query_alter.class.php

<?php
/**
 * The class for manipulating ALTER query.
 *
 * newly supports multiple variants
 *
 * @package SQLite Integration
 * @author Kojima Toshiyasu
 */
class AlterQuery {
	/**
	 * Variable to store the rewritten query string.
	 * @var string
	 */
	public $_query = null;

	/**
	 * Function to split the query string to the tokens and call apropreate functions.
	 *
	 * @param string @query
	 * @parm string $query_type
	 * @return boolean | stirng
	 */
	public function rewrite_query($query, $query_type) {
		if (stripos($query, $query_type) === false) {
			return false;
		}
		$query = str_replace('`', '', $query);
		if (preg_match('/^\\s*(ALTER\\s*TABLE)\\s*(\\w+)?\\s*/ims', $query, $match)) {
			$tmp_query  = array();
			$tokens     = array();
			$re_command = '';
			$command    = str_ireplace($match[0], '', $query);
			$tmp_tokens['query_type'] = trim($match[1]);
			$tmp_tokens['table_name'] = trim($match[2]);
			//$command_array = $this->split_multiple($command);
			$command_array = explode(',', $command);

			$single_command = array_shift($command_array);
			if (!empty($command_array)) {
				$re_command  = 'ALTER TABLE ' . $tmp_tokens['table_name'] . ' ';
				$re_command .= implode(',', $command_array);
			}
			$command_tokens = $this->command_tokenizer($single_command);
			if (!empty($command_tokens)) {
				$tokens = array_merge($tmp_tokens, $command_tokens);
			} else {
				$this->_query = 'SELECT 1=1';
				return $this->_query;
			}
			$command_name = strtolower($tokens['command']);
			switch ($command_name) {
				case 'add column': case 'rename to': case 'add index': case 'drop index':
					$tmp_query = $this->handle_single_command($tokens);
					break;
				case 'add primary key':
					$tmp_query = $this->handle_add_primary_key($tokens);
					break;
				case 'drop primary key':
					$tmp_query = $this->handle_drop_primary_key($tokens);
					break;
				case 'modify column':
					$tmp_query = $this->handle_modify_command($tokens);
					break;
				case 'change column':
					$tmp_query = $this->handle_change_command($tokens);
					break;
				case 'alter column':
					$tmp_query = $this->handle_alter_command($tokens);
					break;
				default:
					break;
			}
			if (!is_array($tmp_query)) {
				$this->_query[] = $tmp_query;
			} else {
				$this->_query = $tmp_query;
			}
			if ($re_command != '') {
				$this->_query = array_merge($this->_query, array('recursion' => $re_command));
			}
		} else {
			$this->_query = 'SELECT 1=1';
		}
		return $this->_query;
	}
	/**
	 * Function to analyze ALTER TABLE command and sets the data to an array.
	 *
	 * @param string $command
	 * @return boolean|array
	 * @access private
	 */
	private function command_tokenizer($command) {
		$tokens = array();
		if (preg_match('/^(ADD|DROP|RENAME|MODIFY|CHANGE|ALTER)\\s*(\\w+)?\\s*(\\w+(\(.+\)|))?\\s*/ims', $command, $match)) {
			$the_rest = str_ireplace($match[0], '', $command);
			$match_1 = trim($match[1]);
			$match_2 = trim($match[2]);
			$match_3 = isset($match[3]) ? trim($match[3]) : '';
			switch (strtolower($match_1)) {
				case 'add':
					if (in_array(strtolower($match_2), array('fulltext', 'constraint', 'foreign'))) {
						break;
					} elseif (stripos('column', $match_2) !== false) {
						$tokens['command']     = $match_1.' '.$match_2;
						$tokens['column_name'] = $match_3;
						$tokens['column_def']  = trim($the_rest);
					} elseif (stripos('primary', $match_2) !== false) {
						$tokens['command']     = $match_1.' '.$match_2.' '.$match_3;
						$tokens['column_name'] = $the_rest;
					} elseif (stripos('unique', $match_2) !== false) {
						list($index_name, $col_name) = preg_split('/[\(\)]/s', trim($the_rest), -1, PREG_SPLIT_DELIM_CAPTURE);
						$tokens['unique']      = true;
						$tokens['command']     = $match_1.' '.$match_3;
						$tokens['index_name']  = trim($index_name);
						$tokens['column_name'] = '('.trim($col_name).')';
					} elseif (in_array(strtolower($match_2), array('index', 'key'))) {
