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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 SYNC_SYNCABLE_DIRECTORY_H_
6 #define SYNC_SYNCABLE_DIRECTORY_H_
7 
8 #include <deque>
9 #include <set>
10 #include <string>
11 #include <vector>
12 
13 #include "base/basictypes.h"
14 #include "base/containers/hash_tables.h"
15 #include "base/file_util.h"
16 #include "base/gtest_prod_util.h"
17 #include "base/values.h"
18 #include "sync/base/sync_export.h"
19 #include "sync/internal_api/public/util/report_unrecoverable_error_function.h"
20 #include "sync/internal_api/public/util/weak_handle.h"
21 #include "sync/syncable/dir_open_result.h"
22 #include "sync/syncable/entry.h"
23 #include "sync/syncable/entry_kernel.h"
24 #include "sync/syncable/metahandle_set.h"
25 #include "sync/syncable/parent_child_index.h"
26 #include "sync/syncable/syncable_delete_journal.h"
27 
28 namespace syncer {
29 
30 class Cryptographer;
31 class TestUserShare;
32 class UnrecoverableErrorHandler;
33 
34 namespace syncable {
35 
36 class BaseTransaction;
37 class BaseWriteTransaction;
38 class DirectoryChangeDelegate;
39 class DirectoryBackingStore;
40 class NigoriHandler;
41 class ScopedKernelLock;
42 class TransactionObserver;
43 class WriteTransaction;
44 
45 enum InvariantCheckLevel {
46   OFF = 0,            // No checking.
47   VERIFY_CHANGES = 1, // Checks only mutated entries.  Does not check hierarchy.
48   FULL_DB_VERIFICATION = 2 // Check every entry.  This can be expensive.
49 };
50 
51 // Directory stores and manages EntryKernels.
52 //
53 // This class is tightly coupled to several other classes (see friends).
54 class SYNC_EXPORT Directory {
55   friend class BaseTransaction;
56   friend class Entry;
57   friend class ModelNeutralMutableEntry;
58   friend class MutableEntry;
59   friend class ReadTransaction;
60   friend class ScopedKernelLock;
61   friend class WriteTransaction;
62   friend class SyncableDirectoryTest;
63   friend class syncer::TestUserShare;
64   FRIEND_TEST_ALL_PREFIXES(SyncableDirectoryTest, ManageDeleteJournals);
65   FRIEND_TEST_ALL_PREFIXES(SyncableDirectoryTest,
66                            TakeSnapshotGetsAllDirtyHandlesTest);
67   FRIEND_TEST_ALL_PREFIXES(SyncableDirectoryTest,
68                            TakeSnapshotGetsOnlyDirtyHandlesTest);
69   FRIEND_TEST_ALL_PREFIXES(SyncableDirectoryTest,
70                            TakeSnapshotGetsMetahandlesToPurge);
71 
72  public:
73   typedef std::vector<int64> Metahandles;
74 
75   // Be careful when using these hash_map containers.  According to the spec,
76   // inserting into them may invalidate all iterators.
77   //
78   // It gets worse, though.  The Anroid STL library has a bug that means it may
79   // invalidate all iterators when you erase from the map, too.  That means that
80   // you can't iterate while erasing.  STLDeleteElements(), std::remove_if(),
81   // and other similar functions are off-limits too, until this bug is fixed.
82   //
83   // See http://sourceforge.net/p/stlport/bugs/239/.
84   typedef base::hash_map<int64, EntryKernel*> MetahandlesMap;
85   typedef base::hash_map<std::string, EntryKernel*> IdsMap;
86   typedef base::hash_map<std::string, EntryKernel*> TagsMap;
87   typedef std::string AttachmentIdUniqueId;
88   typedef base::hash_map<AttachmentIdUniqueId, MetahandleSet>
89       IndexByAttachmentId;
90 
91   static const base::FilePath::CharType kSyncDatabaseFilename[];
92 
93   // The dirty/clean state of kernel fields backed by the share_info table.
94   // This is public so it can be used in SaveChangesSnapshot for persistence.
