/// <summary>
/// Loads previous versions stored from the specified file path.
/// </summary>
/// <param name="filePath">The file path.</param>
/// <returns>FileVersionTracker.</returns>
public static FileVersionTracker Load(string filePath)
{
// Try to compact it before using it
FileVersionStorage.Compact(filePath);
bool isFirstPass = true;
while (true)
{
FileStream fileStream = null;
// Try to open the file, if we get an exception, this might be due only because someone is locking the file to
// save it while we are trying to open it
const int RetryOpenFileStream = 20;
var random = new Random();
for (int i = 0; i < RetryOpenFileStream; i++)
{
try
{
fileStream = new FileStream(filePath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
break;
}
catch (Exception)
{
if ((i + 1) == RetryOpenFileStream)
{
throw;
}
Thread.Sleep(50 + random.Next(100));
}
}
var tracker = new FileVersionTracker(fileStream);
try
{
tracker.storage.LoadNewValues();
return(tracker);
}
catch (Exception)
{
// If an exception occurred, we are going to try to recover from it by reseting it.
// reset file length to 0
fileStream.SetLength(0);
tracker.Dispose();
if (!isFirstPass)
{
throw;
}
}
isFirstPass = false;
}
}
/// <summary>
/// Compacts the specified storage path.
/// </summary>
/// <param name="storagePath">The storage path.</param>
/// <returns><c>true</c> if the storage path was successfully compacted, <c>false</c> otherwise.</returns>
public static bool Compact(string storagePath)
{
FileStream fileStreamExclusive;
try
{
fileStreamExclusive = new FileStream(storagePath, FileMode.Open, FileAccess.ReadWrite, FileShare.None);
}
catch (Exception)
{
return(false);
}
try
{
using (var localTracker = new FileVersionStorage(fileStreamExclusive)
{
UseTransaction = true, AutoLoadNewValues = false
})
{
localTracker.LoadNewValues();
var latestVersion = new Dictionary <string, KeyValuePair <FileVersionKey, ObjectId> >(StringComparer.OrdinalIgnoreCase);
foreach (var keyValue in localTracker.GetValues())
{
var filePath = keyValue.Key.Path;
KeyValuePair <FileVersionKey, ObjectId> previousKeyValue;
if (!latestVersion.TryGetValue(filePath, out previousKeyValue) || keyValue.Key.LastModifiedDate > previousKeyValue.Key.LastModifiedDate)
{
latestVersion[filePath] = keyValue;
}
}
localTracker.Reset();
localTracker.AddValues(latestVersion.Values);
localTracker.Save();
}
}
catch (Exception)
{
return(false);
}
return(true);
}
/// <summary>
/// Initializes a new instance of the <see cref="FileVersionTracker"/> class.
/// </summary>
/// <param name="stream">The stream.</param>
public FileVersionTracker(Stream stream)
{
storage = new FileVersionStorage(stream);
locks = new Dictionary <FileVersionKey, object>();
}