initial import of the C runtime

src/runtime/c/gu/exn.h

@@ -0,0 +1,195 @@
+#ifndef GU_EXN_H_
+#define GU_EXN_H_
+
+#include <gu/mem.h>
+#include <gu/type.h>
+
+/** @file
+ *
+ * @defgroup GuExn Exceptions
+ * Defined in <gu/exn.h>.
+ * @{
+ */
+
+/// An exception frame.
+typedef struct GuExn GuExn;
+
+/// @private
+typedef enum {
+	GU_EXN_RAISED,
+	GU_EXN_OK,
+	GU_EXN_BLOCKED
+} GuExnState;
+
+typedef struct GuExnData GuExnData;
+
+/// A structure for storing exception values.
+struct GuExnData
+/**
+ * When an exception is raised, if there is an associated value, it
+ * must be allocated from a pool that still exists when control
+ * returns to the handler of that exception. This structure is used to
+ * communicate the exception from the raiser to the handler: the
+ * handler sets #pool when setting up the exception frame, and the
+ * raiser uses that pool to allocate the value and stores that in
+ * #data. When control returns to the handler, it reads the value from
+ * there.
+ */
+{
+	
+	/// The pool that the exception value should be allocated from.
+	GuPool* const pool;
+
+	/// The exception value.
+	const void* data;
+};
+
+struct GuExn {
+	/// @privatesection
+	GuExnState state;
+	GuExn* parent;
+	GuKind* catch;
+	GuType* caught;
+	GuExnData data;
+};
+
+
+/// @name Creating exception frames
+//@{
+
+
+/// Allocate a new local exception frame.
+#define gu_exn(parent_, catch_, pool_) &(GuExn){	\
+	.state = GU_EXN_OK,	\
+	.parent = parent_,	\
+	.catch = gu_kind(catch_),	\
+	.caught = NULL,	\
+	.data.pool = pool_,		\
+	.data.data = NULL \
+}
+
+
+/// Allocate a new exception frame.
+GuExn*
+gu_new_exn(GuExn* parent, GuKind* catch_kind, GuPool* pool);
+
+
+
+static inline bool
+gu_exn_is_raised(GuExn* err) {
+	return err && (err->state == GU_EXN_RAISED);
+}
+
+static inline void
+gu_exn_clear(GuExn* err) {
+	err->caught = NULL;
+	err->state = GU_EXN_OK;
+}
+
+
+
+GuType*
+gu_exn_caught(GuExn* err);
+
+const void*
+gu_exn_caught_data(GuExn* err);
+
+/// Temporarily block a raised exception.
+void
+gu_exn_block(GuExn* err);
+
+/// Show again a blocked exception.
+void
+gu_exn_unblock(GuExn* err);
+
+//@private
+GuExnData*
+gu_exn_raise_(GuExn* err, GuType* type);
+
+//@private
+GuExnData*
+gu_exn_raise_debug_(GuExn* err, GuType* type,
+		      const char* filename, const char* func, int lineno);
+
+#ifdef NDEBUG
+#define gu_exn_raise(err_, type_)	\
+	gu_exn_raise_(err_, type_)
+#else
+#define gu_exn_raise(err_, type_)	\
+	gu_exn_raise_debug_(err_, type_, \
+			      __FILE__, __func__, __LINE__)
+#endif
+
+/// Raise an exception.
+#define gu_raise(exn, T)		\
+	gu_exn_raise(exn, gu_type(T))
+/**< 
+ * @param exn The current exception frame.
+ *
+ * @param T   The C type of the exception to raise.
+ *
+ * @return    A #GuExnData object that can be used to store the exception value, or
+ * \c NULL if no value is required.
+ * 
+ * @note The associated #GuType object for type \p T must be visible.
+ */
+
+#define gu_raise_new(error_, t_, pool_, expr_)				\
+	GU_BEGIN							\
+	GuExnData* gu_raise_err_ = gu_raise(error_, t_);		\
+	if (gu_raise_err_) {						\
+		GuPool* pool_ = gu_raise_err_->pool;			\
+		gu_raise_err_->data = expr_;				\
+	}								\
+	GU_END
+
+#define gu_raise_i(error_, t_, ...) \
+	gu_raise_new(error_, t_, gu_raise_pool_, gu_new_i(gu_raise_pool_, t_, __VA_ARGS__))
+
+
+/// Check the status of the current exception frame
+static inline bool
+gu_ok(GuExn* exn) {
+	return !GU_UNLIKELY(gu_exn_is_raised(exn));
+}
+/**<
+ * @return \c false if an exception has been raised in the frame \p exn
+ * and it has not been blocked, \c true otherwise.
+ */
+
+
+/// Return from current function if an exception has been raised.
+#define gu_return_on_exn(exn_, retval_)		\
+	GU_BEGIN					\
+	if (gu_exn_is_raised(exn_)) return retval_;	\
+	GU_END
+/**<
+ * @showinitializer
+ */
+
+
+#include <errno.h>
+
+typedef int GuErrno;
+
+extern GU_DECLARE_TYPE(GuErrno, signed);
+
+
+
+#define gu_raise_errno(error_) \
+	gu_raise_i(error_, GuErrno, errno)
+
+#if 0
+
+typedef void (*GuExnPrintFn)(GuFn* clo, void* err, FILE* out);
+
+extern GuTypeTable gu_exn_default_printer;
+
+void
+gu_exn_print(GuExn* err, FILE* out, GuTypeMap printer_map);
+
+#endif
+
+/** @} */
+
+#endif // GU_EXN_H_