HLE/FS: Return the proper error codes when opening files.

src/core/file_sys/archive_backend.h

@@ -76,9 +76,9 @@ public:
      * Open a file specified by its path, using the specified mode
      * @param path Path relative to the archive
      * @param mode Mode to open the file with
-     * @return Opened file, or nullptr
+     * @return Opened file, or error code
      */
-    virtual std::unique_ptr<FileBackend> OpenFile(const Path& path, const Mode mode) const = 0;
+    virtual ResultVal<std::unique_ptr<FileBackend>> OpenFile(const Path& path, const Mode mode) const = 0;
 
     /**
      * Delete a file specified by its path

src/core/file_sys/disk_archive.cpp

@@ -17,12 +17,13 @@
 
 namespace FileSys {
 
-std::unique_ptr<FileBackend> DiskArchive::OpenFile(const Path& path, const Mode mode) const {
+ResultVal<std::unique_ptr<FileBackend>> DiskArchive::OpenFile(const Path& path, const Mode mode) const {
     LOG_DEBUG(Service_FS, "called path=%s mode=%01X", path.DebugStr().c_str(), mode.hex);
     auto file = Common::make_unique<DiskFile>(*this, path, mode);
-    if (!file->Open())
-        return nullptr;
-    return std::move(file);
+    ResultCode result = file->Open();
+    if (result.IsError())
+        return result;
+    return MakeResult<std::unique_ptr<FileBackend>>(std::move(file));
 }
 
 ResultCode DiskArchive::DeleteFile(const Path& path) const {
@@ -103,25 +104,38 @@ DiskFile::DiskFile(const DiskArchive& archive, const Path& path, const Mode mode
     this->mode.hex = mode.hex;
 }
 
-bool DiskFile::Open() {
-    if (!mode.create_flag && !FileUtil::Exists(path)) {
-        LOG_ERROR(Service_FS, "Non-existing file %s can't be open without mode create.", path.c_str());
-        return false;
+ResultCode DiskFile::Open() {
+    if (FileUtil::IsDirectory(path))
+        return ResultCode(ErrorDescription::FS_NotAFile, ErrorModule::FS, ErrorSummary::Canceled, ErrorLevel::Status);
+
+    // Specifying only the Create flag is invalid
+    if (mode.create_flag && !mode.read_flag && !mode.write_flag) {
+        return ResultCode(ErrorDescription::FS_InvalidOpenFlags, ErrorModule::FS, ErrorSummary::Canceled, ErrorLevel::Status);
     }
 
-    std::string mode_string;
-    if (mode.create_flag)
-        mode_string = "w+";
-    else if (mode.write_flag)
-        mode_string = "r+"; // Files opened with Write access can be read from
+    if (!FileUtil::Exists(path)) {
+        if (!mode.create_flag) {
+            LOG_ERROR(Service_FS, "Non-existing file %s can't be open without mode create.", path.c_str());
+            return ResultCode(ErrorDescription::FS_NotFound, ErrorModule::FS, ErrorSummary::NotFound, ErrorLevel::Status);
+        } else {
+            // Create the file
+            FileUtil::CreateEmptyFile(path);
+        }
+    }
+
+    std::string mode_string = "";
+    if (mode.write_flag)
+        mode_string += "r+"; // Files opened with Write access can be read from
     else if (mode.read_flag)
-        mode_string = "r";
+        mode_string += "r";
 
     // Open the file in binary mode, to avoid problems with CR/LF on Windows systems
     mode_string += "b";
 
     file = Common::make_unique<FileUtil::IOFile>(path, mode_string.c_str());
-    return file->IsOpen();
+    if (file->IsOpen())
+        return RESULT_SUCCESS;
+    return ResultCode(ErrorDescription::FS_NotFound, ErrorModule::FS, ErrorSummary::NotFound, ErrorLevel::Status);
 }
 
