int IMessageController.SendToPeer(SendMemoryToPeer message)
{
if (this.IsAlive)
{
return(CastTargetController.SendToPeer(message));
}
else
{
return(0);
}
}
/// <summary>
/// Closes the TCP connection as soon as possible.
/// </summary>
internal void Close(bool disposing)
{
// TODO: need to create an asymmetric close handshake
SendMemoryToPeer endMsg = new SendMemoryToPeer(CLOSE_MESSAGE, new List<int>() { this.remote_uid });
ResponseCode(endMsg.MemBuffer, CLOSE_MESSAGE, GetListOfThisLocalID(), 0, 0, 200);
SendToRemoteClient(endMsg);
if (!disposing)
{
// spin wait
while (this.state != ConnectionState.Closed)
{
Thread.Sleep(P2PDictionary.SLEEP_WAIT_TO_CLOSE);
}
}
}
private void HandleReadDelete(string contentLocation,string eTag, List<int> senders, List<int> responsePath )
{
// handle proxy messages
if (contentLocation.StartsWith(PROXY_PREFIX + "/"))
{
contentLocation = contentLocation.Substring(PROXYPREFIX_REMOVE);
if (!keysToListen.IsSubscribed(contentLocation))
{
keysToListen.AddSubscription(contentLocation, SubscriptionInitiator.AutoProxyKey);
}
}
// read
ResponseAction status = ReadDelete(contentLocation, eTag, new List<int>(senders));
if (status == ResponseAction.ForwardToAll)
{
//conflict happened in data somewhere
// return new data to sender
senders.Clear();
}
if (status != ResponseAction.DoNotForward)
{
// send a notification of deleted content immediately
DataEntry entry = P2PDictionary.GetEntry(this.data, this.dataLock, contentLocation);
System.Diagnostics.Debug.Assert(entry != null);
// add to wire to send out
senders.Add(this.local_uid);// add my sender to the packet
SendBroadcastMemory sendMsg = new SendBroadcastMemory(entry.key, senders);
WriteMethodDeleted(sendMsg.MemBuffer, contentLocation, senders, responsePath, entry.lastOwnerID, entry.lastOwnerRevision);
controller.BroadcastToWire(sendMsg);
}
if (responsePath != null)
{
// well, i still have to send out this message because there is a path requested to follow
DataEntry entry = P2PDictionary.GetEntry(this.data, this.dataLock, contentLocation);
System.Diagnostics.Debug.Assert(entry != null);
SendMemoryToPeer sendMsg = new SendMemoryToPeer(entry.key, responsePath);
senders.Add(this.local_uid);// add my sender to the packet
WriteMethodDeleted(sendMsg.MemBuffer, PROXY_PREFIX + contentLocation, senders, responsePath, entry.lastOwnerID, entry.lastOwnerRevision);
}
}
/// <summary>
/// Creates a message with LocalUID as the sender list
/// </summary>
/// <param name="proxyKey">The resource name to return, prefixed with proxy/* for a proxy response.</param>
/// <param name="key">Any dictionary element in the data/* namespace, or the data dictionary itself.</param>
/// <returns></returns>
public SendMemoryToPeer CreateResponseMessage(string key, string proxyKey, List<int> senderPath, List<int> includeList, List<int> proxyResponsePath)
{
SendMemoryToPeer msg = new SendMemoryToPeer(proxyKey, includeList);
if (key == DATA_NAMESPACE)
{
ResponseDictionary(GET, msg.MemBuffer, senderPath, proxyResponsePath, false);
}
else
{
DataEntry entry = P2PDictionary.GetEntry( this.data, this.dataLock, key);
System.Diagnostics.Debug.Assert(entry != null);
if (!entry.subscribed)
{
throw new NotImplementedException();
}
Response(GET, proxyKey, senderPath, proxyResponsePath, entry, msg.MemBuffer, false);
}
return msg;
}
/// <summary>
/// Fills bufferedOutput with the response, or asks the controller to pull the contentLocation from another peer.
/// </summary>
/// <param name="contentLocation">A location prefixed with /proxy.</param>
/// <param name="requestPath">Path that the request should follow.</param>
/// <returns>A new object to reply to the sender</returns>
private SendMemoryToPeer RespondOrForwardProxy(string contentLocation, List<int> senderList)
{
// first 6 characters of /proxy are removed
bool proxyPart = contentLocation.StartsWith(PROXY_PREFIX + "/");
if (proxyPart == false)
throw new NotSupportedException("RespondOrForwardProxy no proxy part");
string key = contentLocation.Substring(PROXYPREFIX_REMOVE);
List<int> hintPath = null;
// cannnot proxy request the whole dictionary
if (key == DATA_NAMESPACE)
throw new NotSupportedException("RespondOrForwardProxy DATA_NAMESPACE");
bool responded = false;
DataEntry e = P2PDictionary.GetEntry( this.data, this.dataLock, key);
if (e != null)
{
WriteDebug(this.local_uid + " following proxy path, found content for " + key);
lock (e)
{
if (e.subscribed && !DataMissing.IsSingleton(e.value))
{
responded = true;
}
}
if (responded)
{
// change the return path of the response message
List<int> followList = new List<int>(senderList);
followList.Remove(this.local_uid);
SendMemoryToPeer sendMsg = CreateResponseMessage(key, PROXY_PREFIX + key, GetListOfThisLocalID(), followList, followList);
return sendMsg;
}
hintPath = e.senderPath;
}
if (!responded)
{
// fix the requestPath with the hintPath if there is no requestPath,
// or if the requestPath is now at the current peer
if (hintPath == null || hintPath.Count == 0)
{
WriteDebug(this.local_uid + " forwarding request dropped " + key);
}
else
{
// since the path contains all the nodes to contact in order,
// we don't have to broadcast a request. Instead, we just specify
// the path to the next peer and it will get to the destination.
