loganalyzer/classes/logstreamdisk.class.php
2008-03-11 12:19:58 +01:00

285 lines
7.1 KiB
PHP

<?php
/*
*********************************************************************
* Copyright by Adiscon GmbH | 2008! *
* -> www.phplogcon.org <- *
* *
* Use this script at your own risk! *
* ----------------------------------------------------------------- *
* Some constants *
* *
* LogStreamDisk provides access to the data on disk. In the most
* cases this will be plain text files. If we need access to e.g.
* zipped files, this will be handled by a separate driver.
*
* \version 1.0.1 2nd Version
* \version 1.0.0 Init Version
* *
* All directives are explained within this file *
*********************************************************************
*/
// --- Avoid directly accessing this file!
if ( !defined('IN_PHPLOGCON') )
{
die('Hacking attempt');
exit;
}
// ---
class LogStreamDisk extends LogStream {
private $_currentOffset = -1;
private $_currentStartPos = -1;
private $_fp = null;
private $_bEOF = false;
const _BUFFER_LENGHT = 4096;
private $_buffer = false;
private $_buffer_lenght = -1;
private $_p_buffer = -1;
// cache for backwards reading
private $_cache_lines = null;
private $_p_cache_lines = -1;
// Constructor
public function LogStreamDisk($streamConfigObj) {
$this->_logStreamConfigObj = $streamConfigObj;
}
/**
* Open the file with read access.
*
* @param streamConfigObj object in: It has to be a LogSteamDiskConfig object.
* @param bStartAtEOF bool in: If set to true the file pointer is set at EOF.
* @return integer Error stat
*/
public function Open($arrProperties, $bStartAtEOF = false) {
if(!file_exists($this->_logStreamConfigObj->FileName)) {
return ERROR_FILE_NOT_FOUND;
}
$this->_fp = fopen($this->_logStreamConfigObj->FileName, 'r');
if ($bStartAtEOF) {
fseek($this->_fp, 0, SEEK_END);
}
$this->_currentOffset = ftell($this->_fp);
$this->_currentStartPos = $this->_currentOffset;
$this->_arrProperties = $arrProperties;
// init read
$this->ReadNextBlock();
return SUCCESS;
}
/**
* Close the file.
*
* @return integer Error state
*/
public function Close() {
if (!fclose($this->_fp)) {
return ERROR_FILE_CANT_CLOSE;
}
return SUCCESS;
}
public function ReadNextBlock() {
//echo 'in ReadNextBlock<br />';
$this->_buffer = fread($this->_fp, self::_BUFFER_LENGHT);
$this->_buffer_lenght = strlen($this->_buffer);
$this->_p_buffer = 0;
if ($this->_buffer == false)
return ERROR_FILE_BOF;
return SUCCESS;
}
/**
* Read the data from a specific uID which means in this
* case from a given offset of the file.
*
* @param uID integer in/out: unique id of the data row
* @param logLine string out: data row
* @return integer Error state
* @see ReadNext()
*/
public function Read($uID, &$logLine) {
fseek($this->_fp, $uI);
// with Read we can only read forwards.
// so we have to remember the current read
// direction
$tmp = $this->_readDirection;
$iRet = $this->ReadNext($uID, $logLine);
$this->_readDirection = $tmp;
return $iRet;
}
/**
* Read the next line from the file depending on the current
* read direction.
*
* Hint: If the current stream becomes unavailable an error
* stated is retuned. A typical case is if a log rotation
* changed the original data source.
