1 files changed, 167 insertions, 0 deletions
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..6dd0f6439
--- /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:
+    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) {
+        std::vector<u8> output = backend->ReadBytes(size, offset);
+        *out = output.size();
+        buffer = output.data();
+        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