public void Write(string localFilename, FileData newFile)
{
if (fail) throw new ProcessFailedException(id);
if (freeze)
{
freezed.Enqueue(() => Write(localFilename, newFile));
throw new ProcessFreezedException(id);
}
Console.WriteLine("WRITE " + localFilename
+ " : CONTENTS " + Helper.BytesToString(newFile.Contents)
+ " : VERSION " + newFile.Version);
if (!files.ContainsKey(localFilename))
{
Console.WriteLine("CREATE FILE " + localFilename);
files[localFilename] = newFile;
weights[localFilename] = new Weight();
}
else
{
files[localFilename] = FileData.Latest(files[localFilename], newFile);
}
weights[localFilename].Writes++;
Console.WriteLine("STORED = " + files[localFilename].Version);
}
public FileData Read(string localFilename)
{
if (fail) throw new ProcessFailedException(id);
if (freeze)
{
freezed.Enqueue(() => Read(localFilename));
throw new ProcessFreezedException(id);
}
Console.WriteLine("READ " + localFilename);
if (!files.ContainsKey(localFilename))
{
Console.WriteLine("CREATE FILE " + localFilename);
files[localFilename] = new FileData();
weights[localFilename] = new Weight();
}
weights[localFilename].Reads++;
return files[localFilename];
}
/**
* IDataServerToClient Methods
*/
public FileVersion Version(string localFilename)
{
if (fail) throw new ProcessFailedException(id);
if (freeze)
{
freezed.Enqueue(() => Version(localFilename));
throw new ProcessFreezedException(id);
}
Console.WriteLine("VERSION " + localFilename);
if (!files.ContainsKey(localFilename))
{
Console.WriteLine("CREATE FILE " + localFilename);
files[localFilename] = new FileData();
weights[localFilename] = new Weight();
}
return files[localFilename].Version;
}
public void MigrationWrite(string localFilename, FileData newFile, Weight weight)
{
if (fail) throw new ProcessFailedException(id);
if (freeze)
{
freezed.Enqueue(() => MigrationWrite(localFilename, newFile, weight));
throw new ProcessFreezedException(id);
}
Console.WriteLine("MIGRATION WRITE " + localFilename);
files[localFilename] = newFile;
weights[localFilename] = weight;
}
public void Write(int fileRegisterIndex, byte[] contents)
{
Console.WriteLine("WRITE FILE = " + fileRegisterIndex);
try
{
// forces to get always the most recent file
FileVersion latest = ReadVersion(fileRegisterIndex, Helper.Semantics.MONOTONIC).Version;
latest.Increment(Client.id);
FileData fileData = new FileData(latest, contents);
string filename = fileRegister.FilenameAt(fileRegisterIndex);
FileMetadata fileMetadata = fileRegister.FileMetadataAt(fileRegisterIndex);
// data server id / bool write
ConcurrentDictionary<string, bool> writes = new ConcurrentDictionary<string, bool>();
int requests = 0;
bool quorumReached = false;
//QUORUM
while (true)
{
// voting
WriteQuorum quorum = new WriteQuorum(fileMetadata.WriteQuorum);
foreach (var entry in writes)
{
bool vote = entry.Value;
quorum.AddVote(vote);
if (quorum.CheckQuorum())
{
quorumReached = true;
break;
}
}
// found the quorum file
if (quorumReached) break;
// if there are still pending requests
// dont create new ones
if (requests > 0) continue;
// if all the votes arrived at the quorum
// stops when all requests are counted (requests = 0)
if (quorum.Count == (requests + quorum.Count))
{
// get possible new fileMetadata locations
// possible optimization
// check if there are no dataa servers
fileMetadata = OpenFileMetadata(filename);
// broadcast to all dataServers that have that file
foreach (var entry in fileMetadata.Locations)
{
string id = entry.Key;
string location = entry.Value;
string localFilename = fileMetadata.LocalFilenames[id];
// increment right away so it doesn't request untill its decremented
Interlocked.Increment(ref requests);
Thread request = new Thread(() =>
{
IDataServerToClient dataServer = (IDataServerToClient)Activator.GetObject(
typeof(IDataServerToClient),
location);
bool vote = false;
try
{
dataServer.Write(localFilename, fileData);
vote = true;
}
catch (ProcessFailedException) { }
catch (ProcessFreezedException) { }
finally
{
writes[id] = vote;
Interlocked.Decrement(ref requests);
}
});
request.Start();
}
}
}
// update file registers
fileRegister.SetFileDataAt(fileRegisterIndex, fileData);
}
catch (FileDoesNotExistException e)
{
Console.WriteLine(e.Message);
return;
}
}
public void SetFileDataAt(int index, FileData newFileData)
{
if (!filenames.ContainsKey(index))
throw new Exception("Index does not exist");
infos[filenames[index]].fileData = newFileData;
}
public static FileData Latest(FileData f1, FileData f2)
{
return (FileVersion.MostRecent(f1.version, f2.version) >= 0) ? f1 : f2;
}
public static FileData Latest(FileData f1, FileData f2)
{
return((FileVersion.MostRecent(f1.version, f2.version) >= 0) ? f1 : f2);
}
