/**
<summary>Begins a new transfer state to the neighbor connected via con.
</summary>
<param name="con">The connection to the neigbhor we will be transferring
data to.</param>
<param name="ts">The table server we're providing the transfer for. C#
does not allow sub-class objects to have access to their parent objects
member variables, so we pass it in like this.</param>
<remarks>
Step 1:
Get all the keys between me and my new neighbor.
Step 2:
Get all values for those keys, we copy so that we don't worry about
changes to the dht during this interaction. This is only a pointer
copy and since we let the OS deal with removing the contents of an
entry, we don't need to make copies of the actual entry.
Step 3:
Generate another list of keys of up to max parallel transfers and begin
transferring, that way we do not need to lock access to the entry
enumerator until non-constructor puts.
Step 4:
End constructor, results from puts, cause the next entry to be sent.
*/
public TransferState(Brunet.Connections.Connection con, TableServer ts) {
this._ts = ts;
this._con = con;
// Get all keys between me and my new neighbor
LinkedList<MemBlock> keys;
lock(_ts._sync) {
keys = _ts._data.GetKeysBetween((AHAddress) _ts._node.Address,
(AHAddress) _con.Address);
}
if(Dht.DhtLog.Enabled) {
ProtocolLog.Write(Dht.DhtLog, String.Format(
"Starting transfer from {0} to {1}",
_ts._node.Address, _con.Address));
}
int total_entries = 0;
/* Get all values for those keys, we copy so that we don't worry about
* changes to the dht during this interaction. This is only a pointer
* copy and since we let the OS deal with removing the contents of an
* entry, we don't need to make copies of the actual entry.
*/
foreach(MemBlock key in keys) {
Entry[] entries;
lock(_ts._sync) {
LinkedList<Entry> llentries = _ts._data.GetEntries(key);
if(llentries == null) {
continue;
}
entries = new Entry[llentries.Count];
total_entries += llentries.Count;
llentries.CopyTo(entries, 0);
}
key_entries.AddLast(entries);
}
if(Dht.DhtLog.Enabled) {
ProtocolLog.Write(Dht.DhtLog, String.Format(
"Total keys: {0}, total entries: {1}.",
key_entries.Count, total_entries));
}
_entry_enumerator = GetEntryEnumerator();
/* Here we generate another list of keys that we would like to
* this is done here, so that we can lock up the _entry_enumerator
* only during this stage and not during the RpcManager.Invoke
*/
LinkedList<Entry> local_entries = new LinkedList<Entry>();
for(int i = 0; i < MAX_PARALLEL_TRANSFERS && _entry_enumerator.MoveNext(); i++) {
local_entries.AddLast((Entry) _entry_enumerator.Current);
}
foreach(Entry ent in local_entries) {
Channel queue = new Channel();
queue.CloseAfterEnqueue();
queue.CloseEvent += this.NextTransfer;
int ttl = (int) (ent.EndTime - DateTime.UtcNow).TotalSeconds;
try {
_ts._rpc.Invoke(_con.Edge, queue, "dht.PutHandler", ent.Key, ent.Value, ttl, false);
}
catch {
if(_con.Edge.IsClosed) {
_interrupted = true;
Done();
break;
}
}
}
}
/// <summary>This is a RpcDhtProxy rpc call entry, which can be called using "RpcDhtProxy.Register"
/// Register the entry to Entry. If the key,value pair does not
/// exist in _entries, it creates the pair in the list. Otherwise, it updates the ttl.
