Try to do better error handling with custom allocators

8 files changed, 46 insertions, 21 deletions

diff --git a/include/alloc.h b/include/alloc.h
index 966361e..b9e03e2 100644
--- a/include/alloc.h
+++ b/include/alloc.h
@@ -1,6 +1,7 @@
 #ifndef MLIB_ALLOC_H
 #define MLIB_ALLOC_H
 
+#include <setjmp.h>
 #include <stddef.h>
 
 #include "_attrs.h"
@@ -44,6 +45,15 @@ void arena_free(arena *);
 #define arena_resz(a, T, p, n)                                                 \
 	((T *)arena_realloc((a), (p), (n), sizeof(T), alignof(T)))
 
+/* Memory allocator callbacks for memory-allocating functions */
+struct arena_ctx {
+	arena *a;
+	jmp_buf *jmp;
+};
+struct heap_ctx {
+	jmp_buf *jmp;
+};
+
 [[nodiscard]] void *alloc_arena(void *, void *, size_t, size_t, size_t);
 [[nodiscard]] void *alloc_heap(void *, void *, size_t, size_t, size_t);
 
diff --git a/lib/alloc/alloc_arena.c b/lib/alloc/alloc_arena.c
index 9ddc6e2..52d0df9 100644
--- a/lib/alloc/alloc_arena.c
+++ b/lib/alloc/alloc_arena.c
@@ -1,9 +1,21 @@
 #include <stdlib.h>
 
 #include "alloc.h"
+#include "errors.h"
+#include "macros.h"
 
 void *
-alloc_arena(void *ctx, void *ptr, size_t old, size_t new, size_t align)
+alloc_arena(void *raw_ctx, void *ptr, size_t old, size_t new, size_t align)
 {
-	return arena_realloc(ctx, ptr, old, new, 1, align);
+	struct arena_ctx *ctx = raw_ctx;
+	ASSUME(ctx != nullptr);
+	ASSUME(ctx->a != nullptr);
+
+	void *p = arena_realloc(ctx->a, ptr, old, new, 1, align);
+	if (new == 0 || p != nullptr)
+		return p;
+
+	if (ctx->jmp != nullptr)
+		longjmp(*ctx->jmp, 1);
+	err("arena_realloc:");
 }
diff --git a/lib/alloc/alloc_heap.c b/lib/alloc/alloc_heap.c
index 72cd7ad..46fbdc9 100644
--- a/lib/alloc/alloc_heap.c
+++ b/lib/alloc/alloc_heap.c
@@ -1,12 +1,26 @@
+#include <stddef.h>
+#include <setjmp.h>
 #include <stdlib.h>
 
 #include "alloc.h"
+#include "errors.h"
 
 void *
-alloc_heap(void *, void *ptr, size_t, size_t new, size_t)
+alloc_heap(void *raw_ctx, void *ptr, size_t, size_t new, size_t)
 {
-	if (new > 0)
-		return realloc(ptr, new);
-	free(ptr);
-	return nullptr;
+	if (new == 0) {
+		free(ptr);
+		return nullptr;
+	}
+
+	void *p = realloc(ptr, new);
+	if (p != nullptr)
+		return p;
+
+	struct heap_ctx *ctx = raw_ctx;
+	if (ctx == nullptr || ctx->jmp == nullptr)
+		err("realloc:");
+
+	longjmp(*ctx->jmp, 1);
+	unreachable();
 }
diff --git a/lib/unicode/string/u8casefold.c b/lib/unicode/string/u8casefold.c
index eff1e48..b4afe50 100644
--- a/lib/unicode/string/u8casefold.c
+++ b/lib/unicode/string/u8casefold.c
@@ -20,8 +20,6 @@ u8casefold(size_t *dstn, struct u8view sv, enum caseflags flags, alloc_fn alloc,
 	}
 
 	char8_t *dst = alloc(alloc_ctx, nullptr, 0, bufsz, alignof(char8_t));
-	if (dst == nullptr)
-		return nullptr;
 
 	rune ch;
 	size_t n = 0;
diff --git a/lib/unicode/string/u8lower.c b/lib/unicode/string/u8lower.c
index d5eb58c..45309b6 100644
--- a/lib/unicode/string/u8lower.c
+++ b/lib/unicode/string/u8lower.c
@@ -47,8 +47,6 @@ u8lower(size_t *dstn, struct u8view sv, enum caseflags flags, alloc_fn alloc,
 	}
 
 	char8_t *dst = alloc(alloc_ctx, nullptr, 0, bufsz, alignof(char8_t));
-	if (dst == nullptr)
-		return nullptr;
 
 	while (u8next(&ch, &sv)) {
 		rune next = 0;
diff --git a/lib/unicode/string/u8title.c b/lib/unicode/string/u8title.c
index 0c3620e..5710920 100644
--- a/lib/unicode/string/u8title.c
+++ b/lib/unicode/string/u8title.c
@@ -53,8 +53,6 @@ u8title(size_t *dstn, struct u8view sv, enum caseflags flags, alloc_fn alloc,
 	}
 
 	char8_t *dst = alloc(alloc_ctx, nullptr, 0, bufsz, alignof(char8_t));
-	if (dst == nullptr)
-		return nullptr;
 
 	while (u8next(&ch, &sv)) {
 		if (sv.p > word.p + word.len) {
diff --git a/lib/unicode/string/u8upper.c b/lib/unicode/string/u8upper.c
index df25ee7..91ae679 100644
--- a/lib/unicode/string/u8upper.c
+++ b/lib/unicode/string/u8upper.c
@@ -26,8 +26,6 @@ u8upper(size_t *dstn, struct u8view sv, enum caseflags flags, alloc_fn alloc,
 	}
 
 	char8_t *dst = alloc(alloc_ctx, nullptr, 0, bufsz, alignof(char8_t));
-	if (dst == nullptr)
-		return nullptr;
 
 	rune ch;
 	size_t n = 0;
diff --git a/test/_case-test.h b/test/_case-test.h
index 684c6ec..ea05a86 100644
--- a/test/_case-test.h
+++ b/test/_case-test.h
@@ -65,12 +65,9 @@ test(const char8_t *line, int id)
 	                                          : 0;
 
 	arena a = mkarena(0);
-	mapped.p = FUNC(&mapped.len, before, cf, alloc_arena, &a);
-
-	if (mapped.p == nullptr) {
-		warn("case %d: got null %s buffer", id, STR(CASETYPE_VERB));
-		return false;
-	}
+	mapped.p = FUNC(&mapped.len, before, cf, alloc_arena, &(struct arena_ctx){
+		.a = &a,
+	});
 
 	if (!u8eq(mapped, after)) {
 		warn("case %d: expected ‘%.*s’ but got ‘%.*s’", id, SV_PRI_ARGS(after),