multiple chunks on server and unload not near players. just need client to req chunks now

2 files changed, 108 insertions, 38 deletions

diff --git a/server/main.ha b/server/main.ha
index 1dffbb5..19ecc51 100644
--- a/server/main.ha
+++ b/server/main.ha
@@ -15,15 +15,15 @@ use time;
 use unix::poll;
 
 use drawing;
-use drawing::{pos};
+use drawing::{pos,CHUNKSIZE};
 use packet_reader;
 
 
 def PORT: u16 = 41460;
-def CHUNKSIZE = 512;
 
 type server_state = struct {
 	connections: []connection,
+	// nb we use 'picture' and 'chunk' interchangeably
 	pictures: []drawing::picture,
 	listener: net::socket,
 	running: bool
@@ -39,20 +39,13 @@ type connection = struct {
 def save_interval = 20 * time::SECOND;
 
 export fn main() void = {
-	// create 4 pictures. later we will have more pictures
-	// but for now there are just 4, and they are at fixed positions
-	const offs: [_]pos = [
-		(0,0), (0,CHUNKSIZE), (CHUNKSIZE,0), (CHUNKSIZE,CHUNKSIZE),
-	];
-
-	let pictures: []drawing::picture = alloc([],len(offs));
-	for (let i = 0z; i < len(offs); i +=1){
-		append(pictures, match (load_picture_from_file(offs[i])) {
-			case let pic: drawing::picture => yield pic;
-			case let err: fs::error => fmt::fatal(fs::strerror(err));
-			case bad_header => fmt::fatal("bad ppm header");
-		});
-	};
+	// for (let i = 0z; i < len(offs); i +=1){
+	// 	append(pictures, match (load_picture_from_file(offs[i])) {
+	// 		case let pic: drawing::picture => yield pic;
+	// 		case let err: fs::error => fmt::fatal(fs::strerror(err));
+	// 		case bad_header => fmt::fatal("bad ppm header");
+	// 	});
+	// };
 
 	const listener = match (
 		tcp::listen(ip::ANY_V4, PORT, tcp::reuseaddr)
@@ -65,7 +58,7 @@ export fn main() void = {
 
 	let state = server_state {
 		connections = [],
-		pictures = pictures,
+		pictures = [],
 		listener = listener,
 		running = true,
 	};
@@ -75,7 +68,7 @@ export fn main() void = {
 	
 	for (state.running) {
 		const timeout = time::diff(now, next);
-		fmt::println("running loop, timeout {}",timeout)!;
+		fmt::printfln("running loop, timeout {} sec",timeout/time::SECOND)!;
 		loop(&state, timeout);
 
 		now = time::now(time::clock::MONOTONIC);
@@ -87,11 +80,9 @@ export fn main() void = {
 			case void => yield;
 			};
 			next = time::add(now, save_interval);
+			unload_distant_chunks(&state);
 		};
 	};
-
-
-
 };
 
 fn loop(state: *server_state, timeout: time::duration) void = {
@@ -123,7 +114,14 @@ fn loop(state: *server_state, timeout: time::duration) void = {
 		});
 		fmt::printfln("there are now {} connections",
 			len(state.connections))!;
-		greet_connection(state, len(state.connections));
+		const conn_idx = len(state.connections) - 1;
+		match (greet_connection(state, conn_idx)) {
+		case void => yield;
+		case let e: io::error =>
+			fmt::printfln("error greeting {}: {}",conn_idx,
+				io::strerror(e))!;
+			delete(state.connections[conn_idx]);
+		};
 	};
 
 	// for each connection, handle packet(s)
@@ -131,7 +129,8 @@ fn loop(state: *server_state, timeout: time::duration) void = {
 	// try to look at the nonexistent pollfd for a connection we just accepted
 	for (let pollfd_idx = 1z: size; pollfd_idx < len(pollfds); pollfd_idx += 1) {
 		const conn_idx = pollfd_idx - 1;
-		fmt::println("checking conn {} with pollfd {}",conn_idx, pollfd_idx)!;
+		if (state.connections[conn_idx].should_delete) continue;
+		fmt::printfln("checking conn {} with pollfd {}",conn_idx, pollfd_idx)!;
 		if (0 != pollfds[conn_idx+1].revents & poll::event::POLLIN) {
 			read_from_connection(state, conn_idx);
 		};
@@ -141,6 +140,7 @@ fn loop(state: *server_state, timeout: time::duration) void = {
 
 };
 
+// kicks connections in an error state
 fn perform_deletions(state: *server_state) void = {
 	for (let i1 = len(state.connections); i1 > 0; i1 -= 1) {
 		const i = i1 - 1;
@@ -152,7 +152,9 @@ fn perform_deletions(state: *server_state) void = {
 	};
 };
 
-fn greet_connection(state: *server_state, conn_idx: size) void = void;
+fn greet_connection(state: *server_state, conn_idx: size)
+(void|io::error) = void;
+
 