						$tokens['command'] = $match_1.' '.$match_2;
						if ($match_3 == '') {
							$tokens['index_name'] = str_replace(array('(', ')'), '', $the_rest);
						} else {
							$tokens['index_name'] = $match_3;
						}
						$tokens['column_name'] = trim($the_rest);
					} else {
						$tokens['command']     = $match_1.' COLUMN';
						$tokens['column_name'] = $match_2;
						$tokens['column_def']  = $match_3.' '.$the_rest;
					}
					break;
				case 'drop':
					if (stripos('column', $match_2) !== false) {
						$tokens['command']     = $match_1.' '.$match_2;
						$tokens['column_name'] = trim($match_3);
					} elseif (stripos('primary', $match_2) !== false) {
						$tokens['command'] = $match_1.' '.$match_2.' '.$match_3;
					} elseif (in_array(strtolower($match_2), array('index', 'key'))) {
						$tokens['command']    = $match_1.' '.$match_2;
						$tokens['index_name'] = $match_3;
					} elseif (stripos('primary', $match_2) !== false) {
						$tokens['command'] = $match_1.' '.$match_2.' '.$match_3;
					} else {
						$tokens['command']     = $match_1.' COLUMN';
						$tokens['column_name'] = $match_2;
					}
					break;
				case 'rename':
					if (stripos('to', $match_2) !== false) {
						$tokens['command']     = $match_1.' '.$match_2;
						$tokens['column_name'] = $match_3;
					} else {
						$tokens['command']     = $match_1.' TO';
						$tokens['column_name'] = $match_2;
					}
					break;
				case 'modify':
					if (stripos('column', $match_2) !== false) {
						$tokens['command']     = $match_1.' '.$match_2;
						$tokens['column_name'] = $match_3;
						$tokens['column_def']  = trim($the_rest);
					} else {
						$tokens['command']     = $match_1.' COLUMN';
						$tokens['column_name'] = $match_2;
						$tokens['column_def']  = $match_3.' '.trim($the_rest);
					}
					break;
				case 'change':
					$the_rest = trim($the_rest);
					if (stripos('column', $match_2) !== false) {
						$tokens['command']    = $match_1.' '.$match_2;
						$tokens['old_column'] = $match_3;
						list($new_col)        = explode(' ', $the_rest);
						$tmp_col              = preg_replace('/\(.+?\)/im', '', $new_col);
						if (array_key_exists(strtolower($tmp_col), $this->array_types)) {
							$tokens['column_def'] = $the_rest;
						} else {
							$tokens['new_column'] = $new_col;
							$col_def              = str_replace($new_col, '', $the_rest);
							$tokens['column_def'] = trim($col_def);
						}
					} else {
						$tokens['command']    = $match_1.' column';
						$tokens['old_column'] = $match_2;
						$tmp_col              = preg_replace('/\(.+?\)/im', '', $match_3);
						if (array_key_exists(strtolower($tmp_col), $this->array_types)) {
							$tokens['column_def'] = $match_3 . ' ' . $the_rest;
						} else {
							$tokens['new_column'] = $match_3;
							$tokens['column_def'] = $the_rest;
						}
					}
					break;
				case 'alter':
					if (stripos('column', $match_2) !== false) {
						$tokens['command']     = $match_1.' '.$match_2;
						$tokens['column_name'] = $match_3;
						list($set_or_drop)     = explode(' ', $the_rest);
						if (stripos('set', $set_or_drop) !== false) {
							$tokens['default_command'] = 'SET DEFAULT';
							$default_value             = str_ireplace('set default', '', $the_rest);
							$tokens['default_value']   = trim($default_value);
						} else {
							$tokens['default_command'] = 'DROP DEFAULT';
						}
					} else {
						$tokens['command']     = $match_1.' COLUMN';
						$tokens['column_name'] = $match_2;
						if (stripos('set', $match_3) !== false) {
							$tokens['default_command'] = 'SET DEFAULT';
							$default_value             = str_ireplace('default', '', $the_rest);
							$tokens['default_value']   = trim($default_value);
						} else {
							$tokens['default_command'] = 'DROP DEFAULT';
						}
					}
					break;
				default:
					break;
			}
			return $tokens;
		}
	}
	/**
	 * Function to split multiple commands into an array and return it.
