GDataDB support with leveldb.

chrome/browser/chromeos/gdata/gdata_db.h

+// Copyright (c) 2012 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_GDATA_GDATA_DB_H_
+#define CHROME_BROWSER_CHROMEOS_GDATA_GDATA_DB_H_
+#pragma once
+
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+
+class FilePath;
+
+namespace gdata {
+
+class GDataEntry;
+class GDataDBIter;
+
+// GData Database interface class.
+class GDataDB {
+ public:
+  enum Status {
+    DB_OK = 0,
+    DB_KEY_NOT_FOUND,  // Key not found.
+    DB_CORRUPTION,  // Database file corrupt.
+    DB_IO_ERROR,  // File I/O error.
+    DB_INTERNAL_ERROR,
+  };
+
+  virtual ~GDataDB() {}
+
+  // Puts |entry| to the database.
+  virtual Status Put(const GDataEntry& entry) = 0;
+
+  // Deletes a database entry with key |resource_id| or |path| respectively.
+  virtual Status DeleteByResourceId(const std::string& resource_id) = 0;
+  virtual Status DeleteByPath(const FilePath& path) = 0;
+
+  // Fetches a GDataEntry* by key |resource_id| or |path| respectively.
+  virtual Status GetByResourceId(const std::string& resource_id,
+                                 scoped_ptr<GDataEntry>* entry) = 0;
+  virtual Status GetByPath(const FilePath& path,
+                           scoped_ptr<GDataEntry>* entry) = 0;
+
+  // An iterator to fetch all GDataEntry's under |path|.

[satorux1, 2012/04/24 21:47:57]

nit: Creates an iterator.

btw, can this be NULL? might want to document about it.

[achuithb, 2012/04/24 22:15:13]

It cannot be NULL, unless malloc fails. I don't know how to document this.
Should I write - Cannot be NULL?

[satorux1, 2012/04/24 22:34:50]

I'd say "Will not return NULL".

[achuithb, 2012/04/24 23:47:20]

Done.

+  virtual scoped_ptr<GDataDBIter> CreateIterator(const FilePath& path) = 0;
+
+ protected:
+  GDataDB() {}
+};
+
+// GData Database Iterator interface class.
+class GDataDBIter {
+ public:
+  virtual ~GDataDBIter() {}
+
+  // Fetches the next |entry| in the iteration sequence. Returns false when
+  // there are no more entries.
+  virtual bool GetNext(std::string* path, scoped_ptr<GDataEntry>* entry) = 0;
+
+ protected:
+  GDataDBIter() {}
+};
+
+}  // namespace gdata
+
+#endif  // CHROME_BROWSER_CHROMEOS_GDATA_GDATA_DB_H_