From ca207b038bf4c150f008042e1bf3a102e68880ca Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Fri, 14 Apr 2017 21:36:22 +0200
Subject: server: Send _push ping every 60s

---
 main.c    | 12 ++++++++++--
 runloop.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 runloop.h |  4 +++-
 3 files changed, 64 insertions(+), 7 deletions(-)

diff --git a/main.c b/main.c
index 1a0bd10..82d875b 100644
--- a/main.c
+++ b/main.c
@@ -10,6 +10,7 @@
 #include "command.h"
 #include "conn_data.h"
 #include "db.h"
+#include "net.h"
 #include "runloop.h"
 #include "user_data.h"
 
@@ -111,7 +112,7 @@ static bool server_socket_callback(int fd){
 	do sock=accept(fd,NULL,NULL);
 	while(sock<0&&errno==EINTR);
 	if(sock<0)die_perror("accept");
-	runloop_add_fd(sock,client_socket_callback);
+	runloop_add_fd(sock,client_socket_callback,true);
 
 	struct hash_item *item=malloc(1,struct hash_item);
 	conn_data_init(&item->cd,sock);
@@ -121,6 +122,11 @@ static bool server_socket_callback(int fd){
 	return false;
 }
 
+static bool timeout_callback(int fd){
+	net_send_raw_text(fd,"_push ping\n",11);
+	return false;  // We aren't going to get closure info from a send()
+}
+
 #ifndef __APPLE__
 void srandomdev(void){
 	FILE *f=fopen("/dev/urandom","r");
@@ -139,7 +145,9 @@ int main(void){
 	db_init();
 	int sock=create_server_socket();
 	printf("Listening on port %d\n",PORT);
-	runloop_add_fd(sock,server_socket_callback);
+	runloop_set_timeout(60*1000000,timeout_callback);
+	runloop_add_fd(sock,server_socket_callback,false);
 	runloop_run();
+	printf("Runloop empty, shutting down\n");
 	db_close();
 }
diff --git a/runloop.c b/runloop.c
index 30f28b2..119bf01 100644
--- a/runloop.c
+++ b/runloop.c
@@ -1,17 +1,22 @@
 #include <string.h>
 #include <errno.h>
 #include <sys/select.h>
+#include <sys/time.h>
 #include "runloop.h"
 
 
 struct fd_list_item{
 	int fd;
 	runloop_callback *func;
+	i64 last_activity;  // -1 if timeout is not enabled
 };
 
 static struct fd_list_item *fd_list;
 static size_t fd_list_len,fd_list_cap;
 
+static i64 timeout_usecs=0;
+static runloop_callback *timeout_callback=NULL;
+
 __attribute__((constructor))
 static void constructor(void){
 	fd_list_cap=16;
@@ -20,32 +25,74 @@ static void constructor(void){
 }
 
 
-void runloop_add_fd(int fd,runloop_callback *func){
+static i64 make_timestamp(void){
+	struct timeval tv;
+	gettimeofday(&tv,NULL);
+	return (i64)tv.tv_sec*1000000+tv.tv_usec;
+}
+
+void runloop_set_timeout(i64 usecs,runloop_callback *cb){
+	timeout_usecs=usecs;
+	timeout_callback=cb;
+}
+
+void runloop_add_fd(int fd,runloop_callback *func,bool use_timeout){
 	if(fd_list_len==fd_list_cap){
 		fd_list_cap*=2;
 		fd_list=realloc(fd_list,fd_list_cap,struct fd_list_item);
 	}
 	fd_list[fd_list_len].fd=fd;
 	fd_list[fd_list_len].func=func;
+	fd_list[fd_list_len].last_activity=use_timeout ? make_timestamp() : -1;
 	fd_list_len++;
 }
 
 void runloop_run(void){
-	while(true){
+	while(fd_list_len>0){
 		fd_set inset;
 		FD_ZERO(&inset);
 		int maxfd=-1;
+		i64 oldest_timestamp=-1;
+		int oldest_at=-1;
 		for(size_t i=0;i<fd_list_len;i++){
 			FD_SET(fd_list[i].fd,&inset);
 			if(fd_list[i].fd>maxfd)maxfd=fd_list[i].fd;
+			if(fd_list[i].last_activity!=-1&&
+					(oldest_timestamp==-1||fd_list[i].last_activity<oldest_timestamp)){
+				oldest_timestamp=fd_list[i].last_activity;
+				oldest_at=i;
+			}
 		}
-		int ret=select(maxfd+1,&inset,NULL,NULL,NULL);
-		if(ret<=0){
+
+		struct timeval tv={.tv_sec=0,.tv_usec=0};
+		struct timeval *tv_ptr=NULL;
+		if(timeout_usecs>0&&timeout_callback!=NULL&&oldest_timestamp!=-1){
+			i64 chosen_timeout=timeout_usecs-(make_timestamp()-oldest_timestamp);
+			if(chosen_timeout<0)chosen_timeout=0;
+			tv.tv_sec=chosen_timeout/1000000;
+			tv.tv_usec=chosen_timeout%1000000;
+			tv_ptr=&tv;
+		}
+		int ret=select(maxfd+1,&inset,NULL,NULL,tv_ptr);
+		if(ret==0){
+			fd_list[oldest_at].last_activity=make_timestamp();
+			if(timeout_callback(fd_list[oldest_at].fd)){
+				memmove(fd_list+oldest_at,fd_list+oldest_at+1,
+				        (fd_list_len-oldest_at-1)*sizeof(struct fd_list_item));
+				fd_list_len--;
+			}
+			continue;
+		}
+		if(ret<0){
 			if(errno==EINTR)continue;
 			die_perror("select");
 		}
+
 		for(size_t i=0;i<fd_list_len;i++){
 			if(FD_ISSET(fd_list[i].fd,&inset)){
+				if(fd_list[i].last_activity!=-1){
+					fd_list[i].last_activity=make_timestamp();
+				}
 				if(fd_list[i].func(fd_list[i].fd)){
 					memmove(fd_list+i,fd_list+i+1,(fd_list_len-i-1)*sizeof(struct fd_list_item));
 					i--;
diff --git a/runloop.h b/runloop.h
index fc1f7e8..ae0639b 100644
--- a/runloop.h
+++ b/runloop.h
@@ -6,5 +6,7 @@
 // Return true to remove fd from runloop
 typedef bool runloop_callback(int fd);
 
-void runloop_add_fd(int fd,runloop_callback *func);
+void runloop_set_timeout(i64 usecs,runloop_callback *timeout_callback);
+
+void runloop_add_fd(int fd,runloop_callback *func,bool use_timeout);
 void runloop_run(void);  // Returns when empty
-- 
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