1 files changed, 129 insertions, 0 deletions
diff --git a/extra/edit/xdg.c b/extra/edit/xdg.c
new file mode 100644
index 0000000..b9015b2
--- /dev/null
+++ b/extra/edit/xdg.c
@@ -0,0 +1,129 @@
+/* Copyright (C) 2019, 2020  June McEnroe <june@causal.agency>
+ *
+ * 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/>.
+ *
+ * Additional permission under GNU GPL version 3 section 7:
+ *
+ * If you modify this Program, or any covered work, by linking or
+ * combining it with OpenSSL (or a modified version of that library),
+ * containing parts covered by the terms of the OpenSSL License and the
+ * original SSLeay license, the licensors of this Program grant you
+ * additional permission to convey the resulting work. Corresponding
+ * Source for a non-source form of such a combination shall include the
+ * source code for the parts of OpenSSL used as well as that of the
+ * covered work.
+ */
+
+#include <err.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sysexits.h>
+
+#define SUBDIR "pounce"
+
+struct Base {
+	const char *envHome;
+	const char *envDirs;
+	const char *defHome;
+	const char *defDirs;
+};
+
+static const struct Base Config = {
+	.envHome = "XDG_CONFIG_HOME",
+	.envDirs = "XDG_CONFIG_DIRS",
+	.defHome = ".config",
+	.defDirs = "/etc/xdg",
+};
+
+static const struct Base Data = {
+	.envHome = "XDG_DATA_HOME",
+	.envDirs = "XDG_DATA_DIRS",
+	.defHome = ".local/share",
+	.defDirs = "/usr/local/share:/usr/share",
+};
+
+static char *basePath(
+	struct Base base, char *buf, size_t cap, const char *path, int i
+) {
+	if (path[strspn(path, ".")] == '/') {
+		if (i > 0) return NULL;
+		snprintf(buf, cap, "%s", path);
+		return buf;
+	}
+
+	if (i > 0) {
+		const char *dirs = getenv(base.envDirs);
+		if (!dirs) dirs = base.defDirs;
+		for (; i > 1; --i) {
+			dirs += strcspn(dirs, ":");
+			dirs += (*dirs == ':');
+		}
+		if (!*dirs) return NULL;
+		snprintf(
+			buf, cap, "%.*s/" SUBDIR "/%s",
+			(int)strcspn(dirs, ":"), dirs, path
+		);
+		return buf;
+	}
+
+	const char *home = getenv("HOME");
+	const char *baseHome = getenv(base.envHome);
+	if (baseHome) {
+		snprintf(buf, cap, "%s/" SUBDIR "/%s", baseHome, path);
+	} else if (home) {
+		snprintf(buf, cap, "%s/%s/" SUBDIR "/%s", home, base.defHome, path);
+	} else {
+		errx(EX_USAGE, "HOME unset");
+	}
+	return buf;
+}
+
+char *configPath(char *buf, size_t cap, const char *path, int i) {
+	return basePath(Config, buf, cap, path, i);
+}
+
+char *dataPath(char *buf, size_t cap, const char *path, int i) {
+	return basePath(Data, buf, cap, path, i);
+}
+
+FILE *configOpen(const char *path, const char *mode) {
+	char buf[PATH_MAX];
+	for (int i = 0; configPath(buf, sizeof(buf), path, i); ++i) {
+		FILE *file = fopen(buf, mode);
+		if (file) return file;
+		if (errno != ENOENT) warn("%s", buf);
+	}
+	warn("%s", configPath(buf, sizeof(buf), path, 0));
+	return NULL;
+}
+
+FILE *dataOpen(const char *path, const char *mode) {
+	char buf[PATH_MAX];
+	for (int i = 0; dataPath(buf, sizeof(buf), path, i); ++i) {
+		FILE *file = fopen(buf, mode);
+		if (file) return file;
+		if (errno != ENOENT) warn("%s", buf);
+	}
+	if (mode[0] != 'r') {
+		int error = mkdir(dataPath(buf, sizeof(buf), "", 0), S_IRWXU);
+		if (error && errno != EEXIST) warn("%s", buf);
+	}
+	FILE *file = fopen(dataPath(buf, sizeof(buf), path, 0), mode);
+	if (!file) warn("%s", buf);
+	return file;
+}