3.0.0. // TODO: Think about what expire time to use on local copy. // Actual expire value not available, maybe store in note? include_once('Mem_RackAware.php'); class Memcache_Dir extends Memcache_RackAware{ // constructor function function __construct(){ $this->dupLimit = 2; // A note is of the form ,,..., up to dupLimit. $this->rackConstruct(); // constructor for RackAware, provides $this->local which is the rack // number this machine should use, and $this->racks which // is an array of Memcache instances indexed by rack number. // So $this->racks[$this->local] would be the closest memcache // instance. //echo "Dir\n"; } // addServer provided by Memcache_RackAware /**************************************************************/ function add($key,$value,$flags = 0,$expire = 0){ // Add item with key // First check to see if its in local by doing an append of ''. // This will return true if it exists (and won't touch it, or // change expire) // or false if it doesn't exist. if($this->racks[$this->local]->append($key,'') === TRUE){ return false; // exists in local cache, so must exist in // centralized cluster as well } // now add note to centralized, return false if it fails (stored elsewhere) if(!$this->racks[0]->add($key,$this->local,$flags,$expire)){ // Just store this rack number, replicated racks will use comma return false; // exists in centralized cluster, so return false } // Now we've got to put the data in local, so use a set to be sure $this->racks[$this->local]->set($key,$value,$flags,$expire); return true; } /**************************/ function connect($host,$port,$timeout = 1){ return self::addServer($host,$port,TRUE,1,$timeout); } /**************************/ function delete($key,$timeout = 0){ // Delete data with key. We'll only return failure if // centralized failed // Get duplication info $dup = $this->racks[0]->get($key); if($dup === FALSE){ return false; // doesn't exists in centralized cluster, // so return false } // Delete centralized and duplicates $this->racks[0]->delete($key,$timeout); foreach(explode(',',$dup) as $d){ $this->racks[$d]->delete($key,$timeout); } return TRUE; } /**************************/ function flush(){ // flush all racks! foreach($this->racks as $r){ $r->flush(); } } /**************************/ function get($key, &$flags = 0, &$cas = ''){ // Validate all these flags and cas stuff works // Get local, otherwise get note and get it $ret = $this->racks[$this->local]->get($key,$flags,$cas); if($ret !== FALSE){ return $ret; } // go get note $note = $this->racks[0]->get($key); if($note === FALSE){ return FALSE; } $rep = explode(',',$note); $order = range(0,count($rep) - 1); // here we could optimize by choosing a close copy shuffle($order); $succ = 0; foreach($order as $o){ $ret = $this->racks[$rep[$o]]->get($key,$flags,$cas); if($ret !== FALSE){$succ = 1; break;} } if($succ == 0){return FALSE;} // move local? if(count($rep) < $this->dupLimit){ $this->racks[0]->append($key,',' . $this->local); $this->racks[$this->local]->set($key,$ret); // never expire } return $ret; } /**************************/ function replace($key, $value,$flag = 0,$expire = 0){ // Replace should return false if the item doesn't already exist. // So check to see if a note exists on the central, and if so just // do a set so it always works if($this->racks[0]->get($key) !== FALSE){ return $this->set($key,$value,$flag,$expire); } return false; } /**************************/ function decrement($key, $amt = 1, $exptime = 0){ // First get note, if it exists do a decrement on all, and if the // others don't match the first, set them to match // Optionaly we could remove all dups and let gets re-distribute $flags = 0; $note = $this->racks[0]->get($key,$flags); if($note === FALSE){ return FALSE; } $rep = explode(',',$note); $correct = $this->racks[$rep[0]]->decr($key,$amt,$exptime); foreach($rep as $r){ if($r =! $rep[0]){ $n = $this->racks[$r]->decr($key,$amt,$exptime); if($n =! $correct){ $this->racks[$r]->set($key,$correct,$exptime); } } } return $correct; } /**************************/ function increment($key, $amt = 1, $exptime = 0){ // First get note, if it exists do a increment on all, and if the // others don't match the first, set them to match // Optionaly we could remove all dups and let gets re-distribute $flags = 0; $note = $this->racks[0]->get($key,$flags); if($note === FALSE){ return FALSE; } $rep = explode(',',$note); $correct = $this->racks[$rep[0]]->incr($key,$amt,$exptime); foreach($rep as $r){ if($r =! $rep[0]){ $n = $this->racks[$r]->incr($key,$amt,$exptime); if($n =! $correct){ $this->racks[$r]->set($key,$correct,$exptime); } } } return $correct; } /**************************/ function set($key,$value,$flags = 0,$expire = 0){ // a Set clears out duplicates! // we must get the note before overwriting it so to delete $note = $this->racks[0]->get($key); if($note !== FALSE){ $rep = explode(',',$note); foreach($rep as $r){ $this->racks[$r]->delete($key); } } // now add note to centralized if(!$this->racks[0]->set($key,$this->local,$flags,$expire)){ // Just store this rack number, replicated racks will use comma return FALSE; } // Now we've got to put the data in local if(!$this->racks[$this->local]->set($key,$value,$flags,$expire)){ // hm, local failed, so remove central note $this->racks[0]->delete($key); return FALSE; } //we'll return false if any returned false, though you won't know // which rack failed. return TRUE; } function findServer($key){ return $this->racks[$this->local]->findServer($key); } } ?>