Copy folder recursively for syncfsToLocalfs export.

chrome/browser/extensions/api/developer_private/developer_private_api.cc

Index: chrome/browser/extensions/api/developer_private/developer_private_api.cc
diff --git a/chrome/browser/extensions/api/developer_private/developer_private_api.cc b/chrome/browser/extensions/api/developer_private/developer_private_api.cc
index 1642e47f0a563d02acce615f5a858dfe6eefddbb..0e36e9e2c86a740696af4d14752264aa486121bf 100644
--- a/chrome/browser/extensions/api/developer_private/developer_private_api.cc
+++ b/chrome/browser/extensions/api/developer_private/developer_private_api.cc
@@ -834,28 +834,33 @@ void DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
     return;
   }
 
+  pendingCallbacksCount_ = 1;
+
   content::BrowserThread::PostTask(content::BrowserThread::IO, FROM_HERE,
       base::Bind(&DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
                  ReadSyncFileSystemDirectory,
-                 this, project_path));
+                 this, project_path, project_path.BaseName()));
 }
 
 void DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
-    ReadSyncFileSystemDirectory(const base::FilePath& project_path) {
+    ReadSyncFileSystemDirectory(const base::FilePath& project_path,
+                                const base::FilePath& current_path) {
   std::string origin_url(
       Extension::GetBaseURLFromExtensionId(extension_id()).spec());
   fileapi::FileSystemURL url(sync_file_system::CreateSyncableFileSystemURL(
       GURL(origin_url),
-      project_path.BaseName()));
+      current_path));
 
   context_->operation_runner()->ReadDirectory(
       url, base::Bind(&DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
-                      ReadSyncFileSystemDirectoryCb, this, project_path));
+                      ReadSyncFileSystemDirectoryCb,
+                      this, project_path, current_path));
 }
 
 void DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
     ReadSyncFileSystemDirectoryCb(
     const base::FilePath& project_path,
+    const base::FilePath& current_path,
     base::PlatformFileError status,
     const fileapi::FileSystemOperation::FileEntryList& file_list,
     bool has_more) {
@@ -865,24 +870,20 @@ void DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
     return;
   }
 
-  // Create an empty project folder if there are no files.
-  if (!file_list.size()) {
-    content::BrowserThread::PostTask(content::BrowserThread::FILE, FROM_HERE,
-      base::Bind(&DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
-                     CreateFolderAndSendResponse,
-                 this,
-                 project_path));
-    return;
-  }
-
-  pendingCallbacksCount_ = file_list.size();
+  pendingCallbacksCount_ += file_list.size();

[miket_OOO, 2013/06/12 19:39:24]

This is pretty confusing. You're adding N to pendingCallbacksCount_, but only
decrementing it once later in this method. There seems to be some kind of
recursion going on, but it's not at all obvious how it works.

Can you add more comments to explain it?

[Gaurav, 2013/06/21 22:11:00]

Done.

 
   for (size_t i = 0; i < file_list.size(); ++i) {
+    if (file_list[i].is_directory) {
+      ReadSyncFileSystemDirectory(project_path.Append(file_list[i].name),
+                                  current_path.Append(file_list[i].name));
+      continue;

[miket_OOO, 2013/06/12 19:39:24]

This is a good example of why it's confusing. It seems like you're adding the
whole file list size, but then doing the recursive call (the only thing that
subtracts from pendingCallbacksCount_) only once for each directory. What if
something in the list isn't a directory? Won't pendingCallbacksCount_ stay
positive forever? Code comments here would help.

[Gaurav, 2013/06/21 22:11:00]

Done.

+    }
+
     std::string origin_url(
         Extension::GetBaseURLFromExtensionId(extension_id()).spec());
     fileapi::FileSystemURL url(sync_file_system::CreateSyncableFileSystemURL(
         GURL(origin_url),
-        project_path.BaseName().Append(file_list[i].name)));
+        current_path.Append(file_list[i].name)));
     base::FilePath target_path = project_path;
     target_path = target_path.Append(file_list[i].name);
 
@@ -893,19 +894,16 @@ void DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
                 SnapshotFileCallback,
             this,
             target_path));
-  }
-}
 
-void DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
-    CreateFolderAndSendResponse(const base::FilePath& project_path) {
-  if (!(success_ = file_util::CreateDirectory(project_path))) {
-    SetError("Error in copying files from sync filesystem.");
   }
-  content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
-      base::Bind(&DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
-                     SendResponse,
-                 this,
-                 success_));
+  pendingCallbacksCount_--;
+  if (!pendingCallbacksCount_) {
+    content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+        base::Bind(&DeveloperPrivateExportSyncfsFolderToLocalfsFunction::
+                       SendResponse,
+                   this,
+                   success_));
+  }
 }
 
 void DeveloperPrivateExportSyncfsFolderToLocalfsFunction::SnapshotFileCallback(