[Sync] Refactor sync datatype error handling.

chrome/browser/sync/glue/model_associator.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_SYNC_GLUE_MODEL_ASSOCIATOR_H_
 #define CHROME_BROWSER_SYNC_GLUE_MODEL_ASSOCIATOR_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "chrome/browser/sync/syncable/model_type.h"
 
+class SyncError;
+
 namespace sync_api {
 class BaseNode;
 }
 
 namespace browser_sync {
 
 // This represents the fundamental operations used for model association that
 // are common to all ModelAssociators and do not depend on types of the models
 // being associated.
 class AssociatorInterface {
  public:
   virtual ~AssociatorInterface() {}
 
   // Iterates through both the sync and the chrome model looking for
   // matched pairs of items. After successful completion, the models
   // should be identical and corresponding. Returns true on
   // success. On failure of this step, we should abort the sync
   // operation and report an error to the user.
-  virtual bool AssociateModels() = 0;
+  virtual bool AssociateModels(SyncError* error) = 0;

[akalin, 2011/07/25 22:43:13]

Change these to return SyncErrors too?  (and subclasses)

[Nicolas Zea, 2011/07/25 23:08:19]

Since this is already an established (and now deprecated API) that relies on
[Dis]AssociateModels returning true/false on success/error, and because we're
planning on switching everything over to the new API anyways, I'd prefer to do
the less intrusive change for now (just adding an extra parameter), if that's
ok. I've added a TODO for once we have less datatypes reliant on this approach.

[akalin, 2011/07/25 23:49:32]

Yeah, for practicality's sake I guess we can leave it like this.  Although I
have a feeling the old-style APIs are gonna stick around for a while. :|

 
   // Clears all the associations between the chrome and sync models.
-  virtual bool DisassociateModels() = 0;
+  virtual bool DisassociateModels(SyncError* error) = 0;
 
   // The has_nodes out parameter is set to true if the sync model has
   // nodes other than the permanent tagged nodes.  The method may
   // return false if an error occurred.
   virtual bool SyncModelHasUserCreatedNodes(bool* has_nodes) = 0;
 
   // Calling this method while AssociateModels() is in progress will
   // cause the method to exit early with a "false" return value.  This
   // is useful for aborting model associations for shutdown.  This
   // method is only implemented for model associators that are invoked
@@ skipping 37 matching lines @@
   // Associates the given chrome node with the given sync id.
   virtual void Associate(const Node* node, int64 sync_id) = 0;
 
   // Remove the association that corresponds to the given sync id.
   virtual void Disassociate(int64 sync_id) = 0;
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_MODEL_ASSOCIATOR_H_