Websites/perf.webkit.org/public/include/db.php - WebKit - Git at Google

 <?php

 function ends_with($str, $key) {
     return strrpos($str, $key) == strlen($str) - strlen($key);
 }

 function ctype_alnum_underscore($str) {
     return ctype_alnum(str_replace('_', '', $str));
 }

 function &array_ensure_item_has_array(&$array, $key) {
     if (!array_key_exists($key, $array))
         $array[$key] = array();
     return $array[$key];
 }

 function array_get($array, $key, $default = NULL) {
     if (!array_key_exists($key, $array))
         return $default;
     return $array[$key];
 }

 function array_set_default(&$array, $key, $default) {
     if (!array_key_exists($key, $array))
         $array[$key] = $default;
 }

 $_config = NULL;

 define('CONFIG_DIR', realpath(dirname(__FILE__) . '/../../'));

 function config($key, $default = NULL) {
     global $_config;
     if (!$_config) {
         $file_path = getenv('ORG_WEBKIT_PERF_CONFIG_PATH');
         if (!$file_path)
             $file_path = CONFIG_DIR . '/config.json';
         $_config = json_decode(file_get_contents($file_path), true);
     }
     return array_get($_config, $key, $default);
 }

 function config_path($key, $path) {
     return CONFIG_DIR . '/' . config($key) . '/' . $path;
 }

 function same_till_last_occurrence_of_string($main_string, $comparing_string, $compare_to_last_position_string) {
     if (!$compare_to_last_position_string)
         return !strcmp($main_string, $comparing_string);

     $position_in_main_string = strrpos($main_string, $compare_to_last_position_string);
     $position_in_comparing_string = strrpos($comparing_string, $compare_to_last_position_string);
     if ($position_in_main_string !== $position_in_comparing_string)
         return FALSE;
     if ($position_in_main_string === FALSE)
         return !strcmp($main_string, $comparing_string);
     return !substr_compare($main_string, $comparing_string, 0, $position_in_main_string);
 }

 function generate_json_data_with_elapsed_time_if_needed($filename, $object, $elapsed_time) {
     if (!assert(ctype_alnum(str_replace(array('-', '_', '.'), '', $filename))))
         return NULL;

     $target_file_path = config_path('dataDirectory', $filename);
     $object['elapsedTime'] = $elapsed_time;
     $content = json_encode($object);

     if (file_exists($target_file_path) && same_till_last_occurrence_of_string(file_get_contents($target_file_path), $content, 'elapsedTime'))
         return $content;

     $temp_file_path = tempnam(config_path('dataDirectory', ''), $filename . '-temp-');
     file_put_contents($temp_file_path, $content, LOCK_EX);
     return rename($temp_file_path, $target_file_path) ?  $content : NULL;
 }

 if (config('debug')) {
     error_reporting(E_ALL | E_STRICT);
     ini_set('display_errors', 'On');
 } else
     error_reporting(E_ERROR);

 date_default_timezone_set('UTC');

 class Database
 {
     private $connection = false;

     function __destruct() {
         if ($this->connection)
             pg_close($this->connection);
         $this->connection = false;
     }

     static function is_true($value) {
         return $value == 't';
     }

     static function to_database_boolean($value) {
         return $value ? 't' : 'f';
     }

     static function to_js_time($time_str) {
         $timestamp_in_ms = strtotime($time_str) * 1000;
         $dot_index = strrpos($time_str, '.');
         if ($dot_index !== FALSE) {
             // Keep 5 decimal digits as postgres timestamp may only have 5 decimal digits.
             // Multiply by 1000 ahead to avoid losing precision. 1538041792.670479 will become 1538041792.6705 on php.
             $timestamp_in_ms += round(floatval(substr($time_str, $dot_index)), 5) * 1000;
         }
         return intval($timestamp_in_ms);
     }

     static function escape_for_like($string) {
         return str_replace(array('\\', '_', '%'), array('\\\\', '\\_', '\\%'), $string);
     }

     function connect() {
         $databaseConfig = config('database');

         $host = $databaseConfig['host'];
         $port = $databaseConfig['port'];
         $dbname = $databaseConfig['name'];
         $user = $databaseConfig['username'];
         $password = $databaseConfig['password'];
         $connectionString = "host=$host port=$port dbname=$dbname user=$user password=$password";

