Address LWG 2849 and fix missing failure condition in copy_file.

Previously copy_file didn't handle the case where the input and
output were the same file.

llvm-svn: 324187

1 files changed, 20 insertions, 10 deletions

diff --git a/libcxx/src/experimental/filesystem/operations.cpp b/libcxx/src/experimental/filesystem/operations.cpp
index 91aee6ffbcb..2bc28c21dcf 100644
--- a/libcxx/src/experimental/filesystem/operations.cpp
+++ b/libcxx/src/experimental/filesystem/operations.cpp
@@ -263,18 +263,22 @@ void __copy(const path& from, const path& to, copy_options options,
 bool __copy_file(const path& from, const path& to, copy_options options,
                  std::error_code *ec)
 {
-    if (ec) ec->clear();
+    using StatT = struct ::stat;
+    if (ec)
+      ec->clear();
 
     std::error_code m_ec;
-    auto from_st = detail::posix_stat(from, &m_ec);
+    StatT from_stat;
+    auto from_st = detail::posix_stat(from, from_stat, &m_ec);
     if (not is_regular_file(from_st)) {
-        if (not m_ec)
-            m_ec = make_error_code(errc::not_supported);
-        set_or_throw(m_ec, ec, "copy_file", from, to);
-        return false;
+      if (not m_ec)
+        m_ec = make_error_code(errc::not_supported);
+      set_or_throw(m_ec, ec, "copy_file", from, to);
+      return false;
     }
 
-    auto to_st = detail::posix_stat(to, &m_ec);
+    StatT to_stat;
+    auto to_st = detail::posix_stat(to, to_stat, &m_ec);
     if (!status_known(to_st)) {
         set_or_throw(m_ec, ec, "copy_file", from, to);
         return false;
@@ -285,6 +289,11 @@ bool __copy_file(const path& from, const path& to, copy_options options,
         set_or_throw(make_error_code(errc::not_supported), ec, "copy_file", from, to);
         return false;
     }
+    if (to_exists && detail::stat_equivalent(from_stat, to_stat)) {
+      set_or_throw(make_error_code(errc::file_exists), ec, "copy_file", from,
+                   to);
+      return false;
+    }
     if (to_exists && bool(copy_options::skip_existing & options)) {
         return false;
     }
@@ -302,8 +311,9 @@ bool __copy_file(const path& from, const path& to, copy_options options,
         return detail::copy_file_impl(from, to, from_st.permissions(), ec);
     }
     else {
-        set_or_throw(make_error_code(errc::file_exists), ec, "copy", from, to);
-        return false;
+      set_or_throw(make_error_code(errc::file_exists), ec, "copy_file", from,
+                   to);
+      return false;
     }
 
     _LIBCPP_UNREACHABLE();
@@ -443,7 +453,7 @@ bool __equivalent(const path& p1, const path& p2, std::error_code *ec)
     if (!exists(s2))
       return make_unsupported_error();
     if (ec) ec->clear();
-    return (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
+    return detail::stat_equivalent(st1, st2);
 }