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 "chrome/browser/sync_file_system/sync_callbacks.h"
  11 #include "chrome/browser/sync_file_system/sync_status_code.h"
  12
  13 namespace base {
  14 class FilePath;
  15 }
  16
  17 namespace storage {
  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   // This tries to lock the target |url| and returns the local changes
  47   // if any. (The change returned by the callback is to make a decision
  48   // on conflict resolution, but NOT for applying local changes to the remote,
  49   // which is supposed to be done by LocalChangeProcessor)
  50   virtual void PrepareForProcessRemoteChange(
  51       const storage::FileSystemURL& url,
  52       const PrepareChangeCallback& callback) = 0;
  53
  54   // This is called to apply the remote |change|. If the change type is
  55   // ADD_OR_UPDATE for a file, |local_path| needs to point to a
  56   // local file path that contains the latest file image (e.g. a path
  57   // to a temporary file which has the data downloaded from the server).
  58   // This may fail with an error but should NOT result in a conflict
  59   // (as we must have checked the change status in PrepareRemoteSync and
  60   // have disabled any further writing).
  61   virtual void ApplyRemoteChange(const FileChange& change,
  62                                  const base::FilePath& local_path,
  63                                  const storage::FileSystemURL& url,
  64                                  const SyncStatusCallback& callback) = 0;
  65
  66   // Finalizes the remote sync started by PrepareForProcessRemoteChange.
  67   // This clears sync flag on |url| to unlock the file for future writes/sync.
  68   // Clears all local changes if |clear_local_changes| is true.
  69   // This should be set to true when the remote sync service reconciled or
  70   // processed the existing local changes while processing a remote change.
  71   virtual void FinalizeRemoteSync(const storage::FileSystemURL& url,
  72                                   bool clear_local_changes,
  73                                   const base::Closure& completion_callback) = 0;
  74
  75   // Records a fake local change so that the change will be processed in the
  76   // next local sync.
  77   // This is called when the remote side wants to trigger a local sync
  78   // to propagate the local change to the remote change (e.g. to
  79   // resolve a conflict by uploading the local file).
  80   virtual void RecordFakeLocalChange(const storage::FileSystemURL& url,
  81                                      const FileChange& change,
  82                                      const SyncStatusCallback& callback) = 0;
  83
  84  private:
  85   DISALLOW_COPY_AND_ASSIGN(RemoteChangeProcessor);
  86 };
  87
  88 }  // namespace sync_file_system
  89
  90 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_CHANGE_PROCESSOR_H_