senderList = new List<int>(senderList);
senderList.Add(this.local_uid);
WriteDebug(this.local_uid + " following proxy path " + key + " to " + GetStringOf(hintPath));
SendMemoryToPeer sendMsg = new SendMemoryToPeer(PROXY_PREFIX + key, hintPath);
ResponseFollowProxy(sendMsg.MemBuffer, PROXY_PREFIX + key, senderList);
return sendMsg;
}
}
return null;
}
/// <summary>
/// TODO: add in some code to reduce round-trips to simple data types
/// </summary>
/// <param name="reader">File to read</param>
/// <param name="sentFromList">Sent from list</param>
/// <param name="getEntriesFromSender">This function fills in a list of entries that need to be requested from the sender</param>
/// <param name="addEntriesToSender">These are entries that the sender does not know about</param>
/// <seealso cref="ReadHeadStub"/>
private void ReadDictionaryTextFile(StreamReader reader, List<int> sentFromList, List<DataHeader> getEntriesFromSender, List<SendMemoryToPeer> addEntriesToSender)
{
// 0 - key name
// 1 - owner
// 2 - revision
// 3 - rw flag
// 4 - MIME type
// WriteDebug(this.local_uid + " ReadDictionaryTextFile");
string nsLine = reader.ReadLine();
string[] nsLineParts = nsLine.Split('\t');
System.Diagnostics.Debug.Assert(nsLineParts[0] == DATA_NAMESPACE + "/");
// if the owner of the dictionary is the same as myself, skip reading the changes
if (nsLineParts[1] == this.local_uid.ToString())
{
throw new NotSupportedException("ReadDictionaryTextFile cannot read itself");// i want to see if this actually can happen (only when multiple connections happen on the same server)
}
int itemCount = int.Parse(nsLineParts[4]); // count of all the items in the dictionary
List<DataEntry> entriesCovered = new List<DataEntry>(itemCount + this.data.Count);
for (int i = 0; i < itemCount; i++)
{
nsLine = reader.ReadLine();
nsLineParts = nsLine.Split('\t');
//WriteDebug(nsLine);
DataHeader getEntry = null;
SendMemoryToPeer addEntryToSender = null;
ETag tag = new ETag(int.Parse(nsLineParts[1]), int.Parse(nsLineParts[2]));
// this entry is used only to call ReadMimeSimpleData
DataEntry fakeEntry = new DataEntry("/fake", tag, new List<int>(0));
fakeEntry.ReadMimeSimpleData(nsLineParts[4]);
dataLock.EnterReadLock();
try
{
if (this.data.ContainsKey(nsLineParts[0]))
{
entriesCovered.Add(this.data[nsLineParts[0]]);
}
}
finally { dataLock.ExitReadLock(); }
// the dictionary does not report the current sender so let's tack it on
List<int> listOfSenders = new List<int>(GetArrayOf(nsLineParts[5]));
if (!listOfSenders.Contains(this.remote_uid))
listOfSenders.Add(this.remote_uid);
ResponseAction action = ReadDataStub(nsLineParts[0], fakeEntry.GetMime(), nsLineParts[1] + "." + nsLineParts[2], new List<int>( listOfSenders), out getEntry, out addEntryToSender);
if (getEntry != null)
{
getEntriesFromSender.Add(getEntry);
}
if (addEntryToSender != null)
{
addEntriesToSender.Add(addEntryToSender);
}
if (action == ResponseAction.ForwardToAll)
{
listOfSenders.Clear();
}
if (action != ResponseAction.DoNotForward)
{
DataEntry get = P2PDictionary.GetEntry( this.data, this.dataLock, nsLineParts[0]);
System.Diagnostics.Debug.Assert(get != null);
listOfSenders.Add(this.local_uid);
SendBroadcastMemory msg = new SendBroadcastMemory(get.key , listOfSenders);
WriteMethodPush(get.key, listOfSenders, null, 0, get.GetMime(), get.GetETag(), get.IsEmpty, false, msg.MemBuffer);
this.controller.BroadcastToWire(msg);
}
}
// now check to see which dictionary entries that the sender does not have; i'll send my entries to the caller
this.dataLock.EnterWriteLock();
try
{
foreach (KeyValuePair<string, DataEntry> senderDoesNotHave in this.data.SkipWhile(x => entriesCovered.Contains(x.Value)))
{
DataEntry get = senderDoesNotHave.Value;
// i know about something that the sender does not know
SendMemoryToPeer mem = new SendMemoryToPeer(get.key, sentFromList);
WriteMethodPush(get.key, GetListOfThisLocalID(), null, 0, get.GetMime(), get.GetETag(), get.IsEmpty, false, mem.MemBuffer);
addEntriesToSender.Add(mem);
}
}
finally { this.dataLock.ExitWriteLock();}
}
/// <summary>
/// Reads data using only header information. Can be used by ReadDictionary
/// so it handles deleted content too.
