gistfile1.txt

    private void loadFromDiskLocked() {
//(snip)
        if (mBackupFile.exists()) {
            mFile.delete();
            mBackupFile.renameTo(mFile);
        }
//(snip)
        if (FileUtils.getFileStatus(mFile.getPath(), stat) && mFile.canRead()) {
//(snip) ここでファイルから読み込む
        }
//(snip)
    }

    // Note: must hold mWritingToDiskLock
    private void writeToFile(MemoryCommitResult mcr) {
        // Rename the current file so it may be used as a backup during the next read
        if (mFile.exists()) {
//(snip)
            if (!mBackupFile.exists()) {
                if (!mFile.renameTo(mBackupFile)) {
                    Log.e(TAG, "Couldn't rename file " + mFile
                          + " to backup file " + mBackupFile);
                    mcr.setDiskWriteResult(false);
                    return;
                }
            } else {
                mFile.delete();
            }
        }

        // Attempt to write the file, delete the backup and return true as atomically as
        // possible.  If any exception occurs, delete the new file; next time we will restore
        // from the backup.
        try {
            FileOutputStream str = createFileOutputStream(mFile);
//(snip)
            // Writing was successful, delete the backup file if there is one.
            mBackupFile.delete();
//(snip)
            return;
        } catch (XmlPullParserException e) {
            Log.w(TAG, "writeToFile: Got exception:", e);
        } catch (IOException e) {
            Log.w(TAG, "writeToFile: Got exception:", e);
        }
        // Clean up an unsuccessfully written file
        if (mFile.exists()) {
            if (!mFile.delete()) {
                Log.e(TAG, "Couldn't clean up partially-written file " + mFile);
            }
        }
//(snip)
    }