[SyncFS] Introduce counters in LevelDBWrapper

chrome/browser/sync_file_system/drive_backend/leveldb_wrapper.cc

 // Copyright 2014 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/drive_backend/leveldb_wrapper.h"
 
 #include <map>
 #include <set>
 #include <string>
 
@@ skipping 60 matching lines @@
   DCHECK(Valid());
 
   const std::string key_str = key().ToString();
   Transaction deletion(DELETE_OPERATION, std::string());
   map_iterator_ = db_->pending_.insert(map_iterator_,
                                        std::make_pair(key_str, deletion));
   // In case that |db_->pending_| already had an entry for the key, we have to
   // update the value.
   map_iterator_->second = deletion;
 
+  ++(db_->num_deletes_);
+
   AdvanceIterators();
 }
 
 leveldb::Slice LevelDBWrapper::Iterator::key() {
   DCHECK(Valid());
 
   if (!db_iterator_->Valid())
     return map_iterator_->first;
   if (map_iterator_ == db_->pending_.end())
     return db_iterator_->key();
@@ skipping 44 matching lines @@
 
   while (map_iterator_ != db_->pending_.end() &&
          map_iterator_->second.first == DELETE_OPERATION)
     ++map_iterator_;
 }
 
 // ---------------------------------------------------------------------------
 // LevelDBWrapper class
 // ---------------------------------------------------------------------------
 LevelDBWrapper::LevelDBWrapper(scoped_ptr<leveldb::DB> db)
-    : db_(db.Pass()) {
+    : db_(db.Pass()), num_puts_(0), num_deletes_(0) {
   DCHECK(db_);
 }
 
 LevelDBWrapper::~LevelDBWrapper() {}
 
-void LevelDBWrapper::Put(const std::string& key,
-                         const std::string& value) {
+void LevelDBWrapper::Put(const std::string& key, const std::string& value) {
   pending_[key] = Transaction(PUT_OPERATION, value);
+  ++num_puts_;
 }
 
 void LevelDBWrapper::Delete(const std::string& key) {
   pending_[key] = Transaction(DELETE_OPERATION, std::string());
+  ++num_deletes_;
 }
 
 leveldb::Status LevelDBWrapper::Get(const std::string& key,
                                     std::string* value) {
   PendingOperationMap::iterator itr = pending_.find(key);
   if (itr == pending_.end())
     return db_->Get(leveldb::ReadOptions(), key, value);
 
   const Transaction& transaction = itr->second;
   switch (transaction.first) {
@@ skipping 30 matching lines @@
   leveldb::Status status = db_->Write(leveldb::WriteOptions(), &batch);
   // TODO(peria): Decide what to do depending on |status|.
   if (status.ok())
     Clear();
 
   return status;
 }
 
 void LevelDBWrapper::Clear() {
   pending_.clear();
+  num_puts_ = 0;
+  num_deletes_ = 0;
 }
 
 leveldb::DB* LevelDBWrapper::GetLevelDB() {
   return db_.get();
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system