2 rcs_id('$Id: backend.php,v 1.17 2004-11-27 14:39:05 rurban Exp $');
9 //:deleted (*) (Set if latest content is empty.)
17 %content (?should this be here?)
18 _supplanted : Time version ceased to be the current version
20 mtime (*) : Time of version edit.
23 author : nominal author
24 author_id : authenticated author
33 (types are scalars: strings, ints, bools)
37 * A WikiDB_backend handles the storage and retrieval of data for a WikiDB.
39 * A WikiDB_backend handles the storage and retrieval of data for a WikiDB.
40 * It does not have to be this way, of course, but the standard WikiDB uses
41 * a WikiDB_backend. (Other WikiDB's could be written which use some other
42 * method to access their underlying data store.)
44 * The interface outlined here seems to work well with both RDBM based
45 * and flat DBM/hash based methods of data storage.
47 * Though it contains some default implementation of certain methods,
48 * this is an abstract base class. It is expected that most effificient
49 * backends will override nearly all the methods in this class.
57 * Get page meta-data from database.
59 * @param $pagename string Page name.
61 * Returns a hash containing the page meta-data.
62 * Returns an empty array if there is no meta-data for the requested page.
63 * Keys which might be present in the hash are:
65 * <dt> locked <dd> If the page is locked.
66 * <dt> hits <dd> The page hit count.
67 * <dt> created <dd> Unix time of page creation. (FIXME: Deprecated: I
68 * don't think we need this...)
71 function get_pagedata($pagename) {
72 trigger_error("virtual", E_USER_ERROR);
76 * Update the page meta-data.
80 * Only meta-data whose keys are preset in $newdata is affected.
84 * $backend->update_pagedata($pagename, array('locked' => 1));
86 * will set the value of 'locked' to 1 for the specified page, but it
87 * will not affect the value of 'hits' (or whatever other meta-data
88 * may have been stored for the page.)
90 * To delete a particular piece of meta-data, set it's value to false.
92 * $backend->update_pagedata($pagename, array('locked' => false));
95 * @param $pagename string Page name.
96 * @param $newdata hash New meta-data.
98 function update_pagedata($pagename, $newdata) {
99 trigger_error("virtual", E_USER_ERROR);
104 * Get the current version number for a page.
106 * @param $pagename string Page name.
107 * @return int The latest version number for the page. Returns zero if
108 * no versions of a page exist.
110 function get_latest_version($pagename) {
111 trigger_error("virtual", E_USER_ERROR);
115 * Get preceding version number.
117 * @param $pagename string Page name.
118 * @param $version int Find version before this one.
119 * @return int The version number of the version in the database which
120 * immediately preceeds $version.
122 function get_previous_version($pagename, $version) {
123 trigger_error("virtual", E_USER_ERROR);
127 * Get revision meta-data and content.
129 * @param $pagename string Page name.
130 * @param $version integer Which version to get.
131 * @param $want_content boolean
132 * Indicates the caller really wants the page content. If this
133 * flag is not set, the backend is free to skip fetching of the
134 * page content (as that may be expensive). If the backend omits
135 * the content, the backend might still want to set the value of
136 * '%content' to the empty string if it knows there's no content.
138 * @return hash The version data, or false if specified version does not
141 * Some keys which might be present in the $versiondata hash are:
144 * <dd> This is a pseudo-meta-data element (since it's actually
145 * the page data, get it?) containing the page content.
146 * If the content was not fetched, this key may not be present.
148 * For description of other version meta-data see WikiDB_PageRevision::get().
149 * @see WikiDB_PageRevision::get
151 function get_versiondata($pagename, $version, $want_content = false) {
152 trigger_error("virtual", E_USER_ERROR);
156 * Delete page from the database.
158 * Delete page (and all it's revisions) from the database.
160 * This should remove all links (from the named page) from
163 * @param $pagename string Page name.
165 function delete_page($pagename) {
166 trigger_error("virtual", E_USER_ERROR);
170 * Delete an old revision of a page.
172 * Note that one is never allowed to delete the most recent version,
173 * but that this requirement is enforced by WikiDB not by the backend.
175 * In fact, to be safe, backends should probably allow the deletion of
176 * the most recent version.
178 * @param $pagename string Page name.
179 * @param $version integer Version to delete.
181 function delete_versiondata($pagename, $version) {
182 trigger_error("virtual", E_USER_ERROR);
186 * Create a new page revision.
188 * If the given ($pagename,$version) is already in the database,
189 * this method completely overwrites any stored data for that version.
191 * @param $pagename string Page name.
192 * @param $version int New revisions content.
193 * @param $data hash New revision metadata.
195 * @see get_versiondata
197 function set_versiondata($pagename, $version, $data) {
198 trigger_error("virtual", E_USER_ERROR);
202 * Update page version meta-data.
204 * If the given ($pagename,$version) is already in the database,
205 * this method only changes those meta-data values whose keys are
206 * explicity listed in $newdata.
208 * @param $pagename string Page name.
209 * @param $version int New revisions content.
210 * @param $newdata hash New revision metadata.
