Add SNAPSHOT sync mode to LocalFileSyncContext::PrepareForSync

chrome/browser/sync_file_system/local/local_file_change_tracker.cc

 // Copyright 2013 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_file_system/local/local_file_change_tracker.h"
 
 #include <queue>
 
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 132 matching lines @@
   DCHECK(changes);
   changes->clear();
   FileChangeMap::iterator found = changes_.find(url);
   if (found == changes_.end())
     return;
   *changes = found->second.change_list;
 }
 
 void LocalFileChangeTracker::ClearChangesForURL(const FileSystemURL& url) {
   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
-  // TODO(nhiroki): propagate the error code (see http://crbug.com/152127).
   ClearDirtyOnDatabase(url);
-
+  mirror_changes_.erase(url);
   FileChangeMap::iterator found = changes_.find(url);
   if (found == changes_.end())
     return;
   change_seqs_.erase(found->second.change_seq);
   changes_.erase(found);
   UpdateNumChanges();
 }
 
+void LocalFileChangeTracker::CreateFreshMirrorForURL(
+    const fileapi::FileSystemURL& url) {
+  DCHECK(!ContainsKey(mirror_changes_, url));
+  mirror_changes_[url] = ChangeInfo();
+}
+
+void LocalFileChangeTracker::RemoveMirrorAndCommitChangesForURL(
+    const fileapi::FileSystemURL& url) {
+  FileChangeMap::iterator found = mirror_changes_.find(url);
+  if (found == mirror_changes_.end())
+    return;
+  mirror_changes_.erase(found);
+
+  if (ContainsKey(changes_, url))
+    MarkDirtyOnDatabase(url);
+  else
+    ClearDirtyOnDatabase(url);
+  UpdateNumChanges();
+}
+
+void LocalFileChangeTracker::ResetToMirrorAndCommitChangesForURL(
+    const fileapi::FileSystemURL& url) {
+  FileChangeMap::iterator found = mirror_changes_.find(url);
+  if (found == mirror_changes_.end() || found->second.change_list.empty()) {
+    ClearChangesForURL(url);
+    return;
+  }
+  const ChangeInfo& info = found->second;
+  change_seqs_[info.change_seq] = url;
+  changes_[url] = info;
+  RemoveMirrorAndCommitChangesForURL(url);
+}
+
 SyncStatusCode LocalFileChangeTracker::Initialize(
     FileSystemContext* file_system_context) {
   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(!initialized_);
   DCHECK(file_system_context);
 
   SyncStatusCode status = CollectLastDirtyChanges(file_system_context);
   if (status == SYNC_STATUS_OK)
     initialized_ = true;
   return status;
 }
 
 void LocalFileChangeTracker::UpdateNumChanges() {
   base::AutoLock lock(num_changes_lock_);
   num_changes_ = static_cast<int64>(change_seqs_.size());
 }
 
 void LocalFileChangeTracker::GetAllChangedURLs(FileSystemURLSet* urls) {
   std::deque<FileSystemURL> url_deque;
   GetNextChangedURLs(&url_deque, 0);
   urls->clear();
   urls->insert(url_deque.begin(), url_deque.end());
 }
 
 void LocalFileChangeTracker::DropAllChanges() {
   changes_.clear();
   change_seqs_.clear();
+  mirror_changes_.clear();
 }
 
 SyncStatusCode LocalFileChangeTracker::MarkDirtyOnDatabase(
     const FileSystemURL& url) {
   std::string serialized_url;
   if (!SerializeSyncableFileSystemURL(url, &serialized_url))
     return SYNC_FILE_ERROR_INVALID_URL;
 
   return tracker_db_->MarkDirty(serialized_url);
 }
@@ skipping 70 matching lines @@
         LOG(WARNING) << "Failed to access local file.";
         break;
     }
   }
   return SYNC_STATUS_OK;
 }
 
 void LocalFileChangeTracker::RecordChange(
     const FileSystemURL& url, const FileChange& change) {
   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
-  ChangeInfo& info = changes_[url];
-  if (info.change_seq >= 0)
-    change_seqs_.erase(info.change_seq);
-  info.change_list.Update(change);
-  if (info.change_list.empty()) {
-    changes_.erase(url);
-    UpdateNumChanges();
-    return;
-  }
-  info.change_seq = current_change_seq_++;
-  change_seqs_[info.change_seq] = url;
+  int change_seq = current_change_seq_++;
+  RecordChangeToChangeMaps(url, change, change_seq, &changes_, &change_seqs_);
+  if (ContainsKey(mirror_changes_, url))
+    RecordChangeToChangeMaps(url, change, change_seq, &mirror_changes_, NULL);
   UpdateNumChanges();
 }
 
+void LocalFileChangeTracker::RecordChangeToChangeMaps(
+    const FileSystemURL& url,
+    const FileChange& change,
+    int new_change_seq,
+    FileChangeMap* changes,
+    ChangeSeqMap* change_seqs) {
+  ChangeInfo& info = (*changes)[url];
+  if (info.change_seq >= 0 && change_seqs)
+    change_seqs->erase(info.change_seq);
+  info.change_list.Update(change);
+  if (info.change_list.empty()) {
+    changes->erase(url);
+    return;
+  }
+  info.change_seq = new_change_seq;
+  if (change_seqs)
+    (*change_seqs)[info.change_seq] = url;
+}
+
 // TrackerDB -------------------------------------------------------------------
 
 LocalFileChangeTracker::TrackerDB::TrackerDB(const base::FilePath& base_path)
   : base_path_(base_path),
     db_status_(SYNC_STATUS_OK) {}
 
 SyncStatusCode LocalFileChangeTracker::TrackerDB::Init(
     RecoveryOption recovery_option) {
   if (db_.get() && db_status_ == SYNC_STATUS_OK)
     return SYNC_STATUS_OK;
@@ skipping 115 matching lines @@
       db_.reset();
       return db_status_;
     }
     dirty_files->push(url);
     iter->Next();
   }
   return SYNC_STATUS_OK;
 }
 
 }  // namespace sync_file_system