Exemplo n.º 1
0
// DirBlockLocatorFromHash returns a block locator for the passed block hash.
// See BlockLocator for details on the algotirhm used to create a block locator.
//
// In addition to the general algorithm referenced above, there are a couple of
// special cases which are handled:
//
//  - If the genesis hash is passed, there are no previous hashes to add and
//    therefore the block locator will only consist of the genesis hash
//  - If the passed hash is not currently known, the block locator will only
//    consist of the passed hash
func DirBlockLocatorFromHash(hash *wire.ShaHash) blockchain.BlockLocator {
	// The locator contains the requested hash at the very least.
	locator := make(blockchain.BlockLocator, 0, wire.MaxBlockLocatorsPerMsg)
	locator = append(locator, hash)

	h, _ := common.HexToHash(common.GENESIS_DIR_BLOCK_HASH)
	genesisHash := wire.FactomHashToShaHash(h)
	// Nothing more to do if a locator for the genesis hash was requested.
	if genesisHash.IsEqual(hash) {
		return locator
	}

	// Attempt to find the height of the block that corresponds to the
	// passed hash, and if it's on a side chain, also find the height at
	// which it forks from the main chain.
	blockHeight := int64(-1)

	// Generate the block locators according to the algorithm described in
	// in the BlockLocator comment and make sure to leave room for the
	// final genesis hash.

	dblock, _ := db.FetchDBlockByHash(hash.ToFactomHash())
	if dblock != nil {
		blockHeight = int64(dblock.Header.DBHeight)
	}
	increment := int64(1)
	for len(locator) < wire.MaxBlockLocatorsPerMsg-1 {
		// Once there are 10 locators, exponentially increase the
		// distance between each block locator.
		if len(locator) > 10 {
			increment *= 2
		}
		blockHeight -= increment
		if blockHeight < 1 {
			break
		}

		blk, _ := db.FetchDBlockByHeight(uint32(blockHeight))
		if blk == nil {
			continue
		} else if blk.DBHash == nil {
			blk.DBHash, _ = common.CreateHash(blk)
		}

		locator = append(locator, wire.FactomHashToShaHash(blk.DBHash))
	}

	// Append the appropriate genesis block.
	locator = append(locator, genesisHash)
	return locator
}
Exemplo n.º 2
0
// FetchHeightRange looks up a range of blocks by the start and ending
// heights.  Fetch is inclusive of the start height and exclusive of the
// ending height. To fetch all hashes from the start height until no
// more are present, use the special id `AllShas'.
func (db *LevelDb) FetchHeightRange(startHeight, endHeight int64) (rshalist []wire.ShaHash, err error) {

	var endidx int64
	if endHeight == database.AllShas {
		endidx = startHeight + wire.MaxBlocksPerMsg
	} else {
		endidx = endHeight
	}

	shalist := make([]wire.ShaHash, 0, endidx-startHeight)
	for height := startHeight; height < endidx; height++ {
		// TODO(drahn) fix blkFile from height

		dbhash, lerr := db.FetchDBHashByHeight(uint32(height))
		if lerr != nil || dbhash == nil {
			break
		}

		sha := wire.FactomHashToShaHash(dbhash)
		shalist = append(shalist, *sha)
	}

	if err != nil {
		return
	}
	//log.Tracef("FetchIdxRange idx %v %v returned %v shas err %v", startHeight, endHeight, len(shalist), err)

	return shalist, nil
}
Exemplo n.º 3
0
// handleECBlockMsg is invoked when a peer receives a entry credit block
// message.
func (p *peer) handleECBlockMsg(msg *wire.MsgECBlock, buf []byte) {
	headerHash, err := msg.ECBlock.HeaderHash()
	if err != nil {
		panic(err)
	}
	hash := wire.FactomHashToShaHash(headerHash)

	iv := wire.NewInvVect(wire.InvTypeFactomEntryCreditBlock, hash)
	p.AddKnownInventory(iv)

	inMsgQueue <- msg
}