I had the same problem in my Android project and used a workaround. I replaced the global.WebAssembly object with a Proxy and intercept the "compile" and "instantiate" method calls. When this method is called I start a new background thread which is polling the main looper to pump messages and run the pending microtasks. When the promise is resolved the background thread is destroyed.
Here's the implementation I used: https://github.com/NativeScript/android-runtime/blob/d11015b62df914535947957b4a29ebf9085564e7/test-app/runtime/src/main/cpp/MessageLoopTimer.cpp On Tuesday, December 31, 2019 at 11:19:11 AM UTC+2, aimaomao wo wrote: > > 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? >> > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/v8-users/a1ad7cc0-e806-4a01-a88e-310dfe32613c%40googlegroups.com.
