lbcd/mempoolerror.go

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// Copyright (c) 2014 The btcsuite developers
// Use of this source code is governed by an ISC
// license that can be found in the LICENSE file.
package main
import (
"github.com/btcsuite/btcd/blockchain"
"github.com/btcsuite/btcd/wire"
)
// RuleError identifies a rule violation. It is used to indicate that
// processing of a transaction failed due to one of the many validation
// rules. The caller can use type assertions to determine if a failure was
// specifically due to a rule violation and use the Err field to access the
// underlying error, which will be either a TxRuleError or a
// blockchain.RuleError.
type RuleError struct {
Err error
}
// Error satisfies the error interface and prints human-readable errors.
func (e RuleError) Error() string {
if e.Err == nil {
return "<nil>"
}
return e.Err.Error()
}
// TxRuleError identifies a rule violation. It is used to indicate that
// processing of a transaction failed due to one of the many validation
// rules. The caller can use type assertions to determine if a failure was
// specifically due to a rule violation and access the ErrorCode field to
// ascertain the specific reason for the rule violation.
type TxRuleError struct {
RejectCode wire.RejectCode // The code to send with reject messages
Description string // Human readable description of the issue
}
// Error satisfies the error interface and prints human-readable errors.
func (e TxRuleError) Error() string {
return e.Description
}
// txRuleError creates an underlying TxRuleError with the given a set of
// arguments and returns a RuleError that encapsulates it.
func txRuleError(c wire.RejectCode, desc string) RuleError {
return RuleError{
Err: TxRuleError{RejectCode: c, Description: desc},
}
}
// chainRuleError returns a RuleError that encapsulates the given
// blockchain.RuleError.
func chainRuleError(chainErr blockchain.RuleError) RuleError {
return RuleError{
Err: chainErr,
}
}
// extractRejectCode attempts to return a relevant reject code for a given error
// by examining the error for known types. It will return true if a code
// was successfully extracted.
func extractRejectCode(err error) (wire.RejectCode, bool) {
// Pull the underlying error out of a RuleError.
if rerr, ok := err.(RuleError); ok {
err = rerr.Err
}
switch err := err.(type) {
case blockchain.RuleError:
// Convert the chain error to a reject code.
var code wire.RejectCode
switch err.ErrorCode {
// Rejected due to duplicate.
case blockchain.ErrDuplicateBlock:
fallthrough
case blockchain.ErrDoubleSpend:
code = wire.RejectDuplicate
// Rejected due to obsolete version.
case blockchain.ErrBlockVersionTooOld:
code = wire.RejectObsolete
// Rejected due to checkpoint.
case blockchain.ErrCheckpointTimeTooOld:
fallthrough
case blockchain.ErrDifficultyTooLow:
fallthrough
case blockchain.ErrBadCheckpoint:
fallthrough
case blockchain.ErrForkTooOld:
code = wire.RejectCheckpoint
// Everything else is due to the block or transaction being invalid.
default:
code = wire.RejectInvalid
}
return code, true
case TxRuleError:
return err.RejectCode, true
case nil:
return wire.RejectInvalid, false
}
return wire.RejectInvalid, false
}
// errToRejectErr examines the underlying type of the error and returns a reject
// code and string appropriate to be sent in a wire.MsgReject message.
func errToRejectErr(err error) (wire.RejectCode, string) {
// Return the reject code along with the error text if it can be
// extracted from the error.
rejectCode, found := extractRejectCode(err)
if found {
return rejectCode, err.Error()
}
// Return a generic rejected string if there is no error. This really
// should not happen unless the code elsewhere is not setting an error
// as it should be, but it's best to be safe and simply return a generic
// string rather than allowing the following code that derferences the
// err to panic.
if err == nil {
return wire.RejectInvalid, "rejected"
}
// When the underlying error is not one of the above cases, just return
// wire.RejectInvalid with a generic rejected string plus the error
// text.
return wire.RejectInvalid, "rejected: " + err.Error()
}