/// After inserting the entry, this module try to register the key, value pair to neighbor node.</summary>
/// <param name="key">dht entry key to insert</param>
/// <param name="value">dht entry value to insert</param>
/// <param name="ttl">dht entry ttl to insert</param>
public bool Register(MemBlock key, MemBlock value, int ttl)
{
Entry entry = null;
lock(_sync) {
Dictionary<MemBlock, Entry> key_entries = null;
if(!_entries.TryGetValue(key, out key_entries)) {
key_entries = new Dictionary<MemBlock, Entry>();
_entries[key] = key_entries;
}
if(key_entries.ContainsKey(value)) {
key_entries[value].Timer.Stop();
}
entry = new Entry(key, value, ttl);
key_entries[value] = entry;
}
if(entry != null) {
entry.Timer = new SimpleTimer(EntryCallback, entry, 0, RETRY_TIMEOUT);
entry.Timer.Start();
}
return true;
}
/**
<summary>Attempts to store the key:value pair into this server.</summary>
<remarks>First the dht deletes any expired entries stored at the key,
second it retrieves the entries from the data store. If it is empty it
creates a new entry and returns. Otherwise, it looks for the value in
the list and updates the lease time. If there is no entry for that
key:value pair it either adds it in the case of a put or throws an
exception if it is a create.</remarks>
<param name="key">The index to store the data at.</param>
<param name="value">Data to store at the key.</param>
<param name="ttl">Dht lease time in seconds</param>
<param name="unique">True if this should perform a create, false otherwise.
</param>
<returns>True on success, thrown exception on failure</returns>
<exception cref="Exception">Data is too large, unresolved remote issues,
or the create is no successful</exception>
*/
public bool PutHandler(MemBlock key, MemBlock value, int ttl, bool unique) {
DateTime create_time = DateTime.UtcNow;
DateTime end_time = create_time.AddSeconds(ttl);
lock(_sync) {
_data.DeleteExpired(key);
LinkedList<Entry> data = _data.GetEntries(key);
if(data != null) {
foreach(Entry ent in data) {
if(ent.Value.Equals(value)) {
if(end_time > ent.EndTime) {
_data.UpdateEntry(ent.Key, ent.Value, end_time);
}
return true;
}
}
// If this is a create we didn't find an previous entry, so failure, else add it
if(unique) {
throw new Exception("ENTRY_ALREADY_EXISTS");
}
}
// This is either a new key or a new value (put only)
Entry e = new Entry(key, value, create_time, end_time);
_data.AddEntry(e);
} // end of lock
return true;
}
/**
<summary>Retrieves data from the Dht.</summary>
<remarks>First old entries for the key are deleted from the dht, second a
look up is performed, and finally using the token a range of data is
selectively returned.</remarks>
<param name="key">The index used to look up.</summary>
<param name="token">Contains the data necessary to do follow up look ups
if all the data stored in a key is to big for MAX_BYTES.</param>
<returns>IList of hashtables containing the results. Compatible with
DhtGetResult.</returns>
*/
public IList Get(MemBlock key, byte[] token) {
int seen_start_idx = 0;
int seen_end_idx = 0;
if( token != null ) {
using(MemoryStream ms = new MemoryStream(token)) {
int[] bounds = (int[])AdrConverter.Deserialize(ms);
seen_start_idx = bounds[0];
seen_end_idx = bounds[1];
seen_start_idx = seen_end_idx + 1;
}
}
int consumed_bytes = 0;
Entry[] data = null;
lock(_sync ) {
_data.DeleteExpired(key);
LinkedList<Entry> ll_data = _data.GetEntries(key);
// Keys exist!
