/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

 * vim: set ts=8 sts=4 et sw=4 tw=99:

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* Extensions to the Result type to enable simpler handling of XPCOM/NSPR

 * results. */

#ifndef mozilla_ResultExtensions_h

#define mozilla_ResultExtensions_h

#include "mozilla/Assertions.h"

#include "nscore.h"

#include "prtypes.h"

namespace mozilla {

// Allow nsresult errors to automatically convert to nsresult values, so MOZ_TRY

// can be used in XPCOM methods with Result<T, nserror> results.

template <>

class MOZ_MUST_USE_TYPE GenericErrorResult<nsresult> {

  nsresult mErrorValue;

  template <typename V, typename E2>

  friend class Result;

 public:

  explicit GenericErrorResult(nsresult aErrorValue) : mErrorValue(aErrorValue) {

    MOZ_ASSERT(NS_FAILED(aErrorValue));

  }

  operator nsresult() { return mErrorValue; }

};

// Allow MOZ_TRY to handle `PRStatus` values.

inline Result<Ok, nsresult> ToResult(PRStatus aValue);

}  // namespace mozilla

#include "mozilla/Result.h"

namespace mozilla {

inline Result<Ok, nsresult> ToResult(nsresult aValue) {

  if (NS_FAILED(aValue)) {

    return Err(aValue);

  }

  return Ok();

}

inline Result<Ok, nsresult> ToResult(PRStatus aValue) {

  if (aValue == PR_SUCCESS) {

    return Ok();

  }

  return Err(NS_ERROR_FAILURE);

}

}  // namespace mozilla

#endif  // mozilla_ResultExtensions_h