3 files changed, 464 insertions, 0 deletions
diff --git a/src/core/file_sys/fsa/fs_i_directory.h b/src/core/file_sys/fsa/fs_i_directory.h
new file mode 100644
index 000000000..c8e895eab
--- /dev/null
+++ b/src/core/file_sys/fsa/fs_i_directory.h
@@ -0,0 +1,91 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/common_types.h"
+#include "core/file_sys/errors.h"
+#include "core/file_sys/fs_directory.h"
+#include "core/file_sys/fs_file.h"
+#include "core/file_sys/fs_filesystem.h"
+#include "core/file_sys/savedata_factory.h"
+#include "core/file_sys/vfs/vfs.h"
+#include "core/hle/result.h"
+
+namespace FileSys::Fsa {
+
+class IDirectory {
+public:
+    explicit IDirectory(VirtualDir backend_, OpenDirectoryMode mode)
+        : backend(std::move(backend_)) {
+        // TODO(DarkLordZach): Verify that this is the correct behavior.
+        // Build entry index now to save time later.
+        if (True(mode & OpenDirectoryMode::Directory)) {
+            BuildEntryIndex(backend->GetSubdirectories(), DirectoryEntryType::Directory);
+        }
+        if (True(mode & OpenDirectoryMode::File)) {
+            BuildEntryIndex(backend->GetFiles(), DirectoryEntryType::File);
+        }
+    }
+    virtual ~IDirectory() {}
+
+    Result Read(s64* out_count, DirectoryEntry* out_entries, s64 max_entries) {
+        R_UNLESS(out_count != nullptr, ResultNullptrArgument);
+        if (max_entries == 0) {
+            *out_count = 0;
+            R_SUCCEED();
+        }
+        R_UNLESS(out_entries != nullptr, ResultNullptrArgument);
+        R_UNLESS(max_entries > 0, ResultInvalidArgument);
+        R_RETURN(this->DoRead(out_count, out_entries, max_entries));
+    }
+
+    Result GetEntryCount(s64* out) {
+        R_UNLESS(out != nullptr, ResultNullptrArgument);
+        R_RETURN(this->DoGetEntryCount(out));
+    }
+
+private:
+    Result DoRead(s64* out_count, DirectoryEntry* out_entries, s64 max_entries) {
+        const u64 actual_entries =
+            std::min(static_cast<u64>(max_entries), entries.size() - next_entry_index);
+        const auto* begin = reinterpret_cast<u8*>(entries.data() + next_entry_index);
+        const auto* end = reinterpret_cast<u8*>(entries.data() + next_entry_index + actual_entries);
+        const auto range_size = static_cast<std::size_t>(std::distance(begin, end));
+
+        next_entry_index += actual_entries;
+        *out_count = actual_entries;
+
+        std::memcpy(out_entries, begin, range_size);
+
+        R_SUCCEED();
+    }
+
+    Result DoGetEntryCount(s64* out) {
+        *out = entries.size() - next_entry_index;
+        R_SUCCEED();
+    }
+
+    // TODO: Remove this when VFS is gone
+    template <typename T>
+    void BuildEntryIndex(const std::vector<T>& new_data, DirectoryEntryType type) {
+        entries.reserve(entries.size() + new_data.size());
+
+        for (const auto& new_entry : new_data) {
+            auto name = new_entry->GetName();
+
+            if (type == DirectoryEntryType::File && name == GetSaveDataSizeFileName()) {
+                continue;
+            }
+
+            entries.emplace_back(name, static_cast<s8>(type),
+                                 type == DirectoryEntryType::Directory ? 0 : new_entry->GetSize());
+        }
+    }
+
+    VirtualDir backend;
+    std::vector<DirectoryEntry> entries;
+    u64 next_entry_index = 0;
+};
+
+} // namespace FileSys::Fsa
diff --git a/src/core/file_sys/fsa/fs_i_file.h b/src/core/file_sys/fsa/fs_i_file.h
new file mode 100644
index 000000000..1188ae8ca
--- /dev/null
+++ b/src/core/file_sys/fsa/fs_i_file.h
@@ -0,0 +1,167 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "common/overflow.h"
+#include "core/file_sys/errors.h"
+#include "core/file_sys/fs_file.h"
+#include "core/file_sys/fs_filesystem.h"
+#include "core/file_sys/fs_operate_range.h"
+#include "core/file_sys/vfs/vfs.h"
+#include "core/file_sys/vfs/vfs_types.h"
+#include "core/hle/result.h"
+
+namespace FileSys::Fsa {
+
+class IFile {
+public:
+    explicit IFile(VirtualFile backend_) : backend(std::move(backend_)) {}
+    virtual ~IFile() {}
+
+    Result Read(size_t* out, s64 offset, void* buffer, size_t size, const ReadOption& option) {
