From ad0e8b5615f4585f78ccbe27912c2545875a77f1 Mon Sep 17 00:00:00 2001
From: Dries Buytaert <dries@buytaert.net>
Date: Tue, 29 Aug 2006 08:36:14 +0000
Subject: [PATCH] - Patch #81078 by M. Plumbley: documented drupal_is_denied(),
and improved performance of drupal_is_denied().
---
includes/bootstrap.inc | 34 +++++++++++++++++++++++++++++-----
1 file changed, 29 insertions(+), 5 deletions(-)
diff --git a/includes/bootstrap.inc b/includes/bootstrap.inc
index 5d3c03ba8fa8..f52563157e6d 100644
--- a/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -597,13 +597,37 @@ function drupal_get_messages($type = NULL) {
}
/**
- * Perform an access check for a given mask and rule type. Rules are usually created via admin/user/rules page.
+ * Perform an access check for a given mask and rule type. Rules are usually
+ * created via admin/user/rules page.
+ *
+ * If any allow rule matches, access is allowed. Otherwise, if any deny rule
+ * matches, access is denied. If no rule matches, access is allowed.
+ *
+ * @param $type string
+ * Type of access to check: Allowed values are:
+ * - 'host': host name or IP address
+ * - 'mail': e-mail address
+ * - 'user': username
+ * @param $mask string
+ * String or mask to test: '_' matches any character, '%' matches any
+ * number of characters.
+ * @return bool
+ * TRUE if access is denied, FALSE if access is allowed.
*/
function drupal_is_denied($type, $mask) {
- $allow = db_fetch_object(db_query("SELECT * FROM {access} WHERE status = 1 AND type = '%s' AND LOWER('%s') LIKE LOWER(mask)", $type, $mask));
- $deny = db_fetch_object(db_query("SELECT * FROM {access} WHERE status = 0 AND type = '%s' AND LOWER('%s') LIKE LOWER(mask)", $type, $mask));
-
- return $deny && !$allow;
+ // Because this function is called for every page request, both cached
+ // and non-cached pages, we tried to optimize it as much as possible.
+ // We deny access if the only matching records in the {access} table have
+ // status 0. If any have status 1, or if there are no matching records,
+ // we allow access. So, select matching records in decreasing order of
+ // 'status', returning NOT(status) for the first. If any have status 1,
+ // they come first, and we return NOT(status) = 0 (allowed). Otherwise,
+ // if we have some with status 0, we return 1 (denied). If no matching
+ // records, we get no return from db_result, so we return (bool)NULL = 0
+ // (allowed).
+ // The use of ORDER BY / LIMIT is more efficient than "MAX(status) = 0"
+ // in PostgreSQL <= 8.0.
+ return (bool) db_result(db_query_range("SELECT NOT(status) FROM {access} WHERE type = '%s' AND LOWER('%s') LIKE LOWER(mask) ORDER BY status DESC", $type, $mask, 0, 1));
}
/**
--
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