func (a *BuyActivity) transmitWorkChunked(log bitwrk.Logger, client *http.Client) (io.ReadCloser, error) {
if r, err := a.requestMissingChunks(log.New("request missing chunks"), client); err != nil {
return nil, err
} else {
defer r.Close()
numChunks := a.workFile.NumChunks()
if numChunks > 16384 {
return nil, fmt.Errorf("Work file too big: %d chunks.", numChunks)
}
wishList := make([]byte, int(numChunks+7)/8)
if _, err := io.ReadFull(r, wishList); err != nil {
return nil, fmt.Errorf("Error decoding list of missing chunks: %v", err)
}
return a.sendMissingChunksAndReturnResult(log.New("send work chunk data"), client, wishList)
}
}
func (a *BuyActivity) doPerformBuy(log bitwrk.Logger, interrupt <-chan bool) (cafs.File, error) {
if err := a.beginTrade(log, interrupt); err != nil {
return nil, err
}
// draw random bytes for buyer's secret
var secret bitwrk.Thash
if _, err := rand.Reader.Read(secret[:]); err != nil {
return nil, err
}
a.buyerSecret = &secret
log.Printf("Computed buyer's secret.")
// Get work hash
var workHash, workSecretHash bitwrk.Thash
workHash = bitwrk.Thash(a.workFile.Key())
// compute workSecretHash = hash(workHash | secret)
hash := sha256.New()
hash.Write(workHash[:])
hash.Write(secret[:])
hash.Sum(workSecretHash[:0])
// Start polling for transaction state changes in background
abortPolling := make(chan bool)
defer func() {
abortPolling <- true // Stop polling when sell has ended
}()
go func() {
a.pollTransaction(log, abortPolling)
}()
if err := SendTxMessageEstablishBuyer(a.txId, a.identity, workHash, workSecretHash); err != nil {
return nil, fmt.Errorf("Error establishing buyer: %v", err)
}
if err := a.waitForTransactionPhase(log.New("establishing"), bitwrk.PhaseTransmitting, bitwrk.PhaseBuyerEstablished); err != nil {
return nil, fmt.Errorf("Error awaiting TRANSMITTING phase: %v", err)
}
if err := a.interactWithSeller(log.New("transmitting")); err != nil {
return nil, fmt.Errorf("Error transmitting work and receiving encrypted result: %v", err)
}
if err := a.waitForTransactionPhase(log, bitwrk.PhaseUnverified, bitwrk.PhaseTransmitting, bitwrk.PhaseWorking); err != nil {
return nil, fmt.Errorf("Error awaiting UNVERIFIED phase: %v", err)
}
a.encResultKey = a.tx.ResultDecryptionKey
if err := a.decryptResult(); err != nil {
return nil, fmt.Errorf("Error decrypting result: %v", err)
}
if err := SendTxMessageAcceptResult(a.txId, a.identity); err != nil {
return nil, fmt.Errorf("Failed to send 'accept result' message: %v", err)
}
a.waitWhile(func() bool { return a.tx.State == bitwrk.StateActive })
return a.resultFile, nil
}