Sync: Change Local IDs to GUID based to avoid ID collision

sync/syncable/directory_backing_store.cc

 // Copyright 2012 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.
 
 #include "sync/syncable/directory_backing_store.h"
 
 #include "build/build_config.h"
 
 #include <limits>
 
@@ skipping 273 matching lines @@
 
   if (!DeleteEntries(DELETE_JOURNAL_TABLE, snapshot.delete_journals_to_purge))
     return false;
 
   if (save_info) {
     const Directory::PersistedKernelInfo& info = snapshot.kernel_info;
     sql::Statement s1(db_->GetCachedStatement(
             SQL_FROM_HERE,
             "UPDATE share_info "
             "SET store_birthday = ?, "
-            "next_id = ?, "
             "bag_of_chips = ?"));
     s1.BindString(0, info.store_birthday);
-    s1.BindInt64(1, info.next_id);
-    s1.BindBlob(2, info.bag_of_chips.data(), info.bag_of_chips.size());
+    s1.BindBlob(1, info.bag_of_chips.data(), info.bag_of_chips.size());
 
     if (!s1.Run())
       return false;
     DCHECK_EQ(db_->GetLastChangeCount(), 1);
 
     sql::Statement s2(db_->GetCachedStatement(
             SQL_FROM_HERE,
             "INSERT OR REPLACE "
             "INTO models (model_id, "
                          "progress_marker, "
@@ skipping 259 matching lines @@
   SafeDropTable("temp_share_info");
   if (!CreateShareInfoTable(true))
     return false;
 
   // TODO(rlarocque, 124140): Remove notification_state.
   if (!db_->Execute(
           "INSERT INTO temp_share_info (id, name, store_birthday, "
           "db_create_version, db_create_time, next_id, cache_guid,"
           "notification_state, bag_of_chips) "
           "SELECT id, name, store_birthday, db_create_version, "
           "db_create_time, next_id, cache_guid, notification_state, "

[maniscalco, 2015/05/14 15:54:20]

Just wanted to confirm that it's OK to leave this use of next_id here for now. 
In a future CL when we remove next_id completely, we'll need to update this
method to effectively drop the column, right?

           "bag_of_chips "
           "FROM share_info"))
     return false;
 
   SafeDropTable("share_info");
   if (!db_->Execute("ALTER TABLE temp_share_info RENAME TO share_info"))
     return false;
 
   needs_column_refresh_ = false;
   return true;
@@ skipping 50 matching lines @@
     // A null kernel is evidence of external data corruption.
     if (!kernel)
       return false;
     delete_journals->insert(kernel.release());
   }
   return s.Succeeded();
 }
 
 bool DirectoryBackingStore::LoadInfo(Directory::KernelLoadInfo* info) {
   {
-    sql::Statement s(
-        db_->GetUniqueStatement(
-            "SELECT store_birthday, next_id, cache_guid, bag_of_chips "
-            "FROM share_info"));
+    sql::Statement s(db_->GetUniqueStatement(
+        "SELECT store_birthday, cache_guid, bag_of_chips "
+        "FROM share_info"));
     if (!s.Step())
       return false;
 
     info->kernel_info.store_birthday = s.ColumnString(0);
-    info->kernel_info.next_id = s.ColumnInt64(1);
-    info->cache_guid = s.ColumnString(2);
-    s.ColumnBlobAsString(3, &(info->kernel_info.bag_of_chips));
+    info->cache_guid = s.ColumnString(1);
+    s.ColumnBlobAsString(2, &(info->kernel_info.bag_of_chips));
 
     // Verify there was only one row returned.
     DCHECK(!s.Step());
     DCHECK(s.Succeeded());
   }
 
   {
     sql::Statement s(
         db_->GetUniqueStatement(
             "SELECT model_id, progress_marker, "
@@ skipping 1007 matching lines @@
   DCHECK(CalledOnValidThread());
   DCHECK(!catastrophic_error_handler.is_null());
   catastrophic_error_handler_ = catastrophic_error_handler;
   sql::Connection::ErrorCallback error_callback =
       base::Bind(&OnSqliteError, catastrophic_error_handler_);
   db_->set_error_callback(error_callback);
 }
 
 }  // namespace syncable
 }  // namespace syncer