fix and improve clarity

diff --git a/backends/bitcoind/blockchain_processor.py b/backends/bitcoind/blockchain_processor.py
index 73fe481..f92f6e4 100644 (file)
--- a/backends/bitcoind/blockchain_processor.py
+++ b/backends/bitcoind/blockchain_processor.py
@@ -90,14 +90,13 @@ class BlockchainProcessor(Processor):
 
         try:
             hist = self.deserialize(self.db.Get('0'))
-            hh, self.height, _ = hist[0] 
-            self.block_hashes = [hh]
+            self.last_hash, self.height, _ = hist[0] 
             print_log( "hist", hist )
         except:
             #traceback.print_exc(file=sys.stdout)
             print_log('initializing database')
             self.height = 0
-            self.block_hashes = [ '000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f' ]
+            self.last_hash = '000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f'
 
         # catch_up headers
         self.init_headers(self.height)
@@ -159,28 +158,29 @@ class BlockchainProcessor(Processor):
         self.chunk_cache = {}
         self.headers_filename = os.path.join( self.dbpath, 'blockchain_headers')
 
-        height = 0
         if os.path.exists(self.headers_filename):
-            height = os.path.getsize(self.headers_filename)/80
-
-        if height:
-            prev_header = self.read_header(height -1)
-            prev_hash = self.hash_header(prev_header)
+            height = os.path.getsize(self.headers_filename)/80 - 1   # the current height
+            if height > 0:
+                prev_hash = self.hash_header(self.read_header(height))
+            else:
+                prev_hash = None
         else:
             open(self.headers_filename,'wb').close()
             prev_hash = None
+            height = -1
 
-        if height != db_height:
+        if height < db_height:
             print_log( "catching up missing headers:", height, db_height)
 
-        s = ''
         try:
-            for i in range(height, db_height):
-                header = self.get_header(i)
-                assert prev_hash == header.get('prev_block_hash')
+            while height != db_height:
+                height = height + 1
+                header = self.get_header(height)
+                if height>1: 
+                    assert prev_hash == header.get('prev_block_hash')
                 self.write_header(header, sync=False)
                 prev_hash = self.hash_header(header)
-                if i%1000==0: print_log("headers file:",i)
+                if height%1000==0: print_log("headers file:",height)
         except KeyboardInterrupt:
             self.flush_headers()
             sys.exit()
@@ -214,6 +214,7 @@ class BlockchainProcessor(Processor):
     def write_header(self, header, sync=True):
         if not self.headers_data:
             self.headers_offset = header.get('block_height')
+
         self.headers_data += header_to_string(header).decode('hex')
         if sync or len(self.headers_data) > 40*100:
             self.flush_headers()
@@ -576,11 +577,16 @@ class BlockchainProcessor(Processor):
 
 
 
-    def last_hash(self):
-        return self.block_hashes[-1]
+    def catch_up(self, sync = True):
+        #        
+        #                     -------> F ------> G -------> H
+        #                    /
+        #                   /
+        #        A ------> B --------> C ------> E
+        #        
+        #        we always compare the hash in the headers file to the hash returned by bitcoind
 
 
-    def catch_up(self, sync = True):
         t1 = time.time()
 
         while not self.shared.stopped():
@@ -589,45 +595,44 @@ class BlockchainProcessor(Processor):
             info = self.bitcoind('getinfo')
             bitcoind_height = info.get('blocks')
             bitcoind_block_hash = self.bitcoind('getblockhash', [bitcoind_height])
-            if self.last_hash() == bitcoind_block_hash: 
+            if self.last_hash == bitcoind_block_hash: 
                 self.up_to_date = True
                 break
 
             # not done..
             self.up_to_date = False
-            block_hash = self.bitcoind('getblockhash', [self.height+1])
-            block = self.bitcoind('getblock', [block_hash, 1])
+            next_block_hash = self.bitcoind('getblockhash', [self.height+1])
+            next_block = self.bitcoind('getblock', [block_hash, 1])
 
-            if block.get('previousblockhash') == self.last_hash():
+            if next_block.get('previousblockhash') == self.last_hash:
 
-                self.import_block(block, block_hash, self.height+1, sync)
+                self.import_block(next_block, next_block_hash, self.height+1, sync)
                 self.height = self.height + 1
-                self.write_header(self.block2header(block), sync)
-
-                self.block_hashes.append(block_hash)
-                self.block_hashes = self.block_hashes[-10:]
+                self.write_header(self.block2header(next_block), sync)
+                self.last_hash = next_block_hash
 
                 if (self.height+1)%100 == 0 and not sync: 
                     t2 = time.time()
                     print_log( "catch_up: block %d (%.3fs)"%( self.height, t2 - t1 ) )
                     t1 = t2
-
                     
             else:
                 # revert current block
-                print_log( "bc2: reorg", self.height, block.get('previousblockhash'), self.last_hash() )
-                block_hash = self.last_hash()
-                block = self.bitcoind('getblock', [block_hash, 1])
-                self.height = self.height -1
+                block = self.bitcoind('getblock', [self.last_hash, 1])
+                print_log( "bc2: reorg", self.height, block.get('previousblockhash'), self.last_hash )
+                self.import_block(block, self.last_hash, self.height, revert=True)
                 self.pop_header()
 
-                self.block_hashes.remove(block_hash)
-                self.import_block(block, self.last_hash(), self.height, revert=True)
+                self.height = self.height -1
+
+                # read previous header from disk
+                self.header = self.read_header(self.height) 
+                self.last_hash = self.hash_header(self.header)
         
 
-        self.header = self.block2header(self.bitcoind('getblock', [self.last_hash()]))
+        self.header = self.block2header(self.bitcoind('getblock', [self.last_hash]))
+
 
-        
 
             
     def memorypool_update(self):