if( ll_data != null ) {
data = new Entry[ll_data.Count];
ll_data.CopyTo(data, 0);
}
}
ArrayList result = null;
if(data != null) {
result = new ArrayList();
ArrayList values = new ArrayList();
int remaining_items = 0;
byte[] next_token = null;
seen_end_idx = data.Length - 1;
for(int i = seen_start_idx; i < data.Length; i++) {
Entry e = (Entry) data[i];
if(e.Value.Length + consumed_bytes <= MAX_BYTES) {
int age = (int) (DateTime.UtcNow - e.CreateTime).TotalSeconds;
int ttl = (int) (e.EndTime - DateTime.UtcNow).TotalSeconds;
consumed_bytes += e.Value.Length;
Hashtable item = new Hashtable();
item["age"] = age;
item["value"] = (byte[])e.Value;
item["ttl"] = ttl;
values.Add(item);
}
else {
seen_end_idx = i - 1;
break;
}
}
remaining_items = data.Length - (seen_end_idx + 1);
//Token creation
int[] new_bounds = new int[2];
new_bounds[0] = seen_start_idx;
new_bounds[1] = seen_end_idx;
using(MemoryStream ms = new System.IO.MemoryStream()) {
AdrConverter.Serialize(new_bounds, ms);
next_token = ms.ToArray();
}
result.Add(values);
result.Add(remaining_items);
result.Add(next_token);
}
return result;
}
public void Test1() {
RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
TableServerData tsd = new TableServerData("0");
Entry[] not_expired = new Entry[12];
Entry[] to_expire = new Entry[12];
DateTime now = DateTime.UtcNow;
DateTime live = now.AddSeconds(120);
DateTime expire = now.AddSeconds(5);
for(int i = 0; i < 4; i++) {
byte[] key = new byte[20];
rng.GetBytes(key);
for(int j = 0; j < 3; j++) {
byte[] value = new byte[20];
rng.GetBytes(value);
Entry ent = new Entry(key, value, now, expire);
to_expire[i * 3 + j] = ent;
tsd.AddEntry(ent);
value = new byte[20];
rng.GetBytes(value);
ent = new Entry(key, value, now, live);
not_expired[i * 3 + j] = ent;
tsd.AddEntry(ent);
Assert.IsFalse(not_expired[i * 3 + j].Equals(to_expire[i * 3 + j]),
String.Format("{0}: not_expired == to_expire.", i * 3 + j));
}
}
for(int i = 0; i < 4; i++) {
LinkedList<Entry> entries = tsd.GetEntries(not_expired[i * 3].Key);
for(int j = 0; j < 3; j++) {
Assert.IsTrue(entries.Contains(not_expired[i * 3 + j]), "step 0: not_expired " + (i * 3 + j));
Assert.IsTrue(entries.Contains(to_expire[i * 3 + j]), "step 0: to_expire " + (i * 3 + j));
}
}
for(int i = 0; i < 4; i++) {
for(int j = 0; j < 3; j++) {
int pos = i * 3 + j;
if(pos % 2 == 0) {
Entry ent = not_expired[pos];
tsd.UpdateEntry(ent.Key, ent.Value, now.AddSeconds(160));
}
}
}
Entry entry = to_expire[11];
tsd.UpdateEntry(entry.Key, entry.Value, now.AddSeconds(160));
for(int i = 0; i < 4; i++) {
LinkedList<Entry> entries = tsd.GetEntries(not_expired[i * 3].Key);
for(int j = 0; j < 3; j++) {
Assert.IsTrue(entries.Contains(not_expired[i * 3 + j]), "step 1: not_expired " + (i * 3 + j));
Assert.IsTrue(entries.Contains(to_expire[i * 3 + j]), "step 1: to_expire " + (i * 3 + j));
}
}
while(DateTime.UtcNow < expire.AddSeconds(1)) {
for(int i = 0; i < 50000000; i++) {
int k = i % 5;
k += 6;
}
}
for(int i = 0; i < 3; i++) {
LinkedList<Entry> entries = tsd.GetEntries(not_expired[i * 3].Key);
for(int j = 0; j < 3; j++) {
Assert.IsTrue(entries.Contains(not_expired[i * 3 + j]), "step 2: not_expired " + (i * 3 + j));
Assert.IsFalse(entries.Contains(to_expire[i * 3 + j]), "step 2: to_expire " + (i * 3 + j));
}
}
Assert.AreEqual(13, tsd.Count, "Entries we didn't check are removed by CheckEntries.");
}
public void Test0() {
RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
TableServerData tsd = new TableServerData("0");
byte[] key = new byte[20];
rng.GetBytes(key);
DateTime now = DateTime.UtcNow;
Entry ent = new Entry(key, key, now, now.AddSeconds(100));
