I solved this problem. The reason is I decleared
`std::unique_ptr<v8::Platform>` as local variable then its destructor will
be invoked at last of the `Initialize` method.
I changed to store the value on the `Core` class side then the problem was
solved.
2022年5月5日木曜日 21:41:57 UTC+9 Kazuya Hiruma:
> I'm new to C++ and V8.
>
> I'm googling some scripts for creating a V8 engine wrapper.
>
> I refered some implementations to implement my system. I'm so confused why
> the error is occurred.
>
> My all code are below.
>
> *1. Header*
>
> #pragma once
> #include <v8.h>
>
> namespace v8_api
> {
> class Core
> {
> private:
> v8::Isolate* isolate_;
> v8::Global<v8::Context> impl_;
>
> public:
> void Initialize();
> void Run(const char* source_code);
> };
> }
>
>
> *2. Implementation*
>
> #include <iostream>
> #include "include/v8.h"
> #include "include/libplatform/libplatform.h"
> #include "v8api.h"
>
> namespace v8_api
> {
> void Core::Initialize()
> {
> std::cout << "Initializing v8_api::Core\n";
>
> v8::V8::InitializeICU();
>
> std::unique_ptr<v8::Platform> platform =
> v8::platform::NewDefaultPlatform();
> v8::V8::InitializePlatform(platform.get());
> v8::V8::Initialize();
>
> v8::Isolate::CreateParams create_params;
> create_params.array_buffer_allocator =
> v8::ArrayBuffer::Allocator::NewDefaultAllocator();
> isolate_ = v8::Isolate::New(create_params);
>
> v8::Isolate::Scope isolate_scope(isolate_);
> v8::HandleScope scope(isolate_);
> v8::Local<v8::Context> impl = v8::Context::New(isolate_);
> impl_.Reset(isolate_, impl);
> }
>
> void Core::Run(const char* source_code)
> {
> v8::HandleScope handle_scope(isolate_);
> {
> v8::Local<v8::Context> context = v8::Context::New(isolate_);
> v8::Context::Scope context_scope(context);
> {
> v8::MaybeLocal<v8::String> m_source =
> v8::String::NewFromUtf8(isolate_, source_code);
> v8::Local<v8::String> source = m_source.ToLocalChecked();
> v8::MaybeLocal<v8::Script> m_script =
> v8::Script::Compile(context, source);
> v8::Local<v8::Script> script;
> if (!v8::Script::Compile(context, source).ToLocal(&script))
> {
> return;
> }
> v8::Local<v8::Value> result =
> script->Run(isolate_->GetCurrentContext()).ToLocalChecked();
> v8::String::Utf8Value resultStr(isolate_, result);
> std::cout << *resultStr;
> }
> }
> }
> }
>
>
> *3. A code that runs the system.*
>
> #include <iostream>
> #include <thread>
> #include "v8.h"
> #include "v8api.h"
>
> int main(int argc, char* argv[])
> {
> std::cout << "Hello World!\n";
>
> v8_api::Core* core = new v8_api::Core();
> core->Initialize();
>
> const char* src = "var a = 4;";
> core->Run(src);
>
> std::this_thread::sleep_for(std::chrono::milliseconds(1000));
>
> return 0;
> }
>
>
> What my question is that why compiling will fail.
>
> The steps are below. (This is done by third code)
>
> 1. Create an instance of "Core".
> 2. Initialize the Core.
> 3. Invoke its method "Run" with a JavaScript code.
> 4. It happens the error "Access violation executing location" !
>
> What the error is below.
> [image: error-screenshot.png]
>
> I noticed that "m_script" is NULL but I'm not sure why it returns NULL.
> The JavaScript code is so simple and correct I think.
>
> --------------------------------
>
> Additional Info:
> If I run a JavaScript code in the "Initialize" method like below. After
> that, all executing "Run" method work fine with no error.
>
> v8::Isolate::Scope isolate_scope(isolate_);
> v8::HandleScope scope(isolate_);
> v8::Local<v8::Context> impl = v8::Context::New(isolate_);
> impl_.Reset(isolate_, impl);
>
> const char* src = "var a = 30.5;";
> Run(src);
>
> After that, the code below will work fine. (This is in third code)
>
> const char* src = "var a = 4;";
> core->Run(src);
>
> I'm sooo confused. Is there any my mistake?
>
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