Method storeLeaf

source/core/StarBTreeDatabase.cpp:742–806

}

auto BTreeDatabase::BTreeImpl::storeLeaf(Leaf leaf) -> Pointer {
  if (leaf->self != InvalidBlockIndex) {
    List<BlockIndex> tailBlocks = parent->leafTailBlocks(leaf->self);
    for (uint32_t i = 0; i < tailBlocks.size(); ++i)
      parent->freeBlock(tailBlocks[i]);

    if (!parent->m_uncommitted.contains(leaf->self)) {
      parent->freeBlock(leaf->self);
      leaf->self = InvalidBlockIndex;
    }
  }

  if (leaf->self == InvalidBlockIndex)
    leaf->self = parent->reserveBlock();

  BlockIndex currentLeafBlock = leaf->self;
  DataStreamBuffer leafBuffer;
  leafBuffer.reset(parent->m_blockSize);
  leafBuffer.writeData(LeafMagic, 2);

  DataStreamFunctions leafOutput({}, [&](char const* data, size_t len) -> size_t {
      size_t pos = 0;
      size_t left = len;

      while (true) {
        size_t toWrite = left;
        if (toWrite > parent->m_blockSize - leafBuffer.pos() - sizeof(BlockIndex))
          toWrite = parent->m_blockSize - leafBuffer.pos() - sizeof(BlockIndex);

        if (toWrite != 0) {
          leafBuffer.writeData(data + pos, toWrite);
          left -= toWrite;
          pos += toWrite;
        }

        if (left == 0)
          break;

        if (leafBuffer.pos() == (parent->m_blockSize - sizeof(BlockIndex))) {
          BlockIndex nextBlock = parent->reserveBlock();
          leafBuffer.write<BlockIndex>(nextBlock);
          parent->updateBlock(currentLeafBlock, leafBuffer.data());
          currentLeafBlock = nextBlock;
          leafBuffer.reset(parent->m_blockSize);
          leafBuffer.writeData(LeafMagic, 2);
        }
      }

      return len;
    });

  leafOutput.write<uint32_t>(leaf->elements.size());

  for (LeafNode::ElementList::iterator i = leaf->elements.begin(); i != leaf->elements.end(); ++i) {
    starAssert(i->key.size() == parent->m_keySize);
    leafOutput.writeBytes(i->key);
    leafOutput.write(i->data);
  }