Merge pull request #971 from narfbg/develop-db-driver

Improve the base database driver class

1 files changed, 114 insertions, 151 deletions

diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index 9f1a0b895..d3359e13e 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -99,9 +99,13 @@ abstract class CI_DB_driver {
 	 */
 	public function initialize()
 	{
-		// If an existing connection resource is available
-		// there is no need to connect and select the database
-		if (is_resource($this->conn_id) OR is_object($this->conn_id))
+		/* If an established connection is available, then there's
+		 * no need to connect and select the database.
+		 *
+		 * Depending on the database driver, conn_id can be either
+		 * boolean TRUE, a resource or an object.
+		 */
+		if ($this->conn_id)
 		{
 			return TRUE;
 		}
@@ -283,17 +287,13 @@ abstract class CI_DB_driver {
 		{
 			log_message('error', 'Invalid query: '.$sql);
 
-			if ($this->db_debug)
-			{
-				return $this->display_error('db_invalid_query');
-			}
-			return FALSE;
+			return ($this->db_debug) ? $this->display_error('db_invalid_query') : FALSE;
 		}
 
 		// Verify table prefix and replace if necessary
-		if ( ($this->dbprefix != '' AND $this->swap_pre != '') AND ($this->dbprefix != $this->swap_pre) )
+		if ($this->dbprefix != '' && $this->swap_pre != '' && $this->dbprefix != $this->swap_pre)
 		{
-			$sql = preg_replace("/(\W)".$this->swap_pre."(\S+?)/", "\\1".$this->dbprefix."\\2", $sql);
+			$sql = preg_replace('/(\W)'.$this->swap_pre.'(\S+?)/', '\\1'.$this->dbprefix.'\\2', $sql);
 		}
 
 		// Compile binds if needed
@@ -305,15 +305,12 @@ abstract class CI_DB_driver {
 		// Is query caching enabled? If the query is a "read type"
 		// we will load the caching class and return the previously
 		// cached query if it exists
-		if ($this->cache_on == TRUE AND stristr($sql, 'SELECT'))
+		if ($this->cache_on == TRUE && stripos($sql, 'SELECT') !== FALSE && $this->_cache_init())
 		{
-			if ($this->_cache_init())
+			$this->load_rdriver();
+			if (FALSE !== ($cache = $this->CACHE->read($sql)))
 			{
-				$this->load_rdriver();
-				if (FALSE !== ($cache = $this->CACHE->read($sql)))
-				{
-					return $cache;
-				}
+				return $cache;
 			}
 		}
 
@@ -352,13 +349,7 @@ abstract class CI_DB_driver {
 				$this->trans_complete();
 
 				// Display errors
-				return $this->display_error(
-								array(
-									'Error Number: '.$error['code'],
-									$error['message'],
-									$sql
-								)
-							);
+				return $this->display_error(array('Error Number: '.$error['code'], $error['message'], $sql));
 			}
 
 			return FALSE;
@@ -382,7 +373,7 @@ abstract class CI_DB_driver {
 		{
 			// If caching is enabled we'll auto-cleanup any
 			// existing files related to this particular URI
-			if ($this->cache_on == TRUE AND $this->cache_autodel == TRUE AND $this->_cache_init())
+			if ($this->cache_on == TRUE && $this->cache_autodel == TRUE && $this->_cache_init())
 			{
 				$this->CACHE->delete();
 			}
@@ -404,9 +395,9 @@ abstract class CI_DB_driver {
 
 		$RES->num_rows	= $RES->num_rows();
 