	 *
	 * This function is deprecated.
	 *
	 * @access private
	 * @param unknown $command
	 * @return multitype:string unknown Ambigous <string, unknown>
	 */
	private function split_multiple($command) {
		$out            = true;
		$command_array  = array();
		$command_string = '';
		$tokens         = preg_split('/\b/s', $command, -1, PREG_SPLIT_DELIM_CAPTURE);
		foreach ($tokens as $token) {
			switch (trim($token)) {
				case ';':
					break;
				case '(':
					$command_string .= $token;
					$out = false;
					break;
				case ')':
					$command_string .= $token;
					$out = true;
					break;
				case '),':
					$command_array[] = $command_string;
					$command_string  = '';
					$out = true;
					break;
				case ',':
					if ($out) {
						$command_array[] = $command_string;
						$command_string  = '';
					} else {
						$command_string .= $token;
					}
					break;
				default:
					$command_string .= $token;
					break;
			}
		}
		if (!empty($command_string)) {
			$command_array[] = $command_string;
		}
		return $command_array;
	}
	/**
	 * Function to handle single command.
	 *
	 * @access private
	 * @param array of string $queries
	 * @return string
	 */
	private function handle_single_command($queries) {
		$tokenized_query = $queries;
		if (stripos($tokenized_query['command'], 'add column') !== false) {
			$column_def = $this->convert_field_types($tokenized_query['column_name'], $tokenized_query['column_def']);
			$query = "ALTER TABLE {$tokenized_query['table_name']} ADD COLUMN {$tokenized_query['column_name']} $column_def";
		} elseif (stripos($tokenized_query['command'], 'rename') !== false) {
			$query = "ALTER TABLE {$tokenized_query['table_name']} RENAME TO {$tokenized_query['column_name']}";
		} elseif (stripos($tokenized_query['command'], 'add index') !== false) {
			$unique = isset($tokenized_query['unique']) ? 'UNIQUE' : '';
			$query = "CREATE $unique INDEX IF NOT EXISTS {$tokenized_query['index_name']} ON {$tokenized_query['table_name']} {$tokenized_query['column_name']}";
		} elseif (stripos($tokenized_query['command'], 'drop index') !== false) {
			$query = "DROP INDEX IF EXISTS {$tokenized_query['index_name']}";
		} else {
			$query = 'SELECT 1=1';
		}
		return $query;
	}
	/**
	 * Function to handle ADD PRIMARY KEY.
	 *
	 * @access private
	 * @param array of string $queries
	 * @return array of string
	 */
	private function handle_add_primary_key($queries) {
		$tokenized_query = $queries;
		$tbl_name        = $tokenized_query['table_name'];
		$temp_table      = 'temp_'.$tokenized_query['table_name'];
		$_wpdb = new PDODB();
		$query_obj = $_wpdb->get_results("SELECT sql FROM sqlite_master WHERE tbl_name='$tbl_name'");
		$_wpdb = null;
		for ($i = 0; $i < count($query_obj); $i++) {
			$index_queries[$i] = $query_obj[$i]->sql;
		}
		$table_query = array_shift($index_queries);
		$table_query = str_replace($tokenized_query['table_name'], $temp_table, $table_query);
		$table_query = rtrim($table_query, ')');
		$table_query = ", PRIMARY KEY {$tokenized_query['column_name']}";
		$query[] = $table_query;
		$query[] = "INSERT INTO $temp_table SELECT * FROM {$tokenized_query['table_name']}";
		$query[] = "DROP TABLE IF EXISTS {$tokenized_query['table_name']}";
		$query[] = "ALTER TABLE $temp_table RENAME TO {$tokenized_query['table_name']}";
		foreach ($index_queries as $index) {
			$query[] = $index;
		}
		return $query;
	}
	/**
	 * Function to handle DROP PRIMARY KEY.
