server: Implement get_message

3 files changed, 85 insertions, 12 deletions

diff --git a/command.c b/command.c
index ba8727e..ca70d76 100644
--- a/command.c
+++ b/command.c
@@ -257,9 +257,13 @@ static struct cmd_retval cmd_send(struct conn_data *data,const char *tag,const c
 		net_send_error(data->fd,tag,"Not in that room");
 		return RET_OK;
 	}
-	if(replyid>=0&&!db_message_exists(roomid,replyid)){
-		net_send_error(data->fd,tag,"Replied-to message not found");
-		return RET_OK;
+	if(replyid>=0){
+		struct db_message msg=db_get_message(replyid);
+		if(msg.msgid==-1){
+			net_send_error(data->fd,tag,"Replied-to message not found");
+			return RET_OK;
+		}
+		db_nullify_message(msg);
 	}
 
 	i64 timestamp=make_timestamp();
@@ -361,6 +365,48 @@ static struct cmd_retval cmd_history_before(struct conn_data *data,const char *t
 	return history_cmd_helper(data,tag,args,"history_before",beforeid);
 }
 
+static struct cmd_retval cmd_get_message(struct conn_data *data, const char *tag, const char **args) {
+	i64 msgid;
+	if (!parse_i64(args[0], &msgid)) {
+		debug("Connection fd=%d sent an invalid number for 'get_message': '%s'",
+				data->fd, args[0]);
+		return RET_CLOSE(true);
+	}
+
+	if (data->userid == -1) {
+		net_send_error(data->fd, tag, "Not logged in");
+		return RET_OK;
+	}
+
+	struct db_message msg = db_get_message(msgid);
+	if (msg.msgid == -1) {
+		net_send_error(data->fd, tag, "Message not found");
+		return RET_OK;
+	}
+
+	if (!db_is_member(msg.roomid, data->userid)) {
+		db_nullify_message(msg);
+		// Don't disclose that the message actually exists elsewhere
+		net_send_error(data->fd, tag, "Message not found");
+		return RET_OK;
+	}
+
+	char *roomname = db_get_roomname(msg.roomid);
+	char *username = db_get_username(msg.userid);
+
+	char *buf = NULL;
+	i64 len = asprintf(&buf, "%s message %s %s %" PRIi64 " %" PRIi64 " %" PRIi64 " %s\n",
+			tag, roomname, username, msg.timestamp, msg.msgid, msg.replyid, msg.message);
+	free(roomname);
+	free(username);
+
+	bool closed = net_send_raw_text(data->fd, buf, len);
+	free(buf);
+
+	db_nullify_message(msg);
+	return RET_CLOSE(closed);
+}
+
 static struct cmd_retval cmd_ping(struct conn_data *data,const char *tag,const char **args){
 	(void)args;
 	return RET_CLOSE(net_send_pong(data->fd,tag));
@@ -419,8 +465,8 @@ struct cmd_info{
 
 // Use CommandHash.hs to re-generate this perfect hash function for a different
 // list of commands.
-#define COMMAND_HASH_MODULUS 31
-#define COMMAND_HASH(cmd0, len) ((cmd0 + 6 * len) % COMMAND_HASH_MODULUS)
+#define COMMAND_HASH_MODULUS 34
+#define COMMAND_HASH(cmd0, len) ((4 * cmd0 + 7 * len) % COMMAND_HASH_MODULUS)
 
 #define COMMAND_ENTRY(cmd0, cmd, nargs, longlast, handler) \
 	[COMMAND_HASH(cmd0, strlen(cmd))] = {cmd, nargs, longlast, handler}
@@ -439,6 +485,7 @@ static const struct cmd_info commands[COMMAND_HASH_MODULUS] = {
 	COMMAND_ENTRY('s', "send", 3, true, cmd_send),
 	COMMAND_ENTRY('h', "history", 2, false, cmd_history),
 	COMMAND_ENTRY('h', "history_before", 3, false, cmd_history_before),
+	COMMAND_ENTRY('g', "get_message", 1, false, cmd_get_message),
 	COMMAND_ENTRY('p', "ping", 0, false, cmd_ping),
 	COMMAND_ENTRY('i', "is_online", 1, false, cmd_is_online),
 	COMMAND_ENTRY('f', "firebase_token", 1, false, cmd_firebase_token),
diff --git a/db.c b/db.c
index 416b9d3..d94b13c 100644
--- a/db.c
+++ b/db.c
@@ -460,16 +460,37 @@ struct db_message_list db_get_messages_before(i64 roomid,i64 count,i64 beforeid)
 	return ml;
 }
 
-bool db_message_exists(i64 roomid, i64 msgid) {
+struct db_message db_get_message(i64 msgid) {
 	sqlite3_stmt *stmt;
 	SQLITE(prepare_v2, database,
-			"select id from Messages where id = ? and room = ?",
+			"select room, user, time, reply, message "
+			"from Messages where id = ?",
 		-1, &stmt, NULL);
 	SQLITE(bind_int64, stmt, 1, msgid);
-	SQLITE(bind_int64, stmt, 2, roomid);
-	bool success = sqlite3_step(stmt) == SQLITE_ROW;
+
+	struct db_message msg;
+	if (sqlite3_step(stmt) == SQLITE_ROW) {
+		msg.msgid = msgid;
+		msg.roomid = sqlite3_column_int64(stmt,0);
+		msg.userid = sqlite3_column_int64(stmt,1);
+		msg.timestamp = sqlite3_column_int64(stmt,2);
+		if (sqlite3_column_type(stmt, 3) == SQLITE_INTEGER) {
+			msg.replyid = sqlite3_column_int64(stmt, 3);
+		} else {
+			msg.replyid = -1;  // NULL, not a reply
+		}
+		msg.message = strdup((const char*)sqlite3_column_text(stmt, 4));
+	} else {
+		msg.msgid = -1;
+		msg.roomid = -1;
+		msg.userid = -1;
+		msg.timestamp = -1;
+		msg.replyid = -1;
+		msg.message = NULL;
+	}
+
 	SQLITE(finalize, stmt);
-	return success;
+	return msg;
 }
 
 
@@ -493,9 +514,13 @@ void db_nullify_user_list(struct db_user_list ul){
 	ul.list=NULL;
 }
 
+void db_nullify_message(struct db_message msg){
+	if(msg.message)free(msg.message);
+}
+
 void db_nullify_message_list(struct db_message_list ml){
 	for(i64 i=0;i<ml.count;i++){
-		free(ml.list[i].message);
+		db_nullify_message(ml.list[i]);
 	}
 	if(ml.list)free(ml.list);
 	ml.list=NULL;
diff --git a/db.h b/db.h
index 13df899..73d275a 100644
--- a/db.h
+++ b/db.h
@@ -64,10 +64,11 @@ i64 db_create_message(i64 roomid,i64 userid,i64 timestamp,i64 replyid,const char
 struct db_message_list db_get_messages(i64 roomid,i64 count);  // gets latest `count` messages in rev. chron. order
 // if beforeid<0, same as db_get_messages
 struct db_message_list db_get_messages_before(i64 roomid,i64 count,i64 beforeid);
-bool db_message_exists(i64 roomid,i64 msgid);
+struct db_message db_get_message(i64 msgid);  // returns {msgid=-1} if nonexistent
 
 void db_nullify_name_id(struct db_name_id ni);
 void db_nullify_room_list(struct db_room_list rl);
 void db_nullify_user_list(struct db_user_list ul);
+void db_nullify_message(struct db_message ml);
 void db_nullify_message_list(struct db_message_list ml);
 void db_nullify_strings_list(struct db_strings_list sl);