*
* @param uID integer out: uID is the offset of data row
* @param logLine string out: data row
* @return integer Error state
* @see ReadNext
*/
public function ReadNext(&$uID, &$logLine) {
if ($this->_readDirection == EnumReadDirection::Forward) {
return $this->ReadNextForwards($uID, $logLine);
}
return $this->ReadNextBackwards($uID, $logLine);
}
private function ReadNextForwards(&$uID, &$logLine) {
if ($this->bEOF) {
return ERROR_FILE_EOF;
}
if (($this->_p_buffer == $this->_buffer_lenght) && ($this->ReadNextBlock() != SUCCESS)) {
return ERROR_UNDEFINED;
}
$line = '';
do {
$pos = -1;
if (($pos = strpos($this->_buffer, "\n", $this->_p_buffer)) !== false) {
$logLine = $line . substr($this->_buffer, $this->_p_buffer, $pos - $this->_p_buffer);
$this->_currentOffset = $pos - $this->_p_buffer + 1;
$this->_p_buffer = $pos + 1;
$uID = $this->_currentStartPos;
$this->_currentStartPos = $this->_currentOffset;
return SUCCESS;
}
$line .= substr($this->_buffer, $this->_p_buffer, $this->_buffer_lenght - $this->_p_buffer);
$this->_currentOffset += $this->_buffer_lenght - $this->_p_buffer;
} while ($this->ReadNextBlock() == SUCCESS);
return ERROR_UNDEFINED;
}
/*
private function ReadNextForwards(&$uID, &$logLine) {
if (feof($this->_fp)) {
return ERROR_FILE_EOF;
}
$uID = ftell($this->_fp);
$logLine = fgets($this->_fp);
if ($logLine === false) {
// ToDo: error occurs, or EOF
return 1;
}
$this->_currentOffset = $this->_currentOffset + sizeof($logLine);
return SUCCESS;
}
*/
private function ReadNextBackwards(&$uID, &$logLine) {
if ($this->_p_cache_lines < 0) {
if (($iRet = $this->InitCacheLines()) > 0) { // error or BOF?
return $iRet;
}
}
// at this stage we can read from cache
$uID = $this->_cache_lines[$this->_p_cache_lines][0];
$logLine = $this->_cache_lines[$this->_p_cache_lines][1];
$this->_p_cache_lines--;
return SUCCESS;
}
private function ClearCacheLines() {
unset($this->_cache_lines);
$this->_p_cache_lines = -1;
}
private function InitCacheLines() {
$orig_offset = ftell($this->_fp);
if ($this->_readDirection == EnumReadDirection::Backward) {
// if we have already used the cache take the last positon
// as offset and then clear the cache
if (isset($this->_cache_lines[0][0])) {
$orig_offset = $this->_cache_lines[0][0];
$this->ClearCacheLines();
// check if it is the first line so we have BOF
if ($orig_offset == 0) {
return ERROR_FILE_BOF;
}
}
}
$offset = $orig_offset - 4096;
if ($offset < 0) {
$offset = 0;
}
fseek($this->_fp, $offset);
if ($offset != 0) {
// we do not know if we are on the beginning of a line
// therefore we simply skip the first line
fgets($this->_fp);
}
while (($offset = ftell($this->_fp)) < $orig_offset) {
$this->_p_cache_lines++;
$this->_cache_lines[$this->_p_cache_lines][0] = $offset;
$this->_cache_lines[$this->_p_cache_lines][1] = fgets($this->_fp);
if ($this->_cache_lines[$this->_p_cache_line][1] === false) {
// probably EOF or an error
unset($this->_cache_lines[$this->_p_cache_line]);
$this->_p_cache_lines--;
break;
}
}
return SUCCESS;
}
/**
* Set the filter for the current stream.
*
* @param filter object in: filter object
* @return integer Error state
*/
public function SetFilter($filter) {
return SUCCESS;
}
/**
* Set the direction the stream should read data.
*
*
*
* @param enumReadDirectionfilter EnumReadDirection in: The new direction.
* @return integer Error state
*/
public function SetReadDirection($enumReadDirection) {
// only if the read direction change we have do do anything
if ($this->_readDirection == $enumReadDirection)
return SUCCESS;
$this->_readDirection = $enumReadDirection;
return SUCCESS;
}
}
?>