public function update($name, $crit, $new_data)
{
if (!$this->lock_table($name, true)) {
return false;
}
$str_res = $this->locked_tables_list[$name];
extract($str_res);
$crit['col'] = '*';
$crit['offsets'] = true;
$crit['explain'] = false;
$crit['rtrim_strings'] = false;
$success = false;
$this->I->meta = $meta;
try {
$res = $this->select($name, $crit, $str_res);
if (isset($new_data[$aname]) && sizeof($res) > 1) {
throw new Exception('You cannot set new PRIMARY KEY value for more than one row at once.');
}
if ($res === false) {
break;
}
/* PHASE 0: Check that row update will not cause "Duplicate key errors" */
$need_unique_update = sizeof($unique) && sizeof(array_intersect($unique, array_keys($new_data)));
if ($need_unique_update && ($ufp = fopen_cached($this->dir . '/' . $name . '.btr', 'r+b'))) {
foreach ($unique as $unique_name) {
if (!isset($new_data[$unique_name])) {
continue;
}
/*
The conflict will be caused if:
- the row updated from the old value to the value that already exists
- if the update tries to set the same value for number of rows that exceed 1
*/
$srch = $this->I->search_unique($ufp, $new_data, $fields, $unique_name);
if (sizeof($res) > 1 || sizeof($res) == 1 && $res[0][$unique_name] != $new_data[$unique_name] && $srch !== false) {
throw new Exception('Duplicate key ' . $new_data[$unique_name] . ' for ' . $unique_name);
}
}
} else {
if ($need_unique_update && !$ufp) {
throw new Exception('Unique index file corrupt.');
}
}
/* PHASE 1: Check for primary index & insert new value if needed */
if (isset($new_data[$aname]) && ($pfp = fopen_cached($this->dir . '/' . $name . '.pri', 'r+b'))) {
$succ = true;
foreach ($res as $data) {
if (isset($new_data[$aname]) && $new_data[$aname] < $acnt && $new_data[$aname] != $data[$aname]) {
$cnt = $new_data[$aname];
fseek($pfp, 4 * $cnt);
list(, $offset) = unpack('l', fread($pfp, 4));
if ($offset < 0) {
fseek($pfp, 4 * $data[$aname], SEEK_SET);
list(, $newoff) = unpack('l', fread($pfp, 4));
fseek($pfp, -4, SEEK_CUR);
fputs($pfp, pack('l', -1));
fseek($pfp, 4 * $cnt, SEEK_SET);
fputs($pfp, pack('l', $newoff));
} else {
throw new Exception('Duplicate primary key value');
}
}
}
if (!$succ) {
break;
}
// either problem with delete_primary, delete_primary should already have set an error
} else {
if (isset($new_data[$aname])) {
throw new Exception('Primary index file corrupt.');
}
}
/* PHASE 2: Insert unique index values (it is safe to do now) */
//echo 'SUCC '.__LINE__.'<br>';
if ($need_unique_update) {
foreach ($unique as $unique_name) {
if (!isset($new_data[$unique_name])) {
continue;
}
foreach ($res as $data) {
if ($data[$unique_name] == $new_data[$unique_name]) {
continue;
}
$this->I->delete_unique($ufp, $data, $fields, $unique_name);
$this->I->insert_unique($ufp, $new_data, $fields, $unique_name, $data['__offset']);
}
}
}
/* PHASE 3: Insert index values */
//echo 'SUCC '.__LINE__.'<br>';
$need_index_update = sizeof($index) && sizeof(array_intersect($index, array_keys($new_data)));
if ($need_index_update && ($ifpi = fopen_cached($this->dir . '/' . $name . '.idx', 'r+b')) && ($ifp = fopen_cached($this->dir . '/' . $name . '.btr', 'r+b'))) {
foreach ($index as $index_name) {
if (!isset($new_data[$index_name])) {
continue;
}
foreach ($res as $data) {
if ($data[$index_name] == $new_data[$index_name]) {
continue;
}
// no need to update it :))
$this->I->delete_index($ifp, $ifpi, $data, $fields, $index_name, $data['__offset']);
$this->I->insert_index($ifp, $ifpi, $new_data, $fields, $index_name, $data['__offset']);
}
}
// echo 'FAIL '.__LINE__.'<br>';
} else {
if ($need_index_update && (!$ifpi || !$ifp)) {
throw new Exception('Index file corrupt.');
// echo 'FAIL '.__LINE__.'<br>';
}
}
/* LAST PHASE: Insert the data itself */
//echo 'SUCC '.__LINE__.'<br>';
if ($fp = fopen_cached($this->dir . '/' . $name . '.dat', 'r+b')) {
foreach ($res as $data_key => $data) {
$off = $data['__offset'];
fseek($fp, $off, SEEK_SET);
$ins = '';
//pack('x'); /* data for insertion to db */
$need_row_split = false;
foreach ($fields as $k => $v) {
@($od = $data[$k]);
$d = isset($new_data[$k]) ? $new_data[$k] : false;
// already checked for correctness of the operation
switch ($v) {
case 'BYTE':
$ins .= pack('c', $d !== false ? $d : $od);
break;
case 'INT':
