signet/miner: add Generate.next_block_time function

contrib/signet/miner

@@ -213,13 +213,17 @@ class Generate:
     INTERVAL = 600.0*2016/2015 # 10 minutes, adjusted for the off-by-one bug
 
 
-    def __init__(self, multiminer=None, ultimate_target=None, poisson=False, max_interval=1800):
+    def __init__(self, multiminer=None, ultimate_target=None, poisson=False, max_interval=1800,
+                 standby_delay=0, backup_delay=0, set_block_time=None):
         if multiminer is None:
             multiminer = (0, 1, 1)
         (self.multi_low, self.multi_high, self.multi_period) = multiminer
         self.ultimate_target = ultimate_target
         self.poisson = poisson
         self.max_interval = max_interval
+        self.standby_delay = standby_delay
+        self.backup_delay = backup_delay
+        self.set_block_time = set_block_time
 
     def next_block_delta(self, last_nbits, last_hash):
         # strategy:
@@ -250,6 +254,42 @@ class Generate:
         det_rand = int(last_hash[-16:-8], 16)
         return self.multi_low <= (det_rand % self.multi_period) < self.multi_high
 
+    def next_block_time(self, now, bestheader, is_first_block):
+        if self.set_block_time is not None:
+            logging.debug("Setting start time to %d", self.set_block_time)
+            self.mine_time = self.set_block_time
+            self.action_time = now
+            self.is_mine = True
+        elif bestheader["height"] == 0:
+            time_delta = self.INTERVAL * 100 # plenty of time to mine 100 blocks
+            logging.info("Backdating time for first block to %d minutes ago" % (time_delta/60))
+            self.mine_time = now - time_delta
+            self.action_time = now
+            self.is_mine = True
+        else:
+            time_delta = self.next_block_delta(int(bestheader["bits"], 16), bestheader["hash"])
+            self.mine_time = bestheader["time"] + time_delta
+
+            self.is_mine = self.next_block_is_mine(bestheader["hash"])
+
+            self.action_time = self.mine_time
+            if not self.is_mine:
+                self.action_time += self.backup_delay
+
+            if self.standby_delay > 0:
+                self.action_time += self.standby_delay
+            elif is_first_block:
+                # for non-standby, always mine immediately on startup,
+                # even if the next block shouldn't be ours
+                self.action_time = now
+
+        # don't want fractional times so round down
+        self.mine_time = int(self.mine_time)
+        self.action_time = int(self.action_time)
+
+        # can't mine a block 2h in the future; 1h55m for some safety
+        self.action_time = max(self.action_time, self.mine_time - 6900)
+
 def do_generate(args):
     if args.max_blocks is not None:
         if args.ongoing:
@@ -308,7 +348,8 @@ def do_generate(args):
 
     ultimate_target = nbits_to_target(int(args.nbits,16))
 
-    gen = Generate(multiminer=my_blocks, ultimate_target=ultimate_target, poisson=args.poisson, max_interval=args.max_interval)
+    gen = Generate(multiminer=my_blocks, ultimate_target=ultimate_target, poisson=args.poisson, max_interval=args.max_interval,
+                   standby_delay=args.standby_delay, backup_delay=args.backup_delay, set_block_time=args.set_block_time)
 
     mined_blocks = 0
     bestheader = {"hash": None}
@@ -332,52 +373,18 @@ def do_generate(args):
 
