FileHandle.h

#pragma once
 
#if !defined( EMSCRIPTEN )
 
#include "../StringView.h"
 
#if defined( _WIN32 )
#include <WinSock2.h>
#undef GetObject
#endif
 
#include <memory>
 
namespace Cogs {
  class COGSFOUNDATION_API FileHandle {
  public:
    using Ptr = std::shared_ptr<FileHandle>;
 
    enum class OpenMode {
      Create,
      CreateAlways,
      Open,
      OpenAlways
    };
 
    enum class AccessMode {
      Read,
      Write
    };
 
    enum class ProtectionMode {
      ReadOnly,
    };
 
    FileHandle() = default;
    ~FileHandle();
    FileHandle(const FileHandle &) = delete;
    FileHandle(FileHandle &&move) noexcept
    {
      assert(move.mappedMemory == nullptr);
#if defined( _WIN32 )
      fileHandle = move.fileHandle;
      move.fileHandle = INVALID_HANDLE_VALUE;
#elif defined( __linux__ ) || defined(__APPLE__)
      fileDescriptor = move.fileDescriptor;
      move.fileDescriptor = -1;
#endif
    }
    FileHandle &operator=(const FileHandle &) = delete;
    FileHandle &operator=(FileHandle &&move) noexcept
    {
      assert(mappedMemory == nullptr);
      assert(move.mappedMemory == nullptr);
      close();
#if defined( _WIN32 )
      fileHandle = move.fileHandle;
      move.fileHandle = INVALID_HANDLE_VALUE;
#elif defined( __linux__ ) || defined(__APPLE__)
      fileDescriptor = move.fileDescriptor;
      move.fileDescriptor = -1;
#endif
      return *this;
    }
 
    static Ptr open(std::string_view path, OpenMode openMode, AccessMode accessMode);
    void       close();
 
    size_t getSize() const;
    void*  getMappedMemory() const { return mappedMemory; }
 
    bool isOpen() const;
    bool isMapped() const          { return mappedMemory != nullptr; }
 
    bool write(const void *buffer, size_t size, size_t &written);
    bool read(void *buffer, size_t size, size_t &read);
 
    void* map(ProtectionMode protectionMode, size_t offset, size_t size);
    void  unmap();
 
    private:
#if defined( _WIN32 )
    HANDLE  fileHandle = INVALID_HANDLE_VALUE;
    HANDLE  mapHandle = nullptr;
#elif defined( __linux__ ) || defined(__APPLE__)
    int     fileDescriptor = -1;
    size_t  mappedSize = 0;
#endif
    void*   mappedMemory = nullptr;
  };
}
 
#endif  // !EMSCRIPTEN