-		// Is query caching enabled?  If so, we'll serialize the
+		// Is query caching enabled? If so, we'll serialize the
 		// result object and save it to a cache file.
-		if ($this->cache_on == TRUE AND $this->_cache_init())
+		if ($this->cache_on == TRUE && $this->_cache_init())
 		{
 			// We'll create a new instance of the result object
 			// only without the platform specific driver since
@@ -415,9 +406,9 @@ abstract class CI_DB_driver {
 			// result object, so we'll have to compile the data
 			// and save it)
 			$CR = new CI_DB_result();
-			$CR->num_rows		= $RES->num_rows();
 			$CR->result_object	= $RES->result_object();
 			$CR->result_array	= $RES->result_array();
+			$CR->num_rows		= $RES->num_rows();
 
 			// Reset these since cached objects can not utilize resource IDs.
 			$CR->conn_id		= NULL;
@@ -608,7 +599,8 @@ abstract class CI_DB_driver {
 
 		// The count of bind should be 1 less then the count of segments
 		// If there are more bind arguments trim it down
-		if (count($binds) >= count($segments)) {
+		if (count($binds) >= count($segments))
+		{
 			$binds = array_slice($binds, 0, count($segments)-1);
 		}
 
@@ -617,8 +609,7 @@ abstract class CI_DB_driver {
 		$i = 0;
 		foreach ($binds as $bind)
 		{
-			$result .= $this->escape($bind);
-			$result .= $segments[++$i];
+			$result .= $this->escape($bind).$segments[++$i];
 		}
 
 		return $result;
@@ -689,15 +680,15 @@ abstract class CI_DB_driver {
 	{
 		if (is_string($str) OR method_exists($str, '__toString'))
 		{
-			$str = "'".$this->escape_str($str)."'";
+			return "'".$this->escape_str($str)."'";
 		}
 		elseif (is_bool($str))
 		{
-			$str = ($str === FALSE) ? 0 : 1;
+			return ($str === FALSE) ? 0 : 1;
 		}
 		elseif (is_null($str))
 		{
-			$str = 'NULL';
+			return 'NULL';
 		}
 
 		return $str;
@@ -733,13 +724,7 @@ abstract class CI_DB_driver {
 	public function primary($table = '')
 	{
 		$fields = $this->list_fields($table);
-
-		if ( ! is_array($fields))
-		{
-			return FALSE;
-		}
-
-		return current($fields);
+		return is_array($fields) ? current($fields) : FALSE;
 	}
 
 	// --------------------------------------------------------------------
@@ -759,35 +744,40 @@ abstract class CI_DB_driver {
 
 		if (FALSE === ($sql = $this->_list_tables($constrain_by_prefix)))
 		{
-			if ($this->db_debug)
-			{
-				return $this->display_error('db_unsupported_function');
-			}
-			return FALSE;
+			return ($this->db_debug) ? $this->display_error('db_unsupported_function') : FALSE;
 		}
 
-		$retval = array();
+		$this->data_cache['table_names'] = array();
 		$query = $this->query($sql);
 
-		if ($query->num_rows() > 0)
+		foreach ($query->result_array() as $row)
 		{
-			$table = FALSE;
-			$rows = $query->result_array();
-			$key = (($row = current($rows)) && in_array('table_name', array_map('strtolower', array_keys($row))));
-
-			if ($key)
+			// Do we know from which column to get the table name?
+			if ( ! isset($key))
 			{
-				$table = array_key_exists('TABLE_NAME', $row) ? 'TABLE_NAME' : 'table_name';
+				if (isset($row['table_name']))
+				{
+					$key = 'table_name';
+				}
+				elseif (isset($row['TABLE_NAME']))
+				{
+					$key = 'TABLE_NAME';
+				}
+				else
+				{
+					/* We have no other choice but to just get the first element's key.
+					 * Due to array_shift() accepting it's argument by reference, if
+					 * E_STRICT is on, this would trigger a warning. So we'll have to
+					 * assign it first.
+					 */
+					$key = array_keys($row);
+					$key = array_shift($key);
+				}
 			}
 
-			foreach ($rows as $row)
-			{
-				$retval[] = ( ! $table) ? current($row) : $row[$table];
-			}
+			$this->data_cache['table_names'][] = $row[$key];
 		}
 
