1 files changed, 78 insertions, 4 deletions
diff --git a/chrome/browser/resources/bookmark_manager/js/bmm.js b/chrome/browser/resources/bookmark_manager/js/bmm.js
index 24c4ad0..73cefa6 100644
--- a/chrome/browser/resources/bookmark_manager/js/bmm.js
+++ b/chrome/browser/resources/bookmark_manager/js/bmm.js
@@ -3,10 +3,15 @@
 // found in the LICENSE file.
 
 cr.define('bmm', function() {
-  function isFolder(bookmarkNode) {
-    return !bookmarkNode.url;
-  }
+  const TreeIterator = bmm.TreeIterator;
+  const Promise = cr.Promise;
 
+  /**
+   * Whether a node contains another node.
+   * @param {!BookmarkTreeNode} parent
+   * @param {!BookmarkTreeNode} descendant
+   * @return {boolean} Whether the parent contains the descendant.
+   */
   function contains(parent, descendant) {
     if (descendant.parentId == parent.id)
       return true;
@@ -17,8 +22,77 @@ cr.define('bmm', function() {
     return this.contains(parent, parentTreeItem.bookmarkNode);
   }
 
+  /**
+   * @param {!BookmarkTreeNode} node The node to test.
+   * @return {boolean} Whether a bookmark node is a folder.
+   */
+  function isFolder(node) {
+    return !('url' in node);
+  }
+
+  var loadingPromise;
+
+  /**
+   * Loads the entire bookmark tree and returns a {@code cr.Promise} that will
+   * be fulfilled when done. This reuses multiple loads so that we never load
+   * more than one tree at the same time.
+   * @return {!cr.Promise} The future promise for the load.
+   */
+  function loadTree() {
+    var p = new Promise;
+    if (!loadingPromise) {
+      loadingPromise = new Promise;
+      chrome.bookmarks.getTree(function(nodes) {
+        loadingPromise.value = nodes[0];
+        loadingPromise = null;
+      });
+    }
+    loadingPromise.addListener(function(n) {
+      p.value = n;
+    });
+    return p;
+  }
+
+  /**
+   * Helper function for {@code loadSubtree}. This does an in order search of
+   * the tree.
+   * @param {!BookmarkTreeNode} node The node to start searching at.
+   * @param {string} id The ID of the node to find.
+   * @return {BookmarkTreeNode} The found node or null if not found.
+   */
+  function findNode(node, id) {
+    var it = new TreeIterator(node);
+    var n;
+    while (it.moveNext()) {
+      n = it.current;
+      if (n.id == id)
+        return n;
+    }
+    return null;
+  }
+
+  /**
+   * Loads a subtree of the bookmark tree and returns a {@code cr.Promise} that
+   * will be fulfilled when done. This reuses multiple loads so that we never
+   * load more than one tree at the same time. (This actually loads the entire
+   * tree but it will only return the relevant subtree in the value of the
+   * future promise.)
+   * @return {!cr.Promise} The future promise for the load.
+   */
+  function loadSubtree(id) {
+    var p = new Promise;
+    var lp = loadTree();
+    lp.addListener(function(tree) {
+      var node = findNode(tree, id);
+      p.value = node || Error('Failed to load subtree ' + id);
+    });
+    return p;
+  }
+
   return {
+    contains: contains,
     isFolder: isFolder,
-    contains: contains
+    loadSubtree: loadSubtree,
+    loadTree: loadTree
   };
 });