377 lines
14 KiB
Go
377 lines
14 KiB
Go
// Copyright (c) 2013-2017 The btcsuite developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package txscript
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import (
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"fmt"
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)
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// ErrorCode identifies a kind of script error.
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type ErrorCode int
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// These constants are used to identify a specific Error.
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const (
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// ErrInternal is returned if internal consistency checks fail. In
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// practice this error should never be seen as it would mean there is an
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// error in the engine logic.
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ErrInternal ErrorCode = iota
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// ---------------------------------------
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// Failures related to improper API usage.
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// ---------------------------------------
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// ErrInvalidFlags is returned when the passed flags to NewEngine
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// contain an invalid combination.
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ErrInvalidFlags
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// ErrInvalidIndex is returned when an out-of-bounds index is passed to
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// a function.
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ErrInvalidIndex
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// ErrUnsupportedAddress is returned when a concrete type that
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// implements a btcutil.Address is not a supported type.
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ErrUnsupportedAddress
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// ErrNotMultisigScript is returned from CalcMultiSigStats when the
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// provided script is not a multisig script.
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ErrNotMultisigScript
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// ErrTooManyRequiredSigs is returned from MultiSigScript when the
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// specified number of required signatures is larger than the number of
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// provided public keys.
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ErrTooManyRequiredSigs
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// ErrTooMuchNullData is returned from NullDataScript when the length of
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// the provided data exceeds MaxDataCarrierSize.
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ErrTooMuchNullData
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// ------------------------------------------
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// Failures related to final execution state.
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// ------------------------------------------
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// ErrEarlyReturn is returned when OP_RETURN is executed in the script.
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ErrEarlyReturn
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// ErrEmptyStack is returned when the script evaluated without error,
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// but terminated with an empty top stack element.
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ErrEmptyStack
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// ErrEvalFalse is returned when the script evaluated without error but
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// terminated with a false top stack element.
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ErrEvalFalse
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// ErrScriptUnfinished is returned when CheckErrorCondition is called on
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// a script that has not finished executing.
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ErrScriptUnfinished
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// ErrScriptDone is returned when an attempt to execute an opcode is
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// made once all of them have already been executed. This can happen
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// due to things such as a second call to Execute or calling Step after
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// all opcodes have already been executed.
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ErrInvalidProgramCounter
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// -----------------------------------------------------
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// Failures related to exceeding maximum allowed limits.
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// -----------------------------------------------------
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// ErrScriptTooBig is returned if a script is larger than MaxScriptSize.
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ErrScriptTooBig
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// ErrElementTooBig is returned if the size of an element to be pushed
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// to the stack is over MaxScriptElementSize.
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ErrElementTooBig
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// ErrTooManyOperations is returned if a script has more than
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// MaxOpsPerScript opcodes that do not push data.
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ErrTooManyOperations
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// ErrStackOverflow is returned when stack and altstack combined depth
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// is over the limit.
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ErrStackOverflow
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// ErrInvalidPubKeyCount is returned when the number of public keys
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// specified for a multsig is either negative or greater than
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// MaxPubKeysPerMultiSig.
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ErrInvalidPubKeyCount
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// ErrInvalidSignatureCount is returned when the number of signatures
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// specified for a multisig is either negative or greater than the
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// number of public keys.
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ErrInvalidSignatureCount
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// ErrNumberTooBig is returned when the argument for an opcode that
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// expects numeric input is larger than the expected maximum number of
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// bytes. For the most part, opcodes that deal with stack manipulation
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// via offsets, arithmetic, numeric comparison, and boolean logic are
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// those that this applies to. However, any opcode that expects numeric
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// input may fail with this code.
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ErrNumberTooBig
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// --------------------------------------------
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// Failures related to verification operations.
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// --------------------------------------------
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// ErrVerify is returned when OP_VERIFY is encountered in a script and
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// the top item on the data stack does not evaluate to true.
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ErrVerify
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// ErrEqualVerify is returned when OP_EQUALVERIFY is encountered in a
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// script and the top item on the data stack does not evaluate to true.
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ErrEqualVerify
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// ErrNumEqualVerify is returned when OP_NUMEQUALVERIFY is encountered
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// in a script and the top item on the data stack does not evaluate to
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// true.
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ErrNumEqualVerify
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// ErrCheckSigVerify is returned when OP_CHECKSIGVERIFY is encountered
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// in a script and the top item on the data stack does not evaluate to
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// true.
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ErrCheckSigVerify
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// ErrCheckSigVerify is returned when OP_CHECKMULTISIGVERIFY is
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// encountered in a script and the top item on the data stack does not
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// evaluate to true.
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ErrCheckMultiSigVerify
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// --------------------------------------------
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// Failures related to improper use of opcodes.
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// --------------------------------------------
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// ErrDisabledOpcode is returned when a disabled opcode is encountered
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// in a script.
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ErrDisabledOpcode
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// ErrReservedOpcode is returned when an opcode marked as reserved
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// is encountered in a script.
