Move fs.basename and fs.dirname into the path library, create errors.h

lpath.c

@@ -0,0 +1,98 @@
+/***
+ * File system path manipulation.
+ * @module path
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <lua.h>
+#include <lauxlib.h>
+
+#include "callisto.h"
+#include "errors.h"
+#include "util.h"
+
+
+/***
+ * Returns the last component of the given pathname,
+ * removing any trailing '/' characters. If the given
+ * path consists entirely of '/' characters, the string
+ * `"/"` is returned. If *path* is an empty string,
+ * the string `"."` is returned.
+ *
+ * This function may return nil if the given
+ * pathname exceeds the system's path length
+ * limit (On most Linux systems this will be 4096).
+ *
+ * @function basename
+ * @usage path.basename(arg[0])
+ * @tparam string path The path to process.
+ */
+static int
+path_basename(lua_State *L)
+{
+	const char *ret;
+	char *path; /* parameter 1 (string) */
+
+	path = strndup(luaL_checkstring(L, 1), lua_rawlen(L, 1));
+	ret  = basename(path);
+
+	if (ret == NULL && errno == ENAMETOOLONG) /* check if path is too long */
+		return lfail(L, E_PATHNAMETOOLONG);
+
+	lua_pushstring(L, ret);
+	return 1;
+}
+
+/***
+ * Returns the parent directory of the pathname
+ * given. Any trailing '/' characters are not
+ * counted as part of the directory name.
+ * If the given path is an empty string or contains
+ * no '/' characters, the string `"."` is returned,
+ * signifying the current directory.
+ *
+ * This function may return nil if the given
+ * pathname exceeds the system's path length
+ * limit (On most Linux systems this will be 4096).
+ *
+ * @function dirname
+ * @usage path.dirname(arg[0])
+ * @tparam string path The path to process.
+ */
+static int
+path_dirname(lua_State *L)
+{
+	const char *ret;
+	char *path; /* parameter 1 (string) */
+
+	path = strndup(luaL_checkstring(L, 1), lua_rawlen(L, 1));
+	ret  = dirname(path);
+
+	if (ret == NULL && errno == ENAMETOOLONG) /* check if path is too long */
+		return lfail(L, E_PATHNAMETOOLONG);
+
+	lua_pushstring(L, ret);
+	return 1;
+}
+
+static const luaL_Reg pathlib[] = {
+	{"basename", path_basename},
+	{"dirname",  path_dirname},
+	{NULL, NULL}
+};
+
+int
+luaopen_path(lua_State *L)
+{
+	luaL_newlib(L, pathlib);
+	return 1;
+}