/// <summary>
/// Initializes a new instance of the <see cref="FileEnumerator"/> class.
/// </summary>
/// <param name="path">The directory to search.</param>
/// <param name="fileExtension">The file extension to search for.</param>
/// <param name="searchOption">
/// One of the <see cref="SearchOption"/> values that specifies whether the search operation should include only the current directory or should include all subdirectories.
/// </param>
/// <param name="dereferenceLinks">If set to <c>true</c> search the target of shortcuts.</param>
/// <exception cref="ArgumentNullException">
/// <paramref name="path"/> in null.
/// -or-
/// <paramref name="fileExtension"/> is null.
/// </exception>
/// <exception cref="ArgumentException"><paramref name="path"/> is a 0 length string, or contains only white-space, or contains one or more invalid characters as defined by <see cref="Path.GetInvalidPathChars"/>.</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="searchOption"/> is not a valid <see cref="SearchOption"/> value.</exception>
/// <exception cref="DirectoryNotFoundException">The directory specified by <paramref name="path"/> does not exist.</exception>
/// <exception cref="IOException"><paramref name="path"/> is a file.</exception>
/// <exception cref="PathTooLongException">The specified path, file name, or combined exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters and file names must be less than 260 characters.</exception>
/// <exception cref="UnauthorizedAccessException">The caller does not have the required permission.</exception>
/// <exception cref="SecurityException">The caller does not have the required permission.</exception>
public FileEnumerator(string path, string fileExtension, SearchOption searchOption, bool dereferenceLinks)
{
if (path == null)
{
throw new ArgumentNullException(nameof(path));
}
if (fileExtension == null)
{
throw new ArgumentNullException(nameof(fileExtension));
}
if (searchOption < SearchOption.TopDirectoryOnly || searchOption > SearchOption.AllDirectories)
{
throw new ArgumentOutOfRangeException(nameof(searchOption));
}
string fullPath = Path.GetFullPath(path);
string demandPath = GetPermissionPath(fullPath, false);
new FileIOPermission(FileIOPermissionAccess.PathDiscovery, demandPath).Demand();
needsPathDiscoveryDemand = false;
searchData = new SearchData(fullPath);
this.fileExtension = fileExtension;
this.searchOption = searchOption;
searchDirectories = new Queue <SearchData>();
if (dereferenceLinks)
{
shellLink = new ShellLink();
this.dereferenceLinks = true;
}
else
{
shellLink = null;
this.dereferenceLinks = false;
}
shellLinkTarget = null;
visitedDirectories = new HashSet <DirectoryIdentifier>();
if (OS.IsWindows7OrLater)
{
// Suppress the querying of short filenames and use a larger buffer on Windows 7 and later.
infoLevel = NativeEnums.FindExInfoLevel.Basic;
additionalFlags = NativeEnums.FindExAdditionalFlags.LargeFetch;
}
else
{
infoLevel = NativeEnums.FindExInfoLevel.Standard;
additionalFlags = NativeEnums.FindExAdditionalFlags.None;
}
oldErrorMode = SetErrorModeWrapper(NativeConstants.SEM_FAILCRITICALERRORS);
state = -1;
current = null;
disposed = false;
Init();
}
/// <summary>
/// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
/// </summary>
public void Dispose()
{
if (!disposed)
{
disposed = true;
if (handle != null)
{
handle.Dispose();
handle = null;
}
if (shellLink != null)
{
shellLink.Dispose();
shellLink = null;
}
current = null;
state = -1;
SetErrorModeWrapper(oldErrorMode);
}
}