mirror of
https://github.com/classilla/tenfourfox.git
synced 2024-09-09 20:54:40 +00:00
90 lines
3.0 KiB
C
90 lines
3.0 KiB
C
|
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
||
|
/* 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/. */
|
||
|
|
||
|
#ifndef mozilla_image_DrawResult_h
|
||
|
#define mozilla_image_DrawResult_h
|
||
|
|
||
|
#include "mozilla/Attributes.h"
|
||
|
#include "mozilla/Likely.h"
|
||
|
|
||
|
namespace mozilla {
|
||
|
namespace image {
|
||
|
|
||
|
/**
|
||
|
* An enumeration representing the result of a drawing operation.
|
||
|
*
|
||
|
* Most users of DrawResult will only be interested in whether the value is
|
||
|
* SUCCESS or not. The other values are primarily useful for debugging and error
|
||
|
* handling.
|
||
|
*
|
||
|
* SUCCESS: We successfully drew a completely decoded frame of the requested
|
||
|
* size. Drawing again with FLAG_SYNC_DECODE would not change the result.
|
||
|
*
|
||
|
* INCOMPLETE: We successfully drew a frame that was partially decoded. (Note
|
||
|
* that successfully drawing a partially decoded frame may not actually draw any
|
||
|
* pixels!) Drawing again with FLAG_SYNC_DECODE would improve the result.
|
||
|
*
|
||
|
* WRONG_SIZE: We successfully drew a wrongly-sized frame that had to be scaled.
|
||
|
* This is only returned if drawing again with FLAG_SYNC_DECODE would improve
|
||
|
* the result; if the size requested was larger than the intrinsic size of the
|
||
|
* image, for example, we would generally have to scale whether FLAG_SYNC_DECODE
|
||
|
* was specified or not, and therefore we would not return WRONG_SIZE.
|
||
|
*
|
||
|
* NOT_READY: We failed to draw because no decoded version of the image was
|
||
|
* available. Drawing again with FLAG_SYNC_DECODE would improve the result.
|
||
|
* (Though FLAG_SYNC_DECODE will not necessarily work until after the image's
|
||
|
* load event!)
|
||
|
*
|
||
|
* TEMPORARY_ERROR: We failed to draw due to a temporary error. Drawing may
|
||
|
* succeed at a later time.
|
||
|
*
|
||
|
* BAD_IMAGE: We failed to draw because the image has an error. This is a
|
||
|
* permanent condition.
|
||
|
*
|
||
|
* BAD_ARGS: We failed to draw because bad arguments were passed to draw().
|
||
|
*/
|
||
|
enum class DrawResult : uint8_t
|
||
|
{
|
||
|
SUCCESS,
|
||
|
INCOMPLETE,
|
||
|
WRONG_SIZE,
|
||
|
NOT_READY,
|
||
|
TEMPORARY_ERROR,
|
||
|
BAD_IMAGE,
|
||
|
BAD_ARGS
|
||
|
};
|
||
|
|
||
|
/**
|
||
|
* You can combine DrawResults with &. By analogy to bitwise-&, the result is
|
||
|
* DrawResult::SUCCESS only if both operands are DrawResult::SUCCESS. Otherwise,
|
||
|
* a failing DrawResult is returned; we favor the left operand's failure when
|
||
|
* deciding which failure to return, with the exception that we always prefer
|
||
|
* any other kind of failure over DrawResult::BAD_IMAGE, since other failures
|
||
|
* are recoverable and we want to know if any recoverable failures occurred.
|
||
|
*/
|
||
|
inline DrawResult
|
||
|
operator&(const DrawResult aLeft, const DrawResult aRight)
|
||
|
{
|
||
|
if (MOZ_LIKELY(aLeft == DrawResult::SUCCESS)) {
|
||
|
return aRight;
|
||
|
}
|
||
|
if (aLeft == DrawResult::BAD_IMAGE && aRight != DrawResult::SUCCESS) {
|
||
|
return aRight;
|
||
|
}
|
||
|
return aLeft;
|
||
|
}
|
||
|
|
||
|
inline DrawResult&
|
||
|
operator&=(DrawResult& aLeft, const DrawResult aRight)
|
||
|
{
|
||
|
aLeft = aLeft & aRight;
|
||
|
return aLeft;
|
||
|
}
|
||
|
|
||
|
} // namespace image
|
||
|
} // namespace mozilla
|
||
|
|
||
|
#endif // mozilla_image_DrawResult_h
|