public static DataContext CreateContext(IDataFileProvider dataFileProvider)
{
// Look for classes that extend DataContext
var types = Assembly.GetExecutingAssembly().GetTypes().Where(t => t.IsSubclassOf(typeof(DataContext)));
foreach (var type in types)
{
// having attribute DataContextAttribute
var dataContextAttribute = (DataContextAttribute)type.GetCustomAttributes(typeof(DataContextAttribute), false).FirstOrDefault();
if (dataContextAttribute != null)
{
DataContext context = (DataContext)Activator.CreateInstance(type);
// Look for plugin specified by the attribute
if (dataFileProvider.GetDataFile(FileMode.Open, dataContextAttribute.PluginFileName).Exists() && dataFileProvider.DataFolderPath.Contains(context.GetGameInstallPath()))
{
// Pass data provider to the context
context.DataFileProvider = dataFileProvider;
return(context);
}
}
}
throw new InvalidDataException("Unable to determine a suitable data context.");
}
/// <summary>
/// Copies a stream into the current data file, optionally only if does not exists and contains different data.
/// </summary>
/// <param name="input">The Stream to copy data from.</param>
/// <param name="updateOnly">If true, file will not be recreated if already exists and contains the same data.</param>
/// <returns>Returns true if file has been created or updated.</returns>
public bool CopyFrom(Stream input, bool updateOnly)
{
if (mode == FileMode.Open)
{
throw new InvalidOperationException("Cannot write into data file retrieved using the FileMode.Open mode.");
}
// Non-data files such as plugin.txt do not have a request path relative to the data folder
// TODO: Do not provide non-data files via DataFileProvider
if (RequestedPath == null)
{
throw new InvalidOperationException("Cannot write into a special data file.");
}
if (updateOnly)
{
// Look if file already exists
// To check whether it needs to be updated
// Retreive new file from the provider with FileMode.Open
var existingFile = provider.GetDataFile(FileMode.Open, RequestedPath);
if (existingFile.Exists())
{
using (var existingStream = existingFile.Open())
{
// If input is not memory stream, create one and copy the data from the input stream into it
MemoryStream memoryStream = input as MemoryStream;
if (memoryStream == null)
{
// Initialize memory stream as big as the existing stream length if imput steam is not seekable
int initialMemoryStreamLength = input.CanSeek ? (int)input.Length : (int)existingStream.Length;
memoryStream = new MemoryStream(initialMemoryStreamLength);
input.CopyTo(memoryStream);
memoryStream.Position = 0;
}
// Compare existing stream with input stream (or memory stream where input stream was copied into)
if (StreamComparer.Compare(existingStream, memoryStream))
{
Log.Fine("Cached file {0} is up to date.", existingFile.FullPath);
return(false);
}
// Reset memeory stream after comparison
memoryStream.Position = 0;
// Use memory stream (where input stream has been copied into) instead of input stream
// when updating existing file
if (input != memoryStream)
{
input = memoryStream;
}
Log.Fine("Cached file {0} exists but is no longer valid and will be updated.", existingFile.FullPath);
}
}
else
{
Log.Fine("File {0} is not cached and will be created.", existingFile.FullPath);
}
}
using (var newStream = Open())
{
input.CopyTo(newStream);
}
return(true);
}
