1 files changed, 149 insertions, 0 deletions
diff --git a/includes/Cdb.php b/includes/Cdb.php
new file mode 100644
index 00000000..ab429872
--- /dev/null
+++ b/includes/Cdb.php
@@ -0,0 +1,149 @@
+<?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();
+		}
+	}
+}
+