/// <summary>
/// Filter supplied <c>folders</c>, removing any folder which itself, or one
/// of its ancestors, is excluded by the <c>filter</c>.
/// </summary>
/// <param name="folders">Folder to filter</param>
/// <param name="filter">Exclusion filter</param>
/// <param name="cache">Cache of excluded folders (optional)</param>
/// <param name="errorCallback"></param>
/// <returns>Filtered folders</returns>
private IEnumerable <string> FilterExcludedFolders(IEnumerable <string> folders,
Utility.Utility.EnumerationFilterDelegate filter, IDictionary <string, bool> cache, Utility.Utility.ReportAccessError errorCallback = null)
{
var result = new List <string>();
foreach (var folder in folders)
{
if (m_token.IsCancellationRequested)
{
break;
}
try
{
if (!IsFolderOrAncestorsExcluded(folder, filter, cache))
{
result.Add(folder);
}
}
catch (System.Threading.ThreadAbortException)
{
throw;
}
catch (Exception ex)
{
errorCallback?.Invoke(folder, folder, ex);
filter(folder, folder, FileAttributes.Directory | Utility.Utility.ATTRIBUTE_ERROR);
}
}
return(result);
}
/// <summary>
/// Filter supplied <c>files</c>, removing any files which itself, or one
/// of its parent folders, is excluded by the <c>filter</c>.
/// </summary>
/// <param name="files">Files to filter</param>
/// <param name="filter">Exclusion filter</param>
/// <param name="cache">Cache of included and exculded files / folders</param>
/// <param name="errorCallback"></param>
/// <returns>Filtered files</returns>
private IEnumerable <string> FilterExcludedFiles(IEnumerable <string> files,
Utility.Utility.EnumerationFilterDelegate filter, IDictionary <string, bool> cache, Utility.Utility.ReportAccessError errorCallback = null)
{
var result = new List <string>();
foreach (var file in files)
{
var attr = m_snapshot.FileExists(file) ? m_snapshot.GetAttributes(file) : FileAttributes.Normal;
try
{
if (!filter(file, file, attr))
{
continue;
}
if (!IsFolderOrAncestorsExcluded(Utility.Utility.GetParent(file, true), filter, cache))
{
result.Add(file);
}
}
catch (System.Threading.ThreadAbortException)
{
throw;
}
catch (Exception ex)
{
errorCallback?.Invoke(file, file, ex);
filter(file, file, attr | Utility.Utility.ATTRIBUTE_ERROR);
}
}
return(result);
}
/// <summary>
/// Filters sources, returning sub-set having been modified since last
/// change, as specified by <c>journalData</c>.
/// </summary>
/// <param name="filter">Filter callback to exclude filtered items</param>
/// <returns>Filtered sources</returns>
public IEnumerable <string> GetModifiedSources(Utility.Utility.EnumerationFilterDelegate filter)
{
// iterate over volumes
foreach (var volumeData in m_volumeDataDict)
{
// prepare cache for includes (value = true) and excludes (value = false, will be populated
// on-demand)
var cache = new Dictionary <string, bool>();
foreach (var source in m_sources)
{
if (m_token.IsCancellationRequested)
{
break;
}
cache[source] = true;
}
// Check the simplified folders, and their parent folders against the exclusion filter.
// This is needed because the filter may exclude "C:\A\", but this won't match the more
// specific "C:\A\B\" in our list, even though it's meant to be excluded.
// The reason why the filter doesn't exclude it is because during a regular (non-USN) full scan,
// FilterHandler.EnumerateFilesAndFolders() works top-down, and won't even enumerate child
// folders.
// The sources are needed to stop evaluating parent folders above the specified source folders
if (volumeData.Value.Folders != null)
{
foreach (var folder in FilterExcludedFolders(volumeData.Value.Folders, filter, cache).Where(m_snapshot.DirectoryExists))
{
if (m_token.IsCancellationRequested)
{
break;
}
yield return(folder);
}
}
// The simplified file list also needs to be checked against the exclusion filter, as it
// may contain entries excluded due to attributes, but also because they are below excluded
// folders, which themselves aren't in the folder list from step 1.
