Run recursive file operations sequentially.

storage/browser/fileapi/recursive_operation_delegate.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef STORAGE_BROWSER_FILEAPI_RECURSIVE_OPERATION_DELEGATE_H_
 #define STORAGE_BROWSER_FILEAPI_RECURSIVE_OPERATION_DELEGATE_H_
 
 #include <queue>
 #include <stack>
 
@@ skipping 56 matching lines @@
   // This will call ProcessFile and ProcessDirectory on each file or directory.
   //
   // First, this tries to call ProcessFile with |root| regardless whether it is
   // actually a file or a directory. If it is a directory, ProcessFile should
   // return File::FILE_NOT_A_FILE.
   //
   // For each directory, the recursive operation works as follows:
   // ProcessDirectory is called first for the directory.
   // Then the directory contents are read (to obtain its sub directories and
   // files in it).
-  // ProcessFile is called for found files. This may run in parallel.
+  // ProcessFile is called for found files.
   // The same step is recursively applied to each subdirectory.
   // After all files and subdirectories in a directory are processed,
   // PostProcessDirectory is called for the directory.
   // Here is an example;
   // a_dir/ -+- b1_dir/ -+- c1_dir/ -+- d1_file
   //         |           |           |
   //         |           +- c2_file  +- d2_file
   //         |
   //         +- b2_dir/ --- e_dir/
   //         |
   //         +- b3_file
   //         |
   //         +- b4_file
   // Then traverse order is:
   // ProcessFile(a_dir) (This should return File::FILE_NOT_A_FILE).
   // ProcessDirectory(a_dir).
-  // ProcessFile(b3_file), ProcessFile(b4_file). (in parallel).
+  // ProcessFile(b3_file).
+  // ProcessFile(b4_file).
   // ProcessDirectory(b1_dir).
   // ProcessFile(c2_file)
   // ProcessDirectory(c1_dir).
-  // ProcessFile(d1_file), ProcessFile(d2_file). (in parallel).
+  // ProcessFile(d1_file).
+  // ProcessFile(d2_file).
   // PostProcessDirectory(c1_dir)
   // PostProcessDirectory(b1_dir).
   // ProcessDirectory(b2_dir)
   // ProcessDirectory(e_dir)
   // PostProcessDirectory(e_dir)
   // PostProcessDirectory(b2_dir)
   // PostProcessDirectory(a_dir)
   //
   // |error_behavior| is to specify how this behaves when an operation have
   // failed.
@@ skipping 30 matching lines @@
   void DidPostProcessDirectory(base::File::Error error);
 
   // Called when all recursive operation is done (or an error occurs).
   void Done(base::File::Error error);
 
   FileSystemContext* file_system_context_;
   StatusCallback callback_;
   std::stack<FileSystemURL> pending_directories_;
   std::stack<std::queue<FileSystemURL> > pending_directory_stack_;
   std::queue<FileSystemURL> pending_files_;
-  int inflight_operations_;
   bool canceled_;
   ErrorBehavior error_behavior_;
   bool failed_some_operations_;
 
   DISALLOW_COPY_AND_ASSIGN(RecursiveOperationDelegate);
 };
 
 }  // namespace storage
 
 #endif  // STORAGE_BROWSER_FILEAPI_RECURSIVE_OPERATION_DELEGATE_H_