1 files changed, 294 insertions, 0 deletions
diff --git a/engine/lib/pageowner.php b/engine/lib/pageowner.php
new file mode 100644
index 000000000..94765feee
--- /dev/null
+++ b/engine/lib/pageowner.php
@@ -0,0 +1,294 @@
+<?php
+/**
+ * Elgg page owner library
+ * Contains functions for managing page ownership and context
+ *
+ * @package Elgg.Core
+ * @subpackage PageOwner
+ */
+
+/**
+ * Gets the guid of the entity that owns the current page.
+ *
+ * @param int $guid Optional parameter used by elgg_set_page_owner_guid().
+ *
+ * @return int The current page owner guid (0 if none).
+ * @since 1.8.0
+ */
+function elgg_get_page_owner_guid($guid = 0) {
+	static $page_owner_guid;
+
+	if ($guid) {
+		$page_owner_guid = $guid;
+	}
+
+	if (isset($page_owner_guid)) {
+		return $page_owner_guid;
+	}
+
+	// return guid of page owner entity
+	$guid = elgg_trigger_plugin_hook('page_owner', 'system', NULL, 0);
+
+	$page_owner_guid = $guid;
+
+	return $guid;
+}
+
+/**
+ * Gets the owner entity for the current page.
+ *
+ * @note Access is disabled when getting the page owner entity.
+ *
+ * @return ElggEntity|false The current page owner or false if none.
+ *
+ * @since 1.8.0
+ */
+function elgg_get_page_owner_entity() {
+	$guid = elgg_get_page_owner_guid();
+	if ($guid > 0) {
+		$ia = elgg_set_ignore_access(true);
+		$owner = get_entity($guid);
+		elgg_set_ignore_access($ia);
+
+		return $owner;
+	}
+
+	return false;
+}
+
+/**
+ * Set the guid of the entity that owns this page
+ *
+ * @param int $guid The guid of the page owner
+ * @return void
+ * @since 1.8.0
+ */
+function elgg_set_page_owner_guid($guid) {
+	elgg_get_page_owner_guid($guid);
+}
+
+/**
+ * Sets the page owner based on request
+ *
+ * Tries to figure out the page owner by looking at the URL or a request
+ * parameter. The request parameters used are 'username' and 'owner_guid'. If
+ * the page request is going through the page handling system, this function
+ * attempts to figure out the owner if the url fits the patterns of:
+ *   <handler>/owner/<username>
+ *   <handler>/friends/<username>
+ *   <handler>/view/<entity guid>
+ *   <handler>/add/<container guid>
+ *   <handler>/edit/<entity guid>
+ *   <handler>/group/<group guid>
+ *
+ * @note Access is disabled while finding the page owner for the group gatekeeper functions.
+ *
+ *
+ * @param string $hook        'page_owner'
+ * @param string $entity_type 'system'
+ * @param int    $returnvalue Previous function's return value
+ * @param array  $params      no parameters
+ *
+ * @return int GUID
+ * @access private
+ */
+function default_page_owner_handler($hook, $entity_type, $returnvalue, $params) {
+
+	if ($returnvalue) {
+		return $returnvalue;
+	}
+
+	$ia = elgg_set_ignore_access(true);
+
+	$username = get_input("username");
+	if ($username) {
+		// @todo using a username of group:<guid> is deprecated
+		if (substr_count($username, 'group:')) {
+			preg_match('/group\:([0-9]+)/i', $username, $matches);
+			$guid = $matches[1];
+			if ($entity = get_entity($guid)) {
+				elgg_set_ignore_access($ia);
+				return $entity->getGUID();
+			}
+		}
+
+		if ($user = get_user_by_username($username)) {
+			return $user->getGUID();
+		}
+	}
+
+	$owner = get_input("owner_guid");
+	if ($owner) {
+		if ($user = get_entity($owner)) {
+			elgg_set_ignore_access($ia);
+			return $user->getGUID();
+		}
+	}
+
+	// ignore root and query
+	$uri = current_page_url();
+	$path = str_replace(elgg_get_site_url(), '', $uri);
+	$path = trim($path, "/");
+	if (strpos($path, "?")) {
+		$path = substr($path, 0, strpos($path, "?"));
+	}
+
+	// @todo feels hacky
+	if (get_input('page', FALSE)) {
+		$segments = explode('/', $path);
+		if (isset($segments[1]) && isset($segments[2])) {
+			switch ($segments[1]) {
+				case 'owner':
+				case 'friends':
+					$user = get_user_by_username($segments[2]);
+					if ($user) {
+						elgg_set_ignore_access($ia);
+						return $user->getGUID();
+					}
+					break;
+				case 'view':
+				case 'edit':
+					$entity = get_entity($segments[2]);
+					if ($entity) {
+						elgg_set_ignore_access($ia);
+						return $entity->getContainerGUID();
+					}
+					break;
+				case 'add':
+				case 'group':
+					$entity = get_entity($segments[2]);
+					if ($entity) {
+						elgg_set_ignore_access($ia);
+						return $entity->getGUID();
+					}
+					break;
+			}
+		}
+	}
+
+	elgg_set_ignore_access($ia);
+}
+
+/**
+ * Sets the page context
+ *
+ * Views can modify their output based on the local context. You may want to
+ * display a list of blogs on a blog page or in a small widget. The rendered
+ * output could be different for those two contexts ('blog' vs 'widget').
