapsulates v8::WasmStreaming and that we can
// pass to the JavaScript implementation. The JavaScript implementation can
// then push() bytes from the Response and eventually either finish() or
// abort() the operation.
// Create the wrapper object.
std::shared_ptr<WasmStreaming> streaming =
WasmStreaming::Unpack(info.GetIsolate(), info.Data());
Environment* env = Environment::GetCurrent(info);
Local<Object> obj;
if (!WasmStreamingObject::Create(env, streaming).ToLocal(&obj)) {
// A JavaScript exception is pending. Let V8 deal with it.
return;
}
// V8 always passes one argument to this callback.
CHECK_EQ(info.Length(), 1);
// Prepare the JavaScript implementation for invocation. We will pass the
// WasmStreamingObject as the first argument, followed by the argument that we
// received from V8, i.e., the first argument passed to compileStreaming (or
// instantiateStreaming).
Local<Function> impl = env->wasm_streaming_compilation_impl();
CHECK(!impl.IsEmpty());
Local<Value> args[] = {obj, info[0]};
// Hand control to the JavaScript implementation. It should never throw an
// error, but if it does, we leave it to the calling V8 code to handle that
// gracefully. Otherwise, we assert that the JavaScript function does not
// return anything.
MaybeLocal<Value> maybe_ret =
impl->Call(env->context(), info.This(), 2, args);
Local<Value> ret;
CHECK_IMPLIES(maybe_ret.ToLocal(&ret), ret->IsUndefined());
}
// Called once by JavaScript during initialization.
void SetImplementation(const FunctionCallbackInfo<Value>& info) {
Environment* env = Environment::GetCurrent(info);
env->set_wasm_streaming_compilation_impl(info[0].As<Function>());
}
void Initialize(Local<Object> target,
Local<Value>,
Local<Context> context,
void*) {
Environment* env = Environment::GetCurrent(context);
env->SetMethod(target, "setImplementation", SetImplementation);
}
void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
registry->Register(SetImplementation);
registry->Register(StartStreamingCompilation);
WasmStreamingObject::RegisterExternalReferences(registry);
}
} // namespace wasm_web_api
} // namespace node
NODE_MODULE_CONTEXT_AWARE_INTERNAL(wasm_web_api, node::wasm_web_api::Initialize)
NODE_MODULE_EXTERNAL_REFERENCE(wasm_web_api,
node::wasm_web_api::RegisterExternalReferences)
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