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/*
Copyright 2016-2023 melonDS team
This file is part of melonDS.
melonDS is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option)
any later version.
melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with melonDS. If not, see http://www.gnu.org/licenses/.
*/
#include <stdio.h>
#include <string.h>
#include "SaveManager.h"
#include "Platform.h"
using namespace Platform;
SaveManager::SaveManager(const std::string& path) : QThread()
{
SecondaryBuffer = nullptr;
SecondaryBufferLength = 0;
SecondaryBufferLock = new QMutex();
Running = false;
Path = path;
Buffer = nullptr;
Length = 0;
FlushRequested = false;
FlushVersion = 0;
PreviousFlushVersion = 0;
TimeAtLastFlushRequest = 0;
if (!path.empty())
{
Running = true;
start();
}
}
SaveManager::~SaveManager()
{
if (Running)
{
Running = false;
wait();
FlushSecondaryBuffer();
}
SecondaryBuffer = nullptr;
delete SecondaryBufferLock;
Buffer = nullptr;
}
std::string SaveManager::GetPath()
{
return Path;
}
void SaveManager::SetPath(const std::string& path, bool reload)
{
Path = path;
if (reload)
{ // If we should load whatever file is at the new path...
if (FileHandle* f = Platform::OpenFile(Path, FileMode::Read))
{
if (u32 length = Platform::FileLength(f); length != Length)
{ // If the new file is a different size, we need to re-allocate the buffer.
Length = length;
Buffer = std::make_unique<u8[]>(Length);
}
FileRead(Buffer.get(), 1, Length, f);
CloseFile(f);
}
}
else
FlushRequested = true;
}
void SaveManager::RequestFlush(const u8* savedata, u32 savelen, u32 writeoffset, u32 writelen)
{
if (Length != savelen)
{
Length = savelen;
Buffer = std::make_unique<u8[]>(Length);
memcpy(Buffer.get(), savedata, Length);
}
else
{
if ((writeoffset+writelen) > savelen)
{
u32 len = savelen - writeoffset;
memcpy(&Buffer[writeoffset], &savedata[writeoffset], len);
len = writelen - len;
if (len > savelen) len = savelen;
memcpy(&Buffer[0], &savedata[0], len);
}
else
{
memcpy(&Buffer[writeoffset], &savedata[writeoffset], writelen);
}
}
FlushRequested = true;
}
void SaveManager::CheckFlush()
{
if (!FlushRequested) return;
SecondaryBufferLock->lock();
Log(LogLevel::Info, "SaveManager: Flush requested\n");
if (SecondaryBufferLength != Length)
{
SecondaryBufferLength = Length;
SecondaryBuffer = std::make_unique<u8[]>(SecondaryBufferLength);
}
memcpy(SecondaryBuffer.get(), Buffer.get(), Length);
FlushRequested = false;
FlushVersion++;
TimeAtLastFlushRequest = time(nullptr);
SecondaryBufferLock->unlock();
}
void SaveManager::run()
{
for (;;)
{
QThread::msleep(100);
if (!Running) return;
// We debounce for two seconds after last flush request to ensure that writing has finished.
if (TimeAtLastFlushRequest == 0 || difftime(time(nullptr), TimeAtLastFlushRequest) < 2)
{
continue;
}
FlushSecondaryBuffer();
}
}
void SaveManager::FlushSecondaryBuffer(u8* dst, u32 dstLength)
{
if (!SecondaryBuffer) return;
// When flushing to a file, there's no point in re-writing the exact same data.
if (!dst && !NeedsFlush()) return;
// When flushing to memory, we don't know if dst already has any data so we only check that we CAN flush.
if (dst && dstLength < SecondaryBufferLength) return;
SecondaryBufferLock->lock();
if (dst)
{
memcpy(dst, SecondaryBuffer.get(), SecondaryBufferLength);
}
else
{
FileHandle* f = Platform::OpenFile(Path, FileMode::Write);
if (f)
{
FileWrite(SecondaryBuffer.get(), SecondaryBufferLength, 1, f);
Log(LogLevel::Info, "SaveManager: Wrote %u bytes to %s\n", SecondaryBufferLength, Path.c_str());
CloseFile(f);
}
}
PreviousFlushVersion = FlushVersion;
TimeAtLastFlushRequest = 0;
SecondaryBufferLock->unlock();
}
bool SaveManager::NeedsFlush()
{
return FlushVersion != PreviousFlushVersion;
}
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