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<?php
namespace dokuwiki\ChangeLog;
/**
* methods for handling of changelog of pages or media files
*/
abstract class ChangeLog
{
/** @var string */
protected $id;
/** @var int */
protected $chunk_size;
/** @var array */
protected $cache;
/**
* Constructor
*
* @param string $id page id
* @param int $chunk_size maximum block size read from file
*/
public function __construct($id, $chunk_size = 8192)
{
global $cache_revinfo;
$this->cache =& $cache_revinfo;
if (!isset($this->cache[$id])) {
$this->cache[$id] = array();
}
$this->id = $id;
$this->setChunkSize($chunk_size);
}
/**
* Set chunk size for file reading
* Chunk size zero let read whole file at once
*
* @param int $chunk_size maximum block size read from file
*/
public function setChunkSize($chunk_size)
{
if (!is_numeric($chunk_size)) $chunk_size = 0;
$this->chunk_size = (int)max($chunk_size, 0);
}
/**
* Returns path to changelog
*
* @return string path to file
*/
abstract protected function getChangelogFilename();
/**
* Returns path to current page/media
*
* @return string path to file
*/
abstract protected function getFilename();
/**
* Get the changelog information for a specific page id and revision (timestamp)
*
* Adjacent changelog lines are optimistically parsed and cached to speed up
* consecutive calls to getRevisionInfo. For large changelog files, only the chunk
* containing the requested changelog line is read.
*
* @param int $rev revision timestamp
* @return bool|array false or array with entries:
* - date: unix timestamp
* - ip: IPv4 address (127.0.0.1)
* - type: log line type
* - id: page id
* - user: user name
* - sum: edit summary (or action reason)
* - extra: extra data (varies by line type)
*
* @author Ben Coburn <btcoburn@silicodon.net>
* @author Kate Arzamastseva <pshns@ukr.net>
*/
public function getRevisionInfo($rev)
{
$rev = max($rev, 0);
// check if it's already in the memory cache
if (isset($this->cache[$this->id]) && isset($this->cache[$this->id][$rev])) {
return $this->cache[$this->id][$rev];
}
//read lines from changelog
list($fp, $lines) = $this->readloglines($rev);
if ($fp) {
fclose($fp);
}
if (empty($lines)) return false;
// parse and cache changelog lines
foreach ($lines as $value) {
$tmp = parseChangelogLine($value);
if ($tmp !== false) {
$this->cache[$this->id][$tmp['date']] = $tmp;
}
}
if (!isset($this->cache[$this->id][$rev])) {
return false;
}
return $this->cache[$this->id][$rev];
}
/**
* Return a list of page revisions numbers
*
* Does not guarantee that the revision exists in the attic,
* only that a line with the date exists in the changelog.
* By default the current revision is skipped.
*
* The current revision is automatically skipped when the page exists.
* See $INFO['meta']['last_change'] for the current revision.
* A negative $first let read the current revision too.
*
* For efficiency, the log lines are parsed and cached for later
* calls to getRevisionInfo. Large changelog files are read
* backwards in chunks until the requested number of changelog
* lines are recieved.
*
* @param int $first skip the first n changelog lines
* @param int $num number of revisions to return
* @return array with the revision timestamps
*
* @author Ben Coburn <btcoburn@silicodon.net>
* @author Kate Arzamastseva <pshns@ukr.net>
*/
public function getRevisions($first, $num)
{
$revs = array();
$lines = array();
$count = 0;
$num = max($num, 0);
if ($num == 0) {
return $revs;
}
if ($first < 0) {
$first = 0;
} else {
if (file_exists($this->getFilename())) {
// skip current revision if the page exists
$first = max($first + 1, 0);
}
}
$file = $this->getChangelogFilename();
if (!file_exists($file)) {
return $revs;
}
if (filesize($file) < $this->chunk_size || $this->chunk_size == 0) {
// read whole file
$lines = file($file);
if ($lines === false) {
return $revs;
}
} else {
// read chunks backwards
$fp = fopen($file, 'rb'); // "file pointer"
if ($fp === false) {
return $revs;
}
fseek($fp, 0, SEEK_END);
$tail = ftell($fp);
// chunk backwards
$finger = max($tail - $this->chunk_size, 0);
while ($count < $num + $first) {
$nl = $this->getNewlinepointer($fp, $finger);
// was the chunk big enough? if not, take another bite
if ($nl > 0 && $tail <= $nl) {
