/**
* Open metatable file
* @param string
* @param int defaults to self::READWRITE | self::STRINGS_GC
* @return metatable|bool
*/
public static function open($filename, $flags = 6)
{
// check flags
if (($flags & self::READONLY) === self::READONLY && ($flags & self::READWRITE) === self::READWRITE) {
return FALSE;
}
// initialize
$tries_left = self::LOCK_TRIES;
$inode = @fileinode($filename);
$handle = @fopen($filename, 'rb' . (($flags & self::READWRITE) === self::READWRITE ? '+' : ''));
$locking = NULL;
$tmp = NULL;
$structure = array();
$handle_filename = NULL;
$tmp_filename = NULL;
// open metatable file
if ($handle) {
// file exists
while (true) {
// try to lock
if (!flock($handle, ($flags & self::READONLY) === self::READONLY ? LOCK_SH : LOCK_EX)) {
fclose($handle);
return FALSE;
}
// check inode
clearstatcache();
$current_inode = fileinode($filename);
if ($current_inode === $inode) {
break;
}
if ($tries_left <= 0) {
fclose($handle);
return FALSE;
}
// try to open again
fclose($handle);
$tries_left--;
$inode = $current_inode;
$handle = @fopen($filename, 'rb' . (($flags & self::READWRITE) === self::READWRITE ? '+' : ''));
if (!$handle) {
return FALSE;
}
}
} else {
// file does not exist
if (($flags & self::READONLY) === self::READONLY) {
return FALSE;
}
$handle = NULL;
}
// read structure
$structure = array('signature' => self::MAGIC_STRING, 'version' => self::VERSION, 'frames' => array(), 'frames_indexes' => array());
$frames = array();
if ($handle) {
$structure = self::structure_read($handle);
}
// open write and temporary file
if (($flags & self::READWRITE) === self::READWRITE) {
$locking = $handle;
list($tmp_filename, $tmp) = self::tmp();
if (!$tmp_filename || !$tmp) {
if ($locking) {
fclose($locking);
}
return FALSE;
}
list($handle_filename, $handle) = array($filename . '~handle', @fopen($filename . '~handle', 'w+'));
if (!$handle_filename || !$handle) {
fclose($tmp);
unlink($tmp_filename);
if ($locking) {
fclose($locking);
}
return FALSE;
}
// copy data to temporary
if ($locking) {
foreach ($structure['frames'] as $i => $frame) {
if ($frame['name'] === self::FRAME_STRINGS) {
$structure['frames'][$i]['used_at_start'] = $structure['frames'][$i]['used'];
$structure['frames'][$i]['offset_at_start'] = $structure['frames'][$i]['offset'];
}
if (!(($flags & self::STRINGS_GC) === self::STRINGS_GC && $frame['name'] === self::FRAME_STRINGS)) {
if (!(fseek($locking, $frame['offset'], SEEK_SET) !== -1 && fseek($handle, $frame['offset'], SEEK_SET) !== -1 && stream_copy_to_stream($locking, $handle, $frame['used']) === $frame['used'])) {
fclose($locking);
fclose($handle);
unlink($handle_filename);
fclose($tmp);
unlink($tmp_filename);
return FALSE;
}
}
}
}
}
// create instance
$that = new self();
$that->flags = $flags;
$that->filename = $filename;
$that->handle_filename = $handle_filename;
$that->tmp_filename = $tmp_filename;
$that->locking = $locking;
$that->handle = $handle;
$that->tmp = $tmp;
$that->structure = $structure;
if (!isset($structure['frames_indexes'][self::FRAME_INDEXES])) {
$that->frame_create(self::FRAME_INDEXES, 0);
}
if (!isset($structure['frames_indexes'][self::FRAME_STRINGS])) {
$that->frame_create(self::FRAME_STRINGS, 1);
}
if (!isset($structure['frames_indexes'][self::FRAME_DATA])) {
$that->frame_create(self::FRAME_DATA, 2);
}
// get indexes
fseek($that->handle, $that->structure['frames'][$that->structure['frames_indexes'][self::FRAME_INDEXES]]['offset'], SEEK_SET);
for ($i = 0, $N = $that->structure['frames'][$that->structure['frames_indexes'][self::FRAME_INDEXES]]['used'] / self::SIZEOF_INDEX_RECORD; $i < $N; $i++) {
$data = fread($that->handle, self::SIZEOF_INDEX_RECORD);
if (strlen($data) < self::SIZEOF_INDEX_RECORD) {
continue;
}
$data = unpack(self::INDEX_RECORD_UNPACK, $data);
$that->indexes[$data['start']] = array($data['lower'], $data['upper']);
}
// return
return $that;
}
