From d669160891000b33fbdf51b816f2655ce0c694d2 Mon Sep 17 00:00:00 2001
From: skodak <skodak>
Date: Tue, 28 Oct 2008 12:14:09 +0000
Subject: [PATCH] MDL-15070 dml: recordset rewinding now forbidden - not all
 databases support it, sorry

---
 lib/dml/adodb_moodle_recordset.php         |  4 ----
 lib/dml/moodle_recordset.php               |  7 +++++--
 lib/dml/mysqli_native_moodle_recordset.php |  4 ----
 lib/dml/pdo_moodle_recordset.php           |  7 -------
 lib/dml/pgsql_native_moodle_recordset.php  |  4 ----
 user/index.php                             | 14 ++++++--------
 6 files changed, 11 insertions(+), 29 deletions(-)

diff --git a/lib/dml/adodb_moodle_recordset.php b/lib/dml/adodb_moodle_recordset.php
index 0b325ea7341..81a44ecbe2c 100644
--- a/lib/dml/adodb_moodle_recordset.php
+++ b/lib/dml/adodb_moodle_recordset.php
@@ -27,10 +27,6 @@ class adodb_moodle_recordset extends moodle_recordset {
         $this->rs->MoveNext();
     }
 
-    public function rewind() {
-        $this->rs->MoveFirst();
-    }
-
     public function valid() {
         return !$this->rs->EOF;
     }
diff --git a/lib/dml/moodle_recordset.php b/lib/dml/moodle_recordset.php
index 4c18fe532d6..8aa6f76ab50 100644
--- a/lib/dml/moodle_recordset.php
+++ b/lib/dml/moodle_recordset.php
@@ -31,10 +31,13 @@ abstract class moodle_recordset implements Iterator {
     //public abstract function next();
 
     /**
-     * Revinds back to the first row
+     * Revinds are not supported!
      * @return void
      */
-    //public abstract function rewind();
+    public function rewind() {
+        // no seeking, sorry - let's ignore it ;-)
+        return;
+    }
 
     /**
      * Did we reach the end?
diff --git a/lib/dml/mysqli_native_moodle_recordset.php b/lib/dml/mysqli_native_moodle_recordset.php
index 7917676a4c9..13e7577722d 100644
--- a/lib/dml/mysqli_native_moodle_recordset.php
+++ b/lib/dml/mysqli_native_moodle_recordset.php
@@ -40,10 +40,6 @@ class mysqli_native_moodle_recordset extends moodle_recordset {
         $this->current = $this->fetch_next();
     }
 
-    public function rewind() {
-        // we can not seek, sorry - let's ignore it ;-)
-    }
-
     public function valid() {
         return !empty($this->current);
     }
diff --git a/lib/dml/pdo_moodle_recordset.php b/lib/dml/pdo_moodle_recordset.php
index 3122b7035c4..aa65dcc3f42 100644
--- a/lib/dml/pdo_moodle_recordset.php
+++ b/lib/dml/pdo_moodle_recordset.php
@@ -34,13 +34,6 @@ class pdo_moodle_recordset extends moodle_recordset {
         return $this->fields !== false;
     }
 
-    public function rewind() {
-        $this->fields = $this->sth->fetch();
-        if ($this->fields) {
-            $this->rowCount = 0;
-        }
-    }
-
     public function valid() {
         if($this->rowCount < 0) {
             $this->rewind();
diff --git a/lib/dml/pgsql_native_moodle_recordset.php b/lib/dml/pgsql_native_moodle_recordset.php
index 65d81a0e643..eb2d5261766 100644
--- a/lib/dml/pgsql_native_moodle_recordset.php
+++ b/lib/dml/pgsql_native_moodle_recordset.php
@@ -58,10 +58,6 @@ class pgsql_native_moodle_recordset extends moodle_recordset {
         $this->current = $this->fetch_next();
     }
 
-    public function rewind() {
-        // we can not seek, sorry - let's ignore it ;-)
-    }
-
     public function valid() {
         return !empty($this->current);
     }
diff --git a/user/index.php b/user/index.php
index a02da92b58c..07133245118 100644
--- a/user/index.php
+++ b/user/index.php
@@ -531,16 +531,14 @@
     // of rows anyway. On a large course it will explode badly...
     //
     if ($mode===MODE_ENROLDETAILS) {
-        $userids = array();
-
-        foreach ($userlist as $user) {
-            $userids[] = $user->id;
+        if ($context->id != $frontpagectx->id) {
+            $userids = $DB->get_fieldset_sql("SELECT DISTINCT u.id $from $where $wheresearch $sort", $params,
+                                             $table->get_page_start(),  $table->get_page_size());
+        } else {
+            $userids = $DB->get_fieldset_sql("SELECT u.id $from $where $wheresearch $sort", $params,
+                                             $table->get_page_start(),  $table->get_page_size());
         }
         $userlist_extra = get_participants_extra($userids, $avoidroles, $course, $context);
-
-        // Only Oracle cannot seek backwards
-        // and must re-query...
-        $userlist->rewind();
     }
 
     if ($context->id == $frontpagectx->id) {