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very simple first cut of ESM and top level await
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@billywhizz
billywhizz committed Aug 11, 2022
1 parent 01377b5 commit ee760a1
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Showing 3 changed files with 136 additions and 19 deletions.
131 changes: 115 additions & 16 deletions just.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -119,11 +119,6 @@ void just::PrintStackTrace(Isolate* isolate, const TryCatch& try_catch) {
fflush(stderr);
}

v8::MaybeLocal<v8::Module> just::OnModuleInstantiate(Local<Context> context,
Local<String> specifier, Local<Module> referrer) {
return MaybeLocal<Module>();
}

void just::PromiseRejectCallback(PromiseRejectMessage data) {
if (data.GetEvent() == v8::kPromiseRejectAfterResolved ||
data.GetEvent() == v8::kPromiseResolveAfterResolved) {
Expand Down Expand Up @@ -174,6 +169,103 @@ void just::FreeMemory(void* buf, size_t length, void* data) {
free(buf);
}

char* readFile(char filename[]) {
std::ifstream file;
file.open(filename, std::ifstream::ate);
char* contents;
if (!file) {
contents = new char[1];
return contents;
}
size_t file_size = file.tellg();
file.seekg(0);
std::filebuf* file_buf = file.rdbuf();
contents = new char[file_size + 1]();
file_buf->sgetn(contents, file_size);
file.close();
return contents;
}

v8::MaybeLocal<v8::Module> loadModule(char code[],
char name[],
v8::Local<v8::Context> cx) {
v8::Local<v8::String> vcode =
v8::String::NewFromUtf8(cx->GetIsolate(), code).ToLocalChecked();
v8::Local<v8::PrimitiveArray> opts =
v8::PrimitiveArray::New(cx->GetIsolate(), just::HostDefinedOptions::kLength);
opts->Set(cx->GetIsolate(), just::HostDefinedOptions::kType,
v8::Number::New(cx->GetIsolate(), just::ScriptType::kModule));
v8::ScriptOrigin origin(cx->GetIsolate(), v8::String::NewFromUtf8(cx->GetIsolate(), name).ToLocalChecked(), // resource name
0, // line offset
0, // column offset
true, // is shared cross-origin
-1, // script id
v8::Local<v8::Value>(), // source map url
false, // is opaque
false, // is wasm
true, // is module
opts);
v8::Context::Scope context_scope(cx);
v8::ScriptCompiler::Source source(vcode, origin);
v8::MaybeLocal<v8::Module> mod;
mod = v8::ScriptCompiler::CompileModule(cx->GetIsolate(), &source);
return mod;
}

// lifted from here: https://gist.github.com/surusek/4c05e4dcac6b82d18a1a28e6742fc23e
v8::MaybeLocal<v8::Module> just::OnModuleInstantiate(v8::Local<v8::Context> context,
v8::Local<v8::String> specifier,
v8::Local<v8::FixedArray> import_assertions,
v8::Local<v8::Module> referrer) {
v8::String::Utf8Value str(context->GetIsolate(), specifier);
return loadModule(readFile(*str), *str, context);
}

v8::Local<v8::Module> checkModule(v8::MaybeLocal<v8::Module> maybeModule,
v8::Local<v8::Context> cx) {
v8::Local<v8::Module> mod;
if (!maybeModule.ToLocal(&mod)) {
printf("Error loading module!\n");
exit(EXIT_FAILURE);
}
v8::Maybe<bool> result = mod->InstantiateModule(cx, just::OnModuleInstantiate);
if (result.IsNothing()) {
printf("\nCan't instantiate module.\n");
exit(EXIT_FAILURE);
}
return mod;
}

v8::Local<v8::Value> execModule(v8::Local<v8::Module> mod,
v8::Local<v8::Context> cx,
bool nsObject) {
v8::Local<v8::Value> retValue;
if (!mod->Evaluate(cx).ToLocal(&retValue)) {
printf("Error evaluating module!\n");
exit(EXIT_FAILURE);
}
if (nsObject)
return mod->GetModuleNamespace();
else
return retValue;
}

v8::MaybeLocal<v8::Promise> OnDynamicImport(v8::Local<v8::Context> context,
v8::Local<v8::ScriptOrModule> referrer,
v8::Local<v8::String> specifier,
v8::Local<v8::FixedArray> import_assertions) {
fprintf(stderr, "OnDynamicImport\n");
v8::Local<v8::Promise::Resolver> resolver =
v8::Promise::Resolver::New(context).ToLocalChecked();
v8::MaybeLocal<v8::Promise> promise(resolver->GetPromise());
v8::String::Utf8Value name(context->GetIsolate(), specifier);
v8::Local<v8::Module> mod =
checkModule(loadModule(readFile(*name), *name, context), context);
v8::Local<v8::Value> retValue = execModule(mod, context, true);
resolver->Resolve(context, retValue).ToChecked();
return promise;
}

