| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef PPAPI_SHARED_IMPL_FILE_IO_STATE_MANAGER_H_ |
| #define PPAPI_SHARED_IMPL_FILE_IO_STATE_MANAGER_H_ |
| |
| #include "base/basictypes.h" |
| #include "base/compiler_specific.h" |
| #include "ppapi/c/pp_stdint.h" |
| #include "ppapi/shared_impl/ppapi_shared_export.h" |
| |
| namespace ppapi { |
| |
| // FileIOStateManager is a helper class that maintains the state of operations. |
| // For example, some operations are mutually exclusive, meaning that an |
| // operation could be rejected because of the current pending operation. Also, |
| // most of the operations only work when the file has been opened. |
| class PPAPI_SHARED_EXPORT FileIOStateManager { |
| public: |
| FileIOStateManager(); |
| ~FileIOStateManager(); |
| |
| enum OperationType { |
| // There is no pending operation right now. |
| OPERATION_NONE, |
| |
| // If there are pending reads, any other kind of async operation is not |
| // allowed. |
| OPERATION_READ, |
| |
| // If there are pending writes, any other kind of async operation is not |
| // allowed. |
| OPERATION_WRITE, |
| |
| // If there is a pending operation that is neither read nor write, no |
| // further async operation is allowed. |
| OPERATION_EXCLUSIVE |
| }; |
| |
| OperationType get_pending_operation() const { return pending_op_; } |
| |
| void SetOpenSucceed(); |
| |
| // Called at the beginning of each operation. It is responsible to make sure |
| // that state is correct. For example, some operations are only valid after |
| // the file is opened, or operations might need to run exclusively. |
| // |
| // It returns |PP_OK| on success, or |PP_ERROR_...| for various reasons. |
| int32_t CheckOperationState(OperationType new_op, bool should_be_open); |
| |
| // Marks the state of current operations as started or finished. |
| void SetPendingOperation(OperationType op); |
| void SetOperationFinished(); |
| |
| private: |
| int num_pending_ops_; |
| OperationType pending_op_; |
| |
| // Set to true when the file has been successfully opened. |
| bool file_open_; |
| |
| DISALLOW_COPY_AND_ASSIGN(FileIOStateManager); |
| }; |
| |
| } // namespace ppapi |
| |
| #endif // PPAPI_SHARED_IMPL_FILE_IO_STATE_MANAGER_H_ |
| |