Function GetNewlyOpenedFileDescriptor

src/leveldb/util/env_posix_test.cc:112–124

Finds an FD open since a previous call to GetOpenFileDescriptors(). |baseline_open_fds| is the result of a previous GetOpenFileDescriptors() call. Assumes that exactly one FD was opened since that call. Returns void so the implementation can use ASSERT_EQ.

//
// Returns void so the implementation can use ASSERT_EQ.
void GetNewlyOpenedFileDescriptor(
    const std::unordered_set<int>& baseline_open_fds, int* result_fd) {
  std::unordered_set<int> open_fds;
  GetOpenFileDescriptors(&open_fds);
  for (int fd : baseline_open_fds) {
    ASSERT_EQ(1, open_fds.count(fd))
        << "Previously opened file descriptor was closed during test setup";
    open_fds.erase(fd);
  }
  ASSERT_EQ(1, open_fds.size())
      << "Expected exactly one newly opened file descriptor during test setup";
  *result_fd = *open_fds.begin();
}

// Check that a fork()+exec()-ed child process does not have an extra open FD.
void CheckCloseOnExecDoesNotLeakFDs(