I also encountered the same problem in v6.5 version, did you find the answer
在 2019年6月3日星期一 UTC+8下午11:29:36，Jian Guo写道：
>
> I tried to ship WebAssembly feature in v8 7.2 for my Android Project. I
> have successfully imported v8 as a static library. But I came across an
> issue that WebAssembly didn't call either then nor catch callback. Here
> is my code below:
>
> std::unique_ptr<v8::Platform> platform;
> v8::Isolate *isolate;
> v8::Persistent<v8::Context> persistentContext;
> void runMain();
> void runScript();
> void _log(const v8::FunctionCallbackInfo<v8::Value>& info) {
> v8::String::Utf8Value utf(isolate, info[0].As<v8::String>());
> __android_log_print(ANDROID_LOG_DEBUG, "V8Native", "%s",*utf);
> }
>
> void JNICALL
> Java_com_hustunique_v8demoapplication_MainActivity_initV8(JNIEnv *env,
> jobject /* this */) {
> // Initialize V8.
> v8::V8::InitializeICU();
> platform = v8::platform::NewDefaultPlatform();
> v8::V8::InitializePlatform(&(*platform.get()));
> v8::V8::Initialize();
> runMain();
> }
>
> void runMain() {
> // Create a new Isolate and make it the current one.
>
> v8::Isolate::CreateParams create_params;
> create_params.array_buffer_allocator =
> v8::ArrayBuffer::Allocator::NewDefaultAllocator();
> isolate = v8::Isolate::New(create_params);
> // isolate->Enter();
> v8::Isolate::Scope isolate_scope(isolate);
> v8::HandleScope scope(isolate);
>
>
> auto global_template = v8::ObjectTemplate::New(isolate);
> global_template->Set(v8::String::NewFromUtf8(isolate, "log"),
> v8::FunctionTemplate::New(isolate, _log)); // set log function here, as
> it is used in my sample javascript code
> // Enter the context for compiling and running the sample script.
> v8::Local<v8::Context> context = v8::Context::New(isolate, nullptr,
> global_template);
> persistentContext.Reset(isolate, context);
>
> // Run the script to get the result.
> runScript();
>
> }
>
> void runScript() {
> // sample wasm javascript code here.
> const char *csource = R"(
> WebAssembly.instantiate(new
> Uint8Array([0,97,115,109,1,0,0,0,1,8,2,96,1,127,0,96,0,0,2,8,1,2,106,
> 115,1,95,0,0,3,2,1,1,8,1,1,10,9,1,7,0,65,185,10,16,0,11]),
> {js:{_:console.log('Called from WebAssembly Hello
> world')}}).then(function(obj) {
> log('Called with instance ' + obj);
> }).catch(function(err) {
> log('Called with error ' + err);
> });
> )"; // should call my Hello World log and trigger the error or return
> the instance successfully
>
> v8::HandleScope handle_scope(isolate);
> auto ctx = persistentContext.Get(isolate);
> v8::Context::Scope context_scope(ctx);
> v8::TryCatch try_catch(isolate);
> v8::Local<v8::String> source = v8::String::NewFromUtf8(isolate, csource,
>
> v8::NewStringType::kNormal).ToLocalChecked();
>
> v8::Local<v8::Script> script =
> v8::Script::Compile(ctx, source).ToLocalChecked();
> v8::Local<v8::Value> result;
> if (!script->Run(ctx).ToLocal(&result)) {
> ReportException(isolate, &try_catch); // report exception, ignore the
> implementation here
> return;
> }
> // Convert the result to an UTF8 string and print it.
> v8::String::Utf8Value utf8(isolate, result);
> __android_log_print(ANDROID_LOG_INFO, "V8Native", "%s\n", *utf8);
>
> }
>
>
>
> In the demo above, I got the output with Called from WebAssembly Hello
> world as excepted, but I couldn't get the error message nor the instance
> info.
>
> I made a simple example on the website
> <https://webassembly.studio/?f=kwaxhg1bkbs> compared with my demo above,
> here is the output in the website, which can be reproduced easily I think:
>
>
> Called from WebAssembly Hello world
>>
>> Called with error LinkError: WebAssembly.instantiate(): Import #0
>> module="js" function="_" error: function import requires a callable
>>
>
>
> It seems that in my demo, neither resolve nor reject was called from
> WebAssembly's returning promise. After checking the type of
> v8::Local<v8::Value>
> result in runScript method, v8 runtime confirms that it is a promise
> object.
>
> I have tried several things here but none of them works:
>
> 1. 1. call v8::Isolate::RunMicroTasks(). Nothing happened
> 2. 2. cast result to v8::Local<v8::Promise> at the end of runScript
> method,
> then run with:
> 3.
> 4. auto resolver = v8::Resolver::New(context)->toLocalChecked();
> while (promise->State() == v8::PromiseState::kPending) {
> isolate->RunMicroTasks();
> }
> if (promise->State() == v8::PromiseState::kFullfilled) {
> resolver->Resolve(context, promise->Result());
> }
> if (promise->State() == v8::PromiseState::kRejected) {
> resolver->Reject(context, promise->Result());
> }
>
>
> This snippet didn't work either, besides, it stuck at the kPending status.
>
> I searched for something like flush the promise queue, but didn't get any
> solutions. What am I missing here?
>
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