+        // Check that we have an output pointer
+        R_UNLESS(out != nullptr, ResultNullptrArgument);
+
+        // If we have nothing to read, just succeed
+        if (size == 0) {
+            *out = 0;
+            R_SUCCEED();
+        }
+
+        // Check that the read is valid
+        R_UNLESS(buffer != nullptr, ResultNullptrArgument);
+        R_UNLESS(offset >= 0, ResultOutOfRange);
+        R_UNLESS(Common::CanAddWithoutOverflow<s64>(offset, size), ResultOutOfRange);
+
+        // Do the read
+        R_RETURN(this->DoRead(out, offset, buffer, size, option));
+    }
+
+    Result Read(size_t* out, s64 offset, void* buffer, size_t size) {
+        R_RETURN(this->Read(out, offset, buffer, size, ReadOption::None));
+    }
+
+    Result GetSize(s64* out) {
+        R_UNLESS(out != nullptr, ResultNullptrArgument);
+        R_RETURN(this->DoGetSize(out));
+    }
+
+    Result Flush() {
+        R_RETURN(this->DoFlush());
+    }
+
+    Result Write(s64 offset, const void* buffer, size_t size, const WriteOption& option) {
+        // Handle the zero-size case
+        if (size == 0) {
+            if (option.HasFlushFlag()) {
+                R_TRY(this->Flush());
+            }
+            R_SUCCEED();
+        }
+
+        // Check the write is valid
+        R_UNLESS(buffer != nullptr, ResultNullptrArgument);
+        R_UNLESS(offset >= 0, ResultOutOfRange);
+        R_UNLESS(Common::CanAddWithoutOverflow<s64>(offset, size), ResultOutOfRange);
+
+        R_RETURN(this->DoWrite(offset, buffer, size, option));
+    }
+
+    Result SetSize(s64 size) {
+        R_UNLESS(size >= 0, ResultOutOfRange);
+        R_RETURN(this->DoSetSize(size));
+    }
+
+    Result OperateRange(void* dst, size_t dst_size, OperationId op_id, s64 offset, s64 size,
+                        const void* src, size_t src_size) {
+        R_RETURN(this->DoOperateRange(dst, dst_size, op_id, offset, size, src, src_size));
+    }
+
+    Result OperateRange(OperationId op_id, s64 offset, s64 size) {
+        R_RETURN(this->DoOperateRange(nullptr, 0, op_id, offset, size, nullptr, 0));
+    }
+
+protected:
+    Result DryRead(size_t* out, s64 offset, size_t size, const ReadOption& option,
+                   OpenMode open_mode) {
+        // Check that we can read
+        R_UNLESS(static_cast<u32>(open_mode & OpenMode::Read) != 0, ResultReadNotPermitted);
+
+        // Get the file size, and validate our offset
+        s64 file_size = 0;
+        R_TRY(this->DoGetSize(std::addressof(file_size)));
+        R_UNLESS(offset <= file_size, ResultOutOfRange);
+
+        *out = static_cast<size_t>(std::min(file_size - offset, static_cast<s64>(size)));
+        R_SUCCEED();
+    }
+
+    Result DrySetSize(s64 size, OpenMode open_mode) {
+        // Check that we can write
+        R_UNLESS(static_cast<u32>(open_mode & OpenMode::Write) != 0, ResultWriteNotPermitted);
+        R_SUCCEED();
+    }
+
+    Result DryWrite(bool* out_append, s64 offset, size_t size, const WriteOption& option,
+                    OpenMode open_mode) {
+        // Check that we can write
+        R_UNLESS(static_cast<u32>(open_mode & OpenMode::Write) != 0, ResultWriteNotPermitted);
+
+        // Get the file size
+        s64 file_size = 0;
+        R_TRY(this->DoGetSize(&file_size));
+
+        // Determine if we need to append
+        *out_append = false;
+        if (file_size < offset + static_cast<s64>(size)) {
+            R_UNLESS(static_cast<u32>(open_mode & OpenMode::AllowAppend) != 0,
+                     ResultFileExtensionWithoutOpenModeAllowAppend);
+            *out_append = true;
+        }
+
+        R_SUCCEED();
+    }
+
+private:
+    Result DoRead(size_t* out, s64 offset, void* buffer, size_t size, const ReadOption& option) {
+        const auto read_size = backend->Read(static_cast<u8*>(buffer), size, offset);
+        *out = read_size;
+
+        R_SUCCEED();
+    }
+
+    Result DoGetSize(s64* out) {
+        *out = backend->GetSize();
+        R_SUCCEED();
+    }
+
+    Result DoFlush() {
+        // Exists for SDK compatibiltity -- No need to flush file.
