Virtual Filesystem (#597)

* Add VfsFile and VfsDirectory classes

* Finish abstract Vfs classes

* Implement RealVfsFile (computer fs backend)

* Finish RealVfsFile and RealVfsDirectory

* Finished OffsetVfsFile

* More changes

* Fix import paths

* Major refactor

* Remove double const

* Use experimental/filesystem or filesystem depending on compiler

* Port partition_filesystem

* More changes

* More Overhaul

* FSP_SRV fixes

* Fixes and testing

* Try to get filesystem to compile

* Filesystem on linux

* Remove std::filesystem and document/test

* Compile fixes

* Missing include

* Bug fixes

* Fixes

* Rename v_file and v_dir

* clang-format fix

* Rename NGLOG_* to LOG_*

* Most review changes

* Fix TODO

* Guess 'main' to be Directory by filename

1 files changed, 187 insertions, 0 deletions

diff --git a/src/core/file_sys/vfs.cpp b/src/core/file_sys/vfs.cpp
new file mode 100644
index 000000000..c99071d6a
--- /dev/null
+++ b/src/core/file_sys/vfs.cpp
@@ -0,0 +1,187 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <numeric>
+#include "common/file_util.h"
+#include "core/file_sys/vfs.h"
+
+namespace FileSys {
+
+VfsFile::~VfsFile() = default;
+
+std::string VfsFile::GetExtension() const {
+    return FileUtil::GetExtensionFromFilename(GetName());
+}
+
+VfsDirectory::~VfsDirectory() = default;
+
+boost::optional<u8> VfsFile::ReadByte(size_t offset) const {
+    u8 out{};
+    size_t size = Read(&out, 1, offset);
+    if (size == 1)
+        return out;
+
+    return boost::none;
+}
+
+std::vector<u8> VfsFile::ReadBytes(size_t size, size_t offset) const {
+    std::vector<u8> out(size);
+    size_t read_size = Read(out.data(), size, offset);
+    out.resize(read_size);
+    return out;
+}
+
+std::vector<u8> VfsFile::ReadAllBytes() const {
+    return ReadBytes(GetSize());
+}
+
+bool VfsFile::WriteByte(u8 data, size_t offset) {
+    return Write(&data, 1, offset) == 1;
+}
+
+size_t VfsFile::WriteBytes(std::vector<u8> data, size_t offset) {
+    return Write(data.data(), data.size(), offset);
+}
+
+std::shared_ptr<VfsFile> VfsDirectory::GetFileRelative(const std::string& path) const {
+    auto vec = FileUtil::SplitPathComponents(path);
+    vec.erase(std::remove_if(vec.begin(), vec.end(), [](const auto& str) { return str.empty(); }),
+              vec.end());
+    if (vec.empty())
+        return nullptr;
+    if (vec.size() == 1)
+        return GetFile(vec[0]);
+    auto dir = GetSubdirectory(vec[0]);
+    for (size_t i = 1; i < vec.size() - 1; ++i) {
+        if (dir == nullptr)
+            return nullptr;
+        dir = dir->GetSubdirectory(vec[i]);
+    }
+    if (dir == nullptr)
+        return nullptr;
+    return dir->GetFile(vec.back());
+}
+
+std::shared_ptr<VfsFile> VfsDirectory::GetFileAbsolute(const std::string& path) const {
+    if (IsRoot())
+        return GetFileRelative(path);
+
+    return GetParentDirectory()->GetFileAbsolute(path);
+}
+
+std::shared_ptr<VfsDirectory> VfsDirectory::GetDirectoryRelative(const std::string& path) const {
+    auto vec = FileUtil::SplitPathComponents(path);
+    vec.erase(std::remove_if(vec.begin(), vec.end(), [](const auto& str) { return str.empty(); }),
+              vec.end());
+    if (vec.empty())
+        // return std::shared_ptr<VfsDirectory>(this);
+        return nullptr;
+    auto dir = GetSubdirectory(vec[0]);
+    for (size_t i = 1; i < vec.size(); ++i) {
+        dir = dir->GetSubdirectory(vec[i]);
+    }
+    return dir;
+}
+
+std::shared_ptr<VfsDirectory> VfsDirectory::GetDirectoryAbsolute(const std::string& path) const {
+    if (IsRoot())
+        return GetDirectoryRelative(path);
+
+    return GetParentDirectory()->GetDirectoryAbsolute(path);
+}
+
+std::shared_ptr<VfsFile> VfsDirectory::GetFile(const std::string& name) const {
+    const auto& files = GetFiles();
+    const auto iter = std::find_if(files.begin(), files.end(),
+                                   [&name](const auto& file1) { return name == file1->GetName(); });
+    return iter == files.end() ? nullptr : *iter;
+}
+
+std::shared_ptr<VfsDirectory> VfsDirectory::GetSubdirectory(const std::string& name) const {
+    const auto& subs = GetSubdirectories();
+    const auto iter = std::find_if(subs.begin(), subs.end(),
+                                   [&name](const auto& file1) { return name == file1->GetName(); });
+    return iter == subs.end() ? nullptr : *iter;
+}
+
+bool VfsDirectory::IsRoot() const {
+    return GetParentDirectory() == nullptr;
+}
+
+size_t VfsDirectory::GetSize() const {
+    const auto& files = GetFiles();
+    const auto file_total =
+        std::accumulate(files.begin(), files.end(), 0ull,
+                        [](const auto& f1, const auto& f2) { return f1 + f2->GetSize(); });
+
+    const auto& sub_dir = GetSubdirectories();
+    const auto subdir_total =
+        std::accumulate(sub_dir.begin(), sub_dir.end(), 0ull,
+                        [](const auto& f1, const auto& f2) { return f1 + f2->GetSize(); });
+
+    return file_total + subdir_total;
+}
+
+bool VfsDirectory::DeleteSubdirectoryRecursive(const std::string& name) {
+    auto dir = GetSubdirectory(name);
+    if (dir == nullptr)
+        return false;
+
+    bool success = true;
+    for (const auto& file : dir->GetFiles()) {
+        if (!DeleteFile(file->GetName()))
+            success = false;
+    }
+
+    for (const auto& sdir : dir->GetSubdirectories()) {
+        if (!dir->DeleteSubdirectoryRecursive(sdir->GetName()))
+            success = false;
+    }
+
+    return success;
+}
+
+bool VfsDirectory::Copy(const std::string& src, const std::string& dest) {
+    const auto f1 = GetFile(src);
+    auto f2 = CreateFile(dest);
+    if (f1 == nullptr || f2 == nullptr)
+        return false;
+
+    if (!f2->Resize(f1->GetSize())) {
+        DeleteFile(dest);
+        return false;
+    }
+
+    return f2->WriteBytes(f1->ReadAllBytes()) == f1->GetSize();
+}
+
+bool ReadOnlyVfsDirectory::IsWritable() const {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::IsReadable() const {
+    return true;
+}
+
+std::shared_ptr<VfsDirectory> ReadOnlyVfsDirectory::CreateSubdirectory(const std::string& name) {
+    return nullptr;
+}
+
+std::shared_ptr<VfsFile> ReadOnlyVfsDirectory::CreateFile(const std::string& name) {
+    return nullptr;
+}
+
+bool ReadOnlyVfsDirectory::DeleteSubdirectory(const std::string& name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::DeleteFile(const std::string& name) {
+    return false;
+}
+
+bool ReadOnlyVfsDirectory::Rename(const std::string& name) {
+    return false;
+}
+} // namespace FileSys