split changelog classes into their own namespace

The remaining functions in inc/changelog.php should be moved into a
utility class.

20 files changed, 794 insertions, 693 deletions

diff --git a/_test/tests/inc/changelog_getRevisionsAround.test.php b/_test/tests/inc/changelog_getRevisionsAround.test.php
index 2a5cb849e..ad6d3afcf 100644
--- a/_test/tests/inc/changelog_getRevisionsAround.test.php
+++ b/_test/tests/inc/changelog_getRevisionsAround.test.php
@@ -1,4 +1,7 @@
 <?php
+
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * Tests for requesting revisions of a page with getRevisions()
  *
@@ -185,4 +188,4 @@ class changelog_getrevisionsaround_test extends DokuWikiTest {
         $this->assertEquals($revsexpected, $revs);
     }
 
-}
\ No newline at end of file
+}
diff --git a/_test/tests/inc/changelog_getlastrevisionat.test.php b/_test/tests/inc/changelog_getlastrevisionat.test.php
index 4ab7900b6..cec54f6db 100644
--- a/_test/tests/inc/changelog_getlastrevisionat.test.php
+++ b/_test/tests/inc/changelog_getlastrevisionat.test.php
@@ -1,5 +1,8 @@
 <?php
 
+use dokuwiki\ChangeLog\MediaChangeLog;
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * Tests for requesting revisioninfo of a revision of a page with getRevisionInfo()
  *
@@ -10,7 +13,7 @@
 class changelog_getlastrevisionat_test extends DokuWikiTest {
 
     private $pageid = 'mailinglist';
-    
+
     function setup() {
         parent::setup();
         global $cache_revinfo;
@@ -22,7 +25,7 @@ class changelog_getlastrevisionat_test extends DokuWikiTest {
             unset($cache['mailinglist']);
         }
     }
-    
+
 
     /**
      * no nonexist.changes meta file available
@@ -53,7 +56,7 @@ class changelog_getlastrevisionat_test extends DokuWikiTest {
         $this->assertEquals($revsexpected, $revs);
 
     }
-    
+
     /**
      * test a future revision
      *
@@ -64,7 +67,7 @@ class changelog_getlastrevisionat_test extends DokuWikiTest {
 
         //set a known timestamp
         touch(wikiFN($this->pageid), $rev);
-        
+
         $rev +=1;
 
         $pagelog = new PageChangeLog($this->pageid, $chunk_size = 8192);
@@ -89,7 +92,7 @@ class changelog_getlastrevisionat_test extends DokuWikiTest {
 
     /**
      * Request not existing revision
-     * 
+     *
      */
     function test_olderrev() {
         $rev = 1;
@@ -124,7 +127,7 @@ class changelog_getlastrevisionat_test extends DokuWikiTest {
         $current = $pagelog->getLastRevisionAt($rev);
         $this->assertEquals($currentexpected, $current);
     }
-    
+
     /**
      * test get correct revision on deleted media
      *
@@ -154,13 +157,13 @@ class changelog_getlastrevisionat_test extends DokuWikiTest {
 
         $ret = media_delete($image, 0);
 
-        $medialog = new MediaChangelog($image);
+        $medialog = new MediaChangeLog($image);
         $current = $medialog->getLastRevisionAt($rev);
         // as we wait for a tick, we should get something greater than the timestamp
         $this->assertGreaterThan($revexpected, $current);
         // however, it should be less than the current time or equal to it
         $this->assertLessThanOrEqual(time(), $current);
-        
+
         //restore settings
         $_SERVER['REMOTE_USER'] = $oldRemoteUser;
         $conf['superuser'] = $oldSuperUser;
diff --git a/_test/tests/inc/changelog_getrelativerevision.test.php b/_test/tests/inc/changelog_getrelativerevision.test.php
index f9962066a..49d7a0915 100644
--- a/_test/tests/inc/changelog_getrelativerevision.test.php
+++ b/_test/tests/inc/changelog_getrelativerevision.test.php
@@ -1,5 +1,7 @@
 <?php
 
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * Tests for requesting revisioninfo of a revision of a page with getRevisionInfo()
  *
@@ -415,4 +417,4 @@ class changelog_getrelativerevision_test extends DokuWikiTest {
         $current = $pagelog->isCurrentRevision($rev);
         $this->assertEquals($currentexpected, $current);
     }
-}
\ No newline at end of file
+}
diff --git a/_test/tests/inc/changelog_getrevisioninfo.test.php b/_test/tests/inc/changelog_getrevisioninfo.test.php
index 79b31d68e..2d7ad131a 100644
--- a/_test/tests/inc/changelog_getrevisioninfo.test.php
+++ b/_test/tests/inc/changelog_getrevisioninfo.test.php
@@ -1,5 +1,7 @@
 <?php
 
