/**
* Helper method to write information about some redirect. Various updates
* can be necessary if redirects are resolved as identities in SMW. The
* title and namespace of the affected page and of its updated redirect
* target are given. The target can be empty ('') to delete any redirect.
* Returns the canonical ID that is now to be used for the subject.
*
* This method does not change the ids of the affected pages, and thus it
* is not concerned with updates of the data that is currently stored for
* the subject. Normally, a subject that is a redirect will not have other
* data, but this method does not depend on this.
*
* @note Please make sure you fully understand this code before making any
* changes here. Keeping the redirect structure consistent is important,
* and errors in this code can go unnoticed for quite some time.
*
* @note This method merely handles the addition or deletion of a redirect
* statement in the wiki. It does not assume that any page contents has
* been changed (e.g. moved). See changeTitle() for additional handling in
* this case.
*
* @todo Clean up this code.
*
* @since 1.8
* @param string $subject_t
* @param integer $subject_ns
* @param string $curtarget_t
* @param integer $curtarget_ns
* @return integer the new canonical ID of the subject
*/
protected function updateRedirects($subject_t, $subject_ns, $curtarget_t = '', $curtarget_ns = -1)
{
global $smwgQEqualitySupport, $smwgEnableUpdateJobs;
$count = 0;
//track count changes for redi property
$db = $this->store->getConnection();
// *** First get id of subject, old redirect target, and current (new) redirect target ***//
$sid_sort = '';
// find real id of subject, if any
$sid = $this->store->getObjectIds()->getSMWPageIDandSort($subject_t, $subject_ns, '', '', $sid_sort, false);
/// NOTE: $sid can be 0 here; this is useful to know since it means that fewer table updates are needed
$new_tid = $curtarget_t ? $this->store->getObjectIds()->makeSMWPageID($curtarget_t, $curtarget_ns, '', '', false) : 0;
// real id of new target, if given
$old_tid = $this->store->getObjectIds()->findRedirectIdFor($subject_t, $subject_ns);
/// NOTE: $old_tid and $new_tid both (intentionally) ignore further redirects: no redirect chains
if ($old_tid == $new_tid) {
// no change, all happy
return $new_tid == 0 ? $sid : $new_tid;
}
// note that this means $old_tid != $new_tid in all cases below
// *** Make relevant changes in property tables (don't write the new redirect yet) ***//
$jobs = array();
if ($old_tid == 0 && $sid != 0 && $smwgQEqualitySupport != SMW_EQ_NONE) {
// new redirect
// $smwgQEqualitySupport requires us to change all tables' page references from $sid to $new_tid.
// Since references must not be 0, we don't have to do this is $sid == 0.
$this->store->changeSMWPageID($sid, $new_tid, $subject_ns, $curtarget_ns, false, true);
$jobs = $this->makeUpdateJobsForNewRedirect($subject_t, $subject_ns, $curtarget_t, $curtarget_ns);
} elseif ($old_tid != 0) {
// existing redirect is changed or deleted
$this->store->getObjectIds()->deleteRedirectEntry($subject_t, $subject_ns);
$count--;
if ($this->store->getUpdateJobsEnabledState() && $smwgQEqualitySupport != SMW_EQ_NONE) {
// entries that refer to old target may in fact refer to subject,
// but we don't know which: schedule affected pages for update
$propertyTables = $this->store->getPropertyTables();
foreach ($propertyTables as $proptable) {
if ($proptable->getName() == 'smw_fpt_redi') {
continue;
// can safely be skipped
}
if ($proptable->usesIdSubject()) {
$from = $db->tableName($proptable->getName()) . ' INNER JOIN ' . $db->tableName(SMWSql3SmwIds::tableName) . ' ON s_id=smw_id';
$select = 'DISTINCT smw_title AS t,smw_namespace AS ns';
} else {
$from = $db->tableName($proptable->getName());
$select = 'DISTINCT s_title AS t,s_namespace AS ns';
}
if ($subject_ns === SMW_NS_PROPERTY && !$proptable->isFixedPropertyTable()) {
$res = $db->select($from, $select, array('p_id' => $old_tid), __METHOD__);
foreach ($res as $row) {
$title = Title::makeTitleSafe($row->ns, $row->t);
if (!is_null($title)) {
$jobs[] = new UpdateJob($title);
}
}
$db->freeResult($res);
}
foreach ($proptable->getFields($this->store) as $fieldname => $type) {
if ($type == 'p') {
$res = $db->select($from, $select, array($fieldname => $old_tid), __METHOD__);
foreach ($res as $row) {
$title = Title::makeTitleSafe($row->ns, $row->t);
if (!is_null($title)) {
$jobs[] = new UpdateJob($title);
}
}
$db->freeResult($res);
}
}
}
/// NOTE: we do not update the concept cache here; this remains an offline task
}
}
if ($this->store->getUpdateJobsEnabledState()) {
JobBase::batchInsert($jobs);
}
// *** Finally, write the new redirect data ***//
if ($new_tid != 0) {
// record a new redirect
// Redirecting done right:
// (1) make a new ID with iw SMW_SQL3_SMWREDIIW or
// change iw field of current ID in this way,
// (2) write smw_fpt_redi table,
// (3) update canonical cache.
// This order must be obeyed unless you really understand what you are doing!
if ($old_tid == 0 && $smwgQEqualitySupport != SMW_EQ_NONE) {
// mark subject as redirect (if it was no redirect before)
if ($sid == 0) {
// every redirect page must have an ID
$sid = $this->store->getObjectIds()->makeSMWPageID($subject_t, $subject_ns, SMW_SQL3_SMWREDIIW, '', false);
} else {
$db->update(SMWSql3SmwIds::tableName, array('smw_iw' => SMW_SQL3_SMWREDIIW), array('smw_id' => $sid), __METHOD__);
$this->store->getObjectIds()->setCache($subject_t, $subject_ns, '', '', 0, '');
$this->store->getObjectIds()->setCache($subject_t, $subject_ns, SMW_SQL3_SMWREDIIW, '', $sid, $sid_sort);
}
}
$this->store->getObjectIds()->addRedirectForId($new_tid, $subject_t, $subject_ns);
$count++;
} else {
// delete old redirect
// This case implies $old_tid != 0 (or we would have new_tid == old_tid above).
// Therefore $subject had a redirect, and it must also have an ID.
// This shows that $sid != 0 here.
if ($smwgQEqualitySupport != SMW_EQ_NONE) {
// mark subject as non-redirect
$db->update(SMWSql3SmwIds::tableName, array('smw_iw' => ''), array('smw_id' => $sid), __METHOD__);
$this->store->getObjectIds()->setCache($subject_t, $subject_ns, SMW_SQL3_SMWREDIIW, '', 0, '');
$this->store->getObjectIds()->setCache($subject_t, $subject_ns, '', '', $sid, $sid_sort);
}
}
// *** Flush some caches to be safe, though they are not essential in runs with redirect updates ***//
unset($this->store->m_semdata[$sid]);
unset($this->store->m_semdata[$new_tid]);
unset($this->store->m_semdata[$old_tid]);
unset($this->store->m_sdstate[$sid]);
unset($this->store->m_sdstate[$new_tid]);
unset($this->store->m_sdstate[$old_tid]);
// *** Update reference count for _REDI property ***//
$statsTable = new PropertyStatisticsTable($db, SMWSQLStore3::PROPERTY_STATISTICS_TABLE);
$statsTable->addToUsageCount($this->store->getObjectIds()->getSMWPropertyID(new SMWDIProperty('_REDI')), $count);
return $new_tid == 0 ? $sid : $new_tid;
}
