MediaWiki 1.16.0

[autoinstallsdev/mediawiki.git] / includes / Cdb.php

diff --git a/includes/Cdb.php b/includes/Cdb.php
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+++ b/includes/Cdb.php
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+<?php
+
+/**
+ * Read from a CDB file.
+ * Native and pure PHP implementations are provided.
+ * http://cr.yp.to/cdb.html
+ */
+abstract class CdbReader {
+       /**
+        * Open a file and return a subclass instance
+        */
+       public static function open( $fileName ) {
+               if ( self::haveExtension() ) {
+                       return new CdbReader_DBA( $fileName );
+               } else {
+                       wfDebug( "Warning: no dba extension found, using emulation.\n" );
+                       return new CdbReader_PHP( $fileName );
+               }
+       }
+
+       /**
+        * Returns true if the native extension is available
+        */
+       public static function haveExtension() {
+               if ( !function_exists( 'dba_handlers' ) ) {
+                       return false;
+               }
+               $handlers = dba_handlers();
+               if ( !in_array( 'cdb', $handlers ) || !in_array( 'cdb_make', $handlers ) ) {
+                       return false;
+               }
+               return true;
+       }
+
+       /**
+        * Construct the object and open the file
+        */
+       abstract function __construct( $fileName );
+
+       /**
+        * Close the file. Optional, you can just let the variable go out of scope.
+        */
+       abstract function close();
+
+       /**
+        * Get a value with a given key. Only string values are supported.
+        */
+       abstract public function get( $key );
+}
+
+/**
+ * Write to a CDB file.
+ * Native and pure PHP implementations are provided.
+ */
+abstract class CdbWriter {
+       /**
+        * Open a writer and return a subclass instance.
+        * The user must have write access to the directory, for temporary file creation.
+        */
+       public static function open( $fileName ) {
+               if ( CdbReader::haveExtension() ) {
+                       return new CdbWriter_DBA( $fileName );
+               } else {
+                       wfDebug( "Warning: no dba extension found, using emulation.\n" );
+                       return new CdbWriter_PHP( $fileName );
+               }
+       }
+
+       /**
+        * Create the object and open the file
+        */
+       abstract function __construct( $fileName );
+
+       /**
+        * Set a key to a given value. The value will be converted to string.
+        */
+       abstract public function set( $key, $value );
+
+       /**
+        * Close the writer object. You should call this function before the object
+        * goes out of scope, to write out the final hashtables.
+        */
+       abstract public function close();
+}
+
+
+/**
+ * Reader class which uses the DBA extension
+ */
+class CdbReader_DBA {
+       var $handle;
+
+       function __construct( $fileName ) {
+               $this->handle = dba_open( $fileName, 'r-', 'cdb' );
+               if ( !$this->handle ) {
+                       throw new MWException( 'Unable to open DB file "' . $fileName . '"' );
+               }
+       }
+
+       function close() {
+               if( isset($this->handle) )
+                       dba_close( $this->handle );
+               unset( $this->handle );
+       }
+
+       function get( $key ) {
+               return dba_fetch( $key, $this->handle );
+       }
+}
+
+
+/**
+ * Writer class which uses the DBA extension
+ */
+class CdbWriter_DBA {
+       var $handle, $realFileName, $tmpFileName;
+
+       function __construct( $fileName ) {
+               $this->realFileName = $fileName;
+               $this->tmpFileName = $fileName . '.tmp.' . mt_rand( 0, 0x7fffffff );
+               $this->handle = dba_open( $this->tmpFileName, 'n', 'cdb_make' );
+               if ( !$this->handle ) {
+                       throw new MWException( 'Unable to open DB file for write "' . $fileName . '"' );
+               }
+       }
+
+       function set( $key, $value ) {
+               return dba_insert( $key, $value, $this->handle );
+       }
+
+       function close() {
+               if( isset($this->handle) )
+                       dba_close( $this->handle );
+               if ( wfIsWindows() ) {
+                       unlink( $this->realFileName );
+               }
+               if ( !rename( $this->tmpFileName, $this->realFileName ) ) {
+                       throw new MWException( 'Unable to move the new CDB file into place.' );
+               }
+               unset( $this->handle );
+       }
+
+       function __destruct() {
+               if ( isset( $this->handle ) ) {
+                       $this->close();
+               }
+       }
+}
+