xref: /dokuwiki/inc/ChangeLog/ChangeLogTrait.php (revision d41f5a8f13cbe65aecfb29abc34975970b616198) 
1<?php
2
3namespace dokuwiki\ChangeLog;
4
5use dokuwiki\Utf8\PhpString;
6
7/**
8 * Provides methods for handling of changelog
9 */
10trait ChangeLogTrait
11{
12    /**
13     * Adds an entry to the changelog file
14     *
15     * @return array added log line as revision info
16     */
17    abstract public function addLogEntry(array $info, $timestamp = null);
18
19    /**
20     * Parses a changelog line into its components
21     *
22     * @param string $line changelog line
23     * @return array|bool parsed line or false
24     * @author Ben Coburn <btcoburn@silicodon.net>
25     *
26     */
27    public static function parseLogLine($line)
28    {
29        $info = sexplode("\t", rtrim($line, "\n"), 8);
30        if ($info[3]) { // we need at least the page id to consider it a valid line
31            return [
32                'date' => (int)$info[0], // unix timestamp
33                'ip' => $info[1], // IP address (127.0.0.1)
34                'type' => $info[2], // log line type
35                'id' => $info[3], // page id
36                'user' => $info[4], // user name
37                'sum' => $info[5], // edit summary (or action reason)
38                'extra' => $info[6], // extra data (varies by line type)
39                'sizechange' => ($info[7] != '') ? (int)$info[7] : null, // size difference in bytes
40            ];
41        } else {
42            return false;
43        }
44    }
45
46    /**
47     * Build a changelog line from its components
48     *
49     * @param array $info Revision info structure
50     * @param int $timestamp log line date (optional)
51     * @return string changelog line
52     */
53    public static function buildLogLine(array &$info, $timestamp = null)
54    {
55        $strip = ["\t", "\n"];
56        $entry = [
57            'date' => $timestamp ?? $info['date'],
58            'ip' => $info['ip'],
59            'type' => str_replace($strip, '', $info['type']),
60            'id' => $info['id'],
61            'user' => $info['user'],
62            'sum' => PhpString::substr(str_replace($strip, '', $info['sum'] ?? ''), 0, 255),
63            'extra' => str_replace($strip, '', $info['extra']),
64            'sizechange' => $info['sizechange']
65        ];
66        $info = $entry;
67        return implode("\t", $entry) . "\n";
68    }
69
70    /**
71     * Returns path to changelog
72     *
73     * @return string path to file
74     */
75    abstract protected function getChangelogFilename();
76
77    /**
78     * Checks if the ID has old revisions
79     * @return boolean
80     */
81    public function hasRevisions()
82    {
83        $logfile = $this->getChangelogFilename();
84        return file_exists($logfile);
85    }
86
87
88    /** @var int */
89    protected $chunk_size;
90
91    /**
92     * Set chunk size for file reading
93     * Chunk size zero let read whole file at once
94     *
95     * @param int $chunk_size maximum block size read from file
96     */
97    public function setChunkSize($chunk_size)
98    {
99        if (!is_numeric($chunk_size)) $chunk_size = 0;
100
101        $this->chunk_size = max($chunk_size, 0);
102    }
103
104    /**
105     * Returns lines from changelog.
106     * If file larger than $chunk_size, only chunk is read that could contain $rev.
107     *
108     * When reference timestamp $rev is outside time range of changelog, readloglines() will return
109     * lines in first or last chunk, but they obviously does not contain $rev.
110     *
111     * @param int $rev revision timestamp
112     * @return array|false
113     *     if success returns array(fp, array(changeloglines), $head, $tail, $eof)
114     *     where fp only defined for chuck reading, needs closing.
