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// Copyright (c) 2006-2009 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 "chrome/browser/sync/engine/process_updates_command.h"
#include <vector>
#include "base/basictypes.h"
#include "chrome/browser/sync/engine/syncer.h"
#include "chrome/browser/sync/engine/syncer_proto_util.h"
#include "chrome/browser/sync/engine/syncer_util.h"
#include "chrome/browser/sync/engine/syncproto.h"
#include "chrome/browser/sync/sessions/sync_session.h"
#include "chrome/browser/sync/syncable/directory_manager.h"
#include "chrome/browser/sync/syncable/syncable.h"
using std::vector;
namespace browser_sync {
using sessions::SyncSession;
using sessions::StatusController;
ProcessUpdatesCommand::ProcessUpdatesCommand() {}
ProcessUpdatesCommand::~ProcessUpdatesCommand() {}
bool ProcessUpdatesCommand::ModelNeutralExecuteImpl(SyncSession* session) {
const GetUpdatesResponse& updates =
session->status_controller()->updates_response().get_updates();
const int update_count = updates.entries_size();
// Don't bother processing updates if there were none.
return update_count != 0;
}
void ProcessUpdatesCommand::ModelChangingExecuteImpl(SyncSession* session) {
syncable::ScopedDirLookup dir(session->context()->directory_manager(),
session->context()->account_name());
if (!dir.good()) {
LOG(ERROR) << "Scoped dir lookup failed!";
return;
}
StatusController* status = session->status_controller();
const sessions::UpdateProgress& progress(status->update_progress());
vector<sessions::VerifiedUpdate>::const_iterator it;
for (it = progress.VerifiedUpdatesBegin();
it != progress.VerifiedUpdatesEnd();
++it) {
const sync_pb::SyncEntity& update = it->second;
if (it->first != VERIFY_SUCCESS && it->first != VERIFY_UNDELETE)
continue;
switch (ProcessUpdate(dir, update)) {
case SUCCESS_PROCESSED:
case SUCCESS_STORED:
break;
default:
NOTREACHED();
break;
}
}
status->set_num_consecutive_errors(0);
// TODO(nick): The following line makes no sense to me.
status->set_syncing(true);
return;
}
namespace {
// Returns true if the entry is still ok to process.
bool ReverifyEntry(syncable::WriteTransaction* trans, const SyncEntity& entry,
syncable::MutableEntry* same_id) {
const bool deleted = entry.has_deleted() && entry.deleted();
const bool is_directory = entry.IsFolder();
const syncable::ModelType model_type = entry.GetModelType();
return VERIFY_SUCCESS == SyncerUtil::VerifyUpdateConsistency(trans,
entry,
same_id,
deleted,
is_directory,
model_type);
}
} // namespace
// Process a single update. Will avoid touching global state.
ServerUpdateProcessingResult ProcessUpdatesCommand::ProcessUpdate(
const syncable::ScopedDirLookup& dir,
const sync_pb::SyncEntity& proto_update) {
const SyncEntity& update = *static_cast<const SyncEntity*>(&proto_update);
using namespace syncable;
syncable::Id server_id = update.id();
const std::string name = SyncerProtoUtil::NameFromSyncEntity(update);
WriteTransaction trans(dir, SYNCER, __FILE__, __LINE__);
// Look to see if there's a local item that should recieve this update,
// maybe due to a duplicate client tag or a lost commit response.
syncable::Id local_id = SyncerUtil::FindLocalIdToUpdate(&trans, update);
// FindLocalEntryToUpdate has veto power.
if (local_id.IsNull()) {
return SUCCESS_PROCESSED; // The entry has become irrelevant.
}
SyncerUtil::CreateNewEntry(&trans, local_id);
// We take a two step approach. First we store the entries data in the
// server fields of a local entry and then move the data to the local fields
MutableEntry target_entry(&trans, GET_BY_ID, local_id);
// We need to run the Verify checks again; the world could have changed
// since VerifyUpdatesCommand.
if (!ReverifyEntry(&trans, update, &target_entry)) {
return SUCCESS_PROCESSED; // The entry has become irrelevant.
}
// If we're repurposing an existing local entry with a new server ID,
// change the ID now, after we're sure that the update can succeed.
if (local_id != server_id) {
DCHECK(!update.deleted());
SyncerUtil::ChangeEntryIDAndUpdateChildren(&trans, &target_entry,
server_id);
// When IDs change, versions become irrelevant. Forcing BASE_VERSION
// to zero would ensure that this update gets applied, but would indicate
// creation or undeletion if it were committed that way. Instead, prefer
// forcing BASE_VERSION to entry.version() while also forcing
// IS_UNAPPLIED_UPDATE to true. If the item is UNSYNCED, it's committable
// from the new state; it may commit before the conflict resolver gets
// a crack at it.
if (target_entry.Get(IS_UNSYNCED) || target_entry.Get(BASE_VERSION) > 0) {
// If either of these conditions are met, then we can expect valid client
// fields for this entry. When BASE_VERSION is positive, consistency is
// enforced on the client fields at update-application time. Otherwise,
// we leave the BASE_VERSION field alone; it'll get updated the first time
// we successfully apply this update.
target_entry.Put(BASE_VERSION, update.version());
}
// Force application of this update, no matter what.
target_entry.Put(IS_UNAPPLIED_UPDATE, true);
}
SyncerUtil::UpdateServerFieldsFromUpdate(&target_entry, update, name);
if (target_entry.Get(SERVER_VERSION) == target_entry.Get(BASE_VERSION) &&
!target_entry.Get(IS_UNSYNCED) &&
!target_entry.Get(IS_UNAPPLIED_UPDATE)) {
// If these don't match, it means that we have a different view of the
// truth from other clients. That's a sync bug, though we may be able
// to recover the next time this item commits.
LOG_IF(ERROR, !SyncerUtil::ServerAndLocalEntriesMatch(&target_entry))
<< target_entry;
}
return SUCCESS_PROCESSED;
}
} // namespace browser_sync
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