int just::CreateIsolate(int argc, char** argv,
const char* main_src, unsigned int main_len,
const char* js, unsigned int js_len, struct iovec* buf, int fd,
Expand All @@ -197,6 +289,7 @@ int just::CreateIsolate(int argc, char** argv,
Local<Context> context = Context::New(isolate, NULL, global);
Context::Scope context_scope(context);
isolate->SetPromiseRejectCallback(PromiseRejectCallback);
isolate->SetHostImportModuleDynamicallyCallback(OnDynamicImport);
Local<Array> arguments = Array::New(isolate);
for (int i = 0; i < argc; i++) {
arguments->Set(context, i, String::NewFromUtf8(isolate, argv[i],
Expand Down Expand Up @@ -239,8 +332,9 @@ int just::CreateIsolate(int argc, char** argv,
TryCatch try_catch(isolate);

Local<v8::PrimitiveArray> opts =
v8::PrimitiveArray::New(isolate, 1);
opts->Set(isolate, 0, v8::Number::New(isolate, 1));
v8::PrimitiveArray::New(isolate, just::HostDefinedOptions::kLength);
opts->Set(isolate, just::HostDefinedOptions::kType,
v8::Number::New(isolate, just::ScriptType::kModule));
ScriptOrigin baseorigin(
isolate,
String::NewFromUtf8Literal(isolate, "just.js",
Expand All @@ -252,25 +346,30 @@ int just::CreateIsolate(int argc, char** argv,
Local<Value>(), // source map url
false, // is opaque
false, // is wasm
false, // is module
true, // is module
opts
);
Local<Script> script;
Local<String> base;
base = String::NewFromUtf8(isolate, main_src, NewStringType::kNormal,
main_len).ToLocalChecked();
ScriptCompiler::Source basescript(base, baseorigin);
if (!ScriptCompiler::Compile(context, &basescript).ToLocal(&script)) {
Local<Module> module;
if (!ScriptCompiler::CompileModule(isolate, &basescript).ToLocal(&module)) {
PrintStackTrace(isolate, try_catch);
return 1;
}
MaybeLocal<Value> maybe_result = script->Run(context);
Local<Value> result;
if (!maybe_result.ToLocal(&result)) {
just::PrintStackTrace(isolate, try_catch);
return 2;
Maybe<bool> ok2 = module->InstantiateModule(context, just::OnModuleInstantiate);
if (ok2.IsNothing()) {
if (try_catch.HasCaught() && !try_catch.HasTerminated()) {
try_catch.ReThrow();
}
return 1;
}
module->Evaluate(context).ToLocalChecked();
if (try_catch.HasCaught() && !try_catch.HasTerminated()) {
try_catch.ReThrow();
return 1;
}

Local<Value> func = globalInstance->Get(context,
String::NewFromUtf8Literal(isolate, "onExit",
NewStringType::kNormal)).ToLocalChecked();
Expand Down
18 changes: 16 additions & 2 deletions just.h
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,19 @@ using v8::Promise;
using v8::PromiseRejectEvent;
using v8::Uint32Array;
using v8::BigUint64Array;
using v8::FixedArray;

enum ScriptType : int {
kScript,
kModule,
kFunction,
};

enum HostDefinedOptions : int {
kType = 8,
kID = 9,
kLength = 10,
};

ssize_t process_memory_usage();

Expand All @@ -73,8 +86,9 @@ void builtins_add (const char* name, const char* source,

using InitializerCallback = void (*)(Isolate* isolate,
Local<ObjectTemplate> exports);
MaybeLocal<Module> OnModuleInstantiate(Local<Context> context,
Local<String> specifier, Local<Module> referrer);
v8::MaybeLocal<v8::Module> OnModuleInstantiate(v8::Local<v8::Context> context,
v8::Local<v8::String> specifier, v8::Local<v8::FixedArray> import_assertions,
v8::Local<v8::Module> referrer);

int CreateIsolate(int argc, char** argv,
const char* main, unsigned int main_len,
Expand Down
6 changes: 5 additions & 1 deletion just.js
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Original file line number Diff line number Diff line change
Expand Up @@ -362,7 +362,11 @@
}
const scriptName = just.path.join(just.sys.cwd(), just.args[1])
just.main = just.fs.readFile(just.args[1])
just.vm.runScript(just.main, scriptName)
if (opts.esm) {
just.vm.runModule(just.main, scriptName)
} else {
just.vm.runScript(just.main, scriptName)
}
}
if (opts.inspector) {
const inspectorLib = just.library('inspector')
Expand Down

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