SYNOPSIS
or #ethereumjs on freenode
![js-standard-style](https://cdn.rawgit.com/feross/standard/master/badge.svg)
Implements Ethereum's VM in Javascript.
Fork Support
The VM (v2.6.x
release series) currently supports the following hardforks
(default: Byzantium
):
Byzantium
Constantinople
Petersburg
Parallel HF support was introduced in the v2.5.0
release, if you want
some background have a look at the respective
release notes.
If you are still looking for a Spurious Dragon compatible version of this library install the latest of the 2.2.x
series (see Changelog).
INSTALL
npm install ethereumjs-vm
USAGE
var VM = require('ethereumjs-vm')
var vm = new VM()
var code = '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'
vm.runCode({
code: Buffer.from(code, 'hex'),
gasLimit: Buffer.from('ffffffff', 'hex')
}, function(err, results){
console.log('returned: ' + results.return.toString('hex'));
})
Also more examples can be found here
BROWSER
To build for standalone use in the browser, install browserify
and check run-transactions-simple example. This will give you a global variable EthVM
to use. The generated file will be at ./examples/run-transactions-simple/build.js
.
API
VM
For documentation on VM
instantiation, exposed API and emitted events
see generated API docs.
StateManger
The API for the StateManager
is currently in Beta
, separate documentation can be found here.
The StateManager
API has been largely reworked recently and the StateManager
will be removed from the VM and provided as a separate package in a future v3.0.0
release, see release notes for the v2.5.0
VM release for further details.
Internal Structure
The VM processes state changes at many levels.
- runBlockchain
- for every block, runBlock
- runBlock
- for every tx, runTx
- pay miner and uncles
- runTx
- check sender balance
- check sender nonce
- runCall
- transfer gas charges
- runCall
- checkpoint state
- transfer value
- load code
- runCode
- materialize created contracts
- revert or commit checkpoint
- runCode
- iterate over code
- run op codes
- track gas usage
- OpFns
- run individual op code
- modify stack
- modify memory
- calculate fee
The opFns for CREATE
, CALL
, and CALLCODE
call back up to runCall
.
DEVELOPMENT
Developer documentation - currently mainly with information on testing and debugging - can be found here.
LICENSE
MPL-2.0