[lldb] [ConnectionFileDescriptorPosix] Use a single NativeFile

[mgorny]

Summary

Replace separate read and write NativeFile instances with a single
instance shared for reading and writing. There is no clear indication
why two instances were used in the first place, and replacing them
with just one does not seem to cause any regressions in tests or manual
'process connect file://...'.

[labath]

At one point these didn't use to be shared pointers so we couldn't copy them like this, though I am still unclear as to why we need two of them in the first place.

[mgorny]

In D111314#3050383, @labath wrote:

At one point these didn't use to be shared pointers so we couldn't copy them like this, though I am still unclear as to why we need two of them in the first place.

Actually, I've asked you on IRC yesterday if you think I should replace them with one field, or if we should keep the separate semantics for some possible use in the future.

[labath]

In D111314#3050392, @mgorny wrote:

In D111314#3050383, @labath wrote:

At one point these didn't use to be shared pointers so we couldn't copy them like this, though I am still unclear as to why we need two of them in the first place.

Actually, I've asked you on IRC yesterday if you think I should replace them with one field, or if we should keep the separate semantics for some possible use in the future.

Yeah, and I don't really know the answer to that.

But if you make a patch to merge the two, I'll probably approve it. :)

lldb/source/Host/posix/ConnectionFileDescriptorPosix.cpp

ConnectionFileDescriptor::ConnectionFileDescriptor(bool child_processes_inherit)
   LLDB_LOGF(log, "%p ConnectionFileDescriptor::ConnectionFileDescriptor ()",
             static_cast<void *>(this));
 }
 
 ConnectionFileDescriptor::ConnectionFileDescriptor(int fd, bool owns_fd)
     : Connection(), m_pipe(), m_mutex(), m_shutting_down(false),
       m_waiting_for_accept(false), m_child_processes_inherit(false) {
   m_write_sp =
-      std::make_shared<NativeFile>(fd, File::eOpenOptionWriteOnly, owns_fd);
-  m_read_sp =
-      std::make_shared<NativeFile>(fd, File::eOpenOptionReadOnly, false);
+      std::make_shared<NativeFile>(fd, File::eOpenOptionReadWrite, owns_fd);
+  m_read_sp = m_write_sp;
 
   Log *log(lldb_private::GetLogIfAnyCategoriesSet(LIBLLDB_LOG_CONNECTION |
                                                   LIBLLDB_LOG_OBJECT));
   LLDB_LOGF(log,
             "%p ConnectionFileDescriptor::ConnectionFileDescriptor (fd = "
             "%i, owns_fd = %i)",
             static_cast<void *>(this), fd, owns_fd);
   OpenCommandPipe();
else if ((addr = GetURLAddress(path, FD_SCHEME))) {
           int resuse;
           bool is_socket =
               !!tcp_socket->GetOption(SOL_SOCKET, SO_REUSEADDR, resuse);
           if (is_socket) {
             m_read_sp = std::move(tcp_socket);
             m_write_sp = m_read_sp;
           } else {
             m_read_sp = std::make_shared<NativeFile>(
-                fd, File::eOpenOptionReadOnly, false);
-            m_write_sp = std::make_shared<NativeFile>(
-                fd, File::eOpenOptionWriteOnly, false);
+                fd, File::eOpenOptionReadWrite, false);
+            m_write_sp = m_read_sp;
           }
           m_uri = std::string(*addr);
           return eConnectionStatusSuccess;
         }
       }
 
       if (error_ptr)
         error_ptr->SetErrorStringWithFormat("invalid file descriptor: \"%s\"",
else if ((addr = GetURLAddress(path, FD_SCHEME))) {
       int flags = ::fcntl(fd, F_GETFL, 0);
       if (flags >= 0) {
         if ((flags & O_NONBLOCK) == 0) {
           flags |= O_NONBLOCK;
           ::fcntl(fd, F_SETFL, flags);
         }
       }
       m_read_sp =
-          std::make_shared<NativeFile>(fd, File::eOpenOptionReadOnly, true);
-      m_write_sp =
-          std::make_shared<NativeFile>(fd, File::eOpenOptionWriteOnly, false);
+          std::make_shared<NativeFile>(fd, File::eOpenOptionReadWrite, true);
+      m_write_sp = m_read_sp;
       return eConnectionStatusSuccess;
     }
 #endif
     if (error_ptr)
       error_ptr->SetErrorStringWithFormat("unsupported connection URL: '%s'",
                                           path.str().c_str());
     return eConnectionStatusError;
   }