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ErrReservedOpcode
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// ErrMalformedPush is returned when a data push opcode tries to push
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// more bytes than are left in the script.
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ErrMalformedPush
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// ErrInvalidStackOperation is returned when a stack operation is
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// attempted with a number that is invalid for the current stack size.
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ErrInvalidStackOperation
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// ErrUnbalancedConditional is returned when an OP_ELSE or OP_ENDIF is
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// encountered in a script without first having an OP_IF or OP_NOTIF or
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// the end of script is reached without encountering an OP_ENDIF when
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// an OP_IF or OP_NOTIF was previously encountered.
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ErrUnbalancedConditional
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// ---------------------------------
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// Failures related to malleability.
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// ---------------------------------
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// ErrMinimalData is returned when the ScriptVerifyMinimalData flag
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// is set and the script contains push operations that do not use
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// the minimal opcode required.
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ErrMinimalData
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// ErrInvalidSigHashType is returned when a signature hash type is not
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// one of the supported types.
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ErrInvalidSigHashType
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// ErrSigDER is returned when a signature is not a canonically-encoded
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// DER signature.
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ErrSigDER
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// ErrSigHighS is returned when the ScriptVerifyLowS flag is set and the
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// script contains any signatures whose S values are higher than the
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// half order.
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ErrSigHighS
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// ErrNotPushOnly is returned when a script that is required to only
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// push data to the stack performs other operations. A couple of cases
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// where this applies is for a pay-to-script-hash signature script when
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// bip16 is active and when the ScriptVerifySigPushOnly flag is set.
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ErrNotPushOnly
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// ErrSigNullDummy is returned when the ScriptStrictMultiSig flag is set
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// and a multisig script has anything other than 0 for the extra dummy
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// argument.
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ErrSigNullDummy
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// ErrPubKeyType is returned when the ScriptVerifyStrictEncoding
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// flag is set and the script contains invalid public keys.
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ErrPubKeyType
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// ErrCleanStack is returned when the ScriptVerifyCleanStack flag
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// is set, and after evalution, the stack does not contain only a
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// single element.
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ErrCleanStack
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// ErrNullFail is returned when the ScriptVerifyNullFail flag is
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// set and signatures are not empty on failed checksig or checkmultisig
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// operations.
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ErrNullFail
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// ErrWitnessMalleated is returned if ScriptVerifyWitness is set and a
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// native p2wsh program is encountered which has a non-empty sigScript.
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ErrWitnessMalleated
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// ErrWitnessMalleatedP2SH is returned if ScriptVerifyWitness if set
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// and the validation logic for nested p2sh encounters a sigScript
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// which isn't *exactyl* a datapush of the witness program.
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ErrWitnessMalleatedP2SH
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// -------------------------------
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// Failures related to soft forks.
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// -------------------------------
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// ErrDiscourageUpgradableNOPs is returned when the
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// ScriptDiscourageUpgradableNops flag is set and a NOP opcode is
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// encountered in a script.
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ErrDiscourageUpgradableNOPs
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// ErrNegativeLockTime is returned when a script contains an opcode that
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// interprets a negative lock time.
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ErrNegativeLockTime
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// ErrUnsatisfiedLockTime is returned when a script contains an opcode
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// that involves a lock time and the required lock time has not been
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// reached.
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ErrUnsatisfiedLockTime
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// ErrMinimalIf is returned if ScriptVerifyWitness is set and the
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// operand of an OP_IF/OP_NOF_IF are not either an empty vector or
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// [0x01].
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ErrMinimalIf
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// ErrDiscourageUpgradableWitnessProgram is returned if
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// ScriptVerifyWitness is set and the versino of an executing witness
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// program is outside the set of currently defined witness program
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// vesions.
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ErrDiscourageUpgradableWitnessProgram
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// ----------------------------------------
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// Failures related to segregated witness.
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// ----------------------------------------
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// ErrWitnessProgramEmpty is returned if ScriptVerifyWitness is set and
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// the witness stack itself is empty.
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ErrWitnessProgramEmpty
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// ErrWitnessProgramMismatch is returned if ScriptVerifyWitness is set
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// and the witness itself for a p2wkh witness program isn't *exactly* 2
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// items or if the witness for a p2wsh isn't the sha255 of the witness
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// script.
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ErrWitnessProgramMismatch
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// ErrWitnessProgramWrongLength is returned if ScriptVerifyWitness is
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// set and the length of the witness program violates the length as
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// dictated by the current witness version.
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ErrWitnessProgramWrongLength
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// ErrWitnessUnexpected is returned if ScriptVerifyWitness is set and a
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// transaction includes witness data but doesn't spend an which is a
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// witness program (nested or native).
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ErrWitnessUnexpected
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// ErrWitnessPubKeyType is returned if ScriptVerifyWitness is set and
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// the public key used in either a check-sig or check-multi-sig isn't
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// serialized in a compressed format.
