FileView.hpp

// Copyright 2019 Pokitec
// All rights reserved.
 
#pragma once
 
#include "TTauri/Foundation/FileMapping.hpp"
#include "TTauri/Foundation/ResourceView.hpp"
#include <nonstd/span>
 
namespace tt {
 
class FileView : public ResourceView {
private:
    std::shared_ptr<FileMapping> fileMappingObject;
 
    std::shared_ptr<nonstd::span<std::byte>> _bytes;
 
    size_t _offset;
 
public:
    FileView(std::shared_ptr<FileMapping> const& mappingObject, size_t offset, size_t size);
    FileView(URL const &location, AccessMode accessMode=AccessMode::OpenForRead, size_t offset=0, size_t size=0);
    ~FileView() = default;
 
    FileView() = delete;
    FileView(FileView const &other) noexcept;
    FileView(FileView &&other) noexcept;
    FileView &operator=(FileView const &other) noexcept;
    FileView &operator=(FileView &&other) noexcept;
 
    [[nodiscard]] AccessMode accessMode() const noexcept { return fileMappingObject->accessMode(); }
 
    [[nodiscard]] URL const &location() const noexcept { return fileMappingObject->location(); }
 
    [[nodiscard]] size_t offset() const noexcept override { return _offset; }
 
    [[nodiscard]] size_t size() const noexcept override { return _bytes->size(); }
 
    [[nodiscard]] std::byte *data() noexcept { return _bytes->data(); }
 
    [[nodiscard]] std::byte const *data() const noexcept override { return _bytes->data(); }
 
    [[nodiscard]] nonstd::span<std::byte> bytes() noexcept { return *_bytes; }
 
    [[nodiscard]] nonstd::span<std::byte const> bytes() const noexcept override { return *_bytes; }
 
    [[nodiscard]] std::string_view string_view() noexcept {
        return std::string_view{reinterpret_cast<char *>(data()), size()};
    }
 
    [[nodiscard]] std::string_view string_view() const noexcept override {
        return std::string_view{reinterpret_cast<char const *>(data()), size()};
    }
 
    void flush(void* base, size_t size);
 
    [[nodiscard]] static std::unique_ptr<ResourceView> loadView(URL const &location) {
        return std::make_unique<FileView>(location);
    }
 
private:
    static void unmap(nonstd::span<std::byte> *bytes) noexcept;
 
    [[nodiscard]] static std::shared_ptr<FileMapping> findOrCreateFileMappingObject(URL const& path, AccessMode accessMode, size_t size);
};
 
}