Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2022 Project CHIP Authors
       4              :  *
       5              :  *    Licensed under the Apache License, Version 2.0 (the "License");
       6              :  *    you may not use this file except in compliance with the License.
       7              :  *    You may obtain a copy of the License at
       8              :  *
       9              :  *        http://www.apache.org/licenses/LICENSE-2.0
      10              :  *
      11              :  *    Unless required by applicable law or agreed to in writing, software
      12              :  *    distributed under the License is distributed on an "AS IS" BASIS,
      13              :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14              :  *    See the License for the specific language governing permissions and
      15              :  *    limitations under the License.
      16              :  */
      17              : 
      18              : #pragma once
      19              : 
      20              : #include <cstdint>
      21              : 
      22              : #include <lib/core/CHIPError.h>
      23              : #include <lib/core/CHIPPersistentStorageDelegate.h>
      24              : #include <lib/support/CodeUtils.h>
      25              : #include <lib/support/SafeInt.h>
      26              : #include <platform/KeyValueStoreManager.h>
      27              : 
      28              : namespace chip {
      29              : 
      30              : // Sample version of PersistentStorageDelegate that relies only on a KeyValueStoreManager
      31              : class KvsPersistentStorageDelegate : public PersistentStorageDelegate
      32              : {
      33              : public:
      34              :     KvsPersistentStorageDelegate()          = default;
      35            1 :     virtual ~KvsPersistentStorageDelegate() = default;
      36              : 
      37              :     // No copy, move or assignment.
      38              :     KvsPersistentStorageDelegate(const KvsPersistentStorageDelegate &)             = delete;
      39              :     KvsPersistentStorageDelegate(const KvsPersistentStorageDelegate &&)            = delete;
      40              :     KvsPersistentStorageDelegate & operator=(const KvsPersistentStorageDelegate &) = delete;
      41              : 
      42              :     CHIP_ERROR Init(DeviceLayer::PersistedStorage::KeyValueStoreManager * kvsManager)
      43              :     {
      44              :         if (kvsManager == nullptr)
      45              :         {
      46              :             return CHIP_ERROR_INVALID_ARGUMENT;
      47              :         }
      48              :         mKvsManager = kvsManager;
      49              : 
      50              :         return CHIP_NO_ERROR;
      51              :     }
      52              : 
      53           55 :     CHIP_ERROR SyncGetKeyValue(const char * key, void * buffer, uint16_t & size) override
      54              :     {
      55           55 :         VerifyOrReturnError(mKvsManager != nullptr, CHIP_ERROR_INCORRECT_STATE);
      56              : 
      57           55 :         uint8_t emptyPlaceholder = 0;
      58           55 :         if (buffer == nullptr)
      59              :         {
      60            0 :             if (size != 0)
      61              :             {
      62            0 :                 return CHIP_ERROR_INVALID_ARGUMENT;
      63              :             }
      64              : 
      65              :             // When size is zero, let's give a non-nullptr to the KVS backend
      66            0 :             buffer = &emptyPlaceholder;
      67              :         }
      68              : 
      69           55 :         size_t bytesRead = 0;
      70           55 :         CHIP_ERROR err   = mKvsManager->Get(key, buffer, size, &bytesRead);
      71              : 
      72              :         // Update size only if it made sense
      73           55 :         if ((CHIP_ERROR_BUFFER_TOO_SMALL == err) || (CHIP_NO_ERROR == err))
      74              :         {
      75            0 :             size = CanCastTo<uint16_t>(bytesRead) ? static_cast<uint16_t>(bytesRead) : 0;
      76              :         }
      77              : 
      78           55 :         return err;
      79              :     }
      80              : 
      81            5 :     CHIP_ERROR SyncSetKeyValue(const char * key, const void * value, uint16_t size) override
      82              :     {
      83            5 :         VerifyOrReturnError(mKvsManager != nullptr, CHIP_ERROR_INCORRECT_STATE);
      84              : 
      85            5 :         uint8_t placeholderForEmpty = 0;
      86            5 :         if (value == nullptr)
      87              :         {
      88            0 :             if (size == 0)
      89              :             {
      90            0 :                 value = &placeholderForEmpty;
      91              :             }
      92              :             else
      93              :             {
      94            0 :                 return CHIP_ERROR_INVALID_ARGUMENT;
      95              :             }
      96              :         }
      97            5 :         return mKvsManager->Put(key, value, size);
      98              :     }
      99              : 
     100            0 :     CHIP_ERROR SyncDeleteKeyValue(const char * key) override
     101              :     {
     102            0 :         VerifyOrReturnError(mKvsManager != nullptr, CHIP_ERROR_INCORRECT_STATE);
     103            0 :         return mKvsManager->Delete(key);
     104              :     }
     105              : 
     106              : protected:
     107              :     DeviceLayer::PersistedStorage::KeyValueStoreManager * mKvsManager = nullptr;
     108              : };
     109              : 
     110              : } // namespace chip