fdc2bc867b
This converts the majority of script errors from generic errors created via errors.New and fmt.Errorf to use a concrete type that implements the error interface with an error code and description. This allows callers to programmatically detect the type of error via type assertions and an error code while still allowing the errors to provide more context. For example, instead of just having an error the reads "disabled opcode" as would happen prior to these changes when a disabled opcode is encountered, the error will now read "attempt to execute disabled opcode OP_FOO". While it was previously possible to programmatically detect many errors due to them being exported, they provided no additional context and there were also various instances that were just returning errors created on the spot which callers could not reliably detect without resorting to looking at the actual error message, which is nearly always bad practice. Also, while here, export the MaxStackSize and MaxScriptSize constants since they can be useful for consumers of the package and perform some minor cleanup of some of the tests.
43 lines
1.9 KiB
Go
43 lines
1.9 KiB
Go
// Copyright (c) 2013-2017 The btcsuite developers
|
|
// Use of this source code is governed by an ISC
|
|
// license that can be found in the LICENSE file.
|
|
|
|
/*
|
|
Package txscript implements the bitcoin transaction script language.
|
|
|
|
A complete description of the script language used by bitcoin can be found at
|
|
https://en.bitcoin.it/wiki/Script. The following only serves as a quick
|
|
overview to provide information on how to use the package.
|
|
|
|
This package provides data structures and functions to parse and execute
|
|
bitcoin transaction scripts.
|
|
|
|
Script Overview
|
|
|
|
Bitcoin transaction scripts are written in a stack-base, FORTH-like language.
|
|
|
|
The bitcoin script language consists of a number of opcodes which fall into
|
|
several categories such pushing and popping data to and from the stack,
|
|
performing basic and bitwise arithmetic, conditional branching, comparing
|
|
hashes, and checking cryptographic signatures. Scripts are processed from left
|
|
to right and intentionally do not provide loops.
|
|
|
|
The vast majority of Bitcoin scripts at the time of this writing are of several
|
|
standard forms which consist of a spender providing a public key and a signature
|
|
which proves the spender owns the associated private key. This information
|
|
is used to prove the the spender is authorized to perform the transaction.
|
|
|
|
One benefit of using a scripting language is added flexibility in specifying
|
|
what conditions must be met in order to spend bitcoins.
|
|
|
|
Errors
|
|
|
|
Errors returned by this package are of type txscript.Error. This allows the
|
|
caller to programmatically determine the specific error by examining the
|
|
ErrorCode field of the type asserted txscript.Error while still providing rich
|
|
error messages with contextual information. A convenience function named
|
|
IsErrorCode is also provided to allow callers to easily check for a specific
|
|
error code. See ErrorCode in the package documentation for a full list.
|
|
*/
|
|
package txscript
|