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[iter/meta] Fix build on newer clang 

The mystery failure had to do with SFINAE failure because the template
function involved was accessing ::iter_t of a type that was also named iter_t.
In this context, apparently:

warning: ISO C++ specifies that qualified reference to 'iter_t' is a
constructor name rather than a type in this context, despite preceding 'typename' keyword
[-Winjected-class-name]

We use a new macro, also called hb_iter_t(), to get iterator type of
a type.  This uses declval/hb_decltype, and has the added benefit
that it returns correct type for const vs non-const objects, if they
have different iterators.
This commit is contained in:
Behdad Esfahbod 2019-01-26 22:44:09 +01:00
parent 5adb113baf
commit 6b6783e158
1 changed files with 12 additions and 10 deletions
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22
src/hb-iter.hh
View File

@ -49,10 +49,9 @@
*/
/* Base class for all iterators. */
template <typename Iter, typename Item = typename Iter::__item_t__>
template <typename iter_t, typename Item = typename iter_t::__item_t__>
struct hb_iter_t
{
typedef Iter iter_t;
typedef Item item_t;
static constexpr unsigned item_size = hb_static_size (Item);
static constexpr bool is_iterator = true;
@ -92,8 +91,10 @@ struct hb_iter_t
void operator = (const hb_iter_t &o HB_UNUSED) {}
};
/* Returns iterator type of a type. */
#define hb_iter_t(Iterable) decltype (hb_declval (Iterable).iter ())
#define HB_ITER_USING(Name) \
using iter_t = typename Name::iter_t; \
using item_t = typename Name::item_t; \
using Name::item_size; \
using Name::is_iterator; \
@ -227,6 +228,7 @@ struct hb_map_iter_t :
Iter it;
Proj f;
};
template <typename Proj>
struct hb_map_iter_factory_t
{
@ -234,8 +236,8 @@ struct hb_map_iter_factory_t
template <typename Iterable,
hb_enable_if (hb_is_iterable (Iterable))>
hb_map_iter_t<typename Iterable::iter_t, Proj> operator () (const Iterable &c) const
{ return hb_map_iter_t<typename Iterable::iter_t, Proj> (c.iter (), f); }
hb_map_iter_t<hb_iter_t (Iterable), Proj> operator () (const Iterable &c) const
{ return hb_map_iter_t<hb_iter_t (Iterable), Proj> (c.iter (), f); }
private:
Proj f;
@ -273,8 +275,8 @@ struct hb_filter_iter_factory_t
template <typename Iterable,
hb_enable_if (hb_is_iterable (Iterable))>
hb_filter_iter_t<typename Iterable::iter_t, Pred, Proj> operator () (const Iterable &c) const
{ return hb_filter_iter_t<typename Iterable::iter_t, Pred, Proj> (c.iter (), p, f); }
hb_filter_iter_t<hb_iter_t (Iterable), Pred, Proj> operator () (const Iterable &c) const
{ return hb_filter_iter_t<hb_iter_t (Iterable), Pred, Proj> (c.iter (), p, f); }
private:
Pred p;
@ -316,9 +318,9 @@ struct hb_zip_iter_t :
};
template <typename A, typename B,
hb_enable_if (hb_is_iterable (A) && hb_is_iterable (B))>
inline hb_zip_iter_t<typename A::iter_t, typename B::iter_t>
inline hb_zip_iter_t<hb_iter_t (A), hb_iter_t (B)>
hb_zip (const A& a, const B &b)
{ return hb_zip_iter_t<typename A::iter_t, typename B::iter_t> (a.iter (), b.iter ()); }
{ return hb_zip_iter_t<hb_iter_t (A), hb_iter_t (B)> (a.iter (), b.iter ()); }
/*
@ -330,7 +332,7 @@ template <typename C, typename V,
inline void
hb_fill (C& c, const V &v)
{
for (typename C::iter_t i (c); i; i++)
for (auto i = c.iter (); i; i++)
hb_assign (*i, v);
}