citra/src/core/savestate.cpp

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// Copyright 2020 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include <chrono>
#include <cryptopp/hex.h>
#include "common/archives.h"
#include "common/logging/log.h"
#include "common/scm_rev.h"
#include "common/zstd_compression.h"
#include "core/cheats/cheats.h"
#include "core/core.h"
#include "core/savestate.h"
#include "video_core/video_core.h"
namespace Core {
#pragma pack(push, 1)
struct CSTHeader {
std::array<u8, 4> filetype; /// Unique Identifier to check the file type (always "CST"0x1B)
u64_le program_id; /// ID of the ROM being executed. Also called title_id
std::array<u8, 20> revision; /// Git hash of the revision this savestate was created with
u64_le time; /// The time when this save state was created
std::array<u8, 216> reserved; /// Make heading 256 bytes so it has consistent size
};
static_assert(sizeof(CSTHeader) == 256, "CSTHeader should be 256 bytes");
#pragma pack(pop)
constexpr std::array<u8, 4> header_magic_bytes{{'C', 'S', 'T', 0x1B}};
std::string GetSaveStatePath(u64 program_id, u32 slot) {
return fmt::format("{}{:016X}.{:02d}.cst", FileUtil::GetUserPath(FileUtil::UserPath::StatesDir),
program_id, slot);
}
std::vector<SaveStateInfo> ListSaveStates(u64 program_id) {
std::vector<SaveStateInfo> result;
for (u32 slot = 1; slot <= SaveStateSlotCount; ++slot) {
const auto path = GetSaveStatePath(program_id, slot);
if (!FileUtil::Exists(path)) {
continue;
}
SaveStateInfo info;
info.slot = slot;
FileUtil::IOFile file(path, "rb");
if (!file) {
LOG_ERROR(Core, "Could not open file {}", path);
continue;
}
CSTHeader header;
if (file.GetSize() < sizeof(header)) {
LOG_ERROR(Core, "File too small {}", path);
continue;
}
if (file.ReadBytes(&header, sizeof(header)) != sizeof(header)) {
LOG_ERROR(Core, "Could not read from file {}", path);
continue;
}
if (header.filetype != header_magic_bytes) {
LOG_WARNING(Core, "Invalid save state file {}", path);
continue;
}
info.time = header.time;
if (header.program_id != program_id) {
LOG_WARNING(Core, "Save state file isn't for the current game {}", path);
continue;
}
std::string revision = fmt::format("{:02x}", fmt::join(header.revision, ""));
if (revision == Common::g_scm_rev) {
info.status = SaveStateInfo::ValidationStatus::OK;
} else {
LOG_WARNING(Core, "Save state file created from a different revision {}", path);
info.status = SaveStateInfo::ValidationStatus::RevisionDismatch;
}
result.emplace_back(std::move(info));
}
return result;
}
void System::SaveState(u32 slot) const {
std::ostringstream sstream{std::ios_base::binary};
try {
{
oarchive oa{sstream};
oa&* this;
}
VideoCore::Save(sstream);
} catch (const std::exception& e) {
LOG_ERROR(Core, "Error saving: {}", e.what());
}
const std::string& str{sstream.str()};
auto buffer = Common::Compression::CompressDataZSTDDefault(
reinterpret_cast<const u8*>(str.data()), str.size());
const auto path = GetSaveStatePath(title_id, slot);
if (!FileUtil::CreateFullPath(path)) {
LOG_ERROR(Core, "Could not create path {}", path);
return;
}
FileUtil::IOFile file(path, "wb");
if (!file) {
LOG_ERROR(Core, "Could not open file {}", path);
return;
}
CSTHeader header{};
header.filetype = header_magic_bytes;
header.program_id = title_id;
std::string rev_bytes;
CryptoPP::StringSource(Common::g_scm_rev, true,
new CryptoPP::HexDecoder(new CryptoPP::StringSink(rev_bytes)));
std::memcpy(header.revision.data(), rev_bytes.data(), sizeof(header.revision));
header.time = std::chrono::duration_cast<std::chrono::seconds>(
std::chrono::system_clock::now().time_since_epoch())
.count();
if (file.WriteBytes(&header, sizeof(header)) != sizeof(header)) {
LOG_ERROR(Core, "Could not write to file {}", path);
return;
}
if (file.WriteBytes(buffer.data(), buffer.size()) != buffer.size()) {
LOG_ERROR(Core, "Could not write to file {}", path);
return;
}
}
void System::LoadState(u32 slot) {
const auto path = GetSaveStatePath(title_id, slot);
if (!FileUtil::Exists(path)) {
LOG_ERROR(Core, "File not exist {}", path);
return;
}
std::vector<u8> decompressed;
{
std::vector<u8> buffer(FileUtil::GetSize(path) - sizeof(CSTHeader));
FileUtil::IOFile file(path, "rb");
if (!file) {
LOG_ERROR(Core, "Could not open file {}", path);
return;
}
file.Seek(sizeof(CSTHeader), SEEK_SET); // Skip header
if (file.ReadBytes(buffer.data(), buffer.size()) != buffer.size()) {
LOG_ERROR(Core, "Could not read from file {}", path);
return;
}
decompressed = Common::Compression::DecompressDataZSTD(buffer);
}
std::istringstream sstream{
std::string{reinterpret_cast<char*>(decompressed.data()), decompressed.size()},
std::ios_base::binary};
decompressed.clear();
// When loading, we want to make sure any lingering state gets cleared out before we begin.
// Shutdown, but persist a few things between loads...
Shutdown(true);
// Re-initialize everything like it was before
auto system_mode = this->app_loader->LoadKernelSystemMode();
auto n3ds_mode = this->app_loader->LoadKernelN3dsMode();
Init(*m_emu_window, *system_mode.first, *n3ds_mode.first);
try {
{
iarchive ia{sstream};
ia&* this;
}
VideoCore::Load(sstream);
} catch (const std::exception& e) {
LOG_ERROR(Core, "Error loading: {}", e.what());
}
}
} // namespace Core