Switch completely to Go and Gio UI

The properties of the Go language, standard library and the Gio UI
library are well suited for this project. The existing experimental Go
code exceeds the GTK4 and SDL attempts by far with respect to quality
and code simplicity.

13 files changed, 2 insertions, 567 deletions

diff --git a/Makefile b/Makefile
deleted file mode 100644
index 2ffa1b8..0000000
--- a/Makefile
+++ /dev/null
@@ -1,40 +0,0 @@
-CC=gcc
-CFLAGS=-g -I. -lSDL2
-SRC:=$(shell find ./ -maxdepth 1 -type f -regex ".*\.c" -not -name "main.c")
-OBJ:=$(patsubst ./%.c,build/%.o,$(SRC))
-_TESTS:=$(shell find ./tests/ -maxdepth 1 -type f -regex ".*\.c")
-TESTS:=$(patsubst ./%.c,build/%,$(_TESTS))
-
-LIMOX=build/limox
-GRAPHICS=build/icon.png build/icon.pdf
-DOCS=build/docs/README.pdf build/docs/ROADMAP.pdf
-
-all: build $(OBJ) $(TESTS) $(LIMOX) $(DOCS) $(GRAPHICS)
-
-build:
-	mkdir -p build/tests
-	mkdir -p build/docs
-
-$(LIMOX): $(OBJ) build/main.o
-	$(CC) -o $@ $^ $(CFLAGS)
-
-build/%.o: %.c
-	$(CC) -c -o $@ $< $(CFLAGS)
-
-build/%.png: %.svg
-	inkscape $< -o $@ -w 256 -h 256
-
-build/%.pdf: %.svg
-	inkscape $< -o $@ -w 256 -h 256
-
-build/docs/%.pdf: %.md $(GRAPHICS)
-	pandoc -o $@ $<
-
-build/tests/%: tests/%.c $(OBJ)
-	$(CC) -o $@ $< $(OBJ) $(CFLAGS)
-	$@
-
-.PHONY: clean
-
-clean:
-	rm -rf build
diff --git a/README.md b/README.md
index 7b13320..cffa779 100644
--- a/README.md
+++ b/README.md
@@ -7,40 +7,7 @@ usable on mobile linux devices like smartphones or tablets.
 
 ![LimoX icon](build/icon.pdf)
 
-Also mind the `ROADMAP` file, the [project page][1] and my [packaging
-repository][2] for Arch Linux with support for LimoX. A nice reference which
-helps me a lot is [Beej's Guide to Network Programming][3] aswell as [Gigi's
-SDL2 tutorial][5] and the [SDL2 documentation][4].
-
-
-## Building and dependencies
-
-Install these build dependencies:
-
-- GNU coreutils
-- GNU make
-- gcc
-- pandoc
-- texlive-core
-- inkscape
-
-Install these runtime dependencies:
-
-- sdl2
-
-Just run these commands to build, test and run:
-
-```
-make all
-./build/limox
-```
-
-Run `make clean` to clean the build folder. You can get a help page by running
-`./build/limox -h`.
+Also mind the `ROADMAP` file and the [project page][1].
 
 
 [1]: https://xengineering.eu/git/limox
-[2]: https://xengineering.eu/git/pkgbuilds
-[3]: https://www.beej.us/guide/bgnet/html/
-[4]: https://wiki.libsdl.org/SDL2/FrontPage
-[5]: https://gigi.nullneuron.net/gigilabs/writing/sdl2-tutorials/
diff --git a/ROADMAP.md b/ROADMAP.md
index d26aab2..cec6e4c 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -2,8 +2,7 @@
 