         $sslConfigString = '';

         if (array_get($databaseConfig, 'ssl')) {
             $sslConfig = $databaseConfig['ssl'];
             $sslConfigString .= ' sslmode=' . array_get($sslConfig, 'mode', 'require');
             foreach (array('rootcert', 'cert', 'key') as $key) {
                 if (!array_get($sslConfig, $key))
                     continue;

                 $path = $sslConfig[$key];
                 if (strlen($path) && $path[0] !== '/')
                     $path = CONFIG_DIR . '/' . $path;

                 $sslConfigString .= " ssl$key=$path";
             }
         }

         $connectionString .= $sslConfigString;
         $this->connection = @pg_connect($connectionString);
         return $this->connection ? true : false;
     }

     private function prefixed_column_names($columns, $prefix = NULL) {
         if (!$prefix || !$columns)
             return join(', ', $columns);
         return $prefix . '_' . join(', ' . $prefix . '_', $columns);
     }

     private function prefixed_name($column, $prefix = NULL) {
         return $prefix ? $prefix . '_' . $column : $column;
     }

     private function prepare_params($params, &$placeholders, &$values, &$null_columns = NULL) {
         $column_names = array();

         $i = count($values) + 1;
         foreach (array_keys($params) as $name) {
             $current_value = $params[$name];
             if ($current_value === NULL && $null_columns !== NULL) {
                 array_push($null_columns, $name);
                 continue;
             }
             assert(ctype_alnum_underscore($name));
             array_push($column_names, $name);
             array_push($placeholders, '$' . $i);
             if (is_bool($current_value))
                 $current_value = $this->to_database_boolean($current_value);
             array_push($values, $current_value);
             $i++;
         }

         return $column_names;
     }

     private function select_conditions_with_null_columns($prefix, $column_names, $placeholders, $null_columns) {
         $column_names = $this->prefixed_column_names($column_names, $prefix);
         $placeholders = join(', ', $placeholders);

         if (!$column_names && !$placeholders)
             $column_names = $placeholders = '1';
         $query = "($column_names) = ($placeholders)";
         foreach ($null_columns as $column_name)
             $query .= ' AND ' . $this->prefixed_name($column_name, $prefix) . ' IS NULL';
         return $query;
     }

     function insert_row($table, $prefix, $params, $returning = 'id') {
         $placeholders = array();
         $values = array();
         $column_names = $this->prepare_params($params, $placeholders, $values);

         assert(!$prefix || ctype_alnum_underscore($prefix));
         $column_names = $this->prefixed_column_names($column_names, $prefix);
         $placeholders = join(', ', $placeholders);

         $value_query = $column_names ? "($column_names) VALUES ($placeholders)" : ' VALUES (default)';
         if ($returning) {
             $returning_column_name = $this->prefixed_name($returning, $prefix);
             $rows = $this->query_and_fetch_all("INSERT INTO $table $value_query RETURNING $returning_column_name", $values);
             return $rows ? $rows[0][$returning_column_name] : NULL;
         }

         return $this->query_and_get_affected_rows("INSERT INTO $table $value_query", $values) == 1;
     }

     function select_or_insert_row($table, $prefix, $select_params, $insert_params = NULL, $returning = 'id') {
         return $this->_select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, FALSE, TRUE);
     }

     function update_or_insert_row($table, $prefix, $select_params, $insert_params = NULL, $returning = 'id') {
         return $this->_select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, TRUE, TRUE);
     }

     function update_row($table, $prefix, $select_params, $update_params, $returning = 'id') {
         return $this->_select_update_or_insert_row($table, $prefix, $select_params, $update_params, $returning, TRUE, FALSE);
     }

     private function _select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, $should_update, $should_insert) {
         $values = array();

         $select_placeholders = array();
         $select_null_columns = array();
         $select_column_names = $this->prepare_params($select_params, $select_placeholders, $values, $select_null_columns);
         $select_values = array_slice($values, 0);

         if ($insert_params === NULL)
             $insert_params = $select_params;
         $insert_placeholders = array();
         $insert_column_names = $this->prepare_params($insert_params, $insert_placeholders, $values);

         assert(!!$returning);
         assert(!$prefix || ctype_alnum_underscore($prefix));
         $returning_column_name = $returning == '*' ? '*' : $this->prefixed_name($returning, $prefix);

         $condition = $this->select_conditions_with_null_columns($prefix, $select_column_names, $select_placeholders, $select_null_columns);
         $query = "SELECT $returning_column_name FROM $table WHERE $condition";

