initial import of the C runtime

src/runtime/c/gu/exn.c

@@ -0,0 +1,72 @@
+#include <gu/exn.h>
+#include <gu/assert.h>
+
+
+GuExn*
+gu_new_exn(GuExn* parent, GuKind* catch, GuPool* pool)
+{
+	return gu_new_s(pool, GuExn,
+			.state = GU_EXN_OK,
+			.parent = parent,
+			.catch = catch,
+			.caught = NULL,
+			.data.pool = pool,
+			.data.data = NULL);
+}
+
+void
+gu_exn_block(GuExn* err)
+{
+	if (err && err->state == GU_EXN_RAISED) {
+		err->state = GU_EXN_BLOCKED;
+	}
+}
+
+void
+gu_exn_unblock(GuExn* err)
+{
+	if (err && err->state == GU_EXN_BLOCKED) {
+		err->state = GU_EXN_RAISED;
+	}
+}
+
+GuExnData*
+gu_exn_raise_debug_(GuExn* base, GuType* type, 
+		      const char* filename, const char* func, int lineno)
+{
+	gu_require(type);
+
+	// TODO: log the error, once there's a system for dumping
+	// error objects.
+
+	GuExn* err = base;
+	
+	while (err && !(err->catch && gu_type_has_kind(type, err->catch))) {
+		err->state = GU_EXN_RAISED;
+		err = err->parent;
+	}
+	if (!err) {
+		gu_abort_(GU_ASSERT_ASSERTION, filename, func, lineno,
+			  "Unexpected error raised");
+	}
+	GuExnState old_state = err->state;
+	err->state = GU_EXN_RAISED;
+	if (old_state == GU_EXN_OK) {
+		err->caught = type;
+		if (err->data.pool) {
+			return &err->data;
+		}
+	}
+	// Exceptian had already been raised, possibly blocked, or no
+	// exception value is required.
+	return NULL;
+}
+
+GuExnData*
+gu_exn_raise_(GuExn* base, GuType* type)
+{
+	return gu_exn_raise_debug_(base, type, NULL, NULL, -1);
+}
+
+
+GU_DEFINE_TYPE(GuErrno, signed, _);