         # when is the next block due to be mined?
         now = time.time()
-        if args.set_block_time is not None:
-            logging.debug("Setting start time to %d", args.set_block_time)
-            mine_time = args.set_block_time
-            action_time = now
-            is_mine = True
-        elif bestheader["height"] == 0:
-            time_delta = gen.next_block_delta(int(bestheader["bits"], 16), bci["bestblockhash"])
-            time_delta *= 100 # 100 blocks
-            logging.info("Backdating time for first block to %d minutes ago" % (time_delta/60))
-            mine_time = now - time_delta
-            action_time = now
-            is_mine = True
-        else:
-            time_delta = gen.next_block_delta(int(bestheader["bits"], 16), bci["bestblockhash"])
-            mine_time = bestheader["time"] + time_delta
-
-            is_mine = gen.next_block_is_mine(bci["bestblockhash"])
-
-            action_time = mine_time
-            if not is_mine:
-                action_time += args.backup_delay
-
-            if args.standby_delay > 0:
-                action_time += args.standby_delay
-            elif mined_blocks == 0:
-                # for non-standby, always mine immediately on startup,
-                # even if the next block shouldn't be ours
-                action_time = now
-
-        # don't want fractional times so round down
-        mine_time = int(mine_time)
-        action_time = int(action_time)
-
-        # can't mine a block 2h in the future; 1h55m for some safety
-        action_time = max(action_time, mine_time - 6900)
+        gen.next_block_time(now, bestheader, (mined_blocks == 0))
 
         # ready to go? otherwise sleep and check for new block
-        if now < action_time:
-            sleep_for = min(action_time - now, 60)
-            if mine_time < now:
+        if now < gen.action_time:
+            sleep_for = min(gen.action_time - now, 60)
+            if gen.mine_time < now:
                 # someone else might have mined the block,
                 # so check frequently, so we don't end up late
                 # mining the next block if it's ours
                 sleep_for = min(20, sleep_for)
-            minestr = "mine" if is_mine else "backup"
-            logging.debug("Sleeping for %s, next block due in %s (%s)" % (seconds_to_hms(sleep_for), seconds_to_hms(mine_time - now), minestr))
+            minestr = "mine" if gen.is_mine else "backup"
+            logging.debug("Sleeping for %s, next block due in %s (%s)" % (seconds_to_hms(sleep_for), seconds_to_hms(gen.mine_time - now), minestr))
             time.sleep(sleep_for)
             continue
 
@@ -390,20 +397,20 @@ def do_generate(args):
 
         logging.debug("GBT template: %s", tmpl)
 
-        if tmpl["mintime"] > mine_time:
-            logging.info("Updating block time from %d to %d", mine_time, tmpl["mintime"])
-            mine_time = tmpl["mintime"]
-            if mine_time > now:
-                logging.error("GBT mintime is in the future: %d is %d seconds later than %d", mine_time, (mine_time-now), now)
+        if tmpl["mintime"] > gen.mine_time:
+            logging.info("Updating block time from %d to %d", gen.mine_time, tmpl["mintime"])
+            gen.mine_time = tmpl["mintime"]
+            if gen.mine_time > now:
+                logging.error("GBT mintime is in the future: %d is %d seconds later than %d", gen.mine_time, (gen.mine_time-now), now)
                 return 1
 
         # address for reward
         reward_addr, reward_spk = get_reward_addr_spk(args, tmpl["height"])
 
         # mine block
-        logging.debug("Mining block delta=%s start=%s mine=%s", seconds_to_hms(mine_time-bestheader["time"]), mine_time, is_mine)
+        logging.debug("Mining block delta=%s start=%s mine=%s", seconds_to_hms(gen.mine_time-bestheader["time"]), gen.mine_time, gen.is_mine)
         mined_blocks += 1
-        psbt = generate_psbt(tmpl, reward_spk, blocktime=mine_time)
+        psbt = generate_psbt(tmpl, reward_spk, blocktime=gen.mine_time)
         input_stream = os.linesep.join([psbt, "true", "ALL"]).encode('utf8')
         psbt_signed = json.loads(args.bcli("-stdin", "walletprocesspsbt", input=input_stream))
         if not psbt_signed.get("complete",False):
@@ -417,7 +424,7 @@ def do_generate(args):
         r = args.bcli("-stdin", "submitblock", input=block.serialize().hex().encode('utf8'))
 
         # report
-        bstr = "block" if is_mine else "backup block"
+        bstr = "block" if gen.is_mine else "backup block"
 
         next_delta = gen.next_block_delta(block.nBits, block.hash)
         next_delta += block.nTime - time.time()