tspv: request previous headers recursively in order to support blockchain reorgs - electrum - Electrum Bitcoin wallet
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---
DIR commit 15a7626b1498d7cdd67e9db0b5b2b08cf5908229
DIR parent 1e15dbab814b98bbd3d0abacb7a329f7a84c0103
HTML Author: thomasv <thomasv@gitorious>
Date: Fri, 26 Oct 2012 13:43:20 +0200
spv: request previous headers recursively in order to support blockchain reorgs
Diffstat:
M lib/verifier.py | 43 +++++++++++++++----------------
1 file changed, 21 insertions(+), 22 deletions(-)
---
DIR diff --git a/lib/verifier.py b/lib/verifier.py
t@@ -25,7 +25,7 @@ from bitcoin import *
class WalletVerifier(threading.Thread):
- """ Simple Verification Protocol """
+ """ Simple Payment Verification """
def __init__(self, interface, config):
threading.Thread.__init__(self)
t@@ -76,14 +76,6 @@ class WalletVerifier(threading.Thread):
requested_chunks.append(i)
break
- # request missing headers
- if not requested_chunks and self.local_height:
- for i in range(self.local_height + 1, self.height + 1):
- if i not in requested_headers:
- print "requesting header", i
- self.interface.send([ ('blockchain.block.get_header',[i])], 'verifier')
- requested_headers.append(i)
-
# request missing tx merkle
for tx in self.transactions:
if tx not in self.verified_tx:
t@@ -127,12 +119,22 @@ class WalletVerifier(threading.Thread):
# process pending headers
if pending_headers_changed:
self.pending_headers.sort(key=lambda x: x.get('block_height'))
- print "pending headers", map(lambda x: x.get('block_height'), self.pending_headers)
+ # print "pending headers", map(lambda x: x.get('block_height'), self.pending_headers)
+ done = []
for header in self.pending_headers:
if self.verify_header(header):
- self.pending_headers.remove(header)
+ done.append(header)
else:
+ # request previous header
+ i = header.get('block_height') - 1
+ if i not in requested_headers:
+ print "requesting header", i
+ self.interface.send([ ('blockchain.block.get_header',[i])], 'verifier')
+ requested_headers.append(i)
+ # no point continuing
break
+
+ for header in done: self.pending_headers.remove(header)
pending_headers_changed = False
self.interface.trigger_callback('updated')
t@@ -192,7 +194,7 @@ class WalletVerifier(threading.Thread):
prev_header = self.read_header(height -1)
if not prev_header:
print "no previous header", height
- return
+ return False
#prev_hash = prev_header.get('block_height')
prev_hash = self.hash_header(prev_header)
t@@ -202,18 +204,14 @@ class WalletVerifier(threading.Thread):
assert prev_hash == header.get('prev_block_hash')
assert bits == header.get('bits')
assert eval('0x'+_hash) < target
- ok = True
except:
print "verify header failed", header
- raise
- # this could be caused by a reorg. request the previous header
- ok = False
- #request previous one
-
- if ok:
- self.save_header(header)
- print "verify header: ok", height
- return True
+ # this can be caused by a reorg. returning False will request the previous header.
+ return False
+
+ self.save_header(header)
+ print "verify header: ok", height
+ return True
t@@ -268,6 +266,7 @@ class WalletVerifier(threading.Thread):
self.set_local_height()
def save_header(self, header):
+ # todo: invalidate tx verifications if we rewind
data = self.header_to_string(header).decode('hex')
assert len(data) == 80
height = header.get('block_height')