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author | Stephan Bergmann <sbergman@redhat.com> | 2019-12-06 16:36:01 +0100 |
---|---|---|
committer | Thorsten Behrens <thorsten.behrens@allotropia.de> | 2021-04-09 23:22:01 +0200 |
commit | 6572dbc2fa36fb9189bd1ed21748e73a88418e15 (patch) | |
tree | 6d222150affeba0b7ec98f4b3479f06801c0a96d | |
parent | Add --with-latest-c++ to explicitly opt in for -std=c++20/-std:c++latest (diff) | |
download | core-6572dbc2fa36fb9189bd1ed21748e73a88418e15.tar.gz core-6572dbc2fa36fb9189bd1ed21748e73a88418e15.zip |
Adapt o3tl::span to P1872R0
..."span should have size_type, not index_type"
(<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1872r0.pdf>), as
implemented by libc++ since <https://github.com/llvm/llvm-project/commit/
1466335cf4b2854a0be1defcf279fe50772bad6f> "[libc++][P1872] span should have
size_type, not index_type."
All uses of index_type had been added to mitigate the previous std::span change
from signed (ptrdiff_t) to unsigned (size_t) index_type, see
6ef8420fdbf8dff16de13147c5ab833bc5e01121 "Adapt o3tl::span to updated C++2a
std::span". There is no easy solution to transparently support all three
std::span variants currently out there (signed index_type, unsigned index_type,
unsigned size_type), without causing compilation failures due to
CPPUNIT_ASSERT_EQUAL with arguments of different types, or compiler warnings
about mixed signed/unsigned comparisons. So rule out the oldest std::span
variant (signed index_type) in configure.ac (so that o3tl::span will use its
own hand-rolled code in that case) and simplify the uses of index_type to
std::size_t (as had already been mentioned in
6ef8420fdbf8dff16de13147c5ab833bc5e01121).
Reviewed-on: https://gerrit.libreoffice.org/84652
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
(cherry picked from commit 8e6865188242bccb3d8aa857ddc990d72a058d3d)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/87757
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit bb9833594b031c6d0ec91422f85968c4b1f2f8bc)
Change-Id: I6ddf424ffb7941da3f69ad66fd29ecd35f09afae
-rw-r--r-- | config_host/config_global.h.in | 3 | ||||
-rw-r--r-- | configure.ac | 16 | ||||
-rw-r--r-- | include/o3tl/span.hxx | 14 | ||||
-rw-r--r-- | o3tl/qa/test-span.cxx | 7 | ||||
-rw-r--r-- | sfx2/source/control/dispatch.cxx | 3 |
5 files changed, 33 insertions, 10 deletions
diff --git a/config_host/config_global.h.in b/config_host/config_global.h.in index 2e986fbe24b6..0b44ad05373e 100644 --- a/config_host/config_global.h.in +++ b/config_host/config_global.h.in @@ -24,6 +24,9 @@ Any change in this header will cause a rebuild of almost everything. /* Guaranteed copy elision (C++17), __cpp_guaranteed_copy_elision (C++2a): */ #define HAVE_CPP_GUARANTEED_COPY_ELISION 0 +// Useable C++2a <span>: +#define HAVE_CPP_SPAN 0 + /* GCC bug <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87150> "move ctor wrongly chosen in return stmt (derived vs. base)": */ #define HAVE_GCC_BUG_87150 0 diff --git a/configure.ac b/configure.ac index 2b33e5f0bc0a..0e61b295b66f 100644 --- a/configure.ac +++ b/configure.ac @@ -6766,6 +6766,22 @@ AC_COMPILE_IFELSE([AC_LANG_SOURCE([ CXXFLAGS=$save_CXXFLAGS AC_LANG_POP([C++]) +AC_MSG_CHECKING([whether $CXX supports C++2a <span> with unsigned size_type]) +AC_LANG_PUSH([C++]) +save_CXXFLAGS=$CXXFLAGS +CXXFLAGS="$CXXFLAGS $CXXFLAGS_CXX11" +AC_COMPILE_IFELSE([AC_LANG_SOURCE([ + #include <span> + #include <type_traits> + // Don't