$ins .= pack('l', $d !== false ? $d : $od);
break;
case 'TINYTEXT':
case 'TEXT':
case 'LONGTEXT':
$length = 'C';
if ($v == 'TEXT') {
$length = 'S';
}
if ($v == 'LONGTEXT') {
$length = 'l';
}
if ($d === false) {
$ins .= pack($length, strlen($od));
$ins .= $od;
} else {
if ($length == 'C' && strlen($d) > 255) {
$d = substr($d, 0, 255);
} else {
if ($length == 'S' && strlen($d) > 65535) {
$d = substr($d, 0, 65535);
} else {
if ($length == 'l' && strlen($d) > self::MAX_LEN) {
$d = substr($d, 0, self::MAX_LEN);
}
}
}
if (strlen($d) > strlen($od)) {
//$d = substr($d, 0, strlen($od));
$need_row_split = true;
}
if (strlen($d) < strlen($od)) {
$d .= str_repeat(' ', strlen($od) - strlen($d));
}
// should not add less, as it can lead to row corruption
$ins .= pack($length, strlen($d));
$ins .= $d;
}
break;
case 'DOUBLE':
$ins .= pack('d', $d !== false ? $d : $od);
break;
}
if ($d !== false) {
$res[$data_key][$k] = $d;
}
}
list(, $n) = unpack('c', fgetc($fp));
if ($n == self::ROW_NORMAL) {
if (!$need_row_split) {
//echo 'No need to split row<br>';
fwrite($fp, $ins, strlen($ins));
// 0 bytes written means an error too
} else {
//echo 'Need to split row<br>';
// first, determine initial length
fseek($fp, -1, SEEK_CUR);
$old_pos = ftell($fp);
$this->read_row($fields, $fp, $rtrim_strings = false);
$length = ftell($fp) - $old_pos - 1;
// 1 byte which indicates row state is not counted
// the point is that we do not want to do the split row operation often,
// so we leave some space (either 32 bytes or excess size),
// choosing the highest value
// length in the original row will be decreased by 8 bytes
// as we write OFFSET_NEXT_PART and ROW_LENGTH first and then data
$add_length = strlen($ins) - $length + 8;
$spare_length = max(32, strlen($ins) - $length);
// first, write the tail
fseek($fp, 0, SEEK_END);
$next_off = ftell($fp);
// write TYPE, OFFSET_OF_NEXT_PART = -1
fwrite($fp, pack('cll', self::ROW_CONTINUE, -1, $add_length + $spare_length));
// the thing is that actual data in the original row will become shorter
// by 8 bytes as we write OFFSET_NEXT_PART and ROW_LENGTH first and then data
fwrite($fp, substr($ins, $length - 8));
fwrite($fp, str_repeat(pack('x'), $spare_length));
// tail written, now rewrite original row
fseek($fp, $old_pos, SEEK_SET);
fwrite($fp, pack('cll', self::ROW_SPLIT, $next_off, $length - 8));
fwrite($fp, substr($ins, 0, $length - 8));
}
} else {
if ($n == self::ROW_SPLIT) {
// need_row_split is used only in case the field has not been split before
// because otherwise we have an easy way to determine overall length of the fragments
// and decide whether row split if really required
fseek($fp, -1, SEEK_CUR);
$old_off = ftell($fp);
//echo 'Row is split at offset '.$old_off.'<br>';
//echo 'Row contents: <pre>',!print_r($this->read_row(array_merge(array('__offset' => 'OFFSET'),$fields), $fp, false)),'</pre>';
fseek($fp, $old_off, SEEK_SET);
$chunks = array();
// ROW_OFFSET => ROW_LENGTH
$offset = $old_off;
while (true) {
//echo 'get row type from '.ftell($fp).'<br>';
list(, $n) = unpack('c', fgetc($fp));
list(, $next_offset, $row_length) = unpack('l2', fread($fp, 8));
$chunks[$offset] = $row_length;
if ($n != self::ROW_SPLIT && $n != self::ROW_CONTINUE) {
throw new Exception('Data file corrupt (invalid beginning of split row, expected ' . self::ROW_SPLIT . ' or ' . self::ROW_CONTINUE . ', got ' . $n . '). Please run repair table tools if present.');
}
if ($offset < 0 || fseek($fp, $next_offset) < 0) {
break;
}
$offset = $next_offset;
}
//echo 'chunks: <pre>',!print_r($chunks),'</pre>';
$chunks_offs = array_keys($chunks);
$chunks_len = array_sum($chunks);
if (strlen($ins) <= $chunks_len) {
$need_row_split = false;
} else {
$need_row_split = true;
}
if ($need_row_split) {
//echo 'Need to split row (with total of '.(sizeof($chunks) + 1).' chunks)<br>';
// adding new chunk
fseek($fp, 0, SEEK_END);
$offset = ftell($fp);
$chunks[$offset] = strlen($ins) - $chunks_len + max(32, strlen($ins) - $chunks_len);
$chunks_len += $chunks[$offset];
$chunks_offs[] = $offset;
}
// right padding initial string with zero bytes
// so that we can just use substr() to get data for chunks
if (strlen($ins) < $chunks_len) {
$ins .= str_repeat(pack('x'), $chunks_len - strlen($ins));
}
$spl = true;
// split or continue?
