This commit implements a dual state approach. The dual state approach
separates public and private state by making the core vm environment
context aware.
Although not currently implemented it will need to prohibit value
transfers and it must initialise all transactions from accounts on the
public state. This means that sending transactions increments the
account nonce on the public state and contract addresses are derived
from the public state when initialised by a transaction. For obvious
reasons, contract created by private contracts are still derived from
public state.
This is required in order to have consensus over the public state at all
times as non-private participants would still process the transaction on
the public state even though private payload can not be decrypted. This
means that participants of a private group must do the same in order to
have public consensus. However the creation of the contract and
interaction still occurs on the private state.
It implements support for the following calling model:
S: sender, (X): private, X: public, ->: direction, [ ]: read only mode
1. S -> A -> B
2. S -> (A) -> (B)
3. S -> (A) -> [ B -> C ]
It does not support
1. (S) -> A
2. (S) -> (A)
3. S -> (A) -> B
Implemented "read only" mode for the EVM. Read only mode is checked
during any opcode that could potentially modify the state. If such an
opcode is encountered during "read only", it throws an exception.
The EVM is flagged "read only" when a private contract calls in to
public state.
* Removed some strange code that didn't apply state reverting properly
* Refactored code setting from vm & state transition to the executioner
* Updated tests
* change gas cost for contract creating txs
* invalidate signature with s value greater than secp256k1 N / 2
* OOG contract creation if not enough gas to store code
* new difficulty adjustment algorithm
* new DELEGATECALL op code
* Moved `vm.Transfer` to `core` package and changed execution to call
`env.Transfer` instead of `core.Transfer` directly.
* core/vm: byte code VM moved to jump table instead of switch
* Moved `vm.Transfer` to `core` package and changed execution to call
`env.Transfer` instead of `core.Transfer` directly.
* Byte code VM now shares the same code as the JITVM
* Renamed Context to Contract
* Changed initialiser of state transition & unexported methods
* Removed the Execution object and refactor `Call`, `CallCode` &
`Create` in to their own functions instead of being methods.
* Removed the hard dep on the state for the VM. The VM now
depends on a Database interface returned by the environment. In the
process the core now depends less on the statedb by usage of the env
* Moved `Log` from package `core/state` to package `core/vm`.
Patrick Mylund Nielsen
Jeffrey Wilcke
Benjamin Brent
Jeffrey Wilcke
Gustav Simonsson
Felix Lange