<?php
/**
 * Library for CSV serialization.
 *
 * This is used by the csv/proxy driver and is the CacheExecute()
 * serialization format.
 *
 * This file is part of ADOdb, a Database Abstraction Layer library for PHP.
 *
 * @package ADOdb
 * @link https://adodb.org Project's web site and documentation
 * @link https://github.com/ADOdb/ADOdb Source code and issue tracker
 *
 * The ADOdb Library is dual-licensed, released under both the BSD 3-Clause
 * and the GNU Lesser General Public Licence (LGPL) v2.1 or, at your option,
 * any later version. This means you can use it in proprietary products.
 * See the LICENSE.md file distributed with this source code for details.
 * @license BSD-3-Clause
 * @license LGPL-2.1-or-later
 *
 * @copyright 2000-2013 John Lim
 * @copyright 2014 Damien Regad, Mark Newnham and the ADOdb community
 */

// security - hide paths
if (!defined('ADODB_DIR')) die();

global $ADODB_INCLUDED_CSV;
$ADODB_INCLUDED_CSV = 1;

	/**
 	 * Convert a recordset into special format
	 *
	 * @param ADORecordSet  $rs the recordset
	 * @param ADOConnection $conn
	 * @param string        $sql
	 *
	 * @return string the CSV formatted data
	 */
	function _rs2serialize(&$rs,$conn=false,$sql='')
	{
		$max = ($rs) ? $rs->FieldCount() : 0;

		if ($sql) $sql = urlencode($sql);
		// metadata setup

		if ($max <= 0 || $rs->dataProvider == 'empty') { // is insert/update/delete
			if (is_object($conn)) {
				$sql .= ','.$conn->Affected_Rows();
				$sql .= ','.$conn->Insert_ID();
			} else
				$sql .= ',,';

			$text = "====-1,0,$sql\n";
			return $text;
		}
		$tt = ($rs->timeCreated) ? $rs->timeCreated : time();

		## changed format from ====0 to ====1
		$line = "====1,$tt,$sql\n";

		if ($rs->databaseType == 'array') {
			$rows = $rs->_array;
		} else {
			$rows = array();
			while (!$rs->EOF) {
				$rows[] = $rs->fields;
				$rs->MoveNext();
			}
		}

		for($i=0; $i < $max; $i++) {
			$o = $rs->FetchField($i);
			$flds[] = $o;
		}

		$savefetch = isset($rs->adodbFetchMode) ? $rs->adodbFetchMode : $rs->fetchMode;
		$class = $rs->connection->arrayClass;
		/** @var ADORecordSet $rs2 */
		$rs2 = new $class(ADORecordSet::DUMMY_QUERY_ID);
		$rs2->timeCreated = $rs->timeCreated; # memcache fix
		$rs2->sql = $rs->sql;
		$rs2->InitArrayFields($rows,$flds);
		$rs2->fetchMode = $savefetch;
		return $line.serialize($rs2);
	}

	/**
	 * Open CSV file and convert it into Data.
	 *
	 * @param string $url     file/ftp/http url
	 * @param string &$err    returns the error message
	 * @param int $timeout    dispose if recordset has been alive for $timeout secs
	 * @param string $rsclass RecordSet class to return
	 *
	 * @return ADORecordSet|false recordset, or false if error occurred.
	 *                            If no error occurred in sql INSERT/UPDATE/DELETE,
	 *                            empty recordset is returned.
	 */
	function csv2rs($url, &$err, $timeout=0, $rsclass='ADORecordSet_array')
	{
		$false = false;
		$err = false;
		$fp = @fopen($url,'rb');
		if (!$fp) {
			$err = $url.' file/URL not found';
			return $false;
		}
		@flock($fp, LOCK_SH);
		$arr = array();
		$ttl = 0;

		if ($meta = fgetcsv($fp, 32000, ",")) {
			// check if error message
			if (strncmp($meta[0],'****',4) === 0) {
				$err = trim(substr($meta[0],4,1024));
				fclose($fp);
				return $false;
			}
			// check for meta data
			// $meta[0] is -1 means return an empty recordset
			// $meta[1] contains a time

			if (strncmp($meta[0], '====',4) === 0) {

				if ($meta[0] == "====-1") {
					if (sizeof($meta) < 5) {
						$err = "Corrupt first line for format -1";
						fclose($fp);
						return $false;
					}
					fclose($fp);

					if ($timeout > 0) {
						$err = " Illegal Timeout $timeout ";
						return $false;
					}