$str_j = 0;
// current position in data string
$str_i = 0;
// next chunk index
foreach ($chunks as $offset => $row_length) {
fseek($fp, $offset, SEEK_SET);
$next_off = -1;
$str_i++;
if (isset($chunks_offs[$str_i])) {
$next_off = $chunks_offs[$str_i];
}
fwrite($fp, pack('cll', $spl ? self::ROW_SPLIT : self::ROW_CONTINUE, $next_off, $row_length));
$spl = false;
fwrite($fp, substr($ins, $str_j, $row_length));
$str_j += $row_length;
}
// thanks for reading this rather short, but very exciting part :))
} else {
throw new Exception('Data file error (unknown row type).');
}
}
//
}
} else {
throw new Exception('Data table corrupt');
}
$success = true;
//echo 'SUCCESS';
} catch (Exception $e) {
$this->unlock_table($name);
throw $e;
}
if ($this->I->meta !== $meta) {
$meta = $this->I->meta;
rewind($str_fp);
ftruncate($str_fp, 0);
fwrite($str_fp, serialize(array($fields, $params, $meta)));
fflush($str_fp);
}
/*
$rollback = !$success; // roll changes to the files back?
foreach(explode(' ', 'pfp ifpi ifp ufp fp') as $v) if(isset($$v))
{
//if($rollback) rfrollback($$v);
//else rfcommit($$v);
fflush($$v);
}
*/
$this->unlock_table($name);
return $res;
}
function openTable_Index_ExactMatch($name, $columns, $col, $value)
{
static $uniqid = 0;
if (!$this->lock_table($name)) {
return false;
}
$type = false;
// types can be: self::INDEX_PRIMARY, self::INDEX_INDEX, self::INDEX_UNIQUE
$pointers = false;
// if one pointer, than it is just a value. Several pointers should be presented as cortege (an ordered list)
try {
if (!($fp = fopen_cached($this->dir . '/' . $name . '.dat', 'r+b'))) {
throw new Exception('Data file corrupt.');
}
extract($this->locked_tables_list[$name]);
if ($col == $aname) {
$type = self::INDEX_PRIMARY;
} else {
if (in_array($col, $index)) {
$type = self::INDEX_INDEX;
} else {
if (in_array($col, $unique)) {
$type = self::INDEX_UNIQUE;
} else {
throw new Exception('No index for column `' . $col . '`"');
}
}
}
$columns = $this->checkColumns($fields, $columns);
switch ($type) {
case self::INDEX_PRIMARY:
$pfp = fopen_cached($this->dir . '/' . $name . '.pri', 'r+b');
if (!$pfp) {
throw new Exception('Primary index corrupt');
}
$pointers = $pfp;
break;
case self::INDEX_UNIQUE:
$ufp = fopen_cached($this->dir . '/' . $name . '.btr', 'r+b');
if (!$ufp) {
throw new Exception('B-Tree index corrupt');
}
$pointers = $ufp;
break;
case self::INDEX_INDEX:
$ifp = fopen_cached($this->dir . '/' . $name . '.btr', 'r+b');
$ifpi = fopen_cached($this->dir . '/' . $name . '.idx', 'r+b');
if (!$ifp || !$ifpi) {
throw new Exception('Either B-Tree or List index is corrupt');
}
$pointers = array($ifp, $ifpi);
break;
default:
throw new Exception('Unknown index type (this error must never happen)');
break;
}
} catch (Exception $e) {
// should not close anything, as descriptors are cached (they are not cached in case of failure, so no need to worry about this either)
$this->unlock_table($name);
//return $this->set_error($err);
throw $e;
}
$uniqid++;
return array($name, $columns, $col, $value, $meta, $type, $pointers, $fp, $uniqid, $fields);
}
