rcx

commit d3d88235076197305a01e6460f43ea302b8809d1
parent efabee7b081c5b9805bc3046e1c27eb54f45bd50
Author: Robert Russell <robertrussell.72001@gmail.com>
Date:   Wed,  1 Feb 2023 21:19:23 -0800

Tentatively add error handling module

This is so my libraries can have a consistent API for error handling, rather
than me doing it ad hoc every time, which is what I'm currently doing.

Functions that, e.g., return a nonnegative int on success should probably still
use negative integers to signal errors, because
	if (f(x) < 0) {...}
is much nicer than
	if (R_ERR(f(x))) {...}
Although I'd probably write
	rerr = f(x);
	if (R_ERR(rerr)) {...}
instead of the latter.

In the future it might be worth adding an error source in rcx for libc/posix
errors.

Diffstat:
M
Makefile
 | 
2
++
M
inc/rcx/all.h
 | 
1
+
A
inc/rcx/error.h
 | 
34
++++++++++++++++++++++++++++++++++
A
src/error.c
 | 
27
+++++++++++++++++++++++++++

4 files changed, 64 insertions(+), 0 deletions(-)
diff --git a/Makefile b/Makefile
@@ -6,6 +6,7 @@ SRC =\
 	src/alloc.c\
 	src/bench.c\
 	src/bits.c\
+	src/error.c\
 	src/log.c\
 	src/str.c\
 	src/unicode.c\
@@ -22,6 +23,7 @@ librcx.a: $(SRC:.c=.o)
 src/alloc.o: src/alloc.c inc/rcx/alloc.h inc/rcx/def.h inc/rcx/log.h inc/rcx/rcx.h inc/rcx/internal/util.h config.mk
 src/bench.o: src/bench.c inc/rcx/bench.h inc/rcx/def.h inc/rcx/log.h inc/rcx/rcx.h config.mk
 src/bits.o: src/bits.c inc/rcx/bits.h inc/rcx/def.h inc/rcx/rcx.h config.mk
+src/error.o: src/error.c inc/rcx/def.h inc/rcx/error.h inc/rcx/log.h inc/rcx/rcx.h config.mk
 src/log.o: src/log.c inc/rcx/def.h inc/rcx/log.h inc/rcx/rcx.h config.mk
 src/opt.o: src/opt.c inc/rcx/def.h inc/rcx/opt.h inc/rcx/rcx.h config.mk
 src/str.o: src/str.c inc/rcx/alloc.h inc/rcx/def.h inc/rcx/log.h inc/rcx/rcx.h inc/rcx/str.h config.mk
diff --git a/inc/rcx/all.h b/inc/rcx/all.h
@@ -2,6 +2,7 @@
 #include "rcx/alloc.h"
 #include "rcx/bits.h"
 #include "rcx/deque.h"
+#include "rcx/error.h"
 #include "rcx/log.h"
 #include "rcx/opt.h"
 #include "rcx/rcx.h"
diff --git a/inc/rcx/error.h b/inc/rcx/error.h
@@ -0,0 +1,34 @@
+#pragma once
+
+#include "rcx/def.h"
+
+#define R_ERR(e) ((e).code != 0)
+
+typedef struct RError RError;
+typedef struct RErrorSource RErrorSource;
+
+struct RErrorSource {
+	char *name;
+	/* Convert err to a string and write the result to buf, which must have
+	 * length len >= 128. If the string does not fit in the given buffer,
+	 * truncate in a source-specific manner (e.g., append an ellipsis). */
+	void (*to_string)(char *buf, usize len, RError err);
+	/* Free any data associated with err. This field can be NULL. */
+	void (*free)(RError err);
+};
+
+struct RError {
+	int code; /* 0 iff success */
+	RErrorSource *src;
+	union {
+		i64 i;
+		u64 u;
+		double f;
+		char *s;
+		void *p;
+	} u; /* Subject to source-specific semantics. */
+};
+
+void r_error_string(char *buf, usize len, RError err);
+void r_error_fatal(RError err);
+void r_error_drop(RError err);
diff --git a/src/error.c b/src/error.c
@@ -0,0 +1,27 @@
+#include <assert.h>
+
+#include "rcx/error.h"
+#include "rcx/log.h"
+#include "rcx/rcx.h"
+
+void
+r_error_string(char *buf, usize len, RError err) {
+	assert(len >= 128);
+	err.src->to_string(buf, len, err);
+}
+
+void
+r_error_fatal(RError err) {
+	if (R_ERR(err)) {
+		char buf[128];
+		r_error_string(buf, sizeof buf, err);
+		r_fatalf("%s", buf);
+	}
+}
+
+void
+r_error_drop(RError err) {
+	if (R_ERR(err)) {
+		err.src->free(err);
+	}
+}