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * Tests for requesting revisioninfo of a revision of a page with getRevisionInfo()
  *
@@ -137,4 +139,4 @@ class changelog_getrevisionsinfo_test extends DokuWikiTest {
         $info = $pagelog->getRevisionInfo($rev);
         $this->assertEquals($infoexpected, $info);
     }
-}
\ No newline at end of file
+}
diff --git a/_test/tests/inc/changelog_getrevisions.test.php b/_test/tests/inc/changelog_getrevisions.test.php
index b247ce3d6..e29b80997 100644
--- a/_test/tests/inc/changelog_getrevisions.test.php
+++ b/_test/tests/inc/changelog_getrevisions.test.php
@@ -1,4 +1,7 @@
 <?php
+
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * Tests for requesting revisions of a page with getRevisions()
  *
@@ -227,4 +230,4 @@ class changelog_getrevisions_test extends DokuWikiTest {
         $this->assertEquals($revsexpected, $revs);
     }
 
-}
\ No newline at end of file
+}
diff --git a/_test/tests/inc/common_saveWikiText.test.php b/_test/tests/inc/common_saveWikiText.test.php
index fe83caabd..d363fbf0e 100644
--- a/_test/tests/inc/common_saveWikiText.test.php
+++ b/_test/tests/inc/common_saveWikiText.test.php
@@ -1,5 +1,7 @@
 <?php
 
+use dokuwiki\ChangeLog\PageChangeLog;
+
 class common_saveWikiText_test extends DokuWikiTest {
     /** Delay writes of old revisions by a second. */
     public function handle_write(Doku_Event $event, $param) {
diff --git a/feed.php b/feed.php
index 65d751b3e..cd1e11792 100644
--- a/feed.php
+++ b/feed.php
@@ -9,6 +9,9 @@
  * @global Input $INPUT
  */
 
+use dokuwiki\ChangeLog\MediaChangeLog;
+use dokuwiki\ChangeLog\PageChangeLog;
+
 if(!defined('DOKU_INC')) define('DOKU_INC', dirname(__FILE__).'/');
 require_once(DOKU_INC.'inc/init.php');
 
diff --git a/inc/ChangeLog/ChangeLog.php b/inc/ChangeLog/ChangeLog.php
new file mode 100644
index 000000000..a39d0b959
--- /dev/null
+++ b/inc/ChangeLog/ChangeLog.php
@@ -0,0 +1,657 @@
+<?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;
+                } // already read all the lines
+                else {
+                    $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));
+    }
+
+    /**
+     * 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, $lasttail);
+    }
+}
diff --git a/inc/ChangeLog/MediaChangeLog.php b/inc/ChangeLog/MediaChangeLog.php
new file mode 100644
index 000000000..0d7d8d390
--- /dev/null
+++ b/inc/ChangeLog/MediaChangeLog.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace dokuwiki\ChangeLog;
+
+/**
+ * handles changelog of a media file
+ */
+class MediaChangeLog extends ChangeLog
+{
+
+    /**
+     * Returns path to changelog
+     *
+     * @return string path to file
+     */
+    protected function getChangelogFilename()
+    {
+        return mediaMetaFN($this->id, '.changes');
+    }
+
+    /**
+     * Returns path to current page/media
+     *
+     * @return string path to file
+     */
+    protected function getFilename()
+    {
+        return mediaFN($this->id);
+    }
+}
diff --git a/inc/ChangeLog/PageChangeLog.php b/inc/ChangeLog/PageChangeLog.php
new file mode 100644
index 000000000..f1b91dee6
--- /dev/null
+++ b/inc/ChangeLog/PageChangeLog.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace dokuwiki\ChangeLog;
+
+/**
+ * handles changelog of a wiki page
+ */
+class PageChangeLog extends ChangeLog
+{
+
+    /**
+     * Returns path to changelog
+     *
+     * @return string path to file
+     */
+    protected function getChangelogFilename()
+    {
+        return metaFN($this->id, '.changes');
+    }
+
+    /**
+     * Returns path to current page/media
+     *
+     * @return string path to file
+     */
+    protected function getFilename()
+    {
+        return wikiFN($this->id);
+    }
+}
diff --git a/inc/Remote/ApiCore.php b/inc/Remote/ApiCore.php
index 6a7c0c81d..cea0a9dc7 100644
--- a/inc/Remote/ApiCore.php
+++ b/inc/Remote/ApiCore.php
@@ -3,9 +3,9 @@
 namespace dokuwiki\Remote;
 
 use Doku_Renderer_xhtml;
+use dokuwiki\ChangeLog\MediaChangeLog;
+use dokuwiki\ChangeLog\PageChangeLog;
 use DokuWiki_Auth_Plugin;
-use MediaChangeLog;
-use PageChangeLog;
 
 define('DOKU_API_VERSION', 10);
 
diff --git a/inc/changelog.php b/inc/changelog.php
index 1981a7d8f..4cf2bc299 100644
--- a/inc/changelog.php
+++ b/inc/changelog.php
@@ -393,682 +393,3 @@ function _handleRecent($line,$ns,$flags,&$seen){
 
