files: Stop computing a directory size when selected

Selecting a directory was expensive because Files.app computed the size of
a directory by recursively visiting all the sub directories and summing up
sizes of all files underneath. This is super expensive with a large directory
tree with thousands of directories and files underneath.

BUG=179000
TEST=Select a directory, size is not shown. Select a file, size is shown.


Review URL: https://chromiumcodereview.appspot.com/12379037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@185527 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 21 insertions, 15 deletions

diff --git a/chrome/browser/resources/file_manager/js/file_selection.js b/chrome/browser/resources/file_manager/js/file_selection.js
index ca78735..8796461 100644
--- a/chrome/browser/resources/file_manager/js/file_selection.js
+++ b/chrome/browser/resources/file_manager/js/file_selection.js
@@ -106,23 +106,25 @@ FileSelection.prototype.computeBytes = function(callback) {
     maybeDone();
   }.bind(this);
 
-  var onEntry = function(entry) {
-    if (entry) {
-      if (entry.isFile) {
-        this.showBytes |= !FileType.isHosted(entry);
-        pendingMetadataCount++;
-        this.fileManager_.metadataCache_.get(entry, 'filesystem', onProps);
-      }
-    } else {
-      countdown--;
-      maybeDone();
-    }
-    return !this.cancelled_;
-  }.bind(this);
-
   for (var index = 0; index < this.entries.length; index++) {
-    util.forEachEntryInTree(this.entries[index], onEntry);
+    if (this.cancelled_)
+      break;
+
+    var entry = this.entries[index];
+    if (entry.isFile) {
+      this.showBytes |= !FileType.isHosted(entry);
+      pendingMetadataCount++;
+      this.fileManager_.metadataCache_.get(entry, 'filesystem', onProps);
+    } else if (entry.isDirectory) {
+      // Don't compute the directory size as it's expensive.
+      // crbug.com/179073.
+      this.showBytes = false;
+      countdown = 0;
+      break;
+    }
+    countdown--;
   }
+  maybeDone();
 };
 
 /**
diff --git a/chrome/browser/resources/file_manager/js/util.js b/chrome/browser/resources/file_manager/js/util.js
index 90c4f06..97999b3a 100644
--- a/chrome/browser/resources/file_manager/js/util.js
+++ b/chrome/browser/resources/file_manager/js/util.js
@@ -198,6 +198,8 @@ util.recurseAndResolveEntries = function(entries, recurse, successCallback) {
 
 /**
  * Utility function to invoke callback once for each entry in dirEntry.
+ * callback is called with 'null' after all entries are visited to indicate
+ * the end of the directory scan.
  *
  * @param {DirectoryEntry} dirEntry The directory entry to enumerate.
  * @param {function(Entry)} callback The function to invoke for each entry in
@@ -643,6 +645,8 @@ util.traverseTree = function(root, callback, max_depth, opt_filter) {
 
 /**
  * Traverses a tree up to a certain depth, and calls a callback for each entry.
+ * callback is called with 'null' after all entries are visited to indicate
+ * the end of the traversal.
  * @param {FileEntry} root Root entry.
  * @param {function(Entry):boolean} callback The callback is called for each
  *     entry, and then once with null passed. If callback returns false once,