95   enum KernelShareInfoStatus {
96     KERNEL_SHARE_INFO_INVALID,
97     KERNEL_SHARE_INFO_VALID,
98     KERNEL_SHARE_INFO_DIRTY
99   };
100 
101   // Various data that the Directory::Kernel we are backing (persisting data
102   // for) needs saved across runs of the application.
103   struct SYNC_EXPORT_PRIVATE PersistedKernelInfo {
104     PersistedKernelInfo();
105     ~PersistedKernelInfo();
106 
107     // Set the |download_progress| entry for the given model to a
108     // "first sync" start point.  When such a value is sent to the server,
109     // a full download of all objects of the model will be initiated.
110     void ResetDownloadProgress(ModelType model_type);
111 
112     // Last sync timestamp fetched from the server.
113     sync_pb::DataTypeProgressMarker download_progress[MODEL_TYPE_COUNT];
114     // Sync-side transaction version per data type. Monotonically incremented
115     // when updating native model. A copy is also saved in native model.
116     // Later out-of-sync models can be detected and fixed by comparing
117     // transaction versions of sync model and native model.
118     // TODO(hatiaol): implement detection and fixing of out-of-sync models.
119     //                Bug 154858.
120     int64 transaction_version[MODEL_TYPE_COUNT];
121     // The store birthday we were given by the server. Contents are opaque to
122     // the client.
123     std::string store_birthday;
124     // The next local ID that has not been used with this cache-GUID.
125     int64 next_id;
126     // The serialized bag of chips we were given by the server. Contents are
127     // opaque to the client. This is the serialization of a message of type
128     // ChipBag defined in sync.proto. It can contains NULL characters.
129     std::string bag_of_chips;
130     // The per-datatype context.
131     sync_pb::DataTypeContext datatype_context[MODEL_TYPE_COUNT];
132   };
133 
134   // What the Directory needs on initialization to create itself and its Kernel.
135   // Filled by DirectoryBackingStore::Load.
136   struct KernelLoadInfo {
137     PersistedKernelInfo kernel_info;
138     std::string cache_guid;  // Created on first initialization, never changes.
139     int64 max_metahandle;    // Computed (using sql MAX aggregate) on init.
KernelLoadInfoKernelLoadInfo140     KernelLoadInfo() : max_metahandle(0) {
141     }
142   };
143 
144   // When the Directory is told to SaveChanges, a SaveChangesSnapshot is
145   // constructed and forms a consistent snapshot of what needs to be sent to
146   // the backing store.
147   struct SYNC_EXPORT_PRIVATE SaveChangesSnapshot {
148     SaveChangesSnapshot();
149     ~SaveChangesSnapshot();
150 
151     KernelShareInfoStatus kernel_info_status;
152     PersistedKernelInfo kernel_info;
153     EntryKernelSet dirty_metas;
154     MetahandleSet metahandles_to_purge;
155     EntryKernelSet delete_journals;
156     MetahandleSet delete_journals_to_purge;
157   };
158 
159   // Does not take ownership of |encryptor|.
160   // |report_unrecoverable_error_function| may be NULL.
161   // Takes ownership of |store|.
162   Directory(
163       DirectoryBackingStore* store,
164       UnrecoverableErrorHandler* unrecoverable_error_handler,
165       ReportUnrecoverableErrorFunction
166           report_unrecoverable_error_function,
167       NigoriHandler* nigori_handler,
168       Cryptographer* cryptographer);
169   virtual ~Directory();
170 
171   // Does not take ownership of |delegate|, which must not be NULL.
172   // Starts sending events to |delegate| if the returned result is
173   // OPENED.  Note that events to |delegate| may be sent from *any*
174   // thread.  |transaction_observer| must be initialized.
175   DirOpenResult Open(const std::string& name,
176                      DirectoryChangeDelegate* delegate,
177                      const WeakHandle<TransactionObserver>&
178                          transaction_observer);
179 
180   // Stops sending events to the delegate and the transaction
181   // observer.
