/// <summary> Construct from a read-only file. </summary>
/// <remarks>
/// Used when recovering files written by a previous program
/// instance from their locations.
/// </remarks>
public BlockFile(IFileMemory file, uint fileId)
{
_pinner = new Pinner();
_file = file ?? throw new ArgumentNullException(nameof(file));
FileId = fileId;
_flags = new AppendList <ReadFlag>();
var offset = 0L;
while (offset < _file.Length)
{
var block = AtOffset(offset);
ref var header = ref block.Header;
if (header.Rank != _flags.Count || header.ContentLength < 0 ||
header.ContentLength + BlockHeader.Size > _file.Length)
{
// The header of the block appears broken. Do not include
// it in the list, and stop scanning (since we don't know
// how far to jump ahead).
break;
}
var thisOffset = offset;
_flags.Append(ReadFlag.Triggered(() => VerifyAtOffset(thisOffset)));
offset += block.RelativeOffsetToNextBlock;
}
/// <summary> Construct from raw building blocks. </summary>
/// <remarks>
/// Used to create a read-only view over a file that is being written to.
/// Note that <see cref="_flags"/> may grow over time, as new blocks are
/// appended.
/// </remarks>
internal BlockFile(
IFileMemory file,
AppendList <ReadFlag> flags,
uint fileId)
{
_file = file ?? throw new ArgumentNullException(nameof(file));
_flags = flags ?? throw new ArgumentNullException(nameof(flags));
FileId = fileId;
}
private FileWriter(IFileMemory file, AppendList <ReadFlag> flags, uint fileId)
{
_file = file;
_flags = flags;
FileId = fileId;
}