115     *     otherwise false
116     */
117    protected function readloglines($rev)
118    {
119        $file = $this->getChangelogFilename();
120
121        if (!file_exists($file)) {
122            return false;
123        }
124
125        $fp = null;
126        $head = 0;
127        $tail = 0;
128        $eof = 0;
129
130        if (filesize($file) < $this->chunk_size || $this->chunk_size == 0) {
131            // read whole file
132            $lines = file($file);
133            if ($lines === false) {
134                return false;
135            }
136        } else {
137            // read by chunk
138            $fp = fopen($file, 'rb'); // "file pointer"
139            if ($fp === false) {
140                return false;
141            }
142            fseek($fp, 0, SEEK_END);
143            $eof = ftell($fp);
144            $tail = $eof;
145
146            // find chunk
147            while ($tail - $head > $this->chunk_size) {
148                $finger = $head + (int)(($tail - $head) / 2);
149                $finger = $this->getNewlinepointer($fp, $finger);
150                $tmp = fgets($fp);
151                if ($finger == $head || $finger == $tail) {
152                    break;
153                }
154                $info = $this->parseLogLine($tmp);
155                if (!is_array($info)) {
156                    // skip unparsable lines, but still advance the search boundary
157                    $head = $finger;
158                    continue;
159                }
160                $finger_rev = $info['date'];
161
162                if ($finger_rev > $rev) {
163                    $tail = $finger;
164                } else {
165                    $head = $finger;
166                }
167            }
168
169            if ($tail - $head < 1) {
170                // could not find chunk, assume requested rev is missing
171                fclose($fp);
172                return false;
173            }
174
175            $lines = $this->readChunk($fp, $head, $tail);
176        }
177        return [$fp, $lines, $head, $tail, $eof];
178    }
179
180    /**
181     * Read chunk and return array with lines of given chunk.
182     * Has no check if $head and $tail are really at a new line
183     *
184     * @param resource $fp resource file pointer
185     * @param int $head start point chunk
186     * @param int $tail end point chunk
187     * @return array lines read from chunk
188     */
189    protected function readChunk($fp, $head, $tail)
190    {
191        $chunk = '';
192        $chunk_size = max($tail - $head, 0); // found chunk size
193        $got = 0;
194        fseek($fp, $head);
195        while ($got < $chunk_size && !feof($fp)) {
196            $tmp = @fread($fp, max(min($this->chunk_size, $chunk_size - $got), 0));
197            if ($tmp === false) { //error state
198                break;
199            }
200            $got += strlen($tmp);
201            $chunk .= $tmp;
202        }
203        $lines = explode("\n", $chunk);
204        array_pop($lines); // remove trailing newline
205        return $lines;
206    }
207
208    /**
209     * Set pointer to first new line after $finger and return its position
210     *
211     * @param resource $fp file pointer
212     * @param int $finger a pointer
213     * @return int pointer
214     */
215    protected function getNewlinepointer($fp, $finger)
216    {
217        fseek($fp, $finger);
218        $nl = $finger;
219        if ($finger > 0) {
220            fgets($fp); // slip the finger forward to a new line
221            $nl = ftell($fp);
222        }
223        return $nl;
224    }
225
226    /**
227     * Returns the next lines of the changelog  of the chunk before head or after tail
228     *
229     * @param resource $fp file pointer
230     * @param int $head position head of last chunk
231     * @param int $tail position tail of last chunk
232     * @param int $direction positive forward, negative backward
233     * @return array with entries:
234     *    - $lines: changelog lines of read chunk
235     *    - $head: head of chunk
236     *    - $tail: tail of chunk
237     */
238    protected function readAdjacentChunk($fp, $head, $tail, $direction)
239    {
240        if (!$fp) return [[], $head, $tail];
241
242        if ($direction > 0) {
243            //read forward
244            $head = $tail;
245            $tail = $head + (int)($this->chunk_size * (2 / 3));
246            $tail = $this->getNewlinepointer($fp, $tail);
247        } else {
248            //read backward
249            $tail = $head;
250            $head = max($tail - $this->chunk_size, 0);
251            while (true) {
252                $nl = $this->getNewlinepointer($fp, $head);
253                // was the chunk big enough? if not, take another bite
254                if ($nl > 0 && $tail <= $nl) {
255                    $head = max($head - $this->chunk_size, 0);
256                } else {
257                    $head = $nl;
258                    break;
259                }
260            }
261        }
262
263        //load next chunk
264        $lines = $this->readChunk($fp, $head, $tail);
265        return [$lines, $head, $tail];
266    }
267}
268