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/*
* Copyright (C) 2016 The Android Open Source Project
*
* 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.
*/
#include <nvram/core/storage.h>
namespace nvram {
namespace storage {
namespace {
// Maximum number of space blobs supported.
const int kMaxSpaces = 32;
class StorageSlot {
public:
bool present() const { return blob_.size() != 0; }
Status Load(Blob* blob) const {
if (blob_.size() == 0) {
return Status::kNotFound;
}
if (!blob->Assign(blob_.data(), blob_.size())) {
return Status::kStorageError;
}
return Status::kSuccess;
}
Status Store(const Blob& blob) {
if (!blob_.Assign(blob.data(), blob.size())) {
return Status::kStorageError;
}
return Status::kSuccess;
}
Status Delete() {
return blob_.Resize(0) ? Status::kSuccess : Status::kStorageError;
}
private:
Blob blob_;
};
// Stores the header blob.
StorageSlot g_header;
// Stores the space blobs.
struct {
uint32_t index;
StorageSlot slot;
} g_spaces[kMaxSpaces];
// Find the storage slot in |g_spaces| that corresponds to |index|. Returns
// |nullptr| if no matching slot exists.
StorageSlot* FindSpaceSlot(uint32_t index) {
for (size_t i = 0; i < kMaxSpaces; ++i) {
if (g_spaces[i].slot.present() && g_spaces[i].index == index) {
return &g_spaces[i].slot;
}
}
return nullptr;
}
} // namespace
Status LoadHeader(Blob* blob) {
return g_header.Load(blob);
}
Status StoreHeader(const Blob& blob) {
return g_header.Store(blob);
}
Status LoadSpace(uint32_t index, Blob* blob) {
StorageSlot* slot = FindSpaceSlot(index);
return slot ? slot->Load(blob) : Status::kNotFound;
}
Status StoreSpace(uint32_t index, const Blob& blob) {
StorageSlot* slot = FindSpaceSlot(index);
if (slot) {
return slot->Store(blob);
}
// Allocate a new slot.
for (size_t i = 0; i < kMaxSpaces; ++i) {
if (!g_spaces[i].slot.present()) {
g_spaces[i].index = index;
return g_spaces[i].slot.Store(blob);
}
}
return Status::kStorageError;
}
Status DeleteSpace(uint32_t index) {
StorageSlot* slot = FindSpaceSlot(index);
if (slot) {
slot->Delete();
}
return Status::kSuccess;
}
} // namespace storage
} // namespace nvram