$finger = max($finger - $this->chunk_size, 0);
continue;
} else {
$finger = $nl;
}
// read chunk
$chunk = '';
$read_size = max($tail - $finger, 0); // found chunk size
$got = 0;
while ($got < $read_size && !feof($fp)) {
$tmp = @fread($fp, max(min($this->chunk_size, $read_size - $got), 0));
if ($tmp === false) {
break;
} //error state
$got += strlen($tmp);
$chunk .= $tmp;
}
$tmp = explode("\n", $chunk);
array_pop($tmp); // remove trailing newline
// combine with previous chunk
$count += count($tmp);
$lines = array_merge($tmp, $lines);
// next chunk
if ($finger == 0) {
break;
} else { // already read all the lines
$tail = $finger;
$finger = max($tail - $this->chunk_size, 0);
}
}
fclose($fp);
}
// skip parsing extra lines
$num = max(min(count($lines) - $first, $num), 0);
if ($first > 0 && $num > 0) {
$lines = array_slice($lines, max(count($lines) - $first - $num, 0), $num);
} else {
if ($first > 0 && $num == 0) {
$lines = array_slice($lines, 0, max(count($lines) - $first, 0));
} elseif ($first == 0 && $num > 0) {
$lines = array_slice($lines, max(count($lines) - $num, 0));
}
}
// handle lines in reverse order
for ($i = count($lines) - 1; $i >= 0; $i--) {
$tmp = parseChangelogLine($lines[$i]);
if ($tmp !== false) {
$this->cache[$this->id][$tmp['date']] = $tmp;
$revs[] = $tmp['date'];
}
}
return $revs;
}
/**
* Get the nth revision left or right handside for a specific page id and revision (timestamp)
*
* For large changelog files, only the chunk containing the
* reference revision $rev is read and sometimes a next chunck.
*
* Adjacent changelog lines are optimistically parsed and cached to speed up
* consecutive calls to getRevisionInfo.
*
* @param int $rev revision timestamp used as startdate (doesn't need to be revisionnumber)
* @param int $direction give position of returned revision with respect to $rev; positive=next, negative=prev
* @return bool|int
* timestamp of the requested revision
* otherwise false
*/
public function getRelativeRevision($rev, $direction)
{
$rev = max($rev, 0);
$direction = (int)$direction;
//no direction given or last rev, so no follow-up
if (!$direction || ($direction > 0 && $this->isCurrentRevision($rev))) {
return false;
}
//get lines from changelog
list($fp, $lines, $head, $tail, $eof) = $this->readloglines($rev);
if (empty($lines)) return false;
// look for revisions later/earlier then $rev, when founded count till the wanted revision is reached
// also parse and cache changelog lines for getRevisionInfo().
$revcounter = 0;
$relativerev = false;
$checkotherchunck = true; //always runs once
while (!$relativerev && $checkotherchunck) {
$tmp = array();
//parse in normal or reverse order
$count = count($lines);
if ($direction > 0) {
$start = 0;
$step = 1;
} else {
$start = $count - 1;
$step = -1;
}
for ($i = $start; $i >= 0 && $i < $count; $i = $i + $step) {
$tmp = parseChangelogLine($lines[$i]);
if ($tmp !== false) {
$this->cache[$this->id][$tmp['date']] = $tmp;
//look for revs older/earlier then reference $rev and select $direction-th one
if (($direction > 0 && $tmp['date'] > $rev) || ($direction < 0 && $tmp['date'] < $rev)) {
$revcounter++;
if ($revcounter == abs($direction)) {
$relativerev = $tmp['date'];
}
}
}
}
//true when $rev is found, but not the wanted follow-up.
$checkotherchunck = $fp
&& ($tmp['date'] == $rev || ($revcounter > 0 && !$relativerev))
&& !(($tail == $eof && $direction > 0) || ($head == 0 && $direction < 0));
if ($checkotherchunck) {
list($lines, $head, $tail) = $this->readAdjacentChunk($fp, $head, $tail, $direction);
if (empty($lines)) break;
}
}
if ($fp) {
fclose($fp);
}
return $relativerev;
}
/**
* Returns revisions around rev1 and rev2
* When available it returns $max entries for each revision
*
* @param int $rev1 oldest revision timestamp
* @param int $rev2 newest revision timestamp (0 looks up last revision)
* @param int $max maximum number of revisions returned
* @return array with two arrays with revisions surrounding rev1 respectively rev2
*/
public function getRevisionsAround($rev1, $rev2, $max = 50)
{
$max = floor(abs($max) / 2) * 2 + 1;
$rev1 = max($rev1, 0);
$rev2 = max($rev2, 0);
if ($rev2) {
if ($rev2 < $rev1) {
$rev = $rev2;
$rev2 = $rev1;
$rev1 = $rev;
}
} else {
//empty right side means a removed page. Look up last revision.