	 *
	 * @access private
	 * @param array of string $queries
	 * @return array of string
	 */
	private function handle_drop_primary_key($queries) {
		$tokenized_query = $queries;
		$temp_table      = 'temp_'.$tokenized_query['table_name'];
		$_wpdb = new PDODB();
		$query_obj = $_wpdb->get_results("SELECT sql FROM sqlite_master WHERE tbl_name='{$tokenized_query['table_name']}'");
		$_wpdb = null;
		for ($i = 0; $i < count($query_obj); $i++) {
			$index_queries[$i] = $query_obj[$i]->sql;
		}
		$table_query = array_shift($index_queries);
		$pattern1    = '/^\\s*PRIMARY\\s*KEY\\s*\(.*\)/im';
		$pattern2    = '/^\\s*.*(PRIMARY\\s*KEY\\s*(:?AUTOINCREMENT|))\\s*(?!\()/im';
		if (preg_match($pattern1, $table_query, $match)) {
			$table_query = str_replace($match[0], '', $table_query);
		} elseif (preg_match($pattern2, $table_query, $match)) {
			$table_query = str_replace($match[1], '', $table_query);
		}
		$table_query = str_replace($tokenized_query['table_name'], $temp_table, $table_query);
		$query[]     = $table_query;
		$query[]     = "INSERT INTO $temp_table SELECT * FROM {$tokenized_query['table_name']}";
		$query[]     = "DROP TABLE IF EXISTS {$tokenized_query['table_name']}";
		$query[]     = "ALTER TABLE $temp_table RENAME TO {$tokenized_query['table_name']}";
		foreach ($index_queries as $index) {
			$query[] = $index;
		}
		return $query;
	}
	/**
	 * Function to handle MODIFY COLUMN.
	 *
	 * @access private
	 * @param array of string $queries
	 * @return string|array of string
	 */
	private function handle_modify_command($queries) {
		$tokenized_query = $queries;
		$temp_table      = 'temp_'.$tokenized_query['table_name'];
		$column_def      = $this->convert_field_types($tokenized_query['column_name'], $tokenized_query['column_def']);
		$_wpdb = new PDODB();
		$query_obj = $_wpdb->get_results("SELECT sql FROM sqlite_master WHERE tbl_name='{$tokenized_query['table_name']}'");
		$_wpdb = null;
		for ($i =0; $i < count($query_obj); $i++) {
			$index_queries[$i] = $query_obj[$i]->sql;
		}
		$create_query = array_shift($index_queries);
		if (stripos($create_query, $tokenized_query['column_name']) === false) {
			return 'SELECT 1=1';
		} elseif (preg_match("/{$tokenized_query['column_name']}\\s*{$column_def}\\s*[,)]/i", $create_query)) {
			return 'SELECT 1=1';
		}
		$create_query = preg_replace("/{$tokenized_query['table_name']}/i", $temp_table, $create_query);
		if (preg_match("/\\b{$tokenized_query['column_name']}\\s*.*(?=,)/ims", $create_query)) {
			$create_query = preg_replace("/\\b{$tokenized_query['column_name']}\\s*.*(?=,)/ims", "{$tokenized_query['column_name']} {$column_def}", $create_query);
		} elseif (preg_match("/\\b{$tokenized_query['column_name']}\\s*.*(?=\))/ims", $create_query)) {
			$create_query = preg_replace("/\\b{$tokenized_query['column_name']}\\s*.*(?=\))/ims", "{$tokenized_query['column_name']} {$column_def}", $create_query);
		}
		$query[] = $create_query;
		$query[] = "INSERT INTO $temp_table SELECT * FROM {$tokenized_query['table_name']}";
		$query[] = "DROP TABLE IF EXISTS {$tokenized_query['table_name']}";
		$query[] = "ALTER TABLE $temp_table RENAME TO {$tokenized_query['table_name']}";
		foreach ($index_queries as $index) {
			$query[] = $index;
		}
		return $query;
	}
	/**
	 * Function to handle CHANGE COLUMN.
