/// <summary>
/// Recovers an interrupted multi-commit. The commit will either be completed or rolled back depending on
/// where in the commit process it was interrupted. Does nothing if there is no commit to recover.
/// </summary>
/// <param name="multiCommitInterface">The core interface used for multi-commits.</param>
/// <param name="saveService">The save data service.</param>
/// <returns>The <see cref="Result"/> of the operation.<br/>
/// <see cref="Result.Success"/>: The recovery was successful or there was no multi-commit to recover.</returns>
public static Result Recover(ISaveDataMultiCommitCoreInterface multiCommitInterface,
SaveDataFileSystemServiceImpl saveService)
{
lock (Locker)
{
bool needsRecover = true;
ReferenceCountedDisposable <IFileSystem> fileSystem = null;
try
{
// Check if a multi-commit was interrupted by checking if there's a commit context file.
Result rc = multiCommitInterface.OpenMultiCommitContext(out fileSystem);
if (rc.IsFailure())
{
if (!ResultFs.PathNotFound.Includes(rc) && !ResultFs.TargetNotFound.Includes(rc))
{
return(rc);
}
// Unable to open the multi-commit context file system, so there's nothing to recover
needsRecover = false;
}
if (needsRecover)
{
rc = fileSystem.Target.OpenFile(out IFile file, CommitContextFileName, OpenMode.Read);
file?.Dispose();
if (rc.IsFailure())
{
// Unable to open the context file. No multi-commit to recover.
if (ResultFs.PathNotFound.Includes(rc))
{
needsRecover = false;
}
}
}
if (!needsRecover)
{
return(Result.Success);
}
// There was a context file. Recover the unfinished commit.
return(Recover(multiCommitInterface, fileSystem.Target, saveService));
}
finally
{
fileSystem?.Dispose();
}
}
}
/// <summary>
/// Tries to recover a multi-commit using the context in the provided file system.
/// </summary>
/// <param name="multiCommitInterface">The core interface used for multi-commits.</param>
/// <param name="contextFs">The file system containing the multi-commit context file.</param>
/// <param name="saveService">The save data service.</param>
/// <returns></returns>
private static Result Recover(ISaveDataMultiCommitCoreInterface multiCommitInterface, IFileSystem contextFs,
SaveDataFileSystemServiceImpl saveService)
{
if (multiCommitInterface is null)
{
return(ResultFs.InvalidArgument.Log());
}
if (contextFs is null)
{
return(ResultFs.InvalidArgument.Log());
}
// Keep track of the first error that occurs during the recovery
Result recoveryResult = Result.Success;
Result rc = RecoverCommit(multiCommitInterface, contextFs, saveService);
if (rc.IsFailure())
{
// Note: Yes, the next ~50 lines are exactly the same as the code in RecoverCommit except
// for a single bool value. No, Nintendo doesn't split it out into its own function.
int saveCount = 0;
Span <SaveDataInfo> savesToRecover = stackalloc SaveDataInfo[MaxFileSystemCount];
SaveDataIndexerAccessor accessor = null;
ReferenceCountedDisposable <SaveDataInfoReaderImpl> infoReader = null;
try
{
rc = saveService.OpenSaveDataIndexerAccessor(out accessor, out _, SaveDataSpaceId.User);
if (rc.IsFailure())
{
return(rc);
}
rc = accessor.Indexer.OpenSaveDataInfoReader(out infoReader);
if (rc.IsFailure())
{
return(rc);
}
// Iterate through all the saves to find any provisionally committed save data
while (true)
{
Unsafe.SkipInit(out SaveDataInfo info);
rc = infoReader.Target.Read(out long readCount, OutBuffer.FromStruct(ref info));
if (rc.IsFailure())
{
return(rc);
}
// Break once we're done iterating all save data
if (readCount == 0)
{
break;
}
rc = multiCommitInterface.IsProvisionallyCommittedSaveData(out bool isProvisionallyCommitted,
in info);
// Note: Some saves could be missed if there are more than MaxFileSystemCount
// provisionally committed saves. Not sure why Nintendo doesn't catch this.
if (rc.IsSuccess() && isProvisionallyCommitted && saveCount < MaxFileSystemCount)
{
savesToRecover[saveCount] = info;
saveCount++;
}
}
}
finally
{
accessor?.Dispose();
infoReader?.Dispose();
}
// Recover the saves by rolling them back to the previous commit.
// All file systems will try to be recovered, even if one fails.