$revs = $this->getRevisions(-1, 1);
$rev2 = $revs[0];
}
//collect revisions around rev2
list($revs2, $allrevs, $fp, $lines, $head, $tail) = $this->retrieveRevisionsAround($rev2, $max);
if (empty($revs2)) return array(array(), array());
//collect revisions around rev1
$index = array_search($rev1, $allrevs);
if ($index === false) {
//no overlapping revisions
list($revs1, , , , ,) = $this->retrieveRevisionsAround($rev1, $max);
if (empty($revs1)) $revs1 = array();
} else {
//revisions overlaps, reuse revisions around rev2
$revs1 = $allrevs;
while ($head > 0) {
for ($i = count($lines) - 1; $i >= 0; $i--) {
$tmp = parseChangelogLine($lines[$i]);
if ($tmp !== false) {
$this->cache[$this->id][$tmp['date']] = $tmp;
$revs1[] = $tmp['date'];
$index++;
if ($index > floor($max / 2)) break 2;
}
}
list($lines, $head, $tail) = $this->readAdjacentChunk($fp, $head, $tail, -1);
}
sort($revs1);
//return wanted selection
$revs1 = array_slice($revs1, max($index - floor($max / 2), 0), $max);
}
return array(array_reverse($revs1), array_reverse($revs2));
}
/**
* Checks if the ID has old revisons
* @return boolean
*/
public function hasRevisions() {
$file = $this->getChangelogFilename();
return file_exists($file);
}
/**
* Returns lines from changelog.
* If file larger than $chuncksize, only chunck is read that could contain $rev.
*
* @param int $rev revision timestamp
* @return array|false
* if success returns array(fp, array(changeloglines), $head, $tail, $eof)
* where fp only defined for chuck reading, needs closing.
* otherwise false
*/
protected function readloglines($rev)
{
$file = $this->getChangelogFilename();
if (!file_exists($file)) {
return false;
}
$fp = null;
$head = 0;
$tail = 0;
$eof = 0;
if (filesize($file) < $this->chunk_size || $this->chunk_size == 0) {
// read whole file
$lines = file($file);
if ($lines === false) {
return false;
}
} else {
// read by chunk
$fp = fopen($file, 'rb'); // "file pointer"
if ($fp === false) {
return false;
}
$head = 0;
fseek($fp, 0, SEEK_END);
$eof = ftell($fp);
$tail = $eof;
// find chunk
while ($tail - $head > $this->chunk_size) {
$finger = $head + floor(($tail - $head) / 2.0);
$finger = $this->getNewlinepointer($fp, $finger);
$tmp = fgets($fp);
if ($finger == $head || $finger == $tail) {
break;
}
$tmp = parseChangelogLine($tmp);
$finger_rev = $tmp['date'];
if ($finger_rev > $rev) {
$tail = $finger;
} else {
$head = $finger;
}
}
if ($tail - $head < 1) {
// cound not find chunk, assume requested rev is missing
fclose($fp);
return false;
}
$lines = $this->readChunk($fp, $head, $tail);
}
return array(
$fp,
$lines,
$head,
$tail,
$eof,
);
}
/**
* Read chunk and return array with lines of given chunck.
