<vector>, etc.: avoid _RERAISE in favor of usual scope guards

[AlexGuteniev]

_RERAISE; expands to throw;, that is it rethrowing an exception.

This is used for cleanups in exception case.

It is inconvenient for debugging, when the same exception shows up twice.
Change this construct to usual scope guards.

[StephanTLavavej]

Agreed; the inconsistency exists because _RERAISE is the original pattern and scope guards are the modern pattern, but we hadn't overhauled all occurrences.

This can be done incrementally, e.g. file-by-file.

[StephanTLavavej]

After the above PRs (thanks!) we're currently down to the following occurrences:

• 2 in <chrono>
• 1 in <iterator>
• 1 in <ostream>
• 10 in <vector>
• 1 in <xiosbase>
• 1 in <xpolymorphic_allocator.h>
• 1 in <xtree>

[frederick-vs-ja]

• 2 in <chrono>
  • I guess scope guard is unsuitable since sometimes we need to change the exception.
• 10 in <vector>
  • There're nested try-catch-rethrow in the current implementation (now in _Insert_counted_range) which can't be directly converted to scope guards. We may need to heavily restructure _Insert_counted_range.
    

    STL/stl/inc/vector

    Lines 1173 to 1192 in 0a2d59e

    	_TRY_BEGIN
    	_Uninitialized_copy_n(_STD move(_First), _Count, _Whereptr, _Al);
    	_CATCH_ALL
    	// glue the broken pieces back together
    	_TRY_BEGIN
    	_Uninitialized_move(_Whereptr + _Count, _Whereptr + 2 * _Count, _Whereptr, _Al);
    	_CATCH_ALL
    	// vaporize the detached piece
    	_Orphan_range(_Whereptr, _Oldlast);
    	_Destroy_range(_Whereptr + _Count, _Mylast, _Al);
    	_Mylast = _Whereptr;
    	_RERAISE;
    	_CATCH_END
    	_STD _Move_unchecked(_Whereptr + 2 * _Count, _Mylast, _Whereptr + _Count);
    	_Destroy_range(_Oldlast, _Mylast, _Al);
    	_Mylast = _Oldlast;
    	_RERAISE;
    	_CATCH_END

    
    

    STL/stl/inc/vector

    Lines 1198 to 1216 in 0a2d59e

    	_TRY_BEGIN
    	_Uninitialized_copy_n(_STD move(_First), _Count, _Whereptr, _Al);
    	_CATCH_ALL
    	// glue the broken pieces back together
    	_TRY_BEGIN
    	_Uninitialized_move(_Relocated, _Mylast, _Whereptr, _Al);
    	_CATCH_ALL
    	// vaporize the detached piece
    	_Orphan_range(_Whereptr, _Oldlast);
    	_Destroy_range(_Relocated, _Mylast, _Al);
    	_Mylast = _Whereptr;
    	_RERAISE;
    	_CATCH_END
    	_Destroy_range(_Relocated, _Mylast, _Al);
    	_Mylast = _Oldlast;
    	_RERAISE;
    	_CATCH_END

• 1 in <xiosbase>
  • I don't think this is doable because iostream classes are designed to be conditionally rethrowing.