Filesystem: Add IPFS implementation

This adds an abstraction for a data store. LMDB is included as an
implementation.

A block store is built on the data store abstraction. Blocks are chunks
data addressed by a CID (content identifier).

cmake/treedata/common/subdirs.txt

@@ -18,6 +18,7 @@ xbmc/crypto/did                                 crypto/did
 xbmc/crypto/ed25519                             crypto/ed25519
 xbmc/crypto/multiformats                        crypto/multiformats
 xbmc/crypto/random                              crypto/random
+xbmc/datastore                                  datastore
 xbmc/dbwrappers                                 dbwrappers
 xbmc/dialogs                                    dialogs
 xbmc/favourites                                 favourites

xbmc/datastore/Block.cpp

@@ -0,0 +1,30 @@
+/*
+ *  Copyright (C) 2018-2020 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#include "Block.h"
+
+using namespace KODI;
+using namespace DATASTORE;
+
+CBlock::CBlock(CCID cid, std::vector<uint8_t> data) : m_cid(std::move(cid)), m_data(std::move(data))
+{
+}
+
+std::vector<uint8_t> CBlock::Serialize() const
+{
+  std::vector<uint8_t> data;
+
+  //! @todo
+
+  return data;
+}
+
+void CBlock::Deserialize(const std::vector<uint8_t>& data)
+{
+  //! @todo
+}

xbmc/datastore/Block.h

@@ -0,0 +1,81 @@
+/*
+ *  Copyright (C) 2018-2020 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#pragma once
+
+#include "CID.h"
+
+#include <stdint.h>
+#include <utility>
+#include <vector>
+
+namespace KODI
+{
+namespace DATASTORE
+{
+/*!
+ * \brief Container of raw data with a CID identifier
+ */
+class CBlock
+{
+public:
+  /*!
+   * \brief Construct an empty block
+   */
+  CBlock() = default;
+
+  /*!
+   * \brief Construct a block from parameters
+   *
+   * \param cid The block CID
+   * \param data The block data
+   */
+  CBlock(CCID cid, std::vector<uint8_t> data);
+
+  /*!
+   * \brief Get the CID
+   */
+  const CCID& CID() const { return m_cid; }
+
+  /*!
+   * \brief Set the CID
+   */
+  void SetCID(CCID cid) { m_cid = std::move(cid); }
+
+  /*!
+   * \brief Get the data (const)
+   */
+  const std::vector<uint8_t>& Data() const { return m_data; }
+
+  /*!
+   * \brief Get the data (mutable)
+   */
+  std::vector<uint8_t>& Data() { return m_data; }
+
+  /*!
+   * \brief Set the data
+   */
+  void SetData(std::vector<uint8_t> data) { m_data = std::move(data); }
+
+  /*!
+   * \brief Serialize as an array of bytes
+   */
+  std::vector<uint8_t> Serialize() const;
+
+  /*!
+   * \brief Deserialize an array of bytes
+   */
+  void Deserialize(const std::vector<uint8_t>& data);
+
+private:
+  // Block parameters
+  CCID m_cid;
+  std::vector<uint8_t> m_data;
+};
+} // namespace DATASTORE
+} // namespace KODI

xbmc/datastore/BlockStore.cpp

@@ -0,0 +1,63 @@
+/*
+ *  Copyright (C) 2018-2020 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#include "BlockStore.h"
+
+#include "Block.h"
+#include "CID.h"
+#include "DataStore.h"
+
+using namespace KODI;
+using namespace DATASTORE;
+
+CBlockStore::CBlockStore(CDataStore& dataStore) : m_dataStore(dataStore)
+{
+}
+
+bool CBlockStore::Has(const CCID& cid)
+{
+  std::vector<uint8_t> key = cid.Serialize();
+
+  if (m_dataStore.Has(key.data(), key.size()))
+    return true;
+
+  return false;
+}
+
+bool CBlockStore::Get(const CCID& cid, CBlock& block)
+{
+  std::vector<uint8_t> key = cid.Serialize();
+
+  if (m_dataStore.Get(key.data(), key.size(), block.Data()))
+  {
+    block.SetCID(cid);
+    return true;
+  }
+
+  return false;
+}
+
+bool CBlockStore::Put(const CBlock& block)
+{
+  std::vector<uint8_t> key = block.CID().Serialize();
+
+  if (m_dataStore.Put(key.data(), key.size(), block.Data().data(), block.Data().size()))
+    return true;
+
+  return false;
+}
+
+bool CBlockStore::Delete(const CCID& cid)
+{
+  std::vector<uint8_t> key = cid.Serialize();
+
+  if (m_dataStore.Delete(key.data(), key.size()))
+    return true;
+
+  return false;
+}

xbmc/datastore/BlockStore.h

@@ -0,0 +1,76 @@
+/*
+ *  Copyright (C) 2018-2020 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#pragma once
+
+namespace KODI
+{
+namespace DATASTORE
+{
+class CBlock;
+class CCID;
+class CDataStore;
+
+/*!
+ * \brief Thin wrapper over a data store for getting and putting block
+ *        objects
+ */
+class CBlockStore
+{
+public:
+  /*!
+   * \brief Construct a block store
+   *
+   * \param dataStore The underlying data store
+   */
+  CBlockStore(CDataStore& dataStore);
+  ~CBlockStore() = default;
+
+  /*!
+   * \brief Determine if the CID can be found
+   *
+   * \param CID The CID to look for
+   *
+   * \return True if a block with the given CID was found, false otherwise
+   */
+  bool Has(const CCID& cid);
+
+  /*!
+   * \brief Find a block based on its CID
+   *
+   * \param cid The CID to look for
+   * \param block The block, or unmodified if this returns false
+   *
+   * \return True if the block was retrieved, false for missing CID or error
+   */
+  bool Get(const CCID& cid, CBlock& block);
+
+  /*!
+   * \brief Add a block to the block store, replacing any existing block
+   *
+   * \param block The block to store
+   *
+   * \return True if the block was added, false on error
+   */
+  bool Put(const CBlock& block);
+
+  /*!
+   * \brief Delete a block based on its CID
+   *
+   * \param CID The CID to look for
+   *
+   * \return True on success, false on error
+   */
+  bool Delete(const CCID& cid);
+
+private:
+  // Construction parameters
+  CDataStore& m_dataStore;
+};
+} // namespace DATASTORE
+} // namespace KODI

xbmc/datastore/CID.cpp

@@ -0,0 +1,31 @@
+/*
+ *  Copyright (C) 2018-2020 Team Kodi
+ *  This file is part of Kodi - https://kodi.tv
+ *
+ *  SPDX-License-Identifier: GPL-2.0-or-later
+ *  See LICENSES/README.md for more information.
+ */
+
+#include "CID.h"
+
+using namespace KODI;
+using namespace DATASTORE;
+
+CCID::CCID(CIDCodec codec, std::vector<uint8_t> multihash)
+  : m_codec(codec), m_multihash(std::move(multihash))
+{
+}
+
+std::vector<uint8_t> CCID::Serialize() const
+{
+  std::vector<uint8_t> data;
+
+  //! @todo
+
+  return data;
+}
+
+void CCID::Deserialize(const std::vector<uint8_t>& data)
+{
+  //! @todo
+}