         $insert_column_names = $this->prefixed_column_names($insert_column_names, $prefix);
         $insert_placeholders = join(', ', $insert_placeholders);

         // http://stackoverflow.com/questions/1109061/insert-on-duplicate-update-in-postgresql
         $rows = NULL;
         if ($should_update) {
             $rows = $this->query_and_fetch_all("UPDATE $table SET ($insert_column_names) = ($insert_placeholders)
                 WHERE $condition RETURNING $returning_column_name", $values);
         }
         if (!$rows && $should_insert) {
             $rows = $this->query_and_fetch_all("INSERT INTO $table ($insert_column_names) SELECT $insert_placeholders
                 WHERE NOT EXISTS ($query) RETURNING $returning_column_name", $values);
         }
         if (!$should_update && !$rows)
             $rows = $this->query_and_fetch_all($query, $select_values);

         return $rows ? ($returning == '*' ? $rows[0] : $rows[0][$returning_column_name]) : NULL;
     }

     function select_first_row($table, $prefix, $params, $order_by = NULL) {
         return $this->select_first_or_last_row($table, $prefix, $params, $order_by, FALSE);
     }

     function select_last_row($table, $prefix, $params, $order_by = NULL) {
         return $this->select_first_or_last_row($table, $prefix, $params, $order_by, TRUE);
     }

     private function select_first_or_last_row($table, $prefix, $params, $order_by, $descending_order) {
         $rows = $this->select_rows($table, $prefix, $params, $order_by, $descending_order, 0, 1);
         return $rows ? $rows[0] : NULL;
     }

     function select_rows($table, $prefix, $params,
         $order_by = NULL, $descending_order = FALSE, $offset = NULL, $limit = NULL) {

         $placeholders = array();
         $values = array();
         $null_columns = array();
         $column_names = $this->prepare_params($params, $placeholders, $values, $null_columns);
         $condition = $this->select_conditions_with_null_columns($prefix, $column_names, $placeholders, $null_columns);

         $query = "SELECT * FROM $table WHERE $condition";

         if ($order_by) {
             if (!is_array($order_by))
                 $order_by = array($order_by);

             $order_columns = array();
             foreach ($order_by as $order_key) {
                 assert(ctype_alnum_underscore($order_key));
                 $order_column = $this->prefixed_name($order_key, $prefix) . ' ' . ($descending_order? 'DESC' : 'ASC');
                 array_push($order_columns, $order_column);
             }
             $query .= ' ORDER BY ' . join(', ', $order_columns);
         }
         if ($offset !== NULL)
             $query .= ' OFFSET ' . intval($offset);
         if ($limit !== NULL)
             $query .= ' LIMIT ' . intval($limit);

         return $this->query_and_fetch_all($query, $values);
     }

     function query_and_get_affected_rows($query, $params = array()) {
         if (!$this->connection)
             return FALSE;
         $result = pg_query_params($this->connection, $query, $params);
         if (!$result)
             return FALSE;
         return pg_affected_rows($result);
     }

     function query_and_fetch_all($query, $params = array()) {
         if (!$this->connection)
             return NULL;
         $result = pg_query_params($this->connection, $query, $params);
         if (!$result)
             return NULL;
         if (pg_num_rows($result) == 0)
             return array();
         return pg_fetch_all($result);
     }

     function query($query, $params = array()) {
         if (!$this->connection)
             return FALSE;
         return pg_query_params($this->connection, $query, $params);
     }

     function fetch_next_row($result) {
         return pg_fetch_assoc($result);
     }

     function fetch_table($table_name, $column_to_be_ordered_by = null) {
         if (!$this->connection || !ctype_alnum_underscore($table_name) || ($column_to_be_ordered_by && !ctype_alnum_underscore($column_to_be_ordered_by)))
             return false;
         $clauses = '';
         if ($column_to_be_ordered_by)
             $clauses .= 'ORDER BY ' . $column_to_be_ordered_by;
         return $this->query_and_fetch_all("SELECT * FROM $table_name $clauses");
     }

     function begin_transaction() {
         return $this->connection and pg_query($this->connection, "BEGIN");
     }

     function commit_transaction() {
         return $this->connection and pg_query($this->connection, 'COMMIT');
     }

     function rollback_transaction() {
         return $this->connection and pg_query($this->connection, 'ROLLBACK');
     }