211 * @see set_versiondata, get_versiondata
213 function update_versiondata($pagename, $version, $newdata) {
214 $data = $this->get_versiondata($pagename, $version, true);
219 foreach ($newdata as $key => $val) {
225 $this->set_versiondata($pagename, $version, $data);
229 * Set links for page.
231 * @param $pagename string Page name.
233 * @param $links array List of page(names) which page links to.
235 function set_links($pagename, $links) {
236 trigger_error("virtual", E_USER_ERROR);
240 * Find pages which link to or are linked from a page.
242 * @param $pagename string Page name.
243 * @param $reversed boolean True to get backlinks.
245 * FIXME: array or iterator?
246 * @return object A WikiDB_backend_iterator.
248 function get_links($pagename, $reversed, $include_empty=false,
249 $sortby=false, $limit=false, $exclude=false) {
250 //FIXME: implement simple (but slow) link finder.
255 * Get all revisions of a page.
257 * @param $pagename string The page name.
258 * @return object A WikiDB_backend_iterator.
260 function get_all_revisions($pagename) {
261 include_once('lib/WikiDB/backend/dumb/AllRevisionsIter.php');
262 return new WikiDB_backend_dumb_AllRevisionsIter($this, $pagename);
266 * Get all pages in the database.
268 * Pages should be returned in alphabetical order if that is
273 * @param $include_defaulted boolean
274 * If set, even pages with no content will be returned
275 * --- but still only if they have at least one revision (not
276 * counting the default revision 0) entered in the database.
278 * Normally pages whose current revision has empty content
279 * are not returned as these pages are considered to be
282 * @return object A WikiDB_backend_iterator.
284 function get_all_pages($include_defaulted, $orderby=false, $limit=false, $exclude=false) {
285 trigger_error("virtual", E_USER_ERROR);
289 * Title or full text search.
291 * Pages should be returned in alphabetical order if that is
296 * @param $search object A TextSearchQuery object describing what pages
297 * are to be searched for.
299 * @param $fullsearch boolean If true, a full text search is performed,
300 * otherwise a title search is performed.
302 * @return object A WikiDB_backend_iterator.
304 * @see WikiDB::titleSearch
306 function text_search($search='', $fulltext=false) {
307 // This is method implements a simple linear search
308 // through all the pages in the database.
310 // It is expected that most backends will overload
311 // method with something more efficient.
312 include_once('lib/WikiDB/backend/dumb/TextSearchIter.php');
313 $pages = $this->get_all_pages(false);
314 return new WikiDB_backend_dumb_TextSearchIter($this, $pages, $search, $fulltext);
318 * Find pages with highest hit counts.
320 * Find the pages with the highest hit counts. The pages should
321 * be returned in reverse order by hit count.
324 * @param $limit integer No more than this many pages
325 * @return object A WikiDB_backend_iterator.
327 function most_popular($limit, $sortby='-hits') {
328 // This is method fetches all pages, then
329 // sorts them by hit count.
330 // (Not very efficient.)
332 // It is expected that most backends will overload
333 // method with something more efficient.
334 include_once('lib/WikiDB/backend/dumb/MostPopularIter.php');
335 $pages = $this->get_all_pages(false, $sortby, $limit);
337 return new WikiDB_backend_dumb_MostPopularIter($this, $pages, $limit);
341 * Find recent changes.
344 * @param $params hash See WikiDB::mostRecent for a description
345 * of parameters which can be included in this hash.
346 * @return object A WikiDB_backend_iterator.
347 * @see WikiDB::mostRecent
349 function most_recent($params) {
350 // This method is very inefficient and searches through
351 // all pages for the most recent changes.
353 // It is expected that most backends will overload
354 // method with something more efficient.
355 include_once('lib/WikiDB/backend/dumb/MostRecentIter.php');
356 $pages = $this->get_all_pages(true, '-mtime');
357 return new WikiDB_backend_dumb_MostRecentIter($this, $pages, $params);
360 function wanted_pages($exclude_from='', $exclude='', $sortby=false, $limit=false) {
361 include_once('lib/WikiDB/backend/dumb/WantedPagesIter.php');
362 $allpages = $this->get_all_pages(true,false,false,$exclude_from);
363 return new WikiDB_backend_dumb_WantedPagesIter($this, $allpages, $exclude, $sortby, $limit);
367 * Lock backend database.
369 * Calls may be nested.
371 * @param $write_lock boolean Unless this is set to false, a write lock
372 * is acquired, otherwise a read lock. If the backend doesn't support
373 * read locking, then it should make a write lock no matter which type
374 * of lock was requested.
376 * All backends <em>should</em> support write locking.
378 function lock($write_lock = true) {
382 * Unlock backend database.
384 * @param $force boolean Normally, the database is not unlocked until
385 * unlock() is called as many times as lock() has been. If $force is
386 * set to true, the the database is unconditionally unlocked.
388 function unlock($force = false) {
399 * Synchronize with filesystem.
401 * This should flush all unwritten data to the filesystem.
407 * Optimize the database.
409 function optimize() {
413 * Check database integrity.
415 * This should check the validity of the internal structure of the database.