182   void Close();
183 
184   int64 NextMetahandle();
185   // Returns a negative integer unique to this client.
186   syncable::Id NextId();
187 
good()188   bool good() const { return NULL != kernel_; }
189 
190   // The download progress is an opaque token provided by the sync server
191   // to indicate the continuation state of the next GetUpdates operation.
192   void GetDownloadProgress(
193       ModelType type,
194       sync_pb::DataTypeProgressMarker* value_out) const;
195   void GetDownloadProgressAsString(
196       ModelType type,
197       std::string* value_out) const;
198   size_t GetEntriesCount() const;
199   void SetDownloadProgress(
200       ModelType type,
201       const sync_pb::DataTypeProgressMarker& value);
202 
203   // Gets/Increments transaction version of a model type. Must be called when
204   // holding kernel mutex.
205   int64 GetTransactionVersion(ModelType type) const;
206   void IncrementTransactionVersion(ModelType type);
207 
208   // Getter/setters for the per datatype context.
209   void GetDataTypeContext(BaseTransaction* trans,
210                           ModelType type,
211                           sync_pb::DataTypeContext* context) const;
212   void SetDataTypeContext(BaseWriteTransaction* trans,
213                           ModelType type,
214                           const sync_pb::DataTypeContext& context);
215 
216   ModelTypeSet InitialSyncEndedTypes();
217   bool InitialSyncEndedForType(ModelType type);
218   bool InitialSyncEndedForType(BaseTransaction* trans, ModelType type);
219 
name()220   const std::string& name() const { return kernel_->name; }
221 
222   // (Account) Store birthday is opaque to the client, so we keep it in the
223   // format it is in the proto buffer in case we switch to a binary birthday
224   // later.
225   std::string store_birthday() const;
226   void set_store_birthday(const std::string& store_birthday);
227 
228   // (Account) Bag of chip is an opaque state used by the server to track the
229   // client.
230   std::string bag_of_chips() const;
231   void set_bag_of_chips(const std::string& bag_of_chips);
232 
233   // Unique to each account / client pair.
234   std::string cache_guid() const;
235 
236   // Returns a pointer to our Nigori node handler.
237   NigoriHandler* GetNigoriHandler();
238 
239   // Returns a pointer to our cryptographer. Does not transfer ownership.
240   // Not thread safe, so should only be accessed while holding a transaction.
241   Cryptographer* GetCryptographer(const BaseTransaction* trans);
242 
243   // Returns true if the directory had encountered an unrecoverable error.
244   // Note: Any function in |Directory| that can be called without holding a
245   // transaction need to check if the Directory already has an unrecoverable
246   // error on it.
247   bool unrecoverable_error_set(const BaseTransaction* trans) const;
248 
249   // Called to immediately report an unrecoverable error (but don't
250   // propagate it up).
ReportUnrecoverableError()251   void ReportUnrecoverableError() {
252     if (report_unrecoverable_error_function_) {
253       report_unrecoverable_error_function_();
254     }
255   }
256 
257   // Called to set the unrecoverable error on the directory and to propagate
258   // the error to upper layers.
259   void OnUnrecoverableError(const BaseTransaction* trans,
260                             const tracked_objects::Location& location,
261                             const std::string & message);
262 
263   DeleteJournal* delete_journal();
264 
265   // Returns the child meta handles (even those for deleted/unlinked
266   // nodes) for given parent id.  Clears |result| if there are no
267   // children.
268   bool GetChildHandlesById(BaseTransaction*, const Id& parent_id,
269       Metahandles* result);
270 
271   // Counts all items under the given node, including the node itself.
272   int GetTotalNodeCount(BaseTransaction*, EntryKernel* kernel_) const;
273 
274   // Returns this item's position within its parent folder.
275   // The left-most item is 0, second left-most is 1, etc.
276   int GetPositionIndex(BaseTransaction*, EntryKernel* kernel_) const;
277 
278   // Returns true iff |id| has children.