 
 fn read_from_connection(state: *server_state, conn_idx: size) void = {
@@ -166,10 +168,17 @@ fn read_from_connection(state: *server_state, conn_idx: size) void = {
 		conn.should_delete = true;
 	case void =>
 		for (true) match (packet_reader::next(&conn.pr)) {
-			// foreach loop seems to break match exhaustivity here
+			// xxx foreach loop seems to break match exhaustivity here
+			// investigate that at some point
 			case done => break;
 			case let p: packet_reader::packet =>
-				handle_packet(state, conn_idx, p);
+				match (handle_packet(state, conn_idx, p)) {
+				case void => yield;
+				case let e: io::error =>
+					fmt::printfln("handle packet error. #{}. {}",
+						conn_idx, io::strerror(e))!;
+					conn.should_delete = true;
+				};
 			case let e: packet_reader::error =>
 				fmt::printfln("packet error {}",e)!;
 				conn.should_delete = true;
@@ -181,11 +190,13 @@ fn handle_packet(
 	state: *server_state,
 	conn_idx: size,
 	packet: packet_reader::packet
-) void = {
+) (void|io::error) = {
+	const conn = &state.connections[conn_idx];
 	match (packet) {
 	case let op: packet_reader::packet_drawop =>
 		const opc = op as drawing::op_circle;
-		fmt::printfln("#{}: drawop  ({:+6},{:+6})",conn_idx,opc.0,opc.1)!;
+		fmt::printfln("#{}: drawop  ({:+6},{:+6})",
+			conn_idx,opc.0,opc.1)!;
 		drawing::perform(state.pictures, opc);
 		for (let other_idx = 0z;
 				other_idx < len(state.connections);
@@ -203,19 +214,78 @@ fn handle_packet(
 				other_conn.should_delete = true;
 			};
 		};
+	case let pos: packet_reader::packet_position =>
+		fmt::printfln("pos of #{} is now {},{}",
+			conn_idx, pos.0, pos.1)!;
+		state.connections[conn_idx].pos = pos;
+	case let world_pos: packet_reader::packet_reqchunk =>
+		// xxx it is probably easy to ddos the server by sending lots of these
+		fmt::printfln("#{} requests chunk {},{}",
+			conn_idx, world_pos.0, world_pos.1)!;
+
+		const pic = ensure_chunk(state, world_pos);
+		packet_reader::send(conn.sock, packet_reader::packet_sendchunk {
+				world_pos = world_pos,
+				chunk_data = pic.d[..pic.w*pic.h],
+		})?;
+
 	case =>
-		fmt::printfln("shouldn't be getting other packets from #{}",conn_idx)!;
+		fmt::printfln("shouldn't be getting other packets from #{}",
+			conn_idx)!;
 		state.connections[conn_idx].should_delete = true;
 	};
 };
 
-fn send_world(conn: io::file, pictures: []drawing::picture) (void | io::error) = {
-	for (const pic &.. pictures) {
-		fmt::printfln("  sending {},{}",pic.world_pos.0, pic.world_pos.1)!;
-		packet_reader::send(conn, packet_reader::packet_sendchunk {
-			world_pos = pic.world_pos,
-			chunk_data = pic.d[..pic.w*pic.h],
-		})?;
+fn ensure_chunk(state: *server_state, world_pos: pos) *drawing::picture = {
+	// if that chunk is already loaded, do nothing
+	// if not, load it from disk, or create it newly if not on disk
+	// in either case, return it
+	for (const pic &.. state.pictures) {
+		if (pic.world_pos.0 == world_pos.0 && pic.world_pos.1 == world_pos.1) {
+			return pic;
+		};
 	};
 
+	const pic = load_picture_from_file(world_pos)!;
+	append(state.pictures, pic);
+	return &state.pictures[len(state.pictures)-1];
+};
+
+fn floor_div(a: i32, b: i32) i32 = {
+	if (a < 0) return -1-floor_div(-(a+1),b);
+	return a / b;
 };
+
+fn unload_distant_chunks(state: *server_state) void = {
+	const n_pics = len(state.pictures);
+	let should_unload = alloc([true...], n_pics);
+	defer free(should_unload);
+
+	for (const conn &.. state.connections) {
+		const chunk_in_x = floor_div(conn.pos.0, CHUNKSIZE)*CHUNKSIZE;
+		const chunk_in_y = floor_div(conn.pos.1, CHUNKSIZE)*CHUNKSIZE;
+		// pic_chunk_pos - player_chunk_pos must be either 0 or 512 or 1024
+		// can't be less than 0 or more than 1024
+
+		for (let i = 0z; i < n_pics; i += 1) {
+			const pic = &state.pictures[i];
+			const dcx = pic.world_pos.0 - chunk_in_x;
+			const dcy = pic.world_pos.1 - chunk_in_y;
+			if (0 <= dcx && dcx <= 2*CHUNKSIZE && 0 <= dcy && dcy <= 2*CHUNKSIZE)
+				should_unload[i] = false;
+		};
+	};
+
+	for (let i1 = n_pics; i1 > 0; i1 -= 1) {
+		const i = i1 - 1;
+		if (should_unload[i]) {
+			fmt::printfln("unloading {},{}",
+				state.pictures[i].world_pos.0,
+				state.pictures[i].world_pos.1)!;
+			delete(state.pictures[i]);
+		};
+	};
+};
+
+
+
diff --git a/server/save_load.ha b/server/save_load.ha
index cf82a0d..db5a18a 100644
--- a/server/save_load.ha
+++ b/server/save_load.ha
@@ -7,14 +7,13 @@ use os;
 use strings;
 
 use drawing;
-use drawing::{pos};
+use drawing::{pos,CHUNKSIZE};
 
 // caller should free return value
 fn filename_from_world_pos(pos: pos) str =
 	fmt::asprintf("./c.{}.{}.ppm",pos.0,pos.1);
 
 fn save_world(state: *server_state) (void | fs::error) = {
-	fmt::printfln("saving world!")!;
 	for (const pic &.. state.pictures) {
 		const filename = filename_from_world_pos(pic.world_pos);
 		fmt::printfln("\t-> {}",filename)!;
@@ -35,6 +34,7 @@ fn save_world(state: *server_state) (void | fs::error) = {
 			buf[3*i+2] = ((px)    &0xff): u8;
 		};
 		io::writeall(file, buf)?;
+
 	};
 		
 };