vfs: Add readonly layer class

Takes a VirtualDir/File and makes its API read only.

src/core/CMakeLists.txt

@@ -86,6 +86,8 @@ add_library(core STATIC
     file_sys/vfs_offset.h
     file_sys/vfs_real.cpp
     file_sys/vfs_real.h
+    file_sys/vfs_ro_layer.cpp
+    file_sys/vfs_ro_layer.h
     file_sys/vfs_static.h
     file_sys/vfs_types.h
     file_sys/vfs_vector.cpp

src/core/file_sys/vfs_ro_layer.cpp

@@ -0,0 +1,181 @@
+// Copyright 2019 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "core/file_sys/vfs_ro_layer.h"
+
+namespace FileSys {
+
+ReadOnlyVfsFileLayer::ReadOnlyVfsFileLayer(VirtualFile base) : base(std::move(base)) {}
+
+ReadOnlyVfsFileLayer::~ReadOnlyVfsFileLayer() = default;
+
+std::string ReadOnlyVfsFileLayer::GetName() const {
+    return base->GetName();
+}
+
+std::size_t ReadOnlyVfsFileLayer::GetSize() const {
+    return base->GetSize();
+}
+
+bool ReadOnlyVfsFileLayer::Resize(std::size_t new_size) {
+    return false;
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsFileLayer::GetContainingDirectory() const {
+    // Make containing read-only to prevent escaping the layer by getting containing and then
+    // getting this file again.
+    return std::make_shared<ReadOnlyVfsDirectoryLayer>(base->GetContainingDirectory());
+}
+
+bool ReadOnlyVfsFileLayer::IsWritable() const {
+    return false;
+}
+
+bool ReadOnlyVfsFileLayer::IsReadable() const {
+    return base->IsReadable();
+}
+
+std::size_t ReadOnlyVfsFileLayer::Read(u8* data, std::size_t length, std::size_t offset) const {
+    return base->Read(data, length, offset);
+}
+
+std::size_t ReadOnlyVfsFileLayer::Write(const u8* data, std::size_t length, std::size_t offset) {
+    return 0;
+}
+
+bool ReadOnlyVfsFileLayer::Rename(std::string_view name) {
+    return false;
+}
+
+std::string ReadOnlyVfsFileLayer::GetFullPath() const {
+    return base->GetFullPath();
+}
+
+ReadOnlyVfsDirectoryLayer::ReadOnlyVfsDirectoryLayer(VirtualDir base) : base(std::move(base)) {}
+
+ReadOnlyVfsDirectoryLayer::~ReadOnlyVfsDirectoryLayer() = default;
+
+std::vector<std::shared_ptr<VfsFile>> ReadOnlyVfsDirectoryLayer::GetFiles() const {
+    std::vector<VirtualFile> out;
+    const auto in = base->GetFiles();
+    std::transform(in.begin(), in.end(), std::back_inserter(out),
+                   [](const VirtualFile& i) { return std::make_shared<ReadOnlyVfsFileLayer>(i); });
+    return out;
+}
+
+std::vector<std::shared_ptr<VfsDirectory>> ReadOnlyVfsDirectoryLayer::GetSubdirectories() const {
+    std::vector<VirtualDir> out;
+    const auto in = base->GetSubdirectories();
+    std::transform(in.begin(), in.end(), std::back_inserter(out), [](const VirtualDir& i) {
+        return std::make_shared<ReadOnlyVfsDirectoryLayer>(i);
+    });
+    return out;
+}
+
+std::string ReadOnlyVfsDirectoryLayer::GetName() const {
+    return base->GetName();
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectoryLayer::GetParentDirectory() const {
+    return std::make_shared<ReadOnlyVfsDirectoryLayer>(base->GetParentDirectory());
+}
+
+std::shared_ptr<VfsFile> ReadOnlyVfsDirectoryLayer::GetFileRelative(std::string_view path) const {
+    return std::make_shared<ReadOnlyVfsFileLayer>(base->GetFileRelative(path));
+}
+
+std::shared_ptr<VfsFile> ReadOnlyVfsDirectoryLayer::GetFileAbsolute(std::string_view path) const {
+    return std::make_shared<ReadOnlyVfsFileLayer>(base->GetFileAbsolute(path));
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectoryLayer::GetDirectoryRelative(
+    std::string_view path) const {
+    return std::make_shared<ReadOnlyVfsDirectoryLayer>(base->GetDirectoryRelative(path));
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectoryLayer::GetDirectoryAbsolute(
+    std::string_view path) const {
+    return std::make_shared<ReadOnlyVfsDirectoryLayer>(base->GetDirectoryAbsolute(path));
+}
+
+std::shared_ptr<VfsFile> ReadOnlyVfsDirectoryLayer::GetFile(std::string_view name) const {
+    return std::make_shared<ReadOnlyVfsFileLayer>(base->GetFile(name));
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectoryLayer::GetSubdirectory(
+    std::string_view name) const {
+    return std::make_shared<ReadOnlyVfsDirectoryLayer>(base->GetSubdirectory(name));
+}
+
+bool ReadOnlyVfsDirectoryLayer::IsRoot() const {
+    return base->IsRoot();
+}
+
+std::size_t ReadOnlyVfsDirectoryLayer::GetSize() const {
+    return base->GetSize();
+}
+
+bool ReadOnlyVfsDirectoryLayer::Copy(std::string_view src, std::string_view dest) {
+    return false;
+}
+
+std::string ReadOnlyVfsDirectoryLayer::GetFullPath() const {
+    return base->GetFullPath();
+}
+
+bool ReadOnlyVfsDirectoryLayer::IsWritable() const {
+    return false;
+}
+
+bool ReadOnlyVfsDirectoryLayer::IsReadable() const {
+    return base->IsReadable();
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectoryLayer::CreateSubdirectory(std::string_view name) {
+    return nullptr;
+}
+
+std::shared_ptr<VfsFile> ReadOnlyVfsDirectoryLayer::CreateFile(std::string_view name) {
+    return nullptr;
+}
+
+std::shared_ptr<VfsFile> ReadOnlyVfsDirectoryLayer::CreateFileAbsolute(std::string_view path) {
+    return nullptr;
+}
+
+std::shared_ptr<VfsFile> ReadOnlyVfsDirectoryLayer::CreateFileRelative(std::string_view path) {
+    return nullptr;
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectoryLayer::CreateDirectoryAbsolute(
+    std::string_view path) {
+    return nullptr;
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectoryLayer::CreateDirectoryRelative(
+    std::string_view path) {
+    return nullptr;
+}
+
+bool ReadOnlyVfsDirectoryLayer::DeleteSubdirectory(std::string_view name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectoryLayer::DeleteSubdirectoryRecursive(std::string_view name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectoryLayer::CleanSubdirectoryRecursive(std::string_view name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectoryLayer::DeleteFile(std::string_view name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectoryLayer::Rename(std::string_view name) {
+    return false;
+}
+
+} // namespace FileSys

