LibCore: Make Core::File::open() return a Result<NNRP<File>, String>

It was impractical to return a RefPtr<File> since that left us no way
to extract the error string. This is usually needed for the UI, so the
old static open() got basically no use.

3 files changed, 9 insertions, 7 deletions

diff --git a/Libraries/LibCore/File.cpp b/Libraries/LibCore/File.cpp
index 782960407c..41056701f0 100644
--- a/Libraries/LibCore/File.cpp
+++ b/Libraries/LibCore/File.cpp
@@ -33,11 +33,11 @@
 
 namespace Core {
 
-RefPtr<File> File::open(const String& filename, IODevice::OpenMode mode, mode_t permissions)
+Result<NonnullRefPtr<File>, String> File::open(const String& filename, IODevice::OpenMode mode, mode_t permissions)
 {
     auto file = File::construct(filename);
     if (!file->open_impl(mode, permissions))
-        return nullptr;
+        return String(file->error_string());
     return file;
 }
 
diff --git a/Libraries/LibCore/File.h b/Libraries/LibCore/File.h
index aa94dc35cf..1e443debef 100644
--- a/Libraries/LibCore/File.h
+++ b/Libraries/LibCore/File.h
@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include <AK/Result.h>
 #include <AK/String.h>
 #include <LibCore/IODevice.h>
 
@@ -36,7 +37,7 @@ class File final : public IODevice {
 public:
     virtual ~File() override;
 
-    static RefPtr<File> open(const String& filename, IODevice::OpenMode, mode_t = 0644);
+    static Result<NonnullRefPtr<File>, String> open(const String& filename, IODevice::OpenMode, mode_t = 0644);
 
     String filename() const { return m_filename; }
     void set_filename(const StringView& filename) { m_filename = filename; }
diff --git a/Shell/main.cpp b/Shell/main.cpp
index 612a013a4a..cba616c0ca 100644
--- a/Shell/main.cpp
+++ b/Shell/main.cpp
@@ -993,12 +993,13 @@ void load_history()
 
 void save_history()
 {
-    auto history_file = Core::File::open(get_history_path(), Core::IODevice::WriteOnly, 0600);
-    if (!history_file)
+    auto file_or_error = Core::File::open(get_history_path(), Core::IODevice::WriteOnly, 0600);
+    if (file_or_error.is_error())
         return;
+    auto& file = *file_or_error.value();
     for (const auto& line : editor.history()) {
-        history_file->write(line);
-        history_file->write("\n");
+        file.write(line);
+        file.write("\n");
     }
 }