 }

 ?>
	<?php

	function ends_with($str, $key) {
	return strrpos($str, $key) == strlen($str) - strlen($key);
	}

	function ctype_alnum_underscore($str) {
	return ctype_alnum(str_replace('_', '', $str));
	}

	function &array_ensure_item_has_array(&$array, $key) {
	if (!array_key_exists($key, $array))
	$array[$key] = array();
	return $array[$key];
	}

	function array_get($array, $key, $default = NULL) {
	if (!array_key_exists($key, $array))
	return $default;
	return $array[$key];
	}

	function array_set_default(&$array, $key, $default) {
	if (!array_key_exists($key, $array))
	$array[$key] = $default;
	}

	$_config = NULL;

	define('CONFIG_DIR', realpath(dirname(__FILE__) . '/../../'));

	function config($key, $default = NULL) {
	global $_config;
	if (!$_config) {
	$file_path = getenv('ORG_WEBKIT_PERF_CONFIG_PATH');
	if (!$file_path)
	$file_path = CONFIG_DIR . '/config.json';
	$_config = json_decode(file_get_contents($file_path), true);
	}
	return array_get($_config, $key, $default);
	}

	function config_path($key, $path) {
	return CONFIG_DIR . '/' . config($key) . '/' . $path;
	}

	function same_till_last_occurrence_of_string($main_string, $comparing_string, $compare_to_last_position_string) {
	if (!$compare_to_last_position_string)
	return !strcmp($main_string, $comparing_string);

	$position_in_main_string = strrpos($main_string, $compare_to_last_position_string);
	$position_in_comparing_string = strrpos($comparing_string, $compare_to_last_position_string);
	if ($position_in_main_string !== $position_in_comparing_string)
	return FALSE;
	if ($position_in_main_string === FALSE)
	return !strcmp($main_string, $comparing_string);
	return !substr_compare($main_string, $comparing_string, 0, $position_in_main_string);
	}

	function generate_json_data_with_elapsed_time_if_needed($filename, $object, $elapsed_time) {
	if (!assert(ctype_alnum(str_replace(array('-', '_', '.'), '', $filename))))
	return NULL;

	$target_file_path = config_path('dataDirectory', $filename);
	$object['elapsedTime'] = $elapsed_time;
	$content = json_encode($object);

	if (file_exists($target_file_path) && same_till_last_occurrence_of_string(file_get_contents($target_file_path), $content, 'elapsedTime'))
	return $content;

	$temp_file_path = tempnam(config_path('dataDirectory', ''), $filename . '-temp-');
	file_put_contents($temp_file_path, $content, LOCK_EX);
	return rename($temp_file_path, $target_file_path) ? $content : NULL;
	}

	if (config('debug')) {
	error_reporting(E_ALL \| E_STRICT);
	ini_set('display_errors', 'On');
	} else
	error_reporting(E_ERROR);

	date_default_timezone_set('UTC');

	class Database
	{
	private $connection = false;

	function __destruct() {
	if ($this->connection)
	pg_close($this->connection);
	$this->connection = false;
	}

	static function is_true($value) {
	return $value == 't';
	}

	static function to_database_boolean($value) {
	return $value ? 't' : 'f';
	}

	static function to_js_time($time_str) {
	$timestamp_in_ms = strtotime($time_str) * 1000;
	$dot_index = strrpos($time_str, '.');
	if ($dot_index !== FALSE) {
	// Keep 5 decimal digits as postgres timestamp may only have 5 decimal digits.
	// Multiply by 1000 ahead to avoid losing precision. 1538041792.670479 will become 1538041792.6705 on php.
	$timestamp_in_ms += round(floatval(substr($time_str, $dot_index)), 5) * 1000;
	}
	return intval($timestamp_in_ms);
	}

	static function escape_for_like($string) {
	return str_replace(array('\\', '_', '%'), array('\\\\', '\\_', '\\%'), $string);
	}

	function connect() {
	$databaseConfig = config('database');

	$host = $databaseConfig['host'];
	$port = $databaseConfig['port'];
	$dbname = $databaseConfig['name'];
	$user = $databaseConfig['username'];
	$password = $databaseConfig['password'];
	$connectionString = "host=$host port=$port dbname=$dbname user=$user password=$password";

