Patch for tickets #1428 and #1760

Create the concept of a Photo_Display_Context.  If the user is browsing a dynamic album (i.e. tags) and chooses to
look at an image in that album.  The display of the image happens correctly, but the 'next' and 'previous' buttons
are no longer consistent.  When one of these is clicked, Gallery  will open the adjacent image in the actuall album,
not the dynamic album.

2 files changed, 115 insertions, 0 deletions

diff --git a/modules/gallery/libraries/Display_Context.php b/modules/gallery/libraries/Display_Context.php
new file mode 100644
index 00000000..5054cffb
--- /dev/null
+++ b/modules/gallery/libraries/Display_Context.php
@@ -0,0 +1,71 @@
+<?php defined("SYSPATH") or die("No direct script access.");
+/**
+ * Gallery - a web based photo album viewer and editor
+ * Copyright (C) 2000-2011 Bharat Mediratta
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+abstract class Display_Context_Core {
+  private $_display_context_name;
+  private $_data;
+
+  static function factory($display_context_name=null) {
+    if (empty($display_context_name)) {
+      $display_context_id = Session::instance()->get("display_context_id", "");
+      $context = Cache::instance()->get($display_context_id, null);
+      $context = empty($context) ? new Item_Display_Context() : unserialize($context);
+    } else {
+      $class_prefix = ucfirst(strtolower($display_context_name));
+      $class_name = "{$class_prefix}_Display_Context";
+      $context = new $class_name();
+    }
+
+    return $context;
+  }
+
+  protected function __construct($display_context_name) {
+    // $this->reset($display_context_name);
+    $this->_data = array();
+    $this->_display_context_name = $display_context_name;
+  }
+
+  final function get($key) {
+    return empty($this->_data[$key]) ? null : $this->_data[$key];
+  }
+
+  final function set($key, $value=null) {
+    if (is_array($key)) {
+      if ((array)$key == $key) {
+        $this->_data = array_merge($this->_data, $key);
+      } else {
+        $this->_data = array_merge($this->_data, array_fill_keys($key, $value));
+      }
+    } else {
+      $this->_data[$key] = $value;
+    }
+    return $this;
+  }
+
+  final function save() {
+    $context_data = serialize($this);
+    $display_context_id = "display_context_" . md5($context_data);
+    Session::instance()->set("display_context_id", $display_context_id);
+    Cache::instance()->set($display_context_id, $context_data);
+    return $this;
+  }
+
+  abstract function display_context($item);
+}
diff --git a/modules/gallery/libraries/Item_Display_Context.php b/modules/gallery/libraries/Item_Display_Context.php
new file mode 100644
index 00000000..d0562790
--- /dev/null
+++ b/modules/gallery/libraries/Item_Display_Context.php
@@ -0,0 +1,44 @@
+<?php defined("SYSPATH") or die("No direct script access.");
+/**
+ * Gallery - a web based photo album viewer and editor
+ * Copyright (C) 2000-2011 Bharat Mediratta
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+class Item_Display_Context_Core extends Display_Context {
+  protected function __construct() {
+    parent::__construct("item");
+  }
+
+  function display_context($item) {
+    $where = array(array("type", "!=", "album"));
+    $position = item::get_position($item, $where);
+    if ($position > 1) {
+      list ($previous_item, $ignore, $next_item) =
+        $item->parent()->viewable()->children(3, $position - 2, $where);
+    } else {
+      $previous_item = null;
+      list ($next_item) = $item->parent()->viewable()->children(1, $position, $where);
+   }
+
+    return array("position" =>$position,
+                 "previous_item" => $previous_item,
+                 "next_item" =>$next_item,
+                 "sibling_count" => $item->parent()->viewable()->children_count($where),
+                 "parents" => $item->parents()->as_array(),
+                 "breadcrumbs" => Breadcrumb::array_from_item_parents($item));
+  }
+}