#include <jni.h>

#include <string>

#include "libplatform/libplatform.h"

#include "v8.h"

/* the following references need to be around somewhere,

* either as global (not recommended), or in some object,

* otherwise they'll get garbage collected by C++

* and cause a segmentation fault crash

*/

std::unique_ptr<v8::Platform> platform;

v8::Isolate *isolate;

v8::Persistent<v8::Context> persistentContext;

extern "C" JNIEXPORT void

JNICALL

Java_org_cmdr2_jnitest_MyActivity_initV8(

JNIEnv *env,

jobject /* this */) {

// Initialize V8.

v8::V8::InitializeICU();

platform = v8::platform::NewDefaultPlatform();

v8::V8::InitializePlatform(&(*platform.get()));

v8::V8::Initialize();

// 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);

v8::Isolate::Scope isolate_scope(isolate);

// Create a stack-allocated handle scope.

v8::HandleScope handle_scope(isolate);

// Create a new context.

v8::Local<v8::Context> context = v8::Context::New(isolate);

// attach the context to the persistent context, to avoid V8 GC-ing it

persistentContext.Reset(isolate, context);

}

extern "C" JNIEXPORT jstring

JNICALL

Java_org_cmdr2_jnitest_MyActivity_stringFromV8(

JNIEnv *env,

jobject /* this */) {

std::string hello = "Hello v8 from C++!\n";

v8::Isolate::Scope isolate_scope(isolate);

v8::HandleScope handle_scope(isolate);

// Enter the context for compiling and running the hello world script.

v8::Local<v8::Context> context = v8::Local<v8::Context>::New(isolate, persistentContext);

v8::Context::Scope context_scope(context);

// Create a string containing the JavaScript source code.

v8::Local<v8::String> source = v8::String::NewFromUtf8(

isolate, "'Hello' + ', from Javascript!'", v8::NewStringType::kNormal).ToLocalChecked();

// Compile the source code.

v8::Local<v8::Script> script =

v8::Script::Compile(context, source).ToLocalChecked();

// Run the script to get the result.

v8::Local<v8::Value> result = script->Run(context).ToLocalChecked();

// Convert the result to an UTF8 string and print it.

v8::String::Utf8Value utf8(isolate, result);

printf("%s\n", *utf8);

hello += *utf8;

return env->NewStringUTF(hello.c_str());

}