Implement LWG 3013 - some filesystem members should not be noexcept.

LWG 3013 points out that the constructors and increment members
of the directory iterators need to allocate, and therefore cannot
be marked noexcept.

It also points out that `is_empty` and `copy` likely need to allocate
as well, and as such can also not be noexcept.

This patch speculatively implements the resolution removing noexcept,
because libc++ does indeed have the possibility of throwing on allocation
failure.

llvm-svn: 316941

7 files changed, 43 insertions, 32 deletions

diff --git a/libcxx/include/experimental/filesystem b/libcxx/include/experimental/filesystem
index 42157ba309b..747f62f2268 100644
--- a/libcxx/include/experimental/filesystem
+++ b/libcxx/include/experimental/filesystem
@@ -81,10 +81,10 @@
     path canonical(const path& p, const path& base, error_code& ec);
 
     void copy(const path& from, const path& to);
-    void copy(const path& from, const path& to, error_code& ec) _NOEXCEPT;
+    void copy(const path& from, const path& to, error_code& ec);
     void copy(const path& from, const path& to, copy_options options);
     void copy(const path& from, const path& to, copy_options options,
-                   error_code& ec) _NOEXCEPT;
+                   error_code& ec);
 
     bool copy_file(const path& from, const path& to);
     bool copy_file(const path& from, const path& to, error_code& ec) _NOEXCEPT;
@@ -1351,7 +1351,7 @@ void copy(const path& __from, const path& __to) {
 }
 
 inline _LIBCPP_INLINE_VISIBILITY
-void copy(const path& __from, const path& __to, error_code& __ec) _NOEXCEPT {
+void copy(const path& __from, const path& __to, error_code& __ec) {
     __copy(__from, __to, copy_options::none, &__ec);
 }
 
@@ -1362,7 +1362,7 @@ void copy(const path& __from, const path& __to, copy_options __opt) {
 
 inline _LIBCPP_INLINE_VISIBILITY
 void copy(const path& __from, const path& __to,
-          copy_options __opt, error_code& __ec) _NOEXCEPT {
+          copy_options __opt, error_code& __ec) {
     __copy(__from, __to, __opt, &__ec);
 }
 
@@ -1561,7 +1561,7 @@ bool is_empty(const path& __p) {
 }
 
 inline _LIBCPP_INLINE_VISIBILITY
-bool is_empty(const path& __p, error_code& __ec) _NOEXCEPT {
+bool is_empty(const path& __p, error_code& __ec) {
     return __fs_is_empty(__p, &__ec);
 }
 
@@ -1903,12 +1903,12 @@ public:
         : directory_iterator(__p, nullptr, __opts)
     { }
 
-    directory_iterator(const path& __p, error_code& __ec) _NOEXCEPT
+    directory_iterator(const path& __p, error_code& __ec)
         : directory_iterator(__p, &__ec)
     { }
 
     directory_iterator(const path& __p, directory_options __opts,
-                       error_code& __ec) _NOEXCEPT
+                       error_code& __ec)
         : directory_iterator(__p, &__ec, __opts)
     { }
 
@@ -1943,7 +1943,7 @@ public:
         return __p;
     }
 
-    directory_iterator& increment(error_code& __ec) _NOEXCEPT
+    directory_iterator& increment(error_code& __ec)
     { return __increment(&__ec); }
 
 private:
@@ -2013,12 +2013,12 @@ public:
 
     _LIBCPP_INLINE_VISIBILITY
     recursive_directory_iterator(const path& __p,
-        directory_options __xoptions, error_code& __ec) _NOEXCEPT
+        directory_options __xoptions, error_code& __ec)
         : recursive_directory_iterator(__p, __xoptions, &__ec)
     { }
 
     _LIBCPP_INLINE_VISIBILITY
-    recursive_directory_iterator(const path& __p, error_code& __ec) _NOEXCEPT
+    recursive_directory_iterator(const path& __p, error_code& __ec)
         : recursive_directory_iterator(__p, directory_options::none,  &__ec)
     { }
 
@@ -2060,7 +2060,7 @@ public:
     }
 
     _LIBCPP_INLINE_VISIBILITY
-    recursive_directory_iterator& increment(error_code& __ec) _NOEXCEPT
+    recursive_directory_iterator& increment(error_code& __ec)
     { return __increment(&__ec); }
 
