<?php
/**
 * Copy all files in some containers of one backend to another.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Maintenance
 */

require_once( dirname( __FILE__ ) . '/Maintenance.php' );

/**
 * Copy all files in one container of one backend to another.
 *
 * This can also be used to re-shard the files for one backend using the
 * config of second backend. The second backend should have the same config
 * as the first, except for it having a different name and different sharding
 * configuration. The backend should be made read-only while this runs.
 * After this script finishes, the old files in the containers can be deleted.
 *
 * @ingroup Maintenance
 */
class CopyFileBackend extends Maintenance {
	public function __construct() {
		parent::__construct();
		$this->mDescription = "Copy files in one backend to another.";
		$this->addOption( 'src', 'Backend containing the source files', true, true );
		$this->addOption( 'dst', 'Backend where files should be copied to', true, true );
		$this->addOption( 'containers', 'Pipe separated list of containers', true, true );
		$this->addOption( 'subdir', 'Only do items in this child directory', false, true );
		$this->setBatchSize( 50 );
	}

	public function execute() {
		$src = FileBackendGroup::singleton()->get( $this->getOption( 'src' ) );
		$dst = FileBackendGroup::singleton()->get( $this->getOption( 'dst' ) );
		$containers = explode( '|', $this->getOption( 'containers' ) );
		$subDir = $this->getOption( rtrim( 'subdir', '/' ), '' );

		$count = 0;
		foreach ( $containers as $container ) {
			if ( $subDir != '' ) {
				$backendRel = "$container/$subDir";
				$this->output( "Doing container '$container', directory '$subDir'...\n" );
			} else {
				$backendRel = $container;
				$this->output( "Doing container '$container'...\n" );
			}

			$dir = $src->getRootStoragePath() . "/$backendRel";
			$srcPathsRel = $src->getFileList( array( 'dir' => $dir ) );
			if ( $srcPathsRel === null ) {
				$this->error( "Could not list files in $container.", 1 ); // die
			}

			$batchPaths = array();
			foreach ( $srcPathsRel as $srcPathRel ) {
				$batchPaths[$srcPathRel] = 1; // remove duplicates
				if ( count( $batchPaths ) >= $this->mBatchSize ) {
					$this->copyFileBatch( array_keys( $batchPaths ), $backendRel, $src, $dst );
					$batchPaths = array(); // done
				}
				++$count;
			}
			if ( count( $batchPaths ) ) { // left-overs
				$this->copyFileBatch( array_keys( $batchPaths ), $backendRel, $src, $dst );
				$batchPaths = array(); // done
			}

			if ( $subDir != '' ) {
				$this->output( "Finished container '$container', directory '$subDir'.\n" );
			} else {
				$this->output( "Finished container '$container'.\n" );
			}
		}

		$this->output( "Done [$count file(s)].\n" );
	}

	protected function copyFileBatch(
		array $srcPathsRel, $backendRel, FileBackend $src, FileBackend $dst
	) {
		$ops = array();
		$fsFiles = array();
		foreach ( $srcPathsRel as $srcPathRel ) {
			$srcPath = $src->getRootStoragePath() . "/$backendRel/$srcPathRel";
			$dstPath = $dst->getRootStoragePath() . "/$backendRel/$srcPathRel";
			if ( $this->filesAreSame( $src, $dst, $srcPath, $dstPath ) ) {
				$this->output( "Already have $srcPathRel.\n" );
				continue; // assume already copied...
			}
			// Note: getLocalReference() is fast for FS backends
			$fsFile = $src->getLocalReference( array( 'src' => $srcPath, 'latest' => 1 ) );
			if ( !$fsFile ) {
				$this->error( "Could not get local copy of $srcPath.", 1 ); // die
			}
			$fsFiles[] = $fsFile; // keep TempFSFile objects alive as needed
			// Note: prepare() is usually fast for key/value backends
			$status = $dst->prepare( array( 'dir' => dirname( $dstPath ) ) );
			if ( !$status->isOK() ) {
				$this->error( print_r( $status->getErrorsArray(), true ) );
				$this->error( "Could not copy $srcPath to $dstPath.", 1 ); // die
			}
			$ops[] = array( 'op' => 'store',
				'src' => $fsFile->getPath(), 'dst' => $dstPath, 'overwrite' => 1 );
		}

		$status = $dst->doOperations( $ops, array( 'nonJournaled' => 1 ) );
		if ( !$status->isOK() ) {
			$this->error( print_r( $status->getErrorsArray(), true ) );
			$this->error( "Could not copy file batch.", 1 ); // die
		} else {
			$this->output( "Copied these file(s):\n" . implode( "\n", $srcPathsRel ) . "\n\n" );
		}
	}

	protected function filesAreSame( FileBackend $src, FileBackend $dst, $sPath, $dPath ) {
		return (
			( $src->fileExists( array( 'src' => $sPath, 'latest' => 1 ) )
				=== $dst->fileExists( array( 'src' => $dPath, 'latest' => 1 ) ) // short-circuit
			) && ( $src->getFileSize( array( 'src' => $sPath, 'latest' => 1 ) )
				=== $dst->getFileSize( array( 'src' => $dPath, 'latest' => 1 ) ) // short-circuit
			) && ( $src->getFileSha1Base36( array( 'src' => $sPath, 'latest' => 1 ) )
				=== $dst->getFileSha1Base36( array( 'src' => $dPath, 'latest' => 1 ) )
			)
		);
	}
}

$maintClass = 'CopyFileBackend';
require_once( RUN_MAINTENANCE_IF_MAIN );