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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_CHROMEOS_DRIVE_FILE_SYSTEM_TRUNCATE_OPERATION_H_
      6 #define CHROME_BROWSER_CHROMEOS_DRIVE_FILE_SYSTEM_TRUNCATE_OPERATION_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/memory/ref_counted.h"
     10 #include "base/memory/scoped_ptr.h"
     11 #include "base/memory/weak_ptr.h"
     12 #include "chrome/browser/chromeos/drive/file_errors.h"
     13 
     14 namespace base {
     15 class FilePath;
     16 class SequencedTaskRunner;
     17 }  // namespace base
     18 
     19 namespace drive {
     20 
     21 class JobScheduler;
     22 class ResourceEntry;
     23 
     24 namespace internal {
     25 class FileCache;
     26 class ResourceMetadata;
     27 }  // namespace internal
     28 
     29 namespace file_system {
     30 
     31 class OperationObserver;
     32 class DownloadOperation;
     33 
     34 // This class encapsulates the drive Truncate function. It is responsible for
     35 // fetching the content from the Drive server if necessary, truncating the
     36 // file content actually, and then notifying the file is locally modified and
     37 // that it is necessary to upload the file to the server.
     38 class TruncateOperation {
     39  public:
     40   TruncateOperation(base::SequencedTaskRunner* blocking_task_runner,
     41                     OperationObserver* observer,
     42                     JobScheduler* scheduler,
     43                     internal::ResourceMetadata* metadata,
     44                     internal::FileCache* cache,
     45                     const base::FilePath& temporary_file_directory);
     46   ~TruncateOperation();
     47 
     48   // Performs the truncate operation on the file at drive path |file_path| to
     49   // |length| bytes. Invokes |callback| when finished with the result of the
     50   // operation. |callback| must not be null.
     51   void Truncate(const base::FilePath& file_path,
     52                 int64 length,
     53                 const FileOperationCallback& callback);
     54  private:
     55   // Part of Truncate(). Called after EnsureFileDownloadedByPath() is complete.
     56   void TruncateAfterEnsureFileDownloadedByPath(
     57       const base::FilePath& file_path,
     58       int64 length,
     59       const FileOperationCallback& callback,
     60       FileError error,
     61       const base::FilePath& local_file_path,
     62       scoped_ptr<ResourceEntry> resource_entry);
     63 
     64   // Part of Truncate(). Called after TruncateOnBlockingPool() is complete.
     65   void TruncateAfterTruncateOnBlockingPool(
     66       const std::string& resource_id,
     67       const FileOperationCallback& callback,
     68       FileError error);
     69 
     70   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
     71   OperationObserver* observer_;
     72   internal::FileCache* cache_;
     73 
     74   scoped_ptr<DownloadOperation> download_operation_;
     75 
     76   // Note: This should remain the last member so it'll be destroyed and
     77   // invalidate the weak pointers before any other members are destroyed.
     78   base::WeakPtrFactory<TruncateOperation> weak_ptr_factory_;
     79   DISALLOW_COPY_AND_ASSIGN(TruncateOperation);
     80 };
     81 
     82 }  // namespace file_system
     83 }  // namespace drive
     84 
     85 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_FILE_SYSTEM_TRUNCATE_OPERATION_H_
     86