/// </summary>
/// <param name="contentLocation">Location of the data item without /proxy</param>
/// <param name="contentType">GetMime()</param>
/// <param name="eTag">Version number</param>
/// <param name="addEntryToSender">These are entries that the sender does not know about</param>
/// <param name="getEntryFromSender">This function fills in a list of entries that need to be requested from the sender</param>
private ResponseAction ReadDataStub(string contentLocation, string contentType, string eTag,
List<int> sentFromList, out DataHeader getEntryFromSender, out SendMemoryToPeer addEntryToSender)
{
ResponseAction success = ResponseAction.DoNotForward;
ETag tag = ReadETag(eTag);
DataEntry get = null;
getEntryFromSender = null;
addEntryToSender = null;
// create a stub of the item
DataEntry create = new DataEntry(contentLocation, tag, sentFromList);
create.subscribed = keysToListen.IsSubscribed(contentLocation);
create.SetMime(contentType);
// manually erase the value (TODO, don't erase the value)
// always default to singleton because we assume that a GET is required to complete the request
if (create.type != Data.ValueType.Removed)
create.value = DataMissing.Singleton;
this.dataLock.EnterUpgradeableReadLock();
try
{
if (this.data.ContainsKey(contentLocation))
{
// update the version number of the stub
get = this.data[contentLocation];
}
else
{
this.dataLock.EnterWriteLock();
try
{
this.data.Add(contentLocation, create);
}
finally { this.dataLock.ExitWriteLock(); }
if (create.subscribed && DataMissing.IsSingleton(create.value))
{
// we'll have to wait for the data to arrive on the wire
// actually get the data
getEntryFromSender = new DataHeader(contentLocation, tag, sentFromList);
success = ResponseAction.DoNotForward;
}
else
{
success = ResponseAction.ForwardToSuccessor;
}
}
}
finally
{
this.dataLock.ExitUpgradeableReadLock();
}
if (get != null)
{
lock (get)
{
if (create.subscribed)
{
ETagCompare compareResult = ETag.CompareETags(tag, get.GetETag());
if (compareResult == ETagCompare.FirstIsNewer ||
compareResult == ETagCompare.Same || compareResult == ETagCompare.Conflict)
{
getEntryFromSender = new DataHeader(create.key, create.GetETag(), sentFromList);
success = ResponseAction.DoNotForward;
}
else //if (compareResult == ETagCompare.SecondIsNewer )
{
// i know about something newer than the sender, tell the sender
//SendMemoryToPeer mem = new SendMemoryToPeer(get.key,sentFromList);
//ResponseHeadStub(HEAD, get.key, GetListOfThisLocalID(), 0, get.GetMime(), get.GetETag(), get.IsEmpty, mem.MemBuffer, false);
//addEntryToSender = mem;
// well, predecessor already been handled above, so we only need to tell
// the others
success = ResponseAction.ForwardToAll;
}
}
else
{
// not subscribed
// just record the fact that there is newer data on the wire; cannot resolve conflicts without being a subscriber
ETagCompare compareResult = ETag.CompareETags(create.GetETag(), get.GetETag());
if (compareResult == ETagCompare.FirstIsNewer || compareResult == ETagCompare.Same || compareResult == ETagCompare.Conflict)
{
get.lastOwnerID = create.lastOwnerID;
get.lastOwnerRevision = create.lastOwnerRevision;
get.value = DataMissing.Singleton;
if (compareResult != ETagCompare.Same)
{
get.senderPath = create.senderPath;
success = ResponseAction.ForwardToSuccessor;
}
else
success = ResponseAction.DoNotForward;
}
else // if (compareResult == ETagCompare.SecondIsNewer )
{
//// i know about something newer than the sender
//SendMemoryToPeer mem = new SendMemoryToPeer(get.key,sentFromList);
//ResponseHeadStub(HEAD, get.key, GetListOfThisLocalID(), 0, get.GetMime(), get.GetETag(), get.IsEmpty, mem.MemBuffer, false);
//addEntryToSender = mem;
// tell the others too (already told predecessor above)
success = ResponseAction.ForwardToAll;
}
}
}
}
return success;
}
int IMessageController.SendToPeer(SendMemoryToPeer message)
{
if (this.IsAlive)
return CastTargetController.SendToPeer(message);
else
return 0;
}
