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// 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_
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