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interface: further simplifications for fork resolution

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This commit is contained in:
SomberNight
2018-09-17 22:21:55 +02:00
parent b3a2bce213
commit 7221fb3231
2 changed files with 51 additions and 58 deletions
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55
electrum/interface.py
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@@ -448,6 +448,7 @@ class Interface(PrintError):
return await self._resolve_potential_chain_fork_given_forkpoint(good, bad, bad_header)
async def _search_headers_binary(self, height, bad, bad_header, chain):
assert bad == bad_header['block_height']
_assert_header_does_not_check_against_any_chain(bad_header)
self.blockchain = chain if isinstance(chain, Blockchain) else self.blockchain
@@ -467,7 +468,7 @@ class Interface(PrintError):
if good + 1 == bad:
break
mock = bad_header and 'mock' in bad_header and bad_header['mock']['connect'](height)
mock = 'mock' in bad_header and bad_header['mock']['connect'](height)
real = not mock and self.blockchain.can_connect(bad_header, check_height=False)
if not real and not mock:
raise Exception('unexpected bad header during binary: {}'.format(bad_header))
@@ -478,39 +479,49 @@ class Interface(PrintError):
async def _resolve_potential_chain_fork_given_forkpoint(self, good, bad, bad_header):
assert good + 1 == bad
assert bad == bad_header['block_height']
_assert_header_does_not_check_against_any_chain(bad_header)
# 'good' is the height of a block 'good_header', somewhere in self.blockchain.
# bad_header connects to good_header; bad_header itself is NOT in self.blockchain.
bh = self.blockchain.height()
assert bh >= good
if bh == good:
height = good + 1
self.print_error("catching up from {}".format(height))
return 'no_fork', height
# this is a new fork we don't yet have
height = bad + 1
branch = blockchain.blockchains.get(bad)
if branch is not None:
self.print_error("existing fork found at bad height {}".format(bad))
# Conflict!! As our fork handling is not completely general,
# we need to delete another fork to save this one.
# Note: This could be a potential DOS vector against Electrum.
# However, mining blocks that satisfy the difficulty requirements
# is assumed to be expensive; especially as forks below the max
# checkpoint are ignored.
self.print_error("new fork at bad height {}. conflict!!".format(bad))
ismocking = type(branch) is dict
height = bad + 1
if ismocking:
self.print_error("TODO replace blockchain")
return 'conflict', height
return 'fork_conflict', height
self.print_error('forkpoint conflicts with existing fork', branch.path())
branch.write(b'', 0)
branch.save_header(bad_header)
self.blockchain = branch
return 'conflict', height
return 'fork_conflict', height
else:
bh = self.blockchain.height()
self.print_error("no existing fork yet at bad height {}. local chain height: {}".format(bad, bh))
if bh > good:
forkfun = self.blockchain.fork if 'mock' not in bad_header else bad_header['mock']['fork']
b = forkfun(bad_header)
with blockchain.blockchains_lock:
assert bad not in blockchain.blockchains, (bad, list(blockchain.blockchains))
blockchain.blockchains[bad] = b
self.blockchain = b
height = b.forkpoint + 1
assert b.forkpoint == bad
return 'fork', height
else:
assert bh == good
self.print_error("catching up from %d" % (bh + 1))
height = bh + 1
return 'no_fork', height
# No conflict. Just save the new fork.
self.print_error("new fork at bad height {}. NO conflict.".format(bad))
forkfun = self.blockchain.fork if 'mock' not in bad_header else bad_header['mock']['fork']
b = forkfun(bad_header)
with blockchain.blockchains_lock:
assert bad not in blockchain.blockchains, (bad, list(blockchain.blockchains))
blockchain.blockchains[bad] = b
self.blockchain = b
assert b.forkpoint == bad
return 'fork_noconflict', height
async def _search_headers_backwards(self, height, header):
async def iterate():