 # Roadmap
 
-- [x] develop minimal viable product with GTK4 (branch `legacy/gtk4-libstrophe`)
-- [ ] develop minimal viable product with SDL2
+- [ ] develop minimal viable product
 - [ ] implement XMPP core client ([compliance suite 2022][1])
 	- [ ] RFC 6120: XMPP Core
 	- [ ] RFC 7590: TLS for XMPP
diff --git a/go/go.mod b/go.mod
index de2e3d7..de2e3d7 100644
--- a/go/go.mod
+++ b/go.mod
diff --git a/go/go.sum b/go.sum
index 4d42bf4..4d42bf4 100644
--- a/go/go.sum
+++ b/go.sum
diff --git a/gui.c b/gui.c
deleted file mode 100644
index 12f8f47..0000000
--- a/gui.c
+++ /dev/null
@@ -1,115 +0,0 @@
-/*
- * LimoX - The Linux on mobile XMPP chat client
- * Copyright (C) 2022  xengineering
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-
-#include <SDL2/SDL.h>
-#include <stdbool.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#include "xmpp.h"
-
-
-struct GuiContext {
-	bool quit;
-	SDL_Event event;
-	SDL_Window* window;
-	SDL_Renderer* renderer;
-	SDL_Texture* texture;
-	uint32_t* pixels;
-	int xmpp_fd;
-};
-
-
-struct GuiContext *init() {
-	struct GuiContext *ctx = malloc(sizeof(struct GuiContext));
-
-	ctx->quit = false;
-	ctx->xmpp_fd = -1;
-
-	ctx->pixels = malloc(sizeof(uint32_t) * 640 * 480);
-	memset(ctx->pixels, 255, 640 * 480 * sizeof(uint32_t));
-
-	SDL_Init(SDL_INIT_VIDEO);
-
-	return ctx;
-}
-
-void deinit(struct GuiContext *ctx) {
-
-	// TODO this seems to end in memory access errors but ... why?
-	//SDL_DestroyTexture(texture);
-	//SDL_DestroyRenderer(renderer);
-
-	SDL_Quit();
-
-	free(ctx->pixels);
-	free(ctx);
-}
-
-bool create_window(struct GuiContext *ctx) {
-
-	ctx->window = SDL_CreateWindow("LimoX",
-	    SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 640, 480,
-	    SDL_WINDOW_RESIZABLE
-	);
-
-	ctx->renderer = SDL_CreateRenderer(ctx->window, -1, 0);
-	ctx->texture = SDL_CreateTexture(ctx->renderer, SDL_PIXELFORMAT_ARGB8888,
-	                                 SDL_TEXTUREACCESS_STATIC, 640, 480);
-
-	return ctx->window != NULL;
-}
-
-void gui_run(void) {
-
-	struct GuiContext *ctx = init();
-
-	fprintf(stderr, "SDL2 video driver: %s\n", SDL_GetCurrentVideoDriver());
-
-	if (!create_window(ctx)) {
-		fprintf(stderr, "Failed to create SDL2 window!\n");
-		return;
-	}
-
-	while (!ctx->quit) {
-		SDL_UpdateTexture(ctx->texture, NULL, ctx->pixels, 640 * sizeof(uint32_t));
-		SDL_WaitEvent(&ctx->event);
-		switch (ctx->event.type) {
-		case SDL_QUIT:
-			ctx->quit = true;
-			break;
-		case SDL_MOUSEBUTTONDOWN:
-			if (ctx->xmpp_fd == -1) {
-				ctx->xmpp_fd = xmpp_connect();
-			} else {
-				close(ctx->xmpp_fd);
-				ctx->xmpp_fd = -1;
-				printf("Closed XMPP connection.\n");
-			}
-			break;
-		}
-		SDL_RenderClear(ctx->renderer);
-		SDL_RenderCopy(ctx->renderer, ctx->texture, NULL, NULL);
-		SDL_RenderPresent(ctx->renderer);
-	}
-
-	SDL_DestroyWindow(ctx->window);
-	deinit(ctx);
-
-}
diff --git a/gui.h b/gui.h
deleted file mode 100644
index 331ad2c..0000000
--- a/gui.h
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * LimoX - The Linux on mobile XMPP chat client
- * Copyright (C) 2022  xengineering
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-
-void gui_run(void);
diff --git a/main.c b/main.c
deleted file mode 100644
index bdce11b..0000000
--- a/main.c
+++ /dev/null
@@ -1,85 +0,0 @@
-/*
- * LimoX - The Linux on mobile XMPP chat client
- * Copyright (C) 2022  xengineering
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-
-#include <stdbool.h>
-#include <stdio.h>
-#include <getopt.h>
-
-#include "gui.h"
-
-
