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Additions to ResultVal to make it more convenient to use.

This commit is contained in:
Yuri Kunde Schlesner 2015-01-11 03:42:18 -02:00
parent b5ee4f9df9
commit afc416c607

View file

@ -9,8 +9,9 @@
#include <type_traits>
#include <utility>
#include "common/common_types.h"
#include "common/bit_field.h"
#include "common/common_funcs.h"
#include "common/common_types.h"
// All the constants in this file come from http://3dbrew.org/wiki/Error_codes
@ -364,6 +365,17 @@ public:
return !empty() ? *GetPointer() : std::move(value);
}
/// Asserts that the result succeeded and returns a reference to it.
T& Unwrap() {
// TODO(yuriks): Should be a release assert
_assert_msg_(Common, Succeeded(), "Tried to Unwrap empty ResultVal");
return **this;
}
T&& MoveFrom() {
return std::move(Unwrap());
}
private:
typedef typename std::aligned_storage<sizeof(T), std::alignment_of<T>::value>::type StorageType;
@ -400,3 +412,15 @@ template <typename T, typename... Args>
ResultVal<T> MakeResult(Args&&... args) {
return ResultVal<T>::WithCode(RESULT_SUCCESS, std::forward<Args>(args)...);
}
/**
* Check for the success of `source` (which must evaluate to a ResultVal). If it succeeds, unwraps
* the contained value and assigns it to `target`, which can be either an l-value expression or a
* variable declaration. If it fails the return code is returned from the current function. Thus it
* can be used to cascade errors out, achieving something akin to exception handling.
*/
#define CASCADE_RESULT(target, source) \
auto CONCAT2(check_result_L, __LINE__) = source; \
if (CONCAT2(check_result_L, __LINE__).Failed()) \
return CONCAT2(check_result_L, __LINE__).Code(); \
target = std::move(*CONCAT2(check_result_L, __LINE__))