     _LIBCPP_FUNC_VIS directory_options options() const;
diff --git a/libcxx/test/std/experimental/filesystem/class.directory_iterator/directory_iterator.members/ctor.pass.cpp b/libcxx/test/std/experimental/filesystem/class.directory_iterator/directory_iterator.members/ctor.pass.cpp
index 830e8123150..4fd60887b54 100644
--- a/libcxx/test/std/experimental/filesystem/class.directory_iterator/directory_iterator.members/ctor.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.directory_iterator/directory_iterator.members/ctor.pass.cpp
@@ -15,8 +15,8 @@
 
 // explicit directory_iterator(const path& p);
 // directory_iterator(const path& p, directory_options options);
-// directory_iterator(const path& p, error_code& ec) noexcept;
-// directory_iterator(const path& p, directory_options options, error_code& ec) noexcept;
+// directory_iterator(const path& p, error_code& ec);
+// directory_iterator(const path& p, directory_options options, error_code& ec);
 
 #include <experimental/filesystem>
 #include <type_traits>
@@ -40,15 +40,22 @@ TEST_CASE(test_constructor_signatures)
     static_assert(std::is_constructible<D, path>::value, "");
     static_assert(!std::is_nothrow_constructible<D, path>::value, "");
 
-    // directory_iterator(path const&, error_code&) noexcept
-    static_assert(std::is_nothrow_constructible<D, path, std::error_code&>::value, "");
+    // directory_iterator(path const&, error_code&)
+    static_assert(std::is_constructible<D, path,
+        std::error_code&>::value, "");
+    static_assert(!std::is_nothrow_constructible<D, path,
+        std::error_code&>::value, "");
 
     // directory_iterator(path const&, directory_options);
     static_assert(std::is_constructible<D, path, directory_options>::value, "");
     static_assert(!std::is_nothrow_constructible<D, path, directory_options>::value, "");
 
-    // directory_iterator(path const&, directory_options, error_code&) noexcept
-    static_assert(std::is_nothrow_constructible<D, path, directory_options, std::error_code&>::value, "");
+    // directory_iterator(path const&, directory_options, error_code&)
+    static_assert(std::is_constructible<D, path, directory_options,
+        std::error_code&>::value, "");
+    static_assert(!std::is_nothrow_constructible<D, path, directory_options,
+        std::error_code&>::value, "");
+
 }
 
 TEST_CASE(test_construction_from_bad_path)
diff --git a/libcxx/test/std/experimental/filesystem/class.directory_iterator/directory_iterator.members/increment.pass.cpp b/libcxx/test/std/experimental/filesystem/class.directory_iterator/directory_iterator.members/increment.pass.cpp
index 589b4eca7ef..8d888717b10 100644
--- a/libcxx/test/std/experimental/filesystem/class.directory_iterator/directory_iterator.members/increment.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.directory_iterator/directory_iterator.members/increment.pass.cpp
@@ -14,7 +14,7 @@
 // class directory_iterator
 
 // directory_iterator& operator++();
-// directory_iterator& increment(error_code& ec) noexcept;
+// directory_iterator& increment(error_code& ec);
 
 #include <experimental/filesystem>
 #include <type_traits>
@@ -40,7 +40,7 @@ TEST_CASE(test_increment_signatures)
     ASSERT_NOT_NOEXCEPT(++d);
 
     ASSERT_SAME_TYPE(decltype(d.increment(ec)), directory_iterator&);
-    ASSERT_NOEXCEPT(d.increment(ec));
+    ASSERT_NOT_NOEXCEPT(d.increment(ec));
 }
 
 TEST_CASE(test_prefix_increment)
diff --git a/libcxx/test/std/experimental/filesystem/class.rec.dir.itr/rec.dir.itr.members/ctor.pass.cpp b/libcxx/test/std/experimental/filesystem/class.rec.dir.itr/rec.dir.itr.members/ctor.pass.cpp
index 8f6009d399c..1469dae049e 100644
--- a/libcxx/test/std/experimental/filesystem/class.rec.dir.itr/rec.dir.itr.members/ctor.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.rec.dir.itr/rec.dir.itr.members/ctor.pass.cpp
@@ -16,8 +16,8 @@
 //
 // explicit recursive_directory_iterator(const path& p);
 // recursive_directory_iterator(const path& p, directory_options options);
-// recursive_directory_iterator(const path& p, error_code& ec) noexcept;
-// recursive_directory_iterator(const path& p, directory_options options, error_code& ec) noexcept;
+// recursive_directory_iterator(const path& p, error_code& ec);
+// recursive_directory_iterator(const path& p, directory_options options, error_code& ec);
 
 
 #include <experimental/filesystem>
@@ -44,15 +44,19 @@ TEST_CASE(test_constructor_signatures)
     static_assert(std::is_constructible<D, path>::value, "");
     static_assert(!std::is_nothrow_constructible<D, path>::value, "");
 
