Added table locking

Author: Noneatme

MysqliDb.php

@@ -81,7 +81,19 @@ class MysqliDb
      * @var array
      */
     protected $_groupBy = array();
-
+	
+	/**
+	 * Dynamic type list for tempromary locking tables. 
+	 * @var array
+	 */
+	protected $_tableLocks = array();
+	
+	/**
+	 * Variable which holds the current table lock method.
+	 * @var string
+	 */
+	protected $_tableLockMethod = "READ";
+	
     /**
      * Dynamic array that holds a combination of where condition/table data value types and parameter references
      * @var array
@@ -1092,7 +1104,124 @@ public function groupBy($groupByField)
         $this->_groupBy[] = $groupByField;
         return $this;
     }
+	
+	
+	/**
+	 * This method sets the current table lock method.
+	 * 
+	 * @author Jonas Barascu
+	 * @param  string   $method The table lock method. Can be READ or WRITE.
+	 *                                                                 
+	 * @throws Exception
+	 * @return MysqliDb
+	 */
+	public function setLockMethod($method)
+	{
+		// Switch the uppercase string
+		switch(strtoupper($method)) {
+			// Is it READ or WRITE?
+			case "READ" || "WRITE":
+				// Succeed
+				$this->_tableLockMethod = $method;
+				break;
+			default:
+				// Else throw an exception
+				throw new Exception("Bad lock type: Can be either READ or WRITE");
+				break;
+		}
+		return $this;
+	}
+	
+	/**
+	 * Locks a table for R/W action.
+	 * 
+	 * @author Jonas Barascu
+	 * @param string  $table The table to be locked. Can be a table or a view.
+	 *                       
+	 * @throws Exception
+	 * @return MysqliDb if succeeeded;
+	 */
+	public function lock($table)
+	{
+		// Main Query
+		$this->_query = "LOCK TABLES";
+		
+		// Is the table an array?
+		if(gettype($table) == "array") {
+			// Loop trough it and attach it to the query
+			foreach($table as $key => $value) {
+				if(gettype($value) == "string") {
+					if($key > 0) {
+						$this->_query .= ",";
+					}
+					$this->_query .= " ".self::$prefix.$value." ".$this->_tableLockMethod;
+				}
+			}
+		}
+		else
+		{
+			// Build the table prefix
+			$table = self::$prefix . $table;
+
+			// Build the query
+			$this->_query = "LOCK TABLES ".$table." ".$this->_tableLockMethod;
+		}
+
+		// Exceute the query unprepared because LOCK only works with unprepared statements.
+		$result = $this->queryUnprepared($this->_query);
+			
+		// Reset the query
+		$this->reset();
+
+		// Are there rows modified?
+		if($result) {	
+			// Return true
+			// We can't return ourself because if one table gets locked, all other ones get unlocked!
+			return true;
+		}
+		// Something went wrong
+		else {
+			throw new Exception("Locking of table ".$table." failed");
+		}
+
+		// Return the success value
+		return false;
+	}
+	
+	/**
+	 * Unlocks all tables in a database.
+	 * Also commits transactions.
+	 * 
+	 * @author Jonas Barascu
+	 * @return MysqliDb
+	 */
+	public function unlock()
+	{
+		// Build the query
+		$this->_query = "UNLOCK TABLES";
+
+		// Exceute the query unprepared because UNLOCK and LOCK only works with unprepared statements.
+		$result = $this->queryUnprepared($this->_query);
 
+		// Reset the query
+		$this->reset();
+
+		// Are there rows modified?
+		if($result) {
+			// return self
+			return $this;
+		}
+		// Something went wrong
+		else {
+			throw new Exception("Unlocking of tables failed");
+		}
+		
+	
+		// Return self
+		return $this;
+	}
+
+	
     /**
      * This methods returns the ID of the last inserted item
      *
@@ -2087,4 +2216,4 @@ public function paginate ($table, $page, $fields = null) {
     }
 }
 
-// END class
+// END class