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ErrWitnessPubKeyType
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// numErrorCodes is the maximum error code number used in tests. This
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// entry MUST be the last entry in the enum.
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numErrorCodes
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)
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// Map of ErrorCode values back to their constant names for pretty printing.
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var errorCodeStrings = map[ErrorCode]string{
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ErrInternal: "ErrInternal",
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ErrInvalidFlags: "ErrInvalidFlags",
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ErrInvalidIndex: "ErrInvalidIndex",
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ErrUnsupportedAddress: "ErrUnsupportedAddress",
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ErrNotMultisigScript: "ErrNotMultisigScript",
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ErrTooManyRequiredSigs: "ErrTooManyRequiredSigs",
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ErrTooMuchNullData: "ErrTooMuchNullData",
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ErrEarlyReturn: "ErrEarlyReturn",
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ErrEmptyStack: "ErrEmptyStack",
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ErrEvalFalse: "ErrEvalFalse",
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ErrScriptUnfinished: "ErrScriptUnfinished",
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ErrInvalidProgramCounter: "ErrInvalidProgramCounter",
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ErrScriptTooBig: "ErrScriptTooBig",
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ErrElementTooBig: "ErrElementTooBig",
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ErrTooManyOperations: "ErrTooManyOperations",
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ErrStackOverflow: "ErrStackOverflow",
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ErrInvalidPubKeyCount: "ErrInvalidPubKeyCount",
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ErrInvalidSignatureCount: "ErrInvalidSignatureCount",
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ErrNumberTooBig: "ErrNumberTooBig",
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ErrVerify: "ErrVerify",
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ErrEqualVerify: "ErrEqualVerify",
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ErrNumEqualVerify: "ErrNumEqualVerify",
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ErrCheckSigVerify: "ErrCheckSigVerify",
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ErrCheckMultiSigVerify: "ErrCheckMultiSigVerify",
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ErrDisabledOpcode: "ErrDisabledOpcode",
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ErrReservedOpcode: "ErrReservedOpcode",
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ErrMalformedPush: "ErrMalformedPush",
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ErrInvalidStackOperation: "ErrInvalidStackOperation",
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ErrUnbalancedConditional: "ErrUnbalancedConditional",
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ErrMinimalData: "ErrMinimalData",
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ErrInvalidSigHashType: "ErrInvalidSigHashType",
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ErrSigDER: "ErrSigDER",
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ErrSigHighS: "ErrSigHighS",
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ErrNotPushOnly: "ErrNotPushOnly",
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ErrSigNullDummy: "ErrSigNullDummy",
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ErrPubKeyType: "ErrPubKeyType",
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ErrCleanStack: "ErrCleanStack",
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ErrNullFail: "ErrNullFail",
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ErrDiscourageUpgradableNOPs: "ErrDiscourageUpgradableNOPs",
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ErrNegativeLockTime: "ErrNegativeLockTime",
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ErrUnsatisfiedLockTime: "ErrUnsatisfiedLockTime",
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ErrWitnessProgramEmpty: "ErrWitnessProgramEmpty",
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ErrWitnessProgramMismatch: "ErrWitnessProgramMismatch",
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ErrWitnessProgramWrongLength: "ErrWitnessProgramWrongLength",
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ErrWitnessMalleated: "ErrWitnessMalleated",
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ErrWitnessMalleatedP2SH: "ErrWitnessMalleatedP2SH",
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ErrWitnessUnexpected: "ErrWitnessUnexpected",
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ErrMinimalIf: "ErrMinimalIf",
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ErrWitnessPubKeyType: "ErrWitnessPubKeyType",
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ErrDiscourageUpgradableWitnessProgram: "ErrDiscourageUpgradableWitnessProgram",
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}
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// String returns the ErrorCode as a human-readable name.
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func (e ErrorCode) String() string {
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if s := errorCodeStrings[e]; s != "" {
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return s
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}
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return fmt.Sprintf("Unknown ErrorCode (%d)", int(e))
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}
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// Error identifies a script-related error. It is used to indicate three
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// classes of errors:
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// 1) Script execution failures due to violating one of the many requirements
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// imposed by the script engine or evaluating to false
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// 2) Improper API usage by callers
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// 3) Internal consistency check failures
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//
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// The caller can use type assertions on the returned errors to access the
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// ErrorCode field to ascertain the specific reason for the error. As an
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// additional convenience, the caller may make use of the IsErrorCode function
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// to check for a specific error code.
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type Error struct {
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ErrorCode ErrorCode
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Description string
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}
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// Error satisfies the error interface and prints human-readable errors.
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func (e Error) Error() string {
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return e.Description
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}
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// scriptError creates an Error given a set of arguments.
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func scriptError(c ErrorCode, desc string) Error {
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return Error{ErrorCode: c, Description: desc}
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}
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// IsErrorCode returns whether or not the provided error is a script error with
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// the provided error code.
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func IsErrorCode(err error, c ErrorCode) bool {
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serr, ok := err.(Error)
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return ok && serr.ErrorCode == c
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}
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