jade
e34833c025
This:
- Converts a bunch of C style casts into C++ casts.
- Removes some very silly pointer subtraction code (which is no more or
less busted on i686 than it began)
- Fixes some "technically UB" that never had to be UB in the first
place.
- Makes finally follow the noexcept status of the inner function. Maybe
in the future we should ban the function from not being noexcept, but
that is not today.
- Makes various locally-used exceptions inherit from std::exception.
Change-Id: I22e66972602604989b5e494fd940b93e0e6e9297
47 lines
1.5 KiB
C++
47 lines
1.5 KiB
C++
#pragma once
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///@file
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#include <cassert>
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#include <exception>
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/**
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* A trivial class to run a function at the end of a scope.
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*/
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template<typename Fn>
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class Finally
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{
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private:
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Fn fun;
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bool movedFrom = false;
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public:
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Finally(Fn fun) : fun(std::move(fun)) { }
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// Copying Finallys is definitely not a good idea and will cause them to be
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// called twice.
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Finally(Finally &other) = delete;
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Finally(Finally &&other) : fun(std::move(other.fun)) {
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other.movedFrom = true;
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}
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~Finally() noexcept(noexcept(fun()))
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{
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try {
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if (!movedFrom)
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fun();
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} catch (...) {
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// finally may only throw an exception if exception handling is not already
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// in progress. if handling *is* in progress we have to return cleanly here
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// but are still prohibited from doing so since eating the exception would,
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// in almost all cases, mess up error handling even more. the only good way
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// to handle this is to abort entirely and leave a message, so we'll assert
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// (and rethrow anyway, just as a defense against possible NASSERT builds.)
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if (std::uncaught_exceptions()) {
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assert(false &&
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"Finally function threw an exception during exception handling. "
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"this is not what you want, please use some other methods (like "
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"std::promise or async) instead.");
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}
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throw;
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}
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}
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};
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