	 *
	 * @access private
	 * @param array of string $queries
	 * @return string|array of string
	 */
	private function handle_change_command($queries) {
		$col_check       = false;
		$old_fields      = '';
		$new_fields      = '';
		$tokenized_query = $queries;
		$temp_table      = 'temp_'.$tokenized_query['table_name'];
		if (isset($tokenized_query['new_column'])) {
			$column_name = $tokenized_query['new_column'];
		} else {
			$column_name = $tokenized_query['old_column'];
		}
		$column_def = $this->convert_field_types($column_name, $tokenized_query['column_def']);
		$_wpdb = new PDODB();
		$col_obj = $_wpdb->get_results("SHOW COLUMNS FROM {$tokenized_query['table_name']}");
		foreach ($col_obj as $col) {
			if (stripos($col->Field, $tokenized_query['old_column']) !== false) $col_check = true;
			$old_fields .= $col->Field . ',';
		}
		if ($col_check == false) {
			$_wpdb = null;
			return 'SELECT 1=1';
		}
		$old_fields = rtrim($old_fields, ',');
		$new_fields = str_ireplace($tokenized_query['old_column'], $column_name, $old_fields);
		$query_obj  = $_wpdb->get_results("SELECT sql FROM sqlite_master WHERE tbl_name='{$tokenized_query['table_name']}'");
		$_wpdb = null;
		for ($i = 0; $i < count($query_obj); $i++) {
			$index_queries[$i] = $query_obj[$i]->sql;
		}
		$create_query = array_shift($index_queries);
		$create_query = preg_replace("/{$tokenized_query['table_name']}/i", $temp_table, $create_query);
		if (preg_match("/\\b{$tokenized_query['old_column']}\\s*(.+?)(?=,)/ims", $create_query, $match)) {
			if (stripos(trim($match[1]), $column_def) !== false) {
				return 'SELECT 1=1';
			} else {
				$create_query = preg_replace("/\\b{$tokenized_query['old_column']}\\s*.+?(?=,)/ims", "{$column_name} {$column_def}", $create_query, 1);
			}
		} elseif (preg_match("/\\b{$tokenized_query['old_column']}\\s*(.+?)(?=\))/ims", $create_query, $match)) {
			if (stripos(trim($match[1]), $column_def) !== false) {
				return 'SELECT 1=1';
			} else {
				$create_query = preg_replace("/\\b{$tokenized_query['old_column']}\\s*.*(?=\))/ims", "{$column_name} {$column_def}", $create_query, 1);
			}
		}
		$query[] = $create_query;
		$query[] = "INSERT INTO $temp_table ($new_fields) SELECT $old_fields FROM {$tokenized_query['table_name']}";
		$query[] = "DROP TABLE IF EXISTS {$tokenized_query['table_name']}";
		$query[] = "ALTER TABLE $temp_table RENAME TO {$tokenized_query['table_name']}";
		foreach ($index_queries as $index) {
			$query[] = $index;
		}
		return $query;
	}
	/**
	 * Function to handle ALTER COLUMN.
	 *
	 * @access private
	 * @param array of string $queries
	 * @return string|array of string
	 */
	private function handle_alter_command($queries) {
		$tokenized_query = $queries;
		$temp_table      = 'temp_'.$tokenized_query['table_name'];
		if (isset($tokenized_query['default_value'])) {
			$def_value = $this->convert_field_types($tokenized_query['column_name'], $tokenized_query['default_value']);
			$def_value = 'DEFAULT '.$def_value;
		} else {
			$def_value = null;
		}
		$_wpdb = new PDODB();
		$query_obj = $_wpdb->get_results("SELECT sql FROM sqlite_master WHERE tbl_name='{$tokenized_query['table_name']}'");
		$_wpdb = null;
		for ($i =0; $i < count($query_obj); $i++) {
			$index_queries[$i] = $query_obj[$i]->sql;
		}
		$create_query = array_shift($index_queries);
		if (stripos($create_query, $tokenized_query['column_name']) === false) {
			return 'SELECT 1=1';
		}
		if (preg_match("/\\s*({$tokenized_query['column_name']})\\s*(.*)?(DEFAULT\\s*.*)[,)]/im", $create_query, $match)) {
			$col_name        = trim($match[1]);
			$col_def         = trim($match[2]);
			$col_def_esc     = str_replace(array('(', ')'), array('\(', '\)'), $col_def);
			$checked_col_def = $this->convert_field_types($col_name, $col_def);
			$old_default     = trim($match[3]);
