1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-15 04:44:58 +00:00
serenity/Userland/Libraries/LibGfx/ImageDecoder.cpp
Liav A 57e19a7e56 LibGfx: Re-structure the whole initialization pattern for image decoders
When trying to figure out the correct implementation, we now have a very
strong distinction on plugins that are well suited for sniffing, and
plugins that need a MIME type to be chosen.

Instead of having multiple calls to non-static virtual sniff methods for
each Image decoding plugin, we have 2 static methods for each
implementation:
1. The sniff method, which in contrast to the old method, gets a
    ReadonlyBytes parameter and ensures we can figure out the result
    with zero heap allocations for most implementations.
2. The create method, which just creates a new instance so we don't
    expose the constructor to everyone anymore.

In addition to that, we have a new virtual method called initialize,
which has a per-implementation initialization pattern to actually ensure
each implementation can construct a decoder object, and then have a
correct context being applied to it for the actual decoding.
2023-01-20 15:13:31 +00:00

99 lines
3.6 KiB
C++

/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/LexicalPath.h>
#include <LibGfx/BMPLoader.h>
#include <LibGfx/DDSLoader.h>
#include <LibGfx/GIFLoader.h>
#include <LibGfx/ICOLoader.h>
#include <LibGfx/ImageDecoder.h>
#include <LibGfx/JPGLoader.h>
#include <LibGfx/PBMLoader.h>
#include <LibGfx/PGMLoader.h>
#include <LibGfx/PNGLoader.h>
#include <LibGfx/PPMLoader.h>
#include <LibGfx/QOILoader.h>
#include <LibGfx/TGALoader.h>
namespace Gfx {
struct ImagePluginInitializer {
ErrorOr<bool> (*sniff)(ReadonlyBytes) = nullptr;
ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> (*create)(ReadonlyBytes) = nullptr;
};
static constexpr ImagePluginInitializer s_initializers[] = {
{ PNGImageDecoderPlugin::sniff, PNGImageDecoderPlugin::create },
{ GIFImageDecoderPlugin::sniff, GIFImageDecoderPlugin::create },
{ BMPImageDecoderPlugin::sniff, BMPImageDecoderPlugin::create },
{ PBMImageDecoderPlugin::sniff, PBMImageDecoderPlugin::create },
{ PGMImageDecoderPlugin::sniff, PGMImageDecoderPlugin::create },
{ PPMImageDecoderPlugin::sniff, PPMImageDecoderPlugin::create },
{ ICOImageDecoderPlugin::sniff, ICOImageDecoderPlugin::create },
{ JPGImageDecoderPlugin::sniff, JPGImageDecoderPlugin::create },
{ DDSImageDecoderPlugin::sniff, DDSImageDecoderPlugin::create },
{ QOIImageDecoderPlugin::sniff, QOIImageDecoderPlugin::create },
};
struct ImagePluginWithMIMETypeInitializer {
ErrorOr<bool> (*validate_before_create)(ReadonlyBytes) = nullptr;
ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> (*create)(ReadonlyBytes) = nullptr;
StringView mime_type;
};
static constexpr ImagePluginWithMIMETypeInitializer s_initializers_with_mime_type[] = {
{ TGAImageDecoderPlugin::validate_before_create, TGAImageDecoderPlugin::create, "image/x-targa"sv },
};
static OwnPtr<ImageDecoderPlugin> probe_and_sniff_for_appropriate_plugin(ReadonlyBytes bytes)
{
for (auto& plugin : s_initializers) {
auto sniff_result = plugin.sniff(bytes).release_value_but_fixme_should_propagate_errors();
if (!sniff_result)
continue;
auto plugin_decoder = plugin.create(bytes).release_value_but_fixme_should_propagate_errors();
if (plugin_decoder->initialize())
return plugin_decoder;
}
return {};
}
static OwnPtr<ImageDecoderPlugin> probe_and_sniff_for_appropriate_plugin_with_known_mime_type(StringView mime_type, ReadonlyBytes bytes)
{
for (auto& plugin : s_initializers_with_mime_type) {
if (plugin.mime_type != mime_type)
continue;
auto validation_result = plugin.validate_before_create(bytes).release_value_but_fixme_should_propagate_errors();
if (!validation_result)
continue;
auto plugin_decoder = plugin.create(bytes).release_value_but_fixme_should_propagate_errors();
if (plugin_decoder->initialize())
return plugin_decoder;
}
return {};
}
RefPtr<ImageDecoder> ImageDecoder::try_create_for_raw_bytes(ReadonlyBytes bytes, Optional<DeprecatedString> mime_type)
{
OwnPtr<ImageDecoderPlugin> plugin = probe_and_sniff_for_appropriate_plugin(bytes);
if (!plugin) {
if (mime_type.has_value()) {
plugin = probe_and_sniff_for_appropriate_plugin_with_known_mime_type(mime_type.value(), bytes);
if (!plugin)
return {};
} else {
return {};
}
}
return adopt_ref_if_nonnull(new (nothrow) ImageDecoder(plugin.release_nonnull()));
}
ImageDecoder::ImageDecoder(NonnullOwnPtr<ImageDecoderPlugin> plugin)
: m_plugin(move(plugin))
{
}
}