From 38c6e9b9fc245ca5e6e6cee2806cb64dcbd34e35 Mon Sep 17 00:00:00 2001
From: Sam Moore <matches@ucc.asn.au>
Date: Wed, 18 Jan 2012 21:36:47 +0800
Subject: [PATCH] pause AI in opponent's turn (Temporary)

This is a temporary and not entirely effective solution, to prevent AI from spamming CPU useage to make their opponents time out.
Yes I could use renice instead, but its just as easy for an AI to get around.

I will have to replace this with a better solution. But I don't have one at the moment.
---
 judge/manager/ai_controller.h |  2 ++
 judge/manager/controller.cpp  |  2 ++
 judge/manager/controller.h    |  4 ++++
 judge/manager/game.cpp        |  6 ++++--
 judge/manager/program.cpp     | 36 ++++++++++++++++++++++++++++++++++-
 judge/manager/program.h       |  5 ++++-
 6 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/judge/manager/ai_controller.h b/judge/manager/ai_controller.h
index ee053e6..f4682eb 100644
--- a/judge/manager/ai_controller.h
+++ b/judge/manager/ai_controller.h
@@ -20,6 +20,8 @@ class AI_Controller : public Controller, private Program
 		virtual MovementResult QueryMove(std::string & buffer);
 
 		virtual void Message(const char * message) {Program::SendMessage(message);}
+		virtual void Pause() {Program::Pause();} //Hack wrapper
+		virtual void Continue() {Program::Continue();} //Hack wrapper
 
 		virtual bool Valid() const {return Program::Running();}
 
diff --git a/judge/manager/controller.cpp b/judge/manager/controller.cpp
index 5691406..3a78e9b 100644
--- a/judge/manager/controller.cpp
+++ b/judge/manager/controller.cpp
@@ -188,3 +188,5 @@ MovementResult Controller::MakeMove(string & buffer)
 	return moveResult; 	
 
 }
+
+
diff --git a/judge/manager/controller.h b/judge/manager/controller.h
index 55c233d..5aa6364 100644
--- a/judge/manager/controller.h
+++ b/judge/manager/controller.h
@@ -28,6 +28,10 @@ class Controller
 		virtual MovementResult QueryMove(std::string & buffer) = 0;
 		virtual bool Valid() const {return true;}
 
+
+		virtual void Pause() {} 	// Hack function (AI_Controller ONLY will overwrite with wrapper to Program::Pause)
+		virtual void Continue() {}	// Hack function (AI_Controller '' '' wrapper to Program::Continue)
+
 		const Piece::Colour colour; 
 
 		std::string name;
diff --git a/judge/manager/game.cpp b/judge/manager/game.cpp
index 486920d..8d3eef0 100644
--- a/judge/manager/game.cpp
+++ b/judge/manager/game.cpp
@@ -498,7 +498,8 @@ MovementResult Game::Play()
 		#endif //BUILD_GRAPHICS
 		
 		turn = Piece::RED;
-
+		blue->Pause();
+		red->Continue();
 		if (!Board::HaltResult(result))
 		{
 			result = CheckVictoryAttrition();
@@ -542,7 +543,8 @@ MovementResult Game::Play()
 		
 		
 		turn = Piece::BLUE;
-
+		red->Pause();
+		blue->Continue();
 		if (!Board::HaltResult(result))
 		{
 			result = CheckVictoryAttrition();
diff --git a/judge/manager/program.cpp b/judge/manager/program.cpp
index d5463f4..031d411 100644
--- a/judge/manager/program.cpp
+++ b/judge/manager/program.cpp
@@ -20,7 +20,7 @@ using namespace std;
  *	The child process closes unused sides of the pipe, and then calls exec to replace itself with the AI program
  *	The parent process closes unused sides of the pipe, and sets up member variables - associates streams with the pipe fd's for convenience.
  */
-Program::Program(const char * executablePath) : input(NULL), output(NULL), pid(0)
+Program::Program(const char * executablePath) : input(NULL), output(NULL), pid(0), paused(false)
 {
 	//See if file exists and is executable...
 	if (access(executablePath, X_OK) != 0)
@@ -100,8 +100,42 @@ Program::~Program()
 	
 }
 
+/**
+ * Forces the program to pause by sending SIGSTOP
+ * Program can be resumed by calling Continue() (which sends SIGCONT)
+ * @returns true if the program could be paused, false if it couldn't (probably because it wasn't running)
+ */
+bool Program::Pause()
+{
+	if (pid > 0 && kill(pid,SIGSTOP) == 0)
+	{
+		paused = true;
+		return true;
+	}
+	return false;
+}
 
+/**
+ * Causes a paused program to continue
+ * @returns true if the program could be continued, false if it couldn't (probably because it wasn't running)
+ */
+bool Program::Continue()
+{
+	if (pid > 0 && kill(pid,SIGCONT) == 0)
+	{
+		paused = false;
+		return true;
+	}
+	return false;
+}
 
+/**
+ * @returns true iff the program is paused
+ */
+bool Program::Paused() const
+{
+	return paused;
+}
 
 
 /**
diff --git a/judge/manager/program.h b/judge/manager/program.h
index 01e00bc..b01ce00 100644
--- a/judge/manager/program.h
+++ b/judge/manager/program.h
@@ -24,7 +24,9 @@ class Program
 		bool GetMessage(std::string & buffer, double timeout=-1); //Retrieves a message, or waits for a timeout (if positive)
 
 		bool Running() const;
-
+		bool Paused() const;
+		bool Pause();
+		bool Continue();
 		
 
 	protected:
@@ -33,6 +35,7 @@ class Program
 
 	private:
 		pid_t pid; //Process ID of the program wrapped
+		bool paused;
 		
 };
 
-- 
2.20.1