threaded_network_chat/chat.cc

#include <algorithm>
#include <cstdio>
#include <fstream>
#include <iterator>
#include <netinet/in.h>
#include <pthread.h>

#include <curses.h>
#include <string.h>
#include <sys/select.h>
#include <sys/time.h>
#include <unistd.h>

#include "chat.h"

void
clear_rows(int s, int e)
{
	/* preserve cursor location */
	int x_bef;
	int y_bef;

	getyx(stdscr, y_bef, x_bef);

	for (int i = s; i < e; i++) {
		move(i, 0);
		clrtoeol();
	}

	move(y_bef, x_bef);
}

int
file_disp(std::string p, int lnstart, int lncount)
{
	std::ifstream f(p);

	if (!f)
		return 1;

	int i = 0;
	int ln_no = 0;
	std::string ln;

	clear_rows(0, lncount + 1); /* clear chat window */

	while (getline(f, ln) && i <= ln_no + lnstart + 1) {
		if (i >= lnstart) {
			move(ln_no, 0);
			printw("%s", ln.c_str());
			ln_no++;
		}
		i++;
	}

	move(CURSOR_DEFAULT_POSITION_Y, CURSOR_DEFAULT_POSITION_X);
	refresh();
	return 0;
}

int
count_lines(std::string p)
{
	int c = 0;

	std::ifstream f(p);
	if (!f)
		return c;

	/* Apparently this is the most efficient way to count all lines in a file. How revolting! */
	c = std::count(std::istreambuf_iterator<char>(f), std::istreambuf_iterator<char>(), '\n');

	return c;
}

void *
await_client(void *a)
{
	wclient_args_t *args = static_cast<wclient_args_t *>(a);

	socket_descriptor_client = accept(socket_descriptor_server, (sockaddr *)&args->new_addr, &args->new_addr_siz);

	if (socket_descriptor_client >= 0) {
		log_append(log_path, "client connected");

		if (count_lines(log_path) > LOG_LENGTH)
			line_position++;

		file_disp(log_path, line_position, LOG_LENGTH);
	}

	delete args;

	return client_poll();
}

void *
client_poll(void)
{
	char msg[1024];
	for (;;) {
		/* listen for msg from client */
		memset(&msg, 0, sizeof(msg)); /* clear buf */
		bytes_read += recv(socket_descriptor_client, (char *)&msg, sizeof(msg), 0);
		log_append(log_path, msg);

		if (count_lines(log_path) > LOG_LENGTH)
			line_position++;

		file_disp(log_path, line_position, LOG_LENGTH);
	}

	return nullptr;
}

void
server_start(int port)
{
	auto *a = new wclient_args_t{};
	sockaddr_in srv_addr;
	sockaddr_in newsock;
	socklen_t newsock_siz = sizeof(newsock);
	int bstat;
	int rc;

	/* set up socket and connection tools */
	bzero((char *)&srv_addr, sizeof(srv_addr));
	srv_addr.sin_family = AF_INET;
	srv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
	srv_addr.sin_port = htons(port);

	/* open stream-oriented socket w inet addr and track sock descriptor */
	socket_descriptor_server = socket(AF_INET, SOCK_STREAM, 0);
	if (socket_descriptor_server < 0)
		goto panic_if_no_server_sock;

	/* bind sock to its local addr */
	bstat = bind(socket_descriptor_server, (struct sockaddr *)&srv_addr, sizeof(srv_addr));
	if (bstat < 0)
		goto panic_if_no_server_sock;

	log_append(log_path, "Waiting for a client to connect...");

	/* listen for up to 5 simultaneous requests */
	listen(socket_descriptor_server, 5);
	a->new_addr = newsock;
	a->new_addr_siz = newsock_siz;

	rc = pthread_create(&client_wait_thread, nullptr, await_client, a);

	pthread_detach(client_wait_thread);

	log_append(log_path, "Server started successfully.");

	gettimeofday(&time_start, NULL);

	return;

panic_if_no_server_sock:
	endwin();
	fprintf(stderr, "Fatal: Could not establish server socket!\n");
	exit(1);
}

void
server_stop(void)
{
	long e = time_end.tv_sec - time_start.tv_sec;

	gettimeofday(&time_end, NULL);
	close(socket_descriptor_server);

	/* Don't just die silently */
	puts("********Session********");
	printf("Bytes written: %i\nBytes Read: %i\n", bytes_written, bytes_read);
	printf("Elapsed time: %ld\n secs\n", e);
	puts("Connection closed...");
}

void
client_stop(void)
{
	long e = time_end.tv_sec - time_start.tv_sec;

	gettimeofday(&time_end, NULL);
	close(socket_descriptor_client);
	puts("********Session********");
	printf("Bytes written: %i\nBytes read: %i\n", bytes_written, bytes_read);
	printf("Elapsed time: %ld\n secs\n", e);
	puts("Connection closed...");
}

void *
server_poll(void *args)
{
	wclient_args_t *a = static_cast<wclient_args_t*>(args);
	int sock_desc = (int)a->aux;
	char msg[1024];

	for (;;) {
		memset(&msg, 0, sizeof(msg));
		bytes_read += recv(sock_desc, (char*)&msg, sizeof(msg), 0);

		log_append(log_path, msg);

		if (count_lines(log_path) > LOG_LENGTH)
			line_position++;

		file_disp(log_path, line_position, LOG_LENGTH);
	}
}