drm_hwcomposer: Introduce SharedFd, use standard c++ RAII for UniqueFd
We use too much dup() system calls for present fence propagating.
Also when propagating acquire fence we use additional logic for
skipping such propagation for the validate/test cycle.
Both issues can be solved by introducing SharedFd, which will track
reference count of fd object.
After that the UniqueFd is used very rarely and can be simplified by
wrapping it into std::unique_ptr without caring too much of adding
an extra malloc/free operation.
Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
diff --git a/utils/fd.cpp b/utils/fd.cpp
new file mode 100644
index 0000000..395d3b2
--- /dev/null
+++ b/utils/fd.cpp
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "fd.h"
+
+namespace android {
+
+static void CloseFd(const int *fd) {
+ if (fd != nullptr) {
+ if (*fd >= 0)
+ close(*fd);
+
+ // NOLINTNEXTLINE(cppcoreguidelines-owning-memory)
+ delete fd;
+ }
+}
+
+auto MakeUniqueFd(int fd) -> UniqueFd {
+ if (fd < 0)
+ return {nullptr, CloseFd};
+
+ return {new int(fd), CloseFd};
+}
+
+auto MakeSharedFd(int fd) -> SharedFd {
+ if (fd < 0)
+ return {};
+
+ return {new int(fd), CloseFd};
+}
+
+auto DupFd(SharedFd const &fd) -> int {
+ if (!fd)
+ return -1;
+
+ return fcntl(*fd, F_DUPFD_CLOEXEC, 0);
+}
+
+} // namespace android