416 * Errors should be reported via:
418 * trigger_error("Message goes here.", E_USER_WARNING);
421 * @return boolean True iff database is in a consistent state.
427 * Put the database into a consistent state.
429 * This should put the database into a consistent state.
430 * (I.e. rebuild indexes, etc...)
432 * @return boolean True iff successful.
437 function _parse_searchwords($search) {
438 $search = strtolower(trim($search));
440 return array(array(),array());
442 $words = preg_split('/\s+/', $search);
444 foreach ($words as $key => $word) {
445 if ($word[0] == '-' && $word != '-') {
446 $word = substr($word, 1);
447 $exclude[] = preg_quote($word);
451 return array($words, $exclude);
455 * Split the given limit parameter into offset,pagesize. (offset is optional. default: 0)
456 * Duplicate the PageList function here to avoid loading the whole PageList.php
458 * list($offset,$pagesize) = $this->limit($args['limit']);
460 function limit($limit) {
461 if (strstr($limit, ','))
462 return split(',', $limit);
464 return array(0, $limit);
468 * Handle sortby requests for the DB iterator and table header links.
469 * Prefix the column with + or - like "+pagename","-mtime", ...
470 * supported actions: 'flip_order' "mtime" => "+mtime" => "-mtime" ...
471 * 'db' "-pagename" => "pagename DESC"
472 * In PageList all columns are sortable. (patch by DanFr)
473 * Here with the backend only some, the rest is delayed to PageList.
474 * (some kind of DumbIter)
475 * Duplicate the PageList function here to avoid loading the whole
476 * PageList.php, and it forces the backend specific sortable_columns()
478 function sortby ($column, $action) {
479 if (empty($column)) return '';
480 //support multiple comma-delimited sortby args: "+hits,+pagename"
481 if (strstr($column,',')) {
483 foreach (explode(',',$column) as $col) {
484 $result[] = $this->sortby($col,$action);
486 return join(",",$result);
488 if (substr($column,0,1) == '+') {
489 $order = '+'; $column = substr($column,1);
490 } elseif (substr($column,0,1) == '-') {
491 $order = '-'; $column = substr($column,1);
493 // default order: +pagename, -mtime, -hits
495 if (in_array($column,array('mtime','hits')))
499 if ($action == 'flip_order') {
500 return ($order == '+' ? '-' : '+') . $column;
501 } elseif ($action == 'init') {
502 $this->_sortby[$column] = $order;
503 return $order . $column;
504 } elseif ($action == 'check') {
505 return (!empty($this->_sortby[$column]) or
506 ($GLOBALS['request']->getArg('sortby') and
507 strstr($GLOBALS['request']->getArg('sortby'),$column)));
508 } elseif ($action == 'db') {
509 // native sort possible?
510 $sortable_columns = $this->sortable_columns();
511 if (in_array($column, $sortable_columns))
512 // asc or desc: +pagename, -pagename
513 return $column . ($order == '+' ? ' ASC' : ' DESC');
520 function sortable_columns() {
521 return array('pagename'/*,'mtime','author_id','author'*/);
524 // adds surrounding quotes
525 function quote ($s) { return "'".$s."'"; }
526 // no surrounding quotes because we know it's a string
527 function qstr ($s) { return $s; }
532 * Iterator returned by backend methods which (possibly) return
535 * FIXME: This might be two seperate classes: page_iter and version_iter.
536 * For the versions we have WikiDB_backend_dumb_AllRevisionsIter.
538 class WikiDB_backend_iterator
541 * Get the next record in the iterator set.
543 * This returns a hash. The hash may contain the following keys:
545 * <dt> pagename <dt> (string) the page name
546 * <dt> version <dt> (int) the version number
547 * <dt> pagedata <dt> (hash) page meta-data (as returned from backend::get_pagedata().)
548 * <dt> versiondata <dt> (hash) page meta-data (as returned from backend::get_versiondata().)
550 * If this is a page iterator, it must contain the 'pagename' entry --- the others
553 * If this is a version iterator, the 'pagename', 'version', <strong>and</strong> 'versiondata'
554 * entries are mandatory. ('pagedata' is optional.)
557 trigger_error("virtual", E_USER_ERROR);
561 return count($this->_pages);
565 * Release resources held by this iterator.
572 * search baseclass, pcre-specific. only overriden by sql backends.
574 class WikiDB_backend_search
576 function WikiDB_backend_search(&$dbh, $search) {
578 $this->_case_exact = $search->_case_exact;
580 function _quote($word) {
581 return preg_quote($word, "/");
583 //TODO: use word anchors
584 function EXACT($word) { return "^".$this->_quote($word)."$"; }
585 function STARTS_WITH($word) { return "^".$this->_quote($word); }
586 function ENDS_WITH($word) { return $this->_quote($word)."$"; }
587 function WORD($word) { return $this->_quote($word); }
588 function REGEX($word) { return $word; }
590 function _pagename_match_clause($node) {
592 $word = $this->$method($node->word);
593 return "preg_match(\"/\".$word.\"/\"".($this->_case_exact ? "i":"").")";
603 // c-hanging-comment-ender-p: nil
604 // indent-tabs-mode: nil