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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_SYNCABLE_SYNCABLE_BASE_TRANSACTION_H_
      6 #define SYNC_SYNCABLE_SYNCABLE_BASE_TRANSACTION_H_
      7 
      8 #include "base/location.h"
      9 #include "sync/base/sync_export.h"
     10 #include "sync/syncable/syncable_id.h"
     11 
     12 namespace syncer {
     13 namespace syncable {
     14 
     15 class Directory;
     16 
     17 // A WriteTransaction has a writer tag describing which body of code is doing
     18 // the write. This is defined up here since WriteTransactionInfo also contains
     19 // one.
     20 enum WriterTag {
     21   INVALID,
     22   SYNCER,
     23   AUTHWATCHER,
     24   UNITTEST,
     25   VACUUM_AFTER_SAVE,
     26   HANDLE_SAVE_FAILURE,
     27   PURGE_ENTRIES,
     28   SYNCAPI,
     29 };
     30 
     31 // Make sure to update this if you update WriterTag.
     32 std::string WriterTagToString(WriterTag writer_tag);
     33 
     34 class SYNC_EXPORT BaseTransaction {
     35  public:
     36   static Id root_id();
     37 
     38   Directory* directory() const;
     39 
     40   virtual ~BaseTransaction();
     41 
     42   // This should be called when a database corruption is detected and there is
     43   // no way for us to recover short of wiping the database clean. When this is
     44   // called we set a bool in the transaction. The caller has to unwind the
     45   // stack. When the destructor for the transaction is called it acts upon the
     46   // bool and calls the Directory to handle the unrecoverable error.
     47   void OnUnrecoverableError(const tracked_objects::Location& location,
     48                             const std::string& message);
     49 
     50   bool unrecoverable_error_set() const;
     51 
     52  protected:
     53   BaseTransaction(const tracked_objects::Location& from_here,
     54                   const char* name,
     55                   WriterTag writer,
     56                   Directory* directory);
     57 
     58   void Lock();
     59   void Unlock();
     60 
     61   // This should be called before unlocking because it calls the Direcotry's
     62   // OnUnrecoverableError method which is not protected by locks and could
     63   // be called from any thread. Holding the transaction lock ensures only one
     64   // thread could call the method at a time.
     65   void HandleUnrecoverableErrorIfSet();
     66 
     67   const tracked_objects::Location from_here_;
     68   const char* const name_;
     69   WriterTag writer_;
     70   Directory* const directory_;
     71 
     72   // Error information.
     73   bool unrecoverable_error_set_;
     74   tracked_objects::Location unrecoverable_error_location_;
     75   std::string unrecoverable_error_msg_;
     76 
     77  private:
     78   friend class Entry;
     79   DISALLOW_COPY_AND_ASSIGN(BaseTransaction);
     80 };
     81 
     82 }  // namespace syncable
     83 }  // namespace syncer
     84 
     85 #endif  // SYNC_SYNCABLE_SYNCABLE_BASE_TRANSACTION_H_
     86