txhelpers.go

// txhelpers.go contains helper functions for working with transactions and
// blocks (e.g. checking for a transaction in a block).

package main

import (
	"sort"

	"github.com/decred/dcrd/chaincfg/chainhash"
	"github.com/decred/dcrd/dcrutil"
	"github.com/decred/dcrd/rpcclient"
	"github.com/decred/dcrd/txscript"
	"github.com/decred/dcrd/wire"
)

// TxAction is what is happening to the transaction (mined or inserted into
// mempool).
type TxAction int32

// Valid values for TxAction
const (
	TxMined TxAction = 1 << iota
	TxInserted
	// removed? invalidated?
)

func TxhashInSlice(txs []*dcrutil.Tx, txHash *chainhash.Hash) *dcrutil.Tx {
	if len(txs) < 1 {
		return nil
	}

	for _, minedTx := range txs {
		txSha := minedTx.Hash()
		if txHash.IsEqual(txSha) {
			return minedTx
		}
	}
	return nil
}

// includesStakeTx checks if a block contains a stake transaction hash
func IncludesStakeTx(txHash *chainhash.Hash, block *dcrutil.Block) (int, int8) {
	blockTxs := block.STransactions()

	if tx := TxhashInSlice(blockTxs, txHash); tx != nil {
		return tx.Index(), tx.Tree()
	}
	return -1, -1
}

// includesTx checks if a block contains a transaction hash
func IncludesTx(txHash *chainhash.Hash, block *dcrutil.Block) (int, int8) {
	blockTxs := block.Transactions()

	if tx := TxhashInSlice(blockTxs, txHash); tx != nil {
		return tx.Index(), tx.Tree()
	}
	return -1, -1
}

func blockConsumesOutpointWithAddresses(block *dcrutil.Block, addrs map[string]TxAction,
	c *rpcclient.Client) map[string][]*dcrutil.Tx {
	addrMap := make(map[string][]*dcrutil.Tx)

	checkForOutpointAddr := func(blockTxs []*dcrutil.Tx) {
		for _, tx := range blockTxs {
			for _, txIn := range tx.MsgTx().TxIn {
				prevOut := &txIn.PreviousOutPoint
				// For each TxIn, check the indicated vout index in the txid of the
				// previous outpoint.
				// txrr, err := c.GetRawTransactionVerbose(&prevOut.Hash)
				prevTx, err := c.GetRawTransaction(&prevOut.Hash)
				if err != nil {
					log.Debug("Unable to get raw transaction for ", prevOut.Hash.String())
					continue
				}

				// prevOut.Index should tell us which one, but check all anyway
				for _, txOut := range prevTx.MsgTx().TxOut {
					_, txAddrs, _, err := txscript.ExtractPkScriptAddrs(
						txOut.Version, txOut.PkScript, activeChain)
					if err != nil {
						log.Infof("ExtractPkScriptAddrs: %v", err.Error())
						continue
					}

					for _, txAddr := range txAddrs {
						addrstr := txAddr.EncodeAddress()
						if _, ok := addrs[addrstr]; ok {
							if addrMap[addrstr] == nil {
								addrMap[addrstr] = make([]*dcrutil.Tx, 0)
							}
							addrMap[addrstr] = append(addrMap[addrstr], prevTx)
						}
					}
				}
			}
		}
	}

	checkForOutpointAddr(block.Transactions())
	checkForOutpointAddr(block.STransactions())

	return addrMap
}

// BlockReceivesToAddresses checks a block for transactions paying to the
// specified addresses, and creates a map of addresses to a slice of dcrutil.Tx
// involving the address.
func BlockReceivesToAddresses(block *wire.MsgBlock, addrs map[string]TxAction) map[string][]*wire.MsgTx {
	addrMap := make(map[string][]*wire.MsgTx)

	checkForAddrOut := func(blockTxs []*wire.MsgTx) {
		for _, tx := range blockTxs {
			// Check the addresses associated with the PkScript of each TxOut
			for _, txOut := range tx.TxOut {
				_, txOutAddrs, _, err := txscript.ExtractPkScriptAddrs(txOut.Version,
					txOut.PkScript, activeChain)
				if err != nil {
					log.Infof("ExtractPkScriptAddrs: %v", err.Error())
					continue
				}

				// Check if we are watching any address for this TxOut
				for _, txAddr := range txOutAddrs {
					addrstr := txAddr.EncodeAddress()
					if _, ok := addrs[addrstr]; ok {
						if _, gotSlice := addrMap[addrstr]; !gotSlice {
							addrMap[addrstr] = make([]*wire.MsgTx, 0) // nil
						}
						addrMap[addrstr] = append(addrMap[addrstr], tx)
					}
				}
			}
		}
	}

	checkForAddrOut(block.Transactions)
	checkForAddrOut(block.STransactions)

	return addrMap
}

// MedianAmount gets the median Amount from a slice of Amounts
func MedianAmount(s []dcrutil.Amount) dcrutil.Amount {
	if len(s) == 0 {
		return 0
	}

	sort.Sort(dcrutil.AmountSorter(s))

	middle := len(s) / 2

	if len(s) == 0 {
		return 0
	} else if (len(s) % 2) != 0 {
		return s[middle]
	}
	return (s[middle] + s[middle-1]) / 2
}

// MedianCoin gets the median DCR from a slice of float64s
func MedianCoin(s []float64) float64 {
	if len(s) == 0 {
		return 0
	}

	sort.Float64s(s)

	middle := len(s) / 2

	if len(s) == 0 {
		return 0
	} else if (len(s) % 2) != 0 {
		return s[middle]
	}
	return (s[middle] + s[middle-1]) / 2
}