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      1 // Copyright 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 SYNC_API_SYNC_DATA_H_
      6 #define SYNC_API_SYNC_DATA_H_
      7 
      8 #include <iosfwd>
      9 #include <string>
     10 #include <vector>
     11 
     12 #include "base/basictypes.h"
     13 #include "base/callback.h"
     14 #include "base/memory/ref_counted.h"
     15 #include "base/stl_util.h"
     16 #include "base/time/time.h"
     17 #include "sync/api/attachments/attachment_id.h"
     18 #include "sync/base/sync_export.h"
     19 #include "sync/internal_api/public/attachments/attachment_service_proxy.h"
     20 #include "sync/internal_api/public/base/model_type.h"
     21 #include "sync/internal_api/public/util/immutable.h"
     22 #include "sync/internal_api/public/util/weak_handle.h"
     23 
     24 namespace sync_pb {
     25 class EntitySpecifics;
     26 class SyncEntity;
     27 }  // namespace sync_pb
     28 
     29 namespace syncer {
     30 
     31 class AttachmentService;
     32 class SyncDataLocal;
     33 class SyncDataRemote;
     34 
     35 // A light-weight container for immutable sync data. Pass-by-value and storage
     36 // in STL containers are supported and encouraged if helpful.
     37 class SYNC_EXPORT SyncData {
     38  public:
     39   // Creates an empty and invalid SyncData.
     40   SyncData();
     41   ~SyncData();
     42 
     43   // Default copy and assign welcome.
     44 
     45   // Helper methods for creating SyncData objects for local data.
     46   //
     47   // |sync_tag| Must be a string unique to this datatype and is used as a node
     48   // identifier server-side.
     49   //
     50   // For deletes: |datatype| must specify the datatype who node is being
     51   // deleted.
     52   //
     53   // For adds/updates: |specifics| must be valid and |non_unique_title| (can be
     54   // the same as |sync_tag|) must be specfied.  Note: |non_unique_title| is
     55   // primarily for debug purposes, and will be overwritten if the datatype is
     56   // encrypted.
     57   //
     58   // For data with attachments: |attachment_ids| must not contain duplicates.
     59   static SyncData CreateLocalDelete(
     60       const std::string& sync_tag,
     61       ModelType datatype);
     62   static SyncData CreateLocalData(
     63       const std::string& sync_tag,
     64       const std::string& non_unique_title,
     65       const sync_pb::EntitySpecifics& specifics);
     66   static SyncData CreateLocalDataWithAttachments(
     67       const std::string& sync_tag,
     68       const std::string& non_unique_title,
     69       const sync_pb::EntitySpecifics& specifics,
     70       const AttachmentIdList& attachment_ids);
     71 
     72   // Helper method for creating SyncData objects originating from the syncer.
     73   static SyncData CreateRemoteData(
     74       int64 id,
     75       const sync_pb::EntitySpecifics& specifics,
     76       const base::Time& last_modified_time,
     77       const AttachmentIdList& attachment_ids,
     78       const syncer::AttachmentServiceProxy& attachment_service);
     79 
     80   // Whether this SyncData holds valid data. The only way to have a SyncData
     81   // without valid data is to use the default constructor.
     82   bool IsValid() const;
     83 
     84   // Return the datatype we're holding information about. Derived from the sync
     85   // datatype specifics.
     86   ModelType GetDataType() const;
     87 
     88   // Return the current sync datatype specifics.
     89   const sync_pb::EntitySpecifics& GetSpecifics() const;
     90 
     91   // Return the non unique title (for debugging). Currently only set for data
     92   // going TO the syncer, not from.
     93   const std::string& GetTitle() const;
     94 
     95   // Whether this sync data is for local data or data coming from the syncer.
     96   bool IsLocal() const;
     97 
     98   std::string ToString() const;
     99 
    100   // Return a list of this SyncData's attachment ids.
    101   //
    102   // The attachments may or may not be present on this device.
    103   AttachmentIdList GetAttachmentIds() const;
    104 
    105   // TODO(zea): Query methods for other sync properties: parent, successor, etc.
