Add support for decrypted NCA files (#567)

* Start to add NCA support in loader

* More nca stuff

* More changes to nca.cpp

* Now identifies decrypted NCA cont.

* Game list fixes and more structs and stuff

* More updates to Nca class

* Now reads ExeFs (i think)

* ACTUALLY LOADS EXEFS!

* RomFS loads and games execute

* Cleanup and Finalize

* plumbing, cleanup and testing

* fix some things that i didnt think of before

* Preliminary Review Changes

* Review changes for bunnei and subv

src/core/loader/nca.h

@@ -0,0 +1,49 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <string>
+#include "common/common_types.h"
+#include "core/file_sys/partition_filesystem.h"
+#include "core/file_sys/program_metadata.h"
+#include "core/hle/kernel/kernel.h"
+#include "core/loader/loader.h"
+
+namespace Loader {
+
+class Nca;
+
+/// Loads an NCA file
+class AppLoader_NCA final : public AppLoader {
+public:
+    AppLoader_NCA(FileUtil::IOFile&& file, std::string filepath);
+
+    /**
+     * Returns the type of the file
+     * @param file FileUtil::IOFile open file
+     * @param filepath Path of the file that we are opening.
+     * @return FileType found, or FileType::Error if this loader doesn't know it
+     */
+    static FileType IdentifyType(FileUtil::IOFile& file, const std::string& filepath);
+
+    FileType GetFileType() override {
+        return IdentifyType(file, filepath);
+    }
+
+    ResultStatus Load(Kernel::SharedPtr<Kernel::Process>& process) override;
+
+    ResultStatus ReadRomFS(std::shared_ptr<FileUtil::IOFile>& romfs_file, u64& offset,
+                           u64& size) override;
+
+    ~AppLoader_NCA();
+
+private:
+    std::string filepath;
+    FileSys::ProgramMetadata metadata;
+
+    std::unique_ptr<Nca> nca;
+};
+
+} // namespace Loader