accesslib: create_context() now populates the path of new contexts

... and it populates the context cache too.

Unfortunately, it needs an INSERT followed by an UPDATE. Other than
a stored procedure, I don't know how to deal with this better.

(We could save the SELECT though! that's a thought...)

OTOH, we are getting so much mileage out of the path field
that it's probably a hit we have to take in the chin and move on.

diff --git a/lib/accesslib.php b/lib/accesslib.php
index 12cc0c33329509bef7d37ab6f6df2dedf1070f6e..763d9429c6654b92f219ec15fdeac683670502af 100755 (executable)
--- a/lib/accesslib.php
+++ b/lib/accesslib.php
@@ -1969,9 +1969,12 @@ function islegacy($capabilityname) {
  * @param $level
  * @param $instanceid
  *
- * @return object newly created context (or existing one with a debug warning)
+ * @return object newly created context
  */
 function create_context($contextlevel, $instanceid) {
+
+    global $CFG;
+
     if ($contextlevel == CONTEXT_SYSTEM) {
         return create_system_context();
     }
@@ -1979,8 +1982,67 @@ function create_context($contextlevel, $instanceid) {
     $context = new object();
     $context->contextlevel = $contextlevel;
     $context->instanceid = $instanceid;
+
+    // Define $context->path based on the parent
+    // context. In other words... Who is your daddy?
+    $basepath = '/' . SYSCONTEXTID;
+
+    switch ($contextlevel) {
+        case CONTEXT_COURSECAT:
+            $sql = "SELECT ctx.path 
+                    FROM {$CFG->prefix}context           ctx
+                    JOIN {$CFG->prefix}course_categories cc
+                      ON (cc.parent=ctx.instanceid AND ctx.contextlevel=".CONTEXT_COURSECAT.")
+                    WHERE cc.id={$instanceid}";
+            if ($path = get_field_sql($sql)) {
+                $basepath = $path;
+            }
+            break;
+
+        case CONTEXT_COURSE:
+            $sql = "SELECT ctx.path 
+                    FROM {$CFG->prefix}context           ctx
+                    JOIN {$CFG->prefix}course            c
+                      ON (c.category=ctx.instanceid AND ctx.contextlevel=".CONTEXT_COURSECAT.")
+                    WHERE c.id={$instanceid} AND c.id !=" . SITEID;
+            if ($path = get_field_sql($sql)) {
+                $basepath = $path;
+            }
+            break;
+
+        case CONTEXT_MODULE:
+            $sql = "SELECT ctx.path
+                    FROM {$CFG->prefix}context           ctx
+                    JOIN {$CFG->prefix}course_modules    cm
+                      ON (cm.course=ctx.instanceid AND ctx.contextlevel=".CONTEXT_COURSE.")
+                    WHERE cm.id={$instanceid}";
+            $path = get_field_sql($sql);
+            $basepath = $path;
+            break;
+
+        case CONTEXT_BLOCK:
+            // Only non-pinned & course-page based
+            $sql = "SELECT ctx.path
+                    FROM {$CFG->prefix}context           ctx
+                    JOIN {$CFG->prefix}block_instance    bi
+                      ON (bi.pageid=ctx.instanceid AND ctx.contextlevel=".CONTEXT_COURSE.")
+                    WHERE bi.id={$instanceid} AND bi.pagetype='course-view'";
+            $path = get_field_sql($sql);
+            $basepath = $path;
+            break;
+        case CONTEXT_USER:
+            // default to basepath
+            break;
+        case CONTEXT_PERSONAL:
+            // default to basepath
+            break;
+    }
+
     if ($id = insert_record('context',$context)) {
-        $c = get_record('context','id',$id);
+        // can't set the path till we know the id!
+        set_field('context', 'path', $basepath . '/' . $id,
+                  'id', $id);
+        $c = get_context_instance_by_id($id);
         return $c;
     } else {
         debugging('Error: could not insert new context level "'.