279   bool HasChildren(BaseTransaction* trans, const Id& id);
280 
281   // Find the first child in the positional ordering under a parent,
282   // and fill in |*first_child_id| with its id.  Fills in a root Id if
283   // parent has no children.  Returns true if the first child was
284   // successfully found, or false if an error was encountered.
285   Id GetFirstChildId(BaseTransaction* trans, const EntryKernel* parent);
286 
287   // These functions allow one to fetch the next or previous item under
288   // the same folder.  Returns the "root" ID if there is no predecessor
289   // or successor.
290   //
291   // TODO(rlarocque): These functions are used mainly for tree traversal.  We
292   // should replace these with an iterator API.  See crbug.com/178275.
293   syncable::Id GetPredecessorId(EntryKernel*);
294   syncable::Id GetSuccessorId(EntryKernel*);
295 
296   // Places |e| as a successor to |predecessor|.  If |predecessor| is NULL,
297   // |e| will be placed as the left-most item in its folder.
298   //
299   // Both |e| and |predecessor| must be valid entries under the same parent.
300   //
301   // TODO(rlarocque): This function includes limited support for placing items
302   // with valid positions (ie. Bookmarks) as siblings of items that have no set
303   // ordering (ie. Autofill items).  This support is required only for tests,
304   // and should be removed.  See crbug.com/178282.
305   void PutPredecessor(EntryKernel* e, EntryKernel* predecessor);
306 
307   // SaveChanges works by taking a consistent snapshot of the current Directory
308   // state and indices (by deep copy) under a ReadTransaction, passing this
309   // snapshot to the backing store under no transaction, and finally cleaning
310   // up by either purging entries no longer needed (this part done under a
311   // WriteTransaction) or rolling back the dirty bits.  It also uses
312   // internal locking to enforce SaveChanges operations are mutually exclusive.
313   //
314   // WARNING: THIS METHOD PERFORMS SYNCHRONOUS I/O VIA SQLITE.
315   bool SaveChanges();
316 
317   // Returns the number of entities with the unsynced bit set.
318   int64 unsynced_entity_count() const;
319 
320   // Get GetUnsyncedMetaHandles should only be called after SaveChanges and
321   // before any new entries have been created. The intention is that the
322   // syncer should call it from its PerformSyncQueries member.
323   void GetUnsyncedMetaHandles(BaseTransaction* trans,
324                               Metahandles* result);
325 
326   // Returns whether or not this |type| has unapplied updates.
327   bool TypeHasUnappliedUpdates(ModelType type);
328 
329   // Get all the metahandles for unapplied updates for a given set of
330   // server types.
331   void GetUnappliedUpdateMetaHandles(BaseTransaction* trans,
332                                      FullModelTypeSet server_types,
333                                      std::vector<int64>* result);
334 
335   // Get all the metahandles of entries of |type|.
336   void GetMetaHandlesOfType(BaseTransaction* trans,
337                             ModelType type,
338                             Metahandles* result);
339 
340   // Get metahandle counts for various criteria to show on the
341   // about:sync page. The information is computed on the fly
342   // each time. If this results in a significant performance hit,
343   // additional data structures can be added to cache results.
344   void CollectMetaHandleCounts(std::vector<int>* num_entries_by_type,
345                                std::vector<int>* num_to_delete_entries_by_type);
346 
347   // Returns a ListValue serialization of all nodes for the given type.
348   scoped_ptr<base::ListValue> GetNodeDetailsForType(
349       BaseTransaction* trans,
350       ModelType type);
351 
352   // Sets the level of invariant checking performed after transactions.
353   void SetInvariantCheckLevel(InvariantCheckLevel check_level);
354 
355   // Checks tree metadata consistency following a transaction.  It is intended
356   // to provide a reasonable tradeoff between performance and comprehensiveness
357   // and may be used in release code.
358   bool CheckInvariantsOnTransactionClose(
359       syncable::BaseTransaction* trans,
360       const MetahandleSet& modified_handles);
361 
362   // Forces a full check of the directory.  This operation may be slow and
363   // should not be invoked outside of tests.