-		$this->data_cache['table_names'] = $retval;
-
 		return $this->data_cache['table_names'];
 	}
 
@@ -821,38 +811,45 @@ abstract class CI_DB_driver {
 
 		if ($table == '')
 		{
-			if ($this->db_debug)
-			{
-				return $this->display_error('db_field_param_missing');
-			}
-			return FALSE;
+			return ($this->db_debug) ? $this->display_error('db_field_param_missing') : FALSE;
 		}
 
 		if (FALSE === ($sql = $this->_list_columns($table)))
 		{
-			if ($this->db_debug)
-			{
-				return $this->display_error('db_unsupported_function');
-			}
-			return FALSE;
+			return ($this->db_debug) ? $this->display_error('db_unsupported_function') : FALSE;
 		}
 
 		$query = $this->query($sql);
+		$this->data_cache['field_names'][$table] = array();
 
-		$retval = array();
 		foreach ($query->result_array() as $row)
 		{
-			if (isset($row['COLUMN_NAME']))
-			{
-				$retval[] = $row['COLUMN_NAME'];
-			}
-			else
+			// Do we know from where to get the column's name?
+			if ( ! isset($key))
 			{
-				$retval[] = current($row);
+				if (isset($row['column_name']))
+				{
+					$key = 'column_name';
+				}
+				elseif (isset($row['COLUMN_NAME']))
+				{
+					$key = 'COLUMN_NAME';
+				}
+				else
+				{
+					/* We have no other choice but to just get the first element's key.
+					 * Due to array_shift() accepting it's argument by reference, if
+					 * E_STRICT is on, this would trigger a warning. So we'll have to
+					 * assign it first.
+					 */
+					$key = array_keys($row);
+					$key = array_shift($key);
+				}
 			}
+
+			$this->data_cache['field_names'][$table][] = $row[$key];
 		}
 
-		$this->data_cache['field_names'][$table] = $retval;
 		return $this->data_cache['field_names'][$table];
 	}
 
@@ -867,7 +864,7 @@ abstract class CI_DB_driver {
 	 */
 	public function field_exists($field_name, $table_name)
 	{
-		return ( ! in_array($field_name, $this->list_fields($table_name))) ? FALSE : TRUE;
+		return in_array($field_name, $this->list_fields($table_name));
 	}
 
 	// --------------------------------------------------------------------
@@ -882,15 +879,10 @@ abstract class CI_DB_driver {
 	{
 		if ($table == '')
 		{
-			if ($this->db_debug)
-			{
-				return $this->display_error('db_field_param_missing');
-			}
-			return FALSE;
+			return ($this->db_debug) ? $this->display_error('db_field_param_missing') : FALSE;
 		}
 
 		$query = $this->query($this->_field_data($this->protect_identifiers($table, TRUE, NULL, FALSE)));
-
 		return $query->field_data();
 	}
 
@@ -905,8 +897,7 @@ abstract class CI_DB_driver {
 	 */
 	public function insert_string($table, $data)
 	{
-		$fields = array();
-		$values = array();
+		$fields = $values = array();
 
 		foreach ($data as $key => $val)
 		{
@@ -979,13 +970,7 @@ abstract class CI_DB_driver {
 	 */
 	protected function _has_operator($str)
 	{
-		$str = trim($str);
-		if ( ! preg_match("/(\s|<|>|!|=|is null|is not null)/i", $str))
-		{
-			return FALSE;
-		}
-
-		return TRUE;
+		return (bool) preg_match('/(\s|<|>|!|=|IS NULL|IS NOT NULL)/i', trim($str));
 	}
 