	$sslConfigString = '';

	if (array_get($databaseConfig, 'ssl')) {
	$sslConfig = $databaseConfig['ssl'];
	$sslConfigString .= ' sslmode=' . array_get($sslConfig, 'mode', 'require');
	foreach (array('rootcert', 'cert', 'key') as $key) {
	if (!array_get($sslConfig, $key))
	continue;

	$path = $sslConfig[$key];
	if (strlen($path) && $path[0] !== '/')
	$path = CONFIG_DIR . '/' . $path;

	$sslConfigString .= " ssl$key=$path";
	}
	}

	$connectionString .= $sslConfigString;
	$this->connection = @pg_connect($connectionString);
	return $this->connection ? true : false;
	}

	private function prefixed_column_names($columns, $prefix = NULL) {
	if (!$prefix \|\| !$columns)
	return join(', ', $columns);
	return $prefix . '_' . join(', ' . $prefix . '_', $columns);
	}

	private function prefixed_name($column, $prefix = NULL) {
	return $prefix ? $prefix . '_' . $column : $column;
	}

	private function prepare_params($params, &$placeholders, &$values, &$null_columns = NULL) {
	$column_names = array();

	$i = count($values) + 1;
	foreach (array_keys($params) as $name) {
	$current_value = $params[$name];
	if ($current_value === NULL && $null_columns !== NULL) {
	array_push($null_columns, $name);
	continue;
	}
	assert(ctype_alnum_underscore($name));
	array_push($column_names, $name);
	array_push($placeholders, '$' . $i);
	if (is_bool($current_value))
	$current_value = $this->to_database_boolean($current_value);
	array_push($values, $current_value);
	$i++;
	}

	return $column_names;
	}

	private function select_conditions_with_null_columns($prefix, $column_names, $placeholders, $null_columns) {
	$column_names = $this->prefixed_column_names($column_names, $prefix);
	$placeholders = join(', ', $placeholders);

	if (!$column_names && !$placeholders)
	$column_names = $placeholders = '1';
	$query = "($column_names) = ($placeholders)";
	foreach ($null_columns as $column_name)
	$query .= ' AND ' . $this->prefixed_name($column_name, $prefix) . ' IS NULL';
	return $query;
	}

	function insert_row($table, $prefix, $params, $returning = 'id') {
	$placeholders = array();
	$values = array();
	$column_names = $this->prepare_params($params, $placeholders, $values);

	assert(!$prefix \|\| ctype_alnum_underscore($prefix));
	$column_names = $this->prefixed_column_names($column_names, $prefix);
	$placeholders = join(', ', $placeholders);

	$value_query = $column_names ? "($column_names) VALUES ($placeholders)" : ' VALUES (default)';
	if ($returning) {
	$returning_column_name = $this->prefixed_name($returning, $prefix);
	$rows = $this->query_and_fetch_all("INSERT INTO $table $value_query RETURNING $returning_column_name", $values);
	return $rows ? $rows[0][$returning_column_name] : NULL;
	}

	return $this->query_and_get_affected_rows("INSERT INTO $table $value_query", $values) == 1;
	}

	function select_or_insert_row($table, $prefix, $select_params, $insert_params = NULL, $returning = 'id') {
	return $this->_select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, FALSE, TRUE);
	}

	function update_or_insert_row($table, $prefix, $select_params, $insert_params = NULL, $returning = 'id') {
	return $this->_select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, TRUE, TRUE);
	}

	function update_row($table, $prefix, $select_params, $update_params, $returning = 'id') {
	return $this->_select_update_or_insert_row($table, $prefix, $select_params, $update_params, $returning, TRUE, FALSE);
	}

	private function _select_update_or_insert_row($table, $prefix, $select_params, $insert_params, $returning, $should_update, $should_insert) {
	$values = array();

	$select_placeholders = array();
	$select_null_columns = array();
	$select_column_names = $this->prepare_params($select_params, $select_placeholders, $values, $select_null_columns);
	$select_values = array_slice($values, 0);

	if ($insert_params === NULL)
	$insert_params = $select_params;
	$insert_placeholders = array();
	$insert_column_names = $this->prepare_params($insert_params, $insert_placeholders, $values);

	assert(!!$returning);
	assert(!$prefix \|\| ctype_alnum_underscore($prefix));
	$returning_column_name = $returning == '' ? '' : $this->prefixed_name($returning, $prefix);

	$condition = $this->select_conditions_with_null_columns($prefix, $select_column_names, $select_placeholders, $select_null_columns);
	$query = "SELECT $returning_column_name FROM $table WHERE $condition";