					$rs = new $rsclass($val=true);
					$rs->fields = array();
					$rs->timeCreated = $meta[1];
					$rs->EOF = true;
					$rs->_numOfFields = 0;
					$rs->sql = urldecode($meta[2]);
					$rs->affectedrows = (integer)$meta[3];
					$rs->insertid = $meta[4];
					return $rs;
				}
			# Under high volume loads, we want only 1 thread/process to _write_file
			# so that we don't have 50 processes queueing to write the same data.
			# We use probabilistic timeout, ahead of time.
			#
			# -4 sec before timeout, give processes 1/32 chance of timing out
			# -2 sec before timeout, give processes 1/16 chance of timing out
			# -1 sec after timeout give processes 1/4 chance of timing out
			# +0 sec after timeout, give processes 100% chance of timing out
				if (sizeof($meta) > 1) {
					if($timeout >0){
						$tdiff = (integer)( $meta[1]+$timeout - time());
						if ($tdiff <= 2) {
							switch($tdiff) {
							case 4:
							case 3:
								if ((rand() & 31) == 0) {
									fclose($fp);
									$err = "Timeout 3";
									return $false;
								}
								break;
							case 2:
								if ((rand() & 15) == 0) {
									fclose($fp);
									$err = "Timeout 2";
									return $false;
								}
								break;
							case 1:
								if ((rand() & 3) == 0) {
									fclose($fp);
									$err = "Timeout 1";
									return $false;
								}
								break;
							default:
								fclose($fp);
								$err = "Timeout 0";
								return $false;
							} // switch

						} // if check flush cache
					}// (timeout>0)
					$ttl = $meta[1];
				}
				//================================================
				// new cache format - use serialize extensively...
				if ($meta[0] === '====1') {
					// slurp in the data
					$MAXSIZE = 128000;

					$text = fread($fp,$MAXSIZE);
					if (strlen($text)) {
						while ($txt = fread($fp,$MAXSIZE)) {
							$text .= $txt;
						}
					}
					fclose($fp);
					$rs = unserialize($text);
					if (is_object($rs)) $rs->timeCreated = $ttl;
					else {
						$err = "Unable to unserialize recordset";
						//echo htmlspecialchars($text),' !--END--!<p>';
					}
					return $rs;
				}

				$meta = false;
				$meta = fgetcsv($fp, 32000, ",");
				if (!$meta) {
					fclose($fp);
					$err = "Unexpected EOF 1";
					return $false;
				}
			}

			// Get Column definitions
			$flds = array();
			foreach($meta as $o) {
				$o2 = explode(':',$o);
				if (sizeof($o2)!=3) {
					$arr[] = $meta;
					$flds = false;
					break;
				}
				$fld = new ADOFieldObject();
				$fld->name = urldecode($o2[0]);
				$fld->type = $o2[1];
				$fld->max_length = $o2[2];
				$flds[] = $fld;
			}
		} else {
			fclose($fp);
			$err = "Recordset had unexpected EOF 2";
			return $false;
		}

		// slurp in the data
		$MAXSIZE = 128000;

		$text = '';
		while ($txt = fread($fp,$MAXSIZE)) {
			$text .= $txt;
		}

		fclose($fp);
		@$arr = unserialize($text);
		if (!is_array($arr)) {
			$err = "Recordset had unexpected EOF (in serialized recordset)";
			return $false;
		}
		$rs = new $rsclass();
		$rs->timeCreated = $ttl;
		$rs->InitArrayFields($arr,$flds);
		return $rs;
	}


	/**
	* Save a file $filename and its $contents (normally for caching) with file locking
	* Returns true if ok, false if fopen/fwrite error, 0 if rename error (eg. file is locked)
	*/
	function adodb_write_file($filename, $contents,$debug=false)
	{
	# https://www.php.net/bugs.php?id=9203 Bug that flock fails on Windows
	# So to simulate locking, we assume that rename is an atomic operation.
	# First we delete $filename, then we create a $tempfile write to it and
	# rename to the desired $filename. If the rename works, then we successfully
	# modified the file exclusively.
	# What a stupid need - having to simulate locking.
	# Risks:
	# 1. $tempfile name is not unique -- very very low
	# 2. unlink($filename) fails -- ok, rename will fail
	# 3. adodb reads stale file because unlink fails -- ok, $rs timeout occurs
	# 4. another process creates $filename between unlink() and rename() -- ok, rename() fails and  cache updated
		if (strncmp(PHP_OS,'WIN',3) === 0) {
			// skip the decimal place
			$mtime = substr(str_replace(' ','_',microtime()),2);
			// getmypid() actually returns 0 on Win98 - never mind!
			$tmpname = $filename.uniqid($mtime).getmypid();
			if (!($fd = @fopen($tmpname,'w'))) return false;
			if (fwrite($fd,$contents)) $ok = true;
			else $ok = false;
			fclose($fd);

			if ($ok) {
				@chmod($tmpname,0644);
				// the tricky moment
				@unlink($filename);
				if (!@rename($tmpname,$filename)) {
					@unlink($tmpname);
					$ok = 0;
				}
				if (!$ok) {
					if ($debug) ADOConnection::outp( " Rename $tmpname ".($ok? 'ok' : 'failed'));
				}
			}
			return $ok;
		}
		if (!($fd = @fopen($filename, 'a'))) return false;
		if (flock($fd, LOCK_EX) && ftruncate($fd, 0)) {
			if (fwrite( $fd, $contents )) $ok = true;
			else $ok = false;
			fclose($fd);
			@chmod($filename,0644);
		}else {
			fclose($fd);
			if ($debug)ADOConnection::outp( " Failed acquiring lock for $filename<br>\n");
			$ok = false;
		}

		return $ok;
	}
