Convert FileSystem::Open() to return Expected<FileUP>

Summary:
This patch converts FileSystem::Open from this prototype:

Status
Open(File &File, const FileSpec &file_spec, ...);

to this one:

llvm::Expected<std::unique_ptr<File>>
Open(const FileSpec &file_spec, ...);

This is beneficial on its own, as llvm::Expected is a more modern
and recommended error type than Status.  It is also a necessary step
towards https://reviews.llvm.org/D67891, and further developments
for lldb_private::File.

Reviewers: JDevlieghere, jasonmolenda, labath

Reviewed By: labath

Subscribers: mgorny, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D67996

llvm-svn: 373003

1 files changed, 14 insertions, 5 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
index 1fdd089dd5d..f60991034aa 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerCommon.cpp
@@ -512,14 +512,23 @@ GDBRemoteCommunicationServerCommon::Handle_vFile_Open(
         mode_t mode = packet.GetHexMaxU32(false, 0600);
         FileSpec path_spec(path);
         FileSystem::Instance().Resolve(path_spec);
-        File file;
         // Do not close fd.
-        Status error =
-            FileSystem::Instance().Open(file, path_spec, flags, mode, false);
-        const int save_errno = error.GetError();
+        auto file = FileSystem::Instance().Open(path_spec, flags, mode, false);
+
+        int save_errno = 0;
+        int descriptor = File::kInvalidDescriptor;
+        if (file) {
+          descriptor = file.get()->GetDescriptor();
+        } else {
+          std::error_code code = errorToErrorCode(file.takeError());
+          if (code.category() == std::system_category()) {
+            save_errno = code.value();
+          }
+        }
+
         StreamString response;
         response.PutChar('F');
-        response.Printf("%i", file.GetDescriptor());
+        response.Printf("%i", descriptor);
         if (save_errno)
           response.Printf(",%i", save_errno);
         return SendPacketNoLock(response.GetString());