// Note that the simplified file list may contain entries that have been deleted! They need to
// be kept in the list (unless excluded by the filter) in order for the backup handler to record their
// deletion.
if (volumeData.Value.Files != null)
{
foreach (var files in FilterExcludedFiles(volumeData.Value.Files, filter, cache).Where(m_snapshot.FileExists))
{
if (m_token.IsCancellationRequested)
{
break;
}
yield return(files);
}
}
}
}
/// <summary>
/// Tests if specified folder, or any of its ancestors, is excluded by the filter
/// </summary>
/// <param name="folder">Folder to test</param>
/// <param name="filter">Filter</param>
/// <param name="cache">Cache of excluded folders (optional)</param>
/// <returns>True if excluded, false otherwise</returns>
private bool IsFolderOrAncestorsExcluded(string folder, Utility.Utility.EnumerationFilterDelegate filter, IDictionary <string, bool> cache)
{
List <string> parents = null;
while (folder != null)
{
if (m_token.IsCancellationRequested)
{
break;
}
// first check cache
if (cache.TryGetValue(folder, out var include))
{
if (include)
{
return(false);
}
break; // hit!
}
// remember folder for cache
if (parents == null)
{
parents = new List <string>(); // create on-demand
}
parents.Add(folder);
var attr = m_snapshot.DirectoryExists(folder) ? m_snapshot.GetAttributes(folder) : FileAttributes.Directory;
if (!filter(folder, folder, attr))
{
break; // excluded
}
folder = Utility.Utility.GetParent(folder, true);
}
if (folder != null)
{
// update cache
parents?.ForEach(p => cache[p] = false);
}
return(folder != null);
}
/// <summary>
/// Enumerates all files and folders in the shadow copy
/// </summary>
/// <param name="sources">Source paths to enumerate</param>
/// <param name="callback">The callback to invoke with each found path</param>
/// <param name="errorCallback">The callback used to report errors</param>
public IEnumerable <string> EnumerateFilesAndFolders(IEnumerable <string> sources, Utility.Utility.EnumerationFilterDelegate callback, Utility.Utility.ReportAccessError errorCallback)
{
return(sources.SelectMany(s => Utility.Utility.EnumerateFileSystemEntries(s, callback, ListFolders, ListFiles, GetAttributes, errorCallback)));
}
/// <summary>
/// Enumerates all files and folders in the shadow copy
/// </summary>
/// <param name="sources">Source paths to enumerate</param>
/// <param name="callback">The callback to invoke with each found path</param>
/// <param name="errorCallback">The callback used to report errors</param>
public IEnumerable <string> EnumerateFilesAndFolders(IEnumerable <string> sources, Utility.Utility.EnumerationFilterDelegate callback, Utility.Utility.ReportAccessError errorCallback)
{
// Add trailing slashes to folders
var sanitizedSources = sources.Select(x => DirectoryExists(x) ? Utility.Utility.AppendDirSeparator(x) : x).ToList();
return(sanitizedSources.SelectMany(
s => Utility.Utility.EnumerateFileSystemEntries(s, callback, ListFolders, ListFiles, GetAttributes, errorCallback)
));
}
/// <summary>
/// Enumerates all files and folders in the snapshot, restricted to sources
/// </summary>
/// <param name="sources">Sources to enumerate</param>
/// <param name="callback">The callback to invoke with each found path</param>
/// <param name="errorCallback">The callback used to report errors</param>
public override IEnumerable <string> EnumerateFilesAndFolders(IEnumerable <string> sources, Utility.Utility.EnumerationFilterDelegate callback, Utility.Utility.ReportAccessError errorCallback)
{
// For Windows, ensure we don't store paths with UNC prefix
return(base.EnumerateFilesAndFolders(sources.Select(SystemIOWindows.StripUNCPrefix), callback, errorCallback));
}
/// <summary>
/// Enumerates all files and folders in the snapshot, restricted to sources
/// </summary>
/// <param name="sources">Sources to enumerate</param>
/// <param name="callback">The callback to invoke with each found path</param>
/// <param name="errorCallback">The callback used to report errors</param>
public override IEnumerable <string> EnumerateFilesAndFolders(IEnumerable <string> sources, Utility.Utility.EnumerationFilterDelegate callback, Utility.Utility.ReportAccessError errorCallback)
{
// For Windows, ensure we don't store paths with extended device path prefixes (i.e., @"\\?\" or @"\\?\UNC\")
return(base.EnumerateFilesAndFolders(sources.Select(SystemIOWindows.RemoveExtendedDevicePathPrefix), callback, errorCallback));
}
