gecko-dev/mfbt/ResultExtensions.h
Kris Maglione c9899cb3fa Bug 1366511: Part 2 - Allow autoconverting Err(nsresult) to nsresult. r=ehsan,nbp
This allows MOZ_TRY and MOZ_TRY_VAR to be transparently used in XPCOM methods
when compatible Result types are used.

Also removes a compatibility macro in SimpleChannel.cpp, and an identical
specialization in AddonManagerStartup, which are no longer necessary after
this change.

MozReview-Commit-ID: 94iNrPDJEnN

--HG--
extra : rebase_source : 24ad4a54cbd170eb04ded21794530e56b1dfbd82
2017-08-29 21:28:22 -07:00

38 lines
1.1 KiB
C++

/* -*- 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"
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; }
};
} // namespace mozilla
#endif // mozilla_ResultExtensions_h