// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "test/wasm-api-tests/wasm-api-test.h"

#include <mutex>
#include <thread>

namespace v8 {
namespace internal {
namespace wasm {

using ::wasm::Shared;

namespace {

const int kNumThreads = 10;
const int kIterationsPerThread = 3;
int g_traces;

own<Trap*> Callback(void* env, const Val args[], Val results[]) {
  std::lock_guard<std::mutex> lock(*reinterpret_cast<std::mutex*>(env));
  g_traces += args[0].i32();
  return nullptr;
}

void Main(Engine* engine, Shared<Module>* shared, std::mutex* mutex, int id) {
  own<Store*> store = Store::make(engine);
  own<Module*> module = Module::obtain(store.get(), shared);
  EXPECT_NE(nullptr, module.get());
  for (int i = 0; i < kIterationsPerThread; i++) {
    std::this_thread::sleep_for(std::chrono::microseconds(100));

    // Create imports.
    own<FuncType*> func_type = FuncType::make(
        vec<ValType*>::make(ValType::make(::wasm::I32)), vec<ValType*>::make());
    own<Func*> func = Func::make(store.get(), func_type.get(), Callback, mutex);
    own<::wasm::GlobalType*> global_type =
        ::wasm::GlobalType::make(ValType::make(::wasm::I32), ::wasm::CONST);
    own<Global*> global =
        Global::make(store.get(), global_type.get(), Val::i32(id));

    // Instantiate and run.
    // With the current implementation of the WasmModuleBuilder, global
    // imports always come before function imports, regardless of the
    // order of builder()->Add*Import() calls below.
    Extern* imports[] = {global.get(), func.get()};
    own<Instance*> instance =
        Instance::make(store.get(), module.get(), imports);
    vec<Extern*> exports = instance->exports();
    Func* run_func = exports[0]->func();
    run_func->call();
  }
}

}  // namespace

TEST_F(WasmCapiTest, Threads) {
  // Create module.
  ValueType i32_type[] = {kWasmI32};
  FunctionSig param_i32(0, 1, i32_type);
  uint32_t callback_index =
      builder()->AddImport(CStrVector("callback"), &param_i32);
  uint32_t global_index =
      builder()->AddGlobalImport(CStrVector("id"), kWasmI32, false);

  byte code[] = {
      WASM_CALL_FUNCTION(callback_index, WASM_GET_GLOBAL(global_index))};
  FunctionSig empty_sig(0, 0, nullptr);
  AddExportedFunction(CStrVector("run"), code, sizeof(code), &empty_sig);
  Compile();
  own<Shared<Module>*> shared = module()->share();

  // Spawn threads.
  g_traces = 0;
  std::mutex mutex;
  std::thread threads[kNumThreads];
  for (int i = 0; i < kNumThreads; i++) {
    threads[i] = std::thread(Main, engine(), shared.get(), &mutex, i);
  }
  for (int i = 0; i < kNumThreads; i++) {
    threads[i].join();
  }
  // Each thread in each iteration adds its ID to {traces}, so in the end
  // we expect kIterationsPerThread * sum([0, ..., kNumThreads-1]).
  // Per Gauss:
  const int kExpected =
      kIterationsPerThread * (kNumThreads - 1) * kNumThreads / 2;
  EXPECT_EQ(kExpected, g_traces);
}

TEST_F(WasmCapiTest, MultiStoresOneThread) {
  // These Stores intentionally have overlapping, but non-nested lifetimes.
  own<Store*> store1 = Store::make(engine());
  own<Store*> store2 = Store::make(engine());
  own<Store*> store3 = Store::make(engine());
  store1.reset();
  store2.reset();
  store3.reset();
}

}  // namespace wasm
}  // namespace internal
}  // namespace v8