Implement LWG 2672.

llvm-svn: 284314

libcxx/src/experimental/filesystem/operations.cpp

@@ -472,13 +472,25 @@ bool __fs_is_empty(const path& p, std::error_code *ec)
     std::error_code m_ec;
     struct ::stat pst;
     auto st = detail::posix_stat(p, pst, &m_ec);
-    if (is_directory(st))
+    if (m_ec) {
-        return directory_iterator(p) == directory_iterator{};
+        set_or_throw(m_ec, ec, "is_empty", p);
+        return false;
+    }
+    else if (!is_directory(st) && !is_regular_file(st)) {
+        m_ec = make_error_code(errc::not_supported);
+        set_or_throw(m_ec, ec, "is_empty");
+        return false;
+    }
+    else if (is_directory(st)) {
+        auto it = ec ? directory_iterator(p, *ec) : directory_iterator(p);
+        if (ec && *ec)
+            return false;
+        return it == directory_iterator{};
+    }
     else if (is_regular_file(st))
         return static_cast<std::uintmax_t>(pst.st_size) == 0;
-    // else
+
-    set_or_throw(m_ec, ec, "is_empty", p);
+    _LIBCPP_UNREACHABLE();
-    return false;
 }
 
 

libcxx/test/std/experimental/filesystem/fs.op.funcs/fs.op.is_empty/is_empty.pass.cpp

@@ -77,4 +77,33 @@ TEST_CASE(test_is_empty_fails)
     TEST_CHECK_THROW(filesystem_error, is_empty(dir2));
 }
 
+TEST_CASE(test_directory_access_denied)
+{
+    scoped_test_env env;
+    const path dir = env.create_dir("dir");
+    const path file1 = env.create_file("dir/file", 42);
+    permissions(dir, perms::none);
+
+    std::error_code ec = GetTestEC();
+    TEST_CHECK(is_empty(dir, ec) == false);
+    TEST_CHECK(ec);
+    TEST_CHECK(ec != GetTestEC());
+
+    TEST_CHECK_THROW(filesystem_error, is_empty(dir));
+}
+
+
+TEST_CASE(test_fifo_fails)
+{
+    scoped_test_env env;
+    const path fifo = env.create_fifo("fifo");
+
+    std::error_code ec = GetTestEC();
+    TEST_CHECK(is_empty(fifo, ec) == false);
+    TEST_CHECK(ec);
+    TEST_CHECK(ec != GetTestEC());
+
+    TEST_CHECK_THROW(filesystem_error, is_empty(fifo));
+}
+
 TEST_SUITE_END()

libcxx/www/upcoming_meeting.html

@@ -90,7 +90,7 @@
 	 <tr><td><a href="http://wg21.link/LWG2598">2598</a></td><td>addressof works on temporaries</td><td>Issaquah</td><td>Patch ready</td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2664">2664</a></td><td>operator/ (and other append) semantics not useful if argument has root</td><td>Issaquah</td><td>Nothing to do</td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2665">2665</a></td><td>remove_filename() post condition is incorrect</td><td>Issaquah</td><td>See Below</td></tr>
-	 <tr><td><a href="http://wg21.link/LWG2672">2672</a></td><td>Should is_empty use error_code in its specification?</td><td>Issaquah</td><td></td></tr>
+	 <tr><td><a href="http://wg21.link/LWG2672">2672</a></td><td>Should is_empty use error_code in its specification?</td><td>Issaquah</td><td>We already do this</td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2678">2678</a></td><td>std::filesystem enum classes overspecified</td><td>Issaquah</td><td>Nothing to do</td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2679">2679</a></td><td>Inconsistent Use of Effects and Equivalent To</td><td>Issaquah</td><td>Nothing to do</td></tr>
 	 <tr><td><a href="http://wg21.link/LWG2680">2680</a></td><td>Add "Equivalent to" to filesystem</td><td>Issaquah</td><td></td></tr>
@@ -168,7 +168,7 @@
 <li>2598 - Patch and tests ready</li>
 <li>2664 - No change needed. _LIBCPP_DEBUG mode tests the new requirements.</li>
 <li>2665 - PR is incorrect as-is. We implement a modified version</li>
-<li>2672 - File System; Eric?</li>
+<li>2672 - Patch and tests in tree. </li>
 <li>2678 - File System; Eric?</li>
 <li>2679 - This is just wording cleanup. </li>
 <li>2680 - File System; Eric?</li>