zircon/kernel/object/include/object/suspend_token_dispatcher.h

// Copyright 2018 The Fuchsia Authors
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#ifndef ZIRCON_KERNEL_OBJECT_INCLUDE_OBJECT_SUSPEND_TOKEN_DISPATCHER_H_
#define ZIRCON_KERNEL_OBJECT_INCLUDE_OBJECT_SUSPEND_TOKEN_DISPATCHER_H_

#include <sys/types.h>
#include <zircon/rights.h>
#include <zircon/types.h>

#include <object/dispatcher.h>
#include <object/handle.h>

class SuspendTokenDispatcher final
    : public SoloDispatcher<SuspendTokenDispatcher, ZX_DEFAULT_SUSPEND_TOKEN_RIGHTS> {
 public:
  // Creates a new token which suspends |task|.
  //
  // Returns:
  //   ZX_OK on success
  //   ZX_ERR_NO_MEMORY if the token could not be allocated
  //   ZX_ERR_WRONG_TYPE if |task| is not a supported type
  //   ZX_ERR_NOT_SUPPORTED if |task| is trying to suspend itself
  static zx_status_t Create(fbl::RefPtr<Dispatcher> task,
                            KernelHandle<SuspendTokenDispatcher>* handle, zx_rights_t* rights);

  ~SuspendTokenDispatcher() final;
  zx_obj_type_t get_type() const final { return ZX_OBJ_TYPE_SUSPEND_TOKEN; }
  void on_zero_handles() final;

 private:
  SuspendTokenDispatcher();

  // A lock annotation is unnecessary because the only time |task_| is used is on_zero_handles()
  // and Create(), and the object can only get zero handles once.
  fbl::RefPtr<Dispatcher> task_;
};

#endif  // ZIRCON_KERNEL_OBJECT_INCLUDE_OBJECT_SUSPEND_TOKEN_DISPATCHER_H_