    106 
    107  protected:
    108   // These data members are protected so derived types like SyncDataLocal and
    109   // SyncDataRemote can access them.
    110 
    111   // Necessary since we forward-declare sync_pb::SyncEntity; see
    112   // comments in immutable.h.
    113   struct SYNC_EXPORT ImmutableSyncEntityTraits {
    114     typedef sync_pb::SyncEntity* Wrapper;
    115 
    116     static void InitializeWrapper(Wrapper* wrapper);
    117 
    118     static void DestroyWrapper(Wrapper* wrapper);
    119 
    120     static const sync_pb::SyncEntity& Unwrap(const Wrapper& wrapper);
    121 
    122     static sync_pb::SyncEntity* UnwrapMutable(Wrapper* wrapper);
    123 
    124     static void Swap(sync_pb::SyncEntity* t1, sync_pb::SyncEntity* t2);
    125   };
    126 
    127   typedef Immutable<sync_pb::SyncEntity, ImmutableSyncEntityTraits>
    128       ImmutableSyncEntity;
    129 
    130   // Equal to kInvalidId iff this is local.
    131   int64 id_;
    132 
    133   // This may be null if the SyncData represents a deleted item.
    134   base::Time remote_modification_time_;
    135 
    136   // The actual shared sync entity being held.
    137   ImmutableSyncEntity immutable_entity_;
    138 
    139   AttachmentServiceProxy attachment_service_;
    140 
    141  private:
    142   // Whether this SyncData holds valid data.
    143   bool is_valid_;
    144 
    145   // Clears |entity| and |attachments|.
    146   SyncData(int64 id,
    147            sync_pb::SyncEntity* entity,
    148            const base::Time& remote_modification_time,
    149            const syncer::AttachmentServiceProxy& attachment_service);
    150 };
    151 
    152 // A SyncData going to the syncer.
    153 class SYNC_EXPORT SyncDataLocal : public SyncData {
    154  public:
    155   // Construct a SyncDataLocal from a SyncData.
    156   //
    157   // |sync_data|'s IsLocal() must be true.
    158   explicit SyncDataLocal(const SyncData& sync_data);
    159   ~SyncDataLocal();
    160 
    161   // Return the value of the unique client tag. This is only set for data going
    162   // TO the syncer, not coming from.
    163   const std::string& GetTag() const;
    164 };
    165 
    166 // A SyncData that comes from the syncer.
    167 class SYNC_EXPORT SyncDataRemote : public SyncData {
    168  public:
    169   // Construct a SyncDataRemote from a SyncData.
    170   //
    171   // |sync_data|'s IsLocal() must be false.
    172   explicit SyncDataRemote(const SyncData& sync_data);
    173   ~SyncDataRemote();
    174 
    175   // Return the last motification time according to the server. This may be null
    176   // if the SyncData represents a deleted item.
    177   const base::Time& GetModifiedTime() const;
    178 
    179   int64 GetId() const;
    180 
    181   // Retrieve the attachments indentified by |attachment_ids|. Invoke
    182   // |callback| with the requested attachments.
    183   //
    184   // |callback| will be invoked when the operation is complete (successfully
    185   // or otherwise).
    186   //
    187   // Retrieving the requested attachments may require reading local storage or
    188   // requesting the attachments from the network.
    189   //
    190   void GetOrDownloadAttachments(
    191       const AttachmentIdList& attachment_ids,
    192       const AttachmentService::GetOrDownloadCallback& callback);
    193 
    194   // Drop (delete from local storage) the attachments associated with this
    195   // SyncData specified in |attachment_ids|. This method will not delete
    196   // attachments from the server.
    197   //
    198   // |callback| will be invoked when the operation is complete (successfully
    199   // or otherwise).
    200   void DropAttachments(const AttachmentIdList& attachment_ids,
    201                        const AttachmentService::DropCallback& callback);
    202 };
    203 
    204 // gmock printer helper.
    205 void PrintTo(const SyncData& sync_data, std::ostream* os);
    206 
    207 typedef std::vector<SyncData> SyncDataList;
    208 
    209 }  // namespace syncer
    210 
    211 #endif  // SYNC_API_SYNC_DATA_H_
    212