Checking case sensitivity for mysql tag tables (bug #1231920)

Compressing array of tags to unique case insensitive values if needed

Eg
array('Test','cat','test','TEST','Cat');

will become
array('Test','cat');

for mysql sites that have case insensitive tables

Change-Id: Idf0b8a4440ef0f9273d5be685cf7ad22fecc746a
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>

htdocs/admin/users/edit.php

@@ -487,6 +487,7 @@ function edituser_site_submit(Pieform $form, $values) {
 
     delete_records('usr_tag', 'usr', $user->id);
     if (is_array($values['tags'])) {
+        $values['tags'] = check_case_sensitive($values['tags'], 'usr_tag');
         foreach(array_unique($values['tags']) as $tag) {
             if (empty($tag)) {
                 continue;

htdocs/artefact/lib.php

@@ -453,6 +453,7 @@ abstract class ArtefactType {
 
         delete_records('artefact_tag', 'artefact', $this->id);
         if (is_array($this->tags)) {
+            $this->tags = check_case_sensitive($this->tags, 'artefact_tag');
             foreach (array_unique($this->tags) as $tag) {
                 if (empty($tag)) {
                     continue;

htdocs/lib/collection.php

@@ -166,7 +166,8 @@ class Collection {
 
         if (isset($this->tags)) {
             delete_records('collection_tag', 'collection', $this->get('id'));
-            foreach ($this->get_tags() as $tag) {
+            $tags = check_case_sensitive($this->get_tags(), 'collection_tag');
+            foreach ($tags as $tag) {
                 //truncate the tag before insert it into the database
                 $tag = substr($tag, 0, 128);
                 insert_record('collection_tag', (object)array( 'collection' => $this->get('id'), 'tag' => $tag));

htdocs/lib/mahara.php

@@ -3250,3 +3250,26 @@ function generate_csv($data, $csvfields) {
     }
     return $csv;
 }
+
+/**
+ * Check to make sure table is case sensitive (currently only for MySql)
+ * If it is not then reduce supplied array to a case insensitive version
+ * Preserving the first occurance of any duplicates.
+ * E.g. 'Test,test,cat,TEST,CAT,Cat' will return 'Test,cat'
+ *
+ * @param array     Array of case senstive strings
+ * @param string    Name of table
+ *
+ * @return array    Array of strings
+ */
+function check_case_sensitive($a, $table) {
+    if (is_mysql()) {
+        $db = get_config('dbname');
+        $result = recordset_to_array(get_recordset_sql("SHOW TABLE STATUS IN `$db` WHERE Name = ?", array($table)));
+        if (preg_match('/_ci/', $result[0]->Collation)) {
+            $b = array_unique(array_map('strtolower', $a));
+            $a = array_intersect_key($a, array_flip(array_keys($b)));
+        }
+    }
+    return $a;
+}

htdocs/lib/view.php

@@ -673,6 +673,7 @@ class View {
         }
 
         if (isset($this->tags)) {
+            $this->tags = check_case_sensitive($this->tags, 'view_tag');
             delete_records('view_tag', 'view', $this->get('id'));
             foreach ($this->get_tags() as $tag) {
                 //truncate the tag before insert it into the database