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

3 files changed, 23 insertions, 19 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
index 97f8388d771..bb7f77fa514 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp
@@ -949,11 +949,6 @@ PythonFile::PythonFile() : PythonObject() {}
 
 PythonFile::PythonFile(File &file, const char *mode) { Reset(file, mode); }
 
-PythonFile::PythonFile(const char *path, const char *mode) {
-  lldb_private::File file;
-  FileSystem::Instance().Open(file, FileSpec(path), GetOptionsFromMode(mode));
-  Reset(file, mode);
-}
 
 PythonFile::PythonFile(PyRefType type, PyObject *o) { Reset(type, o); }
 
@@ -1036,17 +1031,19 @@ uint32_t PythonFile::GetOptionsFromMode(llvm::StringRef mode) {
       .Default(0);
 }
 
-bool PythonFile::GetUnderlyingFile(File &file) const {
+FileUP PythonFile::GetUnderlyingFile() const {
   if (!IsValid())
-    return false;
+    return nullptr;
 
-  file.Close();
   // We don't own the file descriptor returned by this function, make sure the
   // File object knows about that.
   PythonString py_mode = GetAttributeValue("mode").AsType<PythonString>();
   auto options = PythonFile::GetOptionsFromMode(py_mode.GetString());
-  file.SetDescriptor(PyObject_AsFileDescriptor(m_py_obj), options, false);
-  return file.IsValid();
+  auto file = std::make_unique<File>(PyObject_AsFileDescriptor(m_py_obj),
+                                     options, false);
+  if (!file->IsValid())
+    return nullptr;
+  return file;
 }
 
 #endif
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
index 049ce90bb1b..3e1a3541bc7 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.h
@@ -455,7 +455,6 @@ class PythonFile : public PythonObject {
 public:
   PythonFile();
   PythonFile(File &file, const char *mode);
-  PythonFile(const char *path, const char *mode);
   PythonFile(PyRefType type, PyObject *o);
 
   ~PythonFile() override;
@@ -469,7 +468,7 @@ public:
 
   static uint32_t GetOptionsFromMode(llvm::StringRef mode);
 
-  bool GetUnderlyingFile(File &file) const;
+  lldb::FileUP GetUnderlyingFile() const;
 };
 
 } // namespace lldb_private
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index e8af9db2ce4..1d130672825 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -45,6 +45,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FormatAdapters.h"
 
 #include <memory>
 #include <mutex>
@@ -901,17 +902,24 @@ bool ScriptInterpreterPythonImpl::ExecuteOneLine(
         debugger.AdoptTopIOHandlerFilesIfInvalid(input_file_sp, output_file_sp,
                                                  error_file_sp);
     } else {
-      input_file_sp = std::make_shared<StreamFile>();
-      FileSystem::Instance().Open(input_file_sp->GetFile(),
+      auto nullin = FileSystem::Instance().Open(
                                   FileSpec(FileSystem::DEV_NULL),
                                   File::eOpenOptionRead);
-
-      output_file_sp = std::make_shared<StreamFile>();
-      FileSystem::Instance().Open(output_file_sp->GetFile(),
+      auto nullout = FileSystem::Instance().Open(
                                   FileSpec(FileSystem::DEV_NULL),
                                   File::eOpenOptionWrite);
-
-      error_file_sp = output_file_sp;
+      if (!nullin) {
+        result->AppendErrorWithFormatv("failed to open /dev/null: {0}\n",
+                                       llvm::fmt_consume(nullin.takeError()));
+        return false;
+      }
+      if (!nullout) {
+        result->AppendErrorWithFormatv("failed to open /dev/null: {0}\n",
+                                       llvm::fmt_consume(nullout.takeError()));
+        return false;
+      }
+      input_file_sp = std::make_shared<StreamFile>(std::move(nullin.get()));
+      error_file_sp = output_file_sp = std::make_shared<StreamFile>(std::move(nullout.get()));
     }
 
     FILE *in_file = input_file_sp->GetFile().GetStream();