server: Get history before id

3 files changed, 53 insertions, 12 deletions

diff --git a/command.c b/command.c
index 3d406e1..e4d75d3 100644
--- a/command.c
+++ b/command.c
@@ -1,6 +1,7 @@
 #define _GNU_SOURCE
 #include <stdio.h>
 #include <string.h>
+#include <limits.h>
 #include <errno.h>
 #include <sys/time.h>
 #include <sys/socket.h>
@@ -238,11 +239,14 @@ static bool cmd_send(struct conn_data *data,const char *tag,const char **args){
 	return closed;
 }
 
-static bool cmd_history(struct conn_data *data,const char *tag,const char **args){
+static bool history_cmd_helper(
+		struct conn_data *data,const char *tag,const char **args,
+		const char *cmdname,i64 beforeid){
 	char *endp;
 	i64 nrequested=strtoll(args[1],&endp,10);
 	if(args[1][0]=='\0'||*endp!='\0'||nrequested<0){
-		debug("Connection fd=%d sent an invalid number for 'history': '%s'",data->fd,args[1]);
+		debug("Connection fd=%d sent an invalid number for '%s': '%s'",
+				data->fd,cmdname,args[1]);
 		return true;
 	}
 
@@ -261,7 +265,7 @@ static bool cmd_history(struct conn_data *data,const char *tag,const char **args
 		return false;
 	}
 
-	struct db_message_list ml=db_get_messages(roomid,nrequested);
+	struct db_message_list ml=db_get_messages_before(roomid,nrequested,beforeid);
 	char *buf=NULL;
 	i64 len=asprintf(&buf,"%s history %" PRIi64 "\n",tag,ml.count);
 	bool closed=net_send_raw_text(data->fd,buf,len);
@@ -286,6 +290,23 @@ static bool cmd_history(struct conn_data *data,const char *tag,const char **args
 	return closed;
 }
 
+static bool cmd_history(struct conn_data *data,const char *tag,const char **args){
+	return history_cmd_helper(data,tag,args,"history",-1);
+}
+
+static bool cmd_history_before(struct conn_data *data,const char *tag,const char **args){
+	char *endp;
+	i64 beforeid=strtoll(args[2],&endp,10);
+	if(args[2][0]=='\0'||*endp!='\0'){
+		debug("Connection fd=%d sent an invalid id for 'history_before': '%s'",
+				data->fd,args[2]);
+		return true;
+	}
+	if(beforeid<0)beforeid=INT64_MAX;
+
+	return history_cmd_helper(data,tag,args,"history_before",beforeid);
+}
+
 static bool cmd_ping(struct conn_data *data,const char *tag,const char **args){
 	(void)args;
 	return net_send_pong(data->fd,tag);
@@ -353,6 +374,7 @@ static const struct cmd_info commands[]={
 	{"invite",2,false,cmd_invite},
 	{"send",2,true,cmd_send},
 	{"history",2,false,cmd_history},
+	{"history_before",3,false,cmd_history_before},
 	{"ping",0,false,cmd_ping},
 	{"is_online",1,false,cmd_is_online},
 	{"firebase_token",1,false,cmd_firebase_token},
diff --git a/db.c b/db.c
index a193b24..f48148e 100644
--- a/db.c
+++ b/db.c
@@ -304,18 +304,35 @@ void db_create_message(i64 roomid,i64 userid,i64 timestamp,const char *message){
 }
 
 struct db_message_list db_get_messages(i64 roomid,i64 count){
+	return db_get_messages_before(roomid,count,-1);
+}
+
+struct db_message_list db_get_messages_before(i64 roomid,i64 count,i64 beforeid){
 	assert(count>=0);
 
 	sqlite3_stmt *stmt;
-	SQLITE(prepare_v2,database,
-			"select id, user, time, message "
-			"from Messages "
-			"where room = ? "
-			"order by time desc "
-			"limit ?"
-		,-1,&stmt,NULL);
-	SQLITE(bind_int64,stmt,1,roomid);
-	SQLITE(bind_int64,stmt,2,count);
+	if(beforeid<0){
+		SQLITE(prepare_v2,database,
+				"select id, user, time, message "
+				"from Messages "
+				"where room = ? "
+				"order by time desc "
+				"limit ?"
+			,-1,&stmt,NULL);
+		SQLITE(bind_int64,stmt,1,roomid);
+		SQLITE(bind_int64,stmt,2,count);
+	} else {
+		SQLITE(prepare_v2,database,
+				"select id, user, time, message "
+				"from Messages "
+				"where room = ? and time < (select time from Messages where id = ?) "
+				"order by time desc "
+				"limit ?"
+			,-1,&stmt,NULL);
+		SQLITE(bind_int64,stmt,1,roomid);
+		SQLITE(bind_int64,stmt,2,beforeid);
+		SQLITE(bind_int64,stmt,3,count);
+	}
 
 	struct db_message_list ml;
 	i64 cap=count;
diff --git a/db.h b/db.h
index 6bc2b62..6b1d92b 100644
--- a/db.h
+++ b/db.h
@@ -60,6 +60,8 @@ bool db_delete_token(i64 userid,const char *token);
 
 void db_create_message(i64 roomid,i64 userid,i64 timestamp,const char *message);
 struct db_message_list db_get_messages(i64 roomid,i64 count);  // gets latest `count` messages
+// if beforeid<0, same as db_get_messages
+struct db_message_list db_get_messages_before(i64 roomid,i64 count,i64 beforeid);
 
 void db_nullify_name_id(struct db_name_id ni);
 void db_nullify_room_list(struct db_room_list rl);