check size_type directly, as it was called index_type before P1872R0: + void f(std::span<int> s) { static_assert(std::is_unsigned_v<decltype(s.size())>); }; + ])], [ + AC_DEFINE([HAVE_CPP_SPAN],[1]) + AC_MSG_RESULT([yes]) + ], [AC_MSG_RESULT([no])]) +CXXFLAGS=$save_CXXFLAGS +AC_LANG_POP([C++]) + AC_MSG_CHECKING([whether $CXX has GCC bug 87150]) AC_LANG_PUSH([C++]) save_CXXFLAGS=$CXXFLAGS diff --git a/include/o3tl/span.hxx b/include/o3tl/span.hxx index 1618b86df897..b19d2d847ac7 100644 --- a/include/o3tl/span.hxx +++ b/include/o3tl/span.hxx @@ -12,7 +12,9 @@ #include <sal/config.h> -#if __has_include(<span>) +#include <config_global.h> + +#if HAVE_CPP_SPAN #include <span> @@ -40,7 +42,7 @@ public: using iterator = pointer; using const_reverse_iterator = std::reverse_iterator<const_iterator>; using reverse_iterator = std::reverse_iterator<iterator>; - using index_type = std::size_t; + using size_type = std::size_t; using difference_type = std::ptrdiff_t; constexpr span() noexcept : data_(nullptr), size_(0) {} @@ -48,7 +50,7 @@ public: template<std::size_t N> constexpr span (T (&a)[N]) noexcept : data_(a), size_(N) {} - constexpr span (T *a, index_type len) noexcept + constexpr span (T *a, size_type len) noexcept : data_(a), size_(len) { // not terribly sure about this, might need to strengthen it @@ -72,9 +74,9 @@ public: { return rbegin(); } constexpr const_reverse_iterator crend() const noexcept { return rend(); } - constexpr index_type size() const noexcept { return size_; } + constexpr size_type size() const noexcept { return size_; } - constexpr reference operator [](index_type pos) const { + constexpr reference operator [](size_type pos) const { assert(pos < size()); return data_[pos]; } @@ -83,7 +85,7 @@ public: private: pointer data_; - index_type size_; + size_type size_; }; } // namespace o3tl diff --git a/o3tl/qa/test-span.cxx b/o3tl/qa/test-span.cxx index 7ec67fa7fd91..3cb78ace1db2 100644 --- a/o3tl/qa/test-span.cxx +++ b/o3tl/qa/test-span.cxx @@ -9,6 +9,7 @@ #include <sal/config.h> +#include <cstddef> #include <utility> #include <cppunit/TestAssert.h> @@ -42,7 +43,7 @@ private: CPPUNIT_ASSERT_EQUAL(3, *v.crbegin()); CPPUNIT_ASSERT_EQUAL( o3tl::span<int>::difference_type(3), v.crend() - v.crbegin()); - CPPUNIT_ASSERT_EQUAL(o3tl::span<int>::index_type(3), v.size()); + CPPUNIT_ASSERT_EQUAL(std::size_t(3), v.size()); CPPUNIT_ASSERT(!v.empty()); CPPUNIT_ASSERT_EQUAL(2, v[1]); CPPUNIT_ASSERT_EQUAL(1, *v.data()); @@ -52,8 +53,8 @@ private: o3tl::span<int const> v1( d1 ); o3tl::span<int const> v2( d2 ); std::swap(v1, v2); - CPPUNIT_ASSERT_EQUAL(o3tl::span<int>::index_type(4), v1.size()); - CPPUNIT_ASSERT_EQUAL(o3tl::span<int>::index_type(2), v2.size()); + CPPUNIT_ASSERT_EQUAL(std::size_t(4), v1.size()); + CPPUNIT_ASSERT_EQUAL(std::size_t(2), v2.size()); } } }; diff --git a/sfx2/source/control/dispatch.cxx b/sfx2/source/control/dispatch.cxx index 702e6064f157..c3f3ad60c10c 100644 --- a/sfx2/source/control/dispatch.cxx +++ b/sfx2/source/control/dispatch.cxx @@ -20,6 +20,7 @@ #include <config_features.h> #include <algorithm> +#include <cstddef> #include <deque> #include <vector> @@ -1547,7 +1548,7 @@ void SfxDispatcher::SetSlotFilter(SfxSlotFilterState nEnable, { #ifdef DBG_UTIL // Check Array - for ( o3tl::span<sal_uInt16 const>::index_type n = 1; n < pSIDs.size(); ++n ) + for ( std::size_t n = 1; n < pSIDs.size(); ++n ) DBG_ASSERT( pSIDs[n] > pSIDs[n-1], "SetSlotFilter: SIDs not sorted" ); #endif |