// Reset():
/// <summary>Sets the enumerator back to an initial state, where MoveNext() will move to the very first item.</summary>
public void Reset()
{
IsReset = true;
Current = null;
CurrentLevelSearchData = null;
SearchStack.Clear();
} // end Reset()
} // end Reset()
// MoveNext():
/// <summary>Moves the iterator to the next item.</summary>
/// <returns>
/// A <c>bool</c> indicating whether there was, in fact, a next item.
/// Upon success, <c>Current</c> will contain the next item.
/// If the return value is <c>false</c>, there was no next item and <c>Current</c> will be <c>null</c>.
/// Calling this method repeatedly after passing the end of the iteration will have no effect (it will just keep returning <c>false</c>).
/// </returns>
public bool MoveNext()
{
bool returnValue = true; // Set up the return value to default to true.
if (IsReset)
{
// IsReset was true, so we are about to move to the very first item.
IsReset = false; // We aren't going to be reset anymore after this.
// The very first item is the base item itself.
// Set the current item to an object corresponding to that, but in the process
// we also need to look up the path containing that item, and get enumerators for the files and subdirectories inside the base item, if any.
IEnumerator <FileInfo> files;
IEnumerator <DirectoryInfo> subDirectories;
(Current, BaseContainerPath) = getBaseItem(out files, out subDirectories);
if (Current.Type == BackupItemInfo.ItemType.Directory)
{
// The base item is a readable directory, so set the current search level to that directory and set the still-iterating state to true.
CurrentLevelSearchData = new FileSystemWalkLevel(Current.RelativePath, files, subDirectories, true);
IsStillIterating = true;
}
else
{
IsStillIterating = false; // Base item is a file. There is nothing further to enumerate.
}
}
else if (IsStillIterating)
{
// IsReset was false, but IsStillIterating was true. So we are in the middle of an enumeration.
// Iterate over the files and subdirectories, checking each against the inclusion / exclusion rules,
// until we 1) find an included item to return, at which point we set the current item to that and break from the loop;
// or 2) run out of things to iterate through and IsStillIterating becomes false.
while (IsStillIterating)
{
// We will enumerate through the files in this directory first, then subdirectories.
if (CurrentLevelSearchData.Files.MoveNext())
{
// There is still at least one unexamined file in this directory.
// Having moved to the next file, get its path and check it against the rules.
FileInfo file = CurrentLevelSearchData.Files.Current;
string relativePath = Path.Combine(CurrentLevelSearchData.RelativePath, file.Name);
RuleSet.AllowanceType itemAllowance = Rules.checkPath(relativePath, CurrentLevelSearchData.ThisItemAllowedByRules); // CHANGE CODE HERE: handle exceptions
if (itemAllowance == RuleSet.AllowanceType.Allowed)
{
// The file is included according to the rules, so set the current iterator item to point to it, and break from the loop to exit the function.
Current = new BackupItemInfo(BackupItemInfo.ItemType.File, BaseContainerPath, relativePath); // CHANGE CODE HERE: Handle exceptions thrown by BackupItemInfo constructor
break;
}
else
{
continue; // This file is not included according to the rules. Loop back and look at the next one.
}
}
else if (CurrentLevelSearchData.SubDirectories.MoveNext())
{
// There is still at least one unexamined subdirectory in this directory.
// Having moved to the next subdirectory, get a DirectoryInfo object corresponding to it,
// and determine its path relative to the base path.
DirectoryInfo nextLevelDirectory = CurrentLevelSearchData.SubDirectories.Current;
string nextLevelRelativePath = Path.Combine(CurrentLevelSearchData.RelativePath, nextLevelDirectory.Name);
// Try reading the subdirectory, and get enumerators for iterating the files and subdirectories within it.
IEnumerator <FileInfo> nextLevelFiles;
IEnumerator <DirectoryInfo> nextLevelSubDirectories;
bool ableToReadSubDirectory = tryOpeningDirectory(nextLevelDirectory, out nextLevelFiles, out nextLevelSubDirectories);
// Check the path of the subdirectory against the inclusion / exclusion rules.
RuleSet.AllowanceType subDirectoryAllowance = Rules.checkPath(nextLevelRelativePath, CurrentLevelSearchData.ThisItemAllowedByRules); // // CHANGE CODE HERE: handle exceptions
bool subDirectoryAllowedByRules = (subDirectoryAllowance == RuleSet.AllowanceType.Allowed);
// If we are able to read the subdirectory, we will traverse it, too, in our enumeration,
// UNLESS the rules say it is an entire tree that is to be excluded (which is different from disallowing
// just that subdirectory itself but potentially allowing things within it).
// Push the current directory onto the stack of those currently being searched, so we come back to it,
// and make the subdirectory the one to look at the next time through the loop.
if (ableToReadSubDirectory && subDirectoryAllowance != RuleSet.AllowanceType.TreeDisallowed)
{
SearchStack.Push(CurrentLevelSearchData);
CurrentLevelSearchData =
new FileSystemWalkLevel(nextLevelRelativePath, nextLevelFiles, nextLevelSubDirectories, subDirectoryAllowedByRules);
}
// If the subdirectory is allowed by the rules, set it as the current item of this enumerator, and break from the loop to exit the function.
if (subDirectoryAllowedByRules)
{
// CHANGE CODE HERE: Handle exceptions thrown by BackupItemInfo constructor
Current =
new BackupItemInfo(
ableToReadSubDirectory ? BackupItemInfo.ItemType.Directory : BackupItemInfo.ItemType.UnreadableDirectory,
BaseContainerPath,
nextLevelRelativePath);
break;
}
else
{
continue; // This subdirectory isn't included according to the rules. Loop back and look at the next one.
}
}
else
{
// No more files or subdirectories at this level. Pop up to the next level.
if (!SearchStack.TryPop(out CurrentLevelSearchData))
{
// We're all the way to the top level. We've reached the end.
Current = null;
returnValue = false;
IsStillIterating = false;
}
}
} // end while (isStillIterating)
}
else
{
returnValue = false; // Not reset or still iterating, so we've already moved past the end. Return false.
}
return(returnValue);
} // end MoveNext()
