| // Copyright 2016 The Cobalt Authors. All Rights Reserved. |
| // |
| // Licensed 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. |
| |
| // Module Overview: Starboard Storage module |
| // |
| // Defines a Storage API. This is a simple, all-at-once BLOB storage |
| // and retrieval API that is intended for robust long-term storage. |
| // Some platforms have different mechanisms for this kind of storage, so this |
| // API exists to allow a client application to access this kind of storage. |
| // |
| // Note that there can be only one storage record and, thus, a maximum |
| // of one open storage record can exist. Attempting to open a second record |
| // will result in undefined behavior. |
| // |
| // These APIs are NOT expected to be thread-safe, so either call them from a |
| // single thread, or perform proper synchronization around all calls. |
| |
| #ifndef STARBOARD_STORAGE_H_ |
| #define STARBOARD_STORAGE_H_ |
| |
| #include "starboard/export.h" |
| #include "starboard/types.h" |
| #if SB_API_VERSION < 16 |
| #include "starboard/user.h" |
| #endif // SB_API_VERSION < 16 |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| // Private structure representing a single storage record. |
| typedef struct SbStorageRecordPrivate SbStorageRecordPrivate; |
| |
| // A handle to an open storage record. |
| typedef SbStorageRecordPrivate* SbStorageRecord; |
| |
| // Well-defined value for an invalid storage record handle. |
| #define kSbStorageInvalidRecord (SbStorageRecord) NULL |
| |
| // Returns whether the given storage record handle is valid. |
| static inline bool SbStorageIsValidRecord(SbStorageRecord record) { |
| return record != kSbStorageInvalidRecord; |
| } |
| |
| #if SB_API_VERSION < 16 |
| // Opens and returns the SbStorageRecord for |user| named |name|, blocking I/O |
| // on the calling thread until the open is completed. If |user| is not a valid |
| // |SbUser|, the function returns |kSbStorageInvalidRecord|. Will return an |
| // |SbStorageRecord| of size zero if the record does not yet exist. Opening an |
| // already-open |SbStorageRecord| has undefined behavior. |
| // |
| // If |name| is NULL, opens the default storage record for the user, like what |
| // would have been saved with the previous version of SbStorageOpenRecord. |
| // |
| // |user|: The user for which the storage record will be opened. |
| // |name|: The filesystem-safe name of the record to open. |
| SB_EXPORT SbStorageRecord SbStorageOpenRecord(SbUser user, const char* name); |
| #else // SB_API_VERSION < 16 |
| // Opens and returns the SbStorageRecord named |name|, blocking I/O |
| // on the calling thread until the open is completed. Will return an |
| // |SbStorageRecord| of size zero if the record does not yet exist. Opening an |
| // already-open |SbStorageRecord| has undefined behavior. |
| // |
| // If |name| is NULL, opens the default storage record, like what |
| // would have been saved with the previous version of SbStorageOpenRecord. |
| // |
| // |name|: The filesystem-safe name of the record to open. |
| SB_EXPORT SbStorageRecord SbStorageOpenRecord(const char* name); |
| #endif // SB_API_VERSION < 16 |
| |
| // Closes |record|, synchronously ensuring that all written data is flushed. |
| // This function performs blocking I/O on the calling thread. |
| // |
| // The return value indicates whether the operation succeeded. Storage writes |
| // should be as atomic as possible, so the record should either be fully |
| // written or deleted (or, even better, untouched). |
| // |
| // |record|: The storage record to close. |record| is invalid after this point, |
| // and subsequent calls referring to |record| will fail. |
| SB_EXPORT bool SbStorageCloseRecord(SbStorageRecord record); |
| |
| // Returns the size of |record|, or |-1| if there is an error. This function |
| // performs blocking I/O on the calling thread. |
| // |
| // |record|: The record to retrieve the size of. |
| SB_EXPORT int64_t SbStorageGetRecordSize(SbStorageRecord record); |
| |
| // Reads up to |data_size| bytes from |record|, starting at the beginning of |
| // the record. The function returns the actual number of bytes read, which |
| // must be <= |data_size|. The function returns |-1| in the event of an error. |
| // This function makes a best-effort to read the entire record, and it performs |
| // blocking I/O on the calling thread until the entire record is read or an |
| // error is encountered. |
| // |
| // |record|: The record to be read. |
| // |out_data|: The data read from the record. |
| // |data_size|: The amount of data, in bytes, to read. |
| SB_EXPORT int64_t SbStorageReadRecord(SbStorageRecord record, |
| char* out_data, |
| int64_t data_size); |
| |
| // Replaces the data in |record| with |data_size| bytes from |data|. This |
| // function always deletes any previous data in that record. The return value |
| // indicates whether the write succeeded. This function makes a best-effort to |
| // write the entire record, and it may perform blocking I/O on the calling |
| // thread until the entire record is written or an error is encountered. |
| // |
| // While |SbStorageWriteRecord()| may defer the persistence, |
| // |SbStorageReadRecord()| is expected to work as expected immediately |
| // afterwards, even without a call to |SbStorageCloseRecord()|. The data should |
| // be persisted after a short time, even if there is an unexpected process |
| // termination before |SbStorageCloseRecord()| is called. |
| // |
| // |record|: The record to be written to. |
| // |data|: The data to write to the record. |
| // |data_size|: The amount of |data|, in bytes, to write to the record. |
| SB_EXPORT bool SbStorageWriteRecord(SbStorageRecord record, |
| const char* data, |
| int64_t data_size); |
| |
| #if SB_API_VERSION < 16 |
| // Deletes the |SbStorageRecord| for |user| named |name|. The return value |
| // indicates whether the record existed and was successfully deleted. If the |
| // record did not exist or could not be deleted, the function returns |false|. |
| // |
| // If |name| is NULL, deletes the default storage record for the user, like what |
| // would have been deleted with the previous version of SbStorageDeleteRecord. |
| // |
| // This function must not be called while the user's storage record is open. |
| // This function performs blocking I/O on the calling thread. |
| // |
| // |user|: The user for whom the record will be deleted. |
| // |name|: The filesystem-safe name of the record to open. |
| SB_EXPORT bool SbStorageDeleteRecord(SbUser user, const char* name); |
| #else // SB_API_VERSION < 16 |
| // Deletes the |SbStorageRecord| named |name|. The return value |
| // indicates whether the record existed and was successfully deleted. If the |
| // record did not exist or could not be deleted, the function returns |false|. |
| // |
| // If |name| is NULL, deletes the default storage record, like what |
| // would have been deleted with the previous version of SbStorageDeleteRecord. |
| // |
| // This function must not be called while the storage record is open. |
| // This function performs blocking I/O on the calling thread. |
| // |
| // |name|: The filesystem-safe name of the record to open. |
| SB_EXPORT bool SbStorageDeleteRecord(const char* name); |
| #endif // SB_API_VERSION < 16 |
| |
| #ifdef __cplusplus |
| } // extern "C" |
| #endif |
| |
| #endif // STARBOARD_STORAGE_H_ |