 	// --------------------------------------------------------------------
@@ -1008,25 +993,12 @@ abstract class CI_DB_driver {
 
 		if ( ! function_exists($function))
 		{
-			if ($this->db_debug)
-			{
-				return $this->display_error('db_unsupported_function');
-			}
-			return FALSE;
+			return ($this->db_debug) ? $this->display_error('db_unsupported_function') : FALSE;
 		}
-		else
-		{
-			$args = (func_num_args() > 1) ? array_splice(func_get_args(), 1) : null;
 
-			if (is_null($args))
-			{
-				return call_user_func($function);
-			}
-			else
-			{
-				return call_user_func_array($function, $args);
-			}
-		}
+		return (func_num_args() > 1)
+			? call_user_func_array($function, array_splice(func_get_args(), 1))
+			: call_user_func($function);
 	}
 
 	// --------------------------------------------------------------------
@@ -1051,8 +1023,7 @@ abstract class CI_DB_driver {
 	 */
 	public function cache_on()
 	{
-		$this->cache_on = TRUE;
-		return TRUE;
+		return $this->cache_on = TRUE;
 	}
 
 	// --------------------------------------------------------------------
@@ -1064,8 +1035,7 @@ abstract class CI_DB_driver {
 	 */
 	public function cache_off()
 	{
-		$this->cache_on = FALSE;
-		return FALSE;
+		return $this->cache_on = FALSE;
 	}
 
 
@@ -1078,11 +1048,9 @@ abstract class CI_DB_driver {
 	 */
 	public function cache_delete($segment_one = '', $segment_two = '')
 	{
-		if ( ! $this->_cache_init())
-		{
-			return FALSE;
-		}
-		return $this->CACHE->delete($segment_one, $segment_two);
+		return ($this->_cache_init())
+			? $this->CACHE->delete($segment_one, $segment_two)
+			: FALSE;
 	}
 
 	// --------------------------------------------------------------------
@@ -1094,12 +1062,9 @@ abstract class CI_DB_driver {
 	 */
 	public function cache_delete_all()
 	{
-		if ( ! $this->_cache_init())
-		{
-			return FALSE;
-		}
-
-		return $this->CACHE->delete_all();
+		return ($this->_cache_init())
+			? $this->CACHE->delete_all()
+			: FALSE;
 	}
 
 	// --------------------------------------------------------------------
@@ -1111,18 +1076,17 @@ abstract class CI_DB_driver {
 	 */
 	protected function _cache_init()
 	{
-		if (is_object($this->CACHE) AND class_exists('CI_DB_Cache'))
-		{
-			return TRUE;
-		}
-
-		if ( ! class_exists('CI_DB_Cache'))
+		if (class_exists('CI_DB_Cache'))
 		{
-			if ( ! @include(BASEPATH.'database/DB_cache.php'))
+			if (is_object($this->CACHE))
 			{
-				return $this->cache_off();
+				return TRUE;
 			}
 		}
+		elseif ( ! @include_once(BASEPATH.'database/DB_cache.php'))
+		{
+			return $this->cache_off();
+		}
 
 		$this->CACHE = new CI_DB_Cache($this); // pass db object to support multiple db connections and returned db objects
 		return TRUE;
@@ -1137,11 +1101,11 @@ abstract class CI_DB_driver {
 	 */
 	public function close()
 	{
-		if (is_resource($this->conn_id) OR is_object($this->conn_id))
+		if ($this->conn_id)
 		{
 			$this->_close($this->conn_id);
+			$this->conn_id = FALSE;
 		}
-		$this->conn_id = FALSE;
 	}
 
