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#ifndef MOZC_BASE_CONFIG_FILE_STREAM_H_
#define MOZC_BASE_CONFIG_FILE_STREAM_H_

#include "base/file_stream.h"

namespace mozc {

// TODO(taku, komatsu) move ConfigFileStream to config/ directory?

// A class for user-configurable file object
//
// read filename and return istream object.
// filename format:
//
// A) system file embedded in .exe file
//   system://ms-ime.tsv
//   system://kotoeri.tsv
//
// B) user file. expaneded into $(USER_PROFILE_DIR)/file_name
//   user://foo.tsv
//   user://foo.bar
//
// C) file -- should only be enabled in debug build
//   file:///foo/bar/foo.tsv
//
// D) on-memory -- for debug.  Does not store to the disk at all.
//   memory://foo.tsv
//   memory://foo.bar
//
class ConfigFileStream {
 public:
  static istream *Open(const string &filename) {
    return Open(filename, ios_base::in);
  }

  static istream *Open(const string &filename,
                       ios_base::openmode mode);

  // Update the specified config filename (formatted as above) with
  // the |new_contents| atomically.  Returns true if the update
  // succeeds.
  static bool AtomicUpdate(const string &filename,
                           const string &new_contents);

  // if prefix is system:// or memory:// return "";
  static string GetFileName(const string &filename);

  // Clear all memory:// files.  This is a utility method for testing.
  static void ClearOnMemoryFiles();
};
}  // namespace mozc

#endif  // MOZC_BASE_CONFIG_FILE_STREAM_H_