 ResultVal<size_t> DiskFile::Read(const u64 offset, const size_t length, u8* buffer) const {

src/core/file_sys/disk_archive.h

@@ -33,7 +33,7 @@ public:
 
     virtual std::string GetName() const override { return "DiskArchive: " + mount_point; }
 
-    std::unique_ptr<FileBackend> OpenFile(const Path& path, const Mode mode) const override;
+    ResultVal<std::unique_ptr<FileBackend>> OpenFile(const Path& path, const Mode mode) const override;
     ResultCode DeleteFile(const Path& path) const override;
     bool RenameFile(const Path& src_path, const Path& dest_path) const override;
     bool DeleteDirectory(const Path& path) const override;
@@ -54,7 +54,7 @@ class DiskFile : public FileBackend {
 public:
     DiskFile(const DiskArchive& archive, const Path& path, const Mode mode);
 
-    bool Open() override;
+    ResultCode Open() override;
     ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
     ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
     u64 GetSize() const override;

src/core/file_sys/file_backend.h

@@ -21,9 +21,9 @@ public:
 
     /**
      * Open the file
-     * @return true if the file opened correctly
+     * @return Result of the file operation
      */
-    virtual bool Open() = 0;
+    virtual ResultCode Open() = 0;
 
     /**
      * Read data from the file

src/core/file_sys/ivfc_archive.cpp

@@ -20,8 +20,8 @@ std::string IVFCArchive::GetName() const {
     return "IVFC";
 }
 
-std::unique_ptr<FileBackend> IVFCArchive::OpenFile(const Path& path, const Mode mode) const {
-    return Common::make_unique<IVFCFile>(romfs_file, data_offset, data_size);
+ResultVal<std::unique_ptr<FileBackend>> IVFCArchive::OpenFile(const Path& path, const Mode mode) const {
+    return MakeResult<std::unique_ptr<FileBackend>>(Common::make_unique<IVFCFile>(romfs_file, data_offset, data_size));
 }
 
 ResultCode IVFCArchive::DeleteFile(const Path& path) const {

src/core/file_sys/ivfc_archive.h

@@ -34,7 +34,7 @@ public:
 
     std::string GetName() const override;
 
-    std::unique_ptr<FileBackend> OpenFile(const Path& path, const Mode mode) const override;
+    ResultVal<std::unique_ptr<FileBackend>> OpenFile(const Path& path, const Mode mode) const override;
     ResultCode DeleteFile(const Path& path) const override;
     bool RenameFile(const Path& src_path, const Path& dest_path) const override;
     bool DeleteDirectory(const Path& path) const override;
@@ -55,7 +55,7 @@ public:
     IVFCFile(std::shared_ptr<FileUtil::IOFile> file, u64 offset, u64 size)
         : romfs_file(file), data_offset(offset), data_size(size) {}
 
-    bool Open() override { return true; }
+    ResultCode Open() override { return RESULT_SUCCESS; }
     ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
     ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
     u64 GetSize() const override;

src/core/hle/service/fs/archive.cpp

@@ -307,13 +307,14 @@ ResultVal<Kernel::SharedPtr<File>> OpenFileFromArchive(ArchiveHandle archive_han
     if (archive == nullptr)
         return ERR_INVALID_HANDLE;
 
-    std::unique_ptr<FileSys::FileBackend> backend = archive->OpenFile(path, mode);
-    if (backend == nullptr) {
+    auto backend = archive->OpenFile(path, mode);
+    if (backend.Failed()) {
+        return backend.Code();
         return ResultCode(ErrorDescription::FS_NotFound, ErrorModule::FS,
                           ErrorSummary::NotFound, ErrorLevel::Status);
     }
 
-    auto file = Kernel::SharedPtr<File>(new File(std::move(backend), path));
+    auto file = Kernel::SharedPtr<File>(new File(backend.MoveFrom(), path));
     return MakeResult<Kernel::SharedPtr<File>>(std::move(file));
 }