From 9baf77180794602c72d793d36a8477de270ed2fa Mon Sep 17 00:00:00 2001
From: Petr Baudis <pasky@ucw.cz>
Date: Thu, 22 Dec 2011 15:28:05 +0100
Subject: [PATCH] Incomp. Proto. Change: Maintain sync by prefixing client
 commands by tick id

---
 README            | 15 +++++++++++----
 agent.cc          |  2 +-
 client/example.pl |  4 ++--
 connection.cc     | 21 ++++++++++++++-------
 connection.h      |  2 +-
 5 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/README b/README
index 937314b..dac649a 100644
--- a/README
+++ b/README
@@ -6,7 +6,7 @@ In each tick, the server sends sensor input to the agent.
 Until the next tick, the client may supply actions to take
 to the server.
 
-Both server input and client output follow the same format:
+Server input follows the format:
 
 	cmd1 <par1> <par2>...
 	cmd2 <par1> <par2>...
@@ -53,6 +53,16 @@ The following inputs (in no particular order) are supported:
 			<id>: pheromone id 0..65535
 			<intensity>: floating-point number
 
+Client output follows a slightly different format:
+
+	<tickid> cmd1 <par1> <par2>...
+	<tickid> cmd2 <par1> <par2>...
+	...
+
+Only commands with a matching tickid are processed; in case a command
+is delayed, causing late relaying to the server and processing in the
+future, it is silently dropped and ignored.
+
 The following outputs are supported:
 
 	move_dir <x> <y>
@@ -106,6 +116,3 @@ If the id corresponds to a disconnected agent, the connection
 is immediately attached to that agent. Combining this with other
 negotiation commands is undefined, except for newborns - in that case,
 negotiation commands must follow after agent_id.
-
-TODO proto. change:
-	tickid for input
diff --git a/agent.cc b/agent.cc
index 237a341..d3090b4 100644
--- a/agent.cc
+++ b/agent.cc
@@ -179,7 +179,7 @@ agent::on_action_takes(void)
 		return;
 	}
 
-	conn->actions(this);
+	conn->actions(tick_id, this);
 }
 
 void
diff --git a/client/example.pl b/client/example.pl
index 9bbc82f..2ada3ca 100755
--- a/client/example.pl
+++ b/client/example.pl
@@ -116,9 +116,9 @@ sub take_action($$) {
 	print "moves ".join(", ", @move)." => (".dirindex($max).":$max->[0],$max->[1])\n";
 
 	if ($attack[dirindex($max)]) {
-		print $socket "attack_dir $max->[0] $max->[1] 100\r\n";
+		print $socket $state->{tick}." attack_dir $max->[0] $max->[1] 100\r\n";
 	} else {
-		print $socket "move_dir $max->[0] $max->[1]\r\n";
+		print $socket $state->{tick}." move_dir $max->[0] $max->[1]\r\n";
 	}
 	print $socket "secrete 65536 1\r\n";
 	print $socket "\r\n";
diff --git a/connection.cc b/connection.cc
index eaa90f6..20579df 100644
--- a/connection.cc
+++ b/connection.cc
@@ -6,6 +6,8 @@
 
 #include <sys/select.h>
 #include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 #include "agent.h"
@@ -97,22 +99,31 @@ connection::bump(void)
 }
 
 void
-connection::actions(class agent *agent)
+connection::actions(int tick_id, class agent *agent)
 {
 	pthread_mutex_lock(&buf_lock);
-	if (buf_incomplete(in_buf)) {
+	if (in_buf.find("\r\n") == std::string::npos) {
 		/* Not enough data, needs to wait until next turn, sorry. */
 		pthread_mutex_unlock(&buf_lock);
 		return;
 	}
 
 	int mask = 0;
-	while (in_buf.c_str()[0] != '\r') {
+	while (in_buf.find("\r\n") != std::string::npos) {
 		int nlofs = in_buf.find("\r\n");
 		std::string line = in_buf.substr(0, nlofs);
 		in_buf.erase(0, nlofs + 2);
 
 		int spofs = line.find(' ');
+		std::string cmd_tick_id = line.substr(0, spofs);
+		line.erase(0, spofs + 1);
+
+		if (atol(cmd_tick_id.c_str()) != tick_id - 1) {
+			/* Out of sync command, ignore and continue. */
+			continue;
+		}
+
+		spofs = line.find(' ');
 		std::string cmd = line.substr(0, spofs);
 		line.erase(0, spofs + 1);
 
@@ -282,13 +293,9 @@ connection::thread_loop(void)
 				break;
 
 			} else {
-				bool want_moar = false;
 				pthread_mutex_lock(&buf_lock);
 				in_buf += std::string(cbuf, len);
-				want_moar = buf_incomplete(in_buf);
 				pthread_mutex_unlock(&buf_lock);
-				if (!want_moar)
-					break;
 			}
 		}
 
diff --git a/connection.h b/connection.h
index 7c4722f..8389f2e 100644
--- a/connection.h
+++ b/connection.h
@@ -29,7 +29,7 @@ public:
 
 	void senses(int tick_id, class agent &);
 	void bred(int agent_id, std::string &info);
-	void actions(class agent *);
+	void actions(int tick_id, class agent *);
 
 	void cancel(void);