#include "source/exe/process_wide.h"

#include "envoy/network/dns_resolver.h"

#include "source/common/common/assert.h"

#include "source/common/event/libevent.h"

#include "source/common/http/http2/nghttp2.h"

#include "source/server/proto_descriptors.h"

namespace Envoy {

namespace {

struct InitData {

  uint32_t count_ ABSL_GUARDED_BY(mutex_){};

  absl::Mutex mutex_;

};

// Static variable to count initialization pairs. For tests like

// main_common_test, we need to count to avoid double initialization or

// shutdown.

InitData& processWideInitData() { MUTABLE_CONSTRUCT_ON_FIRST_USE(InitData); };

} // namespace

ProcessWide::ProcessWide(bool validate_proto_descriptors) {

  // Note that the following lock has the dual use of making sure that initialization is complete

  // before a second caller can enter and leave this function.

  auto& init_data = processWideInitData();

  absl::MutexLock lock(&init_data.mutex_);

  if (init_data.count_++ == 0) {

    // TODO(mattklein123): Audit the following as not all of these have to be re-initialized in the

    // edge case where something does init/destroy/init/destroy.

    Event::Libevent::Global::initialize();

#if defined(ENVOY_ENABLE_FULL_PROTOS)

    if (validate_proto_descriptors) {

      Envoy::Server::validateProtoDescriptors();

    }

#else

    UNREFERENCED_PARAMETER(validate_proto_descriptors);

#endif

    Http::Http2::initializeNghttp2Logging();

    // We do not initialize Google gRPC here -- we instead instantiate

    // Grpc::GoogleGrpcContext in MainCommon immediately after instantiating

    // ProcessWide. This is because ProcessWide is instantiated in the unit-test

    // flow in test/test_runner.h, and grpc_init() instantiates threads which

    // allocate memory asynchronous to running tests, making it hard to

    // accurately measure memory consumption, and making unit-test debugging

    // non-deterministic. See https://github.com/envoyproxy/envoy/issues/8282

    // for details. Of course we also need grpc_init called in unit-tests that

    // test Google gRPC, and the relevant classes must also instantiate

    // Grpc::GoogleGrpcContext, which allows for nested instantiation.

    //

    // It appears that grpc_init() started instantiating threads in grpc 1.22.1,

    // which was integrated in https://github.com/envoyproxy/envoy/pull/8196,

    // around the time the flakes in #8282 started being reported.

  }

}

ProcessWide::~ProcessWide() {

  auto& init_data = processWideInitData();

  absl::MutexLock lock(&init_data.mutex_);

  ASSERT(init_data.count_ > 0);

  if (--init_data.count_ == 0) {

    Network::DnsResolverFactory::terminateFactories();

  }

}

} // namespace Envoy