chrome/browser/sync_file_system/remote_change_processor.h

   1 // Copyright (c) 2012 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_SYNC_FILE_SYSTEM_REMOTE_CHANGE_PROCESSOR_H_
   6 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_CHANGE_PROCESSOR_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/callback_forward.h"
  10 #include "webkit/fileapi/syncable/sync_callbacks.h"
  11 #include "webkit/fileapi/syncable/sync_status_code.h"
  12
  13 namespace base {
  14 class FilePath;
  15 }
  16
  17 namespace fileapi {
  18 class FileSystemURL;
  19 }
  20
  21 namespace sync_file_system {
  22
  23 class FileChange;
  24 class FileChangeList;
  25 class SyncFileMetadata;
  26
  27 // Represents an interface to process one remote change and applies
  28 // it to the local file system.
  29 // This interface is to be implemented/backed by LocalSyncFileService.
  30 class RemoteChangeProcessor {
  31  public:
  32   // Callback type for PrepareForProcessRemoteChange.
  33   // |file_type| indicates the current file/directory type of the target
  34   // URL in the local filesystem. If the target URL does not exist it is
  35   // set to SYNC_FILE_TYPE_UNKNOWN.
  36   // |changes| indicates a set of pending changes for the target URL.
  37   typedef base::Callback<void(
  38       SyncStatusCode status,
  39       const SyncFileMetadata& metadata,
  40       const FileChangeList& changes)> PrepareChangeCallback;
  41
  42   RemoteChangeProcessor() {}
  43   virtual ~RemoteChangeProcessor() {}
  44
  45   // This must be called before processing the change for the |url|
  46   // for sync service |service_name|.
  47   // This tries to lock the target |url| and returns the local changes
  48   // if any. (The change returned by the callback is to make a decision
  49   // on conflict resolution, but NOT for applying local changes to the remote,
  50   // which is supposed to be done by LocalChangeProcessor)
  51   virtual void PrepareForProcessRemoteChange(
  52       const fileapi::FileSystemURL& url,
  53       const std::string& service_name,
  54       const PrepareChangeCallback& callback) = 0;
  55
  56   // This is called to apply the remote |change|. If the change type is
  57   // ADD_OR_UPDATE for a file, |local_path| needs to point to a
  58   // local file path that contains the latest file image (e.g. a path
  59   // to a temporary file which has the data downloaded from the server).
  60   // This may fail with an error but should NOT result in a conflict
  61   // (as we must have checked the change status in PrepareRemoteSync and
  62   // have disabled any further writing).
  63   virtual void ApplyRemoteChange(
  64       const FileChange& change,
  65       const base::FilePath& local_path,
  66       const fileapi::FileSystemURL& url,
  67       const SyncStatusCallback& callback) = 0;
  68
  69   // Clears all local changes. This should be called when the remote sync
  70   // service reconciled or processed the existing local changes while
  71   // processing a remote change.
  72   virtual void ClearLocalChanges(
  73       const fileapi::FileSystemURL& url,
  74       const base::Closure& completion_callback) = 0;
  75
  76   // Records a fake local change so that the change will be processed in the
  77   // next local sync.
  78   // This is called when the remote side wants to trigger a local sync
  79   // to propagate the local change to the remote change (e.g. to
  80   // resolve a conflict by uploading the local file).
  81   virtual void RecordFakeLocalChange(
  82       const fileapi::FileSystemURL& url,
  83       const FileChange& change,
  84       const SyncStatusCallback& callback) = 0;
  85
  86  private:
  87   DISALLOW_COPY_AND_ASSIGN(RemoteChangeProcessor);
  88 };
  89
  90 }  // namespace sync_file_system
  91
  92 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_CHANGE_PROCESSOR_H_