} else {
$dstStat = $dst->getFileStat( array( 'src' => $dPath ) );
}
- return (
+ // Initial fast checks to see if files are obviously different
+ $sameFast = (
is_array( $srcStat ) // sanity check that source exists
&& is_array( $dstStat ) // dest exists
&& $srcStat['size'] === $dstStat['size']
- && ( !$skipHash || $srcStat['mtime'] <= $dstStat['mtime'] )
- && ( $skipHash || $src->getFileSha1Base36( array( 'src' => $sPath, 'latest' => 1 ) )
- === $dst->getFileSha1Base36( array( 'src' => $dPath, 'latest' => 1 ) )
- )
);
+ // More thorough checks against files
+ if ( !$sameFast ) {
+ $same = false; // no need to look farther
+ } elseif ( isset( $srcStat['md5'] ) && isset( $dstStat['md5'] ) ) {
+ // If MD5 was already in the stat info, just use it.
+ // This is useful as many objects stores can return this in object listing,
+ // so we can use it to avoid slow per-file HEADs.
+ $same = ( $srcStat['md5'] === $dstStat['md5'] );
+ } elseif ( $skipHash ) {
+ // This mode is good for copying to a backup location or resyncing clone
+ // backends in FileBackendMultiWrite (since they get writes second, they have
+ // higher timestamps). However, when copying the other way, this hits loads of
+ // false positives (possibly 100%) and wastes a bunch of time on GETs/PUTs.
+ $same = ( $srcStat['mtime'] <= $dstStat['mtime'] );
+ } else {
+ // This is the slowest method which does many per-file HEADs (unless an object
+ // store tracks SHA-1 in listings).
+ $same = ( $src->getFileSha1Base36( array( 'src' => $sPath, 'latest' => 1 ) )
+ === $dst->getFileSha1Base36( array( 'src' => $dPath, 'latest' => 1 ) ) );
+ }
+ return $same;
}
}