Database support for GDataDirectoryService.

chrome/browser/chromeos/gdata/gdata_files.h

Index: chrome/browser/chromeos/gdata/gdata_files.h
===================================================================
--- chrome/browser/chromeos/gdata/gdata_files.h	(revision 148059)
+++ chrome/browser/chromeos/gdata/gdata_files.h	(working copy)
@@ -5,6 +5,7 @@
 #ifndef CHROME_BROWSER_CHROMEOS_GDATA_GDATA_FILES_H_
 #define CHROME_BROWSER_CHROMEOS_GDATA_GDATA_FILES_H_
 
+#include <leveldb/db.h>
 #include <map>
 #include <string>
 
@@ -21,6 +22,10 @@
 #include "chrome/browser/profiles/profile_keyed_service.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
+namespace base {
+class SequencedTaskRunner;
+}  // namespace base
+
 namespace gdata {
 
 class GDataFile;
@@ -322,6 +327,7 @@
   DISALLOW_COPY_AND_ASSIGN(GDataDirectory);
 };
 
+// TODO(achuith,hashimoto,satorux): Move this to a separate file.
 // Class to handle GDataEntry* lookups, add/remove GDataEntry*.
 class GDataDirectoryService {
  public:
@@ -376,13 +382,33 @@
   void SerializeToString(std::string* serialized_proto) const;
   bool ParseFromString(const std::string& serialized_proto);
 
+  // Restore from and save to database.
+  void InitFromDB(const FilePath& db_path,
+                  base::SequencedTaskRunner* blocking_task_runner);

[satorux1, 2012/07/24 16:30:34]

Loading from DB can fail, right? If so, the caller of this function should have
a way to tell if it's failed. Maybe add a callback parameter which is called
upon completion/failure?

+  void SaveResourceMapToDB();

[hashimoto, 2012/07/24 08:41:51]

Where is this method used?

+
  private:
   // A map table of file's resource string to its GDataFile* entry.
   typedef std::map<std::string, GDataEntry*> ResourceMap;
+  // Map of resource id and serialized GDataEntry.
+  typedef std::map<std::string, std::string> SerializedMap;
 
-  scoped_ptr<GDataDirectory> root_;  // Stored in the serialized proto.
+  // Helper functions for restoring from and saving to the database.
+  void ReadFromDBOnBlockingThread(const FilePath& db_path,
+                                  SerializedMap* serialized_resources);
+  void InitDBOnBlockingThread(const FilePath& db_path);
+  void InitResourceMapOnUIThread(SerializedMap* serialized_resources);
+  void SaveSerializedToDBOnBlockingThread(
+      const SerializedMap& serialized_resources);
+
+  scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
+
   ResourceMap resource_map_;
+  scoped_ptr<leveldb::DB> level_db_;
+  FilePath db_path_;
 
+  scoped_ptr<GDataDirectory> root_;  // Stored in the serialized proto.
+
   base::Time last_serialized_;
   size_t serialized_size_;
   int largest_changestamp_;  // Stored in the serialized proto.