+ *
+ * Pages that pass through the page handling system set the context to the
+ * first string after the root url. Example: http://example.org/elgg/bookmarks/ 
+ * results in the initial context being set to 'bookmarks'.
+ *
+ * The context is a stack so that for a widget on a profile, the context stack
+ * may contain first 'profile' and then 'widget'.
+ *
+ * If no context was been set, the default context returned is 'main'.
+ *
+ * @warning The context is not available until the page_handler runs (after
+ * the 'init, system' event processing has completed).
+ *
+ * @param string $context The context of the page
+ * @return bool
+ * @since 1.8.0
+ */
+function elgg_set_context($context) {
+	global $CONFIG;
+
+	$context = trim($context);
+
+	if (empty($context)) {
+		return false;
+	}
+
+	$context = strtolower($context);
+
+	array_pop($CONFIG->context);
+	array_push($CONFIG->context, $context);
+
+	return true;
+}
+
+/**
+ * Get the current context.
+ *
+ * Since context is a stack, this is equivalent to a peek.
+ *
+ * @return string|NULL
+ * @since 1.8.0
+ */
+function elgg_get_context() {
+	global $CONFIG;
+
+	if (!$CONFIG->context) {
+		return null;
+	}
+
+	return $CONFIG->context[count($CONFIG->context) - 1];
+}
+
+/**
+ * Push a context onto the top of the stack
+ *
+ * @param string $context The context string to add to the context stack
+ * @return void
+ * @since 1.8.0
+ */
+function elgg_push_context($context) {
+	global $CONFIG;
+
+	array_push($CONFIG->context, $context);
+}
+
+/**
+ * Removes and returns the top context string from the stack
+ *
+ * @return string|NULL
+ * @since 1.8.0
+ */
+function elgg_pop_context() {
+	global $CONFIG;
+
+	return array_pop($CONFIG->context);
+}
+
+/**
+ * Check if this context exists anywhere in the stack
+ *
+ * This is useful for situations with more than one element in the stack. For
+ * example, a widget has a context of 'widget'. If a widget view needs to render
+ * itself differently based on being on the dashboard or profile pages, it
+ * can check the stack.
+ *
+ * @param string $context The context string to check for
+ * @return bool
+ * @since 1.8.0
+ */
+function elgg_in_context($context) {
+	global $CONFIG;
+
+	return in_array($context, $CONFIG->context);
+}
+
+/**
+ * Initializes the page owner functions
+ *
+ * @note This is on the 'boot, system' event so that the context is set up quickly.
+ *
+ * @return void
+ * @access private
+ */
+function page_owner_boot() {
+	
+	elgg_register_plugin_hook_handler('page_owner', 'system', 'default_page_owner_handler');
+
+	// Bootstrap the context stack by setting its first entry to the handler.
+	// This is the first segment of the URL and the handler is set by the rewrite rules.
+	// @todo this does not work for actions
+	$handler = get_input('handler', FALSE);
+	if ($handler) {
+		elgg_set_context($handler);
+	}
+}
+
+elgg_register_event_handler('boot', 'system', 'page_owner_boot');