From c6c9b4facacbadf91b3fd57888f2003e6f79ce48 Mon Sep 17 00:00:00 2001
From: tjhunt <tjhunt>
Date: Fri, 9 Jan 2009 06:16:52 +0000
Subject: [PATCH] accesslib: MDL-17626 delete the context whenever a block is
 deleted. This includes a new helper function blocks_delete_all_on_page.

---
 backup/restorelib.php |  2 +-
 lib/blocklib.php      | 21 ++++++++++++++++++++-
 mod/chat/lib.php      |  2 +-
 mod/lesson/lib.php    |  2 +-
 mod/quiz/lib.php      |  2 +-
 5 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/backup/restorelib.php b/backup/restorelib.php
index 472d7d7a4e2..0a26a75f5ad 100644
--- a/backup/restorelib.php
+++ b/backup/restorelib.php
@@ -824,7 +824,7 @@ define('RESTORE_GROUPS_GROUPINGS', 3);
         global $CFG;
         $status = true;
 
-        delete_records('block_instance', 'pageid', $restore->course_id, 'pagetype', PAGE_COURSE_VIEW);
+        blocks_delete_all_on_page(PAGE_COURSE_VIEW, $restore->course_id);
         if (empty($backup_block_format)) {     // This is a backup from Moodle < 1.5
             if (empty($blockinfo)) {
                 // Looks like it's from Moodle < 1.3. Let's give the course default blocks...
diff --git a/lib/blocklib.php b/lib/blocklib.php
index e178e1858b9..6fe517745ef 100644
--- a/lib/blocklib.php
+++ b/lib/blocklib.php
@@ -208,6 +208,7 @@ function blocks_delete_instance($instance,$pinned=false) {
     } else {
         // Now kill the db record;
         delete_records('block_instance', 'id', $instance->id);
+        delete_context(CONTEXT_BLOCK, $instance->id);
         // And now, decrement the weight of all blocks after this one
         execute_sql('UPDATE '.$CFG->prefix.'block_instance SET weight = weight - 1 WHERE pagetype = \''.$instance->pagetype.
                     '\' AND pageid = '.$instance->pageid.' AND position = \''.$instance->position.
@@ -972,6 +973,24 @@ function blocks_print_adminblock(&$page, &$pageblocks) {
     }
 }
 
+/**
+ * Delete all the blocks from a particular page.
+ *
+ * @param string $pagetype the page type.
+ * @param integer $pageid the page id.
+ * @return success of failure.
+ */
+function blocks_delete_all_on_page($pagetype, $pageid) {
+    if ($instances = get_records_select('block_instance', 'pageid = ' . $pageid . ' AND pagetype = ' . $pagetype)) {
+        foreach ($instances as $instance) {
+            delete_context(CONTEXT_BLOCK, $instance->id); // Ingore any failures here.
+        }
+    }
+    return delete_records('block_instance', 'pageid', $pageid, 'pagetype', $pagetype);
+}
+
+// Dispite what this function is called, it seems to be mostly used to populate
+// the default blocks when a new course (or whatever) is created.
 function blocks_repopulate_page($page) {
     global $CFG;
 
@@ -1003,7 +1022,7 @@ function blocks_repopulate_page($page) {
     // indexed and the indexes match, so we can work straight away... but CAREFULLY!
 
     // Ready to start creating block instances, but first drop any existing ones
-    delete_records('block_instance', 'pageid', $page->get_id(), 'pagetype', $page->get_type());
+    blocks_delete_all_on_page($page->get_type(), $page->get_id());
 
     // Here we slyly count $posblocks and NOT $positions. This can actually make a difference
     // if the textual representation has undefined slots in the end. So we only work with as many
diff --git a/mod/chat/lib.php b/mod/chat/lib.php
index de1fc5c9133..1b0f6bd46e0 100644
--- a/mod/chat/lib.php
+++ b/mod/chat/lib.php
@@ -126,7 +126,7 @@ function chat_delete_instance($id) {
 
     $pagetypes = page_import_types('mod/chat/');
     foreach($pagetypes as $pagetype) {
-        if(!delete_records('block_instance', 'pageid', $chat->id, 'pagetype', $pagetype)) {
+        if(!blocks_delete_all_on_page($pagetype, $chat->id)) {
             $result = false;
         }
     }
diff --git a/mod/lesson/lib.php b/mod/lesson/lib.php
index cdf71bb8acf..9c36b08db9d 100644
--- a/mod/lesson/lib.php
+++ b/mod/lesson/lib.php
@@ -107,7 +107,7 @@ function lesson_delete_instance($id) {
     }
     $pagetypes = page_import_types('mod/lesson/');
     foreach ($pagetypes as $pagetype) {
-        if (!delete_records('block_instance', 'pageid', $lesson->id, 'pagetype', $pagetype)) {
+        if (!blocks_delete_all_on_page($pagetype, $lesson->id)) {
             $result = false;
         }
     }
diff --git a/mod/quiz/lib.php b/mod/quiz/lib.php
index 05bc11627dc..3bb465e46ad 100644
--- a/mod/quiz/lib.php
+++ b/mod/quiz/lib.php
@@ -158,7 +158,7 @@ function quiz_delete_instance($id) {
 
     $pagetypes = page_import_types('mod/quiz/');
     foreach($pagetypes as $pagetype) {
-        if(!delete_records('block_instance', 'pageid', $quiz->id, 'pagetype', $pagetype)) {
+        if(!blocks_delete_all_on_page($pagetype, $quiz->id)) {
             $result = false;
         }
     }