364   bool FullyCheckTreeInvariants(BaseTransaction *trans);
365 
366   // Purges data associated with any entries whose ModelType or ServerModelType
367   // is found in |disabled_types|, from sync directory _both_ in memory and on
368   // disk. Only valid, "real" model types are allowed in |disabled_types| (see
369   // model_type.h for definitions).
370   // 1. Data associated with |types_to_journal| is saved in the delete journal
371   // to help prevent back-from-dead problem due to offline delete in the next
372   // sync session. |types_to_journal| must be a subset of |disabled_types|.
373   // 2. Data associated with |types_to_unapply| is reset to an "unapplied"
374   // state, wherein all local data is deleted and IS_UNAPPLIED is set to true.
375   // This is useful when there's no benefit in discarding the currently
376   // downloaded state, such as when there are cryptographer errors.
377   // |types_to_unapply| must be a subset of |disabled_types|.
378   // 3. All other data is purged entirely.
379   // Note: "Purge" is just meant to distinguish from "deleting" entries, which
380   // means something different in the syncable namespace.
381   // WARNING! This can be real slow, as it iterates over all entries.
382   // WARNING! Performs synchronous I/O.
383   // Returns: true on success, false if an error was encountered.
384   virtual bool PurgeEntriesWithTypeIn(ModelTypeSet disabled_types,
385                                       ModelTypeSet types_to_journal,
386                                       ModelTypeSet types_to_unapply);
387 
388   // Resets the base_versions and server_versions of all synced entities
389   // associated with |type| to 1.
390   // WARNING! This can be slow, as it iterates over all entries for a type.
391   bool ResetVersionsForType(BaseWriteTransaction* trans, ModelType type);
392 
393   // Returns true iff the attachment identified by |attachment_id_proto| is
394   // linked to an entry.
395   //
396   // An attachment linked to a deleted entry is still considered linked if the
397   // entry hasn't yet been purged.
398   bool IsAttachmentLinked(
399       const sync_pb::AttachmentIdProto& attachment_id_proto) const;
400 
401   // Given attachment id return metahandles to all entries that reference this
402   // attachment.
403   void GetMetahandlesByAttachmentId(
404       BaseTransaction* trans,
405       const sync_pb::AttachmentIdProto& attachment_id_proto,
406       Metahandles* result);
407 
408   // Change entry to not dirty. Used in special case when we don't want to
409   // persist modified entry on disk. e.g. SyncBackupManager uses this to
410   // preserve sync preferences in DB on disk.
411   void UnmarkDirtyEntry(WriteTransaction* trans, Entry* entry);
412 
413  protected:  // for friends, mainly used by Entry constructors
414   virtual EntryKernel* GetEntryByHandle(int64 handle);
415   virtual EntryKernel* GetEntryByHandle(int64 metahandle,
416       ScopedKernelLock* lock);
417   virtual EntryKernel* GetEntryById(const Id& id);
418   EntryKernel* GetEntryByServerTag(const std::string& tag);
419   virtual EntryKernel* GetEntryByClientTag(const std::string& tag);
420   bool ReindexId(BaseWriteTransaction* trans, EntryKernel* const entry,
421                  const Id& new_id);
422   bool ReindexParentId(BaseWriteTransaction* trans, EntryKernel* const entry,
423                        const Id& new_parent_id);
424   // Update the attachment index for |metahandle| removing it from the index
425   // under |old_metadata| entries and add it under |new_metadata| entries.
426   void UpdateAttachmentIndex(const int64 metahandle,
427                              const sync_pb::AttachmentMetadata& old_metadata,
428                              const sync_pb::AttachmentMetadata& new_metadata);
429   void ClearDirtyMetahandles();
430 
431   DirOpenResult OpenImpl(
432       const std::string& name,
433       DirectoryChangeDelegate* delegate,
434       const WeakHandle<TransactionObserver>& transaction_observer);
435 
436  private:
437   struct Kernel {
438     // |delegate| must not be NULL.  |transaction_observer| must be
439     // initialized.
