Atmosphere/libraries/libstratosphere/include/stratosphere/fs/fs_istorage.hpp

/*
 * Copyright (c) 2018-2020 Atmosphère-NX
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#pragma once
#include "fs_common.hpp"
#include "fs_file.hpp"
#include "fs_operate_range.hpp"

namespace ams::fs {

    class IStorage {
        public:
            virtual ~IStorage() { /* ... */ }

            virtual Result Read(s64 offset, void *buffer, size_t size) = 0;

            virtual Result Write(s64 offset, const void *buffer, size_t size) {
                return fs::ResultUnsupportedOperation();
            }

            virtual Result Flush() = 0;

            virtual Result SetSize(s64 size) {
                return fs::ResultUnsupportedOperation();
            }

            virtual Result GetSize(s64 *out) = 0;

            virtual Result OperateRange(void *dst, size_t dst_size, OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) {
                return fs::ResultUnsupportedOperation();
            }

            virtual Result OperateRange(OperationId op_id, s64 offset, s64 size) {
                return this->OperateRange(nullptr, 0, op_id, offset, size, nullptr, 0);
            }
        public:
            static inline bool IsRangeValid(s64 offset, s64 size, s64 total_size) {
                return offset >= 0 &&
                       size >= 0 &&
                       size <= total_size &&
                       offset <= (total_size - size);
            }

            static inline bool IsRangeValid(s64 offset, size_t size, s64 total_size) {
                return IsRangeValid(offset, static_cast<s64>(size), total_size);
            }

            static inline bool IsOffsetAndSizeValid(s64 offset, s64 size) {
                return offset >= 0 &&
                       size >= 0 &&
                       offset <= (offset + size);
            }

            static inline bool IsOffsetAndSizeValid(s64 offset, size_t size) {
                return IsOffsetAndSizeValid(offset, static_cast<s64>(size));
            }
    };

    class ReadOnlyStorageAdapter : public IStorage {
        private:
            std::shared_ptr<IStorage> shared_storage;
            std::unique_ptr<IStorage> unique_storage;
            IStorage *storage;
        public:
            ReadOnlyStorageAdapter(IStorage *s) : unique_storage(s) {
                this->storage = this->unique_storage.get();
            }
            ReadOnlyStorageAdapter(std::shared_ptr<IStorage> s) : shared_storage(s) {
                this->storage = this->shared_storage.get();
            }
            ReadOnlyStorageAdapter(std::unique_ptr<IStorage> s) : unique_storage(std::move(s)) {
                this->storage = this->unique_storage.get();
            }

            virtual ~ReadOnlyStorageAdapter() { /* ... */ }
        public:
            virtual Result Read(s64 offset, void *buffer, size_t size) {
                return this->storage->Read(offset, buffer, size);
            }

            virtual Result Flush() {
                return this->storage->Flush();
            }

            virtual Result GetSize(s64 *out) {
                return this->storage->GetSize(out);
            }

            virtual Result OperateRange(void *dst, size_t dst_size, OperationId op_id, s64 offset, s64 size, const void *src, size_t src_size) override {
                return this->storage->OperateRange(dst, dst_size, op_id, offset, size, src, src_size);
            }
    };

}