components/drive/file_system/truncate_operation.h

   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 COMPONENTS_DRIVE_FILE_SYSTEM_TRUNCATE_OPERATION_H_
   6 #define COMPONENTS_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 "base/threading/thread_checker.h"
  13 #include "components/drive/file_errors.h"
  14
  15 namespace base {
  16 class FilePath;
  17 class SequencedTaskRunner;
  18 }  // namespace base
  19
  20 namespace drive {
  21
  22 class JobScheduler;
  23 class ResourceEntry;
  24
  25 namespace internal {
  26 class FileCache;
  27 class ResourceMetadata;
  28 }  // namespace internal
  29
  30 namespace file_system {
  31
  32 class OperationDelegate;
  33 class DownloadOperation;
  34
  35 // This class encapsulates the drive Truncate function. It is responsible for
  36 // fetching the content from the Drive server if necessary, truncating the
  37 // file content actually, and then notifying the file is locally modified and
  38 // that it is necessary to upload the file to the server.
  39 class TruncateOperation {
  40  public:
  41   TruncateOperation(base::SequencedTaskRunner* blocking_task_runner,
  42                     OperationDelegate* delegate,
  43                     JobScheduler* scheduler,
  44                     internal::ResourceMetadata* metadata,
  45                     internal::FileCache* cache,
  46                     const base::FilePath& temporary_file_directory);
  47   ~TruncateOperation();
  48
  49   // Performs the truncate operation on the file at drive path |file_path| to
  50   // |length| bytes. Invokes |callback| when finished with the result of the
  51   // operation. |callback| must not be null.
  52   void Truncate(const base::FilePath& file_path,
  53                 int64 length,
  54                 const FileOperationCallback& callback);
  55  private:
  56   // Part of Truncate(). Called after EnsureFileDownloadedByPath() is complete.
  57   void TruncateAfterEnsureFileDownloadedByPath(
  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& local_id,
  67       const FileOperationCallback& callback,
  68       FileError error);
  69
  70   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
  71   OperationDelegate* delegate_;
  72   internal::ResourceMetadata* metadata_;
  73   internal::FileCache* cache_;
  74
  75   scoped_ptr<DownloadOperation> download_operation_;
  76
  77   base::ThreadChecker thread_checker_;
  78
  79   // Note: This should remain the last member so it'll be destroyed and
  80   // invalidate the weak pointers before any other members are destroyed.
  81   base::WeakPtrFactory<TruncateOperation> weak_ptr_factory_;
  82   DISALLOW_COPY_AND_ASSIGN(TruncateOperation);
  83 };
  84
  85 }  // namespace file_system
  86 }  // namespace drive
  87
  88 #endif  // COMPONENTS_DRIVE_FILE_SYSTEM_TRUNCATE_OPERATION_H_