// If any commits fail, the result from the first failed recovery will be returned.
for (int i = 0; i < saveCount; i++)
{
rc = multiCommitInterface.RecoverProvisionallyCommittedSaveData(in savesToRecover[i], true);
if (recoveryResult.IsSuccess() && rc.IsFailure())
{
recoveryResult = rc;
}
}
}
// Delete the commit context file
rc = contextFs.DeleteFile(CommitContextFileName);
if (rc.IsFailure())
{
return(rc);
}
rc = contextFs.Commit();
if (rc.IsFailure())
{
return(rc);
}
return(recoveryResult);
}
/// <summary>
/// Recovers a multi-commit that was interrupted after all file systems had been provisionally committed.
/// The recovery will finish committing any file systems that are still provisionally committed.
/// </summary>
/// <param name="multiCommitInterface">The core interface used for multi-commits.</param>
/// <param name="contextFs">The file system containing the multi-commit context file.</param>
/// <param name="saveService">The save data service.</param>
/// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
/// <see cref="ResultFs.InvalidMultiCommitContextVersion"/>: The version of the commit context
/// file isn't supported.<br/>
/// <see cref="ResultFs.InvalidMultiCommitContextState"/>: The multi-commit hadn't finished
/// provisionally committing all the file systems.</returns>
private static Result RecoverCommit(ISaveDataMultiCommitCoreInterface multiCommitInterface,
IFileSystem contextFs, SaveDataFileSystemServiceImpl saveService)
{
IFile contextFile = null;
try
{
// Read the multi-commit context
Result rc = contextFs.OpenFile(out contextFile, CommitContextFileName, OpenMode.ReadWrite);
if (rc.IsFailure())
{
return(rc);
}
Unsafe.SkipInit(out Context context);
rc = contextFile.Read(out _, 0, SpanHelpers.AsByteSpan(ref context), ReadOption.None);
if (rc.IsFailure())
{
return(rc);
}
// Note: Nintendo doesn't check if the proper amount of bytes were read, but it
// doesn't really matter since the context is validated.
if (context.Version > CurrentCommitContextVersion)
{
return(ResultFs.InvalidMultiCommitContextVersion.Log());
}
// All the file systems in the multi-commit must have been at least provisionally committed
// before we can try to recover the commit.
if (context.State != CommitState.ProvisionallyCommitted)
{
return(ResultFs.InvalidMultiCommitContextState.Log());
}
// Keep track of the first error that occurs during the recovery
Result recoveryResult = Result.Success;
int saveCount = 0;
Span <SaveDataInfo> savesToRecover = stackalloc SaveDataInfo[MaxFileSystemCount];
SaveDataIndexerAccessor accessor = null;
ReferenceCountedDisposable <SaveDataInfoReaderImpl> infoReader = null;
try
{
rc = saveService.OpenSaveDataIndexerAccessor(out accessor, out _, SaveDataSpaceId.User);
if (rc.IsFailure())
{
return(rc);
}
rc = accessor.Indexer.OpenSaveDataInfoReader(out infoReader);
if (rc.IsFailure())
{
return(rc);
}
// Iterate through all the saves to find any provisionally committed save data
while (true)
{
Unsafe.SkipInit(out SaveDataInfo info);
rc = infoReader.Target.Read(out long readCount, OutBuffer.FromStruct(ref info));
if (rc.IsFailure())
{
return(rc);
}
// Break once we're done iterating all save data
if (readCount == 0)
{
break;
}
rc = multiCommitInterface.IsProvisionallyCommittedSaveData(out bool isProvisionallyCommitted,
in info);
// Note: Some saves could be missed if there are more than MaxFileSystemCount
// provisionally committed saves. Not sure why Nintendo doesn't catch this.
if (rc.IsSuccess() && isProvisionallyCommitted && saveCount < MaxFileSystemCount)
{
savesToRecover[saveCount] = info;
saveCount++;
}
}
}
finally
{
accessor?.Dispose();
infoReader?.Dispose();
}
// Recover the saves by finishing their commits.
// All file systems will try to be recovered, even if one fails.
// If any commits fail, the result from the first failed recovery will be returned.
for (int i = 0; i < saveCount; i++)
{
rc = multiCommitInterface.RecoverProvisionallyCommittedSaveData(in savesToRecover[i], false);
if (recoveryResult.IsSuccess() && rc.IsFailure())
{
recoveryResult = rc;
}
}
return(recoveryResult);
}
finally
{
contextFile?.Dispose();
}
}