			$pattern         = "/$col_name\\s*$col_def_esc\\s*$old_default/im";
			if (is_null($def_value)) {
				$replacement = $col_name . ' ' . $checked_col_def;
			} else {
				$replacement = $col_name . ' ' . $checked_col_def . ' ' . $def_value;
			}
			$create_query = preg_replace($pattern, $replacement, $create_query);
			$create_query = str_ireplace($tokenized_query['table_name'], $temp_table, $create_query);
		} elseif (preg_match("/\\s*({$tokenized_query['column_name']})\\s*(.*)?[,)]/im", $create_query, $match)) {
			$col_name        = trim($match[1]);
			$col_def         = trim($match[2]);
			$col_def_esc     = str_replace(array('(', ')'), array('\(', '\)'), $col_def);
			$checked_col_def = $this->convert_field_types($col_name, $col_def);
			$pattern         = "/$col_name\\s*$col_def_esc/im";
			if (is_null($def_value)) {
				$replacement = $col_name . ' ' . $checked_col_def;
			} else {
				$replacement = $col_name . ' ' . $checked_col_def . ' ' . $def_value;
			}
			$create_query = preg_replace($pattern, $replacement, $create_query);
			$create_query = str_ireplace($tokenized_query['table_name'], $temp_table, $create_query);
		} else {
			return 'SELECT 1=1';
		}
		$query[] = $create_query;
		$query[] = "INSERT INTO $temp_table SELECT * FROM {$tokenized_query['table_name']}";
		$query[] = "DROP TABLE IF EXISTS {$tokenized_query['table_name']}";
		$query[] = "ALTER TABLE $temp_table RENAME TO {$tokenized_query['table_name']}";
			foreach ($index_queries as $index) {
			$query[] = $index;
		}
		return $query;
	}
	/**
	 * Function to change the field definition to SQLite compatible data type.
	 *
	 * @access private
	 * @param string $col_name
	 * @param string $col_def
	 * @return string
	 */
	private function convert_field_types($col_name, $col_def){
		$array_curtime = array('current_timestamp', 'current_time', 'current_date');
		$array_reptime = array("'0000-00-00 00:00:00'", "'0000-00-00 00:00:00'", "'0000-00-00'");
		$def_string    = str_replace('`', '', $col_def);
		foreach ($this->array_types as $o=>$r){
			$pattern = "/\\b$o\\s*(\([^\)]*\)*)?\\s*/ims";
			if (preg_match($pattern, $def_string)) {
				$def_string = preg_replace($pattern, "$r ", $def_string);
				break;
			}
		}
		$def_string = preg_replace('/unsigned/im', '', $def_string);
		$def_string = preg_replace('/auto_increment/im', 'PRIMARY KEY AUTOINCREMENT', $def_string);
		// when you use ALTER TABLE ADD, you can't use current_*. so we replace
		$def_string = str_ireplace($array_curtime, $array_reptime, $def_string);
		// colDef is enum
		$pattern_enum = '/enum\((.*?)\)([^,\)]*)/ims';
		if (preg_match($pattern_enum, $col_def, $matches)) {
			$def_string = 'TEXT' . $matches[2] . ' CHECK (' . $col_name . ' IN (' . $matches[1] . '))';
		}
		return $def_string;
	}
	/**
	 * Variable to store the data definition table.
	 *
	 * @access private
	 * @var associative array
	 */
	private $array_types = array(
		'bit'        => 'INTEGER', 'bool'       => 'INTEGER',
		'boolean'    => 'INTEGER', 'tinyint'    => 'INTEGER',
		'smallint'   => 'INTEGER', 'mediumint'  => 'INTEGER',
		'bigint'     => 'INTEGER', 'integer'    => 'INTEGER',
		'int'        => 'INTEGER', 'float'      => 'REAL',
		'double'     => 'REAL',    'decimal'    => 'REAL',
		'dec'        => 'REAL',    'numeric'    => 'REAL',
		'fixed'      => 'REAL',    'datetime'   => 'TEXT',
		'date'       => 'TEXT',    'timestamp'  => 'TEXT',
		'time'       => 'TEXT',    'year'       => 'TEXT',
		'varchar'    => 'TEXT',    'char'       => 'TEXT',
		'varbinary'  => 'BLOB',    'binary'     => 'BLOB',
		'tinyblob'   => 'BLOB',    'mediumblob' => 'BLOB',
		'longblob'   => 'BLOB',    'blob'       => 'BLOB',
		'tinytext'   => 'TEXT',    'mediumtext' => 'TEXT',
		'longtext'   => 'TEXT',    'text'       => 'TEXT'
	);
}
?>