| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| **/ |
| |
| #ifndef QUICKSTEP_STORAGE_FILE_MANAGER_HPP_ |
| #define QUICKSTEP_STORAGE_FILE_MANAGER_HPP_ |
| |
| #include <cstddef> |
| #include <string> |
| |
| #include "storage/StorageBlockInfo.hpp" |
| #include "utility/Macros.hpp" |
| #include "utility/StringUtil.hpp" |
| |
| namespace quickstep { |
| |
| /** \addtogroup Storage |
| * @{ |
| */ |
| |
| /** |
| * @brief A class which manages file I/Os between memory and |
| * the persistent storage. |
| **/ |
| class FileManager { |
| public: |
| /** |
| * @brief Constructor. |
| * |
| * @param storage_path the filesystem directory where blocks have persistent |
| * storage. It is expected to end with a path separator (e.g., '\\' |
| * for Windows or '/' for POSIX systems). |
| * @param block_domain The domain of a block id. |
| **/ |
| explicit FileManager(const std::string &storage_path) |
| : storage_path_(storage_path) {} |
| |
| /** |
| * @brief Virtual destructor. |
| **/ |
| virtual ~FileManager() {} |
| |
| /** |
| * @brief Get a block or blob's relative filename, which uses storage_path_ |
| * as a path prefix. |
| * |
| * @param block The id of the block or blob. |
| * @return The relative filename for the given id. |
| **/ |
| virtual std::string blockFilename(const block_id block) const { |
| std::string filepath(storage_path_); |
| filepath.append("qsblk_"); |
| filepath.append(ToZeroPaddedString(BlockIdUtil::Domain(block), kBlockIdDomainLengthInDigits)); |
| filepath.append("_"); |
| filepath.append(ToZeroPaddedString(BlockIdUtil::Counter(block), kBlockIdCounterLengthInDigits)); |
| filepath.append(".qsb"); |
| |
| return filepath; |
| } |
| |
| /** |
| * @brief Get the highest block counter in the persistent storage. |
| * @exception CorruptPersistentStorage The storage directory layout is not |
| * in the expected format. |
| * |
| * @param domain The domain of a block or blob. |
| * @return The highest block-id in the persistent storage. Return 0 if no |
| * block files found for the current domain. |
| **/ |
| virtual block_id_counter getMaxUsedBlockCounter(const block_id_domain block_domain) const = 0; |
| |
| /** |
| * @brief Get the size of a block or blob in slots. |
| * |
| * @param block The id of the block or blob. |
| * @exception CorruptPersistentStorage The storage directory layout is not |
| * in the expected format. |
| * |
| * @return The number of slots for the given id (0 if it doesn't |
| * exist). |
| **/ |
| virtual std::size_t numSlots(const block_id block) const = 0; |
| |
| /** |
| * @brief Delete a block or blob's file. |
| * |
| * @param block The id of the block or blob to delete. |
| * |
| * @return False if the block exists but is failed to delete. True |
| * if the block is successfully deleted OR is not found. |
| **/ |
| virtual bool deleteBlockOrBlob(const block_id block) = 0; |
| |
| /** |
| * @brief Read a block or blob's file from the persistent storage. |
| * |
| * @param block The id of the block or blob to read. |
| * @param buffer The data contents of the block or blob to read. |
| * @param length The number of bytes to read. It should be multiple of |
| * kSlotSizeBytes. |
| * |
| * @return False if the block is not found in the persistent storage OR |
| * fails to load. True if the block is successfully loaded to memory. |
| **/ |
| virtual bool readBlockOrBlob(const block_id block, void *buffer, const std::size_t length) = 0; |
| |
| /** |
| * @brief Write a block or blob in memory to the persistent storage. |
| * |
| * @param block The id of the block or blob to write. |
| * @param buffer The data content of the block or blob to write. |
| * @param length The number of bytes to write. It should be multiple of |
| * kSlotSizeBytes. |
| * |
| * @return False if the block fails to write to the persistent storage. True |
| * if the block is written successfully. |
| **/ |
| virtual bool writeBlockOrBlob(const block_id block, const void *buffer, const std::size_t length) = 0; |
| |
| protected: |
| // File system path where block files are stored. Fixed when FileManager |
| // is created. |
| const std::string storage_path_; |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(FileManager); |
| }; |
| |
| /** @} */ |
| |
| } // namespace quickstep |
| |
| #endif // QUICKSTEP_STORAGE_FILE_MANAGER_HPP_ |