+        R_SUCCEED();
+    }
+
+    Result DoWrite(s64 offset, const void* buffer, size_t size, const WriteOption& option) {
+        const std::size_t written = backend->Write(static_cast<const u8*>(buffer), size, offset);
+
+        ASSERT_MSG(written == size,
+                   "Could not write all bytes to file (requested={:016X}, actual={:016X}).", size,
+                   written);
+
+        R_SUCCEED();
+    }
+
+    Result DoSetSize(s64 size) {
+        backend->Resize(size);
+        R_SUCCEED();
+    }
+
+    Result DoOperateRange(void* dst, size_t dst_size, OperationId op_id, s64 offset, s64 size,
+                          const void* src, size_t src_size) {
+        R_THROW(ResultNotImplemented);
+    }
+
+    VirtualFile backend;
+};
+
+} // namespace FileSys::Fsa
diff --git a/src/core/file_sys/fsa/fs_i_filesystem.h b/src/core/file_sys/fsa/fs_i_filesystem.h
new file mode 100644
index 000000000..8172190f4
--- /dev/null
+++ b/src/core/file_sys/fsa/fs_i_filesystem.h
@@ -0,0 +1,206 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "core/file_sys/errors.h"
+#include "core/file_sys/fs_filesystem.h"
+#include "core/file_sys/fs_path.h"
+#include "core/file_sys/vfs/vfs_types.h"
+#include "core/hle/result.h"
+#include "core/hle/service/filesystem/filesystem.h"
+
+namespace FileSys::Fsa {
+
+class IFile;
+class IDirectory;
+
+enum class QueryId : u32 {
+    SetConcatenationFileAttribute = 0,
+    UpdateMac = 1,
+    IsSignedSystemPartitionOnSdCardValid = 2,
+    QueryUnpreparedFileInformation = 3,
+};
+
+class IFileSystem {
+public:
+    explicit IFileSystem(VirtualDir backend_) : backend{std::move(backend_)} {}
+    virtual ~IFileSystem() {}
+
+    Result CreateFile(const Path& path, s64 size, CreateOption option) {
+        R_UNLESS(size >= 0, ResultOutOfRange);
+        R_RETURN(this->DoCreateFile(path, size, static_cast<int>(option)));
+    }
+
+    Result CreateFile(const Path& path, s64 size) {
+        R_RETURN(this->CreateFile(path, size, CreateOption::None));
+    }
+
+    Result DeleteFile(const Path& path) {
+        R_RETURN(this->DoDeleteFile(path));
+    }
+
+    Result CreateDirectory(const Path& path) {
+        R_RETURN(this->DoCreateDirectory(path));
+    }
+
+    Result DeleteDirectory(const Path& path) {
+        R_RETURN(this->DoDeleteDirectory(path));
+    }
+
+    Result DeleteDirectoryRecursively(const Path& path) {
+        R_RETURN(this->DoDeleteDirectoryRecursively(path));
+    }
+
+    Result RenameFile(const Path& old_path, const Path& new_path) {
+        R_RETURN(this->DoRenameFile(old_path, new_path));
+    }
+
+    Result RenameDirectory(const Path& old_path, const Path& new_path) {
+        R_RETURN(this->DoRenameDirectory(old_path, new_path));
+    }
+
+    Result GetEntryType(DirectoryEntryType* out, const Path& path) {
+        R_RETURN(this->DoGetEntryType(out, path));
+    }
+
+    Result OpenFile(VirtualFile* out_file, const Path& path, OpenMode mode) {
+        R_UNLESS(out_file != nullptr, ResultNullptrArgument);
+        R_UNLESS(static_cast<u32>(mode & OpenMode::ReadWrite) != 0, ResultInvalidOpenMode);
+        R_UNLESS(static_cast<u32>(mode & ~OpenMode::All) == 0, ResultInvalidOpenMode);
+        R_RETURN(this->DoOpenFile(out_file, path, mode));
+    }
+
+    Result OpenDirectory(VirtualDir* out_dir, const Path& path, OpenDirectoryMode mode) {
+        R_UNLESS(out_dir != nullptr, ResultNullptrArgument);
+        R_UNLESS(static_cast<u64>(mode & OpenDirectoryMode::All) != 0, ResultInvalidOpenMode);
+        R_UNLESS(static_cast<u64>(
+                     mode & ~(OpenDirectoryMode::All | OpenDirectoryMode::NotRequireFileSize)) == 0,
+                 ResultInvalidOpenMode);
+        R_RETURN(this->DoOpenDirectory(out_dir, path, mode));
+    }
+
+    Result Commit() {
+        R_RETURN(this->DoCommit());
+    }
+