src/core/file_sys/vfs_ro_layer.h

@@ -0,0 +1,73 @@
+// Copyright 2019 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include "core/file_sys/vfs.h"
+
+namespace FileSys {
+
+// Class that wraps a VfsFile making it read-only
+class ReadOnlyVfsFileLayer : public VfsFile {
+public:
+    explicit ReadOnlyVfsFileLayer(VirtualFile base);
+    ~ReadOnlyVfsFileLayer() override;
+
+    std::string GetName() const override;
+    std::size_t GetSize() const override;
+    bool Resize(std::size_t new_size) override;
+    std::shared_ptr<VfsDirectory> GetContainingDirectory() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::size_t Read(u8* data, std::size_t length, std::size_t offset) const override;
+    std::size_t Write(const u8* data, std::size_t length, std::size_t offset) override;
+    bool Rename(std::string_view name) override;
+
+    std::string GetFullPath() const override;
+
+private:
+    VirtualFile base;
+};
+
+// Class that wraps a VfsDirectory making it and its children read only.
+class ReadOnlyVfsDirectoryLayer : public ReadOnlyVfsDirectory {
+public:
+    explicit ReadOnlyVfsDirectoryLayer(VirtualDir base);
+    ~ReadOnlyVfsDirectoryLayer() override;
+
+    std::vector<std::shared_ptr<VfsFile>> GetFiles() const override;
+    std::vector<std::shared_ptr<VfsDirectory>> GetSubdirectories() const override;
+    std::string GetName() const override;
+    std::shared_ptr<VfsDirectory> GetParentDirectory() const override;
+
+    std::shared_ptr<VfsFile> GetFileRelative(std::string_view path) const override;
+    std::shared_ptr<VfsFile> GetFileAbsolute(std::string_view path) const override;
+    std::shared_ptr<VfsDirectory> GetDirectoryRelative(std::string_view path) const override;
+    std::shared_ptr<VfsDirectory> GetDirectoryAbsolute(std::string_view path) const override;
+    std::shared_ptr<VfsFile> GetFile(std::string_view name) const override;
+    std::shared_ptr<VfsDirectory> GetSubdirectory(std::string_view name) const override;
+    bool IsRoot() const override;
+    std::size_t GetSize() const override;
+    bool Copy(std::string_view src, std::string_view dest) override;
+    std::string GetFullPath() const override;
+    bool IsWritable() const override;
+    bool IsReadable() const override;
+    std::shared_ptr<VfsDirectory> CreateSubdirectory(std::string_view name) override;
+    std::shared_ptr<VfsFile> CreateFile(std::string_view name) override;
+    std::shared_ptr<VfsFile> CreateFileAbsolute(std::string_view path) override;
+    std::shared_ptr<VfsFile> CreateFileRelative(std::string_view path) override;
+    std::shared_ptr<VfsDirectory> CreateDirectoryAbsolute(std::string_view path) override;
+    std::shared_ptr<VfsDirectory> CreateDirectoryRelative(std::string_view path) override;
+    bool DeleteSubdirectory(std::string_view name) override;
+    bool DeleteSubdirectoryRecursive(std::string_view name) override;
+    bool CleanSubdirectoryRecursive(std::string_view name) override;
+    bool DeleteFile(std::string_view name) override;
+    bool Rename(std::string_view name) override;
+
+private:
+    VirtualDir base;
+};
+
+} // namespace FileSys