add error handling system

include/neo.h

@@ -6,6 +6,7 @@
 #error "Only gcc and clang are supported"
 #endif
 
+#include "neo/_error.h"
 #include "neo/_types.h"
 #include "neo/_stddef.h"
 

include/neo/_error.h

@@ -0,0 +1,48 @@
+/** See the end of this file for copyright and license terms. */
+
+#pragma once
+
+#include "neo/_types.h"
+
+/**
+ * Throw an error.  If `err` is `nil`, the program halts.
+ *
+ * @param err: The error pointer passed to the callee
+ * @param number: An error number appropriate for the condition,
+ *	usually one from `errno.h`
+ * @param fmt: If non nil, a printf-style format string followed by
+ *	the values to insert which will become the error message.
+ */
+__attribute__(( __format__(printf, 3, 4) ))
+void yeet(error *err, int number, const char *restrict fmt, ...);
+
+/**
+ * Functions accepting an error pointer must call this to indicate success.
+ */
+#define succeed(errptr) ({		\
+	if (errptr)			\
+		*(errptr) = nil;	\
+})
+
+/**
+ * Functions passing an error pointer must call this to acknowledge an error.
+ */
+void catch(error *err);
+
+/** Get the error number */
+#define errnum(err) ((err)->_number)
+/** Get an optional error message, this may be `nil` */
+#define errmsg(err) ((err)->_message)
+
+/*
+ * This file is part of libneo.
+ * Copyright (c) 2021 Fefie <owo@fef.moe>.
+ *
+ * libneo is non-violent software: you may only use, redistribute,
+ * and/or modify it under the terms of the CNPLv6+ as found in
+ * the LICENSE file in the source code root directory or at
+ * <https://git.pixie.town/thufie/CNPL>.
+ *
+ * libneo comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPLv6+ for details.
+ */

src/CMakeLists.txt

@@ -25,6 +25,7 @@ target_include_directories(neo PRIVATE
 )
 
 target_sources(neo PRIVATE
+    ./error.c
     ./nref.c
 )
 

src/error.c

@@ -0,0 +1,81 @@
+/** See the end of this file for copyright and license terms. */
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "neo/_error.h"
+#include "neo/_nref.h"
+#include "neo/_stddef.h"
+#include "neo/_string.h"
+#include "neo/_types.h"
+#include "neo/toolchain.h"
+
+/* flags for the error structure */
+#define NEO_ERR_CAUGHT		(1 << 0)
+
+/* TODO: we need one of these for every thread */
+static struct _neo_error _neo_error_instance = {
+	._number = 0,
+	._message = nil,
+	._flags = NEO_ERR_CAUGHT,
+};
+
+void yeet(error *err, int number, const char *restrict fmt, ...)
+{
+	va_list vargs;
+	usize msg_capacity = 64;
+	char *msg = nil;
+	int printf_ret;
+
+	if (fmt != nil) {
+		do {
+			msg = nalloc(msg_capacity, nil);
+			va_start(vargs, fmt);
+			printf_ret = vsnprintf(msg, msg_capacity, fmt, vargs);
+			va_end(vargs);
+			if (printf_ret > 0) {
+				msg_capacity += printf_ret;
+				nfree(msg);
+				msg = nil;
+			} else if (printf_ret < 0) {
+				write(1, "Runtime error\n", 14);
+				exit(1);
+			}
+		} while (msg == nil);
+	} else {
+		msg = "Runtime error";
+	}
+
+	if (err == nil) {
+		write(2, msg, strlen(msg));
+		exit(number);
+	}
+
+	*err = &_neo_error_instance;
+	(*err)->_number = number;
+	(*err)->_message = nstr(msg, nil);
+	(*err)->_flags &= ~NEO_ERR_CAUGHT;
+}
+
+void catch(error *err)
+{
+	if ((*err)->_message)
+		nput((*err)->_message);
+	(*err)->_flags |= NEO_ERR_CAUGHT;
+	*err = nil;
+}
+
+/*
+ * This file is part of libneo.
+ * Copyright (c) 2021 Fefie <owo@fef.moe>.
+ *
+ * libneo is non-violent software: you may only use, redistribute,
+ * and/or modify it under the terms of the CNPLv6+ as found in
+ * the LICENSE file in the source code root directory or at
+ * <https://git.pixie.town/thufie/CNPL>.
+ *
+ * libneo comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPLv6+ for details.
+ */

src/include/neo/toolchain.h

@@ -0,0 +1,24 @@
+/** See the end of this file for copyright and license terms. */
+
+#pragma once
+
+#define __neo_section(name) __attribute__(( __section__(#name) ))
+
+#define __neo_init(fn) \
+	__neo_section(.init_array) static void (*__neo_init_##fn)(void) = fn
+
+#define __neo_fini(fn) \
+	__neo_section(.fini_array) static void (*__neo_fini_##fn)(void) = fn
+
+/*
+ * This file is part of libneo.
+ * Copyright (c) 2021 Fefie <owo@fef.moe>.
+ *
+ * libneo is non-violent software: you may only use, redistribute,
+ * and/or modify it under the terms of the CNPLv6+ as found in
+ * the LICENSE file in the source code root directory or at
+ * <https://git.pixie.town/thufie/CNPL>.
+ *
+ * libneo comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPLv6+ for details.
+ */