libfonts_get_default_font.c

/* See LICENSE file for copyright and license details. */
#include "common.h"
#ifndef TEST


static int
find(char **outp, const char *dir_part1, const char *dir_part2, const char *dir_part3, struct libfonts_context *ctx)
{
	(void) outp;
	(void) dir_part1;
	(void) dir_part2;
	(void) dir_part3;
	(void) ctx;
	return 0; /* TODO implement find() */
}

static int
getn(char **outp, const char *file_part1, size_t file_part1_len, const char *file_part2,
     const char *name, struct libfonts_context *ctx)
{
	size_t file_part2_len = strlen(file_part2);
	char *path;
	int fd;
	ssize_t len;
	char *line, *buf = NULL;
	size_t size = 0, off = 0, avail = 0;
	char *value;
	size_t lineno = 0;

	*outp = NULL;

	if (file_part1_len > SIZE_MAX - file_part2_len - 1)
		goto enomem;

	path = malloc(file_part1_len + file_part2_len + 1);
	if (!path) {
	enomem:
		errno = ENOMEM;
		return -1;
	}

	memcpy(path, file_part1, file_part1_len);
	memcpy(&path[file_part1_len], file_part2, file_part2_len + 1);

open_again:
	fd = open(path, O_RDONLY);
	if (fd < 0) {
		switch (errno) {
		case EINTR:
			goto open_again;
		case EMFILE:
		case ENFILE:
		case ENOMEM:
		case ENOSPC:
			free(path);
			return -1;
		case EFBIG:
		case EOVERFLOW:
		case EISDIR:
		case ELOOP:
		case ENODEV:
		case ENOTDIR:
		case ENXIO:
			warning(ctx, errno, "libfonts_get_default_font", "failed to open %s:", path);
			goto out;
		default:
			goto out;
		}
	}

	for (;;) {
		len = libfonts_getline__(fd, &line, &buf, &size, &off, &avail);
		if (len < 0) {
			if (errno == EINTR)
				continue;
			free(*outp);
			*outp = NULL;
		fail:
			free(buf);
			free(path);
			close(fd);
			return -1;
		}
		if (!len)
			break;
		line[len -= 1] = '\0';
		lineno++;

		while (isblank(*line)) {
			line++;
			len--;
		}
		if (!*line || *line == '#')
			continue;
		while (len && isblank(line[len - 1]))
			len -= 1;
		line[len] = '\0';

		value = libfonts_confsplit__(line);
		if (!value) {
			warning(ctx, 0, "libfonts_get_default_font", "bad line in %s at line %zu", path, lineno);
			continue;
		}

		if (!strcmp(line, name)) {
			if (*outp) {
				warning(ctx, 0, "libfonts_get_default_font", "duplicate definition in %s at line %zu", path, lineno);
				free(*outp);
				*outp = NULL;
			}
			*outp = strdup(value);
			if (!*outp)
				goto fail;
		} else if (strcmp(line, "sans-serif") && strcmp(line, "serif") && strcmp(line, "monospace")) {
			warning(ctx, 0, "libfonts_get_default_font", "bad font class in %s at line %zu: %s", path, lineno, line);
		}
	}

	free(buf);
	close(fd);

out:
	free(path);
	return *outp != NULL;
}

static int
get(char **outp, const char *file_part1, const char *file_part2, const char *name, struct libfonts_context *ctx)
{
	return getn(outp, file_part1, strlen(file_part1), file_part2, name, ctx);
}

char *
libfonts_get_default_font(enum libfonts_default_font font, struct libfonts_context *ctx)
{
	const char *env, *var, *next, *confenv, *homeenv;
	char *ret, *home = NULL;
	int r, saved_errno = errno;
	size_t len;

	if (font == LIBFONTS_DEFAULT_SANS_SERIF) {
		env = "LIBFONTS_DEFAULT_SANS_SERIF";
		var = "sans-serif";
	} else if (font == LIBFONTS_DEFAULT_SERIF) {
		env = "LIBFONTS_DEFAULT_SERIF";
		var = "serif";
	} else if (font == LIBFONTS_DEFAULT_MONOSPACE) {
		env = "LIBFONTS_DEFAULT_MONOSPACE";
		var = "monospace";
	} else {
		errno = EINVAL;
		return NULL;
	}

	env = libfonts_getenv__(env, ctx);
	if (env && *env)
		return strdup(env);

	confenv = libfonts_getenv__("XDG_CONFIG_HOME", ctx);
	if (confenv && *confenv) {
		r = get(&ret, confenv, "/libfonts/default-fonts.conf", var, ctx);
		if (r)
			goto out;
	}

	homeenv = libfonts_getenv__("HOME", ctx);
	if (homeenv && *homeenv) {
		r = get(&ret, homeenv, "/.config/libfonts/default-fonts.conf", var, ctx);
		if (r)
			goto out;
		r = get(&ret, homeenv, "/.libfonts/default-fonts.conf", var, ctx);
		if (r)
			goto out;
	}

	home = libfonts_gethome__(ctx);
	if (home && *home) {
		r = get(&ret, home, "/.config/libfonts/default-fonts.conf", var, ctx);
		if (r)
			goto out;
		r = get(&ret, home, "/.libfonts/default-fonts.conf", var, ctx);
		if (r)
			goto out;
	}

	if (confenv && *confenv) {
		r = find(&ret, env, "/libfonts/", var, ctx);
		if (r)
			goto out;
	}

	if (homeenv && *homeenv) {
		r = find(&ret, homeenv, "/.config/libfonts/", var, ctx);
		if (r)
			goto out;
		r = find(&ret, homeenv, "/.libfonts/", var, ctx);
		if (r)
			goto out;
	}

	if (home && *home) {
		r = find(&ret, home, "/.config/libfonts/", var, ctx);
		if (r)
			goto out;
		r = find(&ret, home, "/.libfonts/", var, ctx);
		if (r)
			goto out;
	}

	env = libfonts_getenv__("XDG_CONFIG_DIRS", ctx);
	if (env && *env) {
		do {
			next = strchr(&env[1], ':');
			len = next ? (size_t)(next - env) : strlen(env);
			if (len) {
				r = getn(&ret, env, len, "/libfonts/default-fonts.conf", var, ctx);
				if (r)
					goto out;
			}
			env += len + 1;
		} while (next);
	}

	r = get(&ret, "/etc", "/libfonts/default-fonts.conf", var, ctx);
	if (r)
		goto out;

	r = find(&ret, "/etc", "/libfonts/", var, ctx);
	if (r)
		goto out;

	/* TODO as a last resort look around for some font that matches the specification as well as possible */

	ret = NULL;
	r = 0;

out:
	free(home);
	if (r < 0)
		return NULL;
	errno = saved_errno;
	return ret;
}


#else


int
main(void)
{
	return 0; /* XXX add test */
}


#endif