     return $recent;
 }
-
-/**
- * Class 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;
-                } // already read all the lines
-                else {
-                    $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) - $first, 0)); }
-        else if($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));
-    }
-
-    /**
-     * 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, $lasttail);
-    }
-}
-
-/**
- * Class PageChangelog handles changelog of a wiki page
- */
-class PageChangelog extends ChangeLog {
-
-    /**
-     * Returns path to changelog
-     *
-     * @return string path to file
-     */
-    protected function getChangelogFilename() {
-        return metaFN($this->id, '.changes');
-    }
-
-    /**
-     * Returns path to current page/media
-     *
-     * @return string path to file
-     */
-    protected function getFilename() {
-        return wikiFN($this->id);
-    }
-}
-
-/**
- * Class MediaChangelog handles changelog of a media file
- */
-class MediaChangelog extends ChangeLog {
-
-    /**
-     * Returns path to changelog
-     *
-     * @return string path to file
-     */
-    protected function getChangelogFilename() {
-        return mediaMetaFN($this->id, '.changes');
-    }
-
-    /**
-     * Returns path to current page/media
-     *
-     * @return string path to file
-     */
-    protected function getFilename() {
-        return mediaFN($this->id);
-    }
-}
diff --git a/inc/common.php b/inc/common.php
index cfaac7f92..71c24e680 100644
--- a/inc/common.php
+++ b/inc/common.php
@@ -6,6 +6,8 @@
  * @author     Andreas Gohr <andi@splitbrain.org>
  */
 
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * These constants are used with the recents function
  */
diff --git a/inc/deprecated.php b/inc/deprecated.php
index 54b63997b..15dd51730 100644
--- a/inc/deprecated.php
+++ b/inc/deprecated.php
@@ -77,3 +77,29 @@ class setting_string extends \dokuwiki\plugin\config\core\Setting\SettingString
         parent::__construct($key, $params);
     }
 }
+
+/**
+ * @inheritdoc
+ * @deprecated 2018-06-15
+ */
+class PageChangelog extends \dokuwiki\ChangeLog\PageChangeLog {
+    /** @inheritdoc */
+    public function __construct($id, $chunk_size = 8192)
+    {
+        dbg_deprecated(\dokuwiki\ChangeLog\PageChangeLog::class);
+        parent::__construct($id, $chunk_size);
+    }
+}
+
+/**
+ * @inheritdoc
+ * @deprecated 2018-06-15
+ */
+class MediaChangelog extends \dokuwiki\ChangeLog\MediaChangeLog {
+    /** @inheritdoc */
+    public function __construct($id, $chunk_size = 8192)
+    {
+        dbg_deprecated(\dokuwiki\ChangeLog\MediaChangeLog::class);
+        parent::__construct($id, $chunk_size);
+    }
+}
diff --git a/inc/html.php b/inc/html.php
index 68f8f9e9b..5fec9686d 100644
--- a/inc/html.php
+++ b/inc/html.php
@@ -6,6 +6,9 @@
  * @author     Andreas Gohr <andi@splitbrain.org>
  */
 
+use dokuwiki\ChangeLog\MediaChangeLog;
+use dokuwiki\ChangeLog\PageChangeLog;
+
 if (!defined('SEC_EDIT_PATTERN')) {
     define('SEC_EDIT_PATTERN', '#<!-- EDIT({.*?}) -->#');
 }
diff --git a/inc/media.php b/inc/media.php
index 5feefcd53..2a50c9b64 100644
--- a/inc/media.php
+++ b/inc/media.php
@@ -6,6 +6,8 @@
  * @author     Andreas Gohr <andi@splitbrain.org>
  */
 
+use dokuwiki\ChangeLog\MediaChangeLog;
+
 /**
  * Lists pages which currently use a media file selected for deletion
  *
diff --git a/inc/pageutils.php b/inc/pageutils.php
index 55eda5514..a37d5739b 100644
--- a/inc/pageutils.php
+++ b/inc/pageutils.php
@@ -7,6 +7,9 @@
  * @todo       Combine similar functions like {wiki,media,meta}FN()
  */
 
+use dokuwiki\ChangeLog\MediaChangeLog;
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * Fetch the an ID from request
  *
diff --git a/inc/parser/xhtml.php b/inc/parser/xhtml.php
index 1b4387d2b..98a7d7f23 100644
--- a/inc/parser/xhtml.php
+++ b/inc/parser/xhtml.php
@@ -1,4 +1,7 @@
 <?php
+
+use dokuwiki\ChangeLog\MediaChangeLog;
+
 /**
  * Renderer for XHTML output
  *
diff --git a/inc/subscription.php b/inc/subscription.php
index 3dbebcbf5..80b301ed5 100644
--- a/inc/subscription.php
+++ b/inc/subscription.php
@@ -1,4 +1,7 @@
 <?php
+
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * Class for handling (email) subscriptions
  *
diff --git a/lib/plugins/revert/admin.php b/lib/plugins/revert/admin.php
index e6790a962..2d11dc05a 100644
--- a/lib/plugins/revert/admin.php
+++ b/lib/plugins/revert/admin.php
@@ -1,4 +1,7 @@
 <?php
+
+use dokuwiki\ChangeLog\PageChangeLog;
+
 /**
  * All DokuWiki plugins to extend the admin function
  * need to inherit from this class