+    Result GetFreeSpaceSize(s64* out, const Path& path) {
+        R_UNLESS(out != nullptr, ResultNullptrArgument);
+        R_RETURN(this->DoGetFreeSpaceSize(out, path));
+    }
+
+    Result GetTotalSpaceSize(s64* out, const Path& path) {
+        R_UNLESS(out != nullptr, ResultNullptrArgument);
+        R_RETURN(this->DoGetTotalSpaceSize(out, path));
+    }
+
+    Result CleanDirectoryRecursively(const Path& path) {
+        R_RETURN(this->DoCleanDirectoryRecursively(path));
+    }
+
+    Result GetFileTimeStampRaw(FileTimeStampRaw* out, const Path& path) {
+        R_UNLESS(out != nullptr, ResultNullptrArgument);
+        R_RETURN(this->DoGetFileTimeStampRaw(out, path));
+    }
+
+    Result QueryEntry(char* dst, size_t dst_size, const char* src, size_t src_size, QueryId query,
+                      const Path& path) {
+        R_RETURN(this->DoQueryEntry(dst, dst_size, src, src_size, query, path));
+    }
+
+    // These aren't accessible as commands
+    Result CommitProvisionally(s64 counter) {
+        R_RETURN(this->DoCommitProvisionally(counter));
+    }
+
+    Result Rollback() {
+        R_RETURN(this->DoRollback());
+    }
+
+    Result Flush() {
+        R_RETURN(this->DoFlush());
+    }
+
+private:
+    Result DoCreateFile(const Path& path, s64 size, int flags) {
+        R_RETURN(backend.CreateFile(path.GetString(), size));
+    }
+
+    Result DoDeleteFile(const Path& path) {
+        R_RETURN(backend.DeleteFile(path.GetString()));
+    }
+
+    Result DoCreateDirectory(const Path& path) {
+        R_RETURN(backend.CreateDirectory(path.GetString()));
+    }
+
+    Result DoDeleteDirectory(const Path& path) {
+        R_RETURN(backend.DeleteDirectory(path.GetString()));
+    }
+
+    Result DoDeleteDirectoryRecursively(const Path& path) {
+        R_RETURN(backend.DeleteDirectoryRecursively(path.GetString()));
+    }
+
+    Result DoRenameFile(const Path& old_path, const Path& new_path) {
+        R_RETURN(backend.RenameFile(old_path.GetString(), new_path.GetString()));
+    }
+
+    Result DoRenameDirectory(const Path& old_path, const Path& new_path) {
+        R_RETURN(backend.RenameDirectory(old_path.GetString(), new_path.GetString()));
+    }
+
+    Result DoGetEntryType(DirectoryEntryType* out, const Path& path) {
+        R_RETURN(backend.GetEntryType(out, path.GetString()));
+    }
+
+    Result DoOpenFile(VirtualFile* out_file, const Path& path, OpenMode mode) {
+        R_RETURN(backend.OpenFile(out_file, path.GetString(), mode));
+    }
+
+    Result DoOpenDirectory(VirtualDir* out_directory, const Path& path, OpenDirectoryMode mode) {
+        R_RETURN(backend.OpenDirectory(out_directory, path.GetString()));
+    }
+
+    Result DoCommit() {
+        R_THROW(ResultNotImplemented);
+    }
+
+    Result DoGetFreeSpaceSize(s64* out, const Path& path) {
+        R_THROW(ResultNotImplemented);
+    }
+
+    Result DoGetTotalSpaceSize(s64* out, const Path& path) {
+        R_THROW(ResultNotImplemented);
+    }
+
+    Result DoCleanDirectoryRecursively(const Path& path) {
+        R_RETURN(backend.CleanDirectoryRecursively(path.GetString()));
+    }
+
+    Result DoGetFileTimeStampRaw(FileTimeStampRaw* out, const Path& path) {
+        R_RETURN(backend.GetFileTimeStampRaw(out, path.GetString()));
+    }
+
+    Result DoQueryEntry(char* dst, size_t dst_size, const char* src, size_t src_size, QueryId query,
+                        const Path& path) {
+        R_THROW(ResultNotImplemented);
+    }
+
+    // These aren't accessible as commands
+    Result DoCommitProvisionally(s64 counter) {
+        R_THROW(ResultNotImplemented);
+    }
+
+    Result DoRollback() {
+        R_THROW(ResultNotImplemented);
+    }
+
+    Result DoFlush() {
+        R_THROW(ResultNotImplemented);
+    }
+
+    Service::FileSystem::VfsDirectoryServiceWrapper backend;
+};
+
+} // namespace FileSys::Fsa