Merge branch 'master' of ssh://al@git.adiscon.com/git/phplogcon

classes/logstreamdisk.class.php

@@ -18,7 +18,18 @@ if ( !defined('IN_PHPLOGCON') )
 */
 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($streamConfigObj) {
@@ -29,16 +40,24 @@ class LogStreamDisk extends LogStream {
 	* Open the file with read access.
 	*
 	* @param streamConfigObj object in: It has to be a LogSteamDiskConfig object.
+	* @param bStartAtEOF bool in: If set to true the file pointer is set at EOF.
 	* @return integer Error stat
 	*/
-	public function Open($arrProperties) {
+	public function Open($arrProperties, $bStartAtEOF = false) {
 		if(!file_exists($this->_logStreamConfigObj->FileName)) {
 			return ERROR_FILE_NOT_FOUND;
 		}
-		
-		$this->_fp = fopen($this->_logStreamConfigObj->FileName, 'r');
-		$this->_currentOffset = 0;
+
+		$this->_fp = fopen($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;
 	}
 
@@ -55,7 +74,40 @@ class LogStreamDisk extends LogStream {
 		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 $iRet;
+	}
+
 	/**
 	* Read the next line from the file depending on the current
 	* read direction.
@@ -70,13 +122,51 @@ class LogStreamDisk extends LogStream {
 	* @see ReadNext
 	*/
 	public function ReadNext(&$uID, &$logLine) {
+		if ($this->_readDirection == EnumReadDirection::Forward) {
+			return $this->ReadNextForwards($uID, $logLine);
+		}
 
-		$uID = $this->_currentOffset;
+		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
@@ -85,30 +175,71 @@ class LogStreamDisk extends LogStream {
 		
 		$this->_currentOffset = $this->_currentOffset + sizeof($logLine);
 		
-		return 0;
+		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;
 	}
 
-	/**
-	* 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) {
-		$this->_currentOffset = $uID;
-		fseek($fp, $this->_currentOffset);
+	private function ClearCacheLines() {
+			unset($this->_cache_lines);
+			$this->_p_cache_lines = -1;
+	}
 
-		// 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;
+	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();
 
-		return $iRet;
+				// check if it is the first line so we have BOF
+				if ($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;
 	}
 
 	/**
@@ -118,17 +249,25 @@ class LogStreamDisk extends LogStream {
 	* @return integer Error state
 	*/
 	public function SetFilter($filter) {
-		return 0;	
+		return SUCCESS;	
 	}
 
 	/**
 	* Set the direction the stream should read data.
 	*
+	* 
+	*
 	* @param enumReadDirectionfilter EnumReadDirection in: The new direction.
 	* @return integer Error state
 	*/
 	public function SetReadDirection($enumReadDirection) {
-		return 0;
+		
+		// only if the read direction change we have do do anything
+		if ($this->_readDirection == $enumReadDirection)
+			return SUCCESS;
+
+		$this->_readDirection = $enumReadDirection;
+		return SUCCESS;
 	}
 }
 

include/constants_errors.php

@@ -2,5 +2,7 @@
 define('SUCCESS ', 0);
 define('ERROR_FILE_NOT_FOUND', 1);
 define('ERROR_FILE_CANT_CLOSE', 2);
-define('ERROR_FILE_EOF', 2);
+define('ERROR_FILE_EOF', 3);
+define('ERROR_FILE_BOF', 4);
+define('ERROR_UNDEFINED', 5);
 ?>