Also note this other discussion: https://groups.google.com/g/v8-users/c/lRe7WrCkHCE/m/NmMfpDZ-DAAJ
On Fri, Feb 21, 2020 at 12:01 PM Darin Dimitrov <darin.dimit...@gmail.com> wrote: > 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 > <https://groups.google.com/d/msgid/v8-users/a1ad7cc0-e806-4a01-a88e-310dfe32613c%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- Clemens Backes Software Engineer cleme...@google.com Google Germany GmbH Erika-Mann-Straße 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg Diese E-Mail ist vertraulich. 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