The design stipulates that any get/set methods accessing disk blocks must call BlockBuffer::getBufferPtr() which calls getBlock(). So, not calling getBlock() in the constructor simply delays copying the block into the buffer until it is actually needed i.e to access the blocks data.
The design stipulates that any get/set methods accessing disk blocks must call BlockBuffer::getBufferPtr() which calls getBlock(). So, not calling getBlock() in the constructor simply delays copying the block into the buffer until it is actually needed i.e to access the blocks data.