440     Kernel(const std::string& name, const KernelLoadInfo& info,
441            DirectoryChangeDelegate* delegate,
442            const WeakHandle<TransactionObserver>& transaction_observer);
443 
444     ~Kernel();
445 
446     // Implements ReadTransaction / WriteTransaction using a simple lock.
447     base::Lock transaction_mutex;
448 
449     // Protected by transaction_mutex.  Used by WriteTransactions.
450     int64 next_write_transaction_id;
451 
452     // The name of this directory.
453     std::string const name;
454 
455     // Protects all members below.
456     // The mutex effectively protects all the indices, but not the
457     // entries themselves.  So once a pointer to an entry is pulled
458     // from the index, the mutex can be unlocked and entry read or written.
459     //
460     // Never hold the mutex and do anything with the database or any
461     // other buffered IO.  Violating this rule will result in deadlock.
462     base::Lock mutex;
463 
464     // Entries indexed by metahandle.  This container is considered to be the
465     // owner of all EntryKernels, which may be referened by the other
466     // containers.  If you remove an EntryKernel from this map, you probably
467     // want to remove it from all other containers and delete it, too.
468     MetahandlesMap metahandles_map;
469 
470     // Entries indexed by id
471     IdsMap ids_map;
472 
473     // Entries indexed by server tag.
474     // This map does not include any entries with non-existent server tags.
475     TagsMap server_tags_map;
476 
477     // Entries indexed by client tag.
478     // This map does not include any entries with non-existent client tags.
479     // IS_DEL items are included.
480     TagsMap client_tags_map;
481 
482     // Contains non-deleted items, indexed according to parent and position
483     // within parent.  Protected by the ScopedKernelLock.
484     ParentChildIndex parent_child_index;
485 
486     // This index keeps track of which metahandles refer to a given attachment.
487     // Think of it as the inverse of EntryKernel's AttachmentMetadata Records.
488     //
489     // Because entries can be undeleted (e.g. PutIsDel(false)), entries should
490     // not removed from the index until they are actually deleted from memory.
491     //
492     // All access should go through IsAttachmentLinked,
493     // RemoveFromAttachmentIndex, AddToAttachmentIndex, and
494     // UpdateAttachmentIndex methods to avoid iterator invalidation errors.
495     IndexByAttachmentId index_by_attachment_id;
496 
497     // 3 in-memory indices on bits used extremely frequently by the syncer.
498     // |unapplied_update_metahandles| is keyed by the server model type.
499     MetahandleSet unapplied_update_metahandles[MODEL_TYPE_COUNT];
500     MetahandleSet unsynced_metahandles;
501     // Contains metahandles that are most likely dirty (though not
502     // necessarily).  Dirtyness is confirmed in TakeSnapshotForSaveChanges().
503     MetahandleSet dirty_metahandles;
504 
505     // When a purge takes place, we remove items from all our indices and stash
506     // them in here so that SaveChanges can persist their permanent deletion.
507     MetahandleSet metahandles_to_purge;
508 
509     KernelShareInfoStatus info_status;
510 
511     // These 3 members are backed in the share_info table, and
512     // their state is marked by the flag above.
513 
514     // A structure containing the Directory state that is written back into the
515     // database on SaveChanges.
516     PersistedKernelInfo persisted_info;
517 
518     // A unique identifier for this account's cache db, used to generate
519     // unique server IDs. No need to lock, only written at init time.
520     const std::string cache_guid;
521 
522     // It doesn't make sense for two threads to run SaveChanges at the same
523     // time; this mutex protects that activity.
524     base::Lock save_changes_mutex;
525 
526     // The next metahandle is protected by kernel mutex.
527     int64 next_metahandle;
528 
529     // The delegate for directory change events.  Must not be NULL.
530     DirectoryChangeDelegate* const delegate;
531 
532     // The transaction observer.
533     const WeakHandle<TransactionObserver> transaction_observer;
534   };
535 
536   // These private versions expect the kernel lock to already be held
537   // before calling.
538   EntryKernel* GetEntryById(const Id& id, ScopedKernelLock* const lock);
539 
540   // A helper that implements the logic of checking tree invariants.
