Move resolve_tilde and get_config_path into libi3

libi3/get_config_path.c

@@ -0,0 +1,91 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ * © 2009-2015 Michael Stapelberg and contributors (see also: LICENSE)
+ *
+ */
+#include "libi3.h"
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+
+/*
+ * Checks if the given path exists by calling stat().
+ *
+ */
+static bool path_exists(const char *path) {
+    struct stat buf;
+    return (stat(path, &buf) == 0);
+}
+
+/*
+ * Get the path of the first configuration file found. If override_configpath
+ * is specified, that path is returned and saved for further calls. Otherwise,
+ * checks the home directory first, then the system directory first, always
+ * taking into account the XDG Base Directory Specification ($XDG_CONFIG_HOME,
+ * $XDG_CONFIG_DIRS)
+ *
+ */
+char *get_config_path(const char *override_configpath, bool use_system_paths) {
+    char *xdg_config_home, *xdg_config_dirs, *config_path;
+
+    static const char *saved_configpath = NULL;
+
+    if (override_configpath != NULL) {
+        saved_configpath = override_configpath;
+        return sstrdup(saved_configpath);
+    }
+
+    if (saved_configpath != NULL)
+        return sstrdup(saved_configpath);
+
+    /* 1: check the traditional path under the home directory */
+    config_path = resolve_tilde("~/.i3/config");
+    if (path_exists(config_path))
+        return config_path;
+    free(config_path);
+
+    /* 2: check for $XDG_CONFIG_HOME/i3/config */
+    if ((xdg_config_home = getenv("XDG_CONFIG_HOME")) == NULL)
+        xdg_config_home = "~/.config";
+
+    xdg_config_home = resolve_tilde(xdg_config_home);
+    sasprintf(&config_path, "%s/i3/config", xdg_config_home);
+    free(xdg_config_home);
+
+    if (path_exists(config_path))
+        return config_path;
+    free(config_path);
+
+    /* The below paths are considered system-level, and can be skipped if the
+     * caller only wants user-level configs. */
+    if (!use_system_paths)
+        return NULL;
+
+    /* 3: check the traditional path under /etc */
+    config_path = SYSCONFDIR "/i3/config";
+    if (path_exists(config_path))
+        return sstrdup(config_path);
+
+    /* 4: check for $XDG_CONFIG_DIRS/i3/config */
+    if ((xdg_config_dirs = getenv("XDG_CONFIG_DIRS")) == NULL)
+        xdg_config_dirs = "/etc/xdg";
+
+    char *buf = sstrdup(xdg_config_dirs);
+    char *tok = strtok(buf, ":");
+    while (tok != NULL) {
+        tok = resolve_tilde(tok);
+        sasprintf(&config_path, "%s/i3/config", tok);
+        free(tok);
+        if (path_exists(config_path)) {
+            free(buf);
+            return config_path;
+        }
+        free(config_path);
+        tok = strtok(NULL, ":");
+    }
+    free(buf);
+
+    return NULL;
+}

libi3/resolve_tilde.c

@@ -0,0 +1,45 @@
+/*
+ * vim:ts=4:sw=4:expandtab
+ *
+ * i3 - an improved dynamic tiling window manager
+ * © 2009-2015 Michael Stapelberg and contributors (see also: LICENSE)
+ *
+ */
+
+#include "libi3.h"
+#include <err.h>
+#include <glob.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * This function resolves ~ in pathnames.
+ * It may resolve wildcards in the first part of the path, but if no match
+ * or multiple matches are found, it just returns a copy of path as given.
+ *
+ */
+char *resolve_tilde(const char *path) {
+    static glob_t globbuf;
+    char *head, *tail, *result;
+
+    tail = strchr(path, '/');
+    head = strndup(path, tail ? (size_t)(tail - path) : strlen(path));
+
+    int res = glob(head, GLOB_TILDE, NULL, &globbuf);
+    free(head);
+    /* no match, or many wildcard matches are bad */
+    if (res == GLOB_NOMATCH || globbuf.gl_pathc != 1)
+        result = sstrdup(path);
+    else if (res != 0) {
+        err(EXIT_FAILURE, "glob() failed");
+    } else {
+        head = globbuf.gl_pathv[0];
+        result = scalloc(strlen(head) + (tail ? strlen(tail) : 0) + 1);
+        strncpy(result, head, strlen(head));
+        if (tail)
+            strncat(result, tail, strlen(tail));
+    }
+    globfree(&globbuf);
+
+    return result;
+}