* Has no check if $head and $tail are really at a new line
*
* @param resource $fp resource filepointer
* @param int $head start point chunck
* @param int $tail end point chunck
* @return array lines read from chunck
*/
protected function readChunk($fp, $head, $tail)
{
$chunk = '';
$chunk_size = max($tail - $head, 0); // found chunk size
$got = 0;
fseek($fp, $head);
while ($got < $chunk_size && !feof($fp)) {
$tmp = @fread($fp, max(min($this->chunk_size, $chunk_size - $got), 0));
if ($tmp === false) { //error state
break;
}
$got += strlen($tmp);
$chunk .= $tmp;
}
$lines = explode("\n", $chunk);
array_pop($lines); // remove trailing newline
return $lines;
}
/**
* Set pointer to first new line after $finger and return its position
*
* @param resource $fp filepointer
* @param int $finger a pointer
* @return int pointer
*/
protected function getNewlinepointer($fp, $finger)
{
fseek($fp, $finger);
$nl = $finger;
if ($finger > 0) {
fgets($fp); // slip the finger forward to a new line
$nl = ftell($fp);
}
return $nl;
}
/**
* Check whether given revision is the current page
*
* @param int $rev timestamp of current page
* @return bool true if $rev is current revision, otherwise false
*/
public function isCurrentRevision($rev)
{
return $rev == @filemtime($this->getFilename());
}
/**
* Return an existing revision for a specific date which is
* the current one or younger or equal then the date
*
* @param number $date_at timestamp
* @return string revision ('' for current)
*/
public function getLastRevisionAt($date_at)
{
//requested date_at(timestamp) younger or equal then modified_time($this->id) => load current
if (file_exists($this->getFilename()) && $date_at >= @filemtime($this->getFilename())) {
return '';
} else {
if ($rev = $this->getRelativeRevision($date_at + 1, -1)) { //+1 to get also the requested date revision
return $rev;
} else {
return false;
}
}
}
/**
* Returns the next lines of the changelog of the chunck before head or after tail
*
* @param resource $fp filepointer
* @param int $head position head of last chunk
* @param int $tail position tail of last chunk
* @param int $direction positive forward, negative backward
* @return array with entries:
* - $lines: changelog lines of readed chunk
* - $head: head of chunk
* - $tail: tail of chunk
*/
protected function readAdjacentChunk($fp, $head, $tail, $direction)
{
if (!$fp) return array(array(), $head, $tail);
if ($direction > 0) {
//read forward
$head = $tail;
$tail = $head + floor($this->chunk_size * (2 / 3));
$tail = $this->getNewlinepointer($fp, $tail);
} else {
//read backward
$tail = $head;
$head = max($tail - $this->chunk_size, 0);
while (true) {
$nl = $this->getNewlinepointer($fp, $head);
// was the chunk big enough? if not, take another bite
if ($nl > 0 && $tail <= $nl) {
$head = max($head - $this->chunk_size, 0);
} else {
$head = $nl;
break;
}
}
}
//load next chunck
$lines = $this->readChunk($fp, $head, $tail);
return array($lines, $head, $tail);
}
/**
* Collect the $max revisions near to the timestamp $rev
*
* @param int $rev revision timestamp
* @param int $max maximum number of revisions to be returned
* @return bool|array
* return array with entries:
* - $requestedrevs: array of with $max revision timestamps
* - $revs: all parsed revision timestamps
* - $fp: filepointer only defined for chuck reading, needs closing.
* - $lines: non-parsed changelog lines before the parsed revisions
* - $head: position of first readed changelogline
* - $lasttail: position of end of last readed changelogline
* otherwise false
*/
protected function retrieveRevisionsAround($rev, $max)
{
//get lines from changelog
list($fp, $lines, $starthead, $starttail, /* $eof */) = $this->readloglines($rev);
if (empty($lines)) return false;
//parse chunk containing $rev, and read forward more chunks until $max/2 is reached
$head = $starthead;
$tail = $starttail;
$revs = array();
$aftercount = $beforecount = 0;
while (count($lines) > 0) {
foreach ($lines as $line) {
$tmp = parseChangelogLine($line);
if ($tmp !== false) {
$this->cache[$this->id][$tmp['date']] = $tmp;
$revs[] = $tmp['date'];
if ($tmp['date'] >= $rev) {
//count revs after reference $rev
$aftercount++;
if ($aftercount == 1) $beforecount = count($revs);
}
//enough revs after reference $rev?
if ($aftercount > floor($max / 2)) break 2;
}
}
//retrieve next chunk
list($lines, $head, $tail) = $this->readAdjacentChunk($fp, $head, $tail, 1);
}
if ($aftercount == 0) return false;
$lasttail = $tail;
//read additional chuncks backward until $max/2 is reached and total number of revs is equal to $max
$lines = array();
$i = 0;
if ($aftercount > 0) {
$head = $starthead;
$tail = $starttail;
while ($head > 0) {
list($lines, $head, $tail) = $this->readAdjacentChunk($fp, $head, $tail, -1);
for ($i = count($lines) - 1; $i >= 0; $i--) {
$tmp = parseChangelogLine($lines[$i]);
if ($tmp !== false) {
$this->cache[$this->id][$tmp['date']] = $tmp;
$revs[] = $tmp['date'];
$beforecount++;
//enough revs before reference $rev?
if ($beforecount > max(floor($max / 2), $max - $aftercount)) break 2;
}
}
}
}
sort($revs);
//keep only non-parsed lines
$lines = array_slice($lines, 0, $i);
//trunk desired selection
$requestedrevs = array_slice($revs, -$max, $max);
return array($requestedrevs, $revs, $fp, $lines, $head, $lasttail);
}
}
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