/// <summary>
/// Returns a possibly-empty list of incorrect entries in this <see cref="FileContentTable" />.
/// </summary>
/// <remarks>
/// In the absence of an incorrect file content table implementation, file system bugs, or disk corruption, the list should
/// be empty.
/// Hence, this is a diagnostic facility.
/// </remarks>
public static List <IncorrectFileContentEntry> FindIncorrectEntries(this FileContentTable fileContentTable, IFileContentTableAccessor accessor)
{
Contract.Requires(fileContentTable != null);
Contract.Requires(accessor != null);
Contract.Ensures(Contract.Result <List <IncorrectFileContentEntry> >() != null);
Contract.Ensures(Contract.ForAll(Contract.Result <List <IncorrectFileContentEntry> >(), e => e != null));
var badEntries = new List <IncorrectFileContentEntry>();
fileContentTable.VisitKnownFiles(
accessor,
FileShare.Read | FileShare.Delete,
// On accessing the entry of file content table, we do not allow concurrent writes; otherwise the content may change as we're hashing it.
// To this end, the file needs to be opened with FileShare.Read | FileShare.Delete accesses.
(fileIdAndVolumeId, handle, path, knownUsn, knownHash) =>
{
using (var fs = new FileStream(handle, FileAccess.Read))
{
ContentHash actualHash = ContentHashingUtilities.HashContentStreamAsync(fs).GetAwaiter().GetResult();
if (knownHash != actualHash)
{
badEntries.Add(new IncorrectFileContentEntry(path, fileIdAndVolumeId, knownUsn, knownHash, actualHash));
}
}
return(true);
});
return(badEntries);
}
