drive: Add ResourceMetadataStorage::Iterator::GetCacheEntry()

chrome/browser/chromeos/drive/resource_metadata_storage.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/chromeos/drive/resource_metadata_storage.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ skipping 103 matching lines @@
   base::ThreadRestrictions::AssertIOAllowed();
   return !it_->Valid();
 }
 
 const ResourceEntry& ResourceMetadataStorage::Iterator::Get() const {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(!IsAtEnd());
   return entry_;
 }
 
+bool ResourceMetadataStorage::Iterator::GetCacheEntry(
+    FileCacheEntry* cache_entry) {
+  base::ThreadRestrictions::AssertIOAllowed();
+  DCHECK(!IsAtEnd());
+
+  // Try to seek to the cache entry.
+  std::string current_key = it_->key().ToString();
+  std::string cache_entry_key = GetCacheEntryKey(current_key);
+  it_->Seek(leveldb::Slice(cache_entry_key));
+
+  bool success = it_->Valid() &&
+      it_->key().compare(cache_entry_key) == 0 &&
+      cache_entry->ParseFromArray(it_->value().data(), it_->value().size());
+
+  // Seek back to the original position.
+  it_->Seek(leveldb::Slice(current_key));
+  DCHECK(!IsAtEnd());
+  DCHECK_EQ(current_key, it_->key().ToString());
+
+  return success;
+}
+
 void ResourceMetadataStorage::Iterator::Advance() {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(!IsAtEnd());
 
   for (it_->Next() ; it_->Valid(); it_->Next()) {
     if (!IsChildEntryKey(it_->key()) &&
         !IsCacheEntryKey(it_->key()) &&
         entry_.ParseFromArray(it_->value().data(), it_->value().size()))
       break;
   }
@@ skipping 476 matching lines @@
   if (!it->status().ok() || num_child_entries != num_entries_with_parent) {
     DLOG(ERROR) << "Error during checking resource map. status = "
                 << it->status().ToString();
     return false;
   }
   return true;
 }
 
 }  // namespace internal
 }  // namespace drive