Package Exports
- ethereumjs-vm
- ethereumjs-vm/dist/exceptions
- ethereumjs-vm/dist/hooked
- ethereumjs-vm/dist/stateManager
This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (ethereumjs-vm) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.
Readme
SYNOPSIS
or #ethereumjs on freenode
Implements Ethereum's VM in Javascript.
Fork Support
Starting with the v2.5.0 release we now support both Byzantium and Constantinople fork rules - with Byzantium currently being the default (this will change in the future). See release notes for further details and have a look at the API docs on instructions how to instantiate the VM with the respective fork rules.
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')
//create a new VM instance
var vm = new VM()
var code = '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'
vm.runCode({
code: Buffer.from(code, 'hex'), // code needs to be a Buffer
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.