-    // directory_iterator(path const&, error_code&) noexcept
-    static_assert(std::is_nothrow_constructible<D, path, std::error_code&>::value, "");
+    // directory_iterator(path const&, error_code&)
+    static_assert(std::is_constructible<D, path,
+        std::error_code&>::value, "");
+    static_assert(!std::is_nothrow_constructible<D, path,
+        std::error_code&>::value, "");
 
     // directory_iterator(path const&, directory_options);
     static_assert(std::is_constructible<D, path, directory_options>::value, "");
     static_assert(!std::is_nothrow_constructible<D, path, directory_options>::value, "");
 
-    // directory_iterator(path const&, directory_options, error_code&) noexcept
-    static_assert(std::is_nothrow_constructible<D, path, directory_options, std::error_code&>::value, "");
+    // directory_iterator(path const&, directory_options, error_code&)
+    static_assert(std::is_constructible<D, path, directory_options, std::error_code&>::value, "");
+    static_assert(!std::is_nothrow_constructible<D, path, directory_options, std::error_code&>::value, "");
 }
 
 TEST_CASE(test_construction_from_bad_path)
diff --git a/libcxx/test/std/experimental/filesystem/class.rec.dir.itr/rec.dir.itr.members/increment.pass.cpp b/libcxx/test/std/experimental/filesystem/class.rec.dir.itr/rec.dir.itr.members/increment.pass.cpp
index e91bd50f292..ea81ee25313 100644
--- a/libcxx/test/std/experimental/filesystem/class.rec.dir.itr/rec.dir.itr.members/increment.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/class.rec.dir.itr/rec.dir.itr.members/increment.pass.cpp
@@ -40,7 +40,7 @@ TEST_CASE(test_increment_signatures)
     ASSERT_NOT_NOEXCEPT(++d);
 
     ASSERT_SAME_TYPE(decltype(d.increment(ec)), recursive_directory_iterator&);
-    ASSERT_NOEXCEPT(d.increment(ec));
+    ASSERT_NOT_NOEXCEPT(d.increment(ec));
 }
 
 TEST_CASE(test_prefix_increment)
diff --git a/libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.copy/copy.pass.cpp b/libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.copy/copy.pass.cpp
index c9b42b3596a..8f44e0d5a23 100644
--- a/libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.copy/copy.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.copy/copy.pass.cpp
@@ -12,10 +12,10 @@
 // <experimental/filesystem>
 
 // void copy(const path& from, const path& to);
-// void copy(const path& from, const path& to, error_code& ec) noexcept;
+// void copy(const path& from, const path& to, error_code& ec);
 // void copy(const path& from, const path& to, copy_options options);
 // void copy(const path& from, const path& to, copy_options options,
-//           error_code& ec) noexcept;
+//           error_code& ec);
 
 #include <experimental/filesystem>
 #include <type_traits>
@@ -39,9 +39,9 @@ TEST_CASE(signature_test)
     std::error_code ec; ((void)ec);
     const copy_options opts{}; ((void)opts);
     ASSERT_NOT_NOEXCEPT(fs::copy(p, p));
-    ASSERT_NOEXCEPT(fs::copy(p, p, ec));
+    ASSERT_NOT_NOEXCEPT(fs::copy(p, p, ec));
     ASSERT_NOT_NOEXCEPT(copy(p, p, opts));
-    ASSERT_NOEXCEPT(copy(p, p, opts, ec));
+    ASSERT_NOT_NOEXCEPT(copy(p, p, opts, ec));
 }
 
 // There are 4 cases is the proposal for absolute path.
diff --git a/libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.is_empty/is_empty.pass.cpp b/libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.is_empty/is_empty.pass.cpp
index bc62086c2cf..2da163c3347 100644
--- a/libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.is_empty/is_empty.pass.cpp
+++ b/libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.is_empty/is_empty.pass.cpp
@@ -12,7 +12,7 @@
 // <experimental/filesystem>
 
 // bool is_empty(path const& p);
-// bool is_empty(path const& p, std::error_code& ec) noexcept;
+// bool is_empty(path const& p, std::error_code& ec);
 
 #include <experimental/filesystem>
 #include <type_traits>
@@ -30,7 +30,7 @@ TEST_CASE(signature_test)
 {
     const path p; ((void)p);
     std::error_code ec; ((void)ec);
-    ASSERT_NOEXCEPT(is_empty(p, ec));
+    ASSERT_NOT_NOEXCEPT(is_empty(p, ec));
     ASSERT_NOT_NOEXCEPT(is_empty(p));
 }