-/*
- * Configuration struct for all options
- */
-struct Options {
-	bool unknown;
-	bool help;
-};
-
-
-/*
- * Parse command line arguments
- */
-static void get_opts(struct Options *opts, int argc, char* argv[])
-{
-	opts->unknown = false;
-	opts->help = false;
-
-	int c;
-	while ((c=getopt(argc, argv, "h")) != -1) {
-
-		switch (c) {
-			case 'h':
-				opts->help = true;
-				break;
-			default:
-				opts->unknown = true;
-		}
-	}
-}
-
-/*
- * Print help page to command line
- */
-static void print_help(void)
-{
-	printf(
-		"The Linux on mobile XMPP (LimoX) client.\n"
-		"\n"
-		"Usage: limox [-h]\n"
-		"\n"
-		"Options:\n"
-		"          -h        print help page\n"
-	);
-}
-
-/*
- * Run control flow of the application
- */
-int main(int argc, char* argv[])
-{
-	struct Options opts;
-	get_opts(&opts, argc, argv);
-
-	if (opts.unknown || opts.help) {
-		print_help();
-	} else {
-		gui_run();
-	}
-}
diff --git a/go/main.go b/main.go
index 2803e68..2803e68 100644
--- a/go/main.go
+++ b/main.go
diff --git a/tests/get_domainpart.c b/tests/get_domainpart.c
deleted file mode 100644
index 6601330..0000000
--- a/tests/get_domainpart.c
+++ /dev/null
@@ -1,40 +0,0 @@
-/*
- * LimoX - The Linux on mobile XMPP chat client
- * Copyright (C) 2022  xengineering
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-
-#include <string.h>
-#include <stdio.h>
-
-#include "xmpp.h"
-
-
-int main(void)
-{
-	char *input = "test@example.org/3f";
-	const char *expected = "example.org";
-
-	char *result = get_domainpart(input);
-
-	if (strcmp(result, expected) == 0) {
-		printf("Unit test passed - \033[;32mok\033[0m\n");
-		return 0;
-	} else {
-		printf("'%s' != '%s' - \033[;31mfailed\033[0m\n", result, expected);
-		return 1;
-	}
-}
diff --git a/tools/lint.sh b/tools/lint.sh
deleted file mode 100755
index 5264112..0000000
--- a/tools/lint.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/bin/sh
-
-
-if ! command -v splint 2> /dev/null
-then
-	echo "Please install splint (http://splint.org/)!"
-	exit 1
-fi
-
-find . -type f -iname '*.c' | xargs splint
diff --git a/xmpp.c b/xmpp.c
deleted file mode 100644
index 18bb6c5..0000000
--- a/xmpp.c
+++ /dev/null
@@ -1,200 +0,0 @@
-/*
- * LimoX - The Linux on mobile XMPP chat client
- * Copyright (C) 2022  xengineering
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-
-#define _GNU_SOURCE
-#include <stdlib.h>
-#include <stdio.h>
-#include <errno.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <arpa/inet.h>
-#include <netdb.h>
-#include <stdbool.h>
-
-
-/*
- * Get the domainpart of the Jabber ID (JID)
- *
- * See https://datatracker.ietf.org/doc/html/rfc7622#section-3.2 for details.
- */
-char *get_domainpart(char *jid)
-{
-	int start = 0;           // inclusive index
-	int stop = strlen(jid);  // exclusive index
-
-	for(int i=0; i<strlen(jid); i++) {
-		if (jid[i] == '/') {
-			stop = i;
-			break;
-		}
-	}
-
-	for(int i=0; i<strlen(jid); i++) {
-		if (jid[i] == '@') {
-			start = i + 1;
-			break;
-		}
-	}
-
-	char *retval = (char *)malloc((stop-start+1) * sizeof(char));
-	memcpy(retval, jid+start, (stop-start) * sizeof(char));
-	retval[stop] = '\0';
-
-	return retval;
-}
-
-/*
- * Return the preferred struct addrinfo * or NULL
- *
- * This handles DNS resolution. It returns the first valid addrinfo which is
- * returned by getaddrinfo. Mind that the addrinfo could use IPv6 instead of
- * IPv4.
- *
- * FIXME this just takes the first received IPv4 address (by far not compliant
- *       to RFC 6120!)
