verifier: download chunks first for efficiency

[electrum-nvc.git] / lib / verifier.py

diff --git a/lib/verifier.py b/lib/verifier.py
index dcb3808..012424f 100644 (file)
--- a/lib/verifier.py
+++ b/lib/verifier.py
@@ -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)
@@ -59,7 +59,7 @@ class WalletVerifier(threading.Thread):
         requested_merkle = []
         requested_chunks = []
         requested_headers = []
-        pending_headers_changed = False
+        all_chunks = False
         
         # subscribe to block headers
         self.interface.send([ ('blockchain.headers.subscribe',[])], 'verifier')
@@ -67,23 +67,18 @@ class WalletVerifier(threading.Thread):
         while True:
             # request missing chunks
             max_index = (self.height+1)/2016
-            if not requested_chunks:
+            if not all_chunks and self.height and not requested_chunks:
                 for i in range(0, max_index + 1):
                     # test if we can read the first header of the chunk
                     if self.read_header(i*2016): continue
-                    print "requesting chunk", i
+                    # print "requesting chunk", i
                     self.interface.send([ ('blockchain.block.get_chunk',[i])], 'verifier')
                     requested_chunks.append(i)
                     break
+                else:
+                    all_chunks = True
+                    print "all chunks"
 
-            # 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:
@@ -92,6 +87,25 @@ class WalletVerifier(threading.Thread):
                         self.request_merkle(tx)
                         #break
 
+
+            # process pending headers
+            if self.pending_headers and all_chunks:
+                done = []
+                for header in self.pending_headers:
+                    if self.verify_header(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)
+                self.interface.trigger_callback('updated')
+
             try:
                 r = self.interface.get_response('verifier',timeout=1)
             except Queue.Empty:
@@ -113,27 +127,18 @@ class WalletVerifier(threading.Thread):
                 self.verify_chunk(index, result)
                 requested_chunks.remove(index)
 
-            elif method == 'blockchain.headers.subscribe':
-                self.height = result.get('block_height')
-                self.pending_headers.append(result)
-                pending_headers_changed = True
+            elif method in ['blockchain.headers.subscribe', 'blockchain.block.get_header']:
 
-            elif method == 'blockchain.block.get_header':
-                height = result.get('block_height')
-                requested_headers.remove(height)
                 self.pending_headers.append(result)
-                pending_headers_changed = True
-
-            # process pending headers
-            if pending_headers_changed:
+                if method == 'blockchain.block.get_header':
+                    requested_headers.remove(result.get('block_height'))
+                else:
+                    self.height = result.get('block_height')
+                
                 self.pending_headers.sort(key=lambda x: x.get('block_height'))
-                print "pending headers", map(lambda x: x.get('block_height'), self.pending_headers)
-                for header in self.pending_headers:
-                    if self.verify_header(header):
-                        self.pending_headers.remove(header)
-                    else:
-                        break
-                pending_headers_changed = False
+                # print "pending headers", map(lambda x: x.get('block_height'), self.pending_headers)
+
+
 
             self.interface.trigger_callback('updated')
 
@@ -157,7 +162,7 @@ class WalletVerifier(threading.Thread):
         data = hexdata.decode('hex')
         height = index*2016
         num = len(data)/80
-        print "validate_chunk", index, num
+        print "validating headers", height, num
 
         if index == 0:  
             previous_hash = ("0"*64)
@@ -192,7 +197,7 @@ 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)
@@ -202,18 +207,14 @@ 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
         
 
             
@@ -268,6 +269,7 @@ 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')