tsd.AddEntry(ent);
LinkedList<Entry> entries = tsd.GetEntries(key);
Assert.AreEqual(1, entries.Count, "Count after add");
Assert.AreEqual(ent, entries.First.Value, "Entries are equal");
tsd.UpdateEntry(ent.Key, ent.Value, now.AddSeconds(200));
entries = tsd.GetEntries(key);
Assert.AreEqual(1, entries.Count, "Count after update");
Assert.AreEqual(ent, entries.First.Value, "Entries are equal");
tsd.RemoveEntry(ent.Key, ent.Value);
entries = tsd.GetEntries(key);
Assert.AreEqual(tsd.Count, 0, "Count after remove");
Assert.AreEqual(null, entries, "Entry after remove");
}
/**
<summary>Disk caching is unsupported at this time.</summary>
*/
/* When we have a cache miss, we should try to load the data from disk,
* if we are successful, we should also delete that file from the disk
*/
public void CacheMiss(Object o, EventArgs args) {
Brunet.Collections.Cache.MissArgs margs = (Brunet.Collections.Cache.MissArgs) args;
MemBlock key = (MemBlock) margs.Key;
string path = GeneratePath(key);
if(File.Exists(path)) {
using (FileStream fs = File.Open(path, FileMode.Open)) {
ArrayList ht_entries = (ArrayList) AdrConverter.Deserialize(fs);
Entry[] entries = new Entry[ht_entries.Count];
int index = 0;
foreach(Hashtable entry in ht_entries) {
entries[index++] = (Entry) entry;
}
_data[key] = new LinkedList<Entry>(entries);
}
File.Delete(path);
}
}
/**
<summary>Disk caching is unsupported at this time.</summary>
*/
/* When we have a cache eviction, we must write it to disk, we take
* each entry, convert it explicitly into a hashtable, and then use adr
* to create a stream and write it to disk
*/
public void CacheEviction(Object o, EventArgs args) {
Brunet.Collections.Cache.EvictionArgs eargs = (Brunet.Collections.Cache.EvictionArgs) args;
MemBlock key = (MemBlock) eargs.Key;
if(Dht.DhtLog.Enabled) {
ProtocolLog.Write(Dht.DhtLog, String.Format(
"Evicted out of cache {0}, entries in dht {1}, entries in cache {2}",
(new BigInteger(key)).ToString(16), Count, _data.Count));
}
if(eargs.Value != null && ((LinkedList<Entry>) eargs.Value).Count > 0) {
LinkedList<Entry> data = (LinkedList<Entry>) eargs.Value;
// AdrConverter doesn't support LinkedLists
Entry[] entries = new Entry[data.Count];
data.CopyTo(entries, 0);
Hashtable[] ht_entries = new Hashtable[entries.Length];
int index = 0;
foreach(Entry entry in entries) {
ht_entries[index++] = (Hashtable) entry;
}
string dir_path, filename;
string file_path = GeneratePath(key, out dir_path, out filename);
if(!Directory.Exists(dir_path)) {
Directory.CreateDirectory(dir_path);
}
using (FileStream fs = File.Open(file_path, FileMode.Create)) {
AdrConverter.Serialize(ht_entries, fs);
}
}
}
/**
<summary>This adds an entry and should only be called if no such entry
exists, as it does not look to see if a duplicate entry already exists.
This creates a new LinkedList if this is the first entry for the specific
key and stores it in the _data hashtable. This increments count.</summary>
<remarks>Because data is stored by non-decreasing end time, we must place
this at the correct position, which by starting at the last entry is
right after the first entry that has a shorter end time.</remarks>
<param name="entry">The data to store.</param>
*/
public void AddEntry(Entry entry) {
CheckEntries();
LinkedList<Entry> data = (LinkedList<Entry>) _data[entry.Key];
if(data == null) {
list_of_keys.AddLast(entry.Key);
data = new LinkedList<Entry>();
_data[entry.Key] = data;
}
LinkedListNode<Entry> ent = data.Last;
while(ent != null) {
if(entry.EndTime > ent.Value.EndTime) {
data.AddAfter(ent, entry);
break;
}
ent = ent.Previous;
}
if(ent == null) {
data.AddFirst(entry);
}
count++;
}