abstract check_pow to header_check in consensus strategy

Author: Jan Xie

ethereum/block.py

@@ -7,7 +7,6 @@
 from ethereum.trie import Trie
 from ethereum.securetrie import SecureTrie
 from config import default_config
-from ethereum.ethpow import check_pow
 from ethereum.transactions import Transaction
 from db import BaseDB
 import sys
@@ -107,18 +106,6 @@ def mining_hash(self):
     def signing_hash(self):
         return utils.sha3(rlp.encode(self, BlockHeader.exclude(['extra_data'])))
 
-    def check_pow(self, nonce=None):
-        """Check if the proof-of-work of the block is valid.
-
-        :param nonce: if given the proof of work function will be evaluated
-                      with this nonce instead of the one already present in
-                      the header
-        :returns: `True` or `False`
-        """
-        # log.debug('checking pow', block=encode_hex(self.hash())[:8])
-        return check_pow(self.number, self.mining_hash, self.mixhash, nonce or self.nonce,
-                         self.difficulty)
-
     def to_dict(self):
         """Serialize the header to a readable dictionary."""
         d = {}

ethereum/consensus_strategy.py

@@ -1,5 +1,6 @@
 class ConsensusStrategy(object):
-    def __init__(self, header_validate, uncle_validate, block_setup, block_pre_finalize, block_post_finalize, state_initialize):
+    def __init__(self, header_check, header_validate, uncle_validate, block_setup, block_pre_finalize, block_post_finalize, state_initialize):
+        self.header_check=header_check
         self.header_validate=header_validate
         self.uncle_validate=uncle_validate
         self.block_setup=block_setup
@@ -9,8 +10,11 @@ def __init__(self, header_validate, uncle_validate, block_setup, block_pre_final
 
 def get_consensus_strategy(config):
     if config['CONSENSUS_STRATEGY'] in ('pow', 'ethpow', 'ethash', 'ethereum1'):
-        from ethpow_utils import ethereum1_validate_header, ethereum1_validate_uncle, ethereum1_pre_finalize_block, ethereum1_post_finalize_block, ethereum1_setup_block
+        from ethpow_utils import ethereum1_check_header, ethereum1_validate_header, \
+                                 ethereum1_validate_uncle, ethereum1_pre_finalize_block, \
+                                 ethereum1_post_finalize_block, ethereum1_setup_block
         return ConsensusStrategy(
+            header_check=ethereum1_check_header,
             header_validate=ethereum1_validate_header,
             uncle_validate=ethereum1_validate_uncle,
             block_setup=ethereum1_setup_block,
@@ -21,6 +25,7 @@ def get_consensus_strategy(config):
     elif config['CONSENSUS_STRATEGY'] == 'casper':
         from casper_utils import casper_validate_header, casper_state_initialize, casper_post_finalize_block, casper_setup_block
         return ConsensusStrategy(
+            header_check=None,
             header_validate=casper_validate_header,
             uncle_validate=None,
             block_setup=casper_setup_block,

ethereum/ethpow_utils.py

@@ -1,14 +1,15 @@
-from ethereum import ethash, ethash_utils, utils
-from ethereum.block import Block, BlockHeader
 import time
 import sys
-from ethereum.utils import sha3
 import warnings
+import rlp
 from collections import OrderedDict
+from ethereum import ethash, ethash_utils, utils
+from ethereum.block import Block, BlockHeader
+from ethereum.utils import sha3
 from ethereum.slogging import get_logger
-import rlp
-from ethereum.state_transition import calc_difficulty, check_gaslimit, \
-    initialize
+from ethereum.ethpow import check_pow
+from ethereum.state_transition import calc_difficulty, check_gaslimit, initialize, \
+                                      check_block_header
 from ethereum.config import default_config
 from ethereum.exceptions import VerificationFailed
 
@@ -62,8 +63,20 @@ def ethereum1_setup_block(chain, state=None, timestamp=None, coinbase='\x35'*20,
     return blk
 
 
+def ethereum1_check_header(header, nonce=None):
+    """Check if the proof-of-work of the block is valid.
+
+    :param nonce: if given the proof of work function will be evaluated
+                  with this nonce instead of the one already present in
+                  the header
+    :returns: `True` or `False`
+    """
+    # log.debug('checking pow', block=encode_hex(self.hash())[:8])
+    return check_pow(header.number, header.mining_hash, header.mixhash,
+                     nonce or header.nonce, header.difficulty)
+
 def ethereum1_validate_header(state, header):
-    assert header.check_pow()
+    assert check_block_header(state, header)
     parent = state.prev_headers[0]
     if parent:
         if header.prevhash != parent.hash:
@@ -91,7 +104,7 @@ def ethereum1_validate_header(state, header):
     return True
 
 def ethereum1_validate_uncle(state, uncle):
-    if not uncle.check_pow():
+    if not check_block_header(state, uncle):
         raise VerificationFailed('pow mismatch')
     return True
 

ethereum/state_transition.py

@@ -295,9 +295,19 @@ def mk_receipt_sha(receipts):
 mk_transaction_sha = mk_receipt_sha
 
 
+def check_block_header(state, header, **kwargs):
+    """ Check header's internal validity """
+    cs = get_consensus_strategy(state.config)
+    if cs.header_check:
+        return cs.header_check(header, **kwargs)
+    return True
+
+
 def validate_block_header(state, header):
+    """ Check header's validity in block context """
     cs = get_consensus_strategy(state.config)
-    cs.header_validate(state, header)
+    if cs.header_validate:
+        cs.header_validate(state, header)
     return True