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/* -*- 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/. */
/**
* LookupResult is the return type of SurfaceCache's Lookup*() functions. It
* combines a surface with relevant metadata tracked by SurfaceCache.
*/
#ifndef mozilla_image_LookupResult_h
#define mozilla_image_LookupResult_h
#include <utility>
#include "ISurfaceProvider.h"
#include "mozilla/Attributes.h"
#include "mozilla/gfx/Point.h" // for IntSize
namespace mozilla {
namespace image {
enum class MatchType : uint8_t {
NOT_FOUND, // No matching surface and no placeholder.
PENDING, // Found a matching placeholder, but no surface.
EXACT, // Found a surface that matches exactly.
SUBSTITUTE_BECAUSE_NOT_FOUND, // No exact match, but found a similar one.
SUBSTITUTE_BECAUSE_PENDING, // Found a similar surface and a placeholder
// for an exact match.
/* No exact match, but this should be considered an exact match for purposes
* of deciding whether or not to request a new decode. This is because the
* cache has determined that callers require too many size variants of this
* image. It determines the set of sizes which best represent the image, and
* will only suggest decoding of unavailable sizes from that set. */
SUBSTITUTE_BECAUSE_BEST
};
/**
* LookupResult is the return type of SurfaceCache's Lookup*() functions. It
* combines a surface with relevant metadata tracked by SurfaceCache.
*/
class MOZ_STACK_CLASS LookupResult {
public:
explicit LookupResult(MatchType aMatchType)
: mMatchType(aMatchType), mFailedToRequestDecode(false) {
MOZ_ASSERT(
mMatchType == MatchType::NOT_FOUND || mMatchType == MatchType::PENDING,
"Only NOT_FOUND or PENDING make sense with no surface");
}
LookupResult(LookupResult&& aOther)
: mSurface(std::move(aOther.mSurface)),
mMatchType(aOther.mMatchType),
mSuggestedSize(aOther.mSuggestedSize),
mFailedToRequestDecode(aOther.mFailedToRequestDecode) {}
LookupResult(DrawableSurface&& aSurface, MatchType aMatchType)
: mSurface(std::move(aSurface)),
mMatchType(aMatchType),
mFailedToRequestDecode(false) {
MOZ_ASSERT(!mSurface || !(mMatchType == MatchType::NOT_FOUND ||
mMatchType == MatchType::PENDING),
"Only NOT_FOUND or PENDING make sense with no surface");
MOZ_ASSERT(mSurface || mMatchType == MatchType::NOT_FOUND ||
mMatchType == MatchType::PENDING,
"NOT_FOUND or PENDING do not make sense with a surface");
}
LookupResult(MatchType aMatchType, const gfx::IntSize& aSuggestedSize)
: mMatchType(aMatchType),
mSuggestedSize(aSuggestedSize),
mFailedToRequestDecode(false) {
MOZ_ASSERT(
mMatchType == MatchType::NOT_FOUND || mMatchType == MatchType::PENDING,
"Only NOT_FOUND or PENDING make sense with no surface");
}
LookupResult(DrawableSurface&& aSurface, MatchType aMatchType,
const gfx::IntSize& aSuggestedSize)
: mSurface(std::move(aSurface)),
mMatchType(aMatchType),
mSuggestedSize(aSuggestedSize),
mFailedToRequestDecode(false) {
MOZ_ASSERT(!mSurface || !(mMatchType == MatchType::NOT_FOUND ||
mMatchType == MatchType::PENDING),
"Only NOT_FOUND or PENDING make sense with no surface");
MOZ_ASSERT(mSurface || mMatchType == MatchType::NOT_FOUND ||
mMatchType == MatchType::PENDING,
"NOT_FOUND or PENDING do not make sense with a surface");
}
LookupResult& operator=(LookupResult&& aOther) {
MOZ_ASSERT(&aOther != this, "Self-move-assignment is not supported");
mSurface = std::move(aOther.mSurface);
mMatchType = aOther.mMatchType;
mSuggestedSize = aOther.mSuggestedSize;
mFailedToRequestDecode = aOther.mFailedToRequestDecode;
return *this;
}
DrawableSurface& Surface() { return mSurface; }
const DrawableSurface& Surface() const { return mSurface; }
const gfx::IntSize& SuggestedSize() const { return mSuggestedSize; }
/// @return true if this LookupResult contains a surface.
explicit operator bool() const { return bool(mSurface); }
/// @return what kind of match this is (exact, substitute, etc.)
MatchType Type() const { return mMatchType; }
void SetFailedToRequestDecode() { mFailedToRequestDecode = true; }
bool GetFailedToRequestDecode() { return mFailedToRequestDecode; }
private:
LookupResult(const LookupResult&) = delete;
LookupResult& operator=(const LookupResult& aOther) = delete;
DrawableSurface mSurface;
MatchType mMatchType;
/// mSuggestedSize will be the size of the returned surface if the result is
/// SUBSTITUTE_BECAUSE_BEST. It will be empty for EXACT, and can contain a
/// non-empty size possibly different from the returned surface (if any) for
/// all other results. If non-empty, it will always be the size the caller
/// should request any decodes at.
gfx::IntSize mSuggestedSize;
// True if we tried to start a decode but failed, likely because the image was
// too big to fit into the surface cache.
bool mFailedToRequestDecode;
};
} // namespace image
} // namespace mozilla
#endif // mozilla_image_LookupResult_h