Files
rippled/modules/beast_core/misc/beast_Result.h
2013-07-23 13:04:52 -07:00

120 lines
3.9 KiB
C++

//------------------------------------------------------------------------------
/*
This file is part of Beast: https://github.com/vinniefalco/Beast
Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
Portions of this file are from JUCE.
Copyright (c) 2013 - Raw Material Software Ltd.
Please visit http://www.juce.com
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#ifndef BEAST_RESULT_BEASTHEADER
#define BEAST_RESULT_BEASTHEADER
#include "../text/beast_String.h"
/** Represents the 'success' or 'failure' of an operation, and holds an associated
error message to describe the error when there's a failure.
E.g.
@code
Result myOperation()
{
if (doSomeKindOfFoobar())
return Result::ok();
else
return Result::fail ("foobar didn't work!");
}
const Result result (myOperation());
if (result.wasOk())
{
...it's all good...
}
else
{
warnUserAboutFailure ("The foobar operation failed! Error message was: "
+ result.getErrorMessage());
}
@endcode
*/
class BEAST_API Result
{
public:
//==============================================================================
/** Creates and returns a 'successful' result. */
static Result ok() noexcept { return Result(); }
/** Creates a 'failure' result.
If you pass a blank error message in here, a default "Unknown Error" message
will be used instead.
*/
static Result fail (const String& errorMessage) noexcept;
//==============================================================================
/** Returns true if this result indicates a success. */
bool wasOk() const noexcept;
/** Returns true if this result indicates a failure.
You can use getErrorMessage() to retrieve the error message associated
with the failure.
*/
bool failed() const noexcept;
/** Returns true if this result indicates a success.
This is equivalent to calling wasOk().
*/
operator bool() const noexcept;
/** Returns true if this result indicates a failure.
This is equivalent to calling failed().
*/
bool operator!() const noexcept;
/** Returns the error message that was set when this result was created.
For a successful result, this will be an empty string;
*/
const String& getErrorMessage() const noexcept;
//==============================================================================
Result (const Result&);
Result& operator= (const Result&);
#if BEAST_COMPILER_SUPPORTS_MOVE_SEMANTICS
Result (Result&&) noexcept;
Result& operator= (Result&&) noexcept;
#endif
bool operator== (const Result& other) const noexcept;
bool operator!= (const Result& other) const noexcept;
private:
String errorMessage;
// The default constructor is not for public use!
// Instead, use Result::ok() or Result::fail()
Result() noexcept;
explicit Result (const String&) noexcept;
// These casts are private to prevent people trying to use the Result object in numeric contexts
operator int() const;
operator void*() const;
};
#endif