| // Copyright 2010-2015, Google Inc. |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef MOZC_STORAGE_STORAGE_INTERFACE_H_ |
| #define MOZC_STORAGE_STORAGE_INTERFACE_H_ |
| |
| #include <string> |
| |
| #include "base/port.h" |
| |
| namespace mozc { |
| namespace storage { |
| |
| class StorageInterface { |
| public: |
| // Binds |filename| to the storage but the interpretation of the |
| // |filename| depends on the implementaion. implementations can |
| // - ignore the specified |filename|. |
| // - load the existing data from |filename|. |
| // - return true if the specified |filename| does not exist. |
| // Despite its name, an implementation may not keep the underlaying |
| // data storage specified by |filename| opened. |
| // StorageInterface::Sync may try to open |filename| again but it |
| // may fail even when this method returns true. |
| virtual bool Open(const string &filename) = 0; |
| |
| // Flushes on-memory data into persistent storage (usually on |
| // disk) specified by |filename|. |
| virtual bool Sync() = 0; |
| |
| // Looks up key and returns the value. |
| // If key is not found, returns false. |
| // It is not guranteed that the data is synced to the disk. |
| virtual bool Lookup(const string &key, string *value) const = 0; |
| |
| // Inserts key and value. |
| // It is not guranteed that the data is synced to the disk. |
| virtual bool Insert(const string &key, const string &value) = 0; |
| |
| // Erases the key-value pair specified by |key|. |
| // It is not guranteed that the data is synced to the disk |
| virtual bool Erase(const string &key) = 0; |
| |
| // clears internal keys and values |
| // Sync() is automatically called. |
| virtual bool Clear() = 0; |
| |
| // Returns the number of keys, not a number of bytes. |
| virtual size_t Size() const = 0; |
| |
| StorageInterface() {} |
| virtual ~StorageInterface() {} |
| }; |
| |
| } // namespace storage |
| } // namespace mozc |
| |
| #endif // MOZC_STORAGE_STORAGE_INTERFACE_H_ |