 	// --------------------------------------------------------------------
@@ -1173,9 +1137,7 @@ abstract class CI_DB_driver {
 		// Find the most likely culprit of the error by going through
 		// the backtrace until the source file is no longer in the
 		// database folder.
-
 		$trace = debug_backtrace();
-
 		foreach ($trace as $call)
 		{
 			if (isset($call['file']) && strpos($call['file'], BASEPATH.'database') === FALSE)
@@ -1183,7 +1145,6 @@ abstract class CI_DB_driver {
 				// Found it - use a relative path for safety
 				$message[] = 'Filename: '.str_replace(array(BASEPATH, APPPATH), '', $call['file']);
 				$message[] = 'Line Number: '.$call['line'];
-
 				break;
 			}
 		}
@@ -1201,7 +1162,7 @@ abstract class CI_DB_driver {
 	 * This function is used extensively by the Active Record class, and by
 	 * a couple functions in this class.
 	 * It takes a column or table name (optionally with an alias) and inserts
-	 * the table prefix onto it.  Some logic is necessary in order to deal with
+	 * the table prefix onto it. Some logic is necessary in order to deal with
 	 * column names that include the path. Consider a query like this:
 	 *
 	 * SELECT * FROM hostname.database.table.column AS c FROM hostname.database.table
@@ -1244,12 +1205,15 @@ abstract class CI_DB_driver {
 
 		// If the item has an alias declaration we remove it and set it aside.
 		// Basically we remove everything to the right of the first space
-		$alias = '';
 		if (strpos($item, ' ') !== FALSE)
 		{
-			$alias = strstr($item, " ");
+			$alias = strstr($item, ' ');
 			$item = substr($item, 0, - strlen($alias));
 		}
+		else
+		{
+			$alias = '';
+		}
 
 		// This is basically a bug fix for queries that use MAX, MIN, etc.
 		// If a parenthesis is found we know that we do not need to
@@ -1284,6 +1248,7 @@ abstract class CI_DB_driver {
 
 					$item = implode('.', $parts);
 				}
+
 				return $item.$alias;
 			}
 
@@ -1318,13 +1283,12 @@ abstract class CI_DB_driver {
 				}
 
 				// Verify table prefix and replace if necessary
-				if ($this->swap_pre != '' && strncmp($parts[$i], $this->swap_pre, strlen($this->swap_pre)) === 0)
+				if ($this->swap_pre != '' && strpos($parts[$i], $this->swap_pre) === 0)
 				{
-					$parts[$i] = preg_replace("/^".$this->swap_pre."(\S+?)/", $this->dbprefix."\\1", $parts[$i]);
+					$parts[$i] = preg_replace('/^'.$this->swap_pre.'(\S+?)/', $this->dbprefix.'\\1', $parts[$i]);
 				}
-
 				// We only add the table prefix if it does not already exist
-				if (substr($parts[$i], 0, strlen($this->dbprefix)) != $this->dbprefix)
+				elseif (strpos($parts[$i], $this->dbprefix) !== 0)
 				{
 					$parts[$i] = $this->dbprefix.$parts[$i];
 				}
@@ -1345,19 +1309,18 @@ abstract class CI_DB_driver {
 		if ($this->dbprefix != '')
 		{
 			// Verify table prefix and replace if necessary
-			if ($this->swap_pre != '' && strncmp($item, $this->swap_pre, strlen($this->swap_pre)) === 0)
+			if ($this->swap_pre != '' && strpos($item, $this->swap_pre) === 0)
 			{
-				$item = preg_replace("/^".$this->swap_pre."(\S+?)/", $this->dbprefix."\\1", $item);
+				$item = preg_replace('/^'.$this->swap_pre.'(\S+?)/', $this->dbprefix.'\\1', $item);
 			}
-
 			// Do we prefix an item with no segments?
-			if ($prefix_single == TRUE AND substr($item, 0, strlen($this->dbprefix)) != $this->dbprefix)
+			elseif ($prefix_single == TRUE && strpos($item, $this->dbprefix) !== 0)
 			{
 				$item = $this->dbprefix.$item;
 			}
 		}
 
-		if ($protect_identifiers === TRUE AND ! in_array($item, $this->_reserved_identifiers))
+		if ($protect_identifiers === TRUE && ! in_array($item, $this->_reserved_identifiers))
 		{
 			$item = $this->_escape_identifiers($item);
 		}