- * FIXME This function contains a memory leak! Free the linked list servinfo!
- */
-struct addrinfo *resolve_dns(char *domain)
-{
-	struct addrinfo hints;
-	struct addrinfo *servinfo;
-	void *addr;
-	char ipstr[INET6_ADDRSTRLEN];
-	memset(&hints, 0, sizeof hints);
-	hints.ai_family = AF_UNSPEC;
-	hints.ai_socktype = SOCK_STREAM;
-	if (getaddrinfo(domain, "xmpp-client", &hints, &servinfo) != 0) {
-		printf("Failed to resolve hostname '%s'.\n", domain);
-		return NULL;
-	}
-	struct addrinfo *p;
-	for(p=servinfo; p!=NULL; p=p->ai_next) {
-		if (p->ai_family == AF_INET) {
-			struct sockaddr_in *ipv4 = (struct sockaddr_in *)p->ai_addr;
-			addr = &(ipv4->sin_addr);
-			inet_ntop(p->ai_family, addr, ipstr, sizeof ipstr);
-			printf("Got compatible IPv4 address %s from DNS.\n", ipstr);
-			return p;
-		} else if (p->ai_family == AF_INET6) {
-			printf("Ignored IPv6 DNS entry which is not supported.\n");
-		} else {
-			printf("Ignored unknown addrinfo address type.\n");
-		}
-	}
-	printf("No suitable IP address found via DNS!\n");
-	return NULL;
-}
-
-/*
- * Start XMPP stream via the given socket filedescriptor
- *
- * Returns 0 in case of success and -1 otherwise.
- */
-int start_stream(int sock_fd, char *jid, char *domainpart)
-{
-	const char *tmpl = "<stream:stream\
- from='%s'\
- to='%s'\
- version='1.0'\
- xml:lang='en'\
- xmlns='jabber:client'\
- xmlns:stream='http://etherx.jabber.org/streams'>";
-
-	char *msg;
-	asprintf(&msg, tmpl, jid, domainpart);
-	int len = strlen(msg);
-
-	int sent = send(sock_fd, msg, len, 0);
-	if (sent == len) {
-		printf(">>> %s\n", msg);
-		return 0;
-	} else if (sent == 0) {
-		printf("Failed to send any bytes to server!\n");
-		return -1;
-	} else {
-		printf("Could just send %d bytes of %d bytes to server!\n", sent, len);
-		return -1;
-	}
-}
-
-/*
- * Get JID and password and return true on success
- */
-bool get_credentials(char **jid, char **pwd)
-{
-	if (getenv("LIMOX_USER") == NULL || getenv("LIMOX_PWD") == NULL) {
-		printf("Failed to connect.\n");
-		printf("Please set the LIMOX_USER and LIMOX_PWD shell variables.\n");
-		return false;
-	}
-
-	*jid = getenv("LIMOX_USER");
-	*pwd = getenv("LIMOX_PWD");
-
-	return true;
-}
-
-/*
- * Initialize the network connection to the XMPP server and return socket fd
- *
- * TODO: Error handling is missing.
- */
-int xmpp_connect(void)
-{
-	printf("net_init()\n");
-
-	int sock = -1;
-
-	char *jid;
-	char *pwd;
-	if (!get_credentials(&jid, &pwd)) {
-		return sock;
-	}
-	printf("Trying to connect as '%s' with '%s'.\n", jid, pwd);
-
-	char *domain = get_domainpart(jid);
-	printf("Domainpart is '%s'.\n", domain);
-
-	struct addrinfo *addr = resolve_dns(domain);
-
-	sock = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
-	if (sock == -1) {
-		printf("Failed to get socket from OS!.");
-		return sock;
-	} else {
-		printf("Got socket number %d from OS.\n", sock);
-	}
-
-	if (connect(sock, addr->ai_addr, addr->ai_addrlen) == -1) {
-		printf("Failed to connect!\n");
-		return sock;
-	} else {
-		printf("Successfully connected.\n");
-	}
-
-	if (start_stream(sock, jid, domain) == -1) {
-		printf("Failed to init stream!\n");
-		return sock;
-	}
-	printf("Stream init sent.\n");
-
-	return sock;
-}
diff --git a/xmpp.h b/xmpp.h
deleted file mode 100644
index 622881c..0000000
--- a/xmpp.h
+++ /dev/null
@@ -1,21 +0,0 @@
-/*
- * LimoX - The Linux on mobile XMPP chat client
- * Copyright (C) 2022  xengineering
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-
-int xmpp_connect(void);
-char *get_domainpart(char *jid);