	$insert_column_names = $this->prefixed_column_names($insert_column_names, $prefix);
	$insert_placeholders = join(', ', $insert_placeholders);

	// http://stackoverflow.com/questions/1109061/insert-on-duplicate-update-in-postgresql
	$rows = NULL;
	if ($should_update) {
	$rows = $this->query_and_fetch_all("UPDATE $table SET ($insert_column_names) = ($insert_placeholders)
	WHERE $condition RETURNING $returning_column_name", $values);
	}
	if (!$rows && $should_insert) {
	$rows = $this->query_and_fetch_all("INSERT INTO $table ($insert_column_names) SELECT $insert_placeholders
	WHERE NOT EXISTS ($query) RETURNING $returning_column_name", $values);
	}
	if (!$should_update && !$rows)
	$rows = $this->query_and_fetch_all($query, $select_values);

	return $rows ? ($returning == '*' ? $rows[0] : $rows[0][$returning_column_name]) : NULL;
	}

	function select_first_row($table, $prefix, $params, $order_by = NULL) {
	return $this->select_first_or_last_row($table, $prefix, $params, $order_by, FALSE);
	}

	function select_last_row($table, $prefix, $params, $order_by = NULL) {
	return $this->select_first_or_last_row($table, $prefix, $params, $order_by, TRUE);
	}

	private function select_first_or_last_row($table, $prefix, $params, $order_by, $descending_order) {
	$rows = $this->select_rows($table, $prefix, $params, $order_by, $descending_order, 0, 1);
	return $rows ? $rows[0] : NULL;
	}

	function select_rows($table, $prefix, $params,
	$order_by = NULL, $descending_order = FALSE, $offset = NULL, $limit = NULL) {

	$placeholders = array();
	$values = array();
	$null_columns = array();
	$column_names = $this->prepare_params($params, $placeholders, $values, $null_columns);
	$condition = $this->select_conditions_with_null_columns($prefix, $column_names, $placeholders, $null_columns);

	$query = "SELECT * FROM $table WHERE $condition";

	if ($order_by) {
	if (!is_array($order_by))
	$order_by = array($order_by);

	$order_columns = array();
	foreach ($order_by as $order_key) {
	assert(ctype_alnum_underscore($order_key));
	$order_column = $this->prefixed_name($order_key, $prefix) . ' ' . ($descending_order? 'DESC' : 'ASC');
	array_push($order_columns, $order_column);
	}
	$query .= ' ORDER BY ' . join(', ', $order_columns);
	}
	if ($offset !== NULL)
	$query .= ' OFFSET ' . intval($offset);
	if ($limit !== NULL)
	$query .= ' LIMIT ' . intval($limit);

	return $this->query_and_fetch_all($query, $values);
	}

	function query_and_get_affected_rows($query, $params = array()) {
	if (!$this->connection)
	return FALSE;
	$result = pg_query_params($this->connection, $query, $params);
	if (!$result)
	return FALSE;
	return pg_affected_rows($result);
	}

	function query_and_fetch_all($query, $params = array()) {
	if (!$this->connection)
	return NULL;
	$result = pg_query_params($this->connection, $query, $params);
	if (!$result)
	return NULL;
	if (pg_num_rows($result) == 0)
	return array();
	return pg_fetch_all($result);
	}

	function query($query, $params = array()) {
	if (!$this->connection)
	return FALSE;
	return pg_query_params($this->connection, $query, $params);
	}

	function fetch_next_row($result) {
	return pg_fetch_assoc($result);
	}

	function fetch_table($table_name, $column_to_be_ordered_by = null) {
	if (!$this->connection \|\| !ctype_alnum_underscore($table_name) \|\| ($column_to_be_ordered_by && !ctype_alnum_underscore($column_to_be_ordered_by)))
	return false;
	$clauses = '';
	if ($column_to_be_ordered_by)
	$clauses .= 'ORDER BY ' . $column_to_be_ordered_by;
	return $this->query_and_fetch_all("SELECT * FROM $table_name $clauses");
	}

	function begin_transaction() {
	return $this->connection and pg_query($this->connection, "BEGIN");
	}

	function commit_transaction() {
	return $this->connection and pg_query($this->connection, 'COMMIT');
	}

	function rollback_transaction() {
	return $this->connection and pg_query($this->connection, 'ROLLBACK');
	}

	}

	?>