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   1  <?php
   2  
   3  /*
   4   *  $Id: TailFilter.php 3076 2006-12-18 08:52:12Z fabien $  
   5   * 
   6   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   7   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   8   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   9   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  10   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  11   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  12   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  13   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  14   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  15   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  16   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  17   *
  18   * This software consists of voluntary contributions made by many individuals
  19   * and is licensed under the LGPL. For more information please see
  20   * <http://phing.info>.
  21  */
  22  
  23  require_once 'phing/filters/BaseParamFilterReader.php';
  24  
  25  /**
  26   * Reads the last <code>n</code> lines of a stream. (Default is last10 lines.)
  27   *
  28   * Example:
  29   *
  30   * <pre><tailfilter lines="3" /></pre>
  31   *
  32   * Or:
  33   *
  34   * <pre><filterreader classname="phing.filters.TailFilter">
  35   *   <param name="lines" value="3">
  36   * </filterreader></pre>
  37   *
  38   * @author    <a href="mailto:yl@seasonfive.com">Yannick Lecaillez</a>
  39   * @author    hans lellelid, hans@velum.net
  40   * @copyright © 2003 seasonfive. All rights reserved
  41   * @version   $Revision: 1.7 $
  42   * @see       BaseParamFilterReader
  43   * @package   phing.filters
  44   */
  45  class TailFilter extends BaseParamFilterReader implements ChainableReader {
  46  
  47      /**
  48       * Parameter name for the number of lines to be returned.
  49       * @var string
  50       */
  51      const LINES_KEY = "lines";
  52      
  53      
  54      /**
  55       * Number of lines to be returned in the filtered stream.
  56       * @var integer
  57       */ 
  58      private $_lines = 10;
  59      
  60      /**
  61       * Array to hold lines.
  62       * @var array
  63       */ 
  64      private    $_lineBuffer = array();
  65                  
  66      /**
  67       * Returns the last n lines of a file.
  68       * @param int $len Num chars to read.
  69       * @return mixed The filtered buffer or -1 if EOF.
  70       */
  71      function read($len = null) {
  72      
  73          while ( ($buffer = $this->in->read($len)) !== -1 ) {
  74              // Remove the last "\n" from buffer for
  75              // prevent explode to add an empty cell at
  76              // the end of array
  77              $buffer= trim($buffer, "\n");
  78              
  79              $lines = explode("\n", $buffer);
  80  
  81              if ( count($lines) >= $this->_lines ) {
  82                  // Buffer have more (or same) number of lines than needed.
  83                  // Fill lineBuffer with the last "$this->_lines" lasts ones.
  84                  $off = count($lines)-$this->_lines;
  85                  $this->_lineBuffer = array_slice($lines, $off);
  86              } else {
  87                  // Some new lines ...
  88                  // Prepare space for insert these new ones
  89                  $this->_lineBuffer = array_slice($this->_lineBuffer, count($lines)-1);
  90                  $this->_lineBuffer = array_merge($this->_lineBuffer, $lines);
  91              }
  92          }
  93  
  94          if ( empty($this->_lineBuffer) )
  95              $ret = -1;
  96          else {
  97              $ret = implode("\n", $this->_lineBuffer);
  98              $this->_lineBuffer = array();
  99          }
 100  
 101          return $ret;
 102      }
 103  
 104      /**
 105       * Sets the number of lines to be returned in the filtered stream.
 106       * 
 107       * @param integer $lines the number of lines to be returned in the filtered stream.
 108       */
 109      function setLines($lines) {
 110          $this->_lines = (int) $lines;
 111      }
 112  
 113      /**
 114       * Returns the number of lines to be returned in the filtered stream.
 115       * 
 116       * @return integer The number of lines to be returned in the filtered stream.
 117       */
 118      function getLines() {
 119          return $this->_lines;
 120      }
 121  
 122      /**
 123       * Creates a new TailFilter using the passed in
 124       * Reader for instantiation.
 125       * 
 126       * @param object A Reader object providing the underlying stream.
 127       *               Must not be <code>null</code>.
 128       * 
 129       * @return object A new filter based on this configuration, but filtering
 130       *         the specified reader.
 131       */
 132      function chain(Reader $reader) {
 133          $newFilter = new TailFilter($reader);
 134          $newFilter->setLines($this->getLines());
 135          $newFilter->setInitialized(true);
 136          $newFilter->setProject($this->getProject());        
 137          return $newFilter;
 138      }
 139  
 140      /**
 141       * Scans the parameters list for the "lines" parameter and uses
 142       * it to set the number of lines to be returned in the filtered stream.
 143       */
 144      private function _initialize() {
 145          $params = $this->getParameters();
 146          if ( $params !== null ) {
 147              for($i=0, $_i=count($params); $i < $_i; $i++) {
 148                  if ( self::LINES_KEY == $params[$i]->getName() ) {
 149                      $this->_lines = (int) $params[$i]->getValue();
 150                      break;
 151                  }
 152              }
 153          }
 154      }
 155  }
 156  
 157  ?>