541   bool CheckTreeInvariants(syncable::BaseTransaction* trans,
542                            const MetahandleSet& handles);
543 
544   // Helper to prime metahandles_map, ids_map, parent_child_index,
545   // unsynced_metahandles, unapplied_update_metahandles, server_tags_map and
546   // client_tags_map from metahandles_index.  The input |handles_map| will be
547   // cleared during the initialization process.
548   void InitializeIndices(MetahandlesMap* handles_map);
549 
550   // Constructs a consistent snapshot of the current Directory state and
551   // indices (by deep copy) under a ReadTransaction for use in |snapshot|.
552   // See SaveChanges() for more information.
553   void TakeSnapshotForSaveChanges(SaveChangesSnapshot* snapshot);
554 
555   // Purges from memory any unused, safe to remove entries that were
556   // successfully deleted on disk as a result of the SaveChanges that processed
557   // |snapshot|.  See SaveChanges() for more information.
558   bool VacuumAfterSaveChanges(const SaveChangesSnapshot& snapshot);
559 
560   // Rolls back dirty bits in the event that the SaveChanges that
561   // processed |snapshot| failed, for example, due to no disk space.
562   void HandleSaveChangesFailure(const SaveChangesSnapshot& snapshot);
563 
564   // For new entry creation only
565   bool InsertEntry(BaseWriteTransaction* trans,
566                    EntryKernel* entry, ScopedKernelLock* lock);
567   bool InsertEntry(BaseWriteTransaction* trans, EntryKernel* entry);
568 
569   // Used by CheckTreeInvariants
570   void GetAllMetaHandles(BaseTransaction* trans, MetahandleSet* result);
571   bool SafeToPurgeFromMemory(WriteTransaction* trans,
572                              const EntryKernel* const entry) const;
573 
574   // A helper used by GetTotalNodeCount.
575   void GetChildSetForKernel(
576       BaseTransaction*,
577       EntryKernel* kernel_,
578       std::deque<const OrderedChildSet*>* child_sets) const;
579 
580   // Append the handles of the children of |parent_id| to |result|.
581   void AppendChildHandles(
582       const ScopedKernelLock& lock,
583       const Id& parent_id, Directory::Metahandles* result);
584 
585   // Helper methods used by PurgeDisabledTypes.
586   void UnapplyEntry(EntryKernel* entry);
587   void DeleteEntry(bool save_to_journal,
588                    EntryKernel* entry,
589                    EntryKernelSet* entries_to_journal,
590                    const ScopedKernelLock& lock);
591 
592   // Remove each of |metahandle|'s attachment ids from index_by_attachment_id.
593   void RemoveFromAttachmentIndex(
594       const int64 metahandle,
595       const sync_pb::AttachmentMetadata& attachment_metadata,
596       const ScopedKernelLock& lock);
597   // Add each of |metahandle|'s attachment ids to the index_by_attachment_id.
598   void AddToAttachmentIndex(
599       const int64 metahandle,
600       const sync_pb::AttachmentMetadata& attachment_metadata,
601       const ScopedKernelLock& lock);
602 
603   Kernel* kernel_;
604 
605   scoped_ptr<DirectoryBackingStore> store_;
606 
607   UnrecoverableErrorHandler* const unrecoverable_error_handler_;
608   const ReportUnrecoverableErrorFunction report_unrecoverable_error_function_;
609   bool unrecoverable_error_set_;
610 
611   // Not owned.
612   NigoriHandler* const nigori_handler_;
613   Cryptographer* const cryptographer_;
614 
615   InvariantCheckLevel invariant_check_level_;
616 
617   // Maintain deleted entries not in |kernel_| until it's verified that they
618   // are deleted in native models as well.
619   scoped_ptr<DeleteJournal> delete_journal_;
620 
621   DISALLOW_COPY_AND_ASSIGN(Directory);
622 };
623 
624 }  // namespace syncable
625 }  // namespace syncer
626 
627 #endif // SYNC_SYNCABLE_DIRECTORY_H_
628