[SyncFS] Add per-URL promote of demoted changes in LocalFileChangeTracker

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 113 matching lines @@
                                SYNC_FILE_TYPE_DIRECTORY));
 }
 
 void LocalFileChangeTracker::OnRemoveDirectory(const FileSystemURL& url) {
   RecordChange(url, FileChange(FileChange::FILE_CHANGE_DELETE,
                                SYNC_FILE_TYPE_DIRECTORY));
 }
 
 void LocalFileChangeTracker::GetNextChangedURLs(
     std::deque<FileSystemURL>* urls, int max_urls) {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(urls);
-  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   urls->clear();
   // Mildly prioritizes the URLs that older changes and have not been updated
   // for a while.
   for (ChangeSeqMap::iterator iter = change_seqs_.begin();
        iter != change_seqs_.end() &&
        (max_urls == 0 || urls->size() < static_cast<size_t>(max_urls));
        ++iter) {
     urls->push_back(iter->second);
   }
 }
@@ skipping 20 matching lines @@
   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(file_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(!ContainsKey(mirror_changes_, url));
   mirror_changes_[url] = ChangeInfo();
 }
 
 void LocalFileChangeTracker::RemoveMirrorAndCommitChangesForURL(
     const fileapi::FileSystemURL& url) {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   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) {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   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);
 }
 
 void LocalFileChangeTracker::DemoteChangesForURL(
     const fileapi::FileSystemURL& url) {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   FileChangeMap::iterator found = changes_.find(url);
   if (found == changes_.end())
     return;
   FileChangeList changes = found->second.change_list;
 
   mirror_changes_.erase(url);
   change_seqs_.erase(found->second.change_seq);
   changes_.erase(found);
 
   FileChangeList::List change_list = changes.list();
   while (!change_list.empty()) {
     RecordChangeToChangeMaps(url, change_list.front(), 0,
                              &demoted_changes_, NULL);
     change_list.pop_front();
   }
 }
 
+void LocalFileChangeTracker::PromoteDemotedChangesForURL(
+    const fileapi::FileSystemURL& url) {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
+
+  FileChangeMap::iterator iter = demoted_changes_.find(url);
+  if (iter == demoted_changes_.end())
+    return;
+
+  FileChangeList::List change_list = iter->second.change_list.list();
+  // Make sure that this URL is in no queues.
+  DCHECK(!ContainsKey(changes_, url));
+  DCHECK(!ContainsKey(mirror_changes_, url));
+
+  demoted_changes_.erase(iter);
+
+  while (!change_list.empty()) {
+    RecordChange(url, change_list.front());
+    change_list.pop_front();
+  }
+}
+
 bool LocalFileChangeTracker::PromoteDemotedChanges() {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   if (demoted_changes_.empty())
     return false;
-  for (FileChangeMap::iterator iter = demoted_changes_.begin();
-       iter != demoted_changes_.end();) {
-    fileapi::FileSystemURL url = iter->first;
-    FileChangeList::List change_list = iter->second.change_list.list();
-    demoted_changes_.erase(iter++);
-
-    // Make sure that this URL is in no queues.
-    DCHECK(!ContainsKey(changes_, url));
-    DCHECK(!ContainsKey(demoted_changes_, url));
-    DCHECK(!ContainsKey(mirror_changes_, url));
-
-    while (!change_list.empty()) {
-      RecordChange(url, change_list.front());
-      change_list.pop_front();
-    }
+  while (!demoted_changes_.empty()) {
+    fileapi::FileSystemURL url = demoted_changes_.begin()->first;
+    PromoteDemotedChangesForURL(url);
   }
-  demoted_changes_.clear();
   return true;
 }
 
 SyncStatusCode LocalFileChangeTracker::Initialize(
     FileSystemContext* file_system_context) {
   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   DCHECK(!initialized_);
   DCHECK(file_system_context);
 
   SyncStatusCode status = CollectLastDirtyChanges(file_system_context);
@@ skipping 33 matching lines @@
   tracker_db_->WriteBatch(batch.Pass());
   UpdateNumChanges();
 }
 
 void LocalFileChangeTracker::UpdateNumChanges() {
   base::AutoLock lock(num_changes_lock_);
   num_changes_ = static_cast<int64>(change_seqs_.size());
 }
 
 void LocalFileChangeTracker::GetAllChangedURLs(FileSystemURLSet* urls) {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   std::deque<FileSystemURL> url_deque;
   GetNextChangedURLs(&url_deque, 0);
   urls->clear();
   urls->insert(url_deque.begin(), url_deque.end());
 }
 
 void LocalFileChangeTracker::DropAllChanges() {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   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);
 }
 
 SyncStatusCode LocalFileChangeTracker::ClearDirtyOnDatabase(
     const FileSystemURL& url) {
+  DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
   std::string serialized_url;
   if (!SerializeSyncableFileSystemURL(url, &serialized_url))
     return SYNC_FILE_ERROR_INVALID_URL;
 
   return tracker_db_->ClearDirty(serialized_url);
 }
 
 SyncStatusCode LocalFileChangeTracker::CollectLastDirtyChanges(
     FileSystemContext* file_system_context) {
   DCHECK(file_task_runner_->RunsTasksOnCurrentThread());
@@ skipping 68 matching lines @@
     RecordChangeToChangeMaps(url, change, 0, &demoted_changes_, NULL);
     return;
   }
   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();
 }
 
+// static
 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);
@@ skipping 153 matching lines @@
   if (!status.ok() && !status.IsNotFound()) {
     HandleError(FROM_HERE, status);
     db_status_ = LevelDBStatusToSyncStatusCode(status);
     db_.reset();
     return db_status_;
   }
   return SYNC_STATUS_OK;
 }
 
 }  // namespace sync_file_system