Plugin system

gistfile1.cpp

/// Current plug-ing system, schematically:

std::vector<Block*> BlockCB; // Dirt, Stone, Stairs, Torch, ...

PacketHandler::player_does_something()
{
  int16_t block_type = figureOutAffectedBlockType();

  for ( each Block* blockcb in BlockCB)
  {
    if (blockcb != NULL &&  blockcb->affectedBlock(block_type))
    {
      blockcb->onRelevantEvent();
      // ...
    }
  }

  // repeated many times
}

/***********************/

/// Observation: affectedBlock() ONLY returns "true" for at most 2 blocks: The actual affected block, and the default block. Yet each time the entire BlockCB vector has to be traversed. Here's how this could be accelerated:

clever_map_type<int8_t, Block*> BLOCK_ACTIONS;

PacketHandler::player_does_something()
{
  int16_t block_type = figureOutAffectedBlockType();
  if (BLOCK_ACTIONS[block_type])
  {
    BLOCK_ACTIONS[block_type]->onRelevantEvent();
  }
  BLOCK_ACTIONS["default"]->onRelevantEvent();
}

/// The assumption is that the default handler is called AFTER the specific one. One could split this up into PRE and POST default actions if desired.

/// Even better, wrap it up (requires modification of the inherited classes):

struct BlockHelper
{
  static Block * get(int16_t block_type)
  {
    iterator it = BLOCK_ACTIONS.find(block_type);
    if (it == BLOCK_ACTIONS.end()) return BLOCK_ACTIONS["default"];
    return it->second;
  }
private:
  static clever_map_type<int8_t, Block*> BLOCK_ACTIONS;
};

/* We must modify the derived classes to call the default action: */
class BlockStairs : public BlockBasic
{
  // ...

  void onPlace(args...)
  {
    // ...
    BlockBasic::onPlace(args...);
  }

  // ...
};