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//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "server/mozc_server.h"

#ifdef OS_WIN
#include <windows.h>
#endif

#include <cstddef>
#include <string>

#include "base/crash_report_handler.h"
#include "base/init.h"
#include "base/logging.h"
#include "base/process_mutex.h"
#include "base/run_level.h"
#include "base/system_util.h"
#include "config/stats_config_util.h"
#include "session/session_server.h"

DECLARE_bool(restricted);   // in SessionHandler

namespace {
mozc::SessionServer *g_session_server = NULL;
}

namespace mozc {
namespace {

// Calling back a function when the mozc server is shutting down resulted in a
// lot of crashes as filed in b/2696087.
// TODO(yukawa): re-enable shutdown handler for Windows.
#if !defined(OS_WIN)
// When OS is about to shutdown/logoff,
// ShutdownSessionCallback is kicked.
void ShutdownSessionCallback() {
  VLOG(1) << "ShutdownSessionFunc is called";
  if (g_session_server != NULL) {
    g_session_server->Terminate();
  }
}

REGISTER_MODULE_SHUTDOWN_HANDLER(shutdown_session,
                                 ShutdownSessionCallback());
#endif  // !OS_WIN
}  // namespace

namespace server {

void InitGoogleAndMozcServer(const char *arg0,
                             int *argc,
                             char ***argv,
                             bool remove_flags) {
  mozc::SystemUtil::DisableIME();

  // Big endian is not supported. The storage for user history is endian
  // dependent. If we want to sync the data via network sync feature, we
  // will see some problems.
  CHECK(mozc::SystemUtil::IsLittleEndian()) << "Big endian is not supported.";
#ifdef OS_WIN
  // http://msdn.microsoft.com/en-us/library/ms686227.aspx
  // Make sure that mozc_server exits all after other processes.
  ::SetProcessShutdownParameters(0x100, SHUTDOWN_NORETRY);
#endif

  // call GetRunLevel before InitGoogle().
  // InitGoogle() will do all static initialization and may access
  // local resources.
  const mozc::RunLevel::RunLevelType run_level =
      mozc::RunLevel::GetRunLevel(mozc::RunLevel::SERVER);

  if (run_level >= mozc::RunLevel::DENY) {
    LOG(FATAL) << "Do not execute Mozc server as high authority";
    return;
  }

  if (mozc::config::StatsConfigUtil::IsEnabled()) {
    mozc::CrashReportHandler::Initialize(false);
  }
  InitGoogle(arg0, argc, argv, remove_flags);

  if (run_level == mozc::RunLevel::RESTRICTED) {
    VLOG(1) << "Mozc server starts with timeout mode";
    FLAGS_restricted = true;
  }

  return;
}

int MozcServer::Run() {
  string mutex_name = "server";
  mozc::ProcessMutex mutex(mutex_name.c_str());
  if (!mutex.Lock()) {
    LOG(INFO) << "Mozc Server is already running";
    return -1;
  }

  {
    scoped_ptr<mozc::SessionServer> session_server
        (new mozc::SessionServer);
    g_session_server = session_server.get();
    CHECK(g_session_server);
    if (!g_session_server->Connected()) {
      LOG(ERROR) << "SessionServer initialization failed";
      return -1;
    }

#if defined(OS_WIN)
    // On Windows, ShutdownSessionCallback is not called intentionally in order
    // to avoid crashes oritinates from it. See b/2696087.
    g_session_server->Loop();
#else
    // Create a new thread.
    // We can't call Loop() as Loop() doesn't make a thread.
    // We have to make a thread here so that ShutdownSessionCallback()
    // is called properly.
    g_session_server->LoopAndReturn();

    // Wait until the session server thread finishes.
    g_session_server->Wait();
#endif
  }

  return 0;
}

int MozcServer::Finalize